using /opt/libgit2 for test builds

Signed-off-by: Jeff Carr <jcarr@wit.com>

.gitignore

@@ -0,0 +1,4 @@
+/static-build/
+/dynamic-build/
+
+go.*

Build_bundled_static.go

@@ -0,0 +1,17 @@
+//go:build static && !system_libgit2
+// +build static,!system_libgit2
+
+package git
+
+/*
+#cgo windows CFLAGS: -I${SRCDIR}/static-build/install/include/
+#cgo windows LDFLAGS: -L${SRCDIR}/static-build/install/lib/ -lgit2 -lwinhttp -lws2_32 -lole32 -lrpcrt4 -lcrypt32
+#cgo !windows pkg-config: --static ${SRCDIR}/static-build/install/lib/pkgconfig/libgit2.pc
+#cgo CFLAGS: -DLIBGIT2_STATIC
+#include <git2.h>
+
+#if LIBGIT2_VER_MAJOR != 1 || LIBGIT2_VER_MINOR < 5 || LIBGIT2_VER_MINOR > 5
+# error "Invalid libgit2 version; this libgit2 supports libgit2 between v1.5.0 and v1.5.0"
+#endif
+*/
+import "C"

Build_system_dynamic.go

@@ -0,0 +1,14 @@
+//go:build !static
+// +build !static
+
+package git
+
+/*
+#cgo pkg-config: libgit2
+#cgo CFLAGS: -DLIBGIT2_DYNAMIC -I/opt/libgit2/include
+#cgo LDFLAGS: -L/opt/libgit2 -lgit2
+#include <git2.h>
+
+
+*/
+import "C"

Build_system_static.go

@@ -0,0 +1,15 @@
+//go:build static && system_libgit2
+// +build static,system_libgit2
+
+package git
+
+/*
+#cgo pkg-config: libgit2 --static
+#cgo CFLAGS: -DLIBGIT2_STATIC
+#include <git2.h>
+
+#if LIBGIT2_VER_MAJOR != 1 || LIBGIT2_VER_MINOR < 5 || LIBGIT2_VER_MINOR > 5
+# error "Invalid libgit2 version; this libgit2 supports libgit2 between v1.5.0 and v1.5.0"
+#endif
+*/
+import "C"

LICENSE

@@ -1,6 +1,6 @@
 The MIT License
 
-Copyright (c) 2013 The git2go contributors
+Copyright (c) 2013 The libgit2 contributors
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

Makefile

@@ -0,0 +1,70 @@
+TEST_ARGS ?= --count=1
+
+PKG_CONFIG_PATH=/opt/libgit2/
+
+default: goimports test
+
+goimports:
+	goimports -w *.go
+
+generate: static-build/install/lib/libgit2.a
+	go generate --tags "static" ./...
+
+# System library
+# ==============
+# This uses whatever version of libgit2 can be found in the system.
+test:
+	-go-mod-clean # go install go.wit.com/apps/go-mod-clean@latest
+	go run script/check-MakeGitError-thread-lock.go
+	LD_LIBRARY_PATH=/opt/libgit2 PKG_CONFIG_PATH=/opt/libgit2/ go test -v -x $(TEST_ARGS) ./...
+
+add-remote:
+	git remote add git2go https://github.com/libgit2/git2go.git
+
+install:
+	go install ./...
+
+clean:
+	rm go.*
+
+# Bundled dynamic library
+# =======================
+# In order to avoid having to manipulate `git_dynamic.go`, which would prevent
+# the system-wide libgit2.so from being used in a sort of ergonomic way, this
+# instead moves the complexity of overriding the paths so that the built
+# libraries can be found by the build and tests.
+.PHONY: build-libgit2-dynamic
+build-libgit2-dynamic:
+	./script/build-libgit2-dynamic.sh
+
+dynamic-build/install/lib/libgit2.so:
+	./script/build-libgit2-dynamic.sh
+
+test-dynamic: dynamic-build/install/lib/libgit2.so
+	PKG_CONFIG_PATH=dynamic-build/install/lib/pkgconfig \
+			go run script/check-MakeGitError-thread-lock.go
+	PKG_CONFIG_PATH=dynamic-build/install/lib/pkgconfig \
+			LD_LIBRARY_PATH=dynamic-build/install/lib \
+			go test $(TEST_ARGS) ./...
+
+install-dynamic: dynamic-build/install/lib/libgit2.so
+	PKG_CONFIG_PATH=dynamic-build/install/lib/pkgconfig \
+			go install ./...
+
+# Bundled static library
+# ======================
+# This is mostly used in tests, but can also be used to provide a
+# statically-linked library with the bundled version of libgit2.
+.PHONY: build-libgit2-static
+build-libgit2-static:
+	./script/build-libgit2-static.sh
+
+static-build/install/lib/libgit2.a:
+	./script/build-libgit2-static.sh
+
+test-static: static-build/install/lib/libgit2.a
+	go run script/check-MakeGitError-thread-lock.go
+	go test --tags "static" $(TEST_ARGS) ./...
+
+install-static: static-build/install/lib/libgit2.a
+	go install --tags "static" ./...

README.md

@@ -1,21 +1,69 @@
-git2go
+GO libgit2
 ======
+[![GoDoc](https://godoc.org/go.wit.com/lib/libgit2?status.svg)](http://godoc.org/go.wit.com/lib/libgit2) [![Build Status](https://travis-ci.org/libgit2/libgit2.svg?branch=main)](https://travis-ci.org/libgit2/libgit2)
 
-Go bindings for [libgit2](http://libgit2.github.com/). These bindings are for top-of-the-branch libgit2, and they move fast, things may or may not work. Operator get me Beijing-jing-jing-jing!
+Go bindings for [libgit2](http://libgit2.github.com/).
+
+### Updated 2024/12/16
+
+### Which Go version to use
+
+* This package is updated to work against libgit2 version 1.8 on Debian sid
+* There is one line commented out which needs to be fixed in remote.go
+* some of the tests seem to run
+
+```sh
+go install go.wit.com/apps/go-clone@latest
+go install go.wit.com/apps/go-mod-clean@latest
+go-clone --recusive go.wit.com/lib/libgit2
+```
+
+
+### Which branch to send Pull requests to
+
+TODO: not sure yet
 
 Installing
 ----------
 
-Just `go get github.com/libgit2/git2go`. You'll need to have top-of-the-branch libgit2 from development installed in your system and available via `pkg-config`. These bindings are in sync with the top of `development`.
+This project wraps the functionality provided by libgit2. It thus needs it in order to perform the work.
+
+This project wraps the functionality provided by libgit2. If you're using a versioned branch, install it to your system via your system's package manager and then install libgit2.
+
+
+### Versioned branch, dynamic linking
+
+When linking dynamically against a released version of libgit2, install it via your system's package manager. CGo will take care of finding its pkg-config file and set up the linking. Import via Go modules, e.g. to work against libgit2 v1.2
+
+```go
+    goimports -w *.go
+```
+
+Parallelism and network operations
+----------------------------------
+
+libgit2 may use OpenSSL and LibSSH2 for performing encrypted network connections. For now, libgit2 asks libgit2 to set locking for OpenSSL. This makes HTTPS connections thread-safe, but it is fragile and will likely stop doing it soon. This may also make SSH connections thread-safe if your copy of libssh2 is linked against OpenSSL. Check libgit2's `THREADSAFE.md` for more information.
+
+Running the tests
+-----------------
+
+For the stable version, `go test` will work as usual. For the `main` branch, similarly to installing, running the tests requires building a local libgit2 library, so the Makefile provides a wrapper that makes sure it's built
+
+    make test-static
+
+Alternatively, you can build the library manually first and then run the tests
+
+    make install-static
+    go test -v -tags static ./...
 
 License
 -------
 
-M to the I to the T. See the LICENSE file if you've never seen a MIT license before.
+M to the I to the T. See the LICENSE file if you've never seen an MIT license before.
 
 Authors
 -------
 
-- Carlos Martín (@carlosmn)
-- Vicent Martí (@vmg)
+- Carlos Martín (github@carlosmn)
+- Vicent Martí (github@vmg)
 

blame.go

@@ -0,0 +1,166 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+type BlameOptions struct {
+	Flags              BlameOptionsFlag
+	MinMatchCharacters uint16
+	NewestCommit       *Oid
+	OldestCommit       *Oid
+	MinLine            uint32
+	MaxLine            uint32
+}
+
+func DefaultBlameOptions() (BlameOptions, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	opts := C.git_blame_options{}
+	ecode := C.git_blame_options_init(&opts, C.GIT_BLAME_OPTIONS_VERSION)
+	if ecode < 0 {
+		return BlameOptions{}, MakeGitError(ecode)
+	}
+
+	return BlameOptions{
+		Flags:              BlameOptionsFlag(opts.flags),
+		MinMatchCharacters: uint16(opts.min_match_characters),
+		NewestCommit:       newOidFromC(&opts.newest_commit),
+		OldestCommit:       newOidFromC(&opts.oldest_commit),
+		MinLine:            uint32(opts.min_line),
+		MaxLine:            uint32(opts.max_line),
+	}, nil
+}
+
+type BlameOptionsFlag uint32
+
+const (
+	BlameNormal                      BlameOptionsFlag = C.GIT_BLAME_NORMAL
+	BlameTrackCopiesSameFile         BlameOptionsFlag = C.GIT_BLAME_TRACK_COPIES_SAME_FILE
+	BlameTrackCopiesSameCommitMoves  BlameOptionsFlag = C.GIT_BLAME_TRACK_COPIES_SAME_COMMIT_MOVES
+	BlameTrackCopiesSameCommitCopies BlameOptionsFlag = C.GIT_BLAME_TRACK_COPIES_SAME_COMMIT_COPIES
+	BlameTrackCopiesAnyCommitCopies  BlameOptionsFlag = C.GIT_BLAME_TRACK_COPIES_ANY_COMMIT_COPIES
+	BlameFirstParent                 BlameOptionsFlag = C.GIT_BLAME_FIRST_PARENT
+	BlameUseMailmap                  BlameOptionsFlag = C.GIT_BLAME_USE_MAILMAP
+	BlameIgnoreWhitespace            BlameOptionsFlag = C.GIT_BLAME_IGNORE_WHITESPACE
+)
+
+func (v *Repository) BlameFile(path string, opts *BlameOptions) (*Blame, error) {
+	var blamePtr *C.git_blame
+
+	var copts *C.git_blame_options
+	if opts != nil {
+		copts = &C.git_blame_options{
+			version:              C.GIT_BLAME_OPTIONS_VERSION,
+			flags:                C.uint32_t(opts.Flags),
+			min_match_characters: C.uint16_t(opts.MinMatchCharacters),
+			min_line:             C.size_t(opts.MinLine),
+			max_line:             C.size_t(opts.MaxLine),
+		}
+		if opts.NewestCommit != nil {
+			copts.newest_commit = *opts.NewestCommit.toC()
+		}
+		if opts.OldestCommit != nil {
+			copts.oldest_commit = *opts.OldestCommit.toC()
+		}
+	}
+
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_blame_file(&blamePtr, v.ptr, cpath, copts)
+	runtime.KeepAlive(v)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newBlameFromC(blamePtr), nil
+}
+
+type Blame struct {
+	doNotCompare
+	ptr *C.git_blame
+}
+
+func (blame *Blame) HunkCount() int {
+	ret := int(C.git_blame_get_hunk_count(blame.ptr))
+	runtime.KeepAlive(blame)
+
+	return ret
+}
+
+func (blame *Blame) HunkByIndex(index int) (BlameHunk, error) {
+	ptr := C.git_blame_get_hunk_byindex(blame.ptr, C.uint32_t(index))
+	runtime.KeepAlive(blame)
+	if ptr == nil {
+		return BlameHunk{}, ErrInvalid
+	}
+	return blameHunkFromC(ptr), nil
+}
+
+func (blame *Blame) HunkByLine(lineno int) (BlameHunk, error) {
+	ptr := C.git_blame_get_hunk_byline(blame.ptr, C.size_t(lineno))
+	runtime.KeepAlive(blame)
+	if ptr == nil {
+		return BlameHunk{}, ErrInvalid
+	}
+	return blameHunkFromC(ptr), nil
+}
+
+func newBlameFromC(ptr *C.git_blame) *Blame {
+	if ptr == nil {
+		return nil
+	}
+
+	blame := &Blame{
+		ptr: ptr,
+	}
+
+	runtime.SetFinalizer(blame, (*Blame).Free)
+	return blame
+}
+
+func (blame *Blame) Free() error {
+	if blame.ptr == nil {
+		return ErrInvalid
+	}
+	runtime.SetFinalizer(blame, nil)
+	C.git_blame_free(blame.ptr)
+	blame.ptr = nil
+	return nil
+}
+
+type BlameHunk struct {
+	LinesInHunk          uint16
+	FinalCommitId        *Oid
+	FinalStartLineNumber uint16
+	FinalSignature       *Signature
+	OrigCommitId         *Oid
+	OrigPath             string
+	OrigStartLineNumber  uint16
+	OrigSignature        *Signature
+	Boundary             bool
+}
+
+func blameHunkFromC(hunk *C.git_blame_hunk) BlameHunk {
+	return BlameHunk{
+		LinesInHunk:          uint16(hunk.lines_in_hunk),
+		FinalCommitId:        newOidFromC(&hunk.final_commit_id),
+		FinalStartLineNumber: uint16(hunk.final_start_line_number),
+		FinalSignature:       newSignatureFromC(hunk.final_signature),
+		OrigCommitId:         newOidFromC(&hunk.orig_commit_id),
+		OrigPath:             C.GoString(hunk.orig_path),
+		OrigStartLineNumber:  uint16(hunk.orig_start_line_number),
+		OrigSignature:        newSignatureFromC(hunk.orig_signature),
+		Boundary:             hunk.boundary == 1,
+	}
+}

blame_test.go

@@ -0,0 +1,73 @@
+package git
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestBlame(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId1, _ := seedTestRepo(t, repo)
+	commitId2, _ := updateReadme(t, repo, "foo\nbar\nbaz\n")
+
+	opts := BlameOptions{
+		NewestCommit: commitId2,
+		OldestCommit: nil,
+		MinLine:      1,
+		MaxLine:      3,
+	}
+	blame, err := repo.BlameFile("README", &opts)
+	checkFatal(t, err)
+	defer blame.Free()
+	if blame.HunkCount() != 2 {
+		t.Errorf("got hunk count %d, want 2", blame.HunkCount())
+	}
+
+	wantHunk1 := BlameHunk{
+		LinesInHunk:          1,
+		FinalCommitId:        commitId1,
+		FinalStartLineNumber: 1,
+		OrigCommitId:         commitId1,
+		OrigPath:             "README",
+		OrigStartLineNumber:  1,
+		Boundary:             true,
+	}
+	wantHunk2 := BlameHunk{
+		LinesInHunk:          2,
+		FinalCommitId:        commitId2,
+		FinalStartLineNumber: 2,
+		OrigCommitId:         commitId2,
+		OrigPath:             "README",
+		OrigStartLineNumber:  2,
+		Boundary:             false,
+	}
+
+	hunk1, err := blame.HunkByIndex(0)
+	checkFatal(t, err)
+	checkHunk(t, "index 0", hunk1, wantHunk1)
+
+	hunk2, err := blame.HunkByIndex(1)
+	checkFatal(t, err)
+	checkHunk(t, "index 1", hunk2, wantHunk2)
+
+	hunkLine1, err := blame.HunkByLine(1)
+	checkFatal(t, err)
+	checkHunk(t, "line 1", hunkLine1, wantHunk1)
+
+	hunkLine2, err := blame.HunkByLine(3)
+	checkFatal(t, err)
+	checkHunk(t, "line 2", hunkLine2, wantHunk2)
+}
+
+func checkHunk(t *testing.T, label string, hunk, want BlameHunk) {
+	hunk.FinalSignature = nil
+	want.FinalSignature = nil
+	hunk.OrigSignature = nil
+	want.OrigSignature = nil
+	if !reflect.DeepEqual(hunk, want) {
+		t.Fatalf("%s: got hunk %+v, want %+v", label, hunk, want)
+	}
+}

blob.go

@@ -1,26 +1,151 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
+#include <string.h>
+
+int _go_git_writestream_write(git_writestream *stream, const char *buffer, size_t len);
+void _go_git_writestream_free(git_writestream *stream);
 */
 import "C"
 import (
+	"reflect"
+	"runtime"
 	"unsafe"
 )
 
 type Blob struct {
-	gitObject
+	doNotCompare
+	Object
+	cast_ptr *C.git_blob
 }
 
-func (v Blob) Size() int64 {
-	return int64(C.git_blob_rawsize(v.ptr))
+func (b *Blob) AsObject() *Object {
+	return &b.Object
 }
 
-func (v Blob) Contents() []byte {
-	size := C.int(C.git_blob_rawsize(v.ptr))
-	buffer := unsafe.Pointer(C.git_blob_rawcontent(v.ptr))
-	return C.GoBytes(buffer, size)
+func (v *Blob) Size() int64 {
+	ret := int64(C.git_blob_rawsize(v.cast_ptr))
+	runtime.KeepAlive(v)
+	return ret
 }
 
+func (v *Blob) Contents() []byte {
+	size := C.int(C.git_blob_rawsize(v.cast_ptr))
+	buffer := unsafe.Pointer(C.git_blob_rawcontent(v.cast_ptr))
+
+	goBytes := C.GoBytes(buffer, size)
+	runtime.KeepAlive(v)
+
+	return goBytes
+}
+
+func (v *Blob) IsBinary() bool {
+	ret := C.git_blob_is_binary(v.cast_ptr) == 1
+	runtime.KeepAlive(v)
+	return ret
+}
+
+func (repo *Repository) CreateBlobFromBuffer(data []byte) (*Oid, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var id C.git_oid
+	var size C.size_t
+
+	// Go 1.6 added some increased checking of passing pointer to
+	// C, but its check depends on its expectations of what we
+	// pass to the C function, so unless we take the address of
+	// its contents at the call site itself, it can fail when
+	// 'data' is a slice of a slice.
+	//
+	// When we're given an empty slice, create a dummy one where 0
+	// isn't out of bounds.
+	if len(data) > 0 {
+		size = C.size_t(len(data))
+	} else {
+		data = []byte{0}
+		size = C.size_t(0)
+	}
+
+	ecode := C.git_blob_create_from_buffer(&id, repo.ptr, unsafe.Pointer(&data[0]), size)
+	runtime.KeepAlive(repo)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+	return newOidFromC(&id), nil
+}
+
+func (repo *Repository) CreateFromStream(hintPath string) (*BlobWriteStream, error) {
+	var chintPath *C.char = nil
+	var stream *C.git_writestream
+
+	if len(hintPath) > 0 {
+		chintPath = C.CString(hintPath)
+		defer C.free(unsafe.Pointer(chintPath))
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_blob_create_from_stream(&stream, repo.ptr, chintPath)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newBlobWriteStreamFromC(stream, repo), nil
+}
+
+type BlobWriteStream struct {
+	doNotCompare
+	ptr  *C.git_writestream
+	repo *Repository
+}
+
+func newBlobWriteStreamFromC(ptr *C.git_writestream, repo *Repository) *BlobWriteStream {
+	stream := &BlobWriteStream{
+		ptr:  ptr,
+		repo: repo,
+	}
+
+	runtime.SetFinalizer(stream, (*BlobWriteStream).Free)
+	return stream
+}
+
+// Implement io.Writer
+func (stream *BlobWriteStream) Write(p []byte) (int, error) {
+	header := (*reflect.SliceHeader)(unsafe.Pointer(&p))
+	ptr := (*C.char)(unsafe.Pointer(header.Data))
+	size := C.size_t(header.Len)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C._go_git_writestream_write(stream.ptr, ptr, size)
+	runtime.KeepAlive(stream)
+	if ecode < 0 {
+		return 0, MakeGitError(ecode)
+	}
+
+	return len(p), nil
+}
+
+func (stream *BlobWriteStream) Free() {
+	runtime.SetFinalizer(stream, nil)
+	C._go_git_writestream_free(stream.ptr)
+}
+
+func (stream *BlobWriteStream) Commit() (*Oid, error) {
+	oid := C.git_oid{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_blob_create_from_stream_commit(&oid, stream.ptr)
+	runtime.KeepAlive(stream)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newOidFromC(&oid), nil
+}

blob_test.go

@@ -0,0 +1,60 @@
+package git
+
+import (
+	"bytes"
+	"testing"
+)
+
+type bufWrapper struct {
+	buf     [64]byte
+	pointer []byte
+}
+
+func doublePointerBytes() []byte {
+	o := &bufWrapper{}
+	o.pointer = o.buf[0:10]
+	return o.pointer[0:1]
+}
+
+func TestCreateBlobFromBuffer(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	id, err := repo.CreateBlobFromBuffer(make([]byte, 0))
+	checkFatal(t, err)
+
+	if id.String() != "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391" {
+		t.Fatal("Empty buffer did not deliver empty blob id")
+	}
+
+	tests := []struct {
+		data     []byte
+		isBinary bool
+	}{
+		{
+			data:     []byte("hello there"),
+			isBinary: false,
+		},
+		{
+			data:     doublePointerBytes(),
+			isBinary: true,
+		},
+	}
+	for _, tt := range tests {
+		data := tt.data
+		id, err = repo.CreateBlobFromBuffer(data)
+		checkFatal(t, err)
+
+		blob, err := repo.LookupBlob(id)
+		checkFatal(t, err)
+		if !bytes.Equal(blob.Contents(), data) {
+			t.Fatal("Loaded bytes don't match original bytes:",
+				blob.Contents(), "!=", data)
+		}
+		want := tt.isBinary
+		if got := blob.IsBinary(); got != want {
+			t.Fatalf("IsBinary() = %v, want %v", got, want)
+		}
+	}
+}

branch.go

@@ -0,0 +1,264 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+
+import (
+	"runtime"
+	"unsafe"
+)
+
+type BranchType uint
+
+const (
+	BranchAll    BranchType = C.GIT_BRANCH_ALL
+	BranchLocal  BranchType = C.GIT_BRANCH_LOCAL
+	BranchRemote BranchType = C.GIT_BRANCH_REMOTE
+)
+
+type Branch struct {
+	doNotCompare
+	*Reference
+}
+
+func (r *Reference) Branch() *Branch {
+	return &Branch{Reference: r}
+}
+
+type BranchIterator struct {
+	doNotCompare
+	ptr  *C.git_branch_iterator
+	repo *Repository
+}
+
+type BranchIteratorFunc func(*Branch, BranchType) error
+
+func newBranchIteratorFromC(repo *Repository, ptr *C.git_branch_iterator) *BranchIterator {
+	i := &BranchIterator{repo: repo, ptr: ptr}
+	runtime.SetFinalizer(i, (*BranchIterator).Free)
+	return i
+}
+
+func (i *BranchIterator) Next() (*Branch, BranchType, error) {
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var refPtr *C.git_reference
+	var refType C.git_branch_t
+
+	ecode := C.git_branch_next(&refPtr, &refType, i.ptr)
+
+	if ecode < 0 {
+		return nil, BranchLocal, MakeGitError(ecode)
+	}
+
+	branch := newReferenceFromC(refPtr, i.repo).Branch()
+
+	return branch, BranchType(refType), nil
+}
+
+func (i *BranchIterator) Free() {
+	runtime.SetFinalizer(i, nil)
+	C.git_branch_iterator_free(i.ptr)
+}
+
+func (i *BranchIterator) ForEach(f BranchIteratorFunc) error {
+	b, t, err := i.Next()
+
+	for err == nil {
+		err = f(b, t)
+		if err == nil {
+			b, t, err = i.Next()
+		}
+	}
+
+	if err != nil && IsErrorCode(err, ErrorCodeIterOver) {
+		return nil
+	}
+
+	return err
+}
+
+func (repo *Repository) NewBranchIterator(flags BranchType) (*BranchIterator, error) {
+	refType := C.git_branch_t(flags)
+	var ptr *C.git_branch_iterator
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_branch_iterator_new(&ptr, repo.ptr, refType)
+	runtime.KeepAlive(repo)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newBranchIteratorFromC(repo, ptr), nil
+}
+
+func (repo *Repository) CreateBranch(branchName string, target *Commit, force bool) (*Branch, error) {
+
+	var ptr *C.git_reference
+	cBranchName := C.CString(branchName)
+	defer C.free(unsafe.Pointer(cBranchName))
+	cForce := cbool(force)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_branch_create(&ptr, repo.ptr, cBranchName, target.cast_ptr, cForce)
+	runtime.KeepAlive(repo)
+	runtime.KeepAlive(target)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return newReferenceFromC(ptr, repo).Branch(), nil
+}
+
+func (b *Branch) Delete() error {
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+	ret := C.git_branch_delete(b.Reference.ptr)
+	runtime.KeepAlive(b.Reference)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (b *Branch) Move(newBranchName string, force bool) (*Branch, error) {
+	var ptr *C.git_reference
+	cNewBranchName := C.CString(newBranchName)
+	defer C.free(unsafe.Pointer(cNewBranchName))
+	cForce := cbool(force)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_branch_move(&ptr, b.Reference.ptr, cNewBranchName, cForce)
+	runtime.KeepAlive(b.Reference)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return newReferenceFromC(ptr, b.repo).Branch(), nil
+}
+
+func (b *Branch) IsHead() (bool, error) {
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_branch_is_head(b.Reference.ptr)
+	runtime.KeepAlive(b.Reference)
+	switch ret {
+	case 1:
+		return true, nil
+	case 0:
+		return false, nil
+	}
+	return false, MakeGitError(ret)
+
+}
+
+func (repo *Repository) LookupBranch(branchName string, bt BranchType) (*Branch, error) {
+	var ptr *C.git_reference
+
+	cName := C.CString(branchName)
+	defer C.free(unsafe.Pointer(cName))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_branch_lookup(&ptr, repo.ptr, cName, C.git_branch_t(bt))
+	runtime.KeepAlive(repo)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return newReferenceFromC(ptr, repo).Branch(), nil
+}
+
+func (b *Branch) Name() (string, error) {
+	var cName *C.char
+	defer C.free(unsafe.Pointer(cName))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_branch_name(&cName, b.Reference.ptr)
+	runtime.KeepAlive(b.Reference)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+
+	return C.GoString(cName), nil
+}
+
+func (repo *Repository) RemoteName(canonicalBranchName string) (string, error) {
+	cName := C.CString(canonicalBranchName)
+	defer C.free(unsafe.Pointer(cName))
+
+	nameBuf := C.git_buf{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_branch_remote_name(&nameBuf, repo.ptr, cName)
+	runtime.KeepAlive(repo)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+	defer C.git_buf_dispose(&nameBuf)
+
+	return C.GoString(nameBuf.ptr), nil
+}
+
+func (b *Branch) SetUpstream(upstreamName string) error {
+	cName := C.CString(upstreamName)
+	defer C.free(unsafe.Pointer(cName))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_branch_set_upstream(b.Reference.ptr, cName)
+	runtime.KeepAlive(b.Reference)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (b *Branch) Upstream() (*Reference, error) {
+
+	var ptr *C.git_reference
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_branch_upstream(&ptr, b.Reference.ptr)
+	runtime.KeepAlive(b.Reference)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return newReferenceFromC(ptr, b.repo), nil
+}
+
+func (repo *Repository) UpstreamName(canonicalBranchName string) (string, error) {
+	cName := C.CString(canonicalBranchName)
+	defer C.free(unsafe.Pointer(cName))
+
+	nameBuf := C.git_buf{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_branch_upstream_name(&nameBuf, repo.ptr, cName)
+	runtime.KeepAlive(repo)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+	defer C.git_buf_dispose(&nameBuf)
+
+	return C.GoString(nameBuf.ptr), nil
+}

branch_test.go

@@ -0,0 +1,63 @@
+package git
+
+import (
+	"testing"
+)
+
+func TestBranchIterator(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	i, err := repo.NewBranchIterator(BranchLocal)
+	checkFatal(t, err)
+
+	b, bt, err := i.Next()
+	checkFatal(t, err)
+	if name, _ := b.Name(); name != "master" {
+		t.Fatalf("expected master")
+	} else if bt != BranchLocal {
+		t.Fatalf("expected BranchLocal, not %v", t)
+	}
+	b, bt, err = i.Next()
+	if !IsErrorCode(err, ErrorCodeIterOver) {
+		t.Fatal("expected iterover")
+	}
+}
+
+func TestBranchIteratorEach(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	i, err := repo.NewBranchIterator(BranchLocal)
+	checkFatal(t, err)
+
+	var names []string
+	f := func(b *Branch, t BranchType) error {
+		name, err := b.Name()
+		if err != nil {
+			return err
+		}
+
+		names = append(names, name)
+		return nil
+	}
+
+	err = i.ForEach(f)
+	if err != nil && !IsErrorCode(err, ErrorCodeIterOver) {
+		t.Fatal(err)
+	}
+
+	if len(names) != 1 {
+		t.Fatalf("expect 1 branch, but it was %d\n", len(names))
+	}
+
+	if names[0] != "master" {
+		t.Fatalf("expect branch master, but it was %s\n", names[0])
+	}
+}

checkout.go

@@ -1,81 +1,266 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-git_checkout_opts git_checkout_opts_init() {
-	git_checkout_opts ret = GIT_CHECKOUT_OPTS_INIT;
-	return ret;
-}
+
+extern void _go_git_populate_checkout_callbacks(git_checkout_options *opts);
 */
 import "C"
 import (
 	"os"
+	"runtime"
+	"unsafe"
 )
 
+type CheckoutNotifyType uint
 type CheckoutStrategy uint
 
 const (
+	CheckoutNotifyNone      CheckoutNotifyType = C.GIT_CHECKOUT_NOTIFY_NONE
+	CheckoutNotifyConflict  CheckoutNotifyType = C.GIT_CHECKOUT_NOTIFY_CONFLICT
+	CheckoutNotifyDirty     CheckoutNotifyType = C.GIT_CHECKOUT_NOTIFY_DIRTY
+	CheckoutNotifyUpdated   CheckoutNotifyType = C.GIT_CHECKOUT_NOTIFY_UPDATED
+	CheckoutNotifyUntracked CheckoutNotifyType = C.GIT_CHECKOUT_NOTIFY_UNTRACKED
+	CheckoutNotifyIgnored   CheckoutNotifyType = C.GIT_CHECKOUT_NOTIFY_IGNORED
+	CheckoutNotifyAll       CheckoutNotifyType = C.GIT_CHECKOUT_NOTIFY_ALL
+
 	CheckoutNone                      CheckoutStrategy = C.GIT_CHECKOUT_NONE                         // Dry run, no actual updates
-	CheckoutSafe                                       = C.GIT_CHECKOUT_SAFE                         // Allow safe updates that cannot overwrite uncommitted data
-	CheckoutSafeCreate                                 = C.GIT_CHECKOUT_SAFE_CREATE                  // Allow safe updates plus creation of missing files
-	CheckoutForce                                      = C.GIT_CHECKOUT_FORCE                        // Allow all updates to force working directory to look like index
-	CheckoutAllowConflicts                             = C.GIT_CHECKOUT_ALLOW_CONFLICTS              // Allow checkout to make safe updates even if conflicts are found
-	CheckoutRemoveUntracked                            = C.GIT_CHECKOUT_REMOVE_UNTRACKED             // Remove untracked files not in index (that are not ignored)
-	CheckoutRemoveIgnored                              = C.GIT_CHECKOUT_REMOVE_IGNORED               // Remove ignored files not in index
-	CheckotUpdateOnly                                  = C.GIT_CHECKOUT_UPDATE_ONLY                  // Only update existing files, don't create new ones
-	CheckoutDontUpdateIndex                            = C.GIT_CHECKOUT_DONT_UPDATE_INDEX            // Normally checkout updates index entries as it goes; this stops that
-	CheckoutNoRefresh                                  = C.GIT_CHECKOUT_NO_REFRESH                   // Don't refresh index/config/etc before doing checkout
-	CheckooutDisablePathspecMatch                      = C.GIT_CHECKOUT_DISABLE_PATHSPEC_MATCH       // Treat pathspec as simple list of exact match file paths
-	CheckoutSkipUnmerged                               = C.GIT_CHECKOUT_SKIP_UNMERGED                // Allow checkout to skip unmerged files (NOT IMPLEMENTED)
-	CheckoutUserOurs                                   = C.GIT_CHECKOUT_USE_OURS                     // For unmerged files, checkout stage 2 from index (NOT IMPLEMENTED)
-	CheckoutUseTheirs                                  = C.GIT_CHECKOUT_USE_THEIRS                   // For unmerged files, checkout stage 3 from index (NOT IMPLEMENTED)
-	CheckoutUpdateSubmodules                           = C.GIT_CHECKOUT_UPDATE_SUBMODULES            // Recursively checkout submodules with same options (NOT IMPLEMENTED)
-	CheckoutUpdateSubmodulesIfChanged                  = C.GIT_CHECKOUT_UPDATE_SUBMODULES_IF_CHANGED // Recursively checkout submodules if HEAD moved in super repo (NOT IMPLEMENTED)
+	CheckoutSafe                      CheckoutStrategy = C.GIT_CHECKOUT_SAFE                         // Allow safe updates that cannot overwrite uncommitted data
+	CheckoutForce                     CheckoutStrategy = C.GIT_CHECKOUT_FORCE                        // Allow all updates to force working directory to look like index
+	CheckoutRecreateMissing           CheckoutStrategy = C.GIT_CHECKOUT_RECREATE_MISSING             // Allow checkout to recreate missing files
+	CheckoutAllowConflicts            CheckoutStrategy = C.GIT_CHECKOUT_ALLOW_CONFLICTS              // Allow checkout to make safe updates even if conflicts are found
+	CheckoutRemoveUntracked           CheckoutStrategy = C.GIT_CHECKOUT_REMOVE_UNTRACKED             // Remove untracked files not in index (that are not ignored)
+	CheckoutRemoveIgnored             CheckoutStrategy = C.GIT_CHECKOUT_REMOVE_IGNORED               // Remove ignored files not in index
+	CheckoutUpdateOnly                CheckoutStrategy = C.GIT_CHECKOUT_UPDATE_ONLY                  // Only update existing files, don't create new ones
+	CheckoutDontUpdateIndex           CheckoutStrategy = C.GIT_CHECKOUT_DONT_UPDATE_INDEX            // Normally checkout updates index entries as it goes; this stops that
+	CheckoutNoRefresh                 CheckoutStrategy = C.GIT_CHECKOUT_NO_REFRESH                   // Don't refresh index/config/etc before doing checkout
+	CheckoutSkipUnmerged              CheckoutStrategy = C.GIT_CHECKOUT_SKIP_UNMERGED                // Allow checkout to skip unmerged files
+	CheckoutUseOurs                   CheckoutStrategy = C.GIT_CHECKOUT_USE_OURS                     // For unmerged files, checkout stage 2 from index
+	CheckoutUseTheirs                 CheckoutStrategy = C.GIT_CHECKOUT_USE_THEIRS                   // For unmerged files, checkout stage 3 from index
+	CheckoutDisablePathspecMatch      CheckoutStrategy = C.GIT_CHECKOUT_DISABLE_PATHSPEC_MATCH       // Treat pathspec as simple list of exact match file paths
+	CheckoutSkipLockedDirectories     CheckoutStrategy = C.GIT_CHECKOUT_SKIP_LOCKED_DIRECTORIES      // Ignore directories in use, they will be left empty
+	CheckoutDontOverwriteIgnored      CheckoutStrategy = C.GIT_CHECKOUT_DONT_OVERWRITE_IGNORED       // Don't overwrite ignored files that exist in the checkout target
+	CheckoutConflictStyleMerge        CheckoutStrategy = C.GIT_CHECKOUT_CONFLICT_STYLE_MERGE         // Write normal merge files for conflicts
+	CheckoutConflictStyleDiff3        CheckoutStrategy = C.GIT_CHECKOUT_CONFLICT_STYLE_DIFF3         // Include common ancestor data in diff3 format files for conflicts
+	CheckoutDontRemoveExisting        CheckoutStrategy = C.GIT_CHECKOUT_DONT_REMOVE_EXISTING         // Don't overwrite existing files or folders
+	CheckoutDontWriteIndex            CheckoutStrategy = C.GIT_CHECKOUT_DONT_WRITE_INDEX             // Normally checkout writes the index upon completion; this prevents that
+	CheckoutUpdateSubmodules          CheckoutStrategy = C.GIT_CHECKOUT_UPDATE_SUBMODULES            // Recursively checkout submodules with same options (NOT IMPLEMENTED)
+	CheckoutUpdateSubmodulesIfChanged CheckoutStrategy = C.GIT_CHECKOUT_UPDATE_SUBMODULES_IF_CHANGED // Recursively checkout submodules if HEAD moved in super repo (NOT IMPLEMENTED)
 )
 
-type CheckoutOpts struct {
-	Strategy       CheckoutStrategy // Default will be a dry run
-	DisableFilters bool				// Don't apply filters like CRLF conversion
-	DirMode        os.FileMode		// Default is 0755
-	FileMode       os.FileMode		// Default is 0644 or 0755 as dictated by blob
-	FileOpenFlags  int				// Default is O_CREAT | O_TRUNC | O_WRONLY
+type CheckoutNotifyCallback func(why CheckoutNotifyType, path string, baseline, target, workdir DiffFile) error
+type CheckoutProgressCallback func(path string, completed, total uint)
+
+type CheckoutOptions struct {
+	Strategy         CheckoutStrategy   // Default will be a dry run
+	DisableFilters   bool               // Don't apply filters like CRLF conversion
+	DirMode          os.FileMode        // Default is 0755
+	FileMode         os.FileMode        // Default is 0644 or 0755 as dictated by blob
+	FileOpenFlags    int                // Default is O_CREAT | O_TRUNC | O_WRONLY
+	NotifyFlags      CheckoutNotifyType // Default will be none
+	NotifyCallback   CheckoutNotifyCallback
+	ProgressCallback CheckoutProgressCallback
+	TargetDirectory  string // Alternative checkout path to workdir
+	Paths            []string
+	Baseline         *Tree
 }
 
-// Convert the CheckoutOpts struct to the corresponding C-struct
-func populateCheckoutOpts(ptr *C.git_checkout_opts, opts *CheckoutOpts) {
-	*ptr = C.git_checkout_opts_init()
-	if opts == nil {
+func checkoutOptionsFromC(c *C.git_checkout_options) CheckoutOptions {
+	opts := CheckoutOptions{
+		Strategy:       CheckoutStrategy(c.checkout_strategy),
+		DisableFilters: c.disable_filters != 0,
+		DirMode:        os.FileMode(c.dir_mode),
+		FileMode:       os.FileMode(c.file_mode),
+		FileOpenFlags:  int(c.file_open_flags),
+		NotifyFlags:    CheckoutNotifyType(c.notify_flags),
+	}
+	if c.notify_payload != nil {
+		opts.NotifyCallback = pointerHandles.Get(c.notify_payload).(*checkoutCallbackData).options.NotifyCallback
+	}
+	if c.progress_payload != nil {
+		opts.ProgressCallback = pointerHandles.Get(c.progress_payload).(*checkoutCallbackData).options.ProgressCallback
+	}
+	if c.target_directory != nil {
+		opts.TargetDirectory = C.GoString(c.target_directory)
+	}
+	return opts
+}
+
+type checkoutCallbackData struct {
+	options     *CheckoutOptions
+	errorTarget *error
+}
+
+//export checkoutNotifyCallback
+func checkoutNotifyCallback(
+	why C.git_checkout_notify_t,
+	cpath *C.char,
+	cbaseline, ctarget, cworkdir, handle unsafe.Pointer,
+) C.int {
+	if handle == nil {
+		return C.int(ErrorCodeOK)
+	}
+	path := C.GoString(cpath)
+	var baseline, target, workdir DiffFile
+	if cbaseline != nil {
+		baseline = diffFileFromC((*C.git_diff_file)(cbaseline))
+	}
+	if ctarget != nil {
+		target = diffFileFromC((*C.git_diff_file)(ctarget))
+	}
+	if cworkdir != nil {
+		workdir = diffFileFromC((*C.git_diff_file)(cworkdir))
+	}
+	data := pointerHandles.Get(handle).(*checkoutCallbackData)
+	if data.options.NotifyCallback == nil {
+		return C.int(ErrorCodeOK)
+	}
+	err := data.options.NotifyCallback(CheckoutNotifyType(why), path, baseline, target, workdir)
+	if err != nil {
+		*data.errorTarget = err
+		return C.int(ErrorCodeUser)
+	}
+	return C.int(ErrorCodeOK)
+}
+
+//export checkoutProgressCallback
+func checkoutProgressCallback(
+	path *C.char,
+	completed_steps, total_steps C.size_t,
+	handle unsafe.Pointer,
+) {
+	data := pointerHandles.Get(handle).(*checkoutCallbackData)
+	if data.options.ProgressCallback == nil {
 		return
 	}
-	ptr.checkout_strategy = C.uint(opts.Strategy)
-	ptr.disable_filters = cbool(opts.DisableFilters)
-	ptr.dir_mode = C.uint(opts.DirMode.Perm())
-	ptr.file_mode = C.uint(opts.FileMode.Perm())
+	data.options.ProgressCallback(C.GoString(path), uint(completed_steps), uint(total_steps))
+}
+
+// populateCheckoutOptions populates the provided C-struct with the contents of
+// the provided CheckoutOptions struct.  Returns copts, or nil if opts is nil,
+// in order to help with what to pass.
+func populateCheckoutOptions(copts *C.git_checkout_options, opts *CheckoutOptions, errorTarget *error) *C.git_checkout_options {
+	C.git_checkout_options_init(copts, C.GIT_CHECKOUT_OPTIONS_VERSION)
+	if opts == nil {
+		return nil
+	}
+
+	copts.checkout_strategy = C.uint(opts.Strategy)
+	copts.disable_filters = cbool(opts.DisableFilters)
+	copts.dir_mode = C.uint(opts.DirMode.Perm())
+	copts.file_mode = C.uint(opts.FileMode.Perm())
+	copts.notify_flags = C.uint(opts.NotifyFlags)
+	if opts.NotifyCallback != nil || opts.ProgressCallback != nil {
+		C._go_git_populate_checkout_callbacks(copts)
+		data := &checkoutCallbackData{
+			options:     opts,
+			errorTarget: errorTarget,
+		}
+		payload := pointerHandles.Track(data)
+		if opts.NotifyCallback != nil {
+			copts.notify_payload = payload
+		}
+		if opts.ProgressCallback != nil {
+			copts.progress_payload = payload
+		}
+	}
+	if opts.TargetDirectory != "" {
+		copts.target_directory = C.CString(opts.TargetDirectory)
+	}
+	if len(opts.Paths) > 0 {
+		copts.paths.strings = makeCStringsFromStrings(opts.Paths)
+		copts.paths.count = C.size_t(len(opts.Paths))
+	}
+
+	if opts.Baseline != nil {
+		copts.baseline = opts.Baseline.cast_ptr
+	}
+
+	return copts
+}
+
+func freeCheckoutOptions(copts *C.git_checkout_options) {
+	if copts == nil {
+		return
+	}
+	C.free(unsafe.Pointer(copts.target_directory))
+	if copts.paths.count > 0 {
+		freeStrarray(&copts.paths)
+	}
+	if copts.notify_payload != nil {
+		pointerHandles.Untrack(copts.notify_payload)
+	} else if copts.progress_payload != nil {
+		pointerHandles.Untrack(copts.progress_payload)
+	}
 }
 
 // Updates files in the index and the working tree to match the content of
-// the commit pointed at by HEAD.
-func (v *Repository) Checkout(opts *CheckoutOpts) error {
-	var copts C.git_checkout_opts
-	populateCheckoutOpts(&copts, opts)
+// the commit pointed at by HEAD. opts may be nil.
+func (v *Repository) CheckoutHead(opts *CheckoutOptions) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
 
-	ret := C.git_checkout_head(v.ptr, &copts)
+	var err error
+	cOpts := populateCheckoutOptions(&C.git_checkout_options{}, opts, &err)
+	defer freeCheckoutOptions(cOpts)
+
+	ret := C.git_checkout_head(v.ptr, cOpts)
+	runtime.KeepAlive(v)
+
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 
 	return nil
 }
 
-// Updates files in the working tree to match the content of the index.
-func (v *Repository) CheckoutIndex(index *Index, opts *CheckoutOpts) error {
-	var copts C.git_checkout_opts
-	populateCheckoutOpts(&copts, opts)
+// Updates files in the working tree to match the content of the given
+// index. If index is nil, the repository's index will be used. opts
+// may be nil.
+func (v *Repository) CheckoutIndex(index *Index, opts *CheckoutOptions) error {
+	var iptr *C.git_index = nil
+	if index != nil {
+		iptr = index.ptr
+	}
 
-	ret := C.git_checkout_index(v.ptr, index.ptr, &copts)
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var err error
+	cOpts := populateCheckoutOptions(&C.git_checkout_options{}, opts, &err)
+	defer freeCheckoutOptions(cOpts)
+
+	ret := C.git_checkout_index(v.ptr, iptr, cOpts)
+	runtime.KeepAlive(v)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (v *Repository) CheckoutTree(tree *Tree, opts *CheckoutOptions) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var err error
+	cOpts := populateCheckoutOptions(&C.git_checkout_options{}, opts, &err)
+	defer freeCheckoutOptions(cOpts)
+
+	ret := C.git_checkout_tree(v.ptr, tree.ptr, cOpts)
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(tree)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
 	}
 
 	return nil

cherrypick.go

@@ -0,0 +1,94 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+)
+
+type CherrypickOptions struct {
+	Mainline        uint
+	MergeOptions    MergeOptions
+	CheckoutOptions CheckoutOptions
+}
+
+func cherrypickOptionsFromC(c *C.git_cherrypick_options) CherrypickOptions {
+	opts := CherrypickOptions{
+		Mainline:        uint(c.mainline),
+		MergeOptions:    mergeOptionsFromC(&c.merge_opts),
+		CheckoutOptions: checkoutOptionsFromC(&c.checkout_opts),
+	}
+	return opts
+}
+
+func populateCherrypickOptions(copts *C.git_cherrypick_options, opts *CherrypickOptions, errorTarget *error) *C.git_cherrypick_options {
+	C.git_cherrypick_options_init(copts, C.GIT_CHERRYPICK_OPTIONS_VERSION)
+	if opts == nil {
+		return nil
+	}
+	copts.mainline = C.uint(opts.Mainline)
+	populateMergeOptions(&copts.merge_opts, &opts.MergeOptions)
+	populateCheckoutOptions(&copts.checkout_opts, &opts.CheckoutOptions, errorTarget)
+	return copts
+}
+
+func freeCherrypickOpts(copts *C.git_cherrypick_options) {
+	if copts == nil {
+		return
+	}
+	freeMergeOptions(&copts.merge_opts)
+	freeCheckoutOptions(&copts.checkout_opts)
+}
+
+func DefaultCherrypickOptions() (CherrypickOptions, error) {
+	c := C.git_cherrypick_options{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_cherrypick_options_init(&c, C.GIT_CHERRYPICK_OPTIONS_VERSION)
+	if ecode < 0 {
+		return CherrypickOptions{}, MakeGitError(ecode)
+	}
+	defer freeCherrypickOpts(&c)
+	return cherrypickOptionsFromC(&c), nil
+}
+
+func (v *Repository) Cherrypick(commit *Commit, opts CherrypickOptions) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var err error
+	cOpts := populateCherrypickOptions(&C.git_cherrypick_options{}, &opts, &err)
+	defer freeCherrypickOpts(cOpts)
+
+	ret := C.git_cherrypick(v.ptr, commit.cast_ptr, cOpts)
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(commit)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (r *Repository) CherrypickCommit(pick, our *Commit, opts CherrypickOptions) (*Index, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cOpts := populateMergeOptions(&C.git_merge_options{}, &opts.MergeOptions)
+	defer freeMergeOptions(cOpts)
+
+	var ptr *C.git_index
+	ret := C.git_cherrypick_commit(&ptr, r.ptr, pick.cast_ptr, our.cast_ptr, C.uint(opts.Mainline), cOpts)
+	runtime.KeepAlive(pick)
+	runtime.KeepAlive(our)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return newIndexFromC(ptr, r), nil
+}

cherrypick_test.go

@@ -0,0 +1,140 @@
+package git
+
+import (
+	"io/ioutil"
+	"testing"
+)
+
+func checkout(t *testing.T, repo *Repository, commit *Commit) {
+	tree, err := commit.Tree()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = repo.CheckoutTree(tree, &CheckoutOptions{Strategy: CheckoutSafe})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = repo.SetHeadDetached(commit.Id())
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+const content = "Herro, Worrd!"
+
+func readReadme(t *testing.T, repo *Repository) string {
+	bytes, err := ioutil.ReadFile(pathInRepo(repo, "README"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	return string(bytes)
+}
+
+func TestCherrypick(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	c1, _ := seedTestRepo(t, repo)
+	c2, _ := updateReadme(t, repo, content)
+
+	commit1, err := repo.LookupCommit(c1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	commit2, err := repo.LookupCommit(c2)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	checkout(t, repo, commit1)
+
+	if readReadme(t, repo) == content {
+		t.Fatalf("README has wrong content after checking out initial commit")
+	}
+
+	opts, err := DefaultCherrypickOptions()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = repo.Cherrypick(commit2, opts)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if readReadme(t, repo) != content {
+		t.Fatalf("README has wrong contents after cherry-picking")
+	}
+
+	state := repo.State()
+	if state != RepositoryStateCherrypick {
+		t.Fatal("Incorrect repository state: ", state)
+	}
+
+	err = repo.StateCleanup()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	state = repo.State()
+	if state != RepositoryStateNone {
+		t.Fatal("Incorrect repository state: ", state)
+	}
+}
+
+func TestCherrypickCommit(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	c1, _ := seedTestRepo(t, repo)
+	c2, _ := updateReadme(t, repo, content)
+
+	commit1, err := repo.LookupCommit(c1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	commit2, err := repo.LookupCommit(c2)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	checkout(t, repo, commit1)
+
+	if got := readReadme(t, repo); got == content {
+		t.Fatalf("README = %q, want %q", got, content)
+	}
+
+	opts, err := DefaultCherrypickOptions()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	idx, err := repo.CherrypickCommit(commit2, commit1, opts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer idx.Free()
+
+	// The file is only updated in the index, not in the working directory.
+	if got := readReadme(t, repo); got == content {
+		t.Errorf("README = %q, want %q", got, content)
+	}
+	if got := repo.State(); got != RepositoryStateNone {
+		t.Errorf("repo.State() = %v, want %v", got, RepositoryStateCherrypick)
+	}
+
+	if got := idx.EntryCount(); got != 1 {
+		t.Fatalf("idx.EntryCount() = %v, want %v", got, 1)
+	}
+	entry, err := idx.EntryByIndex(0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if entry.Path != "README" {
+		t.Errorf("entry.Path = %v, want %v", entry.Path, "README")
+	}
+}

clone.go

@@ -0,0 +1,133 @@
+package git
+
+/*
+#include <git2.h>
+
+extern void _go_git_populate_clone_callbacks(git_clone_options *opts);
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+type RemoteCreateCallback func(repo *Repository, name, url string) (*Remote, error)
+
+type CloneOptions struct {
+	CheckoutOptions      CheckoutOptions
+	FetchOptions         FetchOptions
+	Bare                 bool
+	CheckoutBranch       string
+	RemoteCreateCallback RemoteCreateCallback
+}
+
+func Clone(url string, path string, options *CloneOptions) (*Repository, error) {
+	curl := C.CString(url)
+	defer C.free(unsafe.Pointer(curl))
+
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	var err error
+	cOptions := populateCloneOptions(&C.git_clone_options{}, options, &err)
+	defer freeCloneOptions(cOptions)
+
+	if len(options.CheckoutBranch) != 0 {
+		cOptions.checkout_branch = C.CString(options.CheckoutBranch)
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_repository
+	ret := C.git_clone(&ptr, curl, cpath, cOptions)
+
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return nil, err
+	}
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newRepositoryFromC(ptr), nil
+}
+
+//export remoteCreateCallback
+func remoteCreateCallback(
+	out **C.git_remote,
+	crepo *C.git_repository,
+	cname, curl *C.char,
+	handle unsafe.Pointer,
+) C.int {
+	name := C.GoString(cname)
+	url := C.GoString(curl)
+	repo := newRepositoryFromC(crepo)
+	repo.weak = true
+	defer repo.Free()
+
+	data, ok := pointerHandles.Get(handle).(*cloneCallbackData)
+	if !ok {
+		panic("invalid remote create callback")
+	}
+
+	remote, err := data.options.RemoteCreateCallback(repo, name, url)
+
+	if err != nil {
+		*data.errorTarget = err
+		return C.int(ErrorCodeUser)
+	}
+	if remote == nil {
+		panic("no remote created by callback")
+	}
+
+	*out = remote.ptr
+
+	// clear finalizer as the calling C function will
+	// free the remote itself
+	runtime.SetFinalizer(remote, nil)
+	remote.repo.Remotes.untrackRemote(remote)
+
+	return C.int(ErrorCodeOK)
+}
+
+type cloneCallbackData struct {
+	options     *CloneOptions
+	errorTarget *error
+}
+
+func populateCloneOptions(copts *C.git_clone_options, opts *CloneOptions, errorTarget *error) *C.git_clone_options {
+	C.git_clone_options_init(copts, C.GIT_CLONE_OPTIONS_VERSION)
+	if opts == nil {
+		return nil
+	}
+	populateCheckoutOptions(&copts.checkout_opts, &opts.CheckoutOptions, errorTarget)
+	populateFetchOptions(&copts.fetch_opts, &opts.FetchOptions, errorTarget)
+	copts.bare = cbool(opts.Bare)
+
+	if opts.RemoteCreateCallback != nil {
+		data := &cloneCallbackData{
+			options:     opts,
+			errorTarget: errorTarget,
+		}
+		// Go v1.1 does not allow to assign a C function pointer
+		C._go_git_populate_clone_callbacks(copts)
+		copts.remote_cb_payload = pointerHandles.Track(data)
+	}
+
+	return copts
+}
+
+func freeCloneOptions(copts *C.git_clone_options) {
+	if copts == nil {
+		return
+	}
+
+	freeCheckoutOptions(&copts.checkout_opts)
+	freeFetchOptions(&copts.fetch_opts)
+
+	if copts.remote_cb_payload != nil {
+		pointerHandles.Untrack(copts.remote_cb_payload)
+	}
+
+	C.free(unsafe.Pointer(copts.checkout_branch))
+}

clone_test.go

@@ -0,0 +1,87 @@
+package git
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+const (
+	REMOTENAME = "testremote"
+)
+
+func TestClone(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	path, err := ioutil.TempDir("", "git2go")
+	checkFatal(t, err)
+
+	ref, err := repo.References.Lookup("refs/heads/master")
+	checkFatal(t, err)
+
+	repo2, err := Clone(repo.Path(), path, &CloneOptions{Bare: true})
+	defer cleanupTestRepo(t, repo2)
+
+	checkFatal(t, err)
+
+	ref2, err := repo2.References.Lookup("refs/heads/master")
+	checkFatal(t, err)
+
+	if ref.Cmp(ref2) != 0 {
+		t.Fatal("reference in clone does not match original ref")
+	}
+}
+
+func TestCloneWithCallback(t *testing.T) {
+	t.Parallel()
+	testPayload := 0
+
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	path, err := ioutil.TempDir("", "git2go")
+	checkFatal(t, err)
+
+	opts := CloneOptions{
+		Bare: true,
+		RemoteCreateCallback: func(r *Repository, name, url string) (*Remote, error) {
+			testPayload += 1
+			return r.Remotes.Create(REMOTENAME, url)
+		},
+	}
+
+	repo2, err := Clone(repo.Path(), path, &opts)
+	defer cleanupTestRepo(t, repo2)
+
+	checkFatal(t, err)
+
+	if testPayload != 1 {
+		t.Fatal("Payload's value has not been changed")
+	}
+
+	remote, err := repo2.Remotes.Lookup(REMOTENAME)
+	if err != nil || remote == nil {
+		t.Fatal("Remote was not created properly")
+	}
+	defer remote.Free()
+}
+
+// TestCloneWithExternalHTTPUrl
+func TestCloneWithExternalHTTPUrl(t *testing.T) {
+
+	path, err := ioutil.TempDir("", "git2go")
+	defer os.RemoveAll(path)
+
+	// clone the repo
+	url := "https://github.com/libgit2/TestGitRepository"
+	_, err = Clone(url, path, &CloneOptions{})
+	if err != nil {
+		t.Fatal("cannot clone remote repo via https, error: ", err)
+	}
+}

commit.go

@@ -2,105 +2,228 @@ package git
 
 /*
 #include <git2.h>
-#include <git2/errors.h>
 
 extern int _go_git_treewalk(git_tree *tree, git_treewalk_mode mode, void *ptr);
 */
 import "C"
 
 import (
+	"runtime"
 	"unsafe"
-	"time"
+)
+
+// MessageEncoding is the encoding of commit messages.
+type MessageEncoding string
+
+const (
+	// MessageEncodingUTF8 is the default message encoding.
+	MessageEncodingUTF8 MessageEncoding = "UTF-8"
 )
 
 // Commit
 type Commit struct {
-	gitObject
+	doNotCompare
+	Object
+	cast_ptr *C.git_commit
 }
 
-func (c Commit) Message() string {
-	return C.GoString(C.git_commit_message(c.ptr))
+func (c *Commit) AsObject() *Object {
+	return &c.Object
 }
 
-func (c Commit) Tree() (*Tree, error) {
-	var ptr *C.git_object
+func (c *Commit) Message() string {
+	ret := C.GoString(C.git_commit_message(c.cast_ptr))
+	runtime.KeepAlive(c)
+	return ret
+}
 
-	err := C.git_commit_tree(&ptr, c.ptr)
-	if err < 0 {
-		return nil, LastError()
+func (c *Commit) MessageEncoding() MessageEncoding {
+	ptr := C.git_commit_message_encoding(c.cast_ptr)
+	if ptr == nil {
+		return MessageEncodingUTF8
+	}
+	ret := C.GoString(ptr)
+	runtime.KeepAlive(c)
+	return MessageEncoding(ret)
+}
+
+func (c *Commit) RawMessage() string {
+	ret := C.GoString(C.git_commit_message_raw(c.cast_ptr))
+	runtime.KeepAlive(c)
+	return ret
+}
+
+// RawHeader gets the full raw text of the commit header.
+func (c *Commit) RawHeader() string {
+	ret := C.GoString(C.git_commit_raw_header(c.cast_ptr))
+	runtime.KeepAlive(c)
+	return ret
+}
+
+// ContentToSign returns the content that will be passed to a signing function for this commit
+func (c *Commit) ContentToSign() string {
+	return c.RawHeader() + "\n" + c.RawMessage()
+}
+
+// CommitSigningCallback defines a function type that takes some data to sign and returns (signature, signature_field, error)
+type CommitSigningCallback func(string) (signature, signatureField string, err error)
+
+// CommitCreateCallback defines a function type that is called when another
+// function is going to create commits (for example, Rebase) to allow callers
+// to override the commit creation behavior. For example, users may wish to
+// sign commits by providing this information to Repository.CreateCommitBuffer,
+// signing that buffer, then calling Repository.CreateCommitWithSignature.
+type CommitCreateCallback func(
+	author, committer *Signature,
+	messageEncoding MessageEncoding,
+	message string,
+	tree *Tree,
+	parents ...*Commit,
+) (oid *Oid, err error)
+
+// WithSignatureUsing creates a new signed commit from this one using the given signing callback
+func (c *Commit) WithSignatureUsing(f CommitSigningCallback) (*Oid, error) {
+	signature, signatureField, err := f(c.ContentToSign())
+	if err != nil {
+		return nil, err
 	}
 
-	return allocObject(ptr).(*Tree), nil
+	return c.WithSignature(signature, signatureField)
 }
 
-func (c Commit) TreeId() *Oid {
-	return newOidFromC(C.git_commit_tree_id(c.ptr))
+// WithSignature creates a new signed commit from the given signature and signature field
+func (c *Commit) WithSignature(signature string, signatureField string) (*Oid, error) {
+	return c.Owner().CreateCommitWithSignature(
+		c.ContentToSign(),
+		signature,
+		signatureField,
+	)
 }
 
-func (c Commit) Author() *Signature {
-	ptr := C.git_commit_author(c.ptr)
-	return newSignatureFromC(ptr)
+func (c *Commit) ExtractSignature() (string, string, error) {
+
+	var c_signed C.git_buf
+	defer C.git_buf_dispose(&c_signed)
+
+	var c_signature C.git_buf
+	defer C.git_buf_dispose(&c_signature)
+
+	oid := c.Id()
+	repo := C.git_commit_owner(c.cast_ptr)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+	ret := C.git_commit_extract_signature(&c_signature, &c_signed, repo, oid.toC(), nil)
+	runtime.KeepAlive(oid)
+	if ret < 0 {
+		return "", "", MakeGitError(ret)
+	} else {
+		return C.GoString(c_signature.ptr), C.GoString(c_signed.ptr), nil
+	}
+
 }
 
-func (c Commit) Committer() *Signature {
-	ptr := C.git_commit_committer(c.ptr)
-	return newSignatureFromC(ptr)
+func (c *Commit) Summary() string {
+	ret := C.GoString(C.git_commit_summary(c.cast_ptr))
+	runtime.KeepAlive(c)
+	return ret
+}
+
+func (c *Commit) Tree() (*Tree, error) {
+	var ptr *C.git_tree
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C.git_commit_tree(&ptr, c.cast_ptr)
+	runtime.KeepAlive(c)
+	if err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return allocTree(ptr, c.repo), nil
+}
+
+func (c *Commit) TreeId() *Oid {
+	ret := newOidFromC(C.git_commit_tree_id(c.cast_ptr))
+	runtime.KeepAlive(c)
+	return ret
+}
+
+func (c *Commit) Author() *Signature {
+	cast_ptr := C.git_commit_author(c.cast_ptr)
+	ret := newSignatureFromC(cast_ptr)
+	runtime.KeepAlive(c)
+	return ret
+}
+
+func (c *Commit) Committer() *Signature {
+	cast_ptr := C.git_commit_committer(c.cast_ptr)
+	ret := newSignatureFromC(cast_ptr)
+	runtime.KeepAlive(c)
+	return ret
 }
 
 func (c *Commit) Parent(n uint) *Commit {
-	par := &Commit{}
-	ret := C.git_commit_parent(&par.ptr, c.ptr, C.uint(n))
+	var cobj *C.git_commit
+	ret := C.git_commit_parent(&cobj, c.cast_ptr, C.uint(n))
 	if ret != 0 {
 		return nil
 	}
-	return par
+
+	parent := allocCommit(cobj, c.repo)
+	runtime.KeepAlive(c)
+	return parent
 }
 
 func (c *Commit) ParentId(n uint) *Oid {
-	return newOidFromC(C.git_commit_parent_id(c.ptr, C.uint(n)))
+	ret := newOidFromC(C.git_commit_parent_id(c.cast_ptr, C.uint(n)))
+	runtime.KeepAlive(c)
+	return ret
 }
 
 func (c *Commit) ParentCount() uint {
-	return uint(C.git_commit_parentcount(c.ptr))
+	ret := uint(C.git_commit_parentcount(c.cast_ptr))
+	runtime.KeepAlive(c)
+	return ret
 }
 
-// Signature
-
-type Signature struct {
-	Name  string
-	Email string
-	When  time.Time
-}
-
-func newSignatureFromC(sig *C.git_signature) *Signature {
-	// git stores minutes, go wants seconds
-	loc := time.FixedZone("", int(sig.when.offset)*60)
-	return &Signature{
-		C.GoString(sig.name),
-		C.GoString(sig.email),
-		time.Unix(int64(sig.when.time), 0).In(loc),
-	}
-}
-
-// the offset in mintes, which is what git wants
-func (v *Signature) Offset() int {
-	_, offset := v.When.Zone()
-	return offset/60
-}
-
-func (sig *Signature) toC() (*C.git_signature) {
-	var out *C.git_signature
-
-	name := C.CString(sig.Name)
-	defer C.free(unsafe.Pointer(name))
-
-	email := C.CString(sig.Email)
-	defer C.free(unsafe.Pointer(email))
-
-	ret := C.git_signature_new(&out, name, email, C.git_time_t(sig.When.Unix()), C.int(sig.Offset()))
-	if ret < 0 {
-		return nil
+func (c *Commit) Amend(refname string, author, committer *Signature, message string, tree *Tree) (*Oid, error) {
+	var cref *C.char
+	if refname == "" {
+		cref = nil
+	} else {
+		cref = C.CString(refname)
+		defer C.free(unsafe.Pointer(cref))
 	}
 
-	return out
+	cmsg := C.CString(message)
+	defer C.free(unsafe.Pointer(cmsg))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	authorSig, err := author.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(authorSig)
+
+	committerSig, err := committer.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(committerSig)
+
+	oid := new(Oid)
+
+	cerr := C.git_commit_amend(oid.toC(), c.cast_ptr, cref, authorSig, committerSig, nil, cmsg, tree.cast_ptr)
+	runtime.KeepAlive(oid)
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(tree)
+	if cerr < 0 {
+		return nil, MakeGitError(cerr)
+	}
+
+	return oid, nil
 }

config.go

@@ -1,69 +1,468 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
 */
 import "C"
 import (
+	"runtime"
 	"unsafe"
 )
 
+type ConfigLevel int
+
+const (
+	// System-wide on Windows, for compatibility with portable git
+	ConfigLevelProgramdata ConfigLevel = C.GIT_CONFIG_LEVEL_PROGRAMDATA
+
+	// System-wide configuration file; /etc/gitconfig on Linux systems
+	ConfigLevelSystem ConfigLevel = C.GIT_CONFIG_LEVEL_SYSTEM
+
+	// XDG compatible configuration file; typically ~/.config/git/config
+	ConfigLevelXDG ConfigLevel = C.GIT_CONFIG_LEVEL_XDG
+
+	// User-specific configuration file (also called Global configuration
+	// file); typically ~/.gitconfig
+	ConfigLevelGlobal ConfigLevel = C.GIT_CONFIG_LEVEL_GLOBAL
+
+	// Repository specific configuration file; $WORK_DIR/.git/config on
+	// non-bare repos
+	ConfigLevelLocal ConfigLevel = C.GIT_CONFIG_LEVEL_LOCAL
+
+	// Application specific configuration file; freely defined by applications
+	ConfigLevelApp ConfigLevel = C.GIT_CONFIG_LEVEL_APP
+
+	// Represents the highest level available config file (i.e. the most
+	// specific config file available that actually is loaded)
+	ConfigLevelHighest ConfigLevel = C.GIT_CONFIG_HIGHEST_LEVEL
+)
+
+type ConfigEntry struct {
+	Name  string
+	Value string
+	Level ConfigLevel
+}
+
+func newConfigEntryFromC(centry *C.git_config_entry) *ConfigEntry {
+	return &ConfigEntry{
+		Name:  C.GoString(centry.name),
+		Value: C.GoString(centry.value),
+		Level: ConfigLevel(centry.level),
+	}
+}
+
 type Config struct {
+	doNotCompare
 	ptr *C.git_config
 }
 
-func (c *Config) LookupInt32(name string) (v int32, err error) {
+// NewConfig creates a new empty configuration object
+func NewConfig() (*Config, error) {
+	config := new(Config)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if ret := C.git_config_new(&config.ptr); ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return config, nil
+}
+
+// AddFile adds a file-backed backend to the config object at the specified level.
+func (c *Config) AddFile(path string, level ConfigLevel, force bool) error {
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_add_file_ondisk(c.ptr, cpath, C.git_config_level_t(level), nil, cbool(force))
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (c *Config) LookupInt32(name string) (int32, error) {
 	var out C.int32_t
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
 
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_config_get_int32(&out, c.ptr, cname)
+	runtime.KeepAlive(c)
 	if ret < 0 {
-		return 0, LastError()
+		return 0, MakeGitError(ret)
 	}
 
 	return int32(out), nil
 }
 
-func (c *Config) LookupInt64(name string) (v int64, err error) {
+func (c *Config) LookupInt64(name string) (int64, error) {
 	var out C.int64_t
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
 
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_config_get_int64(&out, c.ptr, cname)
+	runtime.KeepAlive(c)
 	if ret < 0 {
-		return 0, LastError()
+		return 0, MakeGitError(ret)
 	}
 
 	return int64(out), nil
 }
 
-func (c *Config) LookupString(name string) (v string, err error) {
-	var ptr *C.char
+func (c *Config) LookupString(name string) (string, error) {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
 
-	ret := C.git_config_get_string(&ptr, c.ptr, cname)
-	if ret < 0 {
-		return "", LastError()
-	}
+	valBuf := C.git_buf{}
 
-	return C.GoString(ptr), nil
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_get_string_buf(&valBuf, c.ptr, cname)
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+	defer C.git_buf_dispose(&valBuf)
+
+	return C.GoString(valBuf.ptr), nil
 }
 
-func (c *Config) Set(name, value string) (err error) {
+func (c *Config) LookupBool(name string) (bool, error) {
+	var out C.int
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_get_bool(&out, c.ptr, cname)
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+
+	return out != 0, nil
+}
+
+func (c *Config) NewMultivarIterator(name, regexp string) (*ConfigIterator, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	var cregexp *C.char
+	if regexp == "" {
+		cregexp = nil
+	} else {
+		cregexp = C.CString(regexp)
+		defer C.free(unsafe.Pointer(cregexp))
+	}
+
+	iter := &ConfigIterator{cfg: c}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_multivar_iterator_new(&iter.ptr, c.ptr, cname, cregexp)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	runtime.SetFinalizer(iter, (*ConfigIterator).Free)
+	return iter, nil
+}
+
+// NewIterator creates an iterator over each entry in the
+// configuration
+func (c *Config) NewIterator() (*ConfigIterator, error) {
+	iter := &ConfigIterator{cfg: c}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_iterator_new(&iter.ptr, c.ptr)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return iter, nil
+}
+
+// NewIteratorGlob creates an iterator over each entry in the
+// configuration whose name matches the given regular expression
+func (c *Config) NewIteratorGlob(regexp string) (*ConfigIterator, error) {
+	iter := &ConfigIterator{cfg: c}
+	cregexp := C.CString(regexp)
+	defer C.free(unsafe.Pointer(cregexp))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_iterator_glob_new(&iter.ptr, c.ptr, cregexp)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return iter, nil
+}
+
+func (c *Config) SetString(name, value string) (err error) {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
 
 	cvalue := C.CString(value)
 	defer C.free(unsafe.Pointer(cvalue))
 
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_config_set_string(c.ptr, cname, cvalue)
+	runtime.KeepAlive(c)
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 
 	return nil
 }
+
+func (c *Config) Free() {
+	runtime.SetFinalizer(c, nil)
+	C.git_config_free(c.ptr)
+}
+
+func (c *Config) SetInt32(name string, value int32) (err error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_set_int32(c.ptr, cname, C.int32_t(value))
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (c *Config) SetInt64(name string, value int64) (err error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_set_int64(c.ptr, cname, C.int64_t(value))
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (c *Config) SetBool(name string, value bool) (err error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_set_bool(c.ptr, cname, cbool(value))
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (c *Config) SetMultivar(name, regexp, value string) (err error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	cregexp := C.CString(regexp)
+	defer C.free(unsafe.Pointer(cregexp))
+
+	cvalue := C.CString(value)
+	defer C.free(unsafe.Pointer(cvalue))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_set_multivar(c.ptr, cname, cregexp, cvalue)
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (c *Config) Delete(name string) error {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_delete_entry(c.ptr, cname)
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+// OpenLevel creates a single-level focused config object from a multi-level one
+func (c *Config) OpenLevel(parent *Config, level ConfigLevel) (*Config, error) {
+	config := new(Config)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_open_level(&config.ptr, parent.ptr, C.git_config_level_t(level))
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(parent)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return config, nil
+}
+
+// OpenOndisk creates a new config instance containing a single on-disk file
+func OpenOndisk(path string) (*Config, error) {
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	config := new(Config)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if ret := C.git_config_open_ondisk(&config.ptr, cpath); ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return config, nil
+}
+
+type ConfigIterator struct {
+	doNotCompare
+	ptr *C.git_config_iterator
+	cfg *Config
+}
+
+// Next returns the next entry for this iterator
+func (iter *ConfigIterator) Next() (*ConfigEntry, error) {
+	var centry *C.git_config_entry
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_next(&centry, iter.ptr)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	entry := newConfigEntryFromC(centry)
+	runtime.KeepAlive(iter)
+
+	return entry, nil
+}
+
+func (iter *ConfigIterator) Free() {
+	runtime.SetFinalizer(iter, nil)
+	C.free(unsafe.Pointer(iter.ptr))
+}
+
+func ConfigFindGlobal() (string, error) {
+	var buf C.git_buf
+	defer C.git_buf_dispose(&buf)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_find_global(&buf)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+
+	return C.GoString(buf.ptr), nil
+}
+
+func ConfigFindSystem() (string, error) {
+	var buf C.git_buf
+	defer C.git_buf_dispose(&buf)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_find_system(&buf)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+
+	return C.GoString(buf.ptr), nil
+}
+
+func ConfigFindXDG() (string, error) {
+	var buf C.git_buf
+	defer C.git_buf_dispose(&buf)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_find_xdg(&buf)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+
+	return C.GoString(buf.ptr), nil
+}
+
+// ConfigFindProgramdata locate the path to the configuration file in ProgramData.
+//
+// Look for the file in %PROGRAMDATA%\Git\config used by portable git.
+func ConfigFindProgramdata() (string, error) {
+	var buf C.git_buf
+	defer C.git_buf_dispose(&buf)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_config_find_programdata(&buf)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+
+	return C.GoString(buf.ptr), nil
+}
+
+// OpenDefault opens the default config according to git rules
+func OpenDefault() (*Config, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	config := new(Config)
+
+	if ret := C.git_config_open_default(&config.ptr); ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return config, nil
+}

config_test.go

@@ -0,0 +1,119 @@
+package git
+
+import (
+	"os"
+	"testing"
+)
+
+var tempConfig = "./temp.gitconfig"
+
+func setupConfig() (*Config, error) {
+	var (
+		c   *Config
+		err error
+	)
+
+	c, err = OpenOndisk(tempConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	err = c.SetString("foo.bar", "baz")
+	if err != nil {
+		return nil, err
+	}
+	err = c.SetBool("foo.bool", true)
+	if err != nil {
+		return nil, err
+	}
+	err = c.SetInt32("foo.int32", 32)
+	if err != nil {
+		return nil, err
+	}
+	err = c.SetInt64("foo.int64", 64)
+	if err != nil {
+		return nil, err
+	}
+
+	return c, err
+}
+
+func cleanupConfig() {
+	os.Remove(tempConfig)
+}
+
+type TestRunner func(*Config, *testing.T)
+
+var tests = []TestRunner{
+	// LookupString
+	func(c *Config, t *testing.T) {
+		val, err := c.LookupString("foo.bar")
+		if err != nil {
+			t.Errorf("Got LookupString error: '%v', expected none\n", err)
+		}
+		if val != "baz" {
+			t.Errorf("Got '%s' from LookupString, expected 'bar'\n", val)
+		}
+	},
+	// LookupBool
+	func(c *Config, t *testing.T) {
+		val, err := c.LookupBool("foo.bool")
+		if err != nil {
+			t.Errorf("Got LookupBool error: '%v', expected none\n", err)
+		}
+		if !val {
+			t.Errorf("Got %t from LookupBool, expected 'false'\n", val)
+		}
+	},
+	// LookupInt32
+	func(c *Config, t *testing.T) {
+		val, err := c.LookupInt32("foo.int32")
+		if err != nil {
+			t.Errorf("Got LookupInt32 error: '%v', expected none\n", err)
+		}
+		if val != 32 {
+			t.Errorf("Got %v, expected 32\n", val)
+		}
+	},
+	// LookupInt64
+	func(c *Config, t *testing.T) {
+		val, err := c.LookupInt64("foo.int64")
+		if err != nil {
+			t.Errorf("Got LookupInt64 error: '%v', expected none\n", err)
+		}
+		if val != 64 {
+			t.Errorf("Got %v, expected 64\n", val)
+		}
+	},
+}
+
+func TestConfigLookups(t *testing.T) {
+	t.Parallel()
+	var (
+		err error
+		c   *Config
+	)
+
+	c, err = setupConfig()
+	defer cleanupConfig()
+
+	if err != nil {
+		t.Errorf("Setup error: '%v'. Expected none\n", err)
+		return
+	}
+	defer c.Free()
+
+	for _, test := range tests {
+		test(c, t)
+	}
+}
+
+func TestOpenDefault(t *testing.T) {
+
+	c, err := OpenDefault()
+	if err != nil {
+		t.Errorf("OpenDefault error: '%v'. Expected none\n", err)
+		return
+	}
+	defer c.Free()
+}

credentials.go

@@ -0,0 +1,298 @@
+package git
+
+/*
+#include <git2.h>
+#include <git2/credential.h>
+#include <git2/sys/credential.h>
+
+git_credential_t _go_git_credential_credtype(git_credential *cred);
+void _go_git_populate_credential_ssh_custom(git_credential_ssh_custom *cred);
+*/
+import "C"
+import (
+	"crypto/rand"
+	"errors"
+	"fmt"
+	"runtime"
+	"strings"
+	"unsafe"
+
+	"golang.org/x/crypto/ssh"
+)
+
+// CredentialType is a bitmask of supported credential types.
+//
+// This represents the various types of authentication methods supported by the
+// library.
+type CredentialType uint
+
+const (
+	CredentialTypeUserpassPlaintext CredentialType = C.GIT_CREDENTIAL_USERPASS_PLAINTEXT
+	CredentialTypeSSHKey            CredentialType = C.GIT_CREDENTIAL_SSH_KEY
+	CredentialTypeSSHCustom         CredentialType = C.GIT_CREDENTIAL_SSH_CUSTOM
+	CredentialTypeDefault           CredentialType = C.GIT_CREDENTIAL_DEFAULT
+	CredentialTypeSSHInteractive    CredentialType = C.GIT_CREDENTIAL_SSH_INTERACTIVE
+	CredentialTypeUsername          CredentialType = C.GIT_CREDENTIAL_USERNAME
+	CredentialTypeSSHMemory         CredentialType = C.GIT_CREDENTIAL_SSH_MEMORY
+)
+
+func (t CredentialType) String() string {
+	if t == 0 {
+		return "CredentialType(0)"
+	}
+
+	var parts []string
+
+	if (t & CredentialTypeUserpassPlaintext) != 0 {
+		parts = append(parts, "UserpassPlaintext")
+		t &= ^CredentialTypeUserpassPlaintext
+	}
+	if (t & CredentialTypeSSHKey) != 0 {
+		parts = append(parts, "SSHKey")
+		t &= ^CredentialTypeSSHKey
+	}
+	if (t & CredentialTypeSSHCustom) != 0 {
+		parts = append(parts, "SSHCustom")
+		t &= ^CredentialTypeSSHCustom
+	}
+	if (t & CredentialTypeDefault) != 0 {
+		parts = append(parts, "Default")
+		t &= ^CredentialTypeDefault
+	}
+	if (t & CredentialTypeSSHInteractive) != 0 {
+		parts = append(parts, "SSHInteractive")
+		t &= ^CredentialTypeSSHInteractive
+	}
+	if (t & CredentialTypeUsername) != 0 {
+		parts = append(parts, "Username")
+		t &= ^CredentialTypeUsername
+	}
+	if (t & CredentialTypeSSHMemory) != 0 {
+		parts = append(parts, "SSHMemory")
+		t &= ^CredentialTypeSSHMemory
+	}
+
+	if t != 0 {
+		parts = append(parts, fmt.Sprintf("CredentialType(%#x)", t))
+	}
+
+	return strings.Join(parts, "|")
+}
+
+type Credential struct {
+	doNotCompare
+	ptr *C.git_credential
+}
+
+func newCredential() *Credential {
+	cred := &Credential{}
+	runtime.SetFinalizer(cred, (*Credential).Free)
+	return cred
+}
+
+func (o *Credential) HasUsername() bool {
+	if C.git_credential_has_username(o.ptr) == 1 {
+		return true
+	}
+	return false
+}
+
+func (o *Credential) Type() CredentialType {
+	return (CredentialType)(C._go_git_credential_credtype(o.ptr))
+}
+
+func (o *Credential) Free() {
+	C.git_credential_free(o.ptr)
+	runtime.SetFinalizer(o, nil)
+	o.ptr = nil
+}
+
+// GetUserpassPlaintext returns the plaintext username/password combination stored in the Cred.
+func (o *Credential) GetUserpassPlaintext() (username, password string, err error) {
+	if o.Type() != CredentialTypeUserpassPlaintext {
+		err = errors.New("credential is not userpass plaintext")
+		return
+	}
+
+	plaintextCredPtr := (*C.git_cred_userpass_plaintext)(unsafe.Pointer(o.ptr))
+	username = C.GoString(plaintextCredPtr.username)
+	password = C.GoString(plaintextCredPtr.password)
+	return
+}
+
+// GetSSHKey returns the SSH-specific key information from the Cred object.
+func (o *Credential) GetSSHKey() (username, publickey, privatekey, passphrase string, err error) {
+	if o.Type() != CredentialTypeSSHKey && o.Type() != CredentialTypeSSHMemory {
+		err = fmt.Errorf("credential is not an SSH key: %v", o.Type())
+		return
+	}
+
+	sshKeyCredPtr := (*C.git_cred_ssh_key)(unsafe.Pointer(o.ptr))
+	username = C.GoString(sshKeyCredPtr.username)
+	publickey = C.GoString(sshKeyCredPtr.publickey)
+	privatekey = C.GoString(sshKeyCredPtr.privatekey)
+	passphrase = C.GoString(sshKeyCredPtr.passphrase)
+	return
+}
+
+func NewCredentialUsername(username string) (*Credential, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cred := newCredential()
+	cusername := C.CString(username)
+	ret := C.git_credential_username_new(&cred.ptr, cusername)
+	if ret != 0 {
+		cred.Free()
+		return nil, MakeGitError(ret)
+	}
+	return cred, nil
+}
+
+func NewCredentialUserpassPlaintext(username string, password string) (*Credential, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cred := newCredential()
+	cusername := C.CString(username)
+	defer C.free(unsafe.Pointer(cusername))
+	cpassword := C.CString(password)
+	defer C.free(unsafe.Pointer(cpassword))
+	ret := C.git_credential_userpass_plaintext_new(&cred.ptr, cusername, cpassword)
+	if ret != 0 {
+		cred.Free()
+		return nil, MakeGitError(ret)
+	}
+	return cred, nil
+}
+
+// NewCredentialSSHKey creates new ssh credentials reading the public and private keys
+// from the file system.
+func NewCredentialSSHKey(username string, publicKeyPath string, privateKeyPath string, passphrase string) (*Credential, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cred := newCredential()
+	cusername := C.CString(username)
+	defer C.free(unsafe.Pointer(cusername))
+	cpublickey := C.CString(publicKeyPath)
+	defer C.free(unsafe.Pointer(cpublickey))
+	cprivatekey := C.CString(privateKeyPath)
+	defer C.free(unsafe.Pointer(cprivatekey))
+	cpassphrase := C.CString(passphrase)
+	defer C.free(unsafe.Pointer(cpassphrase))
+	ret := C.git_credential_ssh_key_new(&cred.ptr, cusername, cpublickey, cprivatekey, cpassphrase)
+	if ret != 0 {
+		cred.Free()
+		return nil, MakeGitError(ret)
+	}
+	return cred, nil
+}
+
+// NewCredentialSSHKeyFromMemory creates new ssh credentials using the publicKey and privateKey
+// arguments as the values for the public and private keys.
+func NewCredentialSSHKeyFromMemory(username string, publicKey string, privateKey string, passphrase string) (*Credential, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cred := newCredential()
+	cusername := C.CString(username)
+	defer C.free(unsafe.Pointer(cusername))
+	cpublickey := C.CString(publicKey)
+	defer C.free(unsafe.Pointer(cpublickey))
+	cprivatekey := C.CString(privateKey)
+	defer C.free(unsafe.Pointer(cprivatekey))
+	cpassphrase := C.CString(passphrase)
+	defer C.free(unsafe.Pointer(cpassphrase))
+	ret := C.git_credential_ssh_key_memory_new(&cred.ptr, cusername, cpublickey, cprivatekey, cpassphrase)
+	if ret != 0 {
+		cred.Free()
+		return nil, MakeGitError(ret)
+	}
+	return cred, nil
+}
+
+func NewCredentialSSHKeyFromAgent(username string) (*Credential, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cred := newCredential()
+	cusername := C.CString(username)
+	defer C.free(unsafe.Pointer(cusername))
+	ret := C.git_credential_ssh_key_from_agent(&cred.ptr, cusername)
+	if ret != 0 {
+		cred.Free()
+		return nil, MakeGitError(ret)
+	}
+	return cred, nil
+}
+
+type credentialSSHCustomData struct {
+	signer ssh.Signer
+}
+
+//export credentialSSHCustomFree
+func credentialSSHCustomFree(cred *C.git_credential_ssh_custom) {
+	if cred == nil {
+		return
+	}
+
+	C.free(unsafe.Pointer(cred.username))
+	C.free(unsafe.Pointer(cred.publickey))
+	pointerHandles.Untrack(cred.payload)
+	C.free(unsafe.Pointer(cred))
+}
+
+//export credentialSSHSignCallback
+func credentialSSHSignCallback(
+	errorMessage **C.char,
+	sig **C.uchar,
+	sig_len *C.size_t,
+	data *C.uchar,
+	data_len C.size_t,
+	handle unsafe.Pointer,
+) C.int {
+	signer := pointerHandles.Get(handle).(*credentialSSHCustomData).signer
+	signature, err := signer.Sign(rand.Reader, C.GoBytes(unsafe.Pointer(data), C.int(data_len)))
+	if err != nil {
+		return setCallbackError(errorMessage, err)
+	}
+	*sig = (*C.uchar)(C.CBytes(signature.Blob))
+	*sig_len = C.size_t(len(signature.Blob))
+	return C.int(ErrorCodeOK)
+}
+
+// NewCredentialSSHKeyFromSigner creates new SSH credentials using the provided signer.
+func NewCredentialSSHKeyFromSigner(username string, signer ssh.Signer) (*Credential, error) {
+	publicKey := signer.PublicKey().Marshal()
+
+	ccred := (*C.git_credential_ssh_custom)(C.calloc(1, C.size_t(unsafe.Sizeof(C.git_credential_ssh_custom{}))))
+	ccred.parent.credtype = C.GIT_CREDENTIAL_SSH_CUSTOM
+	ccred.username = C.CString(username)
+	ccred.publickey = (*C.char)(C.CBytes(publicKey))
+	ccred.publickey_len = C.size_t(len(publicKey))
+	C._go_git_populate_credential_ssh_custom(ccred)
+
+	data := credentialSSHCustomData{
+		signer: signer,
+	}
+	ccred.payload = pointerHandles.Track(&data)
+
+	cred := newCredential()
+	cred.ptr = &ccred.parent
+
+	return cred, nil
+}
+
+func NewCredentialDefault() (*Credential, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cred := newCredential()
+	ret := C.git_credential_default_new(&cred.ptr)
+	if ret != 0 {
+		cred.Free()
+		return nil, MakeGitError(ret)
+	}
+	return cred, nil
+}

delta_string.go

@@ -0,0 +1,33 @@
+// Code generated by "stringer -type Delta -trimprefix Delta -tags static"; DO NOT EDIT.
+
+package git
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[DeltaUnmodified-0]
+	_ = x[DeltaAdded-1]
+	_ = x[DeltaDeleted-2]
+	_ = x[DeltaModified-3]
+	_ = x[DeltaRenamed-4]
+	_ = x[DeltaCopied-5]
+	_ = x[DeltaIgnored-6]
+	_ = x[DeltaUntracked-7]
+	_ = x[DeltaTypeChange-8]
+	_ = x[DeltaUnreadable-9]
+	_ = x[DeltaConflicted-10]
+}
+
+const _Delta_name = "UnmodifiedAddedDeletedModifiedRenamedCopiedIgnoredUntrackedTypeChangeUnreadableConflicted"
+
+var _Delta_index = [...]uint8{0, 10, 15, 22, 30, 37, 43, 50, 59, 69, 79, 89}
+
+func (i Delta) String() string {
+	if i < 0 || i >= Delta(len(_Delta_index)-1) {
+		return "Delta(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _Delta_name[_Delta_index[i]:_Delta_index[i+1]]
+}

deprecated.go

@@ -0,0 +1,271 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"unsafe"
+)
+
+// The constants, functions, and types in this files are slated for deprecation
+// in the next major version.
+
+// blob.go
+
+// Deprecated: BlobChunkCallback is not used.
+type BlobChunkCallback func(maxLen int) ([]byte, error)
+
+// Deprecated: BlobCallbackData is not used.
+type BlobCallbackData struct {
+	Callback BlobChunkCallback
+	Error    error
+}
+
+// checkout.go
+
+// Deprecated: CheckoutOpts is a deprecated alias of CheckoutOptions.
+type CheckoutOpts = CheckoutOptions
+
+// credentials.go
+
+// Deprecated: CredType is a deprecated alias of CredentialType
+type CredType = CredentialType
+
+const (
+	CredTypeUserpassPlaintext = CredentialTypeUserpassPlaintext
+	CredTypeSshKey            = CredentialTypeSSHKey
+	CredTypeSshCustom         = CredentialTypeSSHCustom
+	CredTypeDefault           = CredentialTypeDefault
+)
+
+// Deprecated: Cred is a deprecated alias of Credential
+type Cred = Credential
+
+// Deprecated: NewCredUsername is a deprecated alias of NewCredentialUsername.
+func NewCredUsername(username string) (*Cred, error) {
+	return NewCredentialUsername(username)
+}
+
+// Deprecated: NewCredUserpassPlaintext is a deprecated alias of NewCredentialUserpassPlaintext.
+func NewCredUserpassPlaintext(username string, password string) (*Cred, error) {
+	return NewCredentialUserpassPlaintext(username, password)
+}
+
+// Deprecated: NewCredSshKey is a deprecated alias of NewCredentialSshKey.
+func NewCredSshKey(username string, publicKeyPath string, privateKeyPath string, passphrase string) (*Cred, error) {
+	return NewCredentialSSHKey(username, publicKeyPath, privateKeyPath, passphrase)
+}
+
+// Deprecated: NewCredSshKeyFromMemory is a deprecated alias of NewCredentialSSHKeyFromMemory.
+func NewCredSshKeyFromMemory(username string, publicKey string, privateKey string, passphrase string) (*Cred, error) {
+	return NewCredentialSSHKeyFromMemory(username, publicKey, privateKey, passphrase)
+}
+
+// Deprecated: NewCredSshKeyFromAgent is a deprecated alias of NewCredentialSSHFromAgent.
+func NewCredSshKeyFromAgent(username string) (*Cred, error) {
+	return NewCredentialSSHKeyFromAgent(username)
+}
+
+// Deprecated: NewCredDefault is a deprecated alias fof NewCredentialDefault.
+func NewCredDefault() (*Cred, error) {
+	return NewCredentialDefault()
+}
+
+// diff.go
+
+const (
+	// Deprecated: DiffIgnoreWhitespaceEol is a deprecated alias of DiffIgnoreWhitespaceEOL.
+	DiffIgnoreWitespaceEol = DiffIgnoreWhitespaceEOL
+)
+
+// features.go
+
+const (
+	// Deprecated: FeatureHttps is a deprecated alias of FeatureHTTPS.
+	FeatureHttps = FeatureHTTPS
+
+	// Deprecated: FeatureSsh is a deprecated alias of FeatureSSH.
+	FeatureSsh = FeatureSSH
+)
+
+// git.go
+
+const (
+	// Deprecated: ErrClassNone is a deprecated alias of ErrorClassNone.
+	ErrClassNone = ErrorClassNone
+	// Deprecated: ErrClassNoMemory is a deprecated alias of ErrorClassNoMemory.
+	ErrClassNoMemory = ErrorClassNoMemory
+	// Deprecated: ErrClassOs is a deprecated alias of ErrorClassOS.
+	ErrClassOs = ErrorClassOS
+	// Deprecated: ErrClassInvalid is a deprecated alias of ErrorClassInvalid.
+	ErrClassInvalid = ErrorClassInvalid
+	// Deprecated: ErrClassReference is a deprecated alias of ErrorClassReference.
+	ErrClassReference = ErrorClassReference
+	// Deprecated: ErrClassZlib is a deprecated alias of ErrorClassZlib.
+	ErrClassZlib = ErrorClassZlib
+	// Deprecated: ErrClassRepository is a deprecated alias of ErrorClassRepository.
+	ErrClassRepository = ErrorClassRepository
+	// Deprecated: ErrClassConfig is a deprecated alias of ErrorClassConfig.
+	ErrClassConfig = ErrorClassConfig
+	// Deprecated: ErrClassRegex is a deprecated alias of ErrorClassRegex.
+	ErrClassRegex = ErrorClassRegex
+	// Deprecated: ErrClassOdb is a deprecated alias of ErrorClassOdb.
+	ErrClassOdb = ErrorClassOdb
+	// Deprecated: ErrClassIndex is a deprecated alias of ErrorClassIndex.
+	ErrClassIndex = ErrorClassIndex
+	// Deprecated: ErrClassObject is a deprecated alias of ErrorClassObject.
+	ErrClassObject = ErrorClassObject
+	// Deprecated: ErrClassNet is a deprecated alias of ErrorClassNet.
+	ErrClassNet = ErrorClassNet
+	// Deprecated: ErrClassTag is a deprecated alias of ErrorClassTag.
+	ErrClassTag = ErrorClassTag
+	// Deprecated: ErrClassTree is a deprecated alias of ErrorClassTree.
+	ErrClassTree = ErrorClassTree
+	// Deprecated: ErrClassIndexer is a deprecated alias of ErrorClassIndexer.
+	ErrClassIndexer = ErrorClassIndexer
+	// Deprecated: ErrClassSSL is a deprecated alias of ErrorClassSSL.
+	ErrClassSSL = ErrorClassSSL
+	// Deprecated: ErrClassSubmodule is a deprecated alias of ErrorClassSubmodule.
+	ErrClassSubmodule = ErrorClassSubmodule
+	// Deprecated: ErrClassThread is a deprecated alias of ErrorClassThread.
+	ErrClassThread = ErrorClassThread
+	// Deprecated: ErrClassStash is a deprecated alias of ErrorClassStash.
+	ErrClassStash = ErrorClassStash
+	// Deprecated: ErrClassCheckout is a deprecated alias of ErrorClassCheckout.
+	ErrClassCheckout = ErrorClassCheckout
+	// Deprecated: ErrClassFetchHead is a deprecated alias of ErrorClassFetchHead.
+	ErrClassFetchHead = ErrorClassFetchHead
+	// Deprecated: ErrClassMerge is a deprecated alias of ErrorClassMerge.
+	ErrClassMerge = ErrorClassMerge
+	// Deprecated: ErrClassSsh is a deprecated alias of ErrorClassSSH.
+	ErrClassSsh = ErrorClassSSH
+	// Deprecated: ErrClassFilter is a deprecated alias of ErrorClassFilter.
+	ErrClassFilter = ErrorClassFilter
+	// Deprecated: ErrClassRevert is a deprecated alias of ErrorClassRevert.
+	ErrClassRevert = ErrorClassRevert
+	// Deprecated: ErrClassCallback is a deprecated alias of ErrorClassCallback.
+	ErrClassCallback = ErrorClassCallback
+	// Deprecated: ErrClassRebase is a deprecated alias of ErrorClassRebase.
+	ErrClassRebase = ErrorClassRebase
+	// Deprecated: ErrClassPatch is a deprecated alias of ErrorClassPatch.
+	ErrClassPatch = ErrorClassPatch
+)
+
+const (
+	// Deprecated: ErrOk is a deprecated alias of ErrorCodeOK.
+	ErrOk = ErrorCodeOK
+	// Deprecated: ErrGeneric is a deprecated alias of ErrorCodeGeneric.
+	ErrGeneric = ErrorCodeGeneric
+	// Deprecated: ErrNotFound is a deprecated alias of ErrorCodeNotFound.
+	ErrNotFound = ErrorCodeNotFound
+	// Deprecated: ErrExists is a deprecated alias of ErrorCodeExists.
+	ErrExists = ErrorCodeExists
+	// Deprecated: ErrAmbiguous is a deprecated alias of ErrorCodeAmbiguous.
+	ErrAmbiguous = ErrorCodeAmbiguous
+	// Deprecated: ErrAmbigious is a deprecated alias of ErrorCodeAmbiguous.
+	ErrAmbigious = ErrorCodeAmbiguous
+	// Deprecated: ErrBuffs is a deprecated alias of ErrorCodeBuffs.
+	ErrBuffs = ErrorCodeBuffs
+	// Deprecated: ErrUser is a deprecated alias of ErrorCodeUser.
+	ErrUser = ErrorCodeUser
+	// Deprecated: ErrBareRepo is a deprecated alias of ErrorCodeBareRepo.
+	ErrBareRepo = ErrorCodeBareRepo
+	// Deprecated: ErrUnbornBranch is a deprecated alias of ErrorCodeUnbornBranch.
+	ErrUnbornBranch = ErrorCodeUnbornBranch
+	// Deprecated: ErrUnmerged is a deprecated alias of ErrorCodeUnmerged.
+	ErrUnmerged = ErrorCodeUnmerged
+	// Deprecated: ErrNonFastForward is a deprecated alias of ErrorCodeNonFastForward.
+	ErrNonFastForward = ErrorCodeNonFastForward
+	// Deprecated: ErrInvalidSpec is a deprecated alias of ErrorCodeInvalidSpec.
+	ErrInvalidSpec = ErrorCodeInvalidSpec
+	// Deprecated: ErrConflict is a deprecated alias of ErrorCodeConflict.
+	ErrConflict = ErrorCodeConflict
+	// Deprecated: ErrLocked is a deprecated alias of ErrorCodeLocked.
+	ErrLocked = ErrorCodeLocked
+	// Deprecated: ErrModified is a deprecated alias of ErrorCodeModified.
+	ErrModified = ErrorCodeModified
+	// Deprecated: ErrAuth is a deprecated alias of ErrorCodeAuth.
+	ErrAuth = ErrorCodeAuth
+	// Deprecated: ErrCertificate is a deprecated alias of ErrorCodeCertificate.
+	ErrCertificate = ErrorCodeCertificate
+	// Deprecated: ErrApplied is a deprecated alias of ErrorCodeApplied.
+	ErrApplied = ErrorCodeApplied
+	// Deprecated: ErrPeel is a deprecated alias of ErrorCodePeel.
+	ErrPeel = ErrorCodePeel
+	// Deprecated: ErrEOF is a deprecated alias of ErrorCodeEOF.
+	ErrEOF = ErrorCodeEOF
+	// Deprecated: ErrUncommitted is a deprecated alias of ErrorCodeUncommitted.
+	ErrUncommitted = ErrorCodeUncommitted
+	// Deprecated: ErrDirectory is a deprecated alias of ErrorCodeDirectory.
+	ErrDirectory = ErrorCodeDirectory
+	// Deprecated: ErrMergeConflict is a deprecated alias of ErrorCodeMergeConflict.
+	ErrMergeConflict = ErrorCodeMergeConflict
+	// Deprecated: ErrPassthrough is a deprecated alias of ErrorCodePassthrough.
+	ErrPassthrough = ErrorCodePassthrough
+	// Deprecated: ErrIterOver is a deprecated alias of ErrorCodeIterOver.
+	ErrIterOver = ErrorCodeIterOver
+	// Deprecated: ErrApplyFail is a deprecated alias of ErrorCodeApplyFail.
+	ErrApplyFail = ErrorCodeApplyFail
+)
+
+// index.go
+
+// Deprecated: IndexAddOpts is a deprecated alias of IndexAddOption.
+type IndexAddOpts = IndexAddOption
+
+// Deprecated: IndexStageOpts is a deprecated alias of IndexStageState.
+type IndexStageOpts = IndexStageState
+
+// submodule.go
+
+// Deprecated: SubmoduleCbk is a deprecated alias of SubmoduleCallback.
+type SubmoduleCbk = SubmoduleCallback
+
+// Deprecated: SubmoduleVisitor is not used.
+func SubmoduleVisitor(csub unsafe.Pointer, name *C.char, handle unsafe.Pointer) C.int {
+	sub := &Submodule{ptr: (*C.git_submodule)(csub)}
+
+	callback, ok := pointerHandles.Get(handle).(SubmoduleCallback)
+	if !ok {
+		panic("invalid submodule visitor callback")
+	}
+	err := callback(sub, C.GoString(name))
+	if err != nil {
+		return C.int(ErrorCodeUser)
+	}
+	return C.int(ErrorCodeOK)
+}
+
+// reference.go
+
+// Deprecated: ReferenceIsValidName is a deprecated alias of ReferenceNameIsValid.
+func ReferenceIsValidName(name string) bool {
+	valid, _ := ReferenceNameIsValid(name)
+	return valid
+}
+
+// remote.go
+
+// Deprecated: RemoteIsValidName is a deprecated alias of RemoteNameIsValid.
+func RemoteIsValidName(name string) bool {
+	valid, _ := RemoteNameIsValid(name)
+	return valid
+}
+
+// tree.go
+
+// Deprecated: CallbackGitTreeWalk is not used.
+func CallbackGitTreeWalk(_root *C.char, entry *C.git_tree_entry, ptr unsafe.Pointer) C.int {
+	root := C.GoString(_root)
+
+	callback, ok := pointerHandles.Get(ptr).(TreeWalkCallback)
+	if !ok {
+		panic("invalid treewalk callback")
+	}
+	err := callback(root, newTreeEntry(entry))
+	if err != nil {
+		return C.int(ErrorCodeUser)
+	}
+	return C.int(ErrorCodeOK)
+}

describe.go

@@ -0,0 +1,226 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+// DescribeOptions represents the describe operation configuration.
+//
+// You can use DefaultDescribeOptions() to get default options.
+type DescribeOptions struct {
+	// How many tags as candidates to consider to describe the input commit-ish.
+	// Increasing it above 10 will take slightly longer but may produce a more
+	// accurate result. 0 will cause only exact matches to be output.
+	MaxCandidatesTags uint // default: 10
+
+	// By default describe only shows annotated tags. Change this in order
+	// to show all refs from refs/tags or refs/.
+	Strategy DescribeOptionsStrategy // default: DescribeDefault
+
+	// Only consider tags matching the given glob(7) pattern, excluding
+	// the "refs/tags/" prefix. Can be used to avoid leaking private
+	// tags from the repo.
+	Pattern string
+
+	// When calculating the distance from the matching tag or
+	// reference, only walk down the first-parent ancestry.
+	OnlyFollowFirstParent bool
+
+	// If no matching tag or reference is found, the describe
+	// operation would normally fail. If this option is set, it
+	// will instead fall back to showing the full id of the commit.
+	ShowCommitOidAsFallback bool
+}
+
+// DefaultDescribeOptions returns default options for the describe operation.
+func DefaultDescribeOptions() (DescribeOptions, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	opts := C.git_describe_options{}
+	ecode := C.git_describe_options_init(&opts, C.GIT_DESCRIBE_OPTIONS_VERSION)
+	if ecode < 0 {
+		return DescribeOptions{}, MakeGitError(ecode)
+	}
+
+	return DescribeOptions{
+		MaxCandidatesTags: uint(opts.max_candidates_tags),
+		Strategy:          DescribeOptionsStrategy(opts.describe_strategy),
+	}, nil
+}
+
+// DescribeFormatOptions can be used for formatting the describe string.
+//
+// You can use DefaultDescribeFormatOptions() to get default options.
+type DescribeFormatOptions struct {
+	// Size of the abbreviated commit id to use. This value is the
+	// lower bound for the length of the abbreviated string.
+	AbbreviatedSize uint // default: 7
+
+	// Set to use the long format even when a shorter name could be used.
+	AlwaysUseLongFormat bool
+
+	// If the workdir is dirty and this is set, this string will be
+	// appended to the description string.
+	DirtySuffix string
+}
+
+// DefaultDescribeFormatOptions returns default options for formatting
+// the output.
+func DefaultDescribeFormatOptions() (DescribeFormatOptions, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	opts := C.git_describe_format_options{}
+	ecode := C.git_describe_format_options_init(&opts, C.GIT_DESCRIBE_FORMAT_OPTIONS_VERSION)
+	if ecode < 0 {
+		return DescribeFormatOptions{}, MakeGitError(ecode)
+	}
+
+	return DescribeFormatOptions{
+		AbbreviatedSize:     uint(opts.abbreviated_size),
+		AlwaysUseLongFormat: opts.always_use_long_format == 1,
+	}, nil
+}
+
+// DescribeOptionsStrategy behaves like the --tags and --all options
+// to git-describe, namely they say to look for any reference in
+// either refs/tags/ or refs/ respectively.
+//
+// By default it only shows annotated tags.
+type DescribeOptionsStrategy uint
+
+// Describe strategy options.
+const (
+	DescribeDefault DescribeOptionsStrategy = C.GIT_DESCRIBE_DEFAULT
+	DescribeTags    DescribeOptionsStrategy = C.GIT_DESCRIBE_TAGS
+	DescribeAll     DescribeOptionsStrategy = C.GIT_DESCRIBE_ALL
+)
+
+// Describe performs the describe operation on the commit.
+func (c *Commit) Describe(opts *DescribeOptions) (*DescribeResult, error) {
+	var resultPtr *C.git_describe_result
+
+	var cDescribeOpts *C.git_describe_options
+	if opts != nil {
+		var cpattern *C.char
+		if len(opts.Pattern) > 0 {
+			cpattern = C.CString(opts.Pattern)
+			defer C.free(unsafe.Pointer(cpattern))
+		}
+
+		cDescribeOpts = &C.git_describe_options{
+			version:                     C.GIT_DESCRIBE_OPTIONS_VERSION,
+			max_candidates_tags:         C.uint(opts.MaxCandidatesTags),
+			describe_strategy:           C.uint(opts.Strategy),
+			pattern:                     cpattern,
+			only_follow_first_parent:    cbool(opts.OnlyFollowFirstParent),
+			show_commit_oid_as_fallback: cbool(opts.ShowCommitOidAsFallback),
+		}
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_describe_commit(&resultPtr, c.ptr, cDescribeOpts)
+	runtime.KeepAlive(c)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newDescribeResultFromC(resultPtr), nil
+}
+
+// DescribeWorkdir describes the working tree. It means describe HEAD
+// and appends <mark> (-dirty by default) if the working tree is dirty.
+func (repo *Repository) DescribeWorkdir(opts *DescribeOptions) (*DescribeResult, error) {
+	var resultPtr *C.git_describe_result
+
+	var cDescribeOpts *C.git_describe_options
+	if opts != nil {
+		var cpattern *C.char
+		if len(opts.Pattern) > 0 {
+			cpattern = C.CString(opts.Pattern)
+			defer C.free(unsafe.Pointer(cpattern))
+		}
+
+		cDescribeOpts = &C.git_describe_options{
+			version:                     C.GIT_DESCRIBE_OPTIONS_VERSION,
+			max_candidates_tags:         C.uint(opts.MaxCandidatesTags),
+			describe_strategy:           C.uint(opts.Strategy),
+			pattern:                     cpattern,
+			only_follow_first_parent:    cbool(opts.OnlyFollowFirstParent),
+			show_commit_oid_as_fallback: cbool(opts.ShowCommitOidAsFallback),
+		}
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_describe_workdir(&resultPtr, repo.ptr, cDescribeOpts)
+	runtime.KeepAlive(repo)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newDescribeResultFromC(resultPtr), nil
+}
+
+// DescribeResult represents the output from the 'git_describe_commit'
+// and 'git_describe_workdir' functions in libgit2.
+//
+// Use Format() to get a string out of it.
+type DescribeResult struct {
+	doNotCompare
+	ptr *C.git_describe_result
+}
+
+func newDescribeResultFromC(ptr *C.git_describe_result) *DescribeResult {
+	result := &DescribeResult{
+		ptr: ptr,
+	}
+	runtime.SetFinalizer(result, (*DescribeResult).Free)
+	return result
+}
+
+// Format prints the DescribeResult as a string.
+func (result *DescribeResult) Format(opts *DescribeFormatOptions) (string, error) {
+	resultBuf := C.git_buf{}
+
+	var cFormatOpts *C.git_describe_format_options
+	if opts != nil {
+		cDirtySuffix := C.CString(opts.DirtySuffix)
+		defer C.free(unsafe.Pointer(cDirtySuffix))
+
+		cFormatOpts = &C.git_describe_format_options{
+			version:                C.GIT_DESCRIBE_FORMAT_OPTIONS_VERSION,
+			abbreviated_size:       C.uint(opts.AbbreviatedSize),
+			always_use_long_format: cbool(opts.AlwaysUseLongFormat),
+			dirty_suffix:           cDirtySuffix,
+		}
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_describe_format(&resultBuf, result.ptr, cFormatOpts)
+	runtime.KeepAlive(result)
+	if ecode < 0 {
+		return "", MakeGitError(ecode)
+	}
+	defer C.git_buf_dispose(&resultBuf)
+
+	return C.GoString(resultBuf.ptr), nil
+}
+
+// Free cleans up the C reference.
+func (result *DescribeResult) Free() {
+	runtime.SetFinalizer(result, nil)
+	C.git_describe_result_free(result.ptr)
+	result.ptr = nil
+}

describe_test.go

@@ -0,0 +1,109 @@
+package git
+
+import (
+	"path"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestDescribeCommit(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	describeOpts, err := DefaultDescribeOptions()
+	checkFatal(t, err)
+
+	formatOpts, err := DefaultDescribeFormatOptions()
+	checkFatal(t, err)
+
+	commitID, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	// No annotated tags can be used to describe master
+	_, err = commit.Describe(&describeOpts)
+	checkDescribeNoRefsFound(t, err)
+
+	// Fallback
+	fallback := describeOpts
+	fallback.ShowCommitOidAsFallback = true
+	result, err := commit.Describe(&fallback)
+	checkFatal(t, err)
+	resultStr, err := result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "473bf77", resultStr)
+
+	// Abbreviated
+	abbreviated := formatOpts
+	abbreviated.AbbreviatedSize = 2
+	result, err = commit.Describe(&fallback)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&abbreviated)
+	checkFatal(t, err)
+	compareStrings(t, "473b", resultStr)
+
+	createTestTag(t, repo, commit)
+
+	// Exact tag
+	patternOpts := describeOpts
+	patternOpts.Pattern = "v[0-9]*"
+	result, err = commit.Describe(&patternOpts)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "v0.0.0", resultStr)
+
+	// Pattern no match
+	patternOpts.Pattern = "v[1-9]*"
+	result, err = commit.Describe(&patternOpts)
+	checkDescribeNoRefsFound(t, err)
+
+	commitID, _ = updateReadme(t, repo, "update1")
+	commit, err = repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	// Tag-1
+	result, err = commit.Describe(&describeOpts)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "v0.0.0-1-gd88ef8d", resultStr)
+
+	// Strategy: All
+	describeOpts.Strategy = DescribeAll
+	result, err = commit.Describe(&describeOpts)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "heads/master", resultStr)
+
+	repo.CreateBranch("hotfix", commit, false)
+
+	// Workdir (branch)
+	result, err = repo.DescribeWorkdir(&describeOpts)
+	checkFatal(t, err)
+	resultStr, err = result.Format(&formatOpts)
+	checkFatal(t, err)
+	compareStrings(t, "heads/hotfix", resultStr)
+}
+
+func checkDescribeNoRefsFound(t *testing.T, err error) {
+	// The failure happens at wherever we were called, not here
+	_, file, line, ok := runtime.Caller(1)
+	expectedString := "no reference found, cannot describe anything"
+	if !ok {
+		t.Fatalf("Unable to get caller")
+	}
+	if err == nil || !strings.Contains(err.Error(), expectedString) {
+		t.Fatalf(
+			"%s:%v: was expecting error %v, got %v",
+			path.Base(file),
+			line,
+			expectedString,
+			err,
+		)
+	}
+}

diff_test.go

@@ -0,0 +1,685 @@
+package git
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"path"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestFindSimilar(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	originalTree, newTree := createTestTrees(t, repo)
+
+	diffOpt, _ := DefaultDiffOptions()
+
+	diff, err := repo.DiffTreeToTree(originalTree, newTree, &diffOpt)
+	checkFatal(t, err)
+	if diff == nil {
+		t.Fatal("no diff returned")
+	}
+
+	findOpts, err := DefaultDiffFindOptions()
+	checkFatal(t, err)
+	findOpts.Flags = DiffFindBreakRewrites
+
+	err = diff.FindSimilar(&findOpts)
+	checkFatal(t, err)
+
+	numDiffs := 0
+	numAdded := 0
+	numDeleted := 0
+
+	err = diff.ForEach(func(file DiffDelta, progress float64) (DiffForEachHunkCallback, error) {
+		numDiffs++
+
+		switch file.Status {
+		case DeltaAdded:
+			numAdded++
+		case DeltaDeleted:
+			numDeleted++
+		}
+
+		return func(hunk DiffHunk) (DiffForEachLineCallback, error) {
+			return func(line DiffLine) error {
+				return nil
+			}, nil
+		}, nil
+	}, DiffDetailLines)
+
+	if numDiffs != 2 {
+		t.Fatal("Incorrect number of files in diff")
+	}
+	if numAdded != 1 {
+		t.Fatal("Incorrect number of new files in diff")
+	}
+	if numDeleted != 1 {
+		t.Fatal("Incorrect number of deleted files in diff")
+	}
+
+}
+
+func TestDiffTreeToTree(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	originalTree, newTree := createTestTrees(t, repo)
+
+	callbackInvoked := false
+	opts := DiffOptions{
+		NotifyCallback: func(diffSoFar *Diff, delta DiffDelta, matchedPathSpec string) error {
+			callbackInvoked = true
+			return nil
+		},
+		OldPrefix: "x1/",
+		NewPrefix: "y1/",
+	}
+
+	diff, err := repo.DiffTreeToTree(originalTree, newTree, &opts)
+	checkFatal(t, err)
+	if !callbackInvoked {
+		t.Fatal("callback not invoked")
+	}
+
+	if diff == nil {
+		t.Fatal("no diff returned")
+	}
+
+	files := make([]string, 0)
+	hunks := make([]DiffHunk, 0)
+	lines := make([]DiffLine, 0)
+	patches := make([]string, 0)
+	err = diff.ForEach(func(file DiffDelta, progress float64) (DiffForEachHunkCallback, error) {
+		patch, err := diff.Patch(len(patches))
+		if err != nil {
+			return nil, err
+		}
+		defer patch.Free()
+		patchStr, err := patch.String()
+		if err != nil {
+			return nil, err
+		}
+		patches = append(patches, patchStr)
+
+		files = append(files, file.OldFile.Path)
+		return func(hunk DiffHunk) (DiffForEachLineCallback, error) {
+			hunks = append(hunks, hunk)
+			return func(line DiffLine) error {
+				lines = append(lines, line)
+				return nil
+			}, nil
+		}, nil
+	}, DiffDetailLines)
+
+	checkFatal(t, err)
+
+	if len(files) != 1 {
+		t.Fatal("Incorrect number of files in diff")
+	}
+
+	if files[0] != "README" {
+		t.Fatal("File in diff was expected to be README")
+	}
+
+	if len(hunks) != 1 {
+		t.Fatal("Incorrect number of hunks in diff")
+	}
+
+	if hunks[0].OldStart != 1 || hunks[0].NewStart != 1 {
+		t.Fatal("Incorrect hunk")
+	}
+
+	if len(lines) != 2 {
+		t.Fatal("Incorrect number of lines in diff")
+	}
+
+	if lines[0].Content != "foo\n" {
+		t.Fatal("Incorrect lines in diff")
+	}
+
+	if lines[1].Content != "file changed\n" {
+		t.Fatal("Incorrect lines in diff")
+	}
+
+	if want1, want2 := "x1/README", "y1/README"; !strings.Contains(patches[0], want1) || !strings.Contains(patches[0], want2) {
+		t.Errorf("Diff patch doesn't contain %q or %q\n\n%s", want1, want2, patches[0])
+
+	}
+
+	stats, err := diff.Stats()
+	checkFatal(t, err)
+
+	if stats.Insertions() != 1 {
+		t.Fatal("Incorrect number of insertions in diff")
+	}
+	if stats.Deletions() != 1 {
+		t.Fatal("Incorrect number of deletions in diff")
+	}
+	if stats.FilesChanged() != 1 {
+		t.Fatal("Incorrect number of changed files in diff")
+	}
+
+	errTest := errors.New("test error")
+
+	err = diff.ForEach(func(file DiffDelta, progress float64) (DiffForEachHunkCallback, error) {
+		return nil, errTest
+	}, DiffDetailLines)
+
+	if err != errTest {
+		t.Fatalf("Expected custom error to be returned, got %v, want %v", err, errTest)
+	}
+}
+
+func createTestTrees(t *testing.T, repo *Repository) (originalTree *Tree, newTree *Tree) {
+	var err error
+	_, originalTreeId := seedTestRepo(t, repo)
+	originalTree, err = repo.LookupTree(originalTreeId)
+
+	checkFatal(t, err)
+
+	_, newTreeId := updateReadme(t, repo, "file changed\n")
+
+	newTree, err = repo.LookupTree(newTreeId)
+	checkFatal(t, err)
+
+	return originalTree, newTree
+}
+
+func TestDiffBlobs(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	odb, err := repo.Odb()
+	checkFatal(t, err)
+
+	id1, err := odb.Write([]byte("hello\nhello\n"), ObjectBlob)
+	checkFatal(t, err)
+
+	id2, err := odb.Write([]byte("hallo\nhallo\n"), ObjectBlob)
+	checkFatal(t, err)
+
+	blob1, err := repo.LookupBlob(id1)
+	checkFatal(t, err)
+
+	blob2, err := repo.LookupBlob(id2)
+	checkFatal(t, err)
+
+	var files, hunks, lines int
+	err = DiffBlobs(blob1, "hi", blob2, "hi", nil,
+		func(delta DiffDelta, progress float64) (DiffForEachHunkCallback, error) {
+			files++
+			return func(hunk DiffHunk) (DiffForEachLineCallback, error) {
+				hunks++
+				return func(line DiffLine) error {
+					lines++
+					return nil
+				}, nil
+			}, nil
+		},
+		DiffDetailLines)
+
+	if files != 1 {
+		t.Fatal("Bad number of files iterated")
+	}
+
+	if hunks != 1 {
+		t.Fatal("Bad number of hunks iterated")
+	}
+
+	// two removals, two additions
+	if lines != 4 {
+		t.Fatalf("Bad number of lines iterated")
+	}
+}
+
+func TestApplyDiffAddfile(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	addFirstFileCommit, addFirstFileTree := addAndGetTree(t, repo, "file1", `hello`)
+	defer addFirstFileCommit.Free()
+	defer addFirstFileTree.Free()
+	addSecondFileCommit, addSecondFileTree := addAndGetTree(t, repo, "file2", `hello2`)
+	defer addSecondFileCommit.Free()
+	defer addSecondFileTree.Free()
+
+	diff, err := repo.DiffTreeToTree(addFirstFileTree, addSecondFileTree, nil)
+	checkFatal(t, err)
+	defer diff.Free()
+
+	t.Run("check does not apply to current tree because file exists", func(t *testing.T) {
+		err = repo.ResetToCommit(addSecondFileCommit, ResetHard, &CheckoutOptions{})
+		checkFatal(t, err)
+
+		err = repo.ApplyDiff(diff, ApplyLocationBoth, nil)
+		if err == nil {
+			t.Error("expecting applying patch to current repo to fail")
+		}
+	})
+
+	t.Run("check apply to correct commit", func(t *testing.T) {
+		err = repo.ResetToCommit(addFirstFileCommit, ResetHard, &CheckoutOptions{})
+		checkFatal(t, err)
+
+		err = repo.ApplyDiff(diff, ApplyLocationBoth, nil)
+		checkFatal(t, err)
+
+		t.Run("Check that diff only changed one file", func(t *testing.T) {
+			checkSecondFileStaged(t, repo)
+
+			index, err := repo.Index()
+			checkFatal(t, err)
+			defer index.Free()
+
+			newTreeOID, err := index.WriteTreeTo(repo)
+			checkFatal(t, err)
+
+			newTree, err := repo.LookupTree(newTreeOID)
+			checkFatal(t, err)
+			defer newTree.Free()
+
+			_, err = repo.CreateCommit("HEAD", signature(), signature(), fmt.Sprintf("patch apply"), newTree, addFirstFileCommit)
+			checkFatal(t, err)
+		})
+
+		t.Run("test applying patch produced the same diff", func(t *testing.T) {
+			head, err := repo.Head()
+			checkFatal(t, err)
+
+			commit, err := repo.LookupCommit(head.Target())
+			checkFatal(t, err)
+			defer commit.Free()
+
+			tree, err := commit.Tree()
+			checkFatal(t, err)
+			defer tree.Free()
+
+			newDiff, err := repo.DiffTreeToTree(addFirstFileTree, tree, nil)
+			checkFatal(t, err)
+			defer newDiff.Free()
+
+			raw1b, err := diff.ToBuf(DiffFormatPatch)
+			checkFatal(t, err)
+			raw2b, err := newDiff.ToBuf(DiffFormatPatch)
+			checkFatal(t, err)
+
+			raw1 := string(raw1b)
+			raw2 := string(raw2b)
+
+			if raw1 != raw2 {
+				t.Error("diffs should be the same")
+			}
+		})
+	})
+
+	t.Run("check convert to raw buffer and apply", func(t *testing.T) {
+		err = repo.ResetToCommit(addFirstFileCommit, ResetHard, &CheckoutOptions{})
+		checkFatal(t, err)
+
+		raw, err := diff.ToBuf(DiffFormatPatch)
+		checkFatal(t, err)
+
+		if len(raw) == 0 {
+			t.Error("empty diff created")
+		}
+
+		diff2, err := DiffFromBuffer(raw, repo)
+		checkFatal(t, err)
+		defer diff2.Free()
+
+		err = repo.ApplyDiff(diff2, ApplyLocationBoth, nil)
+		checkFatal(t, err)
+	})
+
+	t.Run("check apply callbacks work", func(t *testing.T) {
+		// reset the state and get new default options for test
+		resetAndGetOpts := func(t *testing.T) *ApplyOptions {
+			err = repo.ResetToCommit(addFirstFileCommit, ResetHard, &CheckoutOptions{})
+			checkFatal(t, err)
+
+			opts, err := DefaultApplyOptions()
+			checkFatal(t, err)
+
+			return opts
+		}
+
+		t.Run("Check hunk callback working applies patch", func(t *testing.T) {
+			opts := resetAndGetOpts(t)
+
+			called := false
+			opts.ApplyHunkCallback = func(hunk *DiffHunk) (apply bool, err error) {
+				called = true
+				return true, nil
+			}
+
+			err = repo.ApplyDiff(diff, ApplyLocationBoth, opts)
+			checkFatal(t, err)
+
+			if called == false {
+				t.Error("apply hunk callback was not called")
+			}
+
+			checkSecondFileStaged(t, repo)
+		})
+
+		t.Run("Check delta callback working applies patch", func(t *testing.T) {
+			opts := resetAndGetOpts(t)
+
+			called := false
+			opts.ApplyDeltaCallback = func(hunk *DiffDelta) (apply bool, err error) {
+				if hunk.NewFile.Path != "file2" {
+					t.Error("Unexpected delta in diff application")
+				}
+				called = true
+				return true, nil
+			}
+
+			err = repo.ApplyDiff(diff, ApplyLocationBoth, opts)
+			checkFatal(t, err)
+
+			if called == false {
+				t.Error("apply hunk callback was not called")
+			}
+
+			checkSecondFileStaged(t, repo)
+		})
+
+		t.Run("Check delta callback returning false does not apply patch", func(t *testing.T) {
+			opts := resetAndGetOpts(t)
+
+			called := false
+			opts.ApplyDeltaCallback = func(hunk *DiffDelta) (apply bool, err error) {
+				if hunk.NewFile.Path != "file2" {
+					t.Error("Unexpected hunk in diff application")
+				}
+				called = true
+				return false, nil
+			}
+
+			err = repo.ApplyDiff(diff, ApplyLocationBoth, opts)
+			checkFatal(t, err)
+
+			if called == false {
+				t.Error("apply hunk callback was not called")
+			}
+
+			checkNoFilesStaged(t, repo)
+		})
+
+		t.Run("Check hunk callback returning causes application to fail", func(t *testing.T) {
+			opts := resetAndGetOpts(t)
+
+			called := false
+			opts.ApplyHunkCallback = func(hunk *DiffHunk) (apply bool, err error) {
+				called = true
+				return false, errors.New("something happened")
+			}
+
+			err = repo.ApplyDiff(diff, ApplyLocationBoth, opts)
+			if err == nil {
+				t.Error("expected an error after trying to apply")
+			}
+
+			if called == false {
+				t.Error("apply hunk callback was not called")
+			}
+
+			checkNoFilesStaged(t, repo)
+		})
+
+		t.Run("Check delta callback returning causes application to fail", func(t *testing.T) {
+			opts := resetAndGetOpts(t)
+
+			called := false
+			opts.ApplyDeltaCallback = func(hunk *DiffDelta) (apply bool, err error) {
+				if hunk.NewFile.Path != "file2" {
+					t.Error("Unexpected delta in diff application")
+				}
+				called = true
+				return false, errors.New("something happened")
+			}
+
+			err = repo.ApplyDiff(diff, ApplyLocationBoth, opts)
+			if err == nil {
+				t.Error("expected an error after trying to apply")
+			}
+
+			if called == false {
+				t.Error("apply hunk callback was not called")
+			}
+
+			checkNoFilesStaged(t, repo)
+		})
+	})
+}
+
+func TestApplyToTree(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	commitA, treeA := addAndGetTree(t, repo, "file", "a")
+	defer commitA.Free()
+	defer treeA.Free()
+	commitB, treeB := addAndGetTree(t, repo, "file", "b")
+	defer commitB.Free()
+	defer treeB.Free()
+	commitC, treeC := addAndGetTree(t, repo, "file", "c")
+	defer commitC.Free()
+	defer treeC.Free()
+
+	diffAB, err := repo.DiffTreeToTree(treeA, treeB, nil)
+	checkFatal(t, err)
+
+	diffAC, err := repo.DiffTreeToTree(treeA, treeC, nil)
+	checkFatal(t, err)
+
+	errMessageDropped := errors.New("message dropped")
+
+	for _, tc := range []struct {
+		name               string
+		tree               *Tree
+		diff               *Diff
+		applyHunkCallback  ApplyHunkCallback
+		applyDeltaCallback ApplyDeltaCallback
+		err                error
+		expectedDiff       *Diff
+	}{
+		{
+			name:         "applying patch produces the same diff",
+			tree:         treeA,
+			diff:         diffAB,
+			expectedDiff: diffAB,
+		},
+		{
+			name: "applying a conflicting patch errors",
+			tree: treeB,
+			diff: diffAC,
+			err: &GitError{
+				Message: "hunk at line 1 did not apply",
+				Code:    ErrorCodeApplyFail,
+				Class:   ErrorClassPatch,
+			},
+		},
+		{
+			name:               "callbacks succeeding apply the diff",
+			tree:               treeA,
+			diff:               diffAB,
+			applyHunkCallback:  func(*DiffHunk) (bool, error) { return true, nil },
+			applyDeltaCallback: func(*DiffDelta) (bool, error) { return true, nil },
+			expectedDiff:       diffAB,
+		},
+		{
+			name:              "hunk callback returning false does not apply",
+			tree:              treeA,
+			diff:              diffAB,
+			applyHunkCallback: func(*DiffHunk) (bool, error) { return false, nil },
+		},
+		{
+			name:              "hunk callback erroring fails the call",
+			tree:              treeA,
+			diff:              diffAB,
+			applyHunkCallback: func(*DiffHunk) (bool, error) { return true, errMessageDropped },
+			err:               errMessageDropped,
+		},
+		{
+			name:               "delta callback returning false does not apply",
+			tree:               treeA,
+			diff:               diffAB,
+			applyDeltaCallback: func(*DiffDelta) (bool, error) { return false, nil },
+		},
+		{
+			name:               "delta callback erroring fails the call",
+			tree:               treeA,
+			diff:               diffAB,
+			applyDeltaCallback: func(*DiffDelta) (bool, error) { return true, errMessageDropped },
+			err:                errMessageDropped,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			opts, err := DefaultApplyOptions()
+			checkFatal(t, err)
+
+			opts.ApplyHunkCallback = tc.applyHunkCallback
+			opts.ApplyDeltaCallback = tc.applyDeltaCallback
+
+			index, err := repo.ApplyToTree(tc.diff, tc.tree, opts)
+			if tc.err != nil {
+				if !reflect.DeepEqual(tc.err, err) {
+					t.Fatalf("expected error %q but got %q", tc.err, err)
+				}
+
+				return
+			}
+			checkFatal(t, err)
+
+			patchedTreeOID, err := index.WriteTreeTo(repo)
+			checkFatal(t, err)
+
+			patchedTree, err := repo.LookupTree(patchedTreeOID)
+			checkFatal(t, err)
+
+			patchedDiff, err := repo.DiffTreeToTree(tc.tree, patchedTree, nil)
+			checkFatal(t, err)
+
+			appliedRaw, err := patchedDiff.ToBuf(DiffFormatPatch)
+			checkFatal(t, err)
+
+			if tc.expectedDiff == nil {
+				if len(appliedRaw) > 0 {
+					t.Fatalf("expected no diff but got: %s", appliedRaw)
+				}
+
+				return
+			}
+
+			expectedDiff, err := tc.expectedDiff.ToBuf(DiffFormatPatch)
+			checkFatal(t, err)
+
+			if string(expectedDiff) != string(appliedRaw) {
+				t.Fatalf("diffs do not match:\nexpected: %s\n\nactual: %s", expectedDiff, appliedRaw)
+			}
+		})
+	}
+}
+
+// checkSecondFileStaged checks that there is a single file called "file2" uncommitted in the repo
+func checkSecondFileStaged(t *testing.T, repo *Repository) {
+	opts := StatusOptions{
+		Show:  StatusShowIndexAndWorkdir,
+		Flags: StatusOptIncludeUntracked,
+	}
+
+	statuses, err := repo.StatusList(&opts)
+	checkFatal(t, err)
+
+	count, err := statuses.EntryCount()
+	checkFatal(t, err)
+
+	if count != 1 {
+		t.Error("diff should affect exactly one file")
+	}
+	if count == 0 {
+		t.Fatal("no statuses, cannot continue test")
+	}
+
+	entry, err := statuses.ByIndex(0)
+	checkFatal(t, err)
+
+	if entry.Status != StatusIndexNew {
+		t.Error("status should be 'new' as file has been added between commits")
+	}
+
+	if entry.HeadToIndex.NewFile.Path != "file2" {
+		t.Error("new file should be 'file2")
+	}
+	return
+}
+
+// checkNoFilesStaged checks that there is a single file called "file2" uncommitted in the repo
+func checkNoFilesStaged(t *testing.T, repo *Repository) {
+	opts := StatusOptions{
+		Show:  StatusShowIndexAndWorkdir,
+		Flags: StatusOptIncludeUntracked,
+	}
+
+	statuses, err := repo.StatusList(&opts)
+	checkFatal(t, err)
+
+	count, err := statuses.EntryCount()
+	checkFatal(t, err)
+
+	if count != 0 {
+		t.Error("files changed unexpectedly")
+	}
+}
+
+// addAndGetTree creates a file and commits it, returning the commit and tree
+func addAndGetTree(t *testing.T, repo *Repository, filename string, content string) (*Commit, *Tree) {
+	headCommit, err := headCommit(repo)
+	checkFatal(t, err)
+	defer headCommit.Free()
+
+	p := repo.Path()
+	p = strings.TrimSuffix(p, ".git")
+	p = strings.TrimSuffix(p, ".git/")
+
+	err = ioutil.WriteFile(path.Join(p, filename), []byte((content)), 0777)
+	checkFatal(t, err)
+
+	index, err := repo.Index()
+	checkFatal(t, err)
+	defer index.Free()
+
+	err = index.AddByPath(filename)
+	checkFatal(t, err)
+
+	newTreeOID, err := index.WriteTreeTo(repo)
+	checkFatal(t, err)
+
+	newTree, err := repo.LookupTree(newTreeOID)
+	checkFatal(t, err)
+	defer newTree.Free()
+
+	commitId, err := repo.CreateCommit("HEAD", signature(), signature(), fmt.Sprintf("add %s", filename), newTree, headCommit)
+	checkFatal(t, err)
+
+	commit, err := repo.LookupCommit(commitId)
+	checkFatal(t, err)
+
+	tree, err := commit.Tree()
+	checkFatal(t, err)
+
+	return commit, tree
+}

difflinetype_string.go

@@ -0,0 +1,56 @@
+// Code generated by "stringer -type DiffLineType -trimprefix DiffLine -tags static"; DO NOT EDIT.
+
+package git
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[DiffLineContext-32]
+	_ = x[DiffLineAddition-43]
+	_ = x[DiffLineDeletion-45]
+	_ = x[DiffLineContextEOFNL-61]
+	_ = x[DiffLineAddEOFNL-62]
+	_ = x[DiffLineDelEOFNL-60]
+	_ = x[DiffLineFileHdr-70]
+	_ = x[DiffLineHunkHdr-72]
+	_ = x[DiffLineBinary-66]
+}
+
+const (
+	_DiffLineType_name_0 = "Context"
+	_DiffLineType_name_1 = "Addition"
+	_DiffLineType_name_2 = "Deletion"
+	_DiffLineType_name_3 = "DelEOFNLContextEOFNLAddEOFNL"
+	_DiffLineType_name_4 = "Binary"
+	_DiffLineType_name_5 = "FileHdr"
+	_DiffLineType_name_6 = "HunkHdr"
+)
+
+var (
+	_DiffLineType_index_3 = [...]uint8{0, 8, 20, 28}
+)
+
+func (i DiffLineType) String() string {
+	switch {
+	case i == 32:
+		return _DiffLineType_name_0
+	case i == 43:
+		return _DiffLineType_name_1
+	case i == 45:
+		return _DiffLineType_name_2
+	case 60 <= i && i <= 62:
+		i -= 60
+		return _DiffLineType_name_3[_DiffLineType_index_3[i]:_DiffLineType_index_3[i+1]]
+	case i == 66:
+		return _DiffLineType_name_4
+	case i == 70:
+		return _DiffLineType_name_5
+	case i == 72:
+		return _DiffLineType_name_6
+	default:
+		return "DiffLineType(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}

errorclass_string.go

@@ -0,0 +1,63 @@
+// Code generated by "stringer -type ErrorClass -trimprefix ErrorClass -tags static"; DO NOT EDIT.
+
+package git
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[ErrorClassNone-0]
+	_ = x[ErrorClassNoMemory-1]
+	_ = x[ErrorClassOS-2]
+	_ = x[ErrorClassInvalid-3]
+	_ = x[ErrorClassReference-4]
+	_ = x[ErrorClassZlib-5]
+	_ = x[ErrorClassRepository-6]
+	_ = x[ErrorClassConfig-7]
+	_ = x[ErrorClassRegex-8]
+	_ = x[ErrorClassOdb-9]
+	_ = x[ErrorClassIndex-10]
+	_ = x[ErrorClassObject-11]
+	_ = x[ErrorClassNet-12]
+	_ = x[ErrorClassTag-13]
+	_ = x[ErrorClassTree-14]
+	_ = x[ErrorClassIndexer-15]
+	_ = x[ErrorClassSSL-16]
+	_ = x[ErrorClassSubmodule-17]
+	_ = x[ErrorClassThread-18]
+	_ = x[ErrorClassStash-19]
+	_ = x[ErrorClassCheckout-20]
+	_ = x[ErrorClassFetchHead-21]
+	_ = x[ErrorClassMerge-22]
+	_ = x[ErrorClassSSH-23]
+	_ = x[ErrorClassFilter-24]
+	_ = x[ErrorClassRevert-25]
+	_ = x[ErrorClassCallback-26]
+	_ = x[ErrorClassRebase-29]
+	_ = x[ErrorClassPatch-31]
+}
+
+const (
+	_ErrorClass_name_0 = "NoneNoMemoryOSInvalidReferenceZlibRepositoryConfigRegexOdbIndexObjectNetTagTreeIndexerSSLSubmoduleThreadStashCheckoutFetchHeadMergeSSHFilterRevertCallback"
+	_ErrorClass_name_1 = "Rebase"
+	_ErrorClass_name_2 = "Patch"
+)
+
+var (
+	_ErrorClass_index_0 = [...]uint8{0, 4, 12, 14, 21, 30, 34, 44, 50, 55, 58, 63, 69, 72, 75, 79, 86, 89, 98, 104, 109, 117, 126, 131, 134, 140, 146, 154}
+)
+
+func (i ErrorClass) String() string {
+	switch {
+	case 0 <= i && i <= 26:
+		return _ErrorClass_name_0[_ErrorClass_index_0[i]:_ErrorClass_index_0[i+1]]
+	case i == 29:
+		return _ErrorClass_name_1
+	case i == 31:
+		return _ErrorClass_name_2
+	default:
+		return "ErrorClass(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}

errorcode_string.go

@@ -0,0 +1,69 @@
+// Code generated by "stringer -type ErrorCode -trimprefix ErrorCode -tags static"; DO NOT EDIT.
+
+package git
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[ErrorCodeOK-0]
+	_ = x[ErrorCodeGeneric - -1]
+	_ = x[ErrorCodeNotFound - -3]
+	_ = x[ErrorCodeExists - -4]
+	_ = x[ErrorCodeAmbiguous - -5]
+	_ = x[ErrorCodeBuffs - -6]
+	_ = x[ErrorCodeUser - -7]
+	_ = x[ErrorCodeBareRepo - -8]
+	_ = x[ErrorCodeUnbornBranch - -9]
+	_ = x[ErrorCodeUnmerged - -10]
+	_ = x[ErrorCodeNonFastForward - -11]
+	_ = x[ErrorCodeInvalidSpec - -12]
+	_ = x[ErrorCodeConflict - -13]
+	_ = x[ErrorCodeLocked - -14]
+	_ = x[ErrorCodeModified - -15]
+	_ = x[ErrorCodeAuth - -16]
+	_ = x[ErrorCodeCertificate - -17]
+	_ = x[ErrorCodeApplied - -18]
+	_ = x[ErrorCodePeel - -19]
+	_ = x[ErrorCodeEOF - -20]
+	_ = x[ErrorCodeInvalid - -21]
+	_ = x[ErrorCodeUncommitted - -22]
+	_ = x[ErrorCodeDirectory - -23]
+	_ = x[ErrorCodeMergeConflict - -24]
+	_ = x[ErrorCodePassthrough - -30]
+	_ = x[ErrorCodeIterOver - -31]
+	_ = x[ErrorCodeRetry - -32]
+	_ = x[ErrorCodeMismatch - -33]
+	_ = x[ErrorCodeIndexDirty - -34]
+	_ = x[ErrorCodeApplyFail - -35]
+}
+
+const (
+	_ErrorCode_name_0 = "ApplyFailIndexDirtyMismatchRetryIterOverPassthrough"
+	_ErrorCode_name_1 = "MergeConflictDirectoryUncommittedInvalidEOFPeelAppliedCertificateAuthModifiedLockedConflictInvalidSpecNonFastForwardUnmergedUnbornBranchBareRepoUserBuffsAmbiguousExistsNotFound"
+	_ErrorCode_name_2 = "GenericOK"
+)
+
+var (
+	_ErrorCode_index_0 = [...]uint8{0, 9, 19, 27, 32, 40, 51}
+	_ErrorCode_index_1 = [...]uint8{0, 13, 22, 33, 40, 43, 47, 54, 65, 69, 77, 83, 91, 102, 116, 124, 136, 144, 148, 153, 162, 168, 176}
+	_ErrorCode_index_2 = [...]uint8{0, 7, 9}
+)
+
+func (i ErrorCode) String() string {
+	switch {
+	case -35 <= i && i <= -30:
+		i -= -35
+		return _ErrorCode_name_0[_ErrorCode_index_0[i]:_ErrorCode_index_0[i+1]]
+	case -24 <= i && i <= -3:
+		i -= -24
+		return _ErrorCode_name_1[_ErrorCode_index_1[i]:_ErrorCode_index_1[i+1]]
+	case -1 <= i && i <= 0:
+		i -= -1
+		return _ErrorCode_name_2[_ErrorCode_index_2[i]:_ErrorCode_index_2[i+1]]
+	default:
+		return "ErrorCode(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}

features.go

@@ -0,0 +1,30 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+
+type Feature int
+
+const (
+	// libgit2 was built with threading support
+	FeatureThreads Feature = C.GIT_FEATURE_THREADS
+
+	// libgit2 was built with HTTPS support built-in
+	FeatureHTTPS Feature = C.GIT_FEATURE_HTTPS
+
+	// libgit2 was build with SSH support built-in
+	FeatureSSH Feature = C.GIT_FEATURE_SSH
+
+	// libgit2 was built with nanosecond support for files
+	FeatureNSec Feature = C.GIT_FEATURE_NSEC
+)
+
+// Features returns a bit-flag of Feature values indicating which features the
+// loaded libgit2 library has.
+func Features() Feature {
+	features := C.git_libgit2_features()
+
+	return Feature(features)
+}

git.go

@@ -1,104 +1,264 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
+#include <git2/sys/openssl.h>
 */
 import "C"
 import (
 	"bytes"
+	"encoding/hex"
 	"errors"
-	"unsafe"
+	"runtime"
 	"strings"
+	"unsafe"
 )
 
+//go:generate stringer -type ErrorClass -trimprefix ErrorClass -tags static
+type ErrorClass int
+
 const (
-	ITEROVER  = C.GIT_ITEROVER
-	EEXISTS   = C.GIT_EEXISTS
-	ENOTFOUND = C.GIT_ENOTFOUND
+	ErrorClassNone       ErrorClass = C.GIT_ERROR_NONE
+	ErrorClassNoMemory   ErrorClass = C.GIT_ERROR_NOMEMORY
+	ErrorClassOS         ErrorClass = C.GIT_ERROR_OS
+	ErrorClassInvalid    ErrorClass = C.GIT_ERROR_INVALID
+	ErrorClassReference  ErrorClass = C.GIT_ERROR_REFERENCE
+	ErrorClassZlib       ErrorClass = C.GIT_ERROR_ZLIB
+	ErrorClassRepository ErrorClass = C.GIT_ERROR_REPOSITORY
+	ErrorClassConfig     ErrorClass = C.GIT_ERROR_CONFIG
+	ErrorClassRegex      ErrorClass = C.GIT_ERROR_REGEX
+	ErrorClassOdb        ErrorClass = C.GIT_ERROR_ODB
+	ErrorClassIndex      ErrorClass = C.GIT_ERROR_INDEX
+	ErrorClassObject     ErrorClass = C.GIT_ERROR_OBJECT
+	ErrorClassNet        ErrorClass = C.GIT_ERROR_NET
+	ErrorClassTag        ErrorClass = C.GIT_ERROR_TAG
+	ErrorClassTree       ErrorClass = C.GIT_ERROR_TREE
+	ErrorClassIndexer    ErrorClass = C.GIT_ERROR_INDEXER
+	ErrorClassSSL        ErrorClass = C.GIT_ERROR_SSL
+	ErrorClassSubmodule  ErrorClass = C.GIT_ERROR_SUBMODULE
+	ErrorClassThread     ErrorClass = C.GIT_ERROR_THREAD
+	ErrorClassStash      ErrorClass = C.GIT_ERROR_STASH
+	ErrorClassCheckout   ErrorClass = C.GIT_ERROR_CHECKOUT
+	ErrorClassFetchHead  ErrorClass = C.GIT_ERROR_FETCHHEAD
+	ErrorClassMerge      ErrorClass = C.GIT_ERROR_MERGE
+	ErrorClassSSH        ErrorClass = C.GIT_ERROR_SSH
+	ErrorClassFilter     ErrorClass = C.GIT_ERROR_FILTER
+	ErrorClassRevert     ErrorClass = C.GIT_ERROR_REVERT
+	ErrorClassCallback   ErrorClass = C.GIT_ERROR_CALLBACK
+	ErrorClassRebase     ErrorClass = C.GIT_ERROR_REBASE
+	ErrorClassPatch      ErrorClass = C.GIT_ERROR_PATCH
+)
+
+//go:generate stringer -type ErrorCode -trimprefix ErrorCode -tags static
+type ErrorCode int
+
+const (
+	// ErrorCodeOK indicates that the operation completed successfully.
+	ErrorCodeOK ErrorCode = C.GIT_OK
+
+	// ErrorCodeGeneric represents a generic error.
+	ErrorCodeGeneric ErrorCode = C.GIT_ERROR
+	// ErrorCodeNotFound represents that the requested object could not be found
+	ErrorCodeNotFound ErrorCode = C.GIT_ENOTFOUND
+	// ErrorCodeExists represents that the object exists preventing operation.
+	ErrorCodeExists ErrorCode = C.GIT_EEXISTS
+	// ErrorCodeAmbiguous represents that more than one object matches.
+	ErrorCodeAmbiguous ErrorCode = C.GIT_EAMBIGUOUS
+	// ErrorCodeBuffs represents that the output buffer is too short to hold data.
+	ErrorCodeBuffs ErrorCode = C.GIT_EBUFS
+
+	// ErrorCodeUser is a special error that is never generated by libgit2
+	// code.  You can return it from a callback (e.g to stop an iteration)
+	// to know that it was generated by the callback and not by libgit2.
+	ErrorCodeUser ErrorCode = C.GIT_EUSER
+
+	// ErrorCodeBareRepo represents that the operation not allowed on bare repository
+	ErrorCodeBareRepo ErrorCode = C.GIT_EBAREREPO
+	// ErrorCodeUnbornBranch represents that HEAD refers to branch with no commits.
+	ErrorCodeUnbornBranch ErrorCode = C.GIT_EUNBORNBRANCH
+	// ErrorCodeUnmerged represents that a merge in progress prevented operation.
+	ErrorCodeUnmerged ErrorCode = C.GIT_EUNMERGED
+	// ErrorCodeNonFastForward represents that the reference was not fast-forwardable.
+	ErrorCodeNonFastForward ErrorCode = C.GIT_ENONFASTFORWARD
+	// ErrorCodeInvalidSpec represents that the name/ref spec was not in a valid format.
+	ErrorCodeInvalidSpec ErrorCode = C.GIT_EINVALIDSPEC
+	// ErrorCodeConflict represents that checkout conflicts prevented operation.
+	ErrorCodeConflict ErrorCode = C.GIT_ECONFLICT
+	// ErrorCodeLocked represents that lock file prevented operation.
+	ErrorCodeLocked ErrorCode = C.GIT_ELOCKED
+	// ErrorCodeModified represents that the reference value does not match expected.
+	ErrorCodeModified ErrorCode = C.GIT_EMODIFIED
+	// ErrorCodeAuth represents that the authentication failed.
+	ErrorCodeAuth ErrorCode = C.GIT_EAUTH
+	// ErrorCodeCertificate represents that the server certificate is invalid.
+	ErrorCodeCertificate ErrorCode = C.GIT_ECERTIFICATE
+	// ErrorCodeApplied represents that the patch/merge has already been applied.
+	ErrorCodeApplied ErrorCode = C.GIT_EAPPLIED
+	// ErrorCodePeel represents that the requested peel operation is not possible.
+	ErrorCodePeel ErrorCode = C.GIT_EPEEL
+	// ErrorCodeEOF represents an unexpected EOF.
+	ErrorCodeEOF ErrorCode = C.GIT_EEOF
+	// ErrorCodeInvalid represents an invalid operation or input.
+	ErrorCodeInvalid ErrorCode = C.GIT_EINVALID
+	// ErrorCodeUIncommitted represents that uncommitted changes in index prevented operation.
+	ErrorCodeUncommitted ErrorCode = C.GIT_EUNCOMMITTED
+	// ErrorCodeDirectory represents that the operation is not valid for a directory.
+	ErrorCodeDirectory ErrorCode = C.GIT_EDIRECTORY
+	// ErrorCodeMergeConflict represents that a merge conflict exists and cannot continue.
+	ErrorCodeMergeConflict ErrorCode = C.GIT_EMERGECONFLICT
+
+	// ErrorCodePassthrough represents that a user-configured callback refused to act.
+	ErrorCodePassthrough ErrorCode = C.GIT_PASSTHROUGH
+	// ErrorCodeIterOver signals end of iteration with iterator.
+	ErrorCodeIterOver ErrorCode = C.GIT_ITEROVER
+	// ErrorCodeRetry is an internal-only error code.
+	ErrorCodeRetry ErrorCode = C.GIT_RETRY
+	// ErrorCodeMismatch represents a hashsum mismatch in object.
+	ErrorCodeMismatch ErrorCode = C.GIT_EMISMATCH
+	// ErrorCodeIndexDirty represents that unsaved changes in the index would be overwritten.
+	ErrorCodeIndexDirty ErrorCode = C.GIT_EINDEXDIRTY
+	// ErrorCodeApplyFail represents that a patch application failed.
+	ErrorCodeApplyFail ErrorCode = C.GIT_EAPPLYFAIL
 )
 
 var (
-	ErrIterOver = errors.New("Iteration is over")
+	ErrInvalid = errors.New("Invalid state for operation")
 )
 
+// doNotCompare is an idiomatic way of making structs non-comparable to avoid
+// future field additions to make them non-comparable.
+type doNotCompare [0]func()
+
+var pointerHandles *HandleList
+var remotePointers *remotePointerList
+
 func init() {
-	C.git_threads_init()
+	initLibGit2()
 }
 
-// Oid
-type Oid struct {
-	bytes [20]byte
+func initLibGit2() {
+	pointerHandles = NewHandleList()
+	remotePointers = newRemotePointerList()
+
+	C.git_libgit2_init()
+	features := Features()
+
+	// Due to the multithreaded nature of Go and its interaction with
+	// calling C functions, we cannot work with a library that was not built
+	// with multi-threading support. The most likely outcome is a segfault
+	// or panic at an incomprehensible time, so let's make it easy by
+	// panicking right here.
+	if features&FeatureThreads == 0 {
+		panic("libgit2 was not built with threading support")
+	}
+
+	if features&FeatureHTTPS == 0 {
+		if err := registerManagedHTTP(); err != nil {
+			panic(err)
+		}
+	} else {
+		// This is not something we should be doing, as we may be stomping all over
+		// someone else's setup. The user should do this themselves or use some
+		// binding/wrapper which does it in such a way that they can be sure
+		// they're the only ones setting it up.
+		C.git_openssl_set_locking()
+	}
+	if features&FeatureSSH == 0 {
+		if err := registerManagedSSH(); err != nil {
+			panic(err)
+		}
+	}
 }
 
+// Shutdown frees all the resources acquired by libgit2. Make sure no
+// references to any libgit2 go objects are live before calling this.
+// After this is called, invoking any function from this library will result in
+// undefined behavior, so make sure this is called carefully.
+func Shutdown() {
+	if err := unregisterManagedTransports(); err != nil {
+		panic(err)
+	}
+	pointerHandles.Clear()
+	remotePointers.clear()
+
+	C.git_libgit2_shutdown()
+}
+
+// ReInit reinitializes the global state, this is useful if the effective user
+// id has changed and you want to update the stored search paths for gitconfig
+// files. This function frees any references to objects, so it should be called
+// before any other functions are called.
+func ReInit() {
+	Shutdown()
+	initLibGit2()
+}
+
+// Oid represents the id for a Git object.
+type Oid [20]byte
+
 func newOidFromC(coid *C.git_oid) *Oid {
 	if coid == nil {
 		return nil
 	}
 
 	oid := new(Oid)
-	copy(oid.bytes[0:20], C.GoBytes(unsafe.Pointer(coid), 20))
+	copy(oid[0:20], C.GoBytes(unsafe.Pointer(coid), 20))
 	return oid
 }
 
-func NewOid(b []byte) *Oid {
+func NewOidFromBytes(b []byte) *Oid {
 	oid := new(Oid)
-	copy(oid.bytes[0:20], b[0:20])
+	copy(oid[0:20], b[0:20])
 	return oid
 }
 
 func (oid *Oid) toC() *C.git_oid {
-	return (*C.git_oid)(unsafe.Pointer(&oid.bytes))
+	return (*C.git_oid)(unsafe.Pointer(oid))
 }
 
-func NewOidFromString(s string) (*Oid, error) {
-	o := new(Oid)
-	cs := C.CString(s)
-	defer C.free(unsafe.Pointer(cs))
-
-	if C.git_oid_fromstr(o.toC(), cs) < 0 {
-		return nil, LastError()
+func NewOid(s string) (*Oid, error) {
+	if len(s) > C.GIT_OID_HEXSZ {
+		return nil, errors.New("string is too long for oid")
 	}
 
+	o := new(Oid)
+
+	slice, err := hex.DecodeString(s)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(slice) != 20 {
+		return nil, &GitError{"invalid oid", ErrorClassNone, ErrorCodeGeneric}
+	}
+
+	copy(o[:], slice[:20])
 	return o, nil
 }
 
 func (oid *Oid) String() string {
-	buf := make([]byte, 40)
-	C.git_oid_fmt((*C.char)(unsafe.Pointer(&buf[0])), oid.toC())
-	return string(buf)
-}
-
-func (oid *Oid) Bytes() []byte {
-	return oid.bytes[0:]
+	return hex.EncodeToString(oid[:])
 }
 
 func (oid *Oid) Cmp(oid2 *Oid) int {
-	return bytes.Compare(oid.bytes[:], oid2.bytes[:])
+	return bytes.Compare(oid[:], oid2[:])
 }
 
 func (oid *Oid) Copy() *Oid {
-	ret := new(Oid)
-	copy(ret.bytes[:], oid.bytes[:])
-	return ret
+	ret := *oid
+	return &ret
 }
 
 func (oid *Oid) Equal(oid2 *Oid) bool {
-	return bytes.Equal(oid.bytes[:], oid2.bytes[:])
+	return *oid == *oid2
 }
 
 func (oid *Oid) IsZero() bool {
-	for _, a := range(oid.bytes) {
-		if a != '0' {
-			return false
-		}
-	}
-	return true
+	return *oid == Oid{}
 }
 
 func (oid *Oid) NCmp(oid2 *Oid, n uint) int {
-	return bytes.Compare(oid.bytes[:n], oid2.bytes[:n])
+	return bytes.Compare(oid[:n], oid2[:n])
 }
 
 func ShortenOids(ids []*Oid, minlen int) (int, error) {
@@ -109,49 +269,101 @@ func ShortenOids(ids []*Oid, minlen int) (int, error) {
 	defer C.git_oid_shorten_free(shorten)
 
 	var ret C.int
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	for _, id := range ids {
 		buf := make([]byte, 41)
 		C.git_oid_fmt((*C.char)(unsafe.Pointer(&buf[0])), id.toC())
 		buf[40] = 0
 		ret = C.git_oid_shorten_add(shorten, (*C.char)(unsafe.Pointer(&buf[0])))
 		if ret < 0 {
-			return int(ret), LastError()
+			return int(ret), MakeGitError(ret)
 		}
 	}
+	runtime.KeepAlive(ids)
 	return int(ret), nil
 }
 
 type GitError struct {
 	Message string
-	Code int
+	Class   ErrorClass
+	Code    ErrorCode
 }
 
-func (e GitError) Error() string{
+func (e GitError) Error() string {
 	return e.Message
 }
 
-func LastError() error {
-	err := C.giterr_last()
+func IsErrorClass(err error, c ErrorClass) bool {
 	if err == nil {
-		return &GitError{"No message", 0}
+		return false
 	}
-	return &GitError{C.GoString(err.message), int(err.klass)}
+	if gitError, ok := err.(*GitError); ok {
+		return gitError.Class == c
+	}
+	return false
+}
+
+func IsErrorCode(err error, c ErrorCode) bool {
+	if err == nil {
+		return false
+	}
+	if gitError, ok := err.(*GitError); ok {
+		return gitError.Code == c
+	}
+	return false
+}
+
+func MakeGitError(c C.int) error {
+	var errMessage string
+	var errClass ErrorClass
+	errorCode := ErrorCode(c)
+	if errorCode != ErrorCodeIterOver {
+		err := C.git_error_last()
+		if err != nil {
+			errMessage = C.GoString(err.message)
+			errClass = ErrorClass(err.klass)
+		} else {
+			errClass = ErrorClassInvalid
+		}
+	}
+	if errMessage == "" {
+		errMessage = errorCode.String()
+	}
+	return &GitError{errMessage, errClass, errorCode}
+}
+
+func MakeGitError2(err int) error {
+	return MakeGitError(C.int(err))
 }
 
 func cbool(b bool) C.int {
-	if (b) {
+	if b {
 		return C.int(1)
 	}
 	return C.int(0)
 }
 
 func ucbool(b bool) C.uint {
-	if (b) {
+	if b {
 		return C.uint(1)
 	}
 	return C.uint(0)
 }
 
+func setCallbackError(errorMessage **C.char, err error) C.int {
+	if err != nil {
+		*errorMessage = C.CString(err.Error())
+		if gitError, ok := err.(*GitError); ok {
+			return C.int(gitError.Code)
+		}
+		return C.int(ErrorCodeUser)
+	}
+	return C.int(ErrorCodeOK)
+}
+
 func Discover(start string, across_fs bool, ceiling_dirs []string) (string, error) {
 	ceildirs := C.CString(strings.Join(ceiling_dirs, string(C.GIT_PATH_LIST_SEPARATOR)))
 	defer C.free(unsafe.Pointer(ceildirs))
@@ -159,14 +371,16 @@ func Discover(start string, across_fs bool, ceiling_dirs []string) (string, erro
 	cstart := C.CString(start)
 	defer C.free(unsafe.Pointer(cstart))
 
-	retpath := (*C.char)(C.malloc(C.GIT_PATH_MAX))
-	defer C.free(unsafe.Pointer(retpath))
+	var buf C.git_buf
+	defer C.git_buf_dispose(&buf)
 
-	r := C.git_repository_discover(retpath, C.GIT_PATH_MAX, cstart, cbool(across_fs), ceildirs)
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
 
-	if r == 0 {
-		return C.GoString(retpath), nil
+	ret := C.git_repository_discover(&buf, cstart, cbool(across_fs), ceildirs)
+	if ret < 0 {
+		return "", MakeGitError(ret)
 	}
 
-	return "", LastError()
+	return C.GoString(buf.ptr), nil
 }

git_test.go

@@ -1,11 +1,63 @@
 package git
 
 import (
-	"testing"
+	"fmt"
 	"io/ioutil"
+	"os"
+	"path"
+	"reflect"
+	"testing"
 	"time"
 )
 
+func TestMain(m *testing.M) {
+	if err := registerManagedHTTP(); err != nil {
+		panic(err)
+	}
+
+	ret := m.Run()
+
+	if err := unregisterManagedTransports(); err != nil {
+		panic(err)
+	}
+
+	// Ensure that we are not leaking any pointer handles.
+	pointerHandles.Lock()
+	if len(pointerHandles.handles) > 0 {
+		for h, ptr := range pointerHandles.handles {
+			fmt.Printf("%016p: %v %+v\n", h, reflect.TypeOf(ptr), ptr)
+		}
+		panic("pointer handle list not empty")
+	}
+	pointerHandles.Unlock()
+
+	// Or remote pointers.
+	remotePointers.Lock()
+	if len(remotePointers.pointers) > 0 {
+		for ptr, remote := range remotePointers.pointers {
+			fmt.Printf("%016p: %+v\n", ptr, remote)
+		}
+		panic("remote pointer list not empty")
+	}
+	remotePointers.Unlock()
+
+	Shutdown()
+
+	os.Exit(ret)
+}
+
+func cleanupTestRepo(t *testing.T, r *Repository) {
+	var err error
+	if r.IsBare() {
+		err = os.RemoveAll(r.Path())
+	} else {
+		err = os.RemoveAll(r.Workdir())
+	}
+	checkFatal(t, err)
+
+	r.Free()
+}
+
 func createTestRepo(t *testing.T) *Repository {
 	// figure out where we can create the test repo
 	path, err := ioutil.TempDir("", "git2go")
@@ -14,13 +66,33 @@ func createTestRepo(t *testing.T) *Repository {
 	checkFatal(t, err)
 
 	tmpfile := "README"
-	err = ioutil.WriteFile(path + "/" + tmpfile, []byte("foo\n"), 0644)
+	err = ioutil.WriteFile(path+"/"+tmpfile, []byte("foo\n"), 0644)
+
 	checkFatal(t, err)
 
 	return repo
 }
 
+func createBareTestRepo(t *testing.T) *Repository {
+	// figure out where we can create the test repo
+	path, err := ioutil.TempDir("", "git2go")
+	checkFatal(t, err)
+	repo, err := InitRepository(path, true)
+	checkFatal(t, err)
+
+	return repo
+}
+
+// commitOptions contains any extra options for creating commits in the seed repo
+type commitOptions struct {
+	CommitSigningCallback
+}
+
 func seedTestRepo(t *testing.T, repo *Repository) (*Oid, *Oid) {
+	return seedTestRepoOpt(t, repo, commitOptions{})
+}
+
+func seedTestRepoOpt(t *testing.T, repo *Repository, opts commitOptions) (*Oid, *Oid) {
 	loc, err := time.LoadLocation("Europe/Berlin")
 	checkFatal(t, err)
 	sig := &Signature{
@@ -33,6 +105,8 @@ func seedTestRepo(t *testing.T, repo *Repository) (*Oid, *Oid) {
 	checkFatal(t, err)
 	err = idx.AddByPath("README")
 	checkFatal(t, err)
+	err = idx.Write()
+	checkFatal(t, err)
 	treeId, err := idx.WriteTree()
 	checkFatal(t, err)
 
@@ -42,6 +116,84 @@ func seedTestRepo(t *testing.T, repo *Repository) (*Oid, *Oid) {
 	commitId, err := repo.CreateCommit("HEAD", sig, sig, message, tree)
 	checkFatal(t, err)
 
+	if opts.CommitSigningCallback != nil {
+		commit, err := repo.LookupCommit(commitId)
+		checkFatal(t, err)
+
+		signature, signatureField, err := opts.CommitSigningCallback(commit.ContentToSign())
+		checkFatal(t, err)
+
+		oid, err := commit.WithSignature(signature, signatureField)
+		checkFatal(t, err)
+		newCommit, err := repo.LookupCommit(oid)
+		checkFatal(t, err)
+		head, err := repo.Head()
+		checkFatal(t, err)
+		_, err = repo.References.Create(
+			head.Name(),
+			newCommit.Id(),
+			true,
+			"repoint to signed commit",
+		)
+		checkFatal(t, err)
+	}
+
 	return commitId, treeId
 }
 
+func pathInRepo(repo *Repository, name string) string {
+	return path.Join(path.Dir(path.Dir(repo.Path())), name)
+}
+
+func updateReadme(t *testing.T, repo *Repository, content string) (*Oid, *Oid) {
+	loc, err := time.LoadLocation("Europe/Berlin")
+	checkFatal(t, err)
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Date(2013, 03, 06, 14, 30, 0, 0, loc),
+	}
+
+	tmpfile := "README"
+	err = ioutil.WriteFile(pathInRepo(repo, tmpfile), []byte(content), 0644)
+	checkFatal(t, err)
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+	err = idx.AddByPath("README")
+	checkFatal(t, err)
+	err = idx.Write()
+	checkFatal(t, err)
+	treeId, err := idx.WriteTree()
+	checkFatal(t, err)
+
+	currentBranch, err := repo.Head()
+	checkFatal(t, err)
+	currentTip, err := repo.LookupCommit(currentBranch.Target())
+	checkFatal(t, err)
+
+	message := "This is a commit\n"
+	tree, err := repo.LookupTree(treeId)
+	checkFatal(t, err)
+	commitId, err := repo.CreateCommit("HEAD", sig, sig, message, tree, currentTip)
+	checkFatal(t, err)
+
+	return commitId, treeId
+}
+
+func TestOidZero(t *testing.T) {
+	t.Parallel()
+	var zeroId Oid
+
+	if !zeroId.IsZero() {
+		t.Error("Zero Oid is not zero")
+	}
+}
+
+func TestEmptyOid(t *testing.T) {
+	t.Parallel()
+	_, err := NewOid("")
+	if err == nil || !IsErrorCode(err, ErrorCodeGeneric) {
+		t.Fatal("Should have returned invalid error")
+	}
+}

graph.go

@@ -0,0 +1,69 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+)
+
+func (repo *Repository) DescendantOf(commit, ancestor *Oid) (bool, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_graph_descendant_of(repo.ptr, commit.toC(), ancestor.toC())
+	runtime.KeepAlive(repo)
+	runtime.KeepAlive(commit)
+	runtime.KeepAlive(ancestor)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+
+	return (ret > 0), nil
+}
+
+func (repo *Repository) AheadBehind(local, upstream *Oid) (ahead, behind int, err error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var aheadT C.size_t
+	var behindT C.size_t
+
+	ret := C.git_graph_ahead_behind(&aheadT, &behindT, repo.ptr, local.toC(), upstream.toC())
+	runtime.KeepAlive(repo)
+	runtime.KeepAlive(local)
+	runtime.KeepAlive(upstream)
+	if ret < 0 {
+		return 0, 0, MakeGitError(ret)
+	}
+
+	return int(aheadT), int(behindT), nil
+}
+
+// ReachableFromAny returns whether a commit is reachable from any of a list of
+// commits by following parent edges.
+func (repo *Repository) ReachableFromAny(commit *Oid, descendants []*Oid) (bool, error) {
+	if len(descendants) == 0 {
+		return false, nil
+	}
+
+	coids := make([]C.git_oid, len(descendants))
+	for i := 0; i < len(descendants); i++ {
+		coids[i] = *descendants[i].toC()
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_graph_reachable_from_any(repo.ptr, commit.toC(), &coids[0], C.size_t(len(descendants)))
+	runtime.KeepAlive(repo)
+	runtime.KeepAlive(commit)
+	runtime.KeepAlive(coids)
+	runtime.KeepAlive(descendants)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+
+	return (ret > 0), nil
+}

graph_test.go

@@ -0,0 +1,75 @@
+package git
+
+import (
+	"testing"
+)
+
+func TestReachableFromAny(t *testing.T) {
+	repo, err := OpenRepository("testdata/TestGitRepository.git")
+	checkFatal(t, err)
+	defer repo.Free()
+
+	for name, tc := range map[string]struct {
+		reachable   bool
+		commit      string
+		descendants []string
+	}{
+		"empty": {
+			reachable: false,
+			commit:    "49322bb17d3acc9146f98c97d078513228bbf3c0",
+		},
+		"same": {
+			reachable:   true,
+			commit:      "49322bb17d3acc9146f98c97d078513228bbf3c0",
+			descendants: []string{"49322bb17d3acc9146f98c97d078513228bbf3c0"},
+		},
+		"unreachable": {
+			reachable:   false,
+			commit:      "ac7e7e44c1885efb472ad54a78327d66bfc4ecef",
+			descendants: []string{"58be4659bb571194ed4562d04b359d26216f526e"},
+		},
+		"unreachable-reverse": {
+			reachable:   false,
+			commit:      "58be4659bb571194ed4562d04b359d26216f526e",
+			descendants: []string{"ac7e7e44c1885efb472ad54a78327d66bfc4ecef"},
+		},
+		"root": {
+			reachable: false,
+			commit:    "42e4e7c5e507e113ebbb7801b16b52cf867b7ce1",
+			descendants: []string{
+				"ac7e7e44c1885efb472ad54a78327d66bfc4ecef",
+				"d86a2aada2f5e7ccf6f11880bfb9ab404e8a8864",
+				"f73b95671f326616d66b2afb3bdfcdbbce110b44",
+				"d0114ab8ac326bab30e3a657a0397578c5a1af88",
+			},
+		},
+		"head": {
+			reachable: false,
+			commit:    "49322bb17d3acc9146f98c97d078513228bbf3c0",
+			descendants: []string{
+				"ac7e7e44c1885efb472ad54a78327d66bfc4ecef",
+				"d86a2aada2f5e7ccf6f11880bfb9ab404e8a8864",
+				"f73b95671f326616d66b2afb3bdfcdbbce110b44",
+				"d0114ab8ac326bab30e3a657a0397578c5a1af88",
+			},
+		},
+	} {
+		tc := tc
+		t.Run(name, func(t *testing.T) {
+			commit, err := NewOid(tc.commit)
+			checkFatal(t, err)
+
+			descendants := make([]*Oid, len(tc.descendants))
+			for i, o := range tc.descendants {
+				descendants[i], err = NewOid(o)
+				checkFatal(t, err)
+			}
+			reachable, err := repo.ReachableFromAny(commit, descendants)
+			checkFatal(t, err)
+
+			if reachable != tc.reachable {
+				t.Errorf("ReachableFromAny(%s, %v) = %v, wanted %v", tc.commit, tc.descendants, reachable, tc.reachable)
+			}
+		})
+	}
+}

handles.go

@@ -0,0 +1,68 @@
+package git
+
+/*
+#include <stdlib.h>
+*/
+import "C"
+import (
+	"fmt"
+	"sync"
+	"unsafe"
+)
+
+type HandleList struct {
+	doNotCompare
+	sync.RWMutex
+	// stores the Go pointers
+	handles map[unsafe.Pointer]interface{}
+}
+
+func NewHandleList() *HandleList {
+	return &HandleList{
+		handles: make(map[unsafe.Pointer]interface{}),
+	}
+}
+
+// Track adds the given pointer to the list of pointers to track and
+// returns a pointer value which can be passed to C as an opaque
+// pointer.
+func (v *HandleList) Track(pointer interface{}) unsafe.Pointer {
+	handle := C.malloc(1)
+
+	v.Lock()
+	v.handles[handle] = pointer
+	v.Unlock()
+
+	return handle
+}
+
+// Untrack stops tracking the pointer given by the handle
+func (v *HandleList) Untrack(handle unsafe.Pointer) {
+	v.Lock()
+	delete(v.handles, handle)
+	C.free(handle)
+	v.Unlock()
+}
+
+// Clear stops tracking all the managed pointers.
+func (v *HandleList) Clear() {
+	v.Lock()
+	for handle := range v.handles {
+		delete(v.handles, handle)
+		C.free(handle)
+	}
+	v.Unlock()
+}
+
+// Get retrieves the pointer from the given handle
+func (v *HandleList) Get(handle unsafe.Pointer) interface{} {
+	v.RLock()
+	defer v.RUnlock()
+
+	ptr, ok := v.handles[handle]
+	if !ok {
+		panic(fmt.Sprintf("invalid pointer handle: %p", handle))
+	}
+
+	return ptr
+}

http.go

@@ -0,0 +1,243 @@
+package git
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"sync"
+)
+
+// RegisterManagedHTTPTransport registers a Go-native implementation of an
+// HTTP/S transport that doesn't rely on any system libraries (e.g.
+// libopenssl/libmbedtls).
+//
+// If Shutdown or ReInit are called, make sure that the smart transports are
+// freed before it.
+func RegisterManagedHTTPTransport(protocol string) (*RegisteredSmartTransport, error) {
+	return NewRegisteredSmartTransport(protocol, true, httpSmartSubtransportFactory)
+}
+
+func registerManagedHTTP() error {
+	globalRegisteredSmartTransports.Lock()
+	defer globalRegisteredSmartTransports.Unlock()
+
+	for _, protocol := range []string{"http", "https"} {
+		if _, ok := globalRegisteredSmartTransports.transports[protocol]; ok {
+			continue
+		}
+		managed, err := newRegisteredSmartTransport(protocol, true, httpSmartSubtransportFactory, true)
+		if err != nil {
+			return fmt.Errorf("failed to register transport for %q: %v", protocol, err)
+		}
+		globalRegisteredSmartTransports.transports[protocol] = managed
+	}
+	return nil
+}
+
+func httpSmartSubtransportFactory(remote *Remote, transport *Transport) (SmartSubtransport, error) {
+	var proxyFn func(*http.Request) (*url.URL, error)
+	remoteConnectOpts, err := transport.SmartRemoteConnectOptions()
+	if err != nil {
+		return nil, err
+	}
+	switch remoteConnectOpts.ProxyOptions.Type {
+	case ProxyTypeNone:
+		proxyFn = nil
+	case ProxyTypeAuto:
+		proxyFn = http.ProxyFromEnvironment
+	case ProxyTypeSpecified:
+		parsedUrl, err := url.Parse(remoteConnectOpts.ProxyOptions.Url)
+		if err != nil {
+			return nil, err
+		}
+
+		proxyFn = http.ProxyURL(parsedUrl)
+	}
+
+	return &httpSmartSubtransport{
+		transport: transport,
+		client: &http.Client{
+			Transport: &http.Transport{
+				Proxy: proxyFn,
+			},
+		},
+	}, nil
+}
+
+type httpSmartSubtransport struct {
+	transport *Transport
+	client    *http.Client
+}
+
+func (t *httpSmartSubtransport) Action(url string, action SmartServiceAction) (SmartSubtransportStream, error) {
+	var req *http.Request
+	var err error
+	switch action {
+	case SmartServiceActionUploadpackLs:
+		req, err = http.NewRequest("GET", url+"/info/refs?service=git-upload-pack", nil)
+
+	case SmartServiceActionUploadpack:
+		req, err = http.NewRequest("POST", url+"/git-upload-pack", nil)
+		if err != nil {
+			break
+		}
+		req.Header.Set("Content-Type", "application/x-git-upload-pack-request")
+
+	case SmartServiceActionReceivepackLs:
+		req, err = http.NewRequest("GET", url+"/info/refs?service=git-receive-pack", nil)
+
+	case SmartServiceActionReceivepack:
+		req, err = http.NewRequest("POST", url+"/info/refs?service=git-upload-pack", nil)
+		if err != nil {
+			break
+		}
+		req.Header.Set("Content-Type", "application/x-git-receive-pack-request")
+
+	default:
+		err = errors.New("unknown action")
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("User-Agent", "git/2.0 (libgit2)")
+
+	stream := newManagedHttpStream(t, req)
+	if req.Method == "POST" {
+		stream.recvReply.Add(1)
+		stream.sendRequestBackground()
+	}
+
+	return stream, nil
+}
+
+func (t *httpSmartSubtransport) Close() error {
+	return nil
+}
+
+func (t *httpSmartSubtransport) Free() {
+	t.client = nil
+}
+
+type httpSmartSubtransportStream struct {
+	owner       *httpSmartSubtransport
+	req         *http.Request
+	resp        *http.Response
+	reader      *io.PipeReader
+	writer      *io.PipeWriter
+	sentRequest bool
+	recvReply   sync.WaitGroup
+	httpError   error
+}
+
+func newManagedHttpStream(owner *httpSmartSubtransport, req *http.Request) *httpSmartSubtransportStream {
+	r, w := io.Pipe()
+	return &httpSmartSubtransportStream{
+		owner:  owner,
+		req:    req,
+		reader: r,
+		writer: w,
+	}
+}
+
+func (self *httpSmartSubtransportStream) Read(buf []byte) (int, error) {
+	if !self.sentRequest {
+		self.recvReply.Add(1)
+		if err := self.sendRequest(); err != nil {
+			return 0, err
+		}
+	}
+
+	if err := self.writer.Close(); err != nil {
+		return 0, err
+	}
+
+	self.recvReply.Wait()
+
+	if self.httpError != nil {
+		return 0, self.httpError
+	}
+
+	return self.resp.Body.Read(buf)
+}
+
+func (self *httpSmartSubtransportStream) Write(buf []byte) (int, error) {
+	if self.httpError != nil {
+		return 0, self.httpError
+	}
+	return self.writer.Write(buf)
+}
+
+func (self *httpSmartSubtransportStream) Free() {
+	if self.resp != nil {
+		self.resp.Body.Close()
+	}
+}
+
+func (self *httpSmartSubtransportStream) sendRequestBackground() {
+	go func() {
+		self.httpError = self.sendRequest()
+	}()
+	self.sentRequest = true
+}
+
+func (self *httpSmartSubtransportStream) sendRequest() error {
+	defer self.recvReply.Done()
+	self.resp = nil
+
+	var resp *http.Response
+	var err error
+	var userName string
+	var password string
+	for {
+		req := &http.Request{
+			Method: self.req.Method,
+			URL:    self.req.URL,
+			Header: self.req.Header,
+		}
+		if req.Method == "POST" {
+			req.Body = self.reader
+			req.ContentLength = -1
+		}
+
+		if userName != "" && password != "" {
+			req.SetBasicAuth(userName, password)
+		}
+		resp, err = http.DefaultClient.Do(req)
+		if err != nil {
+			return err
+		}
+
+		if resp.StatusCode == http.StatusOK {
+			break
+		}
+
+		if resp.StatusCode == http.StatusUnauthorized {
+			resp.Body.Close()
+
+			cred, err := self.owner.transport.SmartCredentials("", CredentialTypeUserpassPlaintext)
+			if err != nil {
+				return err
+			}
+			defer cred.Free()
+
+			userName, password, err = cred.GetUserpassPlaintext()
+			if err != nil {
+				return err
+			}
+
+			continue
+		}
+
+		// Any other error we treat as a hard error and punt back to the caller
+		resp.Body.Close()
+		return fmt.Errorf("Unhandled HTTP error %s", resp.Status)
+	}
+
+	self.sentRequest = true
+	self.resp = resp
+	return nil
+}

ignore.go

@@ -0,0 +1,54 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+func (v *Repository) AddIgnoreRule(rules string) error {
+	crules := C.CString(rules)
+	defer C.free(unsafe.Pointer(crules))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_ignore_add_rule(v.ptr, crules)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (v *Repository) ClearInternalIgnoreRules() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_ignore_clear_internal_rules(v.ptr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (v *Repository) IsPathIgnored(path string) (bool, error) {
+	var ignored C.int
+
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_ignore_path_is_ignored(&ignored, v.ptr, cpath)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+	return ignored == 1, nil
+}

index.go

@@ -1,33 +1,416 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
+
+extern int _go_git_index_add_all(git_index*, const git_strarray*, unsigned int, void*);
+extern int _go_git_index_update_all(git_index*, const git_strarray*, void*);
+extern int _go_git_index_remove_all(git_index*, const git_strarray*, void*);
+
 */
 import "C"
 import (
+	"fmt"
 	"runtime"
 	"unsafe"
 )
 
-type Index struct {
-	ptr *C.git_index
+type IndexMatchedPathCallback func(string, string) error
+type indexMatchedPathCallbackData struct {
+	callback    IndexMatchedPathCallback
+	errorTarget *error
 }
 
-func newIndexFromC(ptr *C.git_index) *Index {
-	idx := &Index{ptr}
+// IndexAddOption is a set of flags for APIs that add files matching pathspec.
+type IndexAddOption uint
+
+const (
+	IndexAddDefault              IndexAddOption = C.GIT_INDEX_ADD_DEFAULT
+	IndexAddForce                IndexAddOption = C.GIT_INDEX_ADD_FORCE
+	IndexAddDisablePathspecMatch IndexAddOption = C.GIT_INDEX_ADD_DISABLE_PATHSPEC_MATCH
+	IndexAddCheckPathspec        IndexAddOption = C.GIT_INDEX_ADD_CHECK_PATHSPEC
+)
+
+// IndexStageState indicates the state of the git index.
+type IndexStageState int
+
+const (
+	// IndexStageAny matches any index stage.
+	//
+	// Some index APIs take a stage to match; pass this value to match
+	// any entry matching the path regardless of stage.
+	IndexStageAny IndexStageState = C.GIT_INDEX_STAGE_ANY
+	// IndexStageNormal is a normal staged file in the index.
+	IndexStageNormal IndexStageState = C.GIT_INDEX_STAGE_NORMAL
+	// IndexStageAncestor is the ancestor side of a conflict.
+	IndexStageAncestor IndexStageState = C.GIT_INDEX_STAGE_ANCESTOR
+	// IndexStageOurs is the "ours" side of a conflict.
+	IndexStageOurs IndexStageState = C.GIT_INDEX_STAGE_OURS
+	// IndexStageTheirs is the "theirs" side of a conflict.
+	IndexStageTheirs IndexStageState = C.GIT_INDEX_STAGE_THEIRS
+)
+
+type Index struct {
+	doNotCompare
+	ptr  *C.git_index
+	repo *Repository
+}
+
+type IndexTime struct {
+	Seconds     int32
+	Nanoseconds uint32
+}
+
+type IndexEntry struct {
+	Ctime IndexTime
+	Mtime IndexTime
+	Mode  Filemode
+	Uid   uint32
+	Gid   uint32
+	Size  uint32
+	Id    *Oid
+	Path  string
+}
+
+func newIndexEntryFromC(entry *C.git_index_entry) *IndexEntry {
+	if entry == nil {
+		return nil
+	}
+	return &IndexEntry{
+		IndexTime{int32(entry.ctime.seconds), uint32(entry.ctime.nanoseconds)},
+		IndexTime{int32(entry.mtime.seconds), uint32(entry.mtime.nanoseconds)},
+		Filemode(entry.mode),
+		uint32(entry.uid),
+		uint32(entry.gid),
+		uint32(entry.file_size),
+		newOidFromC(&entry.id),
+		C.GoString(entry.path),
+	}
+}
+
+func populateCIndexEntry(source *IndexEntry, dest *C.git_index_entry) {
+	dest.ctime.seconds = C.int32_t(source.Ctime.Seconds)
+	dest.ctime.nanoseconds = C.uint32_t(source.Ctime.Nanoseconds)
+	dest.mtime.seconds = C.int32_t(source.Mtime.Seconds)
+	dest.mtime.nanoseconds = C.uint32_t(source.Mtime.Nanoseconds)
+	dest.mode = C.uint32_t(source.Mode)
+	dest.uid = C.uint32_t(source.Uid)
+	dest.gid = C.uint32_t(source.Gid)
+	dest.file_size = C.uint32_t(source.Size)
+	if source.Id != nil {
+		dest.id = *source.Id.toC()
+	}
+	dest.path = C.CString(source.Path)
+}
+
+func freeCIndexEntry(entry *C.git_index_entry) {
+	C.free(unsafe.Pointer(entry.path))
+}
+
+func newIndexFromC(ptr *C.git_index, repo *Repository) *Index {
+	idx := &Index{ptr: ptr, repo: repo}
 	runtime.SetFinalizer(idx, (*Index).Free)
 	return idx
 }
 
+// NewIndex allocates a new index. It won't be associated with any
+// file on the filesystem or repository
+func NewIndex() (*Index, error) {
+	var ptr *C.git_index
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if err := C.git_index_new(&ptr); err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return newIndexFromC(ptr, nil), nil
+}
+
+// OpenIndex creates a new index at the given path. If the file does
+// not exist it will be created when Write() is called.
+func OpenIndex(path string) (*Index, error) {
+	var ptr *C.git_index
+
+	var cpath = C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if err := C.git_index_open(&ptr, cpath); err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return newIndexFromC(ptr, nil), nil
+}
+
+// Path returns the index' path on disk or an empty string if it
+// exists only in memory.
+func (v *Index) Path() string {
+	ret := C.GoString(C.git_index_path(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
+}
+
+// Clear clears the index object in memory; changes must be explicitly
+// written to disk for them to take effect persistently
+func (v *Index) Clear() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C.git_index_clear(v.ptr)
+	runtime.KeepAlive(v)
+	if err < 0 {
+		return MakeGitError(err)
+	}
+	return nil
+}
+
+// Add adds or replaces the given entry to the index, making a copy of
+// the data
+func (v *Index) Add(entry *IndexEntry) error {
+	var centry C.git_index_entry
+
+	populateCIndexEntry(entry, &centry)
+	defer freeCIndexEntry(&centry)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C.git_index_add(v.ptr, &centry)
+	runtime.KeepAlive(v)
+	if err < 0 {
+		return MakeGitError(err)
+	}
+
+	return nil
+}
+
 func (v *Index) AddByPath(path string) error {
 	cstr := C.CString(path)
 	defer C.free(unsafe.Pointer(cstr))
 
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_index_add_bypath(v.ptr, cstr)
+	runtime.KeepAlive(v)
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+// AddFromBuffer adds or replaces an index entry from a buffer in memory
+func (v *Index) AddFromBuffer(entry *IndexEntry, buffer []byte) error {
+	var centry C.git_index_entry
+
+	populateCIndexEntry(entry, &centry)
+	defer freeCIndexEntry(&centry)
+
+	var cbuffer unsafe.Pointer
+	if len(buffer) > 0 {
+		cbuffer = unsafe.Pointer(&buffer[0])
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if err := C.git_index_add_from_buffer(v.ptr, &centry, cbuffer, C.size_t(len(buffer))); err < 0 {
+		return MakeGitError(err)
+	}
+
+	return nil
+}
+
+func (v *Index) AddAll(pathspecs []string, flags IndexAddOption, callback IndexMatchedPathCallback) error {
+	cpathspecs := C.git_strarray{}
+	cpathspecs.count = C.size_t(len(pathspecs))
+	cpathspecs.strings = makeCStringsFromStrings(pathspecs)
+	defer freeStrarray(&cpathspecs)
+
+	var err error
+	data := indexMatchedPathCallbackData{
+		callback:    callback,
+		errorTarget: &err,
+	}
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var handle unsafe.Pointer
+	if callback != nil {
+		handle = pointerHandles.Track(&data)
+		defer pointerHandles.Untrack(handle)
+	}
+
+	ret := C._go_git_index_add_all(
+		v.ptr,
+		&cpathspecs,
+		C.uint(flags),
+		handle,
+	)
+	runtime.KeepAlive(v)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (v *Index) UpdateAll(pathspecs []string, callback IndexMatchedPathCallback) error {
+	cpathspecs := C.git_strarray{}
+	cpathspecs.count = C.size_t(len(pathspecs))
+	cpathspecs.strings = makeCStringsFromStrings(pathspecs)
+	defer freeStrarray(&cpathspecs)
+
+	var err error
+	data := indexMatchedPathCallbackData{
+		callback:    callback,
+		errorTarget: &err,
+	}
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var handle unsafe.Pointer
+	if callback != nil {
+		handle = pointerHandles.Track(&data)
+		defer pointerHandles.Untrack(handle)
+	}
+
+	ret := C._go_git_index_update_all(
+		v.ptr,
+		&cpathspecs,
+		handle,
+	)
+	runtime.KeepAlive(v)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (v *Index) RemoveAll(pathspecs []string, callback IndexMatchedPathCallback) error {
+	cpathspecs := C.git_strarray{}
+	cpathspecs.count = C.size_t(len(pathspecs))
+	cpathspecs.strings = makeCStringsFromStrings(pathspecs)
+	defer freeStrarray(&cpathspecs)
+
+	var err error
+	data := indexMatchedPathCallbackData{
+		callback:    callback,
+		errorTarget: &err,
+	}
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var handle unsafe.Pointer
+	if callback != nil {
+		handle = pointerHandles.Track(&data)
+		defer pointerHandles.Untrack(handle)
+	}
+
+	ret := C._go_git_index_remove_all(
+		v.ptr,
+		&cpathspecs,
+		handle,
+	)
+	runtime.KeepAlive(v)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+//export indexMatchedPathCallback
+func indexMatchedPathCallback(cPath, cMatchedPathspec *C.char, payload unsafe.Pointer) C.int {
+	data, ok := pointerHandles.Get(payload).(*indexMatchedPathCallbackData)
+	if !ok {
+		panic("invalid matched path callback")
+	}
+
+	err := data.callback(C.GoString(cPath), C.GoString(cMatchedPathspec))
+	if err != nil {
+		*data.errorTarget = err
+		return C.int(ErrorCodeUser)
+	}
+
+	return C.int(ErrorCodeOK)
+}
+
+func (v *Index) RemoveByPath(path string) error {
+	cstr := C.CString(path)
+	defer C.free(unsafe.Pointer(cstr))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_index_remove_bypath(v.ptr, cstr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+// RemoveDirectory removes all entries from the index under a given directory.
+func (v *Index) RemoveDirectory(dir string, stage int) error {
+	cstr := C.CString(dir)
+	defer C.free(unsafe.Pointer(cstr))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_index_remove_directory(v.ptr, cstr, C.int(stage))
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (v *Index) WriteTreeTo(repo *Repository) (*Oid, error) {
+	oid := new(Oid)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_index_write_tree_to(oid.toC(), v.ptr, repo.ptr)
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(repo)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return oid, nil
+}
+
+// ReadTree replaces the contents of the index with those of the given
+// tree
+func (v *Index) ReadTree(tree *Tree) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_index_read_tree(v.ptr, tree.cast_ptr)
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(tree)
+	if ret < 0 {
+		return MakeGitError(ret)
 	}
 
 	return nil
@@ -35,15 +418,254 @@ func (v *Index) AddByPath(path string) error {
 
 func (v *Index) WriteTree() (*Oid, error) {
 	oid := new(Oid)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_index_write_tree(oid.toC(), v.ptr)
+	runtime.KeepAlive(v)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
 	return oid, nil
 }
 
+func (v *Index) Write() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_index_write(v.ptr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
 func (v *Index) Free() {
 	runtime.SetFinalizer(v, nil)
 	C.git_index_free(v.ptr)
 }
+
+func (v *Index) EntryCount() uint {
+	ret := uint(C.git_index_entrycount(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
+}
+
+func (v *Index) EntryByIndex(index uint) (*IndexEntry, error) {
+	centry := C.git_index_get_byindex(v.ptr, C.size_t(index))
+	if centry == nil {
+		return nil, fmt.Errorf("Index out of Bounds")
+	}
+	ret := newIndexEntryFromC(centry)
+	runtime.KeepAlive(v)
+	return ret, nil
+}
+
+func (v *Index) EntryByPath(path string, stage int) (*IndexEntry, error) {
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	centry := C.git_index_get_bypath(v.ptr, cpath, C.int(stage))
+	if centry == nil {
+		return nil, MakeGitError(C.int(ErrorCodeNotFound))
+	}
+	ret := newIndexEntryFromC(centry)
+	runtime.KeepAlive(v)
+	return ret, nil
+}
+
+func (v *Index) Find(path string) (uint, error) {
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var pos C.size_t
+	ret := C.git_index_find(&pos, v.ptr, cpath)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return uint(0), MakeGitError(ret)
+	}
+	return uint(pos), nil
+}
+
+func (v *Index) FindPrefix(prefix string) (uint, error) {
+	cprefix := C.CString(prefix)
+	defer C.free(unsafe.Pointer(cprefix))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var pos C.size_t
+	ret := C.git_index_find_prefix(&pos, v.ptr, cprefix)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return uint(0), MakeGitError(ret)
+	}
+	return uint(pos), nil
+}
+
+func (v *Index) HasConflicts() bool {
+	ret := C.git_index_has_conflicts(v.ptr) != 0
+	runtime.KeepAlive(v)
+	return ret
+}
+
+// FIXME: this might return an error
+func (v *Index) CleanupConflicts() {
+	C.git_index_conflict_cleanup(v.ptr)
+	runtime.KeepAlive(v)
+}
+
+func (v *Index) AddConflict(ancestor *IndexEntry, our *IndexEntry, their *IndexEntry) error {
+
+	var cancestor *C.git_index_entry
+	var cour *C.git_index_entry
+	var ctheir *C.git_index_entry
+
+	if ancestor != nil {
+		cancestor = &C.git_index_entry{}
+		populateCIndexEntry(ancestor, cancestor)
+		defer freeCIndexEntry(cancestor)
+	}
+
+	if our != nil {
+		cour = &C.git_index_entry{}
+		populateCIndexEntry(our, cour)
+		defer freeCIndexEntry(cour)
+	}
+
+	if their != nil {
+		ctheir = &C.git_index_entry{}
+		populateCIndexEntry(their, ctheir)
+		defer freeCIndexEntry(ctheir)
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_index_conflict_add(v.ptr, cancestor, cour, ctheir)
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(ancestor)
+	runtime.KeepAlive(our)
+	runtime.KeepAlive(their)
+	if ecode < 0 {
+		return MakeGitError(ecode)
+	}
+	return nil
+}
+
+type IndexConflict struct {
+	Ancestor *IndexEntry
+	Our      *IndexEntry
+	Their    *IndexEntry
+}
+
+func (v *Index) Conflict(path string) (IndexConflict, error) {
+
+	var cancestor *C.git_index_entry
+	var cour *C.git_index_entry
+	var ctheir *C.git_index_entry
+
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_index_conflict_get(&cancestor, &cour, &ctheir, v.ptr, cpath)
+	if ecode < 0 {
+		return IndexConflict{}, MakeGitError(ecode)
+	}
+	ret := IndexConflict{
+		Ancestor: newIndexEntryFromC(cancestor),
+		Our:      newIndexEntryFromC(cour),
+		Their:    newIndexEntryFromC(ctheir),
+	}
+	runtime.KeepAlive(v)
+	return ret, nil
+}
+
+// deprecated: You should use `Index.Conflict()` instead.
+func (v *Index) GetConflict(path string) (IndexConflict, error) {
+	return v.Conflict(path)
+}
+
+func (v *Index) RemoveConflict(path string) error {
+
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_index_conflict_remove(v.ptr, cpath)
+	runtime.KeepAlive(v)
+	if ecode < 0 {
+		return MakeGitError(ecode)
+	}
+	return nil
+}
+
+type IndexConflictIterator struct {
+	doNotCompare
+	ptr   *C.git_index_conflict_iterator
+	index *Index
+}
+
+func newIndexConflictIteratorFromC(index *Index, ptr *C.git_index_conflict_iterator) *IndexConflictIterator {
+	i := &IndexConflictIterator{ptr: ptr, index: index}
+	runtime.SetFinalizer(i, (*IndexConflictIterator).Free)
+	return i
+}
+
+func (v *IndexConflictIterator) Index() *Index {
+	return v.index
+}
+
+func (v *IndexConflictIterator) Free() {
+	runtime.SetFinalizer(v, nil)
+	C.git_index_conflict_iterator_free(v.ptr)
+}
+
+func (v *Index) ConflictIterator() (*IndexConflictIterator, error) {
+	var i *C.git_index_conflict_iterator
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_index_conflict_iterator_new(&i, v.ptr)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+	return newIndexConflictIteratorFromC(v, i), nil
+}
+
+func (v *IndexConflictIterator) Next() (IndexConflict, error) {
+	var cancestor *C.git_index_entry
+	var cour *C.git_index_entry
+	var ctheir *C.git_index_entry
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_index_conflict_next(&cancestor, &cour, &ctheir, v.ptr)
+	if ecode < 0 {
+		return IndexConflict{}, MakeGitError(ecode)
+	}
+	ret := IndexConflict{
+		Ancestor: newIndexEntryFromC(cancestor),
+		Our:      newIndexEntryFromC(cour),
+		Their:    newIndexEntryFromC(ctheir),
+	}
+	runtime.KeepAlive(v)
+	return ret, nil
+}

index_test.go

@@ -1,14 +1,17 @@
 package git
 
 import (
+	"io/ioutil"
 	"os"
+	"path"
 	"runtime"
 	"testing"
 )
 
 func TestCreateRepoAndStage(t *testing.T) {
+	t.Parallel()
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	idx, err := repo.Index()
 	checkFatal(t, err)
@@ -22,6 +25,249 @@ func TestCreateRepoAndStage(t *testing.T) {
 	}
 }
 
+func TestIndexReadTree(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, _ = seedTestRepo(t, repo)
+
+	ref, err := repo.Head()
+	checkFatal(t, err)
+
+	obj, err := ref.Peel(ObjectTree)
+	checkFatal(t, err)
+
+	tree, err := obj.AsTree()
+	checkFatal(t, err)
+
+	idx, err := NewIndex()
+	checkFatal(t, err)
+
+	err = idx.ReadTree(tree)
+	checkFatal(t, err)
+
+	id, err := idx.WriteTreeTo(repo)
+	checkFatal(t, err)
+
+	if tree.Id().Cmp(id) != 0 {
+		t.Fatalf("Read and written trees are not the same")
+	}
+}
+
+func TestIndexWriteTreeTo(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	idx, err := NewIndex()
+	checkFatal(t, err)
+
+	odb, err := repo.Odb()
+	checkFatal(t, err)
+
+	content, err := ioutil.ReadFile(path.Join(repo.Workdir(), "README"))
+	checkFatal(t, err)
+
+	id, err := odb.Write(content, ObjectBlob)
+	checkFatal(t, err)
+
+	err = idx.Add(&IndexEntry{
+		Mode: FilemodeBlob,
+		Uid:  0,
+		Gid:  0,
+		Size: uint32(len(content)),
+		Id:   id,
+		Path: "README",
+	})
+	checkFatal(t, err)
+
+	treeId, err := idx.WriteTreeTo(repo)
+	checkFatal(t, err)
+
+	if treeId.String() != "b7119b11e8ef7a1a5a34d3ac87f5b075228ac81e" {
+		t.Fatalf("%v", treeId.String())
+	}
+}
+
+func TestIndexAddAndWriteTreeTo(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	odb, err := repo.Odb()
+	checkFatal(t, err)
+
+	blobID, err := odb.Write([]byte("foo\n"), ObjectBlob)
+	checkFatal(t, err)
+
+	idx, err := NewIndex()
+	checkFatal(t, err)
+
+	if idx.Path() != "" {
+		t.Fatal("in-memory repo has a path")
+	}
+
+	entry := IndexEntry{
+		Path: "README",
+		Id:   blobID,
+		Mode: FilemodeBlob,
+	}
+
+	err = idx.Add(&entry)
+	checkFatal(t, err)
+
+	treeId, err := idx.WriteTreeTo(repo)
+	checkFatal(t, err)
+
+	if treeId.String() != "b7119b11e8ef7a1a5a34d3ac87f5b075228ac81e" {
+		t.Fatalf("%v", treeId.String())
+	}
+}
+
+func TestIndexRemoveDirectory(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	odb, err := repo.Odb()
+	checkFatal(t, err)
+
+	blobID, err := odb.Write([]byte("fou\n"), ObjectBlob)
+	checkFatal(t, err)
+
+	idx, err := NewIndex()
+	checkFatal(t, err)
+
+	entryCount := idx.EntryCount()
+	if entryCount != 0 {
+		t.Fatal("Index should count 0 entry")
+	}
+
+	entry := IndexEntry{
+		Path: "path/to/LISEZ_MOI",
+		Id:   blobID,
+		Mode: FilemodeBlob,
+	}
+
+	err = idx.Add(&entry)
+	checkFatal(t, err)
+
+	entryCount = idx.EntryCount()
+	if entryCount != 1 {
+		t.Fatal("Index should count 1 entry")
+	}
+
+	err = idx.RemoveDirectory("path", 0)
+
+	entryCount = idx.EntryCount()
+	if entryCount != 0 {
+		t.Fatal("Index should count 0 entry")
+	}
+}
+
+func TestIndexAddFromBuffer(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+
+	entry := IndexEntry{
+		Path: "README",
+		Mode: FilemodeBlob,
+	}
+
+	err = idx.AddFromBuffer(&entry, []byte("foo\n"))
+	checkFatal(t, err)
+
+	treeId, err := idx.WriteTreeTo(repo)
+	checkFatal(t, err)
+
+	if treeId.String() != "b7119b11e8ef7a1a5a34d3ac87f5b075228ac81e" {
+		t.Fatalf("%v", treeId.String())
+	}
+}
+
+func TestIndexAddAllNoCallback(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	err := ioutil.WriteFile(repo.Workdir()+"/README", []byte("foo\n"), 0644)
+	checkFatal(t, err)
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+
+	err = idx.AddAll([]string{}, IndexAddDefault, nil)
+	checkFatal(t, err)
+
+	treeId, err := idx.WriteTreeTo(repo)
+	checkFatal(t, err)
+
+	if treeId.String() != "b7119b11e8ef7a1a5a34d3ac87f5b075228ac81e" {
+		t.Fatalf("%v", treeId.String())
+	}
+}
+
+func TestIndexAddAllCallback(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	err := ioutil.WriteFile(repo.Workdir()+"/README", []byte("foo\n"), 0644)
+	checkFatal(t, err)
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+
+	cbPath := ""
+	err = idx.AddAll([]string{}, IndexAddDefault, func(p, mP string) error {
+		cbPath = p
+		return nil
+	})
+	checkFatal(t, err)
+	if cbPath != "README" {
+		t.Fatalf("%v", cbPath)
+	}
+
+	treeId, err := idx.WriteTreeTo(repo)
+	checkFatal(t, err)
+
+	if treeId.String() != "b7119b11e8ef7a1a5a34d3ac87f5b075228ac81e" {
+		t.Fatalf("%v", treeId.String())
+	}
+}
+
+func TestIndexOpen(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	path := repo.Workdir() + "/heyindex"
+
+	_, err := os.Stat(path)
+	if !os.IsNotExist(err) {
+		t.Fatal("new index file already exists")
+	}
+
+	idx, err := OpenIndex(path)
+	checkFatal(t, err)
+
+	if path != idx.Path() {
+		t.Fatalf("mismatched index paths, expected %v, got %v", path, idx.Path())
+	}
+
+	err = idx.Write()
+	checkFatal(t, err)
+
+	_, err = os.Stat(path)
+	if os.IsNotExist(err) {
+		t.Fatal("new index file did not get written")
+	}
+}
+
 func checkFatal(t *testing.T, err error) {
 	if err == nil {
 		return
@@ -30,8 +276,7 @@ func checkFatal(t *testing.T, err error) {
 	// The failure happens at wherever we were called, not here
 	_, file, line, ok := runtime.Caller(1)
 	if !ok {
-		t.Fatal()
+		t.Fatalf("Unable to get caller")
 	}
-
 	t.Fatalf("Fail at %v:%v; %v", file, line, err)
 }

indexer.go

@@ -0,0 +1,97 @@
+package git
+
+/*
+#include <git2.h>
+
+extern const git_oid * git_indexer_hash(const git_indexer *idx);
+extern int git_indexer_append(git_indexer *idx, const void *data, size_t size, git_transfer_progress *stats);
+extern int git_indexer_commit(git_indexer *idx, git_transfer_progress *stats);
+extern int _go_git_indexer_new(git_indexer **out, const char *path, unsigned int mode, git_odb *odb, void *progress_cb_payload);
+extern void git_indexer_free(git_indexer *idx);
+*/
+import "C"
+import (
+	"reflect"
+	"runtime"
+	"unsafe"
+)
+
+// Indexer can post-process packfiles and create an .idx file for efficient
+// lookup.
+type Indexer struct {
+	doNotCompare
+	ptr        *C.git_indexer
+	stats      C.git_transfer_progress
+	ccallbacks C.git_remote_callbacks
+}
+
+// NewIndexer creates a new indexer instance.
+func NewIndexer(packfilePath string, odb *Odb, callback TransferProgressCallback) (indexer *Indexer, err error) {
+	var odbPtr *C.git_odb = nil
+	if odb != nil {
+		odbPtr = odb.ptr
+	}
+
+	indexer = new(Indexer)
+	populateRemoteCallbacks(&indexer.ccallbacks, &RemoteCallbacks{TransferProgressCallback: callback}, nil)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cstr := C.CString(packfilePath)
+	defer C.free(unsafe.Pointer(cstr))
+
+	ret := C._go_git_indexer_new(&indexer.ptr, cstr, 0, odbPtr, indexer.ccallbacks.payload)
+	runtime.KeepAlive(odb)
+	if ret < 0 {
+		untrackCallbacksPayload(&indexer.ccallbacks)
+		return nil, MakeGitError(ret)
+	}
+
+	runtime.SetFinalizer(indexer, (*Indexer).Free)
+	return indexer, nil
+}
+
+// Write adds data to the indexer.
+func (indexer *Indexer) Write(data []byte) (int, error) {
+	header := (*reflect.SliceHeader)(unsafe.Pointer(&data))
+	ptr := unsafe.Pointer(header.Data)
+	size := C.size_t(header.Len)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_indexer_append(indexer.ptr, ptr, size, &indexer.stats)
+	runtime.KeepAlive(indexer)
+	if ret < 0 {
+		return 0, MakeGitError(ret)
+	}
+
+	return len(data), nil
+}
+
+// Commit finalizes the pack and index. It resolves any pending deltas and
+// writes out the index file.
+//
+// It also returns the packfile's hash. A packfile's name is derived from the
+// sorted hashing of all object names.
+func (indexer *Indexer) Commit() (*Oid, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_indexer_commit(indexer.ptr, &indexer.stats)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	id := newOidFromC(C.git_indexer_hash(indexer.ptr))
+	runtime.KeepAlive(indexer)
+	return id, nil
+}
+
+// Free frees the indexer and its resources.
+func (indexer *Indexer) Free() {
+	untrackCallbacksPayload(&indexer.ccallbacks)
+	runtime.SetFinalizer(indexer, nil)
+	C.git_indexer_free(indexer.ptr)
+}

indexer_test.go

@@ -0,0 +1,93 @@
+package git
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"testing"
+)
+
+var (
+	// This is a packfile with three objects. The second is a delta which
+	// depends on the third, which is also a delta.
+	outOfOrderPack = []byte{
+		0x50, 0x41, 0x43, 0x4b, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x03,
+		0x32, 0x78, 0x9c, 0x63, 0x67, 0x00, 0x00, 0x00, 0x10, 0x00, 0x08, 0x76,
+		0xe6, 0x8f, 0xe8, 0x12, 0x9b, 0x54, 0x6b, 0x10, 0x1a, 0xee, 0x95, 0x10,
+		0xc5, 0x32, 0x8e, 0x7f, 0x21, 0xca, 0x1d, 0x18, 0x78, 0x9c, 0x63, 0x62,
+		0x66, 0x4e, 0xcb, 0xcf, 0x07, 0x00, 0x02, 0xac, 0x01, 0x4d, 0x75, 0x01,
+		0xd7, 0x71, 0x36, 0x66, 0xf4, 0xde, 0x82, 0x27, 0x76, 0xc7, 0x62, 0x2c,
+		0x10, 0xf1, 0xb0, 0x7d, 0xe2, 0x80, 0xdc, 0x78, 0x9c, 0x63, 0x62, 0x62,
+		0x62, 0xb7, 0x03, 0x00, 0x00, 0x69, 0x00, 0x4c, 0xde, 0x7d, 0xaa, 0xe4,
+		0x19, 0x87, 0x58, 0x80, 0x61, 0x09, 0x9a, 0x33, 0xca, 0x7a, 0x31, 0x92,
+		0x6f, 0xae, 0x66, 0x75,
+	}
+)
+
+func TestIndexerOutOfOrder(t *testing.T) {
+	t.Parallel()
+
+	tmpPath, err := ioutil.TempDir("", "git2go")
+	checkFatal(t, err)
+	defer os.RemoveAll(tmpPath)
+
+	var finalStats TransferProgress
+	idx, err := NewIndexer(tmpPath, nil, func(stats TransferProgress) error {
+		finalStats = stats
+		return nil
+	})
+	checkFatal(t, err)
+	defer idx.Free()
+
+	_, err = idx.Write(outOfOrderPack)
+	checkFatal(t, err)
+	oid, err := idx.Commit()
+	checkFatal(t, err)
+
+	// The packfile contains the hash as the last 20 bytes.
+	expectedOid := NewOidFromBytes(outOfOrderPack[len(outOfOrderPack)-20:])
+	if !expectedOid.Equal(oid) {
+		t.Errorf("mismatched packfile hash, expected %v, got %v", expectedOid, oid)
+	}
+	if finalStats.TotalObjects != 3 {
+		t.Errorf("mismatched transferred objects, expected 3, got %v", finalStats.TotalObjects)
+	}
+	if finalStats.ReceivedObjects != 3 {
+		t.Errorf("mismatched received objects, expected 3, got %v", finalStats.ReceivedObjects)
+	}
+	if finalStats.IndexedObjects != 3 {
+		t.Errorf("mismatched indexed objects, expected 3, got %v", finalStats.IndexedObjects)
+	}
+
+	odb, err := NewOdb()
+	checkFatal(t, err)
+	defer odb.Free()
+
+	backend, err := NewOdbBackendOnePack(path.Join(tmpPath, fmt.Sprintf("pack-%s.idx", oid.String())))
+	checkFatal(t, err)
+	// Transfer the ownership of the backend to the odb, no freeing needed.
+	err = odb.AddBackend(backend, 1)
+	checkFatal(t, err)
+
+	packfileObjects := 0
+	err = odb.ForEach(func(id *Oid) error {
+		packfileObjects += 1
+		return nil
+	})
+	checkFatal(t, err)
+	if packfileObjects != 3 {
+		t.Errorf("mismatched packfile objects, expected 3, got %v", packfileObjects)
+	}
+
+	// Inspect one of the well-known objects in the packfile.
+	obj, err := odb.Read(NewOidFromBytes([]byte{
+		0x19, 0x10, 0x28, 0x15, 0x66, 0x3d, 0x23, 0xf8, 0xb7, 0x5a, 0x47, 0xe7,
+		0xa0, 0x19, 0x65, 0xdc, 0xdc, 0x96, 0x46, 0x8c,
+	}))
+	checkFatal(t, err)
+	defer obj.Free()
+	if "foo" != string(obj.Data()) {
+		t.Errorf("mismatched packfile object contents, expected foo, got %q", string(obj.Data()))
+	}
+}

mempack.go

@@ -0,0 +1,92 @@
+package git
+
+/*
+#include <git2.h>
+#include <git2/sys/mempack.h>
+
+extern int git_mempack_new(git_odb_backend **out);
+extern int git_mempack_dump(git_buf *pack, git_repository *repo, git_odb_backend *backend);
+extern int git_mempack_reset(git_odb_backend *backend);
+extern void _go_git_odb_backend_free(git_odb_backend *backend);
+*/
+import "C"
+
+import (
+	"runtime"
+	"unsafe"
+)
+
+// Mempack is a custom ODB backend that permits packing object in-memory.
+type Mempack struct {
+	doNotCompare
+	ptr *C.git_odb_backend
+}
+
+// NewMempack creates a new mempack instance and registers it to the ODB.
+func NewMempack(odb *Odb) (mempack *Mempack, err error) {
+	mempack = new(Mempack)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_mempack_new(&mempack.ptr)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	ret = C.git_odb_add_backend(odb.ptr, mempack.ptr, C.int(999))
+	runtime.KeepAlive(odb)
+	if ret < 0 {
+		// Since git_odb_add_alternate() takes ownership of the ODB backend, the
+		// only case in which we free the mempack's memory is if it fails to be
+		// added to the ODB.
+		C._go_git_odb_backend_free(mempack.ptr)
+		return nil, MakeGitError(ret)
+	}
+
+	return mempack, nil
+}
+
+// Dump dumps all the queued in-memory writes to a packfile.
+//
+// It is the caller's responsibility to ensure that the generated packfile is
+// available to the repository (e.g. by writing it to disk, or doing something
+// crazy like distributing it across several copies of the repository over a
+// network).
+//
+// Once the generated packfile is available to the repository, call
+// Mempack.Reset to cleanup the memory store.
+//
+// Calling Mempack.Reset before the packfile has been written to disk will
+// result in an inconsistent repository (the objects in the memory store won't
+// be accessible).
+func (mempack *Mempack) Dump(repository *Repository) ([]byte, error) {
+	buf := C.git_buf{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_mempack_dump(&buf, repository.ptr, mempack.ptr)
+	runtime.KeepAlive(repository)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	defer C.git_buf_dispose(&buf)
+
+	return C.GoBytes(unsafe.Pointer(buf.ptr), C.int(buf.size)), nil
+}
+
+// Reset resets the memory packer by clearing all the queued objects.
+//
+// This assumes that Mempack.Dump has been called before to store all the
+// queued objects into a single packfile.
+func (mempack *Mempack) Reset() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_mempack_reset(mempack.ptr)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}

mempack_test.go

@@ -0,0 +1,60 @@
+package git
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestMempack(t *testing.T) {
+	t.Parallel()
+
+	odb, err := NewOdb()
+	checkFatal(t, err)
+
+	repo, err := NewRepositoryWrapOdb(odb)
+	checkFatal(t, err)
+
+	mempack, err := NewMempack(odb)
+	checkFatal(t, err)
+
+	id, err := odb.Write([]byte("hello, world!"), ObjectBlob)
+	checkFatal(t, err)
+
+	expectedId, err := NewOid("30f51a3fba5274d53522d0f19748456974647b4f")
+	checkFatal(t, err)
+	if !expectedId.Equal(id) {
+		t.Errorf("mismatched id. expected %v, got %v", expectedId.String(), id.String())
+	}
+
+	// The object should be available from the odb.
+	{
+		obj, err := odb.Read(expectedId)
+		checkFatal(t, err)
+		defer obj.Free()
+	}
+
+	data, err := mempack.Dump(repo)
+	checkFatal(t, err)
+
+	expectedData := []byte{
+		0x50, 0x41, 0x43, 0x4b, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00,
+		0x02, 0x9d, 0x08, 0x82, 0x3b, 0xd8, 0xa8, 0xea, 0xb5, 0x10, 0xad, 0x6a,
+		0xc7, 0x5c, 0x82, 0x3c, 0xfd, 0x3e, 0xd3, 0x1e,
+	}
+	if !bytes.Equal(expectedData, data) {
+		t.Errorf("mismatched mempack data. expected %v, got %v", expectedData, data)
+	}
+
+	mempack.Reset()
+
+	// After the reset, the object should now be unavailable.
+	{
+		obj, err := odb.Read(expectedId)
+		if err == nil {
+			t.Errorf("object %s unexpectedly found", obj.Id().String())
+			obj.Free()
+		} else if !IsErrorCode(err, ErrorCodeNotFound) {
+			t.Errorf("unexpected error %v", err)
+		}
+	}
+}

merge.go

@@ -0,0 +1,596 @@
+package git
+
+/*
+#include <git2.h>
+
+extern git_annotated_commit** _go_git_make_merge_head_array(size_t len);
+extern void _go_git_annotated_commit_array_set(git_annotated_commit** array, git_annotated_commit* ptr, size_t n);
+extern git_annotated_commit* _go_git_annotated_commit_array_get(git_annotated_commit** array, size_t n);
+extern int _go_git_merge_file(git_merge_file_result*, char*, size_t, char*, unsigned int, char*, size_t, char*, unsigned int, char*, size_t, char*, unsigned int, git_merge_file_options*);
+
+*/
+import "C"
+import (
+	"reflect"
+	"runtime"
+	"unsafe"
+)
+
+type AnnotatedCommit struct {
+	doNotCompare
+	ptr *C.git_annotated_commit
+	r   *Repository
+}
+
+func newAnnotatedCommitFromC(ptr *C.git_annotated_commit, r *Repository) *AnnotatedCommit {
+	mh := &AnnotatedCommit{ptr: ptr, r: r}
+	runtime.SetFinalizer(mh, (*AnnotatedCommit).Free)
+	return mh
+}
+
+func (mh *AnnotatedCommit) Id() *Oid {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := newOidFromC(C.git_annotated_commit_id(mh.ptr))
+	runtime.KeepAlive(mh)
+	return ret
+}
+
+func (mh *AnnotatedCommit) Free() {
+	runtime.SetFinalizer(mh, nil)
+	C.git_annotated_commit_free(mh.ptr)
+}
+
+func (r *Repository) AnnotatedCommitFromFetchHead(branchName string, remoteURL string, oid *Oid) (*AnnotatedCommit, error) {
+	cbranchName := C.CString(branchName)
+	defer C.free(unsafe.Pointer(cbranchName))
+
+	cremoteURL := C.CString(remoteURL)
+	defer C.free(unsafe.Pointer(cremoteURL))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_annotated_commit
+	ret := C.git_annotated_commit_from_fetchhead(&ptr, r.ptr, cbranchName, cremoteURL, oid.toC())
+	runtime.KeepAlive(oid)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	annotatedCommit := newAnnotatedCommitFromC(ptr, r)
+	runtime.KeepAlive(r)
+	return annotatedCommit, nil
+}
+
+func (r *Repository) LookupAnnotatedCommit(oid *Oid) (*AnnotatedCommit, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_annotated_commit
+	ret := C.git_annotated_commit_lookup(&ptr, r.ptr, oid.toC())
+	runtime.KeepAlive(oid)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	annotatedCommit := newAnnotatedCommitFromC(ptr, r)
+	runtime.KeepAlive(r)
+	return annotatedCommit, nil
+}
+
+func (r *Repository) AnnotatedCommitFromRef(ref *Reference) (*AnnotatedCommit, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_annotated_commit
+	ret := C.git_annotated_commit_from_ref(&ptr, r.ptr, ref.ptr)
+	runtime.KeepAlive(r)
+	runtime.KeepAlive(ref)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	annotatedCommit := newAnnotatedCommitFromC(ptr, r)
+	runtime.KeepAlive(r)
+	return annotatedCommit, nil
+}
+
+func (r *Repository) AnnotatedCommitFromRevspec(spec string) (*AnnotatedCommit, error) {
+	crevspec := C.CString(spec)
+	defer C.free(unsafe.Pointer(crevspec))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_annotated_commit
+	ret := C.git_annotated_commit_from_revspec(&ptr, r.ptr, crevspec)
+	runtime.KeepAlive(r)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	annotatedCommit := newAnnotatedCommitFromC(ptr, r)
+	runtime.KeepAlive(r)
+	return annotatedCommit, nil
+}
+
+type MergeTreeFlag int
+
+const (
+	// Detect renames that occur between the common ancestor and the "ours"
+	// side or the common ancestor and the "theirs" side.  This will enable
+	// the ability to merge between a modified and renamed file.
+	MergeTreeFindRenames MergeTreeFlag = C.GIT_MERGE_FIND_RENAMES
+	// If a conflict occurs, exit immediately instead of attempting to
+	// continue resolving conflicts.  The merge operation will fail with
+	// GIT_EMERGECONFLICT and no index will be returned.
+	MergeTreeFailOnConflict MergeTreeFlag = C.GIT_MERGE_FAIL_ON_CONFLICT
+	// MergeTreeSkipREUC specifies not to write the REUC extension on the
+	// generated index.
+	MergeTreeSkipREUC MergeTreeFlag = C.GIT_MERGE_SKIP_REUC
+	// MergeTreeNoRecursive specifies not to build a recursive merge base (by
+	// merging the multiple merge bases) if the commits being merged have
+	// multiple merge bases. Instead, the first base is used.
+	// This flag provides a similar merge base to `git-merge-resolve`.
+	MergeTreeNoRecursive MergeTreeFlag = C.GIT_MERGE_NO_RECURSIVE
+)
+
+type MergeOptions struct {
+	TreeFlags MergeTreeFlag
+
+	RenameThreshold uint
+	TargetLimit     uint
+	RecursionLimit  uint
+	FileFavor       MergeFileFavor
+
+	//TODO: Diff similarity metric
+}
+
+func mergeOptionsFromC(opts *C.git_merge_options) MergeOptions {
+	return MergeOptions{
+		TreeFlags:       MergeTreeFlag(opts.flags),
+		RenameThreshold: uint(opts.rename_threshold),
+		TargetLimit:     uint(opts.target_limit),
+		RecursionLimit:  uint(opts.recursion_limit),
+		FileFavor:       MergeFileFavor(opts.file_favor),
+	}
+}
+
+func DefaultMergeOptions() (MergeOptions, error) {
+	opts := C.git_merge_options{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_merge_options_init(&opts, C.GIT_MERGE_OPTIONS_VERSION)
+	if ecode < 0 {
+		return MergeOptions{}, MakeGitError(ecode)
+	}
+	return mergeOptionsFromC(&opts), nil
+}
+
+func populateMergeOptions(copts *C.git_merge_options, opts *MergeOptions) *C.git_merge_options {
+	C.git_merge_options_init(copts, C.GIT_MERGE_OPTIONS_VERSION)
+	if opts == nil {
+		return nil
+	}
+	copts.flags = C.uint32_t(opts.TreeFlags)
+	copts.rename_threshold = C.uint(opts.RenameThreshold)
+	copts.target_limit = C.uint(opts.TargetLimit)
+	copts.recursion_limit = C.uint(opts.RecursionLimit)
+	copts.file_favor = C.git_merge_file_favor_t(opts.FileFavor)
+	return copts
+}
+
+func freeMergeOptions(copts *C.git_merge_options) {
+}
+
+type MergeFileFavor int
+
+const (
+	MergeFileFavorNormal MergeFileFavor = C.GIT_MERGE_FILE_FAVOR_NORMAL
+	MergeFileFavorOurs   MergeFileFavor = C.GIT_MERGE_FILE_FAVOR_OURS
+	MergeFileFavorTheirs MergeFileFavor = C.GIT_MERGE_FILE_FAVOR_THEIRS
+	MergeFileFavorUnion  MergeFileFavor = C.GIT_MERGE_FILE_FAVOR_UNION
+)
+
+func (r *Repository) Merge(theirHeads []*AnnotatedCommit, mergeOptions *MergeOptions, checkoutOptions *CheckoutOptions) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var err error
+	cMergeOpts := populateMergeOptions(&C.git_merge_options{}, mergeOptions)
+	defer freeMergeOptions(cMergeOpts)
+	cCheckoutOptions := populateCheckoutOptions(&C.git_checkout_options{}, checkoutOptions, &err)
+	defer freeCheckoutOptions(cCheckoutOptions)
+
+	gmerge_head_array := make([]*C.git_annotated_commit, len(theirHeads))
+	for i := 0; i < len(theirHeads); i++ {
+		gmerge_head_array[i] = theirHeads[i].ptr
+	}
+	ptr := unsafe.Pointer(&gmerge_head_array[0])
+	ret := C.git_merge(r.ptr, (**C.git_annotated_commit)(ptr), C.size_t(len(theirHeads)), cMergeOpts, cCheckoutOptions)
+	runtime.KeepAlive(theirHeads)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+type MergeAnalysis int
+
+const (
+	MergeAnalysisNone        MergeAnalysis = C.GIT_MERGE_ANALYSIS_NONE
+	MergeAnalysisNormal      MergeAnalysis = C.GIT_MERGE_ANALYSIS_NORMAL
+	MergeAnalysisUpToDate    MergeAnalysis = C.GIT_MERGE_ANALYSIS_UP_TO_DATE
+	MergeAnalysisFastForward MergeAnalysis = C.GIT_MERGE_ANALYSIS_FASTFORWARD
+	MergeAnalysisUnborn      MergeAnalysis = C.GIT_MERGE_ANALYSIS_UNBORN
+)
+
+type MergePreference int
+
+const (
+	MergePreferenceNone            MergePreference = C.GIT_MERGE_PREFERENCE_NONE
+	MergePreferenceNoFastForward   MergePreference = C.GIT_MERGE_PREFERENCE_NO_FASTFORWARD
+	MergePreferenceFastForwardOnly MergePreference = C.GIT_MERGE_PREFERENCE_FASTFORWARD_ONLY
+)
+
+// MergeAnalysis returns the possible actions which could be taken by
+// a 'git-merge' command. There may be multiple answers, so the first
+// return value is a bitmask of MergeAnalysis values.
+func (r *Repository) MergeAnalysis(theirHeads []*AnnotatedCommit) (MergeAnalysis, MergePreference, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	gmerge_head_array := make([]*C.git_annotated_commit, len(theirHeads))
+	for i := 0; i < len(theirHeads); i++ {
+		gmerge_head_array[i] = theirHeads[i].ptr
+	}
+	ptr := unsafe.Pointer(&gmerge_head_array[0])
+	var analysis C.git_merge_analysis_t
+	var preference C.git_merge_preference_t
+	err := C.git_merge_analysis(&analysis, &preference, r.ptr, (**C.git_annotated_commit)(ptr), C.size_t(len(theirHeads)))
+	runtime.KeepAlive(theirHeads)
+	if err < 0 {
+		return MergeAnalysisNone, MergePreferenceNone, MakeGitError(err)
+	}
+	return MergeAnalysis(analysis), MergePreference(preference), nil
+
+}
+
+func (r *Repository) MergeCommits(ours *Commit, theirs *Commit, options *MergeOptions) (*Index, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	copts := populateMergeOptions(&C.git_merge_options{}, options)
+	defer freeMergeOptions(copts)
+
+	var ptr *C.git_index
+	ret := C.git_merge_commits(&ptr, r.ptr, ours.cast_ptr, theirs.cast_ptr, copts)
+	runtime.KeepAlive(ours)
+	runtime.KeepAlive(theirs)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newIndexFromC(ptr, r), nil
+}
+
+func (r *Repository) MergeTrees(ancestor *Tree, ours *Tree, theirs *Tree, options *MergeOptions) (*Index, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	copts := populateMergeOptions(&C.git_merge_options{}, options)
+	defer freeMergeOptions(copts)
+
+	var ancestor_ptr *C.git_tree
+	if ancestor != nil {
+		ancestor_ptr = ancestor.cast_ptr
+	}
+	var ptr *C.git_index
+	ret := C.git_merge_trees(&ptr, r.ptr, ancestor_ptr, ours.cast_ptr, theirs.cast_ptr, copts)
+	runtime.KeepAlive(ancestor)
+	runtime.KeepAlive(ours)
+	runtime.KeepAlive(theirs)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newIndexFromC(ptr, r), nil
+}
+
+func (r *Repository) MergeBase(one *Oid, two *Oid) (*Oid, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var oid C.git_oid
+	ret := C.git_merge_base(&oid, r.ptr, one.toC(), two.toC())
+	runtime.KeepAlive(one)
+	runtime.KeepAlive(two)
+	runtime.KeepAlive(r)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return newOidFromC(&oid), nil
+}
+
+// MergeBases retrieves the list of merge bases between two commits.
+//
+// If none are found, an empty slice is returned and the error is set
+// approprately
+func (r *Repository) MergeBases(one, two *Oid) ([]*Oid, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var coids C.git_oidarray
+	ret := C.git_merge_bases(&coids, r.ptr, one.toC(), two.toC())
+	runtime.KeepAlive(one)
+	runtime.KeepAlive(two)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	oids := make([]*Oid, coids.count)
+	hdr := reflect.SliceHeader{
+		Data: uintptr(unsafe.Pointer(coids.ids)),
+		Len:  int(coids.count),
+		Cap:  int(coids.count),
+	}
+
+	goSlice := *(*[]C.git_oid)(unsafe.Pointer(&hdr))
+
+	for i, cid := range goSlice {
+		oids[i] = newOidFromC(&cid)
+	}
+
+	return oids, nil
+}
+
+// MergeBaseMany finds a merge base given a list of commits.
+func (r *Repository) MergeBaseMany(oids []*Oid) (*Oid, error) {
+	coids := make([]C.git_oid, len(oids))
+	for i := 0; i < len(oids); i++ {
+		coids[i] = *oids[i].toC()
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var oid C.git_oid
+	ret := C.git_merge_base_many(&oid, r.ptr, C.size_t(len(oids)), &coids[0])
+	runtime.KeepAlive(r)
+	runtime.KeepAlive(coids)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return newOidFromC(&oid), nil
+}
+
+// MergeBasesMany finds all merge bases given a list of commits.
+func (r *Repository) MergeBasesMany(oids []*Oid) ([]*Oid, error) {
+	inCoids := make([]C.git_oid, len(oids))
+	for i := 0; i < len(oids); i++ {
+		inCoids[i] = *oids[i].toC()
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var outCoids C.git_oidarray
+	ret := C.git_merge_bases_many(&outCoids, r.ptr, C.size_t(len(oids)), &inCoids[0])
+	runtime.KeepAlive(r)
+	runtime.KeepAlive(inCoids)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	outOids := make([]*Oid, outCoids.count)
+	hdr := reflect.SliceHeader{
+		Data: uintptr(unsafe.Pointer(outCoids.ids)),
+		Len:  int(outCoids.count),
+		Cap:  int(outCoids.count),
+	}
+	goSlice := *(*[]C.git_oid)(unsafe.Pointer(&hdr))
+
+	for i, cid := range goSlice {
+		outOids[i] = newOidFromC(&cid)
+	}
+
+	return outOids, nil
+}
+
+// MergeBaseOctopus finds a merge base in preparation for an octopus merge.
+func (r *Repository) MergeBaseOctopus(oids []*Oid) (*Oid, error) {
+	coids := make([]C.git_oid, len(oids))
+	for i := 0; i < len(oids); i++ {
+		coids[i] = *oids[i].toC()
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var oid C.git_oid
+	ret := C.git_merge_base_octopus(&oid, r.ptr, C.size_t(len(oids)), &coids[0])
+	runtime.KeepAlive(r)
+	runtime.KeepAlive(coids)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return newOidFromC(&oid), nil
+}
+
+type MergeFileResult struct {
+	doNotCompare
+	ptr           *C.git_merge_file_result
+	Automergeable bool
+	Path          string
+	Mode          uint
+	Contents      []byte
+}
+
+func newMergeFileResultFromC(c *C.git_merge_file_result) *MergeFileResult {
+	var path string
+	if c.path != nil {
+		path = C.GoString(c.path)
+	}
+
+	originalBytes := C.GoBytes(unsafe.Pointer(c.ptr), C.int(c.len))
+	gobytes := make([]byte, len(originalBytes))
+	copy(gobytes, originalBytes)
+	r := &MergeFileResult{
+		Automergeable: c.automergeable != 0,
+		Path:          path,
+		Mode:          uint(c.mode),
+		Contents:      gobytes,
+		ptr:           c,
+	}
+
+	runtime.SetFinalizer(r, (*MergeFileResult).Free)
+	return r
+}
+
+func (r *MergeFileResult) Free() {
+	runtime.SetFinalizer(r, nil)
+	C.git_merge_file_result_free(r.ptr)
+}
+
+type MergeFileInput struct {
+	Path     string
+	Mode     uint
+	Contents []byte
+}
+
+type MergeFileFlags int
+
+const (
+	MergeFileDefault MergeFileFlags = C.GIT_MERGE_FILE_DEFAULT
+
+	// Create standard conflicted merge files
+	MergeFileStyleMerge MergeFileFlags = C.GIT_MERGE_FILE_STYLE_MERGE
+
+	// Create diff3-style files
+	MergeFileStyleDiff MergeFileFlags = C.GIT_MERGE_FILE_STYLE_DIFF3
+
+	// Condense non-alphanumeric regions for simplified diff file
+	MergeFileStyleSimplifyAlnum MergeFileFlags = C.GIT_MERGE_FILE_SIMPLIFY_ALNUM
+
+	// Ignore all whitespace
+	MergeFileIgnoreWhitespace MergeFileFlags = C.GIT_MERGE_FILE_IGNORE_WHITESPACE
+
+	// Ignore changes in amount of whitespace
+	MergeFileIgnoreWhitespaceChange MergeFileFlags = C.GIT_MERGE_FILE_IGNORE_WHITESPACE_CHANGE
+
+	// Ignore whitespace at end of line
+	MergeFileIgnoreWhitespaceEOL MergeFileFlags = C.GIT_MERGE_FILE_IGNORE_WHITESPACE_EOL
+
+	// Use the "patience diff" algorithm
+	MergeFileDiffPatience MergeFileFlags = C.GIT_MERGE_FILE_DIFF_PATIENCE
+
+	// Take extra time to find minimal diff
+	MergeFileDiffMinimal MergeFileFlags = C.GIT_MERGE_FILE_DIFF_MINIMAL
+)
+
+type MergeFileOptions struct {
+	AncestorLabel string
+	OurLabel      string
+	TheirLabel    string
+	Favor         MergeFileFavor
+	Flags         MergeFileFlags
+	MarkerSize    uint16
+}
+
+func mergeFileOptionsFromC(c C.git_merge_file_options) MergeFileOptions {
+	return MergeFileOptions{
+		AncestorLabel: C.GoString(c.ancestor_label),
+		OurLabel:      C.GoString(c.our_label),
+		TheirLabel:    C.GoString(c.their_label),
+		Favor:         MergeFileFavor(c.favor),
+		Flags:         MergeFileFlags(c.flags),
+		MarkerSize:    uint16(c.marker_size),
+	}
+}
+
+func populateMergeFileOptions(copts *C.git_merge_file_options, opts *MergeFileOptions) *C.git_merge_file_options {
+	C.git_merge_file_options_init(copts, C.GIT_MERGE_FILE_OPTIONS_VERSION)
+	if opts == nil {
+		return nil
+	}
+
+	copts.ancestor_label = C.CString(opts.AncestorLabel)
+	copts.our_label = C.CString(opts.OurLabel)
+	copts.their_label = C.CString(opts.TheirLabel)
+	copts.favor = C.git_merge_file_favor_t(opts.Favor)
+	copts.flags = C.uint32_t(opts.Flags)
+	copts.marker_size = C.ushort(opts.MarkerSize)
+	return copts
+}
+
+func freeMergeFileOptions(copts *C.git_merge_file_options) {
+	if copts == nil {
+		return
+	}
+	C.free(unsafe.Pointer(copts.ancestor_label))
+	C.free(unsafe.Pointer(copts.our_label))
+	C.free(unsafe.Pointer(copts.their_label))
+}
+
+func MergeFile(ancestor MergeFileInput, ours MergeFileInput, theirs MergeFileInput, options *MergeFileOptions) (*MergeFileResult, error) {
+
+	ancestorPath := C.CString(ancestor.Path)
+	defer C.free(unsafe.Pointer(ancestorPath))
+	var ancestorContents *byte
+	if len(ancestor.Contents) > 0 {
+		ancestorContents = &ancestor.Contents[0]
+	}
+
+	oursPath := C.CString(ours.Path)
+	defer C.free(unsafe.Pointer(oursPath))
+	var oursContents *byte
+	if len(ours.Contents) > 0 {
+		oursContents = &ours.Contents[0]
+	}
+
+	theirsPath := C.CString(theirs.Path)
+	defer C.free(unsafe.Pointer(theirsPath))
+	var theirsContents *byte
+	if len(theirs.Contents) > 0 {
+		theirsContents = &theirs.Contents[0]
+	}
+
+	var copts *C.git_merge_file_options
+	if options != nil {
+		copts = &C.git_merge_file_options{}
+		ecode := C.git_merge_file_options_init(copts, C.GIT_MERGE_FILE_OPTIONS_VERSION)
+		if ecode < 0 {
+			return nil, MakeGitError(ecode)
+		}
+		populateMergeFileOptions(copts, options)
+		defer freeMergeFileOptions(copts)
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var result C.git_merge_file_result
+	ecode := C._go_git_merge_file(&result,
+		(*C.char)(unsafe.Pointer(ancestorContents)), C.size_t(len(ancestor.Contents)), ancestorPath, C.uint(ancestor.Mode),
+		(*C.char)(unsafe.Pointer(oursContents)), C.size_t(len(ours.Contents)), oursPath, C.uint(ours.Mode),
+		(*C.char)(unsafe.Pointer(theirsContents)), C.size_t(len(theirs.Contents)), theirsPath, C.uint(theirs.Mode),
+		copts)
+	runtime.KeepAlive(ancestor)
+	runtime.KeepAlive(ours)
+	runtime.KeepAlive(theirs)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newMergeFileResultFromC(&result), nil
+
+}
+
+// TODO: GIT_EXTERN(int) git_merge_file_from_index(git_merge_file_result *out,git_repository *repo,const git_index_entry *ancestor,	const git_index_entry *ours,	const git_index_entry *theirs,	const git_merge_file_options *opts);

merge_test.go

@@ -0,0 +1,254 @@
+package git
+
+import (
+	"testing"
+	"time"
+)
+
+func TestAnnotatedCommitFromRevspec(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	mergeHead, err := repo.AnnotatedCommitFromRevspec("refs/heads/master")
+	checkFatal(t, err)
+
+	expectedId := "473bf778b67b6d53e2ab289e0f1a2e8addef2fc2"
+	if mergeHead.Id().String() != expectedId {
+		t.Errorf("mergeHead.Id() = %v, want %v", mergeHead.Id(), expectedId)
+	}
+}
+
+func TestMergeWithSelf(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	master, err := repo.References.Lookup("refs/heads/master")
+	checkFatal(t, err)
+
+	mergeHead, err := repo.AnnotatedCommitFromRef(master)
+	checkFatal(t, err)
+
+	expectedId := "473bf778b67b6d53e2ab289e0f1a2e8addef2fc2"
+	if mergeHead.Id().String() != expectedId {
+		t.Errorf("mergeHead.Id() = %v, want %v", mergeHead.Id(), expectedId)
+	}
+
+	mergeHeads := make([]*AnnotatedCommit, 1)
+	mergeHeads[0] = mergeHead
+	err = repo.Merge(mergeHeads, nil, nil)
+	checkFatal(t, err)
+
+	mergeMessage, err := repo.Message()
+	checkFatal(t, err)
+
+	expectedMessage := "Merge branch 'master'\n"
+	if mergeMessage != expectedMessage {
+		t.Errorf("merge Message = %v, want %v", mergeMessage, expectedMessage)
+	}
+}
+
+func TestMergeAnalysisWithSelf(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	master, err := repo.References.Lookup("refs/heads/master")
+	checkFatal(t, err)
+
+	mergeHead, err := repo.AnnotatedCommitFromRef(master)
+	checkFatal(t, err)
+
+	mergeHeads := make([]*AnnotatedCommit, 1)
+	mergeHeads[0] = mergeHead
+	a, _, err := repo.MergeAnalysis(mergeHeads)
+	checkFatal(t, err)
+
+	if a != MergeAnalysisUpToDate {
+		t.Fatalf("Expected up to date merge, not %v", a)
+	}
+}
+
+func TestMergeSameFile(t *testing.T) {
+	t.Parallel()
+	file := MergeFileInput{
+		Path:     "test",
+		Mode:     33188,
+		Contents: []byte("hello world"),
+	}
+
+	result, err := MergeFile(file, file, file, nil)
+	checkFatal(t, err)
+	if !result.Automergeable {
+		t.Fatal("expected automergeable")
+	}
+	if result.Path != file.Path {
+		t.Fatal("path was incorrect")
+	}
+	if result.Mode != file.Mode {
+		t.Fatal("mode was incorrect")
+	}
+
+	compareBytes(t, file.Contents, result.Contents)
+
+}
+func TestMergeTreesWithoutAncestor(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, originalTreeId := seedTestRepo(t, repo)
+	originalTree, err := repo.LookupTree(originalTreeId)
+
+	checkFatal(t, err)
+
+	_, newTreeId := updateReadme(t, repo, "file changed\n")
+
+	newTree, err := repo.LookupTree(newTreeId)
+	checkFatal(t, err)
+	index, err := repo.MergeTrees(nil, originalTree, newTree, nil)
+	if !index.HasConflicts() {
+		t.Fatal("expected conflicts in the index")
+	}
+	_, err = index.Conflict("README")
+	checkFatal(t, err)
+
+}
+
+func appendCommit(t *testing.T, repo *Repository) (*Oid, *Oid) {
+	loc, err := time.LoadLocation("Europe/Berlin")
+	checkFatal(t, err)
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Date(2013, 03, 06, 14, 30, 0, 0, loc),
+	}
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+	err = idx.AddByPath("README")
+	checkFatal(t, err)
+	treeId, err := idx.WriteTree()
+	checkFatal(t, err)
+
+	message := "This is another commit\n"
+	tree, err := repo.LookupTree(treeId)
+	checkFatal(t, err)
+
+	ref, err := repo.References.Lookup("HEAD")
+	checkFatal(t, err)
+
+	parent, err := ref.Peel(ObjectCommit)
+	checkFatal(t, err)
+
+	parentCommit, err := parent.AsCommit()
+	checkFatal(t, err)
+
+	commitId, err := repo.CreateCommit("HEAD", sig, sig, message, tree, parentCommit)
+	checkFatal(t, err)
+
+	return commitId, treeId
+}
+
+func TestMergeBase(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitAId, _ := seedTestRepo(t, repo)
+	commitBId, _ := appendCommit(t, repo)
+
+	mergeBase, err := repo.MergeBase(commitAId, commitBId)
+	checkFatal(t, err)
+
+	if mergeBase.Cmp(commitAId) != 0 {
+		t.Fatalf("unexpected merge base")
+	}
+}
+
+func TestMergeBases(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitAId, _ := seedTestRepo(t, repo)
+	commitBId, _ := appendCommit(t, repo)
+
+	mergeBases, err := repo.MergeBases(commitAId, commitBId)
+	checkFatal(t, err)
+
+	if len(mergeBases) != 1 {
+		t.Fatalf("expected merge bases len to be 1, got %v", len(mergeBases))
+	}
+
+	if mergeBases[0].Cmp(commitAId) != 0 {
+		t.Fatalf("unexpected merge base")
+	}
+}
+
+func TestMergeBaseMany(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitAId, _ := seedTestRepo(t, repo)
+	commitBId, _ := appendCommit(t, repo)
+
+	mergeBase, err := repo.MergeBaseMany([]*Oid{commitAId, commitBId})
+	checkFatal(t, err)
+
+	if mergeBase.Cmp(commitAId) != 0 {
+		t.Fatalf("unexpected merge base")
+	}
+}
+
+func TestMergeBasesMany(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitAId, _ := seedTestRepo(t, repo)
+	commitBId, _ := appendCommit(t, repo)
+
+	mergeBases, err := repo.MergeBasesMany([]*Oid{commitAId, commitBId})
+	checkFatal(t, err)
+
+	if len(mergeBases) != 1 {
+		t.Fatalf("expected merge bases len to be 1, got %v", len(mergeBases))
+	}
+
+	if mergeBases[0].Cmp(commitAId) != 0 {
+		t.Fatalf("unexpected merge base")
+	}
+}
+
+func TestMergeBaseOctopus(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitAId, _ := seedTestRepo(t, repo)
+	commitBId, _ := appendCommit(t, repo)
+
+	mergeBase, err := repo.MergeBaseOctopus([]*Oid{commitAId, commitBId})
+	checkFatal(t, err)
+
+	if mergeBase.Cmp(commitAId) != 0 {
+		t.Fatalf("unexpected merge base")
+	}
+}
+
+func compareBytes(t *testing.T, expected, actual []byte) {
+	for i, v := range expected {
+		if actual[i] != v {
+			t.Fatalf("Bad bytes")
+		}
+	}
+}

message.go

@@ -0,0 +1,42 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+// Trailer represents a single git message trailer.
+type Trailer struct {
+	Key   string
+	Value string
+}
+
+// MessageTrailers parses trailers out of a message, returning a slice of
+// Trailer structs. Trailers are key/value pairs in the last paragraph of a
+// message, not including any patches or conflicts that may be present.
+func MessageTrailers(message string) ([]Trailer, error) {
+	var trailersC C.git_message_trailer_array
+
+	messageC := C.CString(message)
+	defer C.free(unsafe.Pointer(messageC))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_message_trailers(&trailersC, messageC)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+	defer C.git_message_trailer_array_free(&trailersC)
+	trailers := make([]Trailer, trailersC.count)
+	var trailer *C.git_message_trailer
+	for i, p := 0, uintptr(unsafe.Pointer(trailersC.trailers)); i < int(trailersC.count); i, p = i+1, p+unsafe.Sizeof(C.git_message_trailer{}) {
+		trailer = (*C.git_message_trailer)(unsafe.Pointer(p))
+		trailers[i] = Trailer{Key: C.GoString(trailer.key), Value: C.GoString(trailer.value)}
+	}
+	return trailers, nil
+}

message_test.go

@@ -0,0 +1,42 @@
+package git
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestTrailers(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		input    string
+		expected []Trailer
+	}{
+		{
+			"commit with zero trailers\n",
+			[]Trailer{},
+		},
+		{
+			"commit with one trailer\n\nCo-authored-by: Alice <alice@example.com>\n",
+			[]Trailer{
+				Trailer{Key: "Co-authored-by", Value: "Alice <alice@example.com>"},
+			},
+		},
+		{
+			"commit with two trailers\n\nCo-authored-by: Alice <alice@example.com>\nSigned-off-by: Bob <bob@example.com>\n",
+			[]Trailer{
+				Trailer{Key: "Co-authored-by", Value: "Alice <alice@example.com>"},
+				Trailer{Key: "Signed-off-by", Value: "Bob <bob@example.com>"}},
+		},
+	}
+	for _, test := range tests {
+		fmt.Printf("%s", test.input)
+		actual, err := MessageTrailers(test.input)
+		if err != nil {
+			t.Errorf("Trailers returned an unexpected error: %v", err)
+		}
+		if !reflect.DeepEqual(test.expected, actual) {
+			t.Errorf("expecting %#v\ngot %#v", test.expected, actual)
+		}
+	}
+}

note.go

@@ -0,0 +1,247 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+
+import (
+	"runtime"
+	"unsafe"
+)
+
+// This object represents the possible operations which can be
+// performed on the collection of notes for a repository.
+type NoteCollection struct {
+	doNotCompare
+	repo *Repository
+}
+
+// Create adds a note for an object
+func (c *NoteCollection) Create(
+	ref string, author, committer *Signature, id *Oid,
+	note string, force bool) (*Oid, error) {
+
+	oid := new(Oid)
+
+	var cref *C.char
+	if ref == "" {
+		cref = nil
+	} else {
+		cref = C.CString(ref)
+		defer C.free(unsafe.Pointer(cref))
+	}
+
+	authorSig, err := author.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(authorSig)
+
+	committerSig, err := committer.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(committerSig)
+
+	cnote := C.CString(note)
+	defer C.free(unsafe.Pointer(cnote))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_note_create(
+		oid.toC(), c.repo.ptr, cref, authorSig,
+		committerSig, id.toC(), cnote, cbool(force))
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(id)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return oid, nil
+}
+
+// Read reads the note for an object
+func (c *NoteCollection) Read(ref string, id *Oid) (*Note, error) {
+	var cref *C.char
+	if ref == "" {
+		cref = nil
+	} else {
+		cref = C.CString(ref)
+		defer C.free(unsafe.Pointer(cref))
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_note
+	ret := C.git_note_read(&ptr, c.repo.ptr, cref, id.toC())
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(id)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newNoteFromC(ptr, c.repo), nil
+}
+
+// Remove removes the note for an object
+func (c *NoteCollection) Remove(ref string, author, committer *Signature, id *Oid) error {
+	var cref *C.char
+	if ref == "" {
+		cref = nil
+	} else {
+		cref = C.CString(ref)
+		defer C.free(unsafe.Pointer(cref))
+	}
+
+	authorSig, err := author.toC()
+	if err != nil {
+		return err
+	}
+	defer C.git_signature_free(authorSig)
+
+	committerSig, err := committer.toC()
+	if err != nil {
+		return err
+	}
+	defer C.git_signature_free(committerSig)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_note_remove(c.repo.ptr, cref, authorSig, committerSig, id.toC())
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(id)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+// DefaultRef returns the default notes reference for a repository
+func (c *NoteCollection) DefaultRef() (string, error) {
+	buf := C.git_buf{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_note_default_ref(&buf, c.repo.ptr)
+	runtime.KeepAlive(c)
+	if ecode < 0 {
+		return "", MakeGitError(ecode)
+	}
+
+	ret := C.GoString(buf.ptr)
+	C.git_buf_dispose(&buf)
+
+	return ret, nil
+}
+
+// Note
+type Note struct {
+	doNotCompare
+	ptr *C.git_note
+	r   *Repository
+}
+
+func newNoteFromC(ptr *C.git_note, r *Repository) *Note {
+	note := &Note{ptr: ptr, r: r}
+	runtime.SetFinalizer(note, (*Note).Free)
+	return note
+}
+
+// Free frees a git_note object
+func (n *Note) Free() error {
+	if n.ptr == nil {
+		return ErrInvalid
+	}
+	runtime.SetFinalizer(n, nil)
+	C.git_note_free(n.ptr)
+	n.ptr = nil
+	return nil
+}
+
+// Author returns the signature of the note author
+func (n *Note) Author() *Signature {
+	ptr := C.git_note_author(n.ptr)
+	return newSignatureFromC(ptr)
+}
+
+// Id returns the note object's id
+func (n *Note) Id() *Oid {
+	ptr := C.git_note_id(n.ptr)
+	runtime.KeepAlive(n)
+	return newOidFromC(ptr)
+}
+
+// Committer returns the signature of the note committer
+func (n *Note) Committer() *Signature {
+	ptr := C.git_note_committer(n.ptr)
+	runtime.KeepAlive(n)
+	return newSignatureFromC(ptr)
+}
+
+// Message returns the note message
+func (n *Note) Message() string {
+	ret := C.GoString(C.git_note_message(n.ptr))
+	runtime.KeepAlive(n)
+	return ret
+}
+
+// NoteIterator
+type NoteIterator struct {
+	doNotCompare
+	ptr *C.git_note_iterator
+	r   *Repository
+}
+
+// NewNoteIterator creates a new iterator for notes
+func (repo *Repository) NewNoteIterator(ref string) (*NoteIterator, error) {
+	var cref *C.char
+	if ref == "" {
+		cref = nil
+	} else {
+		cref = C.CString(ref)
+		defer C.free(unsafe.Pointer(cref))
+	}
+
+	var ptr *C.git_note_iterator
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_note_iterator_new(&ptr, repo.ptr, cref)
+	runtime.KeepAlive(repo)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	iter := &NoteIterator{ptr: ptr, r: repo}
+	runtime.SetFinalizer(iter, (*NoteIterator).Free)
+	return iter, nil
+}
+
+// Free frees the note interator
+func (v *NoteIterator) Free() {
+	runtime.SetFinalizer(v, nil)
+	C.git_note_iterator_free(v.ptr)
+}
+
+// Next returns the current item (note id & annotated id) and advances the
+// iterator internally to the next item
+func (it *NoteIterator) Next() (noteId, annotatedId *Oid, err error) {
+	noteId, annotatedId = new(Oid), new(Oid)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_note_next(noteId.toC(), annotatedId.toC(), it.ptr)
+	runtime.KeepAlive(noteId)
+	runtime.KeepAlive(annotatedId)
+	runtime.KeepAlive(it)
+	if ret < 0 {
+		err = MakeGitError(ret)
+	}
+	return
+}

note_test.go

@@ -0,0 +1,117 @@
+package git
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+	"time"
+)
+
+func TestCreateNote(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitId)
+	checkFatal(t, err)
+
+	note, noteId := createTestNote(t, repo, commit)
+
+	compareStrings(t, "I am a note\n", note.Message())
+	compareStrings(t, noteId.String(), note.Id().String())
+	compareStrings(t, "alice", note.Author().Name)
+	compareStrings(t, "alice@example.com", note.Author().Email)
+	compareStrings(t, "alice", note.Committer().Name)
+	compareStrings(t, "alice@example.com", note.Committer().Email)
+}
+
+func TestNoteIterator(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	notes := make([]*Note, 5)
+	for i := range notes {
+		commitId, _ := updateReadme(t, repo, fmt.Sprintf("README v%d\n", i+1))
+		commit, err := repo.LookupCommit(commitId)
+		checkFatal(t, err)
+
+		note, _ := createTestNote(t, repo, commit)
+		notes[i] = note
+	}
+
+	iter, err := repo.NewNoteIterator("")
+	checkFatal(t, err)
+	for {
+		noteId, commitId, err := iter.Next()
+		if err != nil {
+			if !IsErrorCode(err, ErrorCodeIterOver) {
+				checkFatal(t, err)
+			}
+			break
+		}
+
+		note, err := repo.Notes.Read("", commitId)
+		checkFatal(t, err)
+
+		if !reflect.DeepEqual(note.Id(), noteId) {
+			t.Errorf("expected note oid '%v', actual '%v'", note.Id(), noteId)
+		}
+	}
+}
+
+func TestRemoveNote(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitId)
+	checkFatal(t, err)
+
+	note, _ := createTestNote(t, repo, commit)
+
+	_, err = repo.Notes.Read("", commit.Id())
+	checkFatal(t, err)
+
+	err = repo.Notes.Remove("", note.Author(), note.Committer(), commitId)
+	checkFatal(t, err)
+
+	_, err = repo.Notes.Read("", commit.Id())
+	if err == nil {
+		t.Fatal("note remove failed")
+	}
+}
+
+func TestDefaultNoteRef(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	ref, err := repo.Notes.DefaultRef()
+	checkFatal(t, err)
+
+	compareStrings(t, "refs/notes/commits", ref)
+}
+
+func createTestNote(t *testing.T, repo *Repository, commit *Commit) (*Note, *Oid) {
+	loc, err := time.LoadLocation("Europe/Berlin")
+	sig := &Signature{
+		Name:  "alice",
+		Email: "alice@example.com",
+		When:  time.Date(2015, 01, 05, 13, 0, 0, 0, loc),
+	}
+
+	noteId, err := repo.Notes.Create("", sig, sig, commit.Id(), "I am a note\n", false)
+	checkFatal(t, err)
+
+	note, err := repo.Notes.Read("", commit.Id())
+	checkFatal(t, err)
+
+	return note, noteId
+}

object.go

@@ -1,40 +1,43 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
 */
 import "C"
-import "runtime"
+import (
+	"errors"
+	"fmt"
+	"runtime"
+)
 
 type ObjectType int
 
 const (
-	ObjectAny ObjectType = C.GIT_OBJ_ANY
-	ObjectBad            = C.GIT_OBJ_BAD
-	ObjectCommit         = C.GIT_OBJ_COMMIT
-	ObjectTree           = C.GIT_OBJ_TREE
-	ObjectBlob           = C.GIT_OBJ_BLOB
-	ObjectTag            = C.GIT_OBJ_TAG
+	ObjectAny     ObjectType = C.GIT_OBJECT_ANY
+	ObjectInvalid ObjectType = C.GIT_OBJECT_INVALID
+	ObjectCommit  ObjectType = C.GIT_OBJECT_COMMIT
+	ObjectTree    ObjectType = C.GIT_OBJECT_TREE
+	ObjectBlob    ObjectType = C.GIT_OBJECT_BLOB
+	ObjectTag     ObjectType = C.GIT_OBJECT_TAG
 )
 
-type Object interface {
-	Free()
-	Id() *Oid
-	Type() ObjectType
+type Object struct {
+	doNotCompare
+	ptr  *C.git_object
+	repo *Repository
 }
 
-type gitObject struct {
-	ptr *C.git_object
+// Objecter lets us accept any kind of Git object in functions.
+type Objecter interface {
+	AsObject() *Object
 }
 
-func (t ObjectType) String() (string) {
-	switch (t) {
+func (t ObjectType) String() string {
+	switch t {
 	case ObjectAny:
 		return "Any"
-	case ObjectBad:
-		return "Bad"
+	case ObjectInvalid:
+		return "Invalid"
 	case ObjectCommit:
 		return "Commit"
 	case ObjectTree:
@@ -42,43 +45,194 @@ func (t ObjectType) String() (string) {
 	case ObjectBlob:
 		return "Blob"
 	case ObjectTag:
-		return "tag"
+		return "Tag"
 	}
 	// Never reached
 	return ""
 }
 
-func (o gitObject) Id() *Oid {
-	return newOidFromC(C.git_commit_id(o.ptr))
+func (o *Object) Id() *Oid {
+	ret := newOidFromC(C.git_object_id(o.ptr))
+	runtime.KeepAlive(o)
+	return ret
 }
 
-func (o gitObject) Type() ObjectType {
-	return ObjectType(C.git_object_type(o.ptr))
+func (o *Object) ShortId() (string, error) {
+	resultBuf := C.git_buf{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_object_short_id(&resultBuf, o.ptr)
+	runtime.KeepAlive(o)
+	if ecode < 0 {
+		return "", MakeGitError(ecode)
+	}
+	defer C.git_buf_dispose(&resultBuf)
+	return C.GoString(resultBuf.ptr), nil
 }
 
-func (o *gitObject) Free() {
-	runtime.SetFinalizer(o, nil)
-	C.git_commit_free(o.ptr)
+func (o *Object) Type() ObjectType {
+	ret := ObjectType(C.git_object_type(o.ptr))
+	runtime.KeepAlive(o)
+	return ret
 }
 
-func allocObject(cobj *C.git_object) Object {
+// Owner returns a weak reference to the repository which owns this object.
+// This won't keep the underlying repository alive, but it should still be
+// Freed.
+func (o *Object) Owner() *Repository {
+	repo := newRepositoryFromC(C.git_object_owner(o.ptr))
+	runtime.KeepAlive(o)
+	repo.weak = true
+	return repo
+}
 
-	switch ObjectType(C.git_object_type(cobj)) {
-	case ObjectCommit:
-		commit := &Commit{gitObject{cobj}}
-		runtime.SetFinalizer(commit, (*Commit).Free)
-		return commit
-
-	case ObjectTree:
-		tree := &Tree{gitObject{cobj}}
-		runtime.SetFinalizer(tree, (*Tree).Free)
-		return tree
-
-	case ObjectBlob:
-		blob := &Blob{gitObject{cobj}}
-		runtime.SetFinalizer(blob, (*Blob).Free)
-		return blob
+func dupObject(obj *Object, kind ObjectType) (*C.git_object, error) {
+	if obj.Type() != kind {
+		return nil, errors.New(fmt.Sprintf("object is not a %v", kind))
 	}
 
-	return nil
+	var cobj *C.git_object
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C.git_object_dup(&cobj, obj.ptr)
+	runtime.KeepAlive(obj)
+	if err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return cobj, nil
+}
+
+func allocTree(ptr *C.git_tree, repo *Repository) *Tree {
+	tree := &Tree{
+		Object: Object{
+			ptr:  (*C.git_object)(ptr),
+			repo: repo,
+		},
+		cast_ptr: ptr,
+	}
+	runtime.SetFinalizer(tree, (*Tree).Free)
+
+	return tree
+}
+
+func (o *Object) AsTree() (*Tree, error) {
+	cobj, err := dupObject(o, ObjectTree)
+	if err != nil {
+		return nil, err
+	}
+
+	return allocTree((*C.git_tree)(cobj), o.repo), nil
+}
+
+func allocCommit(ptr *C.git_commit, repo *Repository) *Commit {
+	commit := &Commit{
+		Object: Object{
+			ptr:  (*C.git_object)(ptr),
+			repo: repo,
+		},
+		cast_ptr: ptr,
+	}
+	runtime.SetFinalizer(commit, (*Commit).Free)
+
+	return commit
+}
+
+func (o *Object) AsCommit() (*Commit, error) {
+	cobj, err := dupObject(o, ObjectCommit)
+	if err != nil {
+		return nil, err
+	}
+
+	return allocCommit((*C.git_commit)(cobj), o.repo), nil
+}
+
+func allocBlob(ptr *C.git_blob, repo *Repository) *Blob {
+	blob := &Blob{
+		Object: Object{
+			ptr:  (*C.git_object)(ptr),
+			repo: repo,
+		},
+		cast_ptr: ptr,
+	}
+	runtime.SetFinalizer(blob, (*Blob).Free)
+
+	return blob
+}
+
+func (o *Object) AsBlob() (*Blob, error) {
+	cobj, err := dupObject(o, ObjectBlob)
+	if err != nil {
+		return nil, err
+	}
+
+	return allocBlob((*C.git_blob)(cobj), o.repo), nil
+}
+
+func allocTag(ptr *C.git_tag, repo *Repository) *Tag {
+	tag := &Tag{
+		Object: Object{
+			ptr:  (*C.git_object)(ptr),
+			repo: repo,
+		},
+		cast_ptr: ptr,
+	}
+	runtime.SetFinalizer(tag, (*Tag).Free)
+
+	return tag
+}
+
+func (o *Object) AsTag() (*Tag, error) {
+	cobj, err := dupObject(o, ObjectTag)
+	if err != nil {
+		return nil, err
+	}
+
+	return allocTag((*C.git_tag)(cobj), o.repo), nil
+}
+
+func (o *Object) Free() {
+	runtime.SetFinalizer(o, nil)
+	C.git_object_free(o.ptr)
+}
+
+// Peel recursively peels an object until an object of the specified type is met.
+//
+// If the query cannot be satisfied due to the object model, ErrorCodeInvalidSpec
+// will be returned (e.g. trying to peel a blob to a tree).
+//
+// If you pass ObjectAny as the target type, then the object will be peeled
+// until the type changes. A tag will be peeled until the referenced object
+// is no longer a tag, and a commit will be peeled to a tree. Any other object
+// type will return ErrorCodeInvalidSpec.
+//
+// If peeling a tag we discover an object which cannot be peeled to the target
+// type due to the object model, an error will be returned.
+func (o *Object) Peel(t ObjectType) (*Object, error) {
+	var cobj *C.git_object
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C.git_object_peel(&cobj, o.ptr, C.git_object_t(t))
+	runtime.KeepAlive(o)
+	if err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return allocObject(cobj, o.repo), nil
+}
+
+func allocObject(cobj *C.git_object, repo *Repository) *Object {
+	obj := &Object{
+		ptr:  cobj,
+		repo: repo,
+	}
+	runtime.SetFinalizer(obj, (*Object).Free)
+
+	return obj
 }

object_test.go

@@ -1,21 +1,23 @@
 package git
 
 import (
-	"os"
+	"strings"
 	"testing"
 )
 
 func TestObjectPoymorphism(t *testing.T) {
+	t.Parallel()
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
+
 	commitId, treeId := seedTestRepo(t, repo)
 
-	var obj Object
+	var obj *Object
 
 	commit, err := repo.LookupCommit(commitId)
 	checkFatal(t, err)
 
-	obj = commit
+	obj = &commit.Object
 	if obj.Type() != ObjectCommit {
 		t.Fatalf("Wrong object type, expected commit, have %v", obj.Type())
 	}
@@ -27,13 +29,13 @@ func TestObjectPoymorphism(t *testing.T) {
 	tree, err := repo.LookupTree(treeId)
 	checkFatal(t, err)
 
-	obj = tree
+	obj = &tree.Object
 	if obj.Type() != ObjectTree {
 		t.Fatalf("Wrong object type, expected tree, have %v", obj.Type())
 	}
 
-	tree2, ok := obj.(*Tree)
-	if !ok {
+	tree2, err := obj.AsTree()
+	if err != nil {
 		t.Fatalf("Converting back to *Tree is not ok")
 	}
 
@@ -46,16 +48,16 @@ func TestObjectPoymorphism(t *testing.T) {
 		t.Fatal("Wrong filemode for \"README\"")
 	}
 
-	_, ok = obj.(*Commit)
-	if ok {
+	_, err = obj.AsCommit()
+	if err == nil {
 		t.Fatalf("*Tree is somehow the same as *Commit")
 	}
 
 	obj, err = repo.Lookup(tree.Id())
 	checkFatal(t, err)
 
-	_, ok = obj.(*Tree)
-	if !ok {
+	_, err = obj.AsTree()
+	if err != nil {
 		t.Fatalf("Lookup creates the wrong type")
 	}
 
@@ -75,3 +77,118 @@ func TestObjectPoymorphism(t *testing.T) {
 		t.Fatalf("Failed to parse the right revision")
 	}
 }
+
+func checkOwner(t *testing.T, repo *Repository, obj Object) {
+	owner := obj.Owner()
+	if owner == nil {
+		t.Fatal("bad owner")
+	}
+
+	if owner.ptr != repo.ptr {
+		t.Fatalf("bad owner, got %v expected %v\n", owner.ptr, repo.ptr)
+	}
+}
+
+func TestObjectOwner(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId, treeId := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitId)
+	checkFatal(t, err)
+
+	tree, err := repo.LookupTree(treeId)
+	checkFatal(t, err)
+
+	checkOwner(t, repo, commit.Object)
+	checkOwner(t, repo, tree.Object)
+}
+
+func checkShortId(t *testing.T, Id, shortId string) {
+	if len(shortId) < 7 || len(shortId) >= len(Id) {
+		t.Fatalf("bad shortId length %d", len(shortId))
+	}
+
+	if !strings.HasPrefix(Id, shortId) {
+		t.Fatalf("bad shortId, should be prefix of %s, but is %s\n", Id, shortId)
+	}
+}
+
+func TestObjectShortId(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitId)
+	checkFatal(t, err)
+
+	shortId, err := commit.ShortId()
+	checkFatal(t, err)
+
+	checkShortId(t, commitId.String(), shortId)
+}
+
+func TestObjectPeel(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitID, treeID := seedTestRepo(t, repo)
+
+	var obj *Object
+
+	commit, err := repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	obj, err = commit.Peel(ObjectAny)
+	checkFatal(t, err)
+
+	if obj.Type() != ObjectTree {
+		t.Fatalf("Wrong object type when peeling a commit, expected tree, have %v", obj.Type())
+	}
+
+	obj, err = commit.Peel(ObjectTag)
+
+	if !IsErrorCode(err, ErrorCodeInvalidSpec) {
+		t.Fatalf("Wrong error when peeling a commit to a tag, expected ErrorCodeInvalidSpec, have %v", err)
+	}
+
+	tree, err := repo.LookupTree(treeID)
+	checkFatal(t, err)
+
+	obj, err = tree.Peel(ObjectAny)
+
+	if !IsErrorCode(err, ErrorCodeInvalidSpec) {
+		t.Fatalf("Wrong error when peeling a tree, expected ErrorCodeInvalidSpec, have %v", err)
+	}
+
+	entry := tree.EntryByName("README")
+
+	blob, err := repo.LookupBlob(entry.Id)
+	checkFatal(t, err)
+
+	obj, err = blob.Peel(ObjectAny)
+
+	if !IsErrorCode(err, ErrorCodeInvalidSpec) {
+		t.Fatalf("Wrong error when peeling a blob, expected ErrorCodeInvalidSpec, have %v", err)
+	}
+
+	tagID := createTestTag(t, repo, commit)
+
+	tag, err := repo.LookupTag(tagID)
+	checkFatal(t, err)
+
+	obj, err = tag.Peel(ObjectAny)
+	checkFatal(t, err)
+
+	if obj.Type() != ObjectCommit {
+		t.Fatalf("Wrong object type when peeling a tag, expected commit, have %v", obj.Type())
+	}
+
+	// TODO: Should test a tag that annotates a different object than a commit
+	// but it's impossible at the moment to tag such an object.
+}

odb.go

@@ -1,78 +1,347 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
 
+extern int git_odb_backend_one_pack(git_odb_backend **out, const char *index_file);
+extern int git_odb_backend_loose(git_odb_backend **out, const char *objects_dir, int compression_level, int do_fsync, unsigned int dir_mode, unsigned int file_mode);
 extern int _go_git_odb_foreach(git_odb *db, void *payload);
+extern void _go_git_odb_backend_free(git_odb_backend *backend);
+extern int _go_git_odb_write_pack(git_odb_writepack **out, git_odb *db, void *progress_payload);
+extern int _go_git_odb_writepack_append(git_odb_writepack *writepack, const void *, size_t, git_transfer_progress *);
+extern int _go_git_odb_writepack_commit(git_odb_writepack *writepack, git_transfer_progress *);
+extern void _go_git_odb_writepack_free(git_odb_writepack *writepack);
 */
 import "C"
 import (
-	"unsafe"
+	"io"
+	"os"
 	"reflect"
 	"runtime"
+	"unsafe"
 )
 
 type Odb struct {
+	doNotCompare
 	ptr *C.git_odb
 }
 
+type OdbBackend struct {
+	doNotCompare
+	ptr *C.git_odb_backend
+}
+
+func NewOdb() (odb *Odb, err error) {
+	odb = new(Odb)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_new(&odb.ptr)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	runtime.SetFinalizer(odb, (*Odb).Free)
+	return odb, nil
+}
+
+func NewOdbBackendFromC(ptr unsafe.Pointer) (backend *OdbBackend) {
+	backend = &OdbBackend{ptr: (*C.git_odb_backend)(ptr)}
+	return backend
+}
+
+func (v *Odb) AddAlternate(backend *OdbBackend, priority int) (err error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_add_alternate(v.ptr, backend.ptr, C.int(priority))
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		backend.Free()
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (v *Odb) AddBackend(backend *OdbBackend, priority int) (err error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_add_backend(v.ptr, backend.ptr, C.int(priority))
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		backend.Free()
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func NewOdbBackendOnePack(packfileIndexPath string) (backend *OdbBackend, err error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cstr := C.CString(packfileIndexPath)
+	defer C.free(unsafe.Pointer(cstr))
+
+	var odbOnePack *C.git_odb_backend = nil
+	ret := C.git_odb_backend_one_pack(&odbOnePack, cstr)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return NewOdbBackendFromC(unsafe.Pointer(odbOnePack)), nil
+}
+
+// NewOdbBackendLoose creates a backend for loose objects.
+func NewOdbBackendLoose(objectsDir string, compressionLevel int, doFsync bool, dirMode os.FileMode, fileMode os.FileMode) (backend *OdbBackend, err error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var odbLoose *C.git_odb_backend = nil
+	var doFsyncInt C.int
+	if doFsync {
+		doFsyncInt = C.int(1)
+	}
+
+	cstr := C.CString(objectsDir)
+	defer C.free(unsafe.Pointer(cstr))
+
+	ret := C.git_odb_backend_loose(&odbLoose, cstr, C.int(compressionLevel), doFsyncInt, C.uint(dirMode), C.uint(fileMode))
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return NewOdbBackendFromC(unsafe.Pointer(odbLoose)), nil
+}
+
+func (v *Odb) ReadHeader(oid *Oid) (uint64, ObjectType, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var sz C.size_t
+	var cotype C.git_object_t
+
+	ret := C.git_odb_read_header(&sz, &cotype, v.ptr, oid.toC())
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return 0, ObjectInvalid, MakeGitError(ret)
+	}
+
+	return uint64(sz), ObjectType(cotype), nil
+}
+
 func (v *Odb) Exists(oid *Oid) bool {
 	ret := C.git_odb_exists(v.ptr, oid.toC())
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(oid)
 	return ret != 0
 }
 
 func (v *Odb) Write(data []byte, otype ObjectType) (oid *Oid, err error) {
 	oid = new(Oid)
-	hdr := (*reflect.SliceHeader)(unsafe.Pointer(&data))
-	ret := C.git_odb_write(oid.toC(), v.ptr, unsafe.Pointer(hdr.Data), C.size_t(hdr.Len), C.git_otype(otype))
 
-	if ret < 0 {
-		err = LastError()
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var size C.size_t
+	if len(data) > 0 {
+		size = C.size_t(len(data))
+	} else {
+		data = []byte{0}
+		size = C.size_t(0)
 	}
 
-	return
+	ret := C.git_odb_write(oid.toC(), v.ptr, unsafe.Pointer(&data[0]), size, C.git_object_t(otype))
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return oid, nil
 }
 
 func (v *Odb) Read(oid *Oid) (obj *OdbObject, err error) {
 	obj = new(OdbObject)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_odb_read(&obj.ptr, v.ptr, oid.toC())
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(oid)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
 	runtime.SetFinalizer(obj, (*OdbObject).Free)
-	return
+	return obj, nil
 }
 
-//export odbForEachCb
-func odbForEachCb(id *C.git_oid, payload unsafe.Pointer) int {
-	ch := *(*chan *Oid)(payload)
-	oid := newOidFromC(id)
-	// Because the channel is unbuffered, we never read our own data. If ch is
-	// readable, the user has sent something on it, which means we should
-	// abort.
-	select {
-	case ch <- oid:
-	case <-ch:
-			return -1
+func (odb *Odb) Refresh() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_refresh(odb.ptr)
+	runtime.KeepAlive(odb)
+	if ret < 0 {
+		return MakeGitError(ret)
 	}
-	return 0;
+
+	return nil
 }
 
-func (v *Odb) forEachWrap(ch chan *Oid) {
-	C._go_git_odb_foreach(v.ptr, unsafe.Pointer(&ch))
-	close(ch)
+func (odb *Odb) WriteMultiPackIndex() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_write_multi_pack_index(odb.ptr)
+	runtime.KeepAlive(odb)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
 }
 
-func (v *Odb) ForEach() chan *Oid {
-	ch := make(chan *Oid, 0)
-	go v.forEachWrap(ch)
-	return ch
+type OdbForEachCallback func(id *Oid) error
+type odbForEachCallbackData struct {
+	callback    OdbForEachCallback
+	errorTarget *error
+}
+
+//export odbForEachCallback
+func odbForEachCallback(id *C.git_oid, handle unsafe.Pointer) C.int {
+	data, ok := pointerHandles.Get(handle).(*odbForEachCallbackData)
+	if !ok {
+		panic("could not retrieve handle")
+	}
+
+	err := data.callback(newOidFromC(id))
+	if err != nil {
+		*data.errorTarget = err
+		return C.int(ErrorCodeUser)
+	}
+
+	return C.int(ErrorCodeOK)
+}
+
+func (v *Odb) ForEach(callback OdbForEachCallback) error {
+	var err error
+	data := odbForEachCallbackData{
+		callback:    callback,
+		errorTarget: &err,
+	}
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	handle := pointerHandles.Track(&data)
+	defer pointerHandles.Untrack(handle)
+
+	ret := C._go_git_odb_foreach(v.ptr, handle)
+	runtime.KeepAlive(v)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+// Hash determines the object-ID (sha1) of a data buffer.
+func (v *Odb) Hash(data []byte, otype ObjectType) (oid *Oid, err error) {
+	oid = new(Oid)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var size C.size_t
+	if len(data) > 0 {
+		size = C.size_t(len(data))
+	} else {
+		data = []byte{0}
+		size = C.size_t(0)
+	}
+
+	ret := C.git_odb_hash(oid.toC(), unsafe.Pointer(&data[0]), size, C.git_object_t(otype))
+	runtime.KeepAlive(data)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return oid, nil
+}
+
+// NewReadStream opens a read stream from the ODB. Reading from it will give you the
+// contents of the object.
+func (v *Odb) NewReadStream(id *Oid) (*OdbReadStream, error) {
+	stream := new(OdbReadStream)
+	var ctype C.git_object_t
+	var csize C.size_t
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_open_rstream(&stream.ptr, &csize, &ctype, v.ptr, id.toC())
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(id)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	stream.Size = uint64(csize)
+	stream.Type = ObjectType(ctype)
+	runtime.SetFinalizer(stream, (*OdbReadStream).Free)
+	return stream, nil
+}
+
+// NewWriteStream opens a write stream to the ODB, which allows you to
+// create a new object in the database. The size and type must be
+// known in advance
+func (v *Odb) NewWriteStream(size int64, otype ObjectType) (*OdbWriteStream, error) {
+	stream := new(OdbWriteStream)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_open_wstream(&stream.ptr, v.ptr, C.git_object_size_t(size), C.git_object_t(otype))
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	runtime.SetFinalizer(stream, (*OdbWriteStream).Free)
+	return stream, nil
+}
+
+// NewWritePack opens a stream for writing a pack file to the ODB. If the ODB
+// layer understands pack files, then the given packfile will likely be
+// streamed directly to disk (and a corresponding index created). If the ODB
+// layer does not understand pack files, the objects will be stored in whatever
+// format the ODB layer uses.
+func (v *Odb) NewWritePack(callback TransferProgressCallback) (*OdbWritepack, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	writepack := new(OdbWritepack)
+	populateRemoteCallbacks(&writepack.ccallbacks, &RemoteCallbacks{TransferProgressCallback: callback}, nil)
+
+	ret := C._go_git_odb_write_pack(&writepack.ptr, v.ptr, writepack.ccallbacks.payload)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		untrackCallbacksPayload(&writepack.ccallbacks)
+		return nil, MakeGitError(ret)
+	}
+
+	runtime.SetFinalizer(writepack, (*OdbWritepack).Free)
+	return writepack, nil
+}
+
+func (v *OdbBackend) Free() {
+	C._go_git_odb_backend_free(v.ptr)
 }
 
 type OdbObject struct {
+	doNotCompare
 	ptr *C.git_odb_object
 }
 
@@ -82,13 +351,25 @@ func (v *OdbObject) Free() {
 }
 
 func (object *OdbObject) Id() (oid *Oid) {
-	return newOidFromC(C.git_odb_object_id(object.ptr))
+	ret := newOidFromC(C.git_odb_object_id(object.ptr))
+	runtime.KeepAlive(object)
+	return ret
 }
 
 func (object *OdbObject) Len() (len uint64) {
-	return uint64(C.git_odb_object_size(object.ptr))
+	ret := uint64(C.git_odb_object_size(object.ptr))
+	runtime.KeepAlive(object)
+	return ret
 }
 
+func (object *OdbObject) Type() ObjectType {
+	ret := ObjectType(C.git_odb_object_type(object.ptr))
+	runtime.KeepAlive(object)
+	return ret
+}
+
+// Data returns a slice pointing to the unmanaged object memory. You must make
+// sure the object is referenced for at least as long as the slice is used.
 func (object *OdbObject) Data() (data []byte) {
 	var c_blob unsafe.Pointer = C.git_odb_object_data(object.ptr)
 	var blob []byte
@@ -102,3 +383,132 @@ func (object *OdbObject) Data() (data []byte) {
 
 	return blob
 }
+
+type OdbReadStream struct {
+	doNotCompare
+	ptr  *C.git_odb_stream
+	Size uint64
+	Type ObjectType
+}
+
+// Read reads from the stream
+func (stream *OdbReadStream) Read(data []byte) (int, error) {
+	header := (*reflect.SliceHeader)(unsafe.Pointer(&data))
+	ptr := (*C.char)(unsafe.Pointer(header.Data))
+	size := C.size_t(header.Cap)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_stream_read(stream.ptr, ptr, size)
+	runtime.KeepAlive(stream)
+	if ret < 0 {
+		return 0, MakeGitError(ret)
+	}
+	if ret == 0 {
+		return 0, io.EOF
+	}
+
+	header.Len = int(ret)
+
+	return len(data), nil
+}
+
+// Close is a dummy function in order to implement the Closer and
+// ReadCloser interfaces
+func (stream *OdbReadStream) Close() error {
+	return nil
+}
+
+func (stream *OdbReadStream) Free() {
+	runtime.SetFinalizer(stream, nil)
+	C.git_odb_stream_free(stream.ptr)
+}
+
+type OdbWriteStream struct {
+	doNotCompare
+	ptr *C.git_odb_stream
+	Id  Oid
+}
+
+// Write writes to the stream
+func (stream *OdbWriteStream) Write(data []byte) (int, error) {
+	header := (*reflect.SliceHeader)(unsafe.Pointer(&data))
+	ptr := (*C.char)(unsafe.Pointer(header.Data))
+	size := C.size_t(header.Len)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_stream_write(stream.ptr, ptr, size)
+	runtime.KeepAlive(stream)
+	if ret < 0 {
+		return 0, MakeGitError(ret)
+	}
+
+	return len(data), nil
+}
+
+// Close signals that all the data has been written and stores the
+// resulting object id in the stream's Id field.
+func (stream *OdbWriteStream) Close() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_odb_stream_finalize_write(stream.Id.toC(), stream.ptr)
+	runtime.KeepAlive(stream)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (stream *OdbWriteStream) Free() {
+	runtime.SetFinalizer(stream, nil)
+	C.git_odb_stream_free(stream.ptr)
+}
+
+// OdbWritepack is a stream to write a packfile to the ODB.
+type OdbWritepack struct {
+	doNotCompare
+	ptr        *C.git_odb_writepack
+	stats      C.git_transfer_progress
+	ccallbacks C.git_remote_callbacks
+}
+
+func (writepack *OdbWritepack) Write(data []byte) (int, error) {
+	header := (*reflect.SliceHeader)(unsafe.Pointer(&data))
+	ptr := unsafe.Pointer(header.Data)
+	size := C.size_t(header.Len)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C._go_git_odb_writepack_append(writepack.ptr, ptr, size, &writepack.stats)
+	runtime.KeepAlive(writepack)
+	if ret < 0 {
+		return 0, MakeGitError(ret)
+	}
+
+	return len(data), nil
+}
+
+func (writepack *OdbWritepack) Commit() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C._go_git_odb_writepack_commit(writepack.ptr, &writepack.stats)
+	runtime.KeepAlive(writepack)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (writepack *OdbWritepack) Free() {
+	untrackCallbacksPayload(&writepack.ccallbacks)
+	runtime.SetFinalizer(writepack, nil)
+	C._go_git_odb_writepack_free(writepack.ptr)
+}

odb_test.go

@@ -0,0 +1,235 @@
+package git
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+	"testing"
+)
+
+func TestOdbRead(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, _ = seedTestRepo(t, repo)
+	odb, err := repo.Odb()
+	if err != nil {
+		t.Fatalf("Odb: %v", err)
+	}
+	data := []byte("hello")
+	id, err := odb.Write(data, ObjectBlob)
+	if err != nil {
+		t.Fatalf("odb.Write: %v", err)
+	}
+
+	sz, typ, err := odb.ReadHeader(id)
+	if err != nil {
+		t.Fatalf("ReadHeader: %v", err)
+	}
+
+	if sz != uint64(len(data)) {
+		t.Errorf("ReadHeader got size %d, want %d", sz, len(data))
+	}
+	if typ != ObjectBlob {
+		t.Errorf("ReadHeader got object type %s", typ)
+	}
+
+	obj, err := odb.Read(id)
+	if err != nil {
+		t.Fatalf("Read: %v", err)
+	}
+	if !bytes.Equal(obj.Data(), data) {
+		t.Errorf("Read got wrong data")
+	}
+	if sz := obj.Len(); sz != uint64(len(data)) {
+		t.Errorf("Read got size %d, want %d", sz, len(data))
+	}
+	if typ := obj.Type(); typ != ObjectBlob {
+		t.Errorf("Read got object type %s", typ)
+	}
+}
+
+func TestOdbStream(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, _ = seedTestRepo(t, repo)
+
+	odb, err := repo.Odb()
+	checkFatal(t, err)
+
+	str := "hello, world!"
+
+	writeStream, err := odb.NewWriteStream(int64(len(str)), ObjectBlob)
+	checkFatal(t, err)
+	n, err := io.WriteString(writeStream, str)
+	checkFatal(t, err)
+	if n != len(str) {
+		t.Fatalf("Bad write length %v != %v", n, len(str))
+	}
+
+	err = writeStream.Close()
+	checkFatal(t, err)
+
+	expectedId, err := NewOid("30f51a3fba5274d53522d0f19748456974647b4f")
+	checkFatal(t, err)
+	if writeStream.Id.Cmp(expectedId) != 0 {
+		t.Fatal("Wrong data written")
+	}
+
+	readStream, err := odb.NewReadStream(&writeStream.Id)
+	checkFatal(t, err)
+	data, err := ioutil.ReadAll(readStream)
+	if str != string(data) {
+		t.Fatalf("Wrong data read %v != %v", str, string(data))
+	}
+}
+
+func TestOdbHash(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, _ = seedTestRepo(t, repo)
+
+	odb, err := repo.Odb()
+	checkFatal(t, err)
+
+	str := `tree 115fcae49287c82eb55bb275cbbd4556fbed72b7
+parent 66e1c476199ebcd3e304659992233132c5a52c6c
+author John Doe <john@doe.com> 1390682018 +0000
+committer John Doe <john@doe.com> 1390682018 +0000
+
+Initial commit.`
+
+	for _, data := range [][]byte{[]byte(str), doublePointerBytes()} {
+		oid, err := odb.Hash(data, ObjectCommit)
+		checkFatal(t, err)
+
+		coid, err := odb.Write(data, ObjectCommit)
+		checkFatal(t, err)
+
+		if oid.Cmp(coid) != 0 {
+			t.Fatal("Hash and write Oids are different")
+		}
+	}
+}
+
+func TestOdbForeach(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, _ = seedTestRepo(t, repo)
+
+	odb, err := repo.Odb()
+	checkFatal(t, err)
+
+	expect := 3
+	count := 0
+	err = odb.ForEach(func(id *Oid) error {
+		count++
+		return nil
+	})
+
+	checkFatal(t, err)
+	if count != expect {
+		t.Fatalf("Expected %v objects, got %v", expect, count)
+	}
+
+	expect = 1
+	count = 0
+	to_return := errors.New("not really an error")
+	err = odb.ForEach(func(id *Oid) error {
+		count++
+		return to_return
+	})
+
+	if err != to_return {
+		t.Fatalf("Odb.ForEach() did not return the expected error, got %v", err)
+	}
+}
+
+func TestOdbWritepack(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, _ = seedTestRepo(t, repo)
+
+	odb, err := repo.Odb()
+	checkFatal(t, err)
+
+	var finalStats TransferProgress
+	writepack, err := odb.NewWritePack(func(stats TransferProgress) error {
+		finalStats = stats
+		return nil
+	})
+	checkFatal(t, err)
+	defer writepack.Free()
+
+	_, err = writepack.Write(outOfOrderPack)
+	checkFatal(t, err)
+	err = writepack.Commit()
+	checkFatal(t, err)
+
+	if finalStats.TotalObjects != 3 {
+		t.Errorf("mismatched transferred objects, expected 3, got %v", finalStats.TotalObjects)
+	}
+	if finalStats.ReceivedObjects != 3 {
+		t.Errorf("mismatched received objects, expected 3, got %v", finalStats.ReceivedObjects)
+	}
+	if finalStats.IndexedObjects != 3 {
+		t.Errorf("mismatched indexed objects, expected 3, got %v", finalStats.IndexedObjects)
+	}
+}
+
+func TestOdbBackendLoose(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, _ = seedTestRepo(t, repo)
+
+	odb, err := repo.Odb()
+	checkFatal(t, err)
+
+	looseObjectsDir, err := ioutil.TempDir("", fmt.Sprintf("loose_objects_%s", path.Base(repo.Path())))
+	checkFatal(t, err)
+	defer os.RemoveAll(looseObjectsDir)
+
+	looseObjectsBackend, err := NewOdbBackendLoose(looseObjectsDir, -1, false, 0, 0)
+	checkFatal(t, err)
+	if err := odb.AddBackend(looseObjectsBackend, 999); err != nil {
+		looseObjectsBackend.Free()
+		checkFatal(t, err)
+	}
+
+	str := "hello, world!"
+
+	writeStream, err := odb.NewWriteStream(int64(len(str)), ObjectBlob)
+	checkFatal(t, err)
+	n, err := io.WriteString(writeStream, str)
+	checkFatal(t, err)
+	if n != len(str) {
+		t.Fatalf("Bad write length %v != %v", n, len(str))
+	}
+
+	err = writeStream.Close()
+	checkFatal(t, err)
+
+	expectedId, err := NewOid("30f51a3fba5274d53522d0f19748456974647b4f")
+	checkFatal(t, err)
+	if !writeStream.Id.Equal(expectedId) {
+		t.Fatalf("writeStream.id = %v; want %v", writeStream.Id, expectedId)
+	}
+
+	_, err = os.Stat(path.Join(looseObjectsDir, expectedId.String()[:2], expectedId.String()[2:]))
+	checkFatal(t, err)
+}

packbuilder.go

@@ -1,9 +1,7 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
 #include <git2/pack.h>
 #include <stdlib.h>
 
@@ -12,22 +10,33 @@ extern int _go_git_packbuilder_foreach(git_packbuilder *pb, void *payload);
 import "C"
 import (
 	"io"
+	"os"
 	"runtime"
 	"unsafe"
 )
 
 type Packbuilder struct {
+	doNotCompare
 	ptr *C.git_packbuilder
+	r   *Repository
 }
 
 func (repo *Repository) NewPackbuilder() (*Packbuilder, error) {
-	builder := &Packbuilder{}
-	ret := C.git_packbuilder_new(&builder.ptr, repo.ptr)
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_packbuilder
+	ret := C.git_packbuilder_new(&ptr, repo.ptr)
 	if ret != 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
-	runtime.SetFinalizer(builder, (*Packbuilder).Free)
-	return builder, nil
+	return newPackbuilderFromC(ptr, repo), nil
+}
+
+func newPackbuilderFromC(ptr *C.git_packbuilder, r *Repository) *Packbuilder {
+	pb := &Packbuilder{ptr: ptr, r: r}
+	runtime.SetFinalizer(pb, (*Packbuilder).Free)
+	return pb
 }
 
 func (pb *Packbuilder) Free() {
@@ -38,93 +47,139 @@ func (pb *Packbuilder) Free() {
 func (pb *Packbuilder) Insert(id *Oid, name string) error {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_packbuilder_insert(pb.ptr, id.toC(), cname)
+	runtime.KeepAlive(pb)
+	runtime.KeepAlive(id)
 	if ret != 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 	return nil
 }
 
 func (pb *Packbuilder) InsertCommit(id *Oid) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_packbuilder_insert_commit(pb.ptr, id.toC())
+	runtime.KeepAlive(pb)
+	runtime.KeepAlive(id)
 	if ret != 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 	return nil
 }
 
 func (pb *Packbuilder) InsertTree(id *Oid) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_packbuilder_insert_tree(pb.ptr, id.toC())
+	runtime.KeepAlive(pb)
+	runtime.KeepAlive(id)
 	if ret != 0 {
-		return LastError()
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (pb *Packbuilder) InsertWalk(walk *RevWalk) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_packbuilder_insert_walk(pb.ptr, walk.ptr)
+	runtime.KeepAlive(pb)
+	runtime.KeepAlive(walk)
+	if ret != 0 {
+		return MakeGitError(ret)
 	}
 	return nil
 }
 
 func (pb *Packbuilder) ObjectCount() uint32 {
-	return uint32(C.git_packbuilder_object_count(pb.ptr))
+	ret := uint32(C.git_packbuilder_object_count(pb.ptr))
+	runtime.KeepAlive(pb)
+	return ret
 }
 
-func (pb *Packbuilder) WriteToFile(name string) error {
+func (pb *Packbuilder) WriteToFile(name string, mode os.FileMode) error {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
-	ret := C.git_packbuilder_write(pb.ptr, cname, nil, nil)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_packbuilder_write(pb.ptr, cname, C.uint(mode.Perm()), nil, nil)
+	runtime.KeepAlive(pb)
 	if ret != 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 	return nil
 }
 
 func (pb *Packbuilder) Write(w io.Writer) error {
-	ch, stop := pb.ForEach()
-	for slice := range ch {
+	return pb.ForEach(func(slice []byte) error {
 		_, err := w.Write(slice)
-		if err != nil {
-			close(stop)
-			return err
-		}
-	}
-	return nil
+		return err
+	})
 }
 
 func (pb *Packbuilder) Written() uint32 {
-	return uint32(C.git_packbuilder_written(pb.ptr))
+	ret := uint32(C.git_packbuilder_written(pb.ptr))
+	runtime.KeepAlive(pb)
+	return ret
 }
 
-type packbuilderCbData struct {
-	ch chan<- []byte
-	stop <-chan bool
+type PackbuilderForeachCallback func([]byte) error
+type packbuilderCallbackData struct {
+	callback    PackbuilderForeachCallback
+	errorTarget *error
 }
 
-//export packbuilderForEachCb
-func packbuilderForEachCb(buf unsafe.Pointer, size C.size_t, payload unsafe.Pointer) int {
-	data := (*packbuilderCbData)(payload)
-	ch := data.ch
-	stop := data.stop
-
-	slice := C.GoBytes(buf, C.int(size))
-	select {
-	case <- stop:
-		return -1
-	case ch <- slice:
+//export packbuilderForEachCallback
+func packbuilderForEachCallback(buf unsafe.Pointer, size C.size_t, handle unsafe.Pointer) C.int {
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*packbuilderCallbackData)
+	if !ok {
+		panic("could not get packbuilder CB data")
 	}
 
-	return 0
+	slice := C.GoBytes(buf, C.int(size))
+
+	err := data.callback(slice)
+	if err != nil {
+		*data.errorTarget = err
+		return C.int(ErrorCodeUser)
+	}
+
+	return C.int(ErrorCodeOK)
 }
 
-func (pb *Packbuilder) forEachWrap(data *packbuilderCbData) {
-	C._go_git_packbuilder_foreach(pb.ptr, unsafe.Pointer(data))
-	close(data.ch)
-}
+// ForEach repeatedly calls the callback with new packfile data until
+// there is no more data or the callback returns an error
+func (pb *Packbuilder) ForEach(callback PackbuilderForeachCallback) error {
+	var err error
+	data := packbuilderCallbackData{
+		callback:    callback,
+		errorTarget: &err,
+	}
+	handle := pointerHandles.Track(&data)
+	defer pointerHandles.Untrack(handle)
 
-// Foreach sends the packfile as slices through the "data" channel. If
-// you want to stop the pack-building process (e.g. there's an error
-// writing to the output), close or write a value into the "stop"
-// channel.
-func (pb *Packbuilder) ForEach() (<-chan []byte, chan<- bool) {
-	ch := make(chan []byte)
-	stop := make(chan bool)
-	data := packbuilderCbData{ch, stop}
-	go pb.forEachWrap(&data)
-	return ch, stop
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C._go_git_packbuilder_foreach(pb.ptr, handle)
+	runtime.KeepAlive(pb)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
 }

patch.go

@@ -0,0 +1,99 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+type Patch struct {
+	doNotCompare
+	ptr *C.git_patch
+}
+
+func newPatchFromC(ptr *C.git_patch) *Patch {
+	if ptr == nil {
+		return nil
+	}
+
+	patch := &Patch{
+		ptr: ptr,
+	}
+
+	runtime.SetFinalizer(patch, (*Patch).Free)
+	return patch
+}
+
+func (patch *Patch) Free() error {
+	if patch.ptr == nil {
+		return ErrInvalid
+	}
+	runtime.SetFinalizer(patch, nil)
+	C.git_patch_free(patch.ptr)
+	patch.ptr = nil
+	return nil
+}
+
+func (patch *Patch) String() (string, error) {
+	if patch.ptr == nil {
+		return "", ErrInvalid
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var buf C.git_buf
+
+	ecode := C.git_patch_to_buf(&buf, patch.ptr)
+	runtime.KeepAlive(patch)
+	if ecode < 0 {
+		return "", MakeGitError(ecode)
+	}
+	defer C.git_buf_dispose(&buf)
+
+	return C.GoString(buf.ptr), nil
+}
+
+func toPointer(data []byte) (ptr unsafe.Pointer) {
+	if len(data) > 0 {
+		ptr = unsafe.Pointer(&data[0])
+	} else {
+		ptr = unsafe.Pointer(nil)
+	}
+	return
+}
+
+func (v *Repository) PatchFromBuffers(oldPath, newPath string, oldBuf, newBuf []byte, opts *DiffOptions) (*Patch, error) {
+	var patchPtr *C.git_patch
+
+	oldPtr := toPointer(oldBuf)
+	newPtr := toPointer(newBuf)
+
+	cOldPath := C.CString(oldPath)
+	defer C.free(unsafe.Pointer(cOldPath))
+
+	cNewPath := C.CString(newPath)
+	defer C.free(unsafe.Pointer(cNewPath))
+
+	var err error
+	copts := populateDiffOptions(&C.git_diff_options{}, opts, v, &err)
+	defer freeDiffOptions(copts)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_patch_from_buffers(&patchPtr, oldPtr, C.size_t(len(oldBuf)), cOldPath, newPtr, C.size_t(len(newBuf)), cNewPath, copts)
+	runtime.KeepAlive(oldBuf)
+	runtime.KeepAlive(newBuf)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return nil, err
+	}
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newPatchFromC(patchPtr), nil
+}

patch_test.go

@@ -0,0 +1,38 @@
+package git
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestPatch(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, originalTreeId := seedTestRepo(t, repo)
+	originalTree, err := repo.LookupTree(originalTreeId)
+
+	checkFatal(t, err)
+
+	_, newTreeId := updateReadme(t, repo, "file changed\n")
+
+	newTree, err := repo.LookupTree(newTreeId)
+	checkFatal(t, err)
+
+	opts := &DiffOptions{
+		OldPrefix: "a",
+		NewPrefix: "b",
+	}
+	diff, err := repo.DiffTreeToTree(originalTree, newTree, opts)
+	checkFatal(t, err)
+
+	patch, err := diff.Patch(0)
+	checkFatal(t, err)
+
+	patchStr, err := patch.String()
+	checkFatal(t, err)
+	if strings.Index(patchStr, "diff --git a/README b/README\nindex 257cc56..820734a 100644\n--- a/README\n+++ b/README\n@@ -1 +1 @@\n-foo\n+file changed") == -1 {
+		t.Fatalf("patch was bad")
+	}
+}

push_test.go

@@ -0,0 +1,31 @@
+package git
+
+import (
+	"testing"
+)
+
+func TestRemotePush(t *testing.T) {
+	t.Parallel()
+	repo := createBareTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	localRepo := createTestRepo(t)
+	defer cleanupTestRepo(t, localRepo)
+
+	remote, err := localRepo.Remotes.Create("test_push", repo.Path())
+	checkFatal(t, err)
+	defer remote.Free()
+
+	seedTestRepo(t, localRepo)
+
+	err = remote.Push([]string{"refs/heads/master"}, nil)
+	checkFatal(t, err)
+
+	ref, err := localRepo.References.Lookup("refs/remotes/test_push/master")
+	checkFatal(t, err)
+	defer ref.Free()
+
+	ref, err = repo.References.Lookup("refs/heads/master")
+	checkFatal(t, err)
+	defer ref.Free()
+}

rebase.go

@@ -0,0 +1,485 @@
+package git
+
+/*
+#include <git2.h>
+
+extern void _go_git_populate_rebase_callbacks(git_rebase_options *opts);
+*/
+import "C"
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"runtime"
+	"unsafe"
+)
+
+// RebaseOperationType is the type of rebase operation
+type RebaseOperationType uint
+
+const (
+	// RebaseOperationPick The given commit is to be cherry-picked.  The client should commit the changes and continue if there are no conflicts.
+	RebaseOperationPick RebaseOperationType = C.GIT_REBASE_OPERATION_PICK
+	// RebaseOperationReword The given commit is to be cherry-picked, but the client should prompt the user to provide an updated commit message.
+	RebaseOperationReword RebaseOperationType = C.GIT_REBASE_OPERATION_REWORD
+	// RebaseOperationEdit The given commit is to be cherry-picked, but the client should stop to allow the user to edit the changes before committing them.
+	RebaseOperationEdit RebaseOperationType = C.GIT_REBASE_OPERATION_EDIT
+	// RebaseOperationSquash The given commit is to be squashed into the previous commit.  The commit message will be merged with the previous message.
+	RebaseOperationSquash RebaseOperationType = C.GIT_REBASE_OPERATION_SQUASH
+	// RebaseOperationFixup No commit will be cherry-picked.  The client should run the given command and (if successful) continue.
+	RebaseOperationFixup RebaseOperationType = C.GIT_REBASE_OPERATION_FIXUP
+	// RebaseOperationExec No commit will be cherry-picked.  The client should run the given command and (if successful) continue.
+	RebaseOperationExec RebaseOperationType = C.GIT_REBASE_OPERATION_EXEC
+)
+
+func (t RebaseOperationType) String() string {
+	switch t {
+	case RebaseOperationPick:
+		return "pick"
+	case RebaseOperationReword:
+		return "reword"
+	case RebaseOperationEdit:
+		return "edit"
+	case RebaseOperationSquash:
+		return "squash"
+	case RebaseOperationFixup:
+		return "fixup"
+	case RebaseOperationExec:
+		return "exec"
+	}
+	return fmt.Sprintf("RebaseOperationType(%d)", t)
+}
+
+// Special value indicating that there is no currently active operation
+var RebaseNoOperation uint = ^uint(0)
+
+// Error returned if there is no current rebase operation
+var ErrRebaseNoOperation = errors.New("no current rebase operation")
+
+// RebaseOperation describes a single instruction/operation to be performed during the rebase.
+type RebaseOperation struct {
+	Type RebaseOperationType
+	Id   *Oid
+	Exec string
+}
+
+func newRebaseOperationFromC(c *C.git_rebase_operation) *RebaseOperation {
+	operation := &RebaseOperation{}
+	operation.Type = RebaseOperationType(c._type)
+	operation.Id = newOidFromC(&c.id)
+	operation.Exec = C.GoString(c.exec)
+
+	return operation
+}
+
+//export commitCreateCallback
+func commitCreateCallback(
+	errorMessage **C.char,
+	_out *C.git_oid,
+	_author, _committer *C.git_signature,
+	_message_encoding, _message *C.char,
+	_tree *C.git_tree,
+	_parent_count C.size_t,
+	_parents **C.git_commit,
+	handle unsafe.Pointer,
+) C.int {
+	data, ok := pointerHandles.Get(handle).(*rebaseOptionsData)
+	if !ok {
+		panic("invalid sign payload")
+	}
+
+	if data.options.CommitCreateCallback == nil && data.options.CommitSigningCallback == nil {
+		return C.int(ErrorCodePassthrough)
+	}
+
+	messageEncoding := MessageEncodingUTF8
+	if _message_encoding != nil {
+		messageEncoding = MessageEncoding(C.GoString(_message_encoding))
+	}
+	tree := &Tree{
+		Object: Object{
+			ptr:  (*C.git_object)(_tree),
+			repo: data.repo,
+		},
+		cast_ptr: _tree,
+	}
+
+	var goParents []*C.git_commit
+	if _parent_count > 0 {
+		hdr := reflect.SliceHeader{
+			Data: uintptr(unsafe.Pointer(_parents)),
+			Len:  int(_parent_count),
+			Cap:  int(_parent_count),
+		}
+		goParents = *(*[]*C.git_commit)(unsafe.Pointer(&hdr))
+	}
+
+	parents := make([]*Commit, int(_parent_count))
+	for i, p := range goParents {
+		parents[i] = &Commit{
+			Object: Object{
+				ptr:  (*C.git_object)(p),
+				repo: data.repo,
+			},
+			cast_ptr: p,
+		}
+	}
+
+	if data.options.CommitCreateCallback != nil {
+		oid, err := data.options.CommitCreateCallback(
+			newSignatureFromC(_author),
+			newSignatureFromC(_committer),
+			messageEncoding,
+			C.GoString(_message),
+			tree,
+			parents...,
+		)
+		if err != nil {
+			if data.errorTarget != nil {
+				*data.errorTarget = err
+			}
+			return setCallbackError(errorMessage, err)
+		}
+		if oid == nil {
+			return C.int(ErrorCodePassthrough)
+		}
+		*_out = *oid.toC()
+	} else if data.options.CommitSigningCallback != nil {
+		commitContent, err := data.repo.CreateCommitBuffer(
+			newSignatureFromC(_author),
+			newSignatureFromC(_committer),
+			messageEncoding,
+			C.GoString(_message),
+			tree,
+			parents...,
+		)
+		if err != nil {
+			if data.errorTarget != nil {
+				*data.errorTarget = err
+			}
+			return setCallbackError(errorMessage, err)
+		}
+
+		signature, signatureField, err := data.options.CommitSigningCallback(string(commitContent))
+		if err != nil {
+			if data.errorTarget != nil {
+				*data.errorTarget = err
+			}
+			return setCallbackError(errorMessage, err)
+		}
+
+		oid, err := data.repo.CreateCommitWithSignature(string(commitContent), signature, signatureField)
+		if err != nil {
+			if data.errorTarget != nil {
+				*data.errorTarget = err
+			}
+			return setCallbackError(errorMessage, err)
+		}
+		*_out = *oid.toC()
+	}
+
+	return C.int(ErrorCodeOK)
+}
+
+// RebaseOptions are used to tell the rebase machinery how to operate.
+type RebaseOptions struct {
+	Quiet           int
+	InMemory        int
+	RewriteNotesRef string
+	MergeOptions    MergeOptions
+	CheckoutOptions CheckoutOptions
+	// CommitCreateCallback is an optional callback that allows users to override
+	// commit creation when rebasing. If specified, users can create
+	// their own commit and provide the commit ID, which may be useful for
+	// signing commits or otherwise customizing the commit creation. If this
+	// callback returns a nil Oid, then the rebase will continue to create the
+	// commit.
+	CommitCreateCallback CommitCreateCallback
+	// Deprecated: CommitSigningCallback is an optional callback that will be
+	// called with the commit content, allowing a signature to be added to the
+	// rebase commit. This field is only used when rebasing.  This callback is
+	// not invoked if a CommitCreateCallback is specified.  CommitCreateCallback
+	// should be used instead of this.
+	CommitSigningCallback CommitSigningCallback
+}
+
+type rebaseOptionsData struct {
+	options     *RebaseOptions
+	repo        *Repository
+	errorTarget *error
+}
+
+// DefaultRebaseOptions returns a RebaseOptions with default values.
+func DefaultRebaseOptions() (RebaseOptions, error) {
+	opts := C.git_rebase_options{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_rebase_options_init(&opts, C.GIT_REBASE_OPTIONS_VERSION)
+	if ecode < 0 {
+		return RebaseOptions{}, MakeGitError(ecode)
+	}
+	return rebaseOptionsFromC(&opts), nil
+}
+
+func rebaseOptionsFromC(opts *C.git_rebase_options) RebaseOptions {
+	return RebaseOptions{
+		Quiet:           int(opts.quiet),
+		InMemory:        int(opts.inmemory),
+		RewriteNotesRef: C.GoString(opts.rewrite_notes_ref),
+		MergeOptions:    mergeOptionsFromC(&opts.merge_options),
+		CheckoutOptions: checkoutOptionsFromC(&opts.checkout_options),
+	}
+}
+
+func populateRebaseOptions(copts *C.git_rebase_options, opts *RebaseOptions, repo *Repository, errorTarget *error) *C.git_rebase_options {
+	C.git_rebase_options_init(copts, C.GIT_REBASE_OPTIONS_VERSION)
+	if opts == nil {
+		return nil
+	}
+
+	copts.quiet = C.int(opts.Quiet)
+	copts.inmemory = C.int(opts.InMemory)
+	copts.rewrite_notes_ref = mapEmptyStringToNull(opts.RewriteNotesRef)
+	populateMergeOptions(&copts.merge_options, &opts.MergeOptions)
+	populateCheckoutOptions(&copts.checkout_options, &opts.CheckoutOptions, errorTarget)
+
+	if opts.CommitCreateCallback != nil || opts.CommitSigningCallback != nil {
+		data := &rebaseOptionsData{
+			options:     opts,
+			repo:        repo,
+			errorTarget: errorTarget,
+		}
+		C._go_git_populate_rebase_callbacks(copts)
+		copts.payload = pointerHandles.Track(data)
+	}
+
+	return copts
+}
+
+func freeRebaseOptions(copts *C.git_rebase_options) {
+	if copts == nil {
+		return
+	}
+	C.free(unsafe.Pointer(copts.rewrite_notes_ref))
+	freeMergeOptions(&copts.merge_options)
+	freeCheckoutOptions(&copts.checkout_options)
+	if copts.payload != nil {
+		pointerHandles.Untrack(copts.payload)
+	}
+}
+
+func mapEmptyStringToNull(ref string) *C.char {
+	if ref == "" {
+		return nil
+	}
+	return C.CString(ref)
+}
+
+// Rebase is the struct representing a Rebase object.
+type Rebase struct {
+	doNotCompare
+	ptr     *C.git_rebase
+	r       *Repository
+	options *C.git_rebase_options
+}
+
+// InitRebase initializes a rebase operation to rebase the changes in branch relative to upstream onto another branch.
+func (r *Repository) InitRebase(branch *AnnotatedCommit, upstream *AnnotatedCommit, onto *AnnotatedCommit, opts *RebaseOptions) (*Rebase, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if branch == nil {
+		branch = &AnnotatedCommit{ptr: nil}
+	}
+
+	if upstream == nil {
+		upstream = &AnnotatedCommit{ptr: nil}
+	}
+
+	if onto == nil {
+		onto = &AnnotatedCommit{ptr: nil}
+	}
+
+	var ptr *C.git_rebase
+	var err error
+	cOpts := populateRebaseOptions(&C.git_rebase_options{}, opts, r, &err)
+	ret := C.git_rebase_init(&ptr, r.ptr, branch.ptr, upstream.ptr, onto.ptr, cOpts)
+	runtime.KeepAlive(branch)
+	runtime.KeepAlive(upstream)
+	runtime.KeepAlive(onto)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		freeRebaseOptions(cOpts)
+		return nil, err
+	}
+	if ret < 0 {
+		freeRebaseOptions(cOpts)
+		return nil, MakeGitError(ret)
+	}
+
+	return newRebaseFromC(ptr, r, cOpts), nil
+}
+
+// OpenRebase opens an existing rebase that was previously started by either an invocation of InitRebase or by another client.
+func (r *Repository) OpenRebase(opts *RebaseOptions) (*Rebase, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_rebase
+	var err error
+	cOpts := populateRebaseOptions(&C.git_rebase_options{}, opts, r, &err)
+	ret := C.git_rebase_open(&ptr, r.ptr, cOpts)
+	runtime.KeepAlive(r)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		freeRebaseOptions(cOpts)
+		return nil, err
+	}
+	if ret < 0 {
+		freeRebaseOptions(cOpts)
+		return nil, MakeGitError(ret)
+	}
+
+	return newRebaseFromC(ptr, r, cOpts), nil
+}
+
+// OperationAt gets the rebase operation specified by the given index.
+func (rebase *Rebase) OperationAt(index uint) *RebaseOperation {
+	operation := C.git_rebase_operation_byindex(rebase.ptr, C.size_t(index))
+
+	return newRebaseOperationFromC(operation)
+}
+
+// CurrentOperationIndex gets the index of the rebase operation that is
+// currently being applied. There is also an error returned for API
+// compatibility.
+func (rebase *Rebase) CurrentOperationIndex() (uint, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var err error
+	operationIndex := uint(C.git_rebase_operation_current(rebase.ptr))
+	runtime.KeepAlive(rebase)
+	if operationIndex == RebaseNoOperation {
+		err = ErrRebaseNoOperation
+	}
+
+	return uint(operationIndex), err
+}
+
+// OperationCount gets the count of rebase operations that are to be applied.
+func (rebase *Rebase) OperationCount() uint {
+	ret := uint(C.git_rebase_operation_entrycount(rebase.ptr))
+	runtime.KeepAlive(rebase)
+	return ret
+}
+
+// Next performs the next rebase operation and returns the information about it.
+// If the operation is one that applies a patch (which is any operation except RebaseOperationExec)
+// then the patch will be applied and the index and working directory will be updated with the changes.
+// If there are conflicts, you will need to address those before committing the changes.
+func (rebase *Rebase) Next() (*RebaseOperation, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_rebase_operation
+	err := C.git_rebase_next(&ptr, rebase.ptr)
+	runtime.KeepAlive(rebase)
+	if err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return newRebaseOperationFromC(ptr), nil
+}
+
+// InmemoryIndex gets the index produced by the last operation, which is the
+// result of `Next()` and which will be committed by the next invocation of
+// `Commit()`. This is useful for resolving conflicts in an in-memory rebase
+// before committing them.
+//
+// This is only applicable for in-memory rebases; for rebases within a working
+// directory, the changes were applied to the repository's index.
+func (rebase *Rebase) InmemoryIndex() (*Index, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_index
+	err := C.git_rebase_inmemory_index(&ptr, rebase.ptr)
+	runtime.KeepAlive(rebase)
+	if err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return newIndexFromC(ptr, rebase.r), nil
+}
+
+// Commit commits the current patch.
+// You must have resolved any conflicts that were introduced during the patch application from the Next() invocation.
+func (rebase *Rebase) Commit(ID *Oid, author, committer *Signature, message string) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	authorSig, err := author.toC()
+	if err != nil {
+		return err
+	}
+	defer C.git_signature_free(authorSig)
+
+	committerSig, err := committer.toC()
+	if err != nil {
+		return err
+	}
+	defer C.git_signature_free(committerSig)
+
+	cmsg := C.CString(message)
+	defer C.free(unsafe.Pointer(cmsg))
+
+	cerr := C.git_rebase_commit(ID.toC(), rebase.ptr, authorSig, committerSig, nil, cmsg)
+	runtime.KeepAlive(ID)
+	runtime.KeepAlive(rebase)
+	if cerr < 0 {
+		return MakeGitError(cerr)
+	}
+
+	return nil
+}
+
+// Finish finishes a rebase that is currently in progress once all patches have been applied.
+func (rebase *Rebase) Finish() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C.git_rebase_finish(rebase.ptr, nil)
+	runtime.KeepAlive(rebase)
+	if err < 0 {
+		return MakeGitError(err)
+	}
+
+	return nil
+}
+
+// Abort aborts a rebase that is currently in progress, resetting the repository and working directory to their state before rebase began.
+func (rebase *Rebase) Abort() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C.git_rebase_abort(rebase.ptr)
+	runtime.KeepAlive(rebase)
+	if err < 0 {
+		return MakeGitError(err)
+	}
+	return nil
+}
+
+// Free frees the Rebase object.
+func (r *Rebase) Free() {
+	runtime.SetFinalizer(r, nil)
+	C.git_rebase_free(r.ptr)
+	freeRebaseOptions(r.options)
+}
+
+func newRebaseFromC(ptr *C.git_rebase, repo *Repository, opts *C.git_rebase_options) *Rebase {
+	rebase := &Rebase{ptr: ptr, r: repo, options: opts}
+	runtime.SetFinalizer(rebase, (*Rebase).Free)
+	return rebase
+}

rebase_test.go

@@ -0,0 +1,602 @@
+package git
+
+import (
+	"bytes"
+	"errors"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/ProtonMail/go-crypto/openpgp"
+	"github.com/ProtonMail/go-crypto/openpgp/packet"
+)
+
+// Tests
+
+func TestRebaseInMemoryWithConflict(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+	seedTestRepo(t, repo)
+
+	// Create two branches with common history, where both modify "common-file"
+	// in a conflicting way.
+	_, err := commitSomething(repo, "common-file", "a\nb\nc\n", commitOptions{})
+	checkFatal(t, err)
+	checkFatal(t, createBranch(repo, "branch-a"))
+	checkFatal(t, createBranch(repo, "branch-b"))
+
+	checkFatal(t, repo.SetHead("refs/heads/branch-a"))
+	_, err = commitSomething(repo, "common-file", "1\nb\nc\n", commitOptions{})
+	checkFatal(t, err)
+
+	checkFatal(t, repo.SetHead("refs/heads/branch-b"))
+	_, err = commitSomething(repo, "common-file", "x\nb\nc\n", commitOptions{})
+	checkFatal(t, err)
+
+	branchA, err := repo.LookupBranch("branch-a", BranchLocal)
+	checkFatal(t, err)
+	onto, err := repo.AnnotatedCommitFromRef(branchA.Reference)
+	checkFatal(t, err)
+
+	// We then rebase "branch-b" onto "branch-a" in-memory, which should result
+	// in a conflict.
+	rebase, err := repo.InitRebase(nil, nil, onto, &RebaseOptions{InMemory: 1})
+	checkFatal(t, err)
+
+	_, err = rebase.Next()
+	checkFatal(t, err)
+
+	index, err := rebase.InmemoryIndex()
+	checkFatal(t, err)
+
+	// We simply resolve the conflict and commit the rebase.
+	if !index.HasConflicts() {
+		t.Fatal("expected index to have conflicts")
+	}
+
+	conflict, err := index.Conflict("common-file")
+	checkFatal(t, err)
+
+	resolvedBlobID, err := repo.CreateBlobFromBuffer([]byte("resolved contents"))
+	checkFatal(t, err)
+
+	resolvedEntry := *conflict.Our
+	resolvedEntry.Id = resolvedBlobID
+	checkFatal(t, index.Add(&resolvedEntry))
+	checkFatal(t, index.RemoveConflict("common-file"))
+
+	var commitID Oid
+	checkFatal(t, rebase.Commit(&commitID, signature(), signature(), "rebased message"))
+	checkFatal(t, rebase.Finish())
+
+	// And then assert that we can look up the new merge commit, and that the
+	// "common-file" has the expected contents.
+	commit, err := repo.LookupCommit(&commitID)
+	checkFatal(t, err)
+	if commit.Message() != "rebased message" {
+		t.Fatalf("unexpected commit message %q", commit.Message())
+	}
+
+	tree, err := commit.Tree()
+	checkFatal(t, err)
+
+	blob, err := repo.LookupBlob(tree.EntryByName("common-file").Id)
+	checkFatal(t, err)
+	if string(blob.Contents()) != "resolved contents" {
+		t.Fatalf("unexpected resolved blob contents %q", string(blob.Contents()))
+	}
+}
+
+func TestRebaseAbort(t *testing.T) {
+	// TEST DATA
+
+	// Inputs
+	branchName := "emile"
+	masterCommit := "something"
+	emileCommits := []string{
+		"fou",
+		"barre",
+	}
+
+	// Outputs
+	expectedHistory := []string{
+		"Test rebase, Baby! " + emileCommits[1],
+		"Test rebase, Baby! " + emileCommits[0],
+		"This is a commit\n",
+	}
+
+	// TEST
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+	seedTestRepo(t, repo)
+
+	// Setup a repo with 2 branches and a different tree
+	err := setupRepoForRebase(repo, masterCommit, branchName, commitOptions{})
+	checkFatal(t, err)
+
+	// Create several commits in emile
+	for _, commit := range emileCommits {
+		_, err = commitSomething(repo, commit, commit, commitOptions{})
+		checkFatal(t, err)
+	}
+
+	// Check history
+	actualHistory, err := commitMsgsList(repo)
+	checkFatal(t, err)
+	assertStringList(t, expectedHistory, actualHistory)
+
+	// Rebase onto master
+	rebase, err := performRebaseOnto(repo, "master", nil)
+	checkFatal(t, err)
+	defer rebase.Free()
+
+	// Abort rebase
+	rebase.Abort()
+
+	// Check history is still the same
+	actualHistory, err = commitMsgsList(repo)
+	checkFatal(t, err)
+	assertStringList(t, expectedHistory, actualHistory)
+}
+
+func TestRebaseNoConflicts(t *testing.T) {
+	// TEST DATA
+
+	// Inputs
+	branchName := "emile"
+	masterCommit := "something"
+	emileCommits := []string{
+		"fou",
+		"barre",
+		"ouich",
+	}
+
+	// Outputs
+	expectedHistory := []string{
+		"Test rebase, Baby! " + emileCommits[2],
+		"Test rebase, Baby! " + emileCommits[1],
+		"Test rebase, Baby! " + emileCommits[0],
+		"Test rebase, Baby! " + masterCommit,
+		"This is a commit\n",
+	}
+
+	// TEST
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+	seedTestRepo(t, repo)
+
+	// Try to open existing rebase
+	oRebase, err := repo.OpenRebase(nil)
+	if err == nil {
+		t.Fatal("Did not expect to find a rebase in progress")
+	}
+
+	// Setup a repo with 2 branches and a different tree
+	err = setupRepoForRebase(repo, masterCommit, branchName, commitOptions{})
+	checkFatal(t, err)
+
+	// Create several commits in emile
+	for _, commit := range emileCommits {
+		_, err = commitSomething(repo, commit, commit, commitOptions{})
+		checkFatal(t, err)
+	}
+
+	// Rebase onto master
+	rebase, err := performRebaseOnto(repo, "master", nil)
+	checkFatal(t, err)
+	defer rebase.Free()
+
+	// Open existing rebase
+	oRebase, err = repo.OpenRebase(nil)
+	checkFatal(t, err)
+	defer oRebase.Free()
+	if oRebase == nil {
+		t.Fatal("Expected to find an existing rebase in progress")
+	}
+
+	// Finish the rebase properly
+	err = rebase.Finish()
+	checkFatal(t, err)
+
+	// Check no more rebase is in progress
+	oRebase, err = repo.OpenRebase(nil)
+	if err == nil {
+		t.Fatal("Did not expect to find a rebase in progress")
+	}
+
+	// Check history is in correct order
+	actualHistory, err := commitMsgsList(repo)
+	checkFatal(t, err)
+	assertStringList(t, expectedHistory, actualHistory)
+}
+
+func TestRebaseGpgSigned(t *testing.T) {
+	// TEST DATA
+
+	entity, err := openpgp.NewEntity("Namey mcnameface", "test comment", "test@example.com", nil)
+	checkFatal(t, err)
+
+	rebaseOpts, err := DefaultRebaseOptions()
+	checkFatal(t, err)
+
+	signCommitContent := func(commitContent string) (string, string, error) {
+		cipherText := new(bytes.Buffer)
+		err := openpgp.ArmoredDetachSignText(cipherText, entity, strings.NewReader(commitContent), &packet.Config{})
+		if err != nil {
+			return "", "", errors.New("error signing payload")
+		}
+
+		return cipherText.String(), "", nil
+	}
+	rebaseOpts.CommitSigningCallback = signCommitContent
+
+	commitOpts := commitOptions{
+		CommitSigningCallback: signCommitContent,
+	}
+
+	// Inputs
+	branchName := "emile"
+	masterCommit := "something"
+	emileCommits := []string{
+		"fou",
+		"barre",
+		"ouich",
+	}
+
+	// Outputs
+	expectedHistory := []string{
+		"Test rebase, Baby! " + emileCommits[2],
+		"Test rebase, Baby! " + emileCommits[1],
+		"Test rebase, Baby! " + emileCommits[0],
+		"Test rebase, Baby! " + masterCommit,
+		"This is a commit\n",
+	}
+
+	// TEST
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+	seedTestRepoOpt(t, repo, commitOpts)
+
+	// Try to open existing rebase
+	_, err = repo.OpenRebase(nil)
+	if err == nil {
+		t.Fatal("Did not expect to find a rebase in progress")
+	}
+
+	// Setup a repo with 2 branches and a different tree
+	err = setupRepoForRebase(repo, masterCommit, branchName, commitOpts)
+	checkFatal(t, err)
+
+	// Create several commits in emile
+	for _, commit := range emileCommits {
+		_, err = commitSomething(repo, commit, commit, commitOpts)
+		checkFatal(t, err)
+	}
+
+	// Rebase onto master
+	rebase, err := performRebaseOnto(repo, "master", &rebaseOpts)
+	checkFatal(t, err)
+	defer rebase.Free()
+
+	// Finish the rebase properly
+	err = rebase.Finish()
+	checkFatal(t, err)
+
+	// Check history is in correct order
+	actualHistory, err := commitMsgsList(repo)
+	checkFatal(t, err)
+	assertStringList(t, expectedHistory, actualHistory)
+
+	checkAllCommitsSigned(t, entity, repo)
+}
+
+func checkAllCommitsSigned(t *testing.T, entity *openpgp.Entity, repo *Repository) {
+	head, err := headCommit(repo)
+	checkFatal(t, err)
+	defer head.Free()
+
+	parent := head
+
+	err = checkCommitSigned(t, entity, parent)
+	checkFatal(t, err)
+
+	for parent.ParentCount() != 0 {
+		parent = parent.Parent(0)
+		defer parent.Free()
+
+		err = checkCommitSigned(t, entity, parent)
+		checkFatal(t, err)
+	}
+}
+
+func checkCommitSigned(t *testing.T, entity *openpgp.Entity, commit *Commit) error {
+	t.Helper()
+
+	signature, signedData, err := commit.ExtractSignature()
+	if err != nil {
+		t.Logf("No signature on commit\n%s", commit.ContentToSign())
+		return err
+	}
+
+	_, err = openpgp.CheckArmoredDetachedSignature(openpgp.EntityList{entity}, strings.NewReader(signedData), bytes.NewBufferString(signature), nil)
+	if err != nil {
+		t.Logf("Commit is not signed correctly\n%s", commit.ContentToSign())
+		return err
+	}
+
+	return nil
+}
+
+// Utils
+func setupRepoForRebase(repo *Repository, masterCommit, branchName string, commitOpts commitOptions) error {
+	// Create a new branch from master
+	err := createBranch(repo, branchName)
+	if err != nil {
+		return err
+	}
+
+	// Create a commit in master
+	_, err = commitSomething(repo, masterCommit, masterCommit, commitOpts)
+	if err != nil {
+		return err
+	}
+
+	// Switch to emile
+	err = repo.SetHead("refs/heads/" + branchName)
+	if err != nil {
+		return err
+	}
+
+	// Check master commit is not in emile branch
+	if entryExists(repo, masterCommit) {
+		return errors.New(masterCommit + " entry should not exist in " + branchName + " branch.")
+	}
+
+	return nil
+}
+
+func performRebaseOnto(repo *Repository, branch string, rebaseOpts *RebaseOptions) (*Rebase, error) {
+	master, err := repo.LookupBranch(branch, BranchLocal)
+	if err != nil {
+		return nil, err
+	}
+	defer master.Free()
+
+	onto, err := repo.AnnotatedCommitFromRef(master.Reference)
+	if err != nil {
+		return nil, err
+	}
+	defer onto.Free()
+
+	// Init rebase
+	rebase, err := repo.InitRebase(nil, nil, onto, rebaseOpts)
+	if err != nil {
+		return nil, err
+	}
+
+	// Check no operation has been started yet
+	rebaseOperationIndex, err := rebase.CurrentOperationIndex()
+	if rebaseOperationIndex != RebaseNoOperation && err != ErrRebaseNoOperation {
+		return nil, errors.New("No operation should have been started yet")
+	}
+
+	// Iterate in rebase operations regarding operation count
+	opCount := int(rebase.OperationCount())
+	for op := 0; op < opCount; op++ {
+		operation, err := rebase.Next()
+		if err != nil {
+			return nil, err
+		}
+
+		// Check operation index is correct
+		rebaseOperationIndex, err = rebase.CurrentOperationIndex()
+		if int(rebaseOperationIndex) != op {
+			return nil, errors.New("Bad operation index")
+		}
+		if !operationsAreEqual(rebase.OperationAt(uint(op)), operation) {
+			return nil, errors.New("Rebase operations should be equal")
+		}
+
+		// Get current rebase operation created commit
+		commit, err := repo.LookupCommit(operation.Id)
+		if err != nil {
+			return nil, err
+		}
+		defer commit.Free()
+
+		// Apply commit
+		err = rebase.Commit(operation.Id, signature(), signature(), commit.Message())
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return rebase, nil
+}
+
+func operationsAreEqual(l, r *RebaseOperation) bool {
+	return l.Exec == r.Exec && l.Type == r.Type && l.Id.String() == r.Id.String()
+}
+
+func createBranch(repo *Repository, branch string) error {
+	commit, err := headCommit(repo)
+	if err != nil {
+		return err
+	}
+	defer commit.Free()
+	_, err = repo.CreateBranch(branch, commit, false)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func signature() *Signature {
+	return &Signature{
+		Name:  "Emile",
+		Email: "emile@emile.com",
+		When:  time.Now(),
+	}
+}
+
+func headCommit(repo *Repository) (*Commit, error) {
+	head, err := repo.Head()
+	if err != nil {
+		return nil, err
+	}
+	defer head.Free()
+
+	commit, err := repo.LookupCommit(head.Target())
+	if err != nil {
+		return nil, err
+	}
+
+	return commit, nil
+}
+
+func headTree(repo *Repository) (*Tree, error) {
+	headCommit, err := headCommit(repo)
+	if err != nil {
+		return nil, err
+	}
+	defer headCommit.Free()
+
+	tree, err := headCommit.Tree()
+	if err != nil {
+		return nil, err
+	}
+
+	return tree, nil
+}
+
+func commitSomething(repo *Repository, something, content string, commitOpts commitOptions) (*Oid, error) {
+	headCommit, err := headCommit(repo)
+	if err != nil {
+		return nil, err
+	}
+	defer headCommit.Free()
+
+	index, err := NewIndex()
+	if err != nil {
+		return nil, err
+	}
+	defer index.Free()
+
+	blobOID, err := repo.CreateBlobFromBuffer([]byte(content))
+	if err != nil {
+		return nil, err
+	}
+
+	entry := &IndexEntry{
+		Mode: FilemodeBlob,
+		Id:   blobOID,
+		Path: something,
+	}
+
+	if err := index.Add(entry); err != nil {
+		return nil, err
+	}
+
+	newTreeOID, err := index.WriteTreeTo(repo)
+	if err != nil {
+		return nil, err
+	}
+
+	newTree, err := repo.LookupTree(newTreeOID)
+	if err != nil {
+		return nil, err
+	}
+	defer newTree.Free()
+
+	commit, err := repo.CreateCommit("HEAD", signature(), signature(), "Test rebase, Baby! "+something, newTree, headCommit)
+	if err != nil {
+		return nil, err
+	}
+
+	if commitOpts.CommitSigningCallback != nil {
+		commit, err := repo.LookupCommit(commit)
+		if err != nil {
+			return nil, err
+		}
+
+		oid, err := commit.WithSignatureUsing(commitOpts.CommitSigningCallback)
+		if err != nil {
+			return nil, err
+		}
+		newCommit, err := repo.LookupCommit(oid)
+		if err != nil {
+			return nil, err
+		}
+		head, err := repo.Head()
+		if err != nil {
+			return nil, err
+		}
+		_, err = repo.References.Create(
+			head.Name(),
+			newCommit.Id(),
+			true,
+			"repoint to signed commit",
+		)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	checkoutOpts := &CheckoutOptions{
+		Strategy: CheckoutRemoveUntracked | CheckoutForce,
+	}
+	err = repo.CheckoutIndex(index, checkoutOpts)
+	if err != nil {
+		return nil, err
+	}
+
+	return commit, nil
+}
+
+func entryExists(repo *Repository, file string) bool {
+	headTree, err := headTree(repo)
+	if err != nil {
+		return false
+	}
+	defer headTree.Free()
+
+	_, err = headTree.EntryByPath(file)
+
+	return err == nil
+}
+
+func commitMsgsList(repo *Repository) ([]string, error) {
+	head, err := headCommit(repo)
+	if err != nil {
+		return nil, err
+	}
+	defer head.Free()
+
+	var commits []string
+
+	parent := head.Parent(0)
+	defer parent.Free()
+	commits = append(commits, head.Message(), parent.Message())
+
+	for parent.ParentCount() != 0 {
+		parent = parent.Parent(0)
+		defer parent.Free()
+		commits = append(commits, parent.Message())
+	}
+
+	return commits, nil
+}
+
+func assertStringList(t *testing.T, expected, actual []string) {
+	if len(expected) != len(actual) {
+		t.Fatal("Lists are not the same size, expected " + strconv.Itoa(len(expected)) +
+			", got " + strconv.Itoa(len(actual)))
+	}
+	for index, element := range expected {
+		if element != actual[index] {
+			t.Error("Expected element " + strconv.Itoa(index) + " to be " + element + ", got " + actual[index])
+		}
+	}
+}

refdb.go

@@ -0,0 +1,64 @@
+package git
+
+/*
+#include <git2.h>
+#include <git2/sys/refdb_backend.h>
+
+extern void _go_git_refdb_backend_free(git_refdb_backend *backend);
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+type Refdb struct {
+	doNotCompare
+	ptr *C.git_refdb
+	r   *Repository
+}
+
+type RefdbBackend struct {
+	doNotCompare
+	ptr *C.git_refdb_backend
+}
+
+func (v *Repository) NewRefdb() (refdb *Refdb, err error) {
+	var ptr *C.git_refdb
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_refdb_new(&ptr, v.ptr)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	refdb = &Refdb{ptr: ptr, r: v}
+	runtime.SetFinalizer(refdb, (*Refdb).Free)
+	return refdb, nil
+}
+
+func NewRefdbBackendFromC(ptr unsafe.Pointer) (backend *RefdbBackend) {
+	backend = &RefdbBackend{ptr: (*C.git_refdb_backend)(ptr)}
+	return backend
+}
+
+func (v *Refdb) SetBackend(backend *RefdbBackend) (err error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_refdb_set_backend(v.ptr, backend.ptr)
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(backend)
+	if ret < 0 {
+		backend.Free()
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (v *RefdbBackend) Free() {
+	runtime.SetFinalizer(v, nil)
+	C._go_git_refdb_backend_free(v.ptr)
+}

reference.go

@@ -1,9 +1,7 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
 */
 import "C"
 import (
@@ -12,100 +10,353 @@ import (
 )
 
 type ReferenceType int
+
 const (
 	ReferenceSymbolic ReferenceType = C.GIT_REF_SYMBOLIC
-	ReferenceOid                    = C.GIT_REF_OID
+	ReferenceOid      ReferenceType = C.GIT_REF_OID
 )
 
 type Reference struct {
-	ptr *C.git_reference
+	doNotCompare
+	ptr  *C.git_reference
+	repo *Repository
 }
 
-func newReferenceFromC(ptr *C.git_reference) *Reference {
-	ref := &Reference{ptr}
-	runtime.SetFinalizer(ref, (*Reference).Free)
-
-	return ref
+type ReferenceCollection struct {
+	doNotCompare
+	repo *Repository
 }
 
-func (v *Reference) SetSymbolicTarget(target string) (*Reference, error) {
+func (c *ReferenceCollection) Lookup(name string) (*Reference, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
 	var ptr *C.git_reference
-	ctarget := C.CString(target)
-	defer C.free(unsafe.Pointer(ctarget))
 
-	ret := C.git_reference_symbolic_set_target(&ptr, v.ptr, ctarget)
-	if ret < 0 {
-		return nil, LastError()
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_reference_lookup(&ptr, c.repo.ptr, cname)
+	runtime.KeepAlive(c)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
 	}
 
-	return newReferenceFromC(ptr), nil
+	return newReferenceFromC(ptr, c.repo), nil
 }
 
-func (v *Reference) SetTarget(target *Oid) (*Reference, error) {
-	var ptr *C.git_reference
-
-	ret := C.git_reference_set_target(&ptr, v.ptr, target.toC())
-	if ret < 0 {
-		return nil, LastError()
-	}
-
-	return newReferenceFromC(ptr), nil
-}
-
-func (v *Reference) Resolve() (*Reference, error) {
-	var ptr *C.git_reference
-
-	ret := C.git_reference_resolve(&ptr, v.ptr)
-	if ret < 0 {
-		return nil, LastError()
-	}
-
-	return newReferenceFromC(ptr), nil
-}
-
-func (v *Reference) Rename(name string, force bool) (*Reference, error) {
-	var ptr *C.git_reference
+func (c *ReferenceCollection) Create(name string, id *Oid, force bool, msg string) (*Reference, error) {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
 
-	ret := C.git_reference_rename(&ptr, v.ptr, cname, cbool(force))
-
-	if ret < 0 {
-		return nil, LastError()
+	var cmsg *C.char
+	if msg == "" {
+		cmsg = nil
+	} else {
+		cmsg = C.CString(msg)
+		defer C.free(unsafe.Pointer(cmsg))
 	}
 
-	return newReferenceFromC(ptr), nil
-}
+	var ptr *C.git_reference
 
-func (v *Reference) Target() *Oid {
-	return newOidFromC(C.git_reference_target(v.ptr))
-}
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
 
-func (v *Reference) SymbolicTarget() string {
-	cstr := C.git_reference_symbolic_target(v.ptr)
-	if cstr == nil {
-		return ""
+	ecode := C.git_reference_create(&ptr, c.repo.ptr, cname, id.toC(), cbool(force), cmsg)
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(id)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
 	}
 
-	return C.GoString(cstr)
+	return newReferenceFromC(ptr, c.repo), nil
 }
 
-func (v *Reference) Delete() error {
-	ret := C.git_reference_delete(v.ptr)
+func (c *ReferenceCollection) CreateSymbolic(name, target string, force bool, msg string) (*Reference, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
 
+	ctarget := C.CString(target)
+	defer C.free(unsafe.Pointer(ctarget))
+
+	var cmsg *C.char
+	if msg == "" {
+		cmsg = nil
+	} else {
+		cmsg = C.CString(msg)
+		defer C.free(unsafe.Pointer(cmsg))
+	}
+
+	var ptr *C.git_reference
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_reference_symbolic_create(&ptr, c.repo.ptr, cname, ctarget, cbool(force), cmsg)
+	runtime.KeepAlive(c)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newReferenceFromC(ptr, c.repo), nil
+}
+
+// EnsureLog ensures that there is a reflog for the given reference
+// name and creates an empty one if necessary.
+func (c *ReferenceCollection) EnsureLog(name string) error {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_reference_ensure_log(c.repo.ptr, cname)
+	runtime.KeepAlive(c)
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 
 	return nil
 }
 
+// HasLog returns whether there is a reflog for the given reference
+// name
+func (c *ReferenceCollection) HasLog(name string) (bool, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_reference_has_log(c.repo.ptr, cname)
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+
+	return ret == 1, nil
+}
+
+// Dwim looks up a reference by DWIMing its short name
+func (c *ReferenceCollection) Dwim(name string) (*Reference, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_reference
+	ret := C.git_reference_dwim(&ptr, c.repo.ptr, cname)
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newReferenceFromC(ptr, c.repo), nil
+}
+
+func newReferenceFromC(ptr *C.git_reference, repo *Repository) *Reference {
+	ref := &Reference{ptr: ptr, repo: repo}
+	runtime.SetFinalizer(ref, (*Reference).Free)
+	return ref
+}
+
+func (v *Reference) SetSymbolicTarget(target string, msg string) (*Reference, error) {
+	var ptr *C.git_reference
+
+	ctarget := C.CString(target)
+	defer C.free(unsafe.Pointer(ctarget))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var cmsg *C.char
+	if msg == "" {
+		cmsg = nil
+	} else {
+		cmsg = C.CString(msg)
+		defer C.free(unsafe.Pointer(cmsg))
+	}
+
+	ret := C.git_reference_symbolic_set_target(&ptr, v.ptr, ctarget, cmsg)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newReferenceFromC(ptr, v.repo), nil
+}
+
+func (v *Reference) SetTarget(target *Oid, msg string) (*Reference, error) {
+	var ptr *C.git_reference
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var cmsg *C.char
+	if msg == "" {
+		cmsg = nil
+	} else {
+		cmsg = C.CString(msg)
+		defer C.free(unsafe.Pointer(cmsg))
+	}
+
+	ret := C.git_reference_set_target(&ptr, v.ptr, target.toC(), cmsg)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newReferenceFromC(ptr, v.repo), nil
+}
+
+func (v *Reference) Resolve() (*Reference, error) {
+	var ptr *C.git_reference
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_reference_resolve(&ptr, v.ptr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newReferenceFromC(ptr, v.repo), nil
+}
+
+func (v *Reference) Rename(name string, force bool, msg string) (*Reference, error) {
+	var ptr *C.git_reference
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	var cmsg *C.char
+	if msg == "" {
+		cmsg = nil
+	} else {
+		cmsg = C.CString(msg)
+		defer C.free(unsafe.Pointer(cmsg))
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_reference_rename(&ptr, v.ptr, cname, cbool(force), cmsg)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newReferenceFromC(ptr, v.repo), nil
+}
+
+func (v *Reference) Target() *Oid {
+	ret := newOidFromC(C.git_reference_target(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
+}
+
+func (v *Reference) SymbolicTarget() string {
+	var ret string
+	cstr := C.git_reference_symbolic_target(v.ptr)
+
+	if cstr != nil {
+		return C.GoString(cstr)
+	}
+
+	runtime.KeepAlive(v)
+	return ret
+}
+
+func (v *Reference) Delete() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_reference_delete(v.ptr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (v *Reference) Peel(t ObjectType) (*Object, error) {
+	var cobj *C.git_object
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C.git_reference_peel(&cobj, v.ptr, C.git_object_t(t))
+	runtime.KeepAlive(v)
+	if err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return allocObject(cobj, v.repo), nil
+}
+
+// Owner returns a weak reference to the repository which owns this reference.
+// This won't keep the underlying repository alive, but it should still be
+// Freed.
+func (v *Reference) Owner() *Repository {
+	repo := newRepositoryFromC(C.git_reference_owner(v.ptr))
+	runtime.KeepAlive(v)
+	repo.weak = true
+	return repo
+}
+
+// Cmp compares v to ref2. It returns 0 on equality, otherwise a
+// stable sorting.
+func (v *Reference) Cmp(ref2 *Reference) int {
+	ret := int(C.git_reference_cmp(v.ptr, ref2.ptr))
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(ref2)
+	return ret
+}
+
+// Shorthand returns a "human-readable" short reference name.
+func (v *Reference) Shorthand() string {
+	ret := C.GoString(C.git_reference_shorthand(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
+}
+
+// Name returns the full name of v.
 func (v *Reference) Name() string {
-	return C.GoString(C.git_reference_name(v.ptr))
+	ret := C.GoString(C.git_reference_name(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) Type() ReferenceType {
-	return ReferenceType(C.git_reference_type(v.ptr))
+	ret := ReferenceType(C.git_reference_type(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
+}
+
+func (v *Reference) IsBranch() bool {
+	ret := C.git_reference_is_branch(v.ptr) == 1
+	runtime.KeepAlive(v)
+	return ret
+}
+
+func (v *Reference) IsRemote() bool {
+	ret := C.git_reference_is_remote(v.ptr) == 1
+	runtime.KeepAlive(v)
+	return ret
+}
+
+func (v *Reference) IsTag() bool {
+	ret := C.git_reference_is_tag(v.ptr) == 1
+	runtime.KeepAlive(v)
+	return ret
+}
+
+// IsNote checks if the reference is a note.
+func (v *Reference) IsNote() bool {
+	ret := C.git_reference_is_note(v.ptr) == 1
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) Free() {
@@ -114,21 +365,45 @@ func (v *Reference) Free() {
 }
 
 type ReferenceIterator struct {
+	doNotCompare
 	ptr  *C.git_reference_iterator
 	repo *Repository
 }
 
+type ReferenceNameIterator struct {
+	doNotCompare
+	*ReferenceIterator
+}
+
 // NewReferenceIterator creates a new iterator over reference names
 func (repo *Repository) NewReferenceIterator() (*ReferenceIterator, error) {
 	var ptr *C.git_reference_iterator
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_reference_iterator_new(&ptr, repo.ptr)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
-	iter := &ReferenceIterator{repo: repo, ptr: ptr}
-	runtime.SetFinalizer(iter, (*ReferenceIterator).Free)
-	return iter, nil
+	return newReferenceIteratorFromC(ptr, repo), nil
+}
+
+// NewReferenceIterator creates a new branch iterator over reference names
+func (repo *Repository) NewReferenceNameIterator() (*ReferenceNameIterator, error) {
+	var ptr *C.git_reference_iterator
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_reference_iterator_new(&ptr, repo.ptr)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	iter := newReferenceIteratorFromC(ptr, repo)
+	return iter.Names(), nil
 }
 
 // NewReferenceIteratorGlob creates an iterator over reference names
@@ -138,46 +413,61 @@ func (repo *Repository) NewReferenceIteratorGlob(glob string) (*ReferenceIterato
 	cstr := C.CString(glob)
 	defer C.free(unsafe.Pointer(cstr))
 	var ptr *C.git_reference_iterator
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_reference_iterator_glob_new(&ptr, repo.ptr, cstr)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
-	iter := &ReferenceIterator{repo: repo, ptr: ptr}
-	runtime.SetFinalizer(iter, (*ReferenceIterator).Free)
-	return iter, nil
+	return newReferenceIteratorFromC(ptr, repo), nil
 }
 
-// Next retrieves the next reference name. If the iteration is over,
-// the returned error is git.ErrIterOver
-func (v *ReferenceIterator) NextName() (string, error) {
+func (i *ReferenceIterator) Names() *ReferenceNameIterator {
+	return &ReferenceNameIterator{ReferenceIterator: i}
+}
+
+// NextName retrieves the next reference name. If the iteration is over,
+// the returned error code is git.ErrorCodeIterOver
+func (v *ReferenceNameIterator) Next() (string, error) {
 	var ptr *C.char
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_reference_next_name(&ptr, v.ptr)
-	if ret == ITEROVER {
-		return "", ErrIterOver
-	}
 	if ret < 0 {
-		return "", LastError()
+		return "", MakeGitError(ret)
 	}
 
 	return C.GoString(ptr), nil
 }
 
-// Create a channel from the iterator. You can use range on the
-// returned channel to iterate over all the references names. The channel
-// will be closed in case any error is found.
-func (v *ReferenceIterator) NameIter() <-chan string {
-	ch := make(chan string)
-	go func() {
-		defer close(ch)
-		name, err := v.NextName()
-		for err == nil {
-			ch <- name
-			name, err = v.NextName()
-		}
-	}()
+// Next retrieves the next reference. If the iterationis over, the
+// returned error code is git.ErrorCodeIterOver
+func (v *ReferenceIterator) Next() (*Reference, error) {
+	var ptr *C.git_reference
 
-	return ch
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_reference_next(&ptr, v.ptr)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newReferenceFromC(ptr, v.repo), nil
+}
+
+func newReferenceIteratorFromC(ptr *C.git_reference_iterator, r *Repository) *ReferenceIterator {
+	iter := &ReferenceIterator{
+		ptr:  ptr,
+		repo: r,
+	}
+	runtime.SetFinalizer(iter, (*ReferenceIterator).Free)
+	return iter
 }
 
 // Free the reference iterator
@@ -185,3 +475,67 @@ func (v *ReferenceIterator) Free() {
 	runtime.SetFinalizer(v, nil)
 	C.git_reference_iterator_free(v.ptr)
 }
+
+// ReferenceNameIsValid returns whether the reference name is well-formed.
+//
+// Valid reference names must follow one of two patterns:
+//
+// 1. Top-level names must contain only capital letters and underscores,
+// and must begin and end with a letter. (e.g. "HEAD", "ORIG_HEAD").
+//
+// 2. Names prefixed with "refs/" can be almost anything. You must avoid
+// the characters '~', '^', ':', ' \ ', '?', '[', and '*', and the sequences
+// ".." and " @ {" which have special meaning to revparse.
+func ReferenceNameIsValid(name string) (bool, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var valid C.int
+	ret := C.git_reference_name_is_valid(&valid, cname)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+	return valid == 1, nil
+}
+
+const (
+	// This should match GIT_REFNAME_MAX in src/refs.h
+	_refnameMaxLength = C.size_t(1024)
+)
+
+type ReferenceFormat uint
+
+const (
+	ReferenceFormatNormal           ReferenceFormat = C.GIT_REFERENCE_FORMAT_NORMAL
+	ReferenceFormatAllowOnelevel    ReferenceFormat = C.GIT_REFERENCE_FORMAT_ALLOW_ONELEVEL
+	ReferenceFormatRefspecPattern   ReferenceFormat = C.GIT_REFERENCE_FORMAT_REFSPEC_PATTERN
+	ReferenceFormatRefspecShorthand ReferenceFormat = C.GIT_REFERENCE_FORMAT_REFSPEC_SHORTHAND
+)
+
+// ReferenceNormalizeName normalizes the reference name and checks validity.
+//
+// This will normalize the reference name by removing any leading slash '/'
+// characters and collapsing runs of adjacent slashes between name components
+// into a single slash.
+//
+// See git_reference_symbolic_create() for rules about valid names.
+func ReferenceNormalizeName(name string, flags ReferenceFormat) (string, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	buf := (*C.char)(C.malloc(_refnameMaxLength))
+	defer C.free(unsafe.Pointer(buf))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_reference_normalize_name(buf, _refnameMaxLength, cname, C.uint(flags))
+	if ecode < 0 {
+		return "", MakeGitError(ecode)
+	}
+
+	return C.GoString(buf), nil
+}

reference_test.go

@@ -1,7 +1,6 @@
 package git
 
 import (
-	"os"
 	"runtime"
 	"sort"
 	"testing"
@@ -9,19 +8,20 @@ import (
 )
 
 func TestRefModification(t *testing.T) {
+	t.Parallel()
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	commitId, treeId := seedTestRepo(t, repo)
 
-	_, err := repo.CreateReference("refs/tags/tree", treeId, true)
+	_, err := repo.References.Create("refs/tags/tree", treeId, true, "testTreeTag")
 	checkFatal(t, err)
 
-	tag, err := repo.LookupReference("refs/tags/tree")
+	tag, err := repo.References.Lookup("refs/tags/tree")
 	checkFatal(t, err)
 	checkRefType(t, tag, ReferenceOid)
 
-	ref, err := repo.LookupReference("HEAD")
+	ref, err := repo.References.Lookup("HEAD")
 	checkFatal(t, err)
 	checkRefType(t, ref, ReferenceSymbolic)
 
@@ -45,17 +45,18 @@ func TestRefModification(t *testing.T) {
 		t.Fatalf("Wrong ref target")
 	}
 
-	_, err = tag.Rename("refs/tags/renamed", false)
+	_, err = tag.Rename("refs/tags/renamed", false, "")
 	checkFatal(t, err)
-	tag, err = repo.LookupReference("refs/tags/renamed")
+	tag, err = repo.References.Lookup("refs/tags/renamed")
 	checkFatal(t, err)
 	checkRefType(t, ref, ReferenceOid)
 
 }
 
-func TestIterator(t *testing.T) {
+func TestReferenceIterator(t *testing.T) {
+	t.Parallel()
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	loc, err := time.LoadLocation("Europe/Berlin")
 	checkFatal(t, err)
@@ -78,13 +79,13 @@ func TestIterator(t *testing.T) {
 	commitId, err := repo.CreateCommit("HEAD", sig, sig, message, tree)
 	checkFatal(t, err)
 
-	_, err = repo.CreateReference("refs/heads/one", commitId, true)
+	_, err = repo.References.Create("refs/heads/one", commitId, true, "headOne")
 	checkFatal(t, err)
 
-	_, err = repo.CreateReference("refs/heads/two", commitId, true)
+	_, err = repo.References.Create("refs/heads/two", commitId, true, "headTwo")
 	checkFatal(t, err)
 
-	_, err = repo.CreateReference("refs/heads/three", commitId, true)
+	_, err = repo.References.Create("refs/heads/three", commitId, true, "headThree")
 	checkFatal(t, err)
 
 	iter, err := repo.NewReferenceIterator()
@@ -99,41 +100,155 @@ func TestIterator(t *testing.T) {
 	}
 
 	// test some manual iteration
-	name, err := iter.NextName()
+	nameIter := iter.Names()
+	name, err := nameIter.Next()
 	for err == nil {
 		list = append(list, name)
-		name, err = iter.NextName()
+		name, err = nameIter.Next()
 	}
-	if err != ErrIterOver {
+	if !IsErrorCode(err, ErrorCodeIterOver) {
 		t.Fatal("Iteration not over")
 	}
 
-
 	sort.Strings(list)
 	compareStringList(t, expected, list)
 
-	// test the channel iteration
-	list = []string{}
+	// test the iterator for full refs, rather than just names
 	iter, err = repo.NewReferenceIterator()
-	for name := range iter.NameIter() {
-		list = append(list, name)
+	checkFatal(t, err)
+	count := 0
+	_, err = iter.Next()
+	for err == nil {
+		count++
+		_, err = iter.Next()
+	}
+	if !IsErrorCode(err, ErrorCodeIterOver) {
+		t.Fatal("Iteration not over")
 	}
 
-	sort.Strings(list)
-	compareStringList(t, expected, list)
-
-	iter, err = repo.NewReferenceIteratorGlob("refs/heads/t*")
-	expected = []string{
-		"refs/heads/three",
-		"refs/heads/two",
+	if count != 4 {
+		t.Fatalf("Wrong number of references returned %v", count)
 	}
 
-	list = []string{}
-	for name := range iter.NameIter() {
-		list = append(list, name)
+}
+
+func TestReferenceOwner(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId, _ := seedTestRepo(t, repo)
+
+	ref, err := repo.References.Create("refs/heads/foo", commitId, true, "")
+	checkFatal(t, err)
+
+	owner := ref.Owner()
+	if owner == nil {
+		t.Fatal("nil owner")
 	}
 
-	compareStringList(t, expected, list)
+	if owner.ptr != repo.ptr {
+		t.Fatalf("bad ptr, expected %v have %v\n", repo.ptr, owner.ptr)
+	}
+}
+
+func TestUtil(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId, _ := seedTestRepo(t, repo)
+
+	ref, err := repo.References.Create("refs/heads/foo", commitId, true, "")
+	checkFatal(t, err)
+
+	ref2, err := repo.References.Dwim("foo")
+	checkFatal(t, err)
+
+	if ref.Cmp(ref2) != 0 {
+		t.Fatalf("foo didn't dwim to the right thing")
+	}
+
+	if ref.Shorthand() != "foo" {
+		t.Fatalf("refs/heads/foo has no foo shorthand")
+	}
+
+	hasLog, err := repo.References.HasLog("refs/heads/foo")
+	checkFatal(t, err)
+	if !hasLog {
+		t.Fatalf("branches have logs by default")
+	}
+}
+
+func TestIsNote(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitID, _ := seedTestRepo(t, repo)
+
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Now(),
+	}
+
+	refname, err := repo.Notes.DefaultRef()
+	checkFatal(t, err)
+
+	_, err = repo.Notes.Create(refname, sig, sig, commitID, "This is a note", false)
+	checkFatal(t, err)
+
+	ref, err := repo.References.Lookup(refname)
+	checkFatal(t, err)
+
+	if !ref.IsNote() {
+		t.Fatalf("%s should be a note", ref.Name())
+	}
+
+	ref, err = repo.References.Create("refs/heads/foo", commitID, true, "")
+	checkFatal(t, err)
+
+	if ref.IsNote() {
+		t.Fatalf("%s should not be a note", ref.Name())
+	}
+}
+
+func TestReferenceNameIsValid(t *testing.T) {
+	t.Parallel()
+	valid, err := ReferenceNameIsValid("HEAD")
+	checkFatal(t, err)
+	if !valid {
+		t.Errorf("HEAD should be a valid reference name")
+	}
+	valid, err = ReferenceNameIsValid("HEAD1")
+	checkFatal(t, err)
+	if valid {
+		t.Errorf("HEAD1 should not be a valid reference name")
+	}
+}
+
+func TestReferenceNormalizeName(t *testing.T) {
+	t.Parallel()
+
+	ref, err := ReferenceNormalizeName("refs/heads//master", ReferenceFormatNormal)
+	checkFatal(t, err)
+
+	if ref != "refs/heads/master" {
+		t.Errorf("ReferenceNormalizeName(%q) = %q; want %q", "refs/heads//master", ref, "refs/heads/master")
+	}
+
+	ref, err = ReferenceNormalizeName("master", ReferenceFormatAllowOnelevel|ReferenceFormatRefspecShorthand)
+	checkFatal(t, err)
+
+	if ref != "master" {
+		t.Errorf("ReferenceNormalizeName(%q) = %q; want %q", "master", ref, "master")
+	}
+
+	ref, err = ReferenceNormalizeName("foo^", ReferenceFormatNormal)
+	if !IsErrorCode(err, ErrorCodeInvalidSpec) {
+		t.Errorf("foo^ should be invalid")
+	}
 }
 
 func compareStringList(t *testing.T, expected, actual []string) {
@@ -152,8 +267,7 @@ func checkRefType(t *testing.T, ref *Reference, kind ReferenceType) {
 	// The failure happens at wherever we were called, not here
 	_, file, line, ok := runtime.Caller(1)
 	if !ok {
-		t.Fatal()
+		t.Fatalf("Unable to get caller")
 	}
-
 	t.Fatalf("Wrong ref type at %v:%v; have %v, expected %v", file, line, ref.Type(), kind)
 }

refspec.go

@@ -0,0 +1,149 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+type Refspec struct {
+	doNotCompare
+	ptr *C.git_refspec
+}
+
+// ParseRefspec parses a given refspec string
+func ParseRefspec(input string, isFetch bool) (*Refspec, error) {
+	var ptr *C.git_refspec
+
+	cinput := C.CString(input)
+	defer C.free(unsafe.Pointer(cinput))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_refspec_parse(&ptr, cinput, cbool(isFetch))
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	spec := &Refspec{ptr: ptr}
+	runtime.SetFinalizer(spec, (*Refspec).Free)
+	return spec, nil
+}
+
+// Free releases a refspec object which has been created by ParseRefspec
+func (s *Refspec) Free() {
+	runtime.SetFinalizer(s, nil)
+	C.git_refspec_free(s.ptr)
+}
+
+// Direction returns the refspec's direction
+func (s *Refspec) Direction() ConnectDirection {
+	direction := C.git_refspec_direction(s.ptr)
+	return ConnectDirection(direction)
+}
+
+// Src returns the refspec's source specifier
+func (s *Refspec) Src() string {
+	var ret string
+	cstr := C.git_refspec_src(s.ptr)
+
+	if cstr != nil {
+		ret = C.GoString(cstr)
+	}
+
+	runtime.KeepAlive(s)
+	return ret
+}
+
+// Dst returns the refspec's destination specifier
+func (s *Refspec) Dst() string {
+	var ret string
+	cstr := C.git_refspec_dst(s.ptr)
+
+	if cstr != nil {
+		ret = C.GoString(cstr)
+	}
+
+	runtime.KeepAlive(s)
+	return ret
+}
+
+// Force returns the refspec's force-update setting
+func (s *Refspec) Force() bool {
+	force := C.git_refspec_force(s.ptr)
+	return force != 0
+}
+
+// String returns the refspec's string representation
+func (s *Refspec) String() string {
+	var ret string
+	cstr := C.git_refspec_string(s.ptr)
+
+	if cstr != nil {
+		ret = C.GoString(cstr)
+	}
+
+	runtime.KeepAlive(s)
+	return ret
+}
+
+// SrcMatches checks if a refspec's source descriptor matches a reference
+func (s *Refspec) SrcMatches(refname string) bool {
+	cname := C.CString(refname)
+	defer C.free(unsafe.Pointer(cname))
+
+	matches := C.git_refspec_src_matches(s.ptr, cname)
+	return matches != 0
+}
+
+// SrcMatches checks if a refspec's destination descriptor matches a reference
+func (s *Refspec) DstMatches(refname string) bool {
+	cname := C.CString(refname)
+	defer C.free(unsafe.Pointer(cname))
+
+	matches := C.git_refspec_dst_matches(s.ptr, cname)
+	return matches != 0
+}
+
+// Transform a reference to its target following the refspec's rules
+func (s *Refspec) Transform(refname string) (string, error) {
+	buf := C.git_buf{}
+
+	cname := C.CString(refname)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_refspec_transform(&buf, s.ptr, cname)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+	defer C.git_buf_dispose(&buf)
+
+	return C.GoString(buf.ptr), nil
+}
+
+// Rtransform converts a target reference to its source reference following the
+// refspec's rules
+func (s *Refspec) Rtransform(refname string) (string, error) {
+	buf := C.git_buf{}
+
+	cname := C.CString(refname)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_refspec_rtransform(&buf, s.ptr, cname)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+	defer C.git_buf_dispose(&buf)
+
+	return C.GoString(buf.ptr), nil
+}

refspec_test.go

@@ -0,0 +1,75 @@
+package git
+
+import (
+	"testing"
+)
+
+func TestRefspec(t *testing.T) {
+	t.Parallel()
+
+	const (
+		input      = "+refs/heads/*:refs/remotes/origin/*"
+		mainLocal  = "refs/heads/main"
+		mainRemote = "refs/remotes/origin/main"
+	)
+
+	refspec, err := ParseRefspec(input, true)
+	checkFatal(t, err)
+
+	// Accessors
+
+	s := refspec.String()
+	if s != input {
+		t.Errorf("expected string %q, got %q", input, s)
+	}
+
+	if d := refspec.Direction(); d != ConnectDirectionFetch {
+		t.Errorf("expected fetch refspec, got direction %v", d)
+	}
+
+	if pat, expected := refspec.Src(), "refs/heads/*"; pat != expected {
+		t.Errorf("expected refspec src %q, got %q", expected, pat)
+	}
+
+	if pat, expected := refspec.Dst(), "refs/remotes/origin/*"; pat != expected {
+		t.Errorf("expected refspec dst %q, got %q", expected, pat)
+	}
+
+	if !refspec.Force() {
+		t.Error("expected refspec force flag")
+	}
+
+	// SrcMatches
+
+	if !refspec.SrcMatches(mainLocal) {
+		t.Errorf("refspec source did not match %q", mainLocal)
+	}
+
+	if refspec.SrcMatches("refs/tags/v1.0") {
+		t.Error("refspec source matched under refs/tags")
+	}
+
+	// DstMatches
+
+	if !refspec.DstMatches(mainRemote) {
+		t.Errorf("refspec destination did not match %q", mainRemote)
+	}
+
+	if refspec.DstMatches("refs/tags/v1.0") {
+		t.Error("refspec destination matched under refs/tags")
+	}
+
+	// Transforms
+
+	fromLocal, err := refspec.Transform(mainLocal)
+	checkFatal(t, err)
+	if fromLocal != mainRemote {
+		t.Errorf("transform by refspec returned %s; expected %s", fromLocal, mainRemote)
+	}
+
+	fromRemote, err := refspec.Rtransform(mainRemote)
+	checkFatal(t, err)
+	if fromRemote != mainLocal {
+		t.Errorf("rtransform by refspec returned %s; expected %s", fromRemote, mainLocal)
+	}
+}

remote_test.go

@@ -0,0 +1,521 @@
+package git
+
+import (
+	"bytes"
+	"crypto/rand"
+	"crypto/rsa"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"os/exec"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/google/shlex"
+	"golang.org/x/crypto/ssh"
+)
+
+func TestListRemotes(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	remote, err := repo.Remotes.Create("test", "git://foo/bar")
+	checkFatal(t, err)
+	defer remote.Free()
+
+	expected := []string{
+		"test",
+	}
+
+	actual, err := repo.Remotes.List()
+	checkFatal(t, err)
+
+	compareStringList(t, expected, actual)
+}
+
+func assertHostname(cert *Certificate, valid bool, hostname string, t *testing.T) error {
+	if hostname != "github.com" {
+		t.Fatal("hostname does not match")
+		return errors.New("hostname does not match")
+	}
+
+	return nil
+}
+
+func TestCertificateCheck(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	remote, err := repo.Remotes.Create("origin", "https://github.com/libgit2/TestGitRepository")
+	checkFatal(t, err)
+	defer remote.Free()
+
+	options := FetchOptions{
+		RemoteCallbacks: RemoteCallbacks{
+			CertificateCheckCallback: func(cert *Certificate, valid bool, hostname string) error {
+				return assertHostname(cert, valid, hostname, t)
+			},
+		},
+	}
+
+	err = remote.Fetch([]string{}, &options, "")
+	checkFatal(t, err)
+}
+
+func TestRemoteConnect(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	remote, err := repo.Remotes.Create("origin", "https://github.com/libgit2/TestGitRepository")
+	checkFatal(t, err)
+	defer remote.Free()
+
+	err = remote.ConnectFetch(nil, nil, nil)
+	checkFatal(t, err)
+}
+
+func TestRemoteConnectOption(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	config, err := repo.Config()
+	checkFatal(t, err)
+	err = config.SetString("url.git@github.com:.insteadof", "https://github.com/")
+	checkFatal(t, err)
+
+	option, err := DefaultRemoteCreateOptions()
+	checkFatal(t, err)
+	option.Name = "origin"
+	option.Flags = RemoteCreateSkipInsteadof
+
+	remote, err := repo.Remotes.CreateWithOptions("https://github.com/libgit2/TestGitRepository", option)
+	checkFatal(t, err)
+	defer remote.Free()
+
+	err = remote.ConnectFetch(nil, nil, nil)
+	checkFatal(t, err)
+}
+
+func TestRemoteLs(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	remote, err := repo.Remotes.Create("origin", "https://github.com/libgit2/TestGitRepository")
+	checkFatal(t, err)
+	defer remote.Free()
+
+	err = remote.ConnectFetch(nil, nil, nil)
+	checkFatal(t, err)
+
+	heads, err := remote.Ls()
+	checkFatal(t, err)
+
+	if len(heads) == 0 {
+		t.Error("Expected remote heads")
+	}
+}
+
+func TestRemoteLsFiltering(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	remote, err := repo.Remotes.Create("origin", "https://github.com/libgit2/TestGitRepository")
+	checkFatal(t, err)
+	defer remote.Free()
+
+	err = remote.ConnectFetch(nil, nil, nil)
+	checkFatal(t, err)
+
+	heads, err := remote.Ls("master")
+	checkFatal(t, err)
+
+	if len(heads) != 1 {
+		t.Fatalf("Expected one head for master but I got %d", len(heads))
+	}
+
+	if heads[0].Id == nil {
+		t.Fatalf("Expected head to have an Id, but it's nil")
+	}
+
+	if heads[0].Name == "" {
+		t.Fatalf("Expected head to have a name, but it's empty")
+	}
+}
+
+func TestRemotePruneRefs(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	config, err := repo.Config()
+	checkFatal(t, err)
+	defer config.Free()
+
+	err = config.SetBool("remote.origin.prune", true)
+	checkFatal(t, err)
+
+	remote, err := repo.Remotes.Create("origin", "https://github.com/libgit2/TestGitRepository")
+	checkFatal(t, err)
+	defer remote.Free()
+
+	remote, err = repo.Remotes.Lookup("origin")
+	checkFatal(t, err)
+	defer remote.Free()
+
+	if !remote.PruneRefs() {
+		t.Fatal("Expected remote to be configured to prune references")
+	}
+}
+
+func TestRemotePrune(t *testing.T) {
+	t.Parallel()
+	remoteRepo := createTestRepo(t)
+	defer cleanupTestRepo(t, remoteRepo)
+
+	head, _ := seedTestRepo(t, remoteRepo)
+	commit, err := remoteRepo.LookupCommit(head)
+	checkFatal(t, err)
+	defer commit.Free()
+
+	remoteRef, err := remoteRepo.CreateBranch("test-prune", commit, true)
+	checkFatal(t, err)
+	defer remoteRef.Free()
+
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	config, err := repo.Config()
+	checkFatal(t, err)
+	defer config.Free()
+
+	remoteUrl := fmt.Sprintf("file://%s", remoteRepo.Workdir())
+	remote, err := repo.Remotes.Create("origin", remoteUrl)
+	checkFatal(t, err)
+	defer remote.Free()
+
+	err = remote.Fetch([]string{"test-prune"}, nil, "")
+	checkFatal(t, err)
+
+	ref, err := repo.References.Create("refs/remotes/origin/test-prune", head, true, "remote reference")
+	checkFatal(t, err)
+	defer ref.Free()
+
+	err = remoteRef.Delete()
+	checkFatal(t, err)
+
+	err = config.SetBool("remote.origin.prune", true)
+	checkFatal(t, err)
+
+	rr, err := repo.Remotes.Lookup("origin")
+	checkFatal(t, err)
+	defer rr.Free()
+
+	err = rr.ConnectFetch(nil, nil, nil)
+	checkFatal(t, err)
+
+	err = rr.Prune(nil)
+	checkFatal(t, err)
+
+	ref, err = repo.References.Lookup("refs/remotes/origin/test-prune")
+	if err == nil {
+		ref.Free()
+		t.Fatal("Expected error getting a pruned reference")
+	}
+}
+
+func TestRemoteCredentialsCalled(t *testing.T) {
+	t.Parallel()
+
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	remote, err := repo.Remotes.CreateAnonymous("https://github.com/libgit2/non-existent")
+	checkFatal(t, err)
+	defer remote.Free()
+
+	errNonExistent := errors.New("non-existent repository")
+	fetchOpts := FetchOptions{
+		RemoteCallbacks: RemoteCallbacks{
+			CredentialsCallback: func(url, username string, allowedTypes CredentialType) (*Credential, error) {
+				return nil, errNonExistent
+			},
+		},
+	}
+
+	err = remote.Fetch(nil, &fetchOpts, "fetch")
+	if err != errNonExistent {
+		t.Fatalf("remote.Fetch() = %v, want %v", err, errNonExistent)
+	}
+}
+
+func newChannelPipe(t *testing.T, w io.Writer, wg *sync.WaitGroup) (*os.File, error) {
+	pr, pw, err := os.Pipe()
+	if err != nil {
+		return nil, err
+	}
+
+	wg.Add(1)
+	go func() {
+		_, err := io.Copy(w, pr)
+		if err != nil && err != io.EOF {
+			t.Logf("Failed to copy: %v", err)
+		}
+		wg.Done()
+	}()
+
+	return pw, nil
+}
+
+func startSSHServer(t *testing.T, hostKey ssh.Signer, authorizedKeys []ssh.PublicKey) net.Listener {
+	t.Helper()
+
+	marshaledAuthorizedKeys := make([][]byte, len(authorizedKeys))
+	for i, authorizedKey := range authorizedKeys {
+		marshaledAuthorizedKeys[i] = authorizedKey.Marshal()
+	}
+
+	config := &ssh.ServerConfig{
+		PublicKeyCallback: func(c ssh.ConnMetadata, pubKey ssh.PublicKey) (*ssh.Permissions, error) {
+			marshaledPubKey := pubKey.Marshal()
+			for _, marshaledAuthorizedKey := range marshaledAuthorizedKeys {
+				if bytes.Equal(marshaledPubKey, marshaledAuthorizedKey) {
+					return &ssh.Permissions{
+						// Record the public key used for authentication.
+						Extensions: map[string]string{
+							"pubkey-fp": ssh.FingerprintSHA256(pubKey),
+						},
+					}, nil
+				}
+			}
+			t.Logf("unknown public key for %q:\n\t%+v\n\t%+v\n", c.User(), pubKey.Marshal(), authorizedKeys)
+			return nil, fmt.Errorf("unknown public key for %q", c.User())
+		},
+	}
+	config.AddHostKey(hostKey)
+
+	listener, err := net.Listen("tcp", "localhost:0")
+	if err != nil {
+		t.Fatalf("Failed to listen for connection: %v", err)
+	}
+
+	go func() {
+		nConn, err := listener.Accept()
+		if err != nil {
+			if strings.Contains(err.Error(), "use of closed network connection") {
+				return
+			}
+			t.Logf("Failed to accept incoming connection: %v", err)
+			return
+		}
+		defer nConn.Close()
+
+		conn, chans, reqs, err := ssh.NewServerConn(nConn, config)
+		if err != nil {
+			t.Logf("failed to handshake: %+v, %+v", conn, err)
+			return
+		}
+
+		// The incoming Request channel must be serviced.
+		go func() {
+			for newRequest := range reqs {
+				t.Logf("new request %v", newRequest)
+			}
+		}()
+
+		// Service only the first channel request
+		newChannel := <-chans
+		defer func() {
+			for newChannel := range chans {
+				t.Logf("new channel %v", newChannel)
+				newChannel.Reject(ssh.UnknownChannelType, "server closing")
+			}
+		}()
+
+		// Channels have a type, depending on the application level
+		// protocol intended. In the case of a shell, the type is
+		// "session" and ServerShell may be used to present a simple
+		// terminal interface.
+		if newChannel.ChannelType() != "session" {
+			newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
+			return
+		}
+		channel, requests, err := newChannel.Accept()
+		if err != nil {
+			t.Logf("Could not accept channel: %v", err)
+			return
+		}
+		defer channel.Close()
+
+		// Sessions have out-of-band requests such as "shell",
+		// "pty-req" and "env".  Here we handle only the
+		// "exec" request.
+		req := <-requests
+		if req.Type != "exec" {
+			req.Reply(false, nil)
+			return
+		}
+		// RFC 4254 Section 6.5.
+		var payload struct {
+			Command string
+		}
+		if err := ssh.Unmarshal(req.Payload, &payload); err != nil {
+			t.Logf("invalid payload on channel %v: %v", channel, err)
+			req.Reply(false, nil)
+			return
+		}
+		args, err := shlex.Split(payload.Command)
+		if err != nil {
+			t.Logf("invalid command on channel %v: %v", channel, err)
+			req.Reply(false, nil)
+			return
+		}
+		if len(args) < 2 || (args[0] != "git-upload-pack" && args[0] != "git-receive-pack") {
+			t.Logf("invalid command (%v) on channel %v: %v", args, channel, err)
+			req.Reply(false, nil)
+			return
+		}
+		req.Reply(true, nil)
+
+		go func(in <-chan *ssh.Request) {
+			for req := range in {
+				t.Logf("draining request %v", req)
+			}
+		}(requests)
+
+		// The first parameter is the (absolute) path of the repository.
+		args[1] = "./testdata" + args[1]
+
+		cmd := exec.Command(args[0], args[1:]...)
+		cmd.Stdin = channel
+		var wg sync.WaitGroup
+		stdoutPipe, err := newChannelPipe(t, channel, &wg)
+		if err != nil {
+			t.Logf("Failed to create stdout pipe: %v", err)
+			return
+		}
+		cmd.Stdout = stdoutPipe
+		stderrPipe, err := newChannelPipe(t, channel.Stderr(), &wg)
+		if err != nil {
+			t.Logf("Failed to create stderr pipe: %v", err)
+			return
+		}
+		cmd.Stderr = stderrPipe
+
+		go func() {
+			wg.Wait()
+			channel.CloseWrite()
+		}()
+
+		err = cmd.Start()
+		if err != nil {
+			t.Logf("Failed to start %v: %v", args, err)
+			return
+		}
+
+		// Once the process has started, we need to close the write end of the
+		// pipes from this process so that we can know when the child has done
+		// writing to it.
+		stdoutPipe.Close()
+		stderrPipe.Close()
+
+		timer := time.AfterFunc(5*time.Second, func() {
+			t.Log("process timed out, terminating")
+			cmd.Process.Kill()
+		})
+		defer timer.Stop()
+
+		err = cmd.Wait()
+		if err != nil {
+			t.Logf("Failed to run %v: %v", args, err)
+			return
+		}
+	}()
+	return listener
+}
+
+func TestRemoteSSH(t *testing.T) {
+	t.Parallel()
+	pubKeyUsername := "testuser"
+
+	hostPrivKey, err := rsa.GenerateKey(rand.Reader, 512)
+	if err != nil {
+		t.Fatalf("Failed to generate the host RSA private key: %v", err)
+	}
+	hostSigner, err := ssh.NewSignerFromKey(hostPrivKey)
+	if err != nil {
+		t.Fatalf("Failed to generate SSH hostSigner: %v", err)
+	}
+
+	privKey, err := rsa.GenerateKey(rand.Reader, 512)
+	if err != nil {
+		t.Fatalf("Failed to generate the user RSA private key: %v", err)
+	}
+	signer, err := ssh.NewSignerFromKey(privKey)
+	if err != nil {
+		t.Fatalf("Failed to generate SSH signer: %v", err)
+	}
+	// This is in the format "xx:xx:xx:...", so we remove the colons so that it
+	// matches the fmt.Sprintf() below.
+	// Note that not all libssh2 implementations support the SHA256 fingerprint,
+	// so we use MD5 here for testing.
+	publicKeyFingerprint := strings.Replace(ssh.FingerprintLegacyMD5(hostSigner.PublicKey()), ":", "", -1)
+
+	listener := startSSHServer(t, hostSigner, []ssh.PublicKey{signer.PublicKey()})
+	defer listener.Close()
+
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	certificateCheckCallbackCalled := false
+	fetchOpts := FetchOptions{
+		RemoteCallbacks: RemoteCallbacks{
+			CertificateCheckCallback: func(cert *Certificate, valid bool, hostname string) error {
+				hostkeyFingerprint := fmt.Sprintf("%x", cert.Hostkey.HashMD5[:])
+				if hostkeyFingerprint != publicKeyFingerprint {
+					return fmt.Errorf("server hostkey %q, want %q", hostkeyFingerprint, publicKeyFingerprint)
+				}
+				certificateCheckCallbackCalled = true
+				return nil
+			},
+			CredentialsCallback: func(url, username string, allowedTypes CredentialType) (*Credential, error) {
+				if allowedTypes&(CredentialTypeSSHKey|CredentialTypeSSHCustom|CredentialTypeSSHMemory) != 0 {
+					return NewCredentialSSHKeyFromSigner(pubKeyUsername, signer)
+				}
+				if (allowedTypes & CredentialTypeUsername) != 0 {
+					return NewCredentialUsername(pubKeyUsername)
+				}
+				return nil, fmt.Errorf("unknown credential type %+v", allowedTypes)
+			},
+		},
+	}
+
+	remote, err := repo.Remotes.Create(
+		"origin",
+		fmt.Sprintf("ssh://%s/TestGitRepository", listener.Addr().String()),
+	)
+	checkFatal(t, err)
+	defer remote.Free()
+
+	err = remote.Fetch(nil, &fetchOpts, "")
+	checkFatal(t, err)
+	if !certificateCheckCallbackCalled {
+		t.Fatalf("CertificateCheckCallback was not called")
+	}
+
+	heads, err := remote.Ls()
+	checkFatal(t, err)
+
+	if len(heads) == 0 {
+		t.Error("Expected remote heads")
+	}
+}

repository.go

@@ -1,169 +1,432 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
+#include <git2/sys/repository.h>
+#include <git2/sys/commit.h>
+#include <string.h>
 */
 import "C"
 import (
-	"unsafe"
 	"runtime"
+	"unsafe"
 )
 
 // Repository
 type Repository struct {
+	doNotCompare
 	ptr *C.git_repository
+	// Remotes represents the collection of remotes and can be
+	// used to add, remove and configure remotes for this
+	// repository.
+	Remotes RemoteCollection
+	// Submodules represents the collection of submodules and can
+	// be used to add, remove and configure submodules in this
+	// repository.
+	Submodules SubmoduleCollection
+	// References represents the collection of references and can
+	// be used to create, remove or update references for this repository.
+	References ReferenceCollection
+	// Notes represents the collection of notes and can be used to
+	// read, write and delete notes from this repository.
+	Notes NoteCollection
+	// Tags represents the collection of tags and can be used to create,
+	// list, iterate and remove tags in this repository.
+	Tags TagsCollection
+	// Stashes represents the collection of stashes and can be used to
+	// save, apply and iterate over stash states in this repository.
+	Stashes StashCollection
+
+	// weak indicates that a repository is a weak pointer and should not be
+	// freed.
+	weak bool
+}
+
+func newRepositoryFromC(ptr *C.git_repository) *Repository {
+	repo := &Repository{ptr: ptr}
+
+	repo.Remotes.repo = repo
+	repo.Remotes.remotes = make(map[*C.git_remote]*Remote)
+	repo.Submodules.repo = repo
+	repo.References.repo = repo
+	repo.Notes.repo = repo
+	repo.Tags.repo = repo
+	repo.Stashes.repo = repo
+
+	runtime.SetFinalizer(repo, (*Repository).Free)
+
+	return repo
 }
 
 func OpenRepository(path string) (*Repository, error) {
-	repo := new(Repository)
-
 	cpath := C.CString(path)
 	defer C.free(unsafe.Pointer(cpath))
 
-	ret := C.git_repository_open(&repo.ptr, cpath)
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_repository
+	ret := C.git_repository_open(&ptr, cpath)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
-	runtime.SetFinalizer(repo, (*Repository).Free)
-	return repo, nil
+	return newRepositoryFromC(ptr), nil
+}
+
+type RepositoryOpenFlag int
+
+const (
+	RepositoryOpenNoSearch RepositoryOpenFlag = C.GIT_REPOSITORY_OPEN_NO_SEARCH
+	RepositoryOpenCrossFs  RepositoryOpenFlag = C.GIT_REPOSITORY_OPEN_CROSS_FS
+	RepositoryOpenBare     RepositoryOpenFlag = C.GIT_REPOSITORY_OPEN_BARE
+	RepositoryOpenFromEnv  RepositoryOpenFlag = C.GIT_REPOSITORY_OPEN_FROM_ENV
+	RepositoryOpenNoDotGit RepositoryOpenFlag = C.GIT_REPOSITORY_OPEN_NO_DOTGIT
+)
+
+func OpenRepositoryExtended(path string, flags RepositoryOpenFlag, ceiling string) (*Repository, error) {
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	var cceiling *C.char = nil
+	if len(ceiling) > 0 {
+		cceiling = C.CString(ceiling)
+		defer C.free(unsafe.Pointer(cceiling))
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_repository
+	ret := C.git_repository_open_ext(&ptr, cpath, C.uint(flags), cceiling)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newRepositoryFromC(ptr), nil
 }
 
 func InitRepository(path string, isbare bool) (*Repository, error) {
-	repo := new(Repository)
-
 	cpath := C.CString(path)
 	defer C.free(unsafe.Pointer(cpath))
 
-	ret := C.git_repository_init(&repo.ptr, cpath, ucbool(isbare))
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_repository
+	ret := C.git_repository_init(&ptr, cpath, ucbool(isbare))
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
-	runtime.SetFinalizer(repo, (*Repository).Free)
-	return repo, nil
+	return newRepositoryFromC(ptr), nil
+}
+
+func NewRepositoryWrapOdb(odb *Odb) (repo *Repository, err error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_repository
+	ret := C.git_repository_wrap_odb(&ptr, odb.ptr)
+	runtime.KeepAlive(odb)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newRepositoryFromC(ptr), nil
+}
+
+func (v *Repository) SetRefdb(refdb *Refdb) {
+	C.git_repository_set_refdb(v.ptr, refdb.ptr)
+	runtime.KeepAlive(v)
 }
 
 func (v *Repository) Free() {
+	ptr := v.ptr
+	v.ptr = nil
 	runtime.SetFinalizer(v, nil)
-	C.git_repository_free(v.ptr)
+	v.Remotes.Free()
+	if v.weak {
+		return
+	}
+	C.git_repository_free(ptr)
 }
 
 func (v *Repository) Config() (*Config, error) {
 	config := new(Config)
 
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_repository_config(&config.ptr, v.ptr)
+	runtime.KeepAlive(v)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
+	runtime.SetFinalizer(config, (*Config).Free)
 	return config, nil
 }
 
+// SetConfig sets the configuration file for this repository.
+//
+// This configuration file will be used for all configuration queries involving
+// this repository.
+func (v *Repository) SetConfig(c *Config) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_repository_set_config(v.ptr, c.ptr)
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
 func (v *Repository) Index() (*Index, error) {
 	var ptr *C.git_index
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_repository_index(&ptr, v.ptr)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
-	return newIndexFromC(ptr), nil
+	return newIndexFromC(ptr, v), nil
 }
 
-func (v *Repository) lookupType(oid *Oid, t ObjectType) (Object, error) {
+func (v *Repository) lookupType(id *Oid, t ObjectType) (*Object, error) {
 	var ptr *C.git_object
-	ret := C.git_object_lookup(&ptr, v.ptr, oid.toC(), C.git_otype(t))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_object_lookup(&ptr, v.ptr, id.toC(), C.git_object_t(t))
+	runtime.KeepAlive(id)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
-	return allocObject(ptr), nil
+	return allocObject(ptr, v), nil
 }
 
-func (v *Repository) Lookup(oid *Oid) (Object, error) {
-	return v.lookupType(oid, ObjectAny)
+func (v *Repository) lookupPrefixType(id *Oid, prefix uint, t ObjectType) (*Object, error) {
+	var ptr *C.git_object
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_object_lookup_prefix(&ptr, v.ptr, id.toC(), C.size_t(prefix), C.git_object_t(t))
+	runtime.KeepAlive(id)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return allocObject(ptr, v), nil
 }
 
-func (v *Repository) LookupTree(oid *Oid) (*Tree, error) {
-	obj, err := v.lookupType(oid, ObjectTree)
+func (v *Repository) Lookup(id *Oid) (*Object, error) {
+	return v.lookupType(id, ObjectAny)
+}
+
+// LookupPrefix looks up an object by its OID given a prefix of its identifier.
+func (v *Repository) LookupPrefix(id *Oid, prefix uint) (*Object, error) {
+	return v.lookupPrefixType(id, prefix, ObjectAny)
+}
+
+func (v *Repository) LookupTree(id *Oid) (*Tree, error) {
+	obj, err := v.lookupType(id, ObjectTree)
 	if err != nil {
 		return nil, err
 	}
+	defer obj.Free()
 
-	return obj.(*Tree), nil
+	return obj.AsTree()
 }
 
-func (v *Repository) LookupCommit(oid *Oid) (*Commit, error) {
-	obj, err := v.lookupType(oid, ObjectCommit)
+// LookupPrefixTree looks up a tree by its OID given a prefix of its identifier.
+func (v *Repository) LookupPrefixTree(id *Oid, prefix uint) (*Tree, error) {
+	obj, err := v.lookupPrefixType(id, prefix, ObjectTree)
 	if err != nil {
 		return nil, err
 	}
+	defer obj.Free()
 
-	return obj.(*Commit), nil
+	return obj.AsTree()
 }
 
-func (v *Repository) LookupBlob(oid *Oid) (*Blob, error) {
-	obj, err := v.lookupType(oid, ObjectBlob)
+func (v *Repository) LookupCommit(id *Oid) (*Commit, error) {
+	obj, err := v.lookupType(id, ObjectCommit)
 	if err != nil {
 		return nil, err
 	}
+	defer obj.Free()
 
-	return obj.(*Blob), nil
+	return obj.AsCommit()
 }
 
-func (v *Repository) LookupReference(name string) (*Reference, error) {
-	cname := C.CString(name)
-	defer C.free(unsafe.Pointer(cname))
-	var ptr *C.git_reference
-
-	ecode := C.git_reference_lookup(&ptr, v.ptr, cname)
-	if ecode < 0 {
-		return nil, LastError()
+// LookupPrefixCommit looks up a commit by its OID given a prefix of its identifier.
+func (v *Repository) LookupPrefixCommit(id *Oid, prefix uint) (*Commit, error) {
+	obj, err := v.lookupPrefixType(id, prefix, ObjectCommit)
+	if err != nil {
+		return nil, err
 	}
+	defer obj.Free()
 
-	return newReferenceFromC(ptr), nil
+	return obj.AsCommit()
 }
 
-func (v *Repository) CreateReference(name string, oid *Oid, force bool) (*Reference, error) {
-	cname := C.CString(name)
-	defer C.free(unsafe.Pointer(cname))
-	var ptr *C.git_reference
-
-	ecode := C.git_reference_create(&ptr, v.ptr, cname, oid.toC(), cbool(force))
-	if ecode < 0 {
-		return nil, LastError()
+func (v *Repository) LookupBlob(id *Oid) (*Blob, error) {
+	obj, err := v.lookupType(id, ObjectBlob)
+	if err != nil {
+		return nil, err
 	}
+	defer obj.Free()
 
-	return newReferenceFromC(ptr), nil
+	return obj.AsBlob()
 }
 
-func (v *Repository) CreateSymbolicReference(name, target string, force bool) (*Reference, error) {
-	cname := C.CString(name)
-	defer C.free(unsafe.Pointer(cname))
-	ctarget := C.CString(target)
-	defer C.free(unsafe.Pointer(ctarget))
+// LookupPrefixBlob looks up a blob by its OID given a prefix of its identifier.
+func (v *Repository) LookupPrefixBlob(id *Oid, prefix uint) (*Blob, error) {
+	obj, err := v.lookupPrefixType(id, prefix, ObjectBlob)
+	if err != nil {
+		return nil, err
+	}
+	defer obj.Free()
+
+	return obj.AsBlob()
+}
+
+func (v *Repository) LookupTag(id *Oid) (*Tag, error) {
+	obj, err := v.lookupType(id, ObjectTag)
+	if err != nil {
+		return nil, err
+	}
+	defer obj.Free()
+
+	return obj.AsTag()
+}
+
+// LookupPrefixTag looks up a tag by its OID given a prefix of its identifier.
+func (v *Repository) LookupPrefixTag(id *Oid, prefix uint) (*Tag, error) {
+	obj, err := v.lookupPrefixType(id, prefix, ObjectTag)
+	if err != nil {
+		return nil, err
+	}
+	defer obj.Free()
+
+	return obj.AsTag()
+}
+
+func (v *Repository) Head() (*Reference, error) {
 	var ptr *C.git_reference
 
-	ecode := C.git_reference_symbolic_create(&ptr, v.ptr, cname, ctarget, cbool(force))
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_repository_head(&ptr, v.ptr)
 	if ecode < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ecode)
 	}
 
-	return newReferenceFromC(ptr), nil
+	return newReferenceFromC(ptr, v), nil
+}
+
+func (v *Repository) SetHead(refname string) error {
+	cname := C.CString(refname)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_repository_set_head(v.ptr, cname)
+	runtime.KeepAlive(v)
+	if ecode != 0 {
+		return MakeGitError(ecode)
+	}
+	return nil
+}
+
+func (v *Repository) SetHeadDetached(id *Oid) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_repository_set_head_detached(v.ptr, id.toC())
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(id)
+	if ecode != 0 {
+		return MakeGitError(ecode)
+	}
+	return nil
+}
+
+func (v *Repository) IsHeadDetached() (bool, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_repository_head_detached(v.ptr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+
+	return ret != 0, nil
+}
+
+func (v *Repository) IsHeadUnborn() (bool, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_repository_head_unborn(v.ptr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+	return ret != 0, nil
+}
+
+func (v *Repository) IsEmpty() (bool, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_repository_is_empty(v.ptr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+
+	return ret != 0, nil
+}
+
+func (v *Repository) IsShallow() (bool, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_repository_is_shallow(v.ptr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return false, MakeGitError(ret)
+	}
+	return ret != 0, nil
 }
 
 func (v *Repository) Walk() (*RevWalk, error) {
-	walk := new(RevWalk)
-	ecode := C.git_revwalk_new(&walk.ptr, v.ptr)
+
+	var walkPtr *C.git_revwalk
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_revwalk_new(&walkPtr, v.ptr)
 	if ecode < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ecode)
 	}
 
-	walk.repo = v
-	runtime.SetFinalizer(walk, freeRevWalk)
-	return walk, nil
+	return revWalkFromC(v, walkPtr), nil
 }
 
 func (v *Repository) CreateCommit(
@@ -172,8 +435,13 @@ func (v *Repository) CreateCommit(
 
 	oid := new(Oid)
 
-	cref := C.CString(refname)
-	defer C.free(unsafe.Pointer(cref))
+	var cref *C.char
+	if refname == "" {
+		cref = nil
+	} else {
+		cref = C.CString(refname)
+		defer C.free(unsafe.Pointer(cref))
+	}
 
 	cmsg := C.CString(message)
 	defer C.free(unsafe.Pointer(cmsg))
@@ -181,28 +449,204 @@ func (v *Repository) CreateCommit(
 	var cparents []*C.git_commit = nil
 	var parentsarg **C.git_commit = nil
 
-	nparents:= len(parents)
+	nparents := len(parents)
 	if nparents > 0 {
 		cparents = make([]*C.git_commit, nparents)
 		for i, v := range parents {
-			cparents[i] = v.ptr
+			cparents[i] = v.cast_ptr
 		}
 		parentsarg = &cparents[0]
 	}
 
-	authorSig := author.toC()
+	authorSig, err := author.toC()
+	if err != nil {
+		return nil, err
+	}
 	defer C.git_signature_free(authorSig)
 
-	committerSig := committer.toC()
+	committerSig, err := committer.toC()
+	if err != nil {
+		return nil, err
+	}
 	defer C.git_signature_free(committerSig)
 
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_commit_create(
 		oid.toC(), v.ptr, cref,
 		authorSig, committerSig,
-		nil, cmsg, tree.ptr, C.int(nparents), parentsarg)
+		nil, cmsg, tree.cast_ptr, C.size_t(nparents), parentsarg)
 
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(oid)
+	runtime.KeepAlive(parents)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
+	}
+
+	return oid, nil
+}
+
+// CreateCommitWithSignature creates a commit object from the given contents and
+// signature.
+func (v *Repository) CreateCommitWithSignature(
+	commitContent, signature, signatureField string,
+) (*Oid, error) {
+	cCommitContent := C.CString(commitContent)
+	defer C.free(unsafe.Pointer(cCommitContent))
+	var cSignature *C.char
+	if signature != "" {
+		cSignature = C.CString(string(signature))
+		defer C.free(unsafe.Pointer(cSignature))
+	}
+	var cSignatureField *C.char
+	if signatureField != "" {
+		cSignatureField = C.CString(string(signatureField))
+		defer C.free(unsafe.Pointer(cSignatureField))
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	oid := new(Oid)
+	ret := C.git_commit_create_with_signature(oid.toC(), v.ptr, cCommitContent, cSignature, cSignatureField)
+
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(oid)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return oid, nil
+}
+
+// CreateCommitBuffer creates a commit and write it into a buffer.
+func (v *Repository) CreateCommitBuffer(
+	author, committer *Signature,
+	messageEncoding MessageEncoding,
+	message string,
+	tree *Tree,
+	parents ...*Commit,
+) ([]byte, error) {
+	cmsg := C.CString(message)
+	defer C.free(unsafe.Pointer(cmsg))
+	var cencoding *C.char
+	// Since the UTF-8 encoding is the default, pass in nil whenever UTF-8 is
+	// provided. That will cause the commit to not have an explicit header for
+	// it.
+	if messageEncoding != MessageEncodingUTF8 && messageEncoding != MessageEncoding("") {
+		cencoding = C.CString(string(messageEncoding))
+		defer C.free(unsafe.Pointer(cencoding))
+	}
+
+	var cparents []*C.git_commit = nil
+	var parentsarg **C.git_commit = nil
+
+	nparents := len(parents)
+	if nparents > 0 {
+		cparents = make([]*C.git_commit, nparents)
+		for i, v := range parents {
+			cparents[i] = v.cast_ptr
+		}
+		parentsarg = &cparents[0]
+	}
+
+	authorSig, err := author.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(authorSig)
+
+	committerSig, err := committer.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(committerSig)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var buf C.git_buf
+	defer C.git_buf_dispose(&buf)
+	ret := C.git_commit_create_buffer(
+		&buf, v.ptr,
+		authorSig, committerSig,
+		cencoding, cmsg, tree.cast_ptr, C.size_t(nparents), parentsarg)
+
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(buf)
+	runtime.KeepAlive(parents)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return C.GoBytes(unsafe.Pointer(buf.ptr), C.int(buf.size)), nil
+}
+
+func (v *Repository) CreateCommitFromIds(
+	refname string, author, committer *Signature,
+	message string, tree *Oid, parents ...*Oid) (*Oid, error) {
+
+	oid := new(Oid)
+
+	var cref *C.char
+	if refname == "" {
+		cref = nil
+	} else {
+		cref = C.CString(refname)
+		defer C.free(unsafe.Pointer(cref))
+	}
+
+	cmsg := C.CString(message)
+	defer C.free(unsafe.Pointer(cmsg))
+
+	var parentsarg **C.git_oid = nil
+
+	nparents := len(parents)
+	if nparents > 0 {
+		// All this awful pointer arithmetic is needed to avoid passing a Go
+		// pointer to Go pointer into C. Other methods (like CreateCommits) are
+		// fine without this workaround because they are just passing Go pointers
+		// to C pointers, but arrays-of-pointers-to-git_oid are a bit special since
+		// both the array and the objects are allocated from Go.
+		var emptyOidPtr *C.git_oid
+		sizeofOidPtr := unsafe.Sizeof(emptyOidPtr)
+		parentsarg = (**C.git_oid)(C.calloc(C.size_t(uintptr(nparents)), C.size_t(sizeofOidPtr)))
+		defer C.free(unsafe.Pointer(parentsarg))
+		parentsptr := uintptr(unsafe.Pointer(parentsarg))
+		for _, v := range parents {
+			*(**C.git_oid)(unsafe.Pointer(parentsptr)) = v.toC()
+			parentsptr += sizeofOidPtr
+		}
+	}
+
+	authorSig, err := author.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(authorSig)
+
+	committerSig, err := committer.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(committerSig)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_commit_create_from_ids(
+		oid.toC(), v.ptr, cref,
+		authorSig, committerSig,
+		nil, cmsg, tree.toC(), C.size_t(nparents), parentsarg)
+
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(oid)
+	runtime.KeepAlive(tree)
+	runtime.KeepAlive(parents)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
 	}
 
 	return oid, nil
@@ -213,57 +657,220 @@ func (v *Odb) Free() {
 	C.git_odb_free(v.ptr)
 }
 
+func (v *Refdb) Free() {
+	runtime.SetFinalizer(v, nil)
+	C.git_refdb_free(v.ptr)
+}
+
 func (v *Repository) Odb() (odb *Odb, err error) {
 	odb = new(Odb)
-	if ret := C.git_repository_odb(&odb.ptr, v.ptr); ret < 0 {
-		return nil, LastError()
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_repository_odb(&odb.ptr, v.ptr)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
 	}
 
 	runtime.SetFinalizer(odb, (*Odb).Free)
-	return
+	return odb, nil
 }
 
 func (repo *Repository) Path() string {
-	return C.GoString(C.git_repository_path(repo.ptr))
+	s := C.GoString(C.git_repository_path(repo.ptr))
+	runtime.KeepAlive(repo)
+	return s
 }
 
-func (repo *Repository) IsBare() (bool) {
-	return C.git_repository_is_bare(repo.ptr) != 0
+func (repo *Repository) IsBare() bool {
+	ret := C.git_repository_is_bare(repo.ptr) != 0
+	runtime.KeepAlive(repo)
+	return ret
 }
 
 func (repo *Repository) Workdir() string {
-	return C.GoString(C.git_repository_workdir(repo.ptr))
+	s := C.GoString(C.git_repository_workdir(repo.ptr))
+	runtime.KeepAlive(repo)
+	return s
 }
 
 func (repo *Repository) SetWorkdir(workdir string, updateGitlink bool) error {
 	cstr := C.CString(workdir)
 	defer C.free(unsafe.Pointer(cstr))
 
-	if C.git_repository_set_workdir(repo.ptr, cstr, cbool(updateGitlink)) < 0 {
-		return LastError()
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if ret := C.git_repository_set_workdir(repo.ptr, cstr, cbool(updateGitlink)); ret < 0 {
+		return MakeGitError(ret)
 	}
+	runtime.KeepAlive(repo)
+
 	return nil
 }
 
 func (v *Repository) TreeBuilder() (*TreeBuilder, error) {
 	bld := new(TreeBuilder)
-	if ret := C.git_treebuilder_create(&bld.ptr, nil); ret < 0 {
-		return nil, LastError()
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if ret := C.git_treebuilder_new(&bld.ptr, v.ptr, nil); ret < 0 {
+		return nil, MakeGitError(ret)
 	}
 
+	runtime.SetFinalizer(bld, (*TreeBuilder).Free)
+
 	bld.repo = v
 	return bld, nil
 }
 
-func (v *Repository) RevparseSingle(spec string) (Object, error) {
-	cspec := C.CString(spec)
-	defer C.free(unsafe.Pointer(cspec))
+func (v *Repository) TreeBuilderFromTree(tree *Tree) (*TreeBuilder, error) {
+	bld := new(TreeBuilder)
 
-	var ptr *C.git_object
-	ecode := C.git_revparse_single(&ptr, v.ptr, cspec)
-	if ecode < 0 {
-		return nil, LastError()
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if ret := C.git_treebuilder_new(&bld.ptr, v.ptr, tree.cast_ptr); ret < 0 {
+		return nil, MakeGitError(ret)
 	}
+	runtime.SetFinalizer(bld, (*TreeBuilder).Free)
 
-	return allocObject(ptr), nil
+	bld.repo = v
+	return bld, nil
+}
+
+type RepositoryState int
+
+const (
+	RepositoryStateNone                 RepositoryState = C.GIT_REPOSITORY_STATE_NONE
+	RepositoryStateMerge                RepositoryState = C.GIT_REPOSITORY_STATE_MERGE
+	RepositoryStateRevert               RepositoryState = C.GIT_REPOSITORY_STATE_REVERT
+	RepositoryStateCherrypick           RepositoryState = C.GIT_REPOSITORY_STATE_CHERRYPICK
+	RepositoryStateBisect               RepositoryState = C.GIT_REPOSITORY_STATE_BISECT
+	RepositoryStateRebase               RepositoryState = C.GIT_REPOSITORY_STATE_REBASE
+	RepositoryStateRebaseInteractive    RepositoryState = C.GIT_REPOSITORY_STATE_REBASE_INTERACTIVE
+	RepositoryStateRebaseMerge          RepositoryState = C.GIT_REPOSITORY_STATE_REBASE_MERGE
+	RepositoryStateApplyMailbox         RepositoryState = C.GIT_REPOSITORY_STATE_APPLY_MAILBOX
+	RepositoryStateApplyMailboxOrRebase RepositoryState = C.GIT_REPOSITORY_STATE_APPLY_MAILBOX_OR_REBASE
+)
+
+func (r *Repository) State() RepositoryState {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := RepositoryState(C.git_repository_state(r.ptr))
+	runtime.KeepAlive(r)
+
+	return ret
+}
+
+func (r *Repository) StateCleanup() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cErr := C.git_repository_state_cleanup(r.ptr)
+	runtime.KeepAlive(r)
+	if cErr < 0 {
+		return MakeGitError(cErr)
+	}
+	return nil
+}
+
+func (r *Repository) AddGitIgnoreRules(rules string) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	crules := C.CString(rules)
+	defer C.free(unsafe.Pointer(crules))
+	ret := C.git_ignore_add_rule(r.ptr, crules)
+	runtime.KeepAlive(r)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (r *Repository) ClearGitIgnoreRules() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_ignore_clear_internal_rules(r.ptr)
+	runtime.KeepAlive(r)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+// Message retrieves git's prepared message.
+// Operations such as git revert/cherry-pick/merge with the -n option stop just
+// short of creating a commit with the changes and save their prepared message
+// in .git/MERGE_MSG so the next git-commit execution can present it to the
+// user for them to amend if they wish.
+//
+// Use this function to get the contents of this file. Don't forget to remove
+// the file after you create the commit.
+func (r *Repository) Message() (string, error) {
+	buf := C.git_buf{}
+	defer C.git_buf_dispose(&buf)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cErr := C.git_repository_message(&buf, r.ptr)
+	runtime.KeepAlive(r)
+	if cErr < 0 {
+		return "", MakeGitError(cErr)
+	}
+	return C.GoString(buf.ptr), nil
+}
+
+// RemoveMessage removes git's prepared message.
+func (r *Repository) RemoveMessage() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cErr := C.git_repository_message_remove(r.ptr)
+	runtime.KeepAlive(r)
+	if cErr < 0 {
+		return MakeGitError(cErr)
+	}
+	return nil
+}
+
+type RepositoryItem int
+
+const (
+	RepositoryItemGitDir     RepositoryItem = C.GIT_REPOSITORY_ITEM_GITDIR
+	RepositoryItemWorkDir    RepositoryItem = C.GIT_REPOSITORY_ITEM_WORKDIR
+	RepositoryItemCommonDir  RepositoryItem = C.GIT_REPOSITORY_ITEM_COMMONDIR
+	RepositoryItemIndex      RepositoryItem = C.GIT_REPOSITORY_ITEM_INDEX
+	RepositoryItemObjects    RepositoryItem = C.GIT_REPOSITORY_ITEM_OBJECTS
+	RepositoryItemRefs       RepositoryItem = C.GIT_REPOSITORY_ITEM_REFS
+	RepositoryItemPackedRefs RepositoryItem = C.GIT_REPOSITORY_ITEM_PACKED_REFS
+	RepositoryItemRemotes    RepositoryItem = C.GIT_REPOSITORY_ITEM_REMOTES
+	RepositoryItemConfig     RepositoryItem = C.GIT_REPOSITORY_ITEM_CONFIG
+	RepositoryItemInfo       RepositoryItem = C.GIT_REPOSITORY_ITEM_INFO
+	RepositoryItemHooks      RepositoryItem = C.GIT_REPOSITORY_ITEM_HOOKS
+	RepositoryItemLogs       RepositoryItem = C.GIT_REPOSITORY_ITEM_LOGS
+	RepositoryItemModules    RepositoryItem = C.GIT_REPOSITORY_ITEM_MODULES
+	RepositoryItemWorkTrees  RepositoryItem = C.GIT_REPOSITORY_ITEM_WORKTREES
+)
+
+func (r *Repository) ItemPath(item RepositoryItem) (string, error) {
+	var c_buf C.git_buf
+	defer C.git_buf_dispose(&c_buf)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_repository_item_path(&c_buf, r.ptr, C.git_repository_item_t(item))
+	runtime.KeepAlive(r)
+	if ret < 0 {
+		return "", MakeGitError(ret)
+	}
+	return C.GoString(c_buf.ptr), nil
 }

repository_test.go

@@ -0,0 +1,159 @@
+package git
+
+import (
+	"testing"
+	"time"
+)
+
+func TestCreateCommitBuffer(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	loc, err := time.LoadLocation("Europe/Berlin")
+	checkFatal(t, err)
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Date(2013, 03, 06, 14, 30, 0, 0, loc),
+	}
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+	err = idx.AddByPath("README")
+	checkFatal(t, err)
+	err = idx.Write()
+	checkFatal(t, err)
+	treeId, err := idx.WriteTree()
+	checkFatal(t, err)
+
+	message := "This is a commit\n"
+	tree, err := repo.LookupTree(treeId)
+	checkFatal(t, err)
+
+	for encoding, expected := range map[MessageEncoding]string{
+		MessageEncodingUTF8: `tree b7119b11e8ef7a1a5a34d3ac87f5b075228ac81e
+author Rand Om Hacker <random@hacker.com> 1362576600 +0100
+committer Rand Om Hacker <random@hacker.com> 1362576600 +0100
+
+This is a commit
+`,
+		MessageEncoding("ASCII"): `tree b7119b11e8ef7a1a5a34d3ac87f5b075228ac81e
+author Rand Om Hacker <random@hacker.com> 1362576600 +0100
+committer Rand Om Hacker <random@hacker.com> 1362576600 +0100
+encoding ASCII
+
+This is a commit
+`,
+	} {
+		encoding := encoding
+		expected := expected
+		t.Run(string(encoding), func(t *testing.T) {
+			buf, err := repo.CreateCommitBuffer(sig, sig, encoding, message, tree)
+			checkFatal(t, err)
+
+			if expected != string(buf) {
+				t.Errorf("mismatched commit buffer, expected %v, got %v", expected, string(buf))
+			}
+		})
+	}
+}
+
+func TestCreateCommitFromIds(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	loc, err := time.LoadLocation("Europe/Berlin")
+	checkFatal(t, err)
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Date(2013, 03, 06, 14, 30, 0, 0, loc),
+	}
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+	err = idx.AddByPath("README")
+	checkFatal(t, err)
+	err = idx.Write()
+	checkFatal(t, err)
+	treeId, err := idx.WriteTree()
+	checkFatal(t, err)
+
+	message := "This is a commit\n"
+	tree, err := repo.LookupTree(treeId)
+	checkFatal(t, err)
+	expectedCommitId, err := repo.CreateCommit("HEAD", sig, sig, message, tree)
+	checkFatal(t, err)
+
+	commitId, err := repo.CreateCommitFromIds("", sig, sig, message, treeId)
+	checkFatal(t, err)
+
+	if !expectedCommitId.Equal(commitId) {
+		t.Errorf("mismatched commit ids, expected %v, got %v", expectedCommitId.String(), commitId.String())
+	}
+}
+
+func TestRepositorySetConfig(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	loc, err := time.LoadLocation("Europe/Berlin")
+	checkFatal(t, err)
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Date(2013, 03, 06, 14, 30, 0, 0, loc),
+	}
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+	err = idx.AddByPath("README")
+
+	treeId, err := idx.WriteTree()
+	checkFatal(t, err)
+
+	message := "This is a commit\n"
+	tree, err := repo.LookupTree(treeId)
+	checkFatal(t, err)
+	_, err = repo.CreateCommit("HEAD", sig, sig, message, tree)
+	checkFatal(t, err)
+
+	repoConfig, err := repo.Config()
+	checkFatal(t, err)
+
+	temp := Config{}
+	localConfig, err := temp.OpenLevel(repoConfig, ConfigLevelLocal)
+	checkFatal(t, err)
+	repoConfig = nil
+
+	err = repo.SetConfig(localConfig)
+	checkFatal(t, err)
+
+	configFieldName := "core.filemode"
+	err = localConfig.SetBool(configFieldName, true)
+	checkFatal(t, err)
+
+	localConfig = nil
+
+	repoConfig, err = repo.Config()
+	checkFatal(t, err)
+
+	result, err := repoConfig.LookupBool(configFieldName)
+	checkFatal(t, err)
+	if result != true {
+		t.Fatal("result must be true")
+	}
+}
+
+func TestRepositoryItemPath(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	gitDir, err := repo.ItemPath(RepositoryItemGitDir)
+	checkFatal(t, err)
+	if gitDir == "" {
+		t.Error("expected not empty gitDir")
+	}
+}

reset.go

@@ -0,0 +1,49 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import "runtime"
+
+type ResetType int
+
+const (
+	ResetSoft  ResetType = C.GIT_RESET_SOFT
+	ResetMixed ResetType = C.GIT_RESET_MIXED
+	ResetHard  ResetType = C.GIT_RESET_HARD
+)
+
+func (r *Repository) ResetToCommit(commit *Commit, resetType ResetType, opts *CheckoutOptions) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var err error
+	cOpts := populateCheckoutOptions(&C.git_checkout_options{}, opts, &err)
+	defer freeCheckoutOptions(cOpts)
+
+	ret := C.git_reset(r.ptr, commit.ptr, C.git_reset_t(resetType), cOpts)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+func (r *Repository) ResetDefaultToCommit(commit *Commit, pathspecs []string) error {
+	cpathspecs := C.git_strarray{}
+	cpathspecs.count = C.size_t(len(pathspecs))
+	cpathspecs.strings = makeCStringsFromStrings(pathspecs)
+	defer freeStrarray(&cpathspecs)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+	ret := C.git_reset_default(r.ptr, commit.ptr, &cpathspecs)
+
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}

reset_test.go

@@ -0,0 +1,48 @@
+package git
+
+import (
+	"io/ioutil"
+	"testing"
+)
+
+func TestResetToCommit(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+	// create commit to reset to
+	commitId, _ := updateReadme(t, repo, "testing reset")
+	// create commit to reset from
+	nextCommitId, _ := updateReadme(t, repo, "will be reset")
+
+	// confirm that we wrote "will be reset" to the readme
+	newBytes, err := ioutil.ReadFile(pathInRepo(repo, "README"))
+	checkFatal(t, err)
+	if string(newBytes) != "will be reset" {
+		t.Fatalf("expected %s to equal 'will be reset'", string(newBytes))
+	}
+
+	// confirm that the head of the repo is the next commit id
+	head, err := repo.Head()
+	checkFatal(t, err)
+	if head.Target().String() != nextCommitId.String() {
+		t.Fatalf(
+			"expected to be at latest commit %s, but was %s",
+			nextCommitId.String(),
+			head.Target().String(),
+		)
+	}
+
+	commitToResetTo, err := repo.LookupCommit(commitId)
+	checkFatal(t, err)
+
+	repo.ResetToCommit(commitToResetTo, ResetHard, &CheckoutOptions{})
+
+	// check that the file now reads "testing reset" like it did before
+	bytes, err := ioutil.ReadFile(pathInRepo(repo, "README"))
+	checkFatal(t, err)
+	if string(bytes) != "testing reset" {
+		t.Fatalf("expected %s to equal 'testing reset'", string(bytes))
+	}
+}

revert.go

@@ -0,0 +1,104 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+)
+
+// RevertOptions contains options for performing a revert
+type RevertOptions struct {
+	Mainline        uint
+	MergeOptions    MergeOptions
+	CheckoutOptions CheckoutOptions
+}
+
+func populateRevertOptions(copts *C.git_revert_options, opts *RevertOptions, errorTarget *error) *C.git_revert_options {
+	C.git_revert_options_init(copts, C.GIT_REVERT_OPTIONS_VERSION)
+	if opts == nil {
+		return nil
+	}
+	copts.mainline = C.uint(opts.Mainline)
+	populateMergeOptions(&copts.merge_opts, &opts.MergeOptions)
+	populateCheckoutOptions(&copts.checkout_opts, &opts.CheckoutOptions, errorTarget)
+	return copts
+}
+
+func revertOptionsFromC(copts *C.git_revert_options) RevertOptions {
+	return RevertOptions{
+		Mainline:        uint(copts.mainline),
+		MergeOptions:    mergeOptionsFromC(&copts.merge_opts),
+		CheckoutOptions: checkoutOptionsFromC(&copts.checkout_opts),
+	}
+}
+
+func freeRevertOptions(copts *C.git_revert_options) {
+	if copts != nil {
+		return
+	}
+	freeMergeOptions(&copts.merge_opts)
+	freeCheckoutOptions(&copts.checkout_opts)
+}
+
+// DefaultRevertOptions initialises a RevertOptions struct with default values
+func DefaultRevertOptions() (RevertOptions, error) {
+	copts := C.git_revert_options{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_revert_options_init(&copts, C.GIT_REVERT_OPTIONS_VERSION)
+	if ecode < 0 {
+		return RevertOptions{}, MakeGitError(ecode)
+	}
+
+	defer freeRevertOptions(&copts)
+	return revertOptionsFromC(&copts), nil
+}
+
+// Revert the provided commit leaving the index updated with the results of the revert
+func (r *Repository) Revert(commit *Commit, revertOptions *RevertOptions) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var err error
+	cOpts := populateRevertOptions(&C.git_revert_options{}, revertOptions, &err)
+	defer freeRevertOptions(cOpts)
+
+	ret := C.git_revert(r.ptr, commit.cast_ptr, cOpts)
+	runtime.KeepAlive(r)
+	runtime.KeepAlive(commit)
+
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+// RevertCommit reverts the provided commit against "ourCommit"
+// The returned index contains the result of the revert and should be freed
+func (r *Repository) RevertCommit(revertCommit *Commit, ourCommit *Commit, mainline uint, mergeOptions *MergeOptions) (*Index, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cOpts := populateMergeOptions(&C.git_merge_options{}, mergeOptions)
+	defer freeMergeOptions(cOpts)
+
+	var index *C.git_index
+
+	ecode := C.git_revert_commit(&index, r.ptr, revertCommit.cast_ptr, ourCommit.cast_ptr, C.uint(mainline), cOpts)
+	runtime.KeepAlive(revertCommit)
+	runtime.KeepAlive(ourCommit)
+
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newIndexFromC(index, r), nil
+}

revert_test.go

@@ -0,0 +1,76 @@
+package git
+
+import (
+	"testing"
+)
+
+const (
+	expectedRevertedReadmeContents = "foo\n"
+)
+
+func TestRevert(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+	commitID, _ := updateReadme(t, repo, content)
+
+	commit, err := repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	revertOptions, err := DefaultRevertOptions()
+	checkFatal(t, err)
+
+	err = repo.Revert(commit, &revertOptions)
+	checkFatal(t, err)
+
+	actualReadmeContents := readReadme(t, repo)
+
+	if actualReadmeContents != expectedRevertedReadmeContents {
+		t.Fatalf(`README has incorrect contents after revert. Expected: "%v", Actual: "%v"`,
+			expectedRevertedReadmeContents, actualReadmeContents)
+	}
+
+	state := repo.State()
+	if state != RepositoryStateRevert {
+		t.Fatalf("Incorrect repository state. Expected: %v, Actual: %v", RepositoryStateRevert, state)
+	}
+
+	err = repo.StateCleanup()
+	checkFatal(t, err)
+
+	state = repo.State()
+	if state != RepositoryStateNone {
+		t.Fatalf("Incorrect repository state. Expected: %v, Actual: %v", RepositoryStateNone, state)
+	}
+}
+
+func TestRevertCommit(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+	commitID, _ := updateReadme(t, repo, content)
+
+	commit, err := repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	revertOptions, err := DefaultRevertOptions()
+	checkFatal(t, err)
+
+	index, err := repo.RevertCommit(commit, commit, 0, &revertOptions.MergeOptions)
+	checkFatal(t, err)
+	defer index.Free()
+
+	err = repo.CheckoutIndex(index, &revertOptions.CheckoutOptions)
+	checkFatal(t, err)
+
+	actualReadmeContents := readReadme(t, repo)
+
+	if actualReadmeContents != expectedRevertedReadmeContents {
+		t.Fatalf(`README has incorrect contents after revert. Expected: "%v", Actual: "%v"`,
+			expectedRevertedReadmeContents, actualReadmeContents)
+	}
+}

revparse.go

@@ -0,0 +1,114 @@
+package git
+
+/*
+#include <git2.h>
+
+extern void _go_git_revspec_free(git_revspec *revspec);
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+type RevparseFlag int
+
+const (
+	RevparseSingle    RevparseFlag = C.GIT_REVPARSE_SINGLE
+	RevparseRange     RevparseFlag = C.GIT_REVPARSE_RANGE
+	RevparseMergeBase RevparseFlag = C.GIT_REVPARSE_MERGE_BASE
+)
+
+type Revspec struct {
+	doNotCompare
+	to    *Object
+	from  *Object
+	flags RevparseFlag
+}
+
+func (rs *Revspec) To() *Object {
+	return rs.to
+}
+
+func (rs *Revspec) From() *Object {
+	return rs.from
+}
+
+func (rs *Revspec) Flags() RevparseFlag {
+	return rs.flags
+}
+
+func newRevspecFromC(ptr *C.git_revspec, repo *Repository) *Revspec {
+	var to *Object
+	var from *Object
+
+	if ptr.to != nil {
+		to = allocObject(ptr.to, repo)
+	}
+
+	if ptr.from != nil {
+		from = allocObject(ptr.from, repo)
+	}
+
+	return &Revspec{
+		to:    to,
+		from:  from,
+		flags: RevparseFlag(ptr.flags),
+	}
+}
+
+func (r *Repository) Revparse(spec string) (*Revspec, error) {
+	cspec := C.CString(spec)
+	defer C.free(unsafe.Pointer(cspec))
+
+	var crevspec C.git_revspec
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_revparse(&crevspec, r.ptr, cspec)
+	if ecode != 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return newRevspecFromC(&crevspec, r), nil
+}
+
+func (v *Repository) RevparseSingle(spec string) (*Object, error) {
+	cspec := C.CString(spec)
+	defer C.free(unsafe.Pointer(cspec))
+
+	var ptr *C.git_object
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_revparse_single(&ptr, v.ptr, cspec)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	return allocObject(ptr, v), nil
+}
+
+func (r *Repository) RevparseExt(spec string) (*Object, *Reference, error) {
+	cspec := C.CString(spec)
+	defer C.free(unsafe.Pointer(cspec))
+
+	var obj *C.git_object
+	var ref *C.git_reference
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_revparse_ext(&obj, &ref, r.ptr, cspec)
+	if ecode != 0 {
+		return nil, nil, MakeGitError(ecode)
+	}
+
+	if ref == nil {
+		return allocObject(obj, r), nil, nil
+	}
+
+	return allocObject(obj, r), newReferenceFromC(ref, r), nil
+}

revparse_test.go

@@ -0,0 +1,60 @@
+package git
+
+import (
+	"testing"
+)
+
+func TestRevparse(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId, _ := seedTestRepo(t, repo)
+
+	revSpec, err := repo.Revparse("HEAD")
+	checkFatal(t, err)
+
+	checkObject(t, revSpec.From(), commitId)
+}
+
+func TestRevparseSingle(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId, _ := seedTestRepo(t, repo)
+
+	obj, err := repo.RevparseSingle("HEAD")
+	checkFatal(t, err)
+
+	checkObject(t, obj, commitId)
+}
+
+func TestRevparseExt(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, treeId := seedTestRepo(t, repo)
+
+	ref, err := repo.References.Create("refs/heads/master", treeId, true, "")
+	checkFatal(t, err)
+
+	obj, ref, err := repo.RevparseExt("master")
+	checkFatal(t, err)
+
+	checkObject(t, obj, treeId)
+	if ref == nil {
+		t.Fatalf("bad reference")
+	}
+}
+
+func checkObject(t *testing.T, obj *Object, id *Oid) {
+	if obj == nil {
+		t.Fatalf("bad object")
+	}
+
+	if !obj.Id().Equal(id) {
+		t.Fatalf("bad object, expected %s, got %s", id.String(), obj.Id().String())
+	}
+}

script/build-libgit2-dynamic.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+set -e
+
+exec "$(dirname "$0")/build-libgit2.sh" --dynamic

script/build-libgit2-static.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+set -e
+
+exec "$(dirname "$0")/build-libgit2.sh" --static

script/build-libgit2.sh

@@ -0,0 +1,90 @@
+#!/bin/sh
+
+# Since CMake cannot build the static and dynamic libraries in the same
+# directory, this script helps build both static and dynamic versions of it and
+# have the common flags in one place instead of split between two places.
+
+set -e
+
+usage() {
+	echo "Usage: $0 <--dynamic|--static> [--system]">&2
+	exit 1
+}
+
+if [ "$#" -eq "0" ]; then
+	usage
+fi
+
+ROOT=${ROOT-"$(cd "$(dirname "$0")/.." && echo "${PWD}")"}
+VENDORED_PATH=${VENDORED_PATH-"${ROOT}/vendor/libgit2"}
+BUILD_SYSTEM=OFF
+
+while [ $# -gt 0 ]; do
+	case "$1" in
+		--static)
+			BUILD_PATH="${ROOT}/static-build"
+			BUILD_SHARED_LIBS=OFF
+			;;
+
+		--dynamic)
+			BUILD_PATH="${ROOT}/dynamic-build"
+			BUILD_SHARED_LIBS=ON
+			;;
+
+		--system)
+			BUILD_SYSTEM=ON
+			;;
+
+		*)
+			usage
+			;;
+	esac
+	shift
+done
+
+if [ -z "${BUILD_SHARED_LIBS}" ]; then
+	usage
+fi
+
+if [ -n "${BUILD_LIBGIT_REF}" ]; then
+	git -C "${VENDORED_PATH}" checkout "${BUILD_LIBGIT_REF}"
+	trap "git submodule update --init" EXIT
+fi
+
+BUILD_DEPRECATED_HARD="ON"
+if [ "${BUILD_SYSTEM}" = "ON" ]; then
+	BUILD_INSTALL_PREFIX=${SYSTEM_INSTALL_PREFIX-"/usr"}
+	# Most system-wide installations won't intentionally omit deprecated symbols.
+	BUILD_DEPRECATED_HARD="OFF"
+else
+	BUILD_INSTALL_PREFIX="${BUILD_PATH}/install"
+	mkdir -p "${BUILD_PATH}/install/lib"
+fi
+
+USE_BUNDLED_ZLIB="ON"
+if [ "${USE_CHROMIUM_ZLIB}" = "ON" ]; then
+	USE_BUNDLED_ZLIB="Chromium"
+fi
+
+mkdir -p "${BUILD_PATH}/build" &&
+cd "${BUILD_PATH}/build" &&
+cmake -DTHREADSAFE=ON \
+      -DBUILD_CLAR=OFF \
+      -DBUILD_SHARED_LIBS"=${BUILD_SHARED_LIBS}" \
+      -DREGEX_BACKEND=builtin \
+      -DUSE_BUNDLED_ZLIB="${USE_BUNDLED_ZLIB}" \
+      -DUSE_HTTPS=OFF \
+      -DUSE_SSH=OFF \
+      -DCMAKE_C_FLAGS=-fPIC \
+      -DCMAKE_BUILD_TYPE="RelWithDebInfo" \
+      -DCMAKE_INSTALL_PREFIX="${BUILD_INSTALL_PREFIX}" \
+      -DCMAKE_INSTALL_LIBDIR="lib" \
+      -DDEPRECATE_HARD="${BUILD_DEPRECATE_HARD}" \
+      "${VENDORED_PATH}"
+
+if which make nproc >/dev/null && [ -f Makefile ]; then
+	# Make the build parallel if make is available and cmake used Makefiles.
+	exec make "-j$(nproc --all)" install
+else
+	exec cmake --build . --target install
+fi

script/check-MakeGitError-thread-lock.go

@@ -0,0 +1,73 @@
+// +build ignore
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"go/ast"
+	"go/build"
+	"go/parser"
+	"go/printer"
+	"go/token"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var (
+	fset = token.NewFileSet()
+)
+
+func main() {
+	log.SetFlags(0)
+
+	bpkg, err := build.ImportDir(".", 0)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	pkgs, err := parser.ParseDir(fset, bpkg.Dir, func(fi os.FileInfo) bool { return filepath.Ext(fi.Name()) == ".go" }, 0)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for _, pkg := range pkgs {
+		if err := checkPkg(pkg); err != nil {
+			log.Fatal(err)
+		}
+	}
+	if len(pkgs) == 0 {
+		log.Fatal("No packages to check.")
+	}
+}
+
+var ignoreViolationsInFunc = map[string]bool{
+	"MakeGitError":  true,
+	"MakeGitError2": true,
+}
+
+func checkPkg(pkg *ast.Package) error {
+	var violations []string
+	ast.Inspect(pkg, func(node ast.Node) bool {
+		switch node := node.(type) {
+		case *ast.FuncDecl:
+			var b bytes.Buffer
+			if err := printer.Fprint(&b, fset, node); err != nil {
+				log.Fatal(err)
+			}
+			src := b.String()
+
+			if strings.Contains(src, "MakeGitError") && !strings.Contains(src, "runtime.LockOSThread()") && !strings.Contains(src, "defer runtime.UnlockOSThread()") && !ignoreViolationsInFunc[node.Name.Name] {
+				pos := fset.Position(node.Pos())
+				violations = append(violations, fmt.Sprintf("%s at %s:%d", node.Name.Name, pos.Filename, pos.Line))
+			}
+		}
+		return true
+	})
+	if len(violations) > 0 {
+		return fmt.Errorf("%d non-thread-locked calls to MakeGitError found. To fix, add the following to each func below that calls MakeGitError, before the cgo call that might produce the error:\n\n\truntime.LockOSThread()\n\tdefer runtime.UnlockOSThread()\n\n%s", len(violations), strings.Join(violations, "\n"))
+	}
+	return nil
+}

script/install-libgit2.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+
+#
+# Install libgit2 to go libgit2 in dynamic mode on Travis
+#
+
+set -ex
+
+# We don't want to build libgit2 on the next branch, as we carry a
+# submodule with the exact version we support
+if [ "x$TRAVIS_BRANCH" = "xnext" ]; then
+    exit 0
+fi
+
+cd "${HOME}"
+LG2VER="0.24.0"
+wget -O libgit2-${LG2VER}.tar.gz https://github.com/libgit2/libgit2/archive/v${LG2VER}.tar.gz
+tar -xzvf libgit2-${LG2VER}.tar.gz
+cd libgit2-${LG2VER} && mkdir build && cd build
+cmake -DTHREADSAFE=ON -DBUILD_CLAR=OFF -DCMAKE_BUILD_TYPE="RelWithDebInfo" .. && make && sudo make install
+sudo ldconfig
+cd "${TRAVIS_BUILD_DIR}"

settings.go

@@ -0,0 +1,174 @@
+package git
+
+/*
+#include <git2.h>
+
+int _go_git_opts_get_search_path(int level, git_buf *buf)
+{
+    return git_libgit2_opts(GIT_OPT_GET_SEARCH_PATH, level, buf);
+}
+
+int _go_git_opts_set_search_path(int level, const char *path)
+{
+    return git_libgit2_opts(GIT_OPT_SET_SEARCH_PATH, level, path);
+}
+
+int _go_git_opts_set_size_t(int opt, size_t val)
+{
+    return git_libgit2_opts(opt, val);
+}
+
+int _go_git_opts_set_cache_object_limit(git_object_t type, size_t size)
+{
+    return git_libgit2_opts(GIT_OPT_SET_CACHE_OBJECT_LIMIT, type, size);
+}
+
+int _go_git_opts_get_size_t(int opt, size_t *val)
+{
+    return git_libgit2_opts(opt, val);
+}
+
+int _go_git_opts_get_size_t_size_t(int opt, size_t *val1, size_t *val2)
+{
+    return git_libgit2_opts(opt, val1, val2);
+}
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+func SearchPath(level ConfigLevel) (string, error) {
+	var buf C.git_buf
+	defer C.git_buf_dispose(&buf)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C._go_git_opts_get_search_path(C.int(level), &buf)
+	if err < 0 {
+		return "", MakeGitError(err)
+	}
+
+	return C.GoString(buf.ptr), nil
+}
+
+func SetSearchPath(level ConfigLevel, path string) error {
+	cpath := C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C._go_git_opts_set_search_path(C.int(level), cpath)
+	if err < 0 {
+		return MakeGitError(err)
+	}
+
+	return nil
+}
+
+func MwindowSize() (int, error) {
+	return getSizet(C.GIT_OPT_GET_MWINDOW_SIZE)
+}
+
+func SetMwindowSize(size int) error {
+	return setSizet(C.GIT_OPT_SET_MWINDOW_SIZE, size)
+}
+
+func MwindowMappedLimit() (int, error) {
+	return getSizet(C.GIT_OPT_GET_MWINDOW_MAPPED_LIMIT)
+}
+
+func SetMwindowMappedLimit(size int) error {
+	return setSizet(C.GIT_OPT_SET_MWINDOW_MAPPED_LIMIT, size)
+}
+
+func EnableCaching(enabled bool) error {
+	if enabled {
+		return setSizet(C.GIT_OPT_ENABLE_CACHING, 1)
+	} else {
+		return setSizet(C.GIT_OPT_ENABLE_CACHING, 0)
+	}
+}
+
+func EnableStrictHashVerification(enabled bool) error {
+	if enabled {
+		return setSizet(C.GIT_OPT_ENABLE_STRICT_HASH_VERIFICATION, 1)
+	} else {
+		return setSizet(C.GIT_OPT_ENABLE_STRICT_HASH_VERIFICATION, 0)
+	}
+}
+
+func EnableFsyncGitDir(enabled bool) error {
+	if enabled {
+		return setSizet(C.GIT_OPT_ENABLE_FSYNC_GITDIR, 1)
+	} else {
+		return setSizet(C.GIT_OPT_ENABLE_FSYNC_GITDIR, 0)
+	}
+}
+
+func CachedMemory() (current int, allowed int, err error) {
+	return getSizetSizet(C.GIT_OPT_GET_CACHED_MEMORY)
+}
+
+// deprecated: You should use `CachedMemory()` instead.
+func GetCachedMemory() (current int, allowed int, err error) {
+	return CachedMemory()
+}
+
+func SetCacheMaxSize(maxSize int) error {
+	return setSizet(C.GIT_OPT_SET_CACHE_MAX_SIZE, maxSize)
+}
+
+func SetCacheObjectLimit(objectType ObjectType, size int) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	err := C._go_git_opts_set_cache_object_limit(C.git_object_t(objectType), C.size_t(size))
+	if err < 0 {
+		return MakeGitError(err)
+	}
+
+	return nil
+}
+
+func getSizet(opt C.int) (int, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var val C.size_t
+	err := C._go_git_opts_get_size_t(opt, &val)
+	if err < 0 {
+		return 0, MakeGitError(err)
+	}
+
+	return int(val), nil
+}
+
+func getSizetSizet(opt C.int) (int, int, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var val1, val2 C.size_t
+	err := C._go_git_opts_get_size_t_size_t(opt, &val1, &val2)
+	if err < 0 {
+		return 0, 0, MakeGitError(err)
+	}
+
+	return int(val1), int(val2), nil
+}
+
+func setSizet(opt C.int, val int) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cval := C.size_t(val)
+	err := C._go_git_opts_set_size_t(opt, cval)
+	if err < 0 {
+		return MakeGitError(err)
+	}
+
+	return nil
+}

settings_test.go

@@ -0,0 +1,99 @@
+package git
+
+import (
+	"testing"
+)
+
+type pathPair struct {
+	Level ConfigLevel
+	Path  string
+}
+
+func TestSearchPath(t *testing.T) {
+	paths := []pathPair{
+		pathPair{ConfigLevelSystem, "/tmp/system"},
+		pathPair{ConfigLevelGlobal, "/tmp/global"},
+		pathPair{ConfigLevelXDG, "/tmp/xdg"},
+	}
+
+	for _, pair := range paths {
+		err := SetSearchPath(pair.Level, pair.Path)
+		checkFatal(t, err)
+
+		actual, err := SearchPath(pair.Level)
+		checkFatal(t, err)
+
+		if pair.Path != actual {
+			t.Fatal("Search paths don't match")
+		}
+	}
+}
+
+func TestMmapSizes(t *testing.T) {
+	size := 42 * 1024
+
+	err := SetMwindowSize(size)
+	checkFatal(t, err)
+
+	actual, err := MwindowSize()
+	if size != actual {
+		t.Fatal("Sizes don't match")
+	}
+
+	err = SetMwindowMappedLimit(size)
+	checkFatal(t, err)
+
+	actual, err = MwindowMappedLimit()
+	if size != actual {
+		t.Fatal("Sizes don't match")
+	}
+}
+
+func TestEnableCaching(t *testing.T) {
+	err := EnableCaching(false)
+	checkFatal(t, err)
+
+	err = EnableCaching(true)
+	checkFatal(t, err)
+}
+
+func TestEnableStrictHashVerification(t *testing.T) {
+	err := EnableStrictHashVerification(false)
+	checkFatal(t, err)
+
+	err = EnableStrictHashVerification(true)
+	checkFatal(t, err)
+}
+
+func TestEnableFsyncGitDir(t *testing.T) {
+	err := EnableFsyncGitDir(false)
+	checkFatal(t, err)
+
+	err = EnableFsyncGitDir(true)
+	checkFatal(t, err)
+}
+
+func TestCachedMemory(t *testing.T) {
+	current, allowed, err := CachedMemory()
+	checkFatal(t, err)
+
+	if current < 0 {
+		t.Fatal("current < 0")
+	}
+
+	if allowed < 0 {
+		t.Fatal("allowed < 0")
+	}
+}
+
+func TestSetCacheMaxSize(t *testing.T) {
+	err := SetCacheMaxSize(0)
+	checkFatal(t, err)
+
+	err = SetCacheMaxSize(1024 * 1024)
+	checkFatal(t, err)
+
+	// revert to default 256MB
+	err = SetCacheMaxSize(256 * 1024 * 1024)
+	checkFatal(t, err)
+}

signature.go

@@ -0,0 +1,78 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+import (
+	"runtime"
+	"time"
+	"unsafe"
+)
+
+type Signature struct {
+	Name  string
+	Email string
+	When  time.Time
+}
+
+func newSignatureFromC(sig *C.git_signature) *Signature {
+	if sig == nil {
+		return nil
+	}
+
+	// git stores minutes, go wants seconds
+	loc := time.FixedZone("", int(sig.when.offset)*60)
+	return &Signature{
+		C.GoString(sig.name),
+		C.GoString(sig.email),
+		time.Unix(int64(sig.when.time), 0).In(loc),
+	}
+}
+
+// Offset returns the time zone offset of v.When in minutes, which is what git wants.
+func (v *Signature) Offset() int {
+	_, offset := v.When.Zone()
+	return offset / 60
+}
+
+func (sig *Signature) toC() (*C.git_signature, error) {
+	if sig == nil {
+		return nil, nil
+	}
+
+	var out *C.git_signature
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	name := C.CString(sig.Name)
+	defer C.free(unsafe.Pointer(name))
+
+	email := C.CString(sig.Email)
+	defer C.free(unsafe.Pointer(email))
+
+	ret := C.git_signature_new(&out, name, email, C.git_time_t(sig.When.Unix()), C.int(sig.Offset()))
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return out, nil
+}
+
+func (repo *Repository) DefaultSignature() (*Signature, error) {
+	var out *C.git_signature
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cErr := C.git_signature_default(&out, repo.ptr)
+	runtime.KeepAlive(repo)
+	if cErr < 0 {
+		return nil, MakeGitError(cErr)
+	}
+
+	defer C.git_signature_free(out)
+
+	return newSignatureFromC(out), nil
+}

ssh.go

@@ -0,0 +1,250 @@
+package git
+
+/*
+#include <git2.h>
+
+#include <git2/sys/credential.h>
+*/
+import "C"
+import (
+	"crypto/md5"
+	"crypto/sha1"
+	"crypto/sha256"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"net/url"
+	"runtime"
+	"strings"
+	"unsafe"
+
+	"golang.org/x/crypto/ssh"
+)
+
+// RegisterManagedSSHTransport registers a Go-native implementation of an SSH
+// transport that doesn't rely on any system libraries (e.g. libssh2).
+//
+// If Shutdown or ReInit are called, make sure that the smart transports are
+// freed before it.
+func RegisterManagedSSHTransport(protocol string) (*RegisteredSmartTransport, error) {
+	return NewRegisteredSmartTransport(protocol, false, sshSmartSubtransportFactory)
+}
+
+func registerManagedSSH() error {
+	globalRegisteredSmartTransports.Lock()
+	defer globalRegisteredSmartTransports.Unlock()
+
+	for _, protocol := range []string{"ssh", "ssh+git", "git+ssh"} {
+		if _, ok := globalRegisteredSmartTransports.transports[protocol]; ok {
+			continue
+		}
+		managed, err := newRegisteredSmartTransport(protocol, false, sshSmartSubtransportFactory, true)
+		if err != nil {
+			return fmt.Errorf("failed to register transport for %q: %v", protocol, err)
+		}
+		globalRegisteredSmartTransports.transports[protocol] = managed
+	}
+	return nil
+}
+
+func sshSmartSubtransportFactory(remote *Remote, transport *Transport) (SmartSubtransport, error) {
+	return &sshSmartSubtransport{
+		transport: transport,
+	}, nil
+}
+
+type sshSmartSubtransport struct {
+	transport *Transport
+
+	lastAction    SmartServiceAction
+	client        *ssh.Client
+	session       *ssh.Session
+	stdin         io.WriteCloser
+	stdout        io.Reader
+	currentStream *sshSmartSubtransportStream
+}
+
+func (t *sshSmartSubtransport) Action(urlString string, action SmartServiceAction) (SmartSubtransportStream, error) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	u, err := url.Parse(urlString)
+	if err != nil {
+		return nil, err
+	}
+
+	// Escape \ and '.
+	uPath := strings.Replace(u.Path, `\`, `\\`, -1)
+	uPath = strings.Replace(uPath, `'`, `\'`, -1)
+
+	// TODO: Add percentage decode similar to libgit2.
+	// Refer: https://github.com/libgit2/libgit2/blob/358a60e1b46000ea99ef10b4dd709e92f75ff74b/src/str.c#L455-L481
+
+	var cmd string
+	switch action {
+	case SmartServiceActionUploadpackLs, SmartServiceActionUploadpack:
+		if t.currentStream != nil {
+			if t.lastAction == SmartServiceActionUploadpackLs {
+				return t.currentStream, nil
+			}
+			t.Close()
+		}
+		cmd = fmt.Sprintf("git-upload-pack '%s'", uPath)
+
+	case SmartServiceActionReceivepackLs, SmartServiceActionReceivepack:
+		if t.currentStream != nil {
+			if t.lastAction == SmartServiceActionReceivepackLs {
+				return t.currentStream, nil
+			}
+			t.Close()
+		}
+		cmd = fmt.Sprintf("git-receive-pack '%s'", uPath)
+
+	default:
+		return nil, fmt.Errorf("unexpected action: %v", action)
+	}
+
+	cred, err := t.transport.SmartCredentials("", CredentialTypeSSHKey|CredentialTypeSSHMemory)
+	if err != nil {
+		return nil, err
+	}
+	defer cred.Free()
+
+	sshConfig, err := getSSHConfigFromCredential(cred)
+	if err != nil {
+		return nil, err
+	}
+	sshConfig.HostKeyCallback = func(hostname string, remote net.Addr, key ssh.PublicKey) error {
+		marshaledKey := key.Marshal()
+		cert := &Certificate{
+			Kind: CertificateHostkey,
+			Hostkey: HostkeyCertificate{
+				Kind:         HostkeySHA1 | HostkeyMD5 | HostkeySHA256 | HostkeyRaw,
+				HashMD5:      md5.Sum(marshaledKey),
+				HashSHA1:     sha1.Sum(marshaledKey),
+				HashSHA256:   sha256.Sum256(marshaledKey),
+				Hostkey:      marshaledKey,
+				SSHPublicKey: key,
+			},
+		}
+
+		return t.transport.SmartCertificateCheck(cert, true, hostname)
+	}
+
+	var addr string
+	if u.Port() != "" {
+		addr = fmt.Sprintf("%s:%s", u.Hostname(), u.Port())
+	} else {
+		addr = fmt.Sprintf("%s:22", u.Hostname())
+	}
+
+	t.client, err = ssh.Dial("tcp", addr, sshConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	t.session, err = t.client.NewSession()
+	if err != nil {
+		return nil, err
+	}
+
+	t.stdin, err = t.session.StdinPipe()
+	if err != nil {
+		return nil, err
+	}
+
+	t.stdout, err = t.session.StdoutPipe()
+	if err != nil {
+		return nil, err
+	}
+
+	if err := t.session.Start(cmd); err != nil {
+		return nil, err
+	}
+
+	t.lastAction = action
+	t.currentStream = &sshSmartSubtransportStream{
+		owner: t,
+	}
+
+	return t.currentStream, nil
+}
+
+func (t *sshSmartSubtransport) Close() error {
+	t.currentStream = nil
+	if t.client != nil {
+		t.stdin.Close()
+		t.session.Wait()
+		t.session.Close()
+		t.client = nil
+	}
+	return nil
+}
+
+func (t *sshSmartSubtransport) Free() {
+}
+
+type sshSmartSubtransportStream struct {
+	owner *sshSmartSubtransport
+}
+
+func (stream *sshSmartSubtransportStream) Read(buf []byte) (int, error) {
+	return stream.owner.stdout.Read(buf)
+}
+
+func (stream *sshSmartSubtransportStream) Write(buf []byte) (int, error) {
+	return stream.owner.stdin.Write(buf)
+}
+
+func (stream *sshSmartSubtransportStream) Free() {
+}
+
+func getSSHConfigFromCredential(cred *Credential) (*ssh.ClientConfig, error) {
+	switch cred.Type() {
+	case CredentialTypeSSHCustom:
+		credSSHCustom := (*C.git_credential_ssh_custom)(unsafe.Pointer(cred.ptr))
+		data, ok := pointerHandles.Get(credSSHCustom.payload).(*credentialSSHCustomData)
+		if !ok {
+			return nil, errors.New("unsupported custom SSH credentials")
+		}
+		return &ssh.ClientConfig{
+			User: C.GoString(credSSHCustom.username),
+			Auth: []ssh.AuthMethod{ssh.PublicKeys(data.signer)},
+		}, nil
+	}
+
+	username, _, privatekey, passphrase, err := cred.GetSSHKey()
+	if err != nil {
+		return nil, err
+	}
+
+	var pemBytes []byte
+	if cred.Type() == CredentialTypeSSHMemory {
+		pemBytes = []byte(privatekey)
+	} else {
+		pemBytes, err = ioutil.ReadFile(privatekey)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	var key ssh.Signer
+	if passphrase != "" {
+		key, err = ssh.ParsePrivateKeyWithPassphrase(pemBytes, []byte(passphrase))
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		key, err = ssh.ParsePrivateKey(pemBytes)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return &ssh.ClientConfig{
+		User: username,
+		Auth: []ssh.AuthMethod{ssh.PublicKeys(key)},
+	}, nil
+}

stash.go

@@ -0,0 +1,337 @@
+package git
+
+/*
+#include <git2.h>
+
+extern void _go_git_populate_stash_apply_callbacks(git_stash_apply_options *opts);
+extern int _go_git_stash_foreach(git_repository *repo, void *payload);
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+// StashFlag are flags that affect the stash save operation.
+type StashFlag int
+
+const (
+	// StashDefault represents no option, default.
+	StashDefault StashFlag = C.GIT_STASH_DEFAULT
+
+	// StashKeepIndex leaves all changes already added to the
+	// index intact in the working directory.
+	StashKeepIndex StashFlag = C.GIT_STASH_KEEP_INDEX
+
+	// StashIncludeUntracked means all untracked files are also
+	// stashed and then cleaned up from the working directory.
+	StashIncludeUntracked StashFlag = C.GIT_STASH_INCLUDE_UNTRACKED
+
+	// StashIncludeIgnored means all ignored files are also
+	// stashed and then cleaned up from the working directory.
+	StashIncludeIgnored StashFlag = C.GIT_STASH_INCLUDE_IGNORED
+)
+
+// StashCollection represents the possible operations that can be
+// performed on the collection of stashes for a repository.
+type StashCollection struct {
+	doNotCompare
+	repo *Repository
+}
+
+// Save saves the local modifications to a new stash.
+//
+// Stasher is the identity of the person performing the stashing.
+// Message is the optional description along with the stashed state.
+// Flags control the stashing process and are given as bitwise OR.
+func (c *StashCollection) Save(
+	stasher *Signature, message string, flags StashFlag) (*Oid, error) {
+
+	oid := new(Oid)
+
+	stasherC, err := stasher.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(stasherC)
+
+	messageC := C.CString(message)
+	defer C.free(unsafe.Pointer(messageC))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_stash_save(
+		oid.toC(), c.repo.ptr,
+		stasherC, messageC, C.uint32_t(flags))
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+	return oid, nil
+}
+
+// StashApplyFlag are flags that affect the stash apply operation.
+type StashApplyFlag int
+
+const (
+	// StashApplyDefault is the default.
+	StashApplyDefault StashApplyFlag = C.GIT_STASH_APPLY_DEFAULT
+
+	// StashApplyReinstateIndex will try to reinstate not only the
+	// working tree's changes, but also the index's changes.
+	StashApplyReinstateIndex StashApplyFlag = C.GIT_STASH_APPLY_REINSTATE_INDEX
+)
+
+// StashApplyProgress are flags describing the progress of the apply operation.
+type StashApplyProgress int
+
+const (
+	// StashApplyProgressNone means loading the stashed data from the object store.
+	StashApplyProgressNone StashApplyProgress = C.GIT_STASH_APPLY_PROGRESS_NONE
+
+	// StashApplyProgressLoadingStash means the stored index is being analyzed.
+	StashApplyProgressLoadingStash StashApplyProgress = C.GIT_STASH_APPLY_PROGRESS_LOADING_STASH
+
+	// StashApplyProgressAnalyzeIndex means the stored index is being analyzed.
+	StashApplyProgressAnalyzeIndex StashApplyProgress = C.GIT_STASH_APPLY_PROGRESS_ANALYZE_INDEX
+
+	// StashApplyProgressAnalyzeModified means the modified files are being analyzed.
+	StashApplyProgressAnalyzeModified StashApplyProgress = C.GIT_STASH_APPLY_PROGRESS_ANALYZE_MODIFIED
+
+	// StashApplyProgressAnalyzeUntracked means the untracked and ignored files are being analyzed.
+	StashApplyProgressAnalyzeUntracked StashApplyProgress = C.GIT_STASH_APPLY_PROGRESS_ANALYZE_UNTRACKED
+
+	// StashApplyProgressCheckoutUntracked means the untracked files are being written to disk.
+	StashApplyProgressCheckoutUntracked StashApplyProgress = C.GIT_STASH_APPLY_PROGRESS_CHECKOUT_UNTRACKED
+
+	// StashApplyProgressCheckoutModified means the modified files are being written to disk.
+	StashApplyProgressCheckoutModified StashApplyProgress = C.GIT_STASH_APPLY_PROGRESS_CHECKOUT_MODIFIED
+
+	// StashApplyProgressDone means the stash was applied successfully.
+	StashApplyProgressDone StashApplyProgress = C.GIT_STASH_APPLY_PROGRESS_DONE
+)
+
+// StashApplyProgressCallback is the apply operation notification callback.
+type StashApplyProgressCallback func(progress StashApplyProgress) error
+type stashApplyProgressCallbackData struct {
+	callback    StashApplyProgressCallback
+	errorTarget *error
+}
+
+//export stashApplyProgressCallback
+func stashApplyProgressCallback(progress C.git_stash_apply_progress_t, handle unsafe.Pointer) C.int {
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*stashApplyProgressCallbackData)
+	if !ok {
+		panic("could not retrieve data for handle")
+	}
+	if data == nil || data.callback == nil {
+		return C.int(ErrorCodeOK)
+	}
+
+	err := data.callback(StashApplyProgress(progress))
+	if err != nil {
+		*data.errorTarget = err
+		return C.int(ErrorCodeUser)
+	}
+	return C.int(ErrorCodeOK)
+}
+
+// StashApplyOptions represents options to control the apply operation.
+type StashApplyOptions struct {
+	Flags            StashApplyFlag
+	CheckoutOptions  CheckoutOptions            // options to use when writing files to the working directory
+	ProgressCallback StashApplyProgressCallback // optional callback to notify the consumer of application progress
+}
+
+// DefaultStashApplyOptions initializes the structure with default values.
+func DefaultStashApplyOptions() (StashApplyOptions, error) {
+	optsC := C.git_stash_apply_options{}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_stash_apply_options_init(&optsC, C.GIT_STASH_APPLY_OPTIONS_VERSION)
+	if ecode < 0 {
+		return StashApplyOptions{}, MakeGitError(ecode)
+	}
+	return StashApplyOptions{
+		Flags:           StashApplyFlag(optsC.flags),
+		CheckoutOptions: checkoutOptionsFromC(&optsC.checkout_options),
+	}, nil
+}
+
+func populateStashApplyOptions(copts *C.git_stash_apply_options, opts *StashApplyOptions, errorTarget *error) *C.git_stash_apply_options {
+	C.git_stash_apply_options_init(copts, C.GIT_STASH_APPLY_OPTIONS_VERSION)
+	if opts == nil {
+		return nil
+	}
+	copts.flags = C.uint32_t(opts.Flags)
+	populateCheckoutOptions(&copts.checkout_options, &opts.CheckoutOptions, errorTarget)
+	if opts.ProgressCallback != nil {
+		progressData := &stashApplyProgressCallbackData{
+			callback:    opts.ProgressCallback,
+			errorTarget: errorTarget,
+		}
+		C._go_git_populate_stash_apply_callbacks(copts)
+		copts.progress_payload = pointerHandles.Track(progressData)
+	}
+	return copts
+}
+
+func freeStashApplyOptions(copts *C.git_stash_apply_options) {
+	if copts == nil {
+		return
+	}
+	if copts.progress_payload != nil {
+		pointerHandles.Untrack(copts.progress_payload)
+	}
+	freeCheckoutOptions(&copts.checkout_options)
+}
+
+// Apply applies a single stashed state from the stash list.
+//
+// If local changes in the working directory conflict with changes in the
+// stash then ErrorCodeConflict will be returned.  In this case, the index
+// will always remain unmodified and all files in the working directory will
+// remain unmodified.  However, if you are restoring untracked files or
+// ignored files and there is a conflict when applying the modified files,
+// then those files will remain in the working directory.
+//
+// If passing the StashApplyReinstateIndex flag and there would be conflicts
+// when reinstating the index, the function will return ErrorCodeConflict
+// and both the working directory and index will be left unmodified.
+//
+// Note that a minimum checkout strategy of 'CheckoutSafe' is implied.
+//
+// 'index' is the position within the stash list. 0 points to the most
+// recent stashed state.
+//
+// Returns error code ErrorCodeNotFound if there's no stashed state for the given
+// index, error code ErrorCodeConflict if local changes in the working directory
+// conflict with changes in the stash, the user returned error from the
+// StashApplyProgressCallback, if any, or other error code.
+//
+// Error codes can be interogated with IsErrorCode(err, ErrorCodeNotFound).
+func (c *StashCollection) Apply(index int, opts StashApplyOptions) error {
+	var err error
+	optsC := populateStashApplyOptions(&C.git_stash_apply_options{}, &opts, &err)
+	defer freeStashApplyOptions(optsC)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_stash_apply(c.repo.ptr, C.size_t(index), optsC)
+	runtime.KeepAlive(c)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+// StashCallback is called per entry when interating over all
+// the stashed states.
+//
+// 'index' is the position of the current stash in the stash list,
+// 'message' is the message used when creating the stash and 'id'
+// is the commit id of the stash.
+type StashCallback func(index int, message string, id *Oid) error
+type stashCallbackData struct {
+	callback    StashCallback
+	errorTarget *error
+}
+
+//export stashForeachCallback
+func stashForeachCallback(index C.size_t, message *C.char, id *C.git_oid, handle unsafe.Pointer) C.int {
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*stashCallbackData)
+	if !ok {
+		panic("could not retrieve data for handle")
+	}
+
+	err := data.callback(int(index), C.GoString(message), newOidFromC(id))
+	if err != nil {
+		*data.errorTarget = err
+		return C.int(ErrorCodeUser)
+	}
+	return C.int(ErrorCodeOK)
+}
+
+// Foreach loops over all the stashed states and calls the callback
+// for each one.
+//
+// If callback returns an error, this will stop looping.
+func (c *StashCollection) Foreach(callback StashCallback) error {
+	var err error
+	data := stashCallbackData{
+		callback:    callback,
+		errorTarget: &err,
+	}
+	handle := pointerHandles.Track(&data)
+	defer pointerHandles.Untrack(handle)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C._go_git_stash_foreach(c.repo.ptr, handle)
+	runtime.KeepAlive(c)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+// Drop removes a single stashed state from the stash list.
+//
+// 'index' is the position within the stash list. 0 points
+// to the most recent stashed state.
+//
+// Returns error code ErrorCodeNotFound if there's no stashed
+// state for the given index.
+func (c *StashCollection) Drop(index int) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_stash_drop(c.repo.ptr, C.size_t(index))
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}
+
+// Pop applies a single stashed state from the stash list
+// and removes it from the list if successful.
+//
+// 'index' is the position within the stash list. 0 points
+// to the most recent stashed state.
+//
+// 'opts' controls how stashes are applied.
+//
+// Returns error code ErrorCodeNotFound if there's no stashed
+// state for the given index.
+func (c *StashCollection) Pop(index int, opts StashApplyOptions) error {
+	var err error
+	optsC := populateStashApplyOptions(&C.git_stash_apply_options{}, &opts, &err)
+	defer freeStashApplyOptions(optsC)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_stash_pop(c.repo.ptr, C.size_t(index), optsC)
+	runtime.KeepAlive(c)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+	return nil
+}

stash_test.go

@@ -0,0 +1,198 @@
+package git
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"reflect"
+	"runtime"
+	"testing"
+	"time"
+)
+
+func TestStash(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	prepareStashRepo(t, repo)
+
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Now(),
+	}
+
+	stash1, err := repo.Stashes.Save(sig, "First stash", StashDefault)
+	checkFatal(t, err)
+
+	_, err = repo.LookupCommit(stash1)
+	checkFatal(t, err)
+
+	b, err := ioutil.ReadFile(pathInRepo(repo, "README"))
+	checkFatal(t, err)
+	if string(b) == "Update README goes to stash\n" {
+		t.Errorf("README still contains the uncommitted changes")
+	}
+
+	if !fileExistsInRepo(repo, "untracked.txt") {
+		t.Errorf("untracked.txt doesn't exist in the repo; should be untracked")
+	}
+
+	// Apply: default
+
+	opts, err := DefaultStashApplyOptions()
+	checkFatal(t, err)
+
+	err = repo.Stashes.Apply(0, opts)
+	checkFatal(t, err)
+
+	b, err = ioutil.ReadFile(pathInRepo(repo, "README"))
+	checkFatal(t, err)
+	if string(b) != "Update README goes to stash\n" {
+		t.Errorf("README changes aren't here")
+	}
+
+	// Apply: no stash for the given index
+
+	err = repo.Stashes.Apply(1, opts)
+	if !IsErrorCode(err, ErrorCodeNotFound) {
+		t.Errorf("expecting GIT_ENOTFOUND error code %d, got %v", ErrorCodeNotFound, err)
+	}
+
+	// Apply: callback stopped
+
+	opts.ProgressCallback = func(progress StashApplyProgress) error {
+		if progress == StashApplyProgressCheckoutModified {
+			return fmt.Errorf("Stop")
+		}
+		return nil
+	}
+
+	err = repo.Stashes.Apply(0, opts)
+	if err.Error() != "Stop" {
+		t.Errorf("expecting error 'Stop', got %v", err)
+	}
+
+	// Create second stash with ignored files
+
+	os.MkdirAll(pathInRepo(repo, "tmp"), os.ModeDir|os.ModePerm)
+	err = ioutil.WriteFile(pathInRepo(repo, "tmp/ignored.txt"), []byte("Ignore me\n"), 0644)
+	checkFatal(t, err)
+
+	stash2, err := repo.Stashes.Save(sig, "Second stash", StashIncludeIgnored)
+	checkFatal(t, err)
+
+	if fileExistsInRepo(repo, "tmp/ignored.txt") {
+		t.Errorf("tmp/ignored.txt should not exist anymore in the work dir")
+	}
+
+	// Stash foreach
+
+	expected := []stash{
+		{0, "On master: Second stash", stash2.String()},
+		{1, "On master: First stash", stash1.String()},
+	}
+	checkStashes(t, repo, expected)
+
+	// Stash pop
+
+	opts, _ = DefaultStashApplyOptions()
+	err = repo.Stashes.Pop(1, opts)
+	checkFatal(t, err)
+
+	b, err = ioutil.ReadFile(pathInRepo(repo, "README"))
+	checkFatal(t, err)
+	if string(b) != "Update README goes to stash\n" {
+		t.Errorf("README changes aren't here")
+	}
+
+	expected = []stash{
+		{0, "On master: Second stash", stash2.String()},
+	}
+	checkStashes(t, repo, expected)
+
+	// Stash drop
+
+	err = repo.Stashes.Drop(0)
+	checkFatal(t, err)
+
+	expected = []stash{}
+	checkStashes(t, repo, expected)
+}
+
+type stash struct {
+	index int
+	msg   string
+	id    string
+}
+
+func checkStashes(t *testing.T, repo *Repository, expected []stash) {
+	var actual []stash
+
+	repo.Stashes.Foreach(func(index int, msg string, id *Oid) error {
+		stash := stash{index, msg, id.String()}
+		if len(expected) > len(actual) {
+			if s := expected[len(actual)]; s.id == "" {
+				stash.id = "" //  don't check id
+			}
+		}
+		actual = append(actual, stash)
+		return nil
+	})
+
+	if len(expected) > 0 && !reflect.DeepEqual(expected, actual) {
+		// The failure happens at wherever we were called, not here
+		_, file, line, ok := runtime.Caller(1)
+		if !ok {
+			t.Fatalf("Unable to get caller")
+		}
+		t.Errorf("%v:%v: expecting %#v\ngot %#v", path.Base(file), line, expected, actual)
+	}
+}
+
+func prepareStashRepo(t *testing.T, repo *Repository) {
+	seedTestRepo(t, repo)
+
+	err := ioutil.WriteFile(pathInRepo(repo, ".gitignore"), []byte("tmp\n"), 0644)
+	checkFatal(t, err)
+
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Now(),
+	}
+
+	idx, err := repo.Index()
+	checkFatal(t, err)
+	err = idx.AddByPath(".gitignore")
+	checkFatal(t, err)
+	treeID, err := idx.WriteTree()
+	checkFatal(t, err)
+	err = idx.Write()
+	checkFatal(t, err)
+
+	currentBranch, err := repo.Head()
+	checkFatal(t, err)
+	currentTip, err := repo.LookupCommit(currentBranch.Target())
+	checkFatal(t, err)
+
+	message := "Add .gitignore\n"
+	tree, err := repo.LookupTree(treeID)
+	checkFatal(t, err)
+	_, err = repo.CreateCommit("HEAD", sig, sig, message, tree, currentTip)
+	checkFatal(t, err)
+
+	err = ioutil.WriteFile(pathInRepo(repo, "README"), []byte("Update README goes to stash\n"), 0644)
+	checkFatal(t, err)
+
+	err = ioutil.WriteFile(pathInRepo(repo, "untracked.txt"), []byte("Hello, World\n"), 0644)
+	checkFatal(t, err)
+}
+
+func fileExistsInRepo(repo *Repository, name string) bool {
+	if _, err := os.Stat(pathInRepo(repo, name)); err != nil {
+		return false
+	}
+	return true
+}

status.go

@@ -0,0 +1,194 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+
+import (
+	"errors"
+	"runtime"
+	"unsafe"
+)
+
+type Status int
+
+const (
+	StatusCurrent         Status = C.GIT_STATUS_CURRENT
+	StatusIndexNew        Status = C.GIT_STATUS_INDEX_NEW
+	StatusIndexModified   Status = C.GIT_STATUS_INDEX_MODIFIED
+	StatusIndexDeleted    Status = C.GIT_STATUS_INDEX_DELETED
+	StatusIndexRenamed    Status = C.GIT_STATUS_INDEX_RENAMED
+	StatusIndexTypeChange Status = C.GIT_STATUS_INDEX_TYPECHANGE
+	StatusWtNew           Status = C.GIT_STATUS_WT_NEW
+	StatusWtModified      Status = C.GIT_STATUS_WT_MODIFIED
+	StatusWtDeleted       Status = C.GIT_STATUS_WT_DELETED
+	StatusWtTypeChange    Status = C.GIT_STATUS_WT_TYPECHANGE
+	StatusWtRenamed       Status = C.GIT_STATUS_WT_RENAMED
+	StatusIgnored         Status = C.GIT_STATUS_IGNORED
+	StatusConflicted      Status = C.GIT_STATUS_CONFLICTED
+)
+
+type StatusEntry struct {
+	Status         Status
+	HeadToIndex    DiffDelta
+	IndexToWorkdir DiffDelta
+}
+
+func statusEntryFromC(statusEntry *C.git_status_entry) StatusEntry {
+	var headToIndex DiffDelta = DiffDelta{}
+	var indexToWorkdir DiffDelta = DiffDelta{}
+
+	// Based on the libgit2 status example, head_to_index can be null in some cases
+	if statusEntry.head_to_index != nil {
+		headToIndex = diffDeltaFromC(statusEntry.head_to_index)
+	}
+	if statusEntry.index_to_workdir != nil {
+		indexToWorkdir = diffDeltaFromC(statusEntry.index_to_workdir)
+	}
+
+	return StatusEntry{
+		Status:         Status(statusEntry.status),
+		HeadToIndex:    headToIndex,
+		IndexToWorkdir: indexToWorkdir,
+	}
+}
+
+type StatusList struct {
+	doNotCompare
+	ptr *C.git_status_list
+	r   *Repository
+}
+
+func newStatusListFromC(ptr *C.git_status_list, r *Repository) *StatusList {
+	if ptr == nil {
+		return nil
+	}
+
+	statusList := &StatusList{
+		ptr: ptr,
+		r:   r,
+	}
+
+	runtime.SetFinalizer(statusList, (*StatusList).Free)
+	return statusList
+}
+
+func (statusList *StatusList) Free() {
+	if statusList.ptr == nil {
+		return
+	}
+	runtime.SetFinalizer(statusList, nil)
+	C.git_status_list_free(statusList.ptr)
+	statusList.ptr = nil
+}
+
+func (statusList *StatusList) ByIndex(index int) (StatusEntry, error) {
+	if statusList.ptr == nil {
+		return StatusEntry{}, ErrInvalid
+	}
+	ptr := C.git_status_byindex(statusList.ptr, C.size_t(index))
+	if ptr == nil {
+		return StatusEntry{}, errors.New("index out of Bounds")
+	}
+	entry := statusEntryFromC(ptr)
+	runtime.KeepAlive(statusList)
+
+	return entry, nil
+}
+
+func (statusList *StatusList) EntryCount() (int, error) {
+	if statusList.ptr == nil {
+		return -1, ErrInvalid
+	}
+	ret := int(C.git_status_list_entrycount(statusList.ptr))
+	runtime.KeepAlive(statusList)
+
+	return ret, nil
+}
+
+type StatusOpt int
+
+const (
+	StatusOptIncludeUntracked      StatusOpt = C.GIT_STATUS_OPT_INCLUDE_UNTRACKED
+	StatusOptIncludeIgnored        StatusOpt = C.GIT_STATUS_OPT_INCLUDE_IGNORED
+	StatusOptIncludeUnmodified     StatusOpt = C.GIT_STATUS_OPT_INCLUDE_UNMODIFIED
+	StatusOptExcludeSubmodules     StatusOpt = C.GIT_STATUS_OPT_EXCLUDE_SUBMODULES
+	StatusOptRecurseUntrackedDirs  StatusOpt = C.GIT_STATUS_OPT_RECURSE_UNTRACKED_DIRS
+	StatusOptDisablePathspecMatch  StatusOpt = C.GIT_STATUS_OPT_DISABLE_PATHSPEC_MATCH
+	StatusOptRecurseIgnoredDirs    StatusOpt = C.GIT_STATUS_OPT_RECURSE_IGNORED_DIRS
+	StatusOptRenamesHeadToIndex    StatusOpt = C.GIT_STATUS_OPT_RENAMES_HEAD_TO_INDEX
+	StatusOptRenamesIndexToWorkdir StatusOpt = C.GIT_STATUS_OPT_RENAMES_INDEX_TO_WORKDIR
+	StatusOptSortCaseSensitively   StatusOpt = C.GIT_STATUS_OPT_SORT_CASE_SENSITIVELY
+	StatusOptSortCaseInsensitively StatusOpt = C.GIT_STATUS_OPT_SORT_CASE_INSENSITIVELY
+	StatusOptRenamesFromRewrites   StatusOpt = C.GIT_STATUS_OPT_RENAMES_FROM_REWRITES
+	StatusOptNoRefresh             StatusOpt = C.GIT_STATUS_OPT_NO_REFRESH
+	StatusOptUpdateIndex           StatusOpt = C.GIT_STATUS_OPT_UPDATE_INDEX
+)
+
+type StatusShow int
+
+const (
+	StatusShowIndexAndWorkdir StatusShow = C.GIT_STATUS_SHOW_INDEX_AND_WORKDIR
+	StatusShowIndexOnly       StatusShow = C.GIT_STATUS_SHOW_INDEX_ONLY
+	StatusShowWorkdirOnly     StatusShow = C.GIT_STATUS_SHOW_WORKDIR_ONLY
+)
+
+type StatusOptions struct {
+	Show     StatusShow
+	Flags    StatusOpt
+	Pathspec []string
+}
+
+func (v *Repository) StatusList(opts *StatusOptions) (*StatusList, error) {
+	var ptr *C.git_status_list
+	var copts *C.git_status_options
+
+	if opts != nil {
+		cpathspec := C.git_strarray{}
+		if opts.Pathspec != nil {
+			cpathspec.count = C.size_t(len(opts.Pathspec))
+			cpathspec.strings = makeCStringsFromStrings(opts.Pathspec)
+			defer freeStrarray(&cpathspec)
+		}
+
+		copts = &C.git_status_options{
+			version:  C.GIT_STATUS_OPTIONS_VERSION,
+			show:     C.git_status_show_t(opts.Show),
+			flags:    C.uint(opts.Flags),
+			pathspec: cpathspec,
+		}
+	} else {
+		copts = &C.git_status_options{}
+		ret := C.git_status_options_init(copts, C.GIT_STATUS_OPTIONS_VERSION)
+		if ret < 0 {
+			return nil, MakeGitError(ret)
+		}
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_status_list_new(&ptr, v.ptr, copts)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return newStatusListFromC(ptr, v), nil
+}
+
+func (v *Repository) StatusFile(path string) (Status, error) {
+	var statusFlags C.uint
+	cPath := C.CString(path)
+	defer C.free(unsafe.Pointer(cPath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_status_file(&statusFlags, v.ptr, cPath)
+	runtime.KeepAlive(v)
+	if ret < 0 {
+		return 0, MakeGitError(ret)
+	}
+	return Status(statusFlags), nil
+}

status_test.go

@@ -0,0 +1,91 @@
+package git
+
+import (
+	"io/ioutil"
+	"path"
+	"testing"
+)
+
+func TestStatusFile(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	state := repo.State()
+	if state != RepositoryStateNone {
+		t.Fatal("Incorrect repository state: ", state)
+	}
+
+	err := ioutil.WriteFile(path.Join(path.Dir(repo.Workdir()), "hello.txt"), []byte("Hello, World"), 0644)
+	checkFatal(t, err)
+
+	status, err := repo.StatusFile("hello.txt")
+	checkFatal(t, err)
+
+	if status != StatusWtNew {
+		t.Fatal("Incorrect status flags: ", status)
+	}
+}
+
+func TestStatusList(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	// This commits the test repo README, so it doesn't show up in the status list and there's a head to compare to
+	seedTestRepo(t, repo)
+
+	err := ioutil.WriteFile(path.Join(path.Dir(repo.Workdir()), "hello.txt"), []byte("Hello, World"), 0644)
+	checkFatal(t, err)
+
+	opts := &StatusOptions{}
+	opts.Show = StatusShowIndexAndWorkdir
+	opts.Flags = StatusOptIncludeUntracked | StatusOptRenamesHeadToIndex | StatusOptSortCaseSensitively
+
+	statusList, err := repo.StatusList(opts)
+	checkFatal(t, err)
+
+	entryCount, err := statusList.EntryCount()
+	checkFatal(t, err)
+
+	if entryCount != 1 {
+		t.Fatal("Incorrect number of status entries: ", entryCount)
+	}
+
+	entry, err := statusList.ByIndex(0)
+	checkFatal(t, err)
+	if entry.Status != StatusWtNew {
+		t.Fatal("Incorrect status flags: ", entry.Status)
+	}
+	if entry.IndexToWorkdir.NewFile.Path != "hello.txt" {
+		t.Fatal("Incorrect entry path: ", entry.IndexToWorkdir.NewFile.Path)
+	}
+}
+
+func TestStatusNothing(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	opts := &StatusOptions{
+		Show:  StatusShowIndexAndWorkdir,
+		Flags: StatusOptIncludeUntracked | StatusOptRenamesHeadToIndex | StatusOptSortCaseSensitively,
+	}
+
+	statusList, err := repo.StatusList(opts)
+	checkFatal(t, err)
+
+	entryCount, err := statusList.EntryCount()
+	checkFatal(t, err)
+
+	if entryCount != 0 {
+		t.Fatal("expected no statuses in empty repo")
+	}
+
+	_, err = statusList.ByIndex(0)
+	if err == nil {
+		t.Error("expected error getting status by index")
+	}
+}

submodule.go

@@ -1,263 +1,405 @@
 package git
 
 /*
-#cgo pkg-config: libgit2
 #include <git2.h>
-#include <git2/errors.h>
 
 extern int _go_git_visit_submodule(git_repository *repo, void *fct);
 */
 import "C"
+
 import (
+	"runtime"
 	"unsafe"
 )
 
+// SubmoduleUpdateOptions
+type SubmoduleUpdateOptions struct {
+	CheckoutOptions CheckoutOptions
+	FetchOptions    FetchOptions
+}
+
 // Submodule
 type Submodule struct {
+	doNotCompare
 	ptr *C.git_submodule
+	r   *Repository
+}
+
+func newSubmoduleFromC(ptr *C.git_submodule, r *Repository) *Submodule {
+	s := &Submodule{ptr: ptr, r: r}
+	runtime.SetFinalizer(s, (*Submodule).Free)
+	return s
+}
+
+func (sub *Submodule) Free() {
+	runtime.SetFinalizer(sub, nil)
+	C.git_submodule_free(sub.ptr)
 }
 
 type SubmoduleUpdate int
 
 const (
-	SubmoduleUpdateReset    SubmoduleUpdate = C.GIT_SUBMODULE_UPDATE_RESET
-	SubmoduleUpdateCheckout                 = C.GIT_SUBMODULE_UPDATE_CHECKOUT
-	SubmoduleUpdateRebase                   = C.GIT_SUBMODULE_UPDATE_REBASE
-	SubmoduleUpdateMerge                    = C.GIT_SUBMODULE_UPDATE_MERGE
-	SubmoduleUpdateNone                     = C.GIT_SUBMODULE_UPDATE_NONE
+	SubmoduleUpdateCheckout SubmoduleUpdate = C.GIT_SUBMODULE_UPDATE_CHECKOUT
+	SubmoduleUpdateRebase   SubmoduleUpdate = C.GIT_SUBMODULE_UPDATE_REBASE
+	SubmoduleUpdateMerge    SubmoduleUpdate = C.GIT_SUBMODULE_UPDATE_MERGE
+	SubmoduleUpdateNone     SubmoduleUpdate = C.GIT_SUBMODULE_UPDATE_NONE
 )
 
 type SubmoduleIgnore int
 
 const (
-	SubmoduleIgnoreReset     SubmoduleIgnore = C.GIT_SUBMODULE_IGNORE_RESET
-	SubmoduleIgnoreNone                      = C.GIT_SUBMODULE_IGNORE_NONE
-	SubmoduleIgnoreUntracked                 = C.GIT_SUBMODULE_IGNORE_UNTRACKED
-	SubmoduleIgnoreDirty                     = C.GIT_SUBMODULE_IGNORE_DIRTY
-	SubmoduleIgnoreAll                       = C.GIT_SUBMODULE_IGNORE_ALL
+	SubmoduleIgnoreNone      SubmoduleIgnore = C.GIT_SUBMODULE_IGNORE_NONE
+	SubmoduleIgnoreUntracked SubmoduleIgnore = C.GIT_SUBMODULE_IGNORE_UNTRACKED
+	SubmoduleIgnoreDirty     SubmoduleIgnore = C.GIT_SUBMODULE_IGNORE_DIRTY
+	SubmoduleIgnoreAll       SubmoduleIgnore = C.GIT_SUBMODULE_IGNORE_ALL
 )
 
 type SubmoduleStatus int
 
 const (
 	SubmoduleStatusInHead          SubmoduleStatus = C.GIT_SUBMODULE_STATUS_IN_HEAD
-	SubmoduleStatusInIndex                         = C.GIT_SUBMODULE_STATUS_IN_INDEX
-	SubmoduleStatusInConfig                        = C.GIT_SUBMODULE_STATUS_IN_CONFIG
-	SubmoduleStatusInWd                            = C.GIT_SUBMODULE_STATUS_IN_WD
-	SubmoduleStatusIndexAdded                      = C.GIT_SUBMODULE_STATUS_INDEX_ADDED
-	SubmoduleStatusIndexDeleted                    = C.GIT_SUBMODULE_STATUS_INDEX_DELETED
-	SubmoduleStatusIndexModified                   = C.GIT_SUBMODULE_STATUS_INDEX_MODIFIED
-	SubmoduleStatusWdUninitialized                 = C.GIT_SUBMODULE_STATUS_WD_UNINITIALIZED
-	SubmoduleStatusWdAdded                         = C.GIT_SUBMODULE_STATUS_WD_ADDED
-	SubmoduleStatusWdDeleted                       = C.GIT_SUBMODULE_STATUS_WD_DELETED
-	SubmoduleStatusWdModified                      = C.GIT_SUBMODULE_STATUS_WD_MODIFIED
-	SubmoduleStatusWdIndexModified                 = C.GIT_SUBMODULE_STATUS_WD_INDEX_MODIFIED
-	SubmoduleStatusWdWdModified                    = C.GIT_SUBMODULE_STATUS_WD_WD_MODIFIED
-	SubmoduleStatusWdUntracked                     = C.GIT_SUBMODULE_STATUS_WD_UNTRACKED
+	SubmoduleStatusInIndex         SubmoduleStatus = C.GIT_SUBMODULE_STATUS_IN_INDEX
+	SubmoduleStatusInConfig        SubmoduleStatus = C.GIT_SUBMODULE_STATUS_IN_CONFIG
+	SubmoduleStatusInWd            SubmoduleStatus = C.GIT_SUBMODULE_STATUS_IN_WD
+	SubmoduleStatusIndexAdded      SubmoduleStatus = C.GIT_SUBMODULE_STATUS_INDEX_ADDED
+	SubmoduleStatusIndexDeleted    SubmoduleStatus = C.GIT_SUBMODULE_STATUS_INDEX_DELETED
+	SubmoduleStatusIndexModified   SubmoduleStatus = C.GIT_SUBMODULE_STATUS_INDEX_MODIFIED
+	SubmoduleStatusWdUninitialized SubmoduleStatus = C.GIT_SUBMODULE_STATUS_WD_UNINITIALIZED
+	SubmoduleStatusWdAdded         SubmoduleStatus = C.GIT_SUBMODULE_STATUS_WD_ADDED
+	SubmoduleStatusWdDeleted       SubmoduleStatus = C.GIT_SUBMODULE_STATUS_WD_DELETED
+	SubmoduleStatusWdModified      SubmoduleStatus = C.GIT_SUBMODULE_STATUS_WD_MODIFIED
+	SubmoduleStatusWdIndexModified SubmoduleStatus = C.GIT_SUBMODULE_STATUS_WD_INDEX_MODIFIED
+	SubmoduleStatusWdWdModified    SubmoduleStatus = C.GIT_SUBMODULE_STATUS_WD_WD_MODIFIED
+	SubmoduleStatusWdUntracked     SubmoduleStatus = C.GIT_SUBMODULE_STATUS_WD_UNTRACKED
 )
 
+type SubmoduleRecurse int
+
+const (
+	SubmoduleRecurseNo       SubmoduleRecurse = C.GIT_SUBMODULE_RECURSE_NO
+	SubmoduleRecurseYes      SubmoduleRecurse = C.GIT_SUBMODULE_RECURSE_YES
+	SubmoduleRecurseOndemand SubmoduleRecurse = C.GIT_SUBMODULE_RECURSE_ONDEMAND
+)
+
+type SubmoduleCollection struct {
+	doNotCompare
+	repo *Repository
+}
+
 func SubmoduleStatusIsUnmodified(status int) bool {
 	o := SubmoduleStatus(status) & ^(SubmoduleStatusInHead | SubmoduleStatusInIndex |
 		SubmoduleStatusInConfig | SubmoduleStatusInWd)
 	return o == 0
 }
 
-func (repo *Repository) LookupSubmodule(name string) (*Submodule, error) {
+func (c *SubmoduleCollection) Lookup(name string) (*Submodule, error) {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
 
-	sub := new(Submodule)
-	ret := C.git_submodule_lookup(&sub.ptr, repo.ptr, cname)
+	var ptr *C.git_submodule
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_submodule_lookup(&ptr, c.repo.ptr, cname)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
 
-	return sub, nil
+	return newSubmoduleFromC(ptr, c.repo), nil
 }
 
-type SubmoduleCbk func(sub *Submodule, name string) int
-
-//export SubmoduleVisitor
-func SubmoduleVisitor(csub unsafe.Pointer, name string, cfct unsafe.Pointer) int {
-	sub := &Submodule{(*C.git_submodule)(csub)}
-	fct := *(*SubmoduleCbk)(cfct)
-	return fct(sub, name)
+// SubmoduleCallback is a function that is called for every submodule found in SubmoduleCollection.Foreach.
+type SubmoduleCallback func(sub *Submodule, name string) error
+type submoduleCallbackData struct {
+	callback    SubmoduleCallback
+	errorTarget *error
 }
 
-func (repo *Repository) ForeachSubmodule(cbk SubmoduleCbk) error {
-	ret := C._go_git_visit_submodule(repo.ptr, unsafe.Pointer(&cbk))
-	if ret < 0 {
-		return LastError()
+//export submoduleCallback
+func submoduleCallback(csub unsafe.Pointer, name *C.char, handle unsafe.Pointer) C.int {
+	sub := &Submodule{ptr: (*C.git_submodule)(csub)}
+
+	data, ok := pointerHandles.Get(handle).(submoduleCallbackData)
+	if !ok {
+		panic("invalid submodule visitor callback")
 	}
+
+	err := data.callback(sub, C.GoString(name))
+	if err != nil {
+		*data.errorTarget = err
+		return C.int(ErrorCodeUser)
+	}
+
+	return C.int(ErrorCodeOK)
+}
+
+func (c *SubmoduleCollection) Foreach(callback SubmoduleCallback) error {
+	var err error
+	data := submoduleCallbackData{
+		callback:    callback,
+		errorTarget: &err,
+	}
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	handle := pointerHandles.Track(data)
+	defer pointerHandles.Untrack(handle)
+
+	ret := C._go_git_visit_submodule(c.repo.ptr, handle)
+	runtime.KeepAlive(c)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
 	return nil
 }
 
-func (repo *Repository) AddSubmodule(url, path string, use_git_link bool) (*Submodule, error) {
+func (c *SubmoduleCollection) Add(url, path string, use_git_link bool) (*Submodule, error) {
 	curl := C.CString(url)
 	defer C.free(unsafe.Pointer(curl))
 	cpath := C.CString(path)
 	defer C.free(unsafe.Pointer(cpath))
 
-	sub := new(Submodule)
-	ret := C.git_submodule_add_setup(&sub.ptr, repo.ptr, curl, cpath, cbool(use_git_link))
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_submodule
+	ret := C.git_submodule_add_setup(&ptr, c.repo.ptr, curl, cpath, cbool(use_git_link))
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
-	return sub, nil
+	return newSubmoduleFromC(ptr, c.repo), nil
 }
 
 func (sub *Submodule) FinalizeAdd() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_submodule_add_finalize(sub.ptr)
+	runtime.KeepAlive(sub)
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 	return nil
 }
 
 func (sub *Submodule) AddToIndex(write_index bool) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_submodule_add_to_index(sub.ptr, cbool(write_index))
+	runtime.KeepAlive(sub)
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 	return nil
 }
 
-func (sub *Submodule) Save() error {
-	ret := C.git_submodule_save(sub.ptr)
-	if ret < 0 {
-		return LastError()
-	}
-	return nil
-}
-
-func (sub *Submodule) Owner() *Repository {
-	repo := C.git_submodule_owner(sub.ptr)
-	//FIXME: how to handle dangling references ?
-	return &Repository{repo}
-}
-
 func (sub *Submodule) Name() string {
-	n := C.git_submodule_name(sub.ptr)
-	return C.GoString(n)
+	n := C.GoString(C.git_submodule_name(sub.ptr))
+	runtime.KeepAlive(sub)
+	return n
 }
 
 func (sub *Submodule) Path() string {
-	n := C.git_submodule_path(sub.ptr)
-	return C.GoString(n)
+	n := C.GoString(C.git_submodule_path(sub.ptr))
+	runtime.KeepAlive(sub)
+	return n
 }
 
 func (sub *Submodule) Url() string {
-	n := C.git_submodule_url(sub.ptr)
-	return C.GoString(n)
+	n := C.GoString(C.git_submodule_url(sub.ptr))
+	runtime.KeepAlive(sub)
+	return n
 }
 
-func (sub *Submodule) SetUrl(url string) error {
+func (c *SubmoduleCollection) SetUrl(submodule, url string) error {
+	csubmodule := C.CString(submodule)
+	defer C.free(unsafe.Pointer(csubmodule))
 	curl := C.CString(url)
 	defer C.free(unsafe.Pointer(curl))
 
-	ret := C.git_submodule_set_url(sub.ptr, curl)
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_submodule_set_url(c.repo.ptr, csubmodule, curl)
+	runtime.KeepAlive(c)
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 	return nil
 }
 
 func (sub *Submodule) IndexId() *Oid {
+	var id *Oid
 	idx := C.git_submodule_index_id(sub.ptr)
-	if idx == nil {
-		return nil
+	if idx != nil {
+		id = newOidFromC(idx)
 	}
-	return newOidFromC(idx)
+	runtime.KeepAlive(sub)
+	return id
 }
 
 func (sub *Submodule) HeadId() *Oid {
+	var id *Oid
 	idx := C.git_submodule_head_id(sub.ptr)
-	if idx == nil {
-		return nil
+	if idx != nil {
+		id = newOidFromC(idx)
 	}
-	return newOidFromC(idx)
+	runtime.KeepAlive(sub)
+	return id
 }
 
 func (sub *Submodule) WdId() *Oid {
+	var id *Oid
 	idx := C.git_submodule_wd_id(sub.ptr)
-	if idx == nil {
-		return nil
+	if idx != nil {
+		id = newOidFromC(idx)
 	}
-	return newOidFromC(idx)
+	runtime.KeepAlive(sub)
+	return id
 }
 
 func (sub *Submodule) Ignore() SubmoduleIgnore {
 	o := C.git_submodule_ignore(sub.ptr)
+	runtime.KeepAlive(sub)
 	return SubmoduleIgnore(o)
 }
 
-func (sub *Submodule) SetIgnore(ignore SubmoduleIgnore) SubmoduleIgnore {
-	o := C.git_submodule_set_ignore(sub.ptr, C.git_submodule_ignore_t(ignore))
-	return SubmoduleIgnore(o)
-}
+func (c *SubmoduleCollection) SetIgnore(submodule string, ignore SubmoduleIgnore) error {
+	csubmodule := C.CString(submodule)
+	defer C.free(unsafe.Pointer(csubmodule))
 
-func (sub *Submodule) Update() SubmoduleUpdate {
-	o := C.git_submodule_update(sub.ptr)
-	return SubmoduleUpdate(o)
-}
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
 
-func (sub *Submodule) SetUpdate(update SubmoduleUpdate) SubmoduleUpdate {
-	o := C.git_submodule_set_update(sub.ptr, C.git_submodule_update_t(update))
-	return SubmoduleUpdate(o)
-}
-
-func (sub *Submodule) FetchRecurseSubmodules() bool {
-	if 0 == C.git_submodule_fetch_recurse_submodules(sub.ptr) {
-		return false
-	}
-	return true
-}
-
-func (sub *Submodule) SetFetchRecurseSubmodules(v bool) error {
-	ret := C.git_submodule_set_fetch_recurse_submodules(sub.ptr, cbool(v))
+	ret := C.git_submodule_set_ignore(c.repo.ptr, csubmodule, C.git_submodule_ignore_t(ignore))
+	runtime.KeepAlive(c)
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (sub *Submodule) UpdateStrategy() SubmoduleUpdate {
+	o := C.git_submodule_update_strategy(sub.ptr)
+	runtime.KeepAlive(sub)
+	return SubmoduleUpdate(o)
+}
+
+func (c *SubmoduleCollection) SetUpdate(submodule string, update SubmoduleUpdate) error {
+	csubmodule := C.CString(submodule)
+	defer C.free(unsafe.Pointer(csubmodule))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_submodule_set_update(c.repo.ptr, csubmodule, C.git_submodule_update_t(update))
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+func (sub *Submodule) FetchRecurseSubmodules() SubmoduleRecurse {
+	return SubmoduleRecurse(C.git_submodule_fetch_recurse_submodules(sub.ptr))
+}
+
+func (c *SubmoduleCollection) SetFetchRecurseSubmodules(submodule string, recurse SubmoduleRecurse) error {
+	csubmodule := C.CString(submodule)
+	defer C.free(unsafe.Pointer(csubmodule))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_submodule_set_fetch_recurse_submodules(c.repo.ptr, csubmodule, C.git_submodule_recurse_t(recurse))
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(C.int(ret))
 	}
 	return nil
 }
 
 func (sub *Submodule) Init(overwrite bool) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_submodule_init(sub.ptr, cbool(overwrite))
+	runtime.KeepAlive(sub)
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 	return nil
 }
 
 func (sub *Submodule) Sync() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
 	ret := C.git_submodule_sync(sub.ptr)
+	runtime.KeepAlive(sub)
 	if ret < 0 {
-		return LastError()
+		return MakeGitError(ret)
 	}
 	return nil
 }
 
 func (sub *Submodule) Open() (*Repository, error) {
-	repo := new(Repository)
-	ret := C.git_submodule_open(&repo.ptr, sub.ptr)
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	var ptr *C.git_repository
+	ret := C.git_submodule_open(&ptr, sub.ptr)
+	runtime.KeepAlive(sub)
 	if ret < 0 {
-		return nil, LastError()
+		return nil, MakeGitError(ret)
 	}
-	return repo, nil
+	return newRepositoryFromC(ptr), nil
 }
 
-func (sub *Submodule) Reload() error {
-	ret := C.git_submodule_reload(sub.ptr)
-	if ret < 0 {
-		return LastError()
+func (sub *Submodule) Update(init bool, opts *SubmoduleUpdateOptions) error {
+	var err error
+	cOpts := populateSubmoduleUpdateOptions(&C.git_submodule_update_options{}, opts, &err)
+	defer freeSubmoduleUpdateOptions(cOpts)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_submodule_update(sub.ptr, cbool(init), cOpts)
+	runtime.KeepAlive(sub)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
 	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
 	return nil
 }
 
-func (repo *Repository) ReloadAllSubmodules() error {
-	ret := C.git_submodule_reload_all(repo.ptr)
-	if ret < 0 {
-		return LastError()
+func populateSubmoduleUpdateOptions(copts *C.git_submodule_update_options, opts *SubmoduleUpdateOptions, errorTarget *error) *C.git_submodule_update_options {
+	C.git_submodule_update_options_init(copts, C.GIT_SUBMODULE_UPDATE_OPTIONS_VERSION)
+	if opts == nil {
+		return nil
 	}
-	return nil
+
+	populateCheckoutOptions(&copts.checkout_opts, &opts.CheckoutOptions, errorTarget)
+	populateFetchOptions(&copts.fetch_opts, &opts.FetchOptions, errorTarget)
+
+	return copts
+}
+
+func freeSubmoduleUpdateOptions(copts *C.git_submodule_update_options) {
+	if copts == nil {
+		return
+	}
+	freeCheckoutOptions(&copts.checkout_opts)
+	freeFetchOptions(&copts.fetch_opts)
 }

submodule_test.go

@@ -0,0 +1,27 @@
+package git
+
+import (
+	"testing"
+)
+
+func TestSubmoduleForeach(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	seedTestRepo(t, repo)
+
+	_, err := repo.Submodules.Add("http://example.org/submodule", "submodule", true)
+	checkFatal(t, err)
+
+	i := 0
+	err = repo.Submodules.Foreach(func(sub *Submodule, name string) error {
+		i++
+		return nil
+	})
+	checkFatal(t, err)
+
+	if i != 1 {
+		t.Fatalf("expected one submodule found but got %d", i)
+	}
+}

tag.go

@@ -0,0 +1,247 @@
+package git
+
+/*
+#include <git2.h>
+
+extern int _go_git_tag_foreach(git_repository *repo, void *payload);
+*/
+import "C"
+import (
+	"runtime"
+	"unsafe"
+)
+
+// Tag
+type Tag struct {
+	doNotCompare
+	Object
+	cast_ptr *C.git_tag
+}
+
+func (t *Tag) AsObject() *Object {
+	return &t.Object
+}
+
+func (t *Tag) Message() string {
+	ret := C.GoString(C.git_tag_message(t.cast_ptr))
+	runtime.KeepAlive(t)
+	return ret
+}
+
+func (t *Tag) Name() string {
+	ret := C.GoString(C.git_tag_name(t.cast_ptr))
+	runtime.KeepAlive(t)
+	return ret
+}
+
+func (t *Tag) Tagger() *Signature {
+	cast_ptr := C.git_tag_tagger(t.cast_ptr)
+	ret := newSignatureFromC(cast_ptr)
+	runtime.KeepAlive(t)
+	return ret
+}
+
+func (t *Tag) Target() *Object {
+	var ptr *C.git_object
+	ret := C.git_tag_target(&ptr, t.cast_ptr)
+	runtime.KeepAlive(t)
+	if ret != 0 {
+		return nil
+	}
+
+	return allocObject(ptr, t.repo)
+}
+
+func (t *Tag) TargetId() *Oid {
+	ret := newOidFromC(C.git_tag_target_id(t.cast_ptr))
+	runtime.KeepAlive(t)
+	return ret
+}
+
+func (t *Tag) TargetType() ObjectType {
+	ret := ObjectType(C.git_tag_target_type(t.cast_ptr))
+	runtime.KeepAlive(t)
+	return ret
+}
+
+type TagsCollection struct {
+	doNotCompare
+	repo *Repository
+}
+
+func (c *TagsCollection) Create(name string, obj Objecter, tagger *Signature, message string) (*Oid, error) {
+
+	oid := new(Oid)
+
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	cmessage := C.CString(message)
+	defer C.free(unsafe.Pointer(cmessage))
+
+	taggerSig, err := tagger.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(taggerSig)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	o := obj.AsObject()
+	ret := C.git_tag_create(oid.toC(), c.repo.ptr, cname, o.ptr, taggerSig, cmessage, 0)
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(obj)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return oid, nil
+}
+
+func (c *TagsCollection) Remove(name string) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	ret := C.git_tag_delete(c.repo.ptr, cname)
+	runtime.KeepAlive(c)
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
+// CreateLightweight creates a new lightweight tag pointing to an object
+// and returns the id of the target object.
+//
+// The name of the tag is validated for consistency (see git_tag_create() for the rules
+// https://libgit2.github.com/libgit2/#HEAD/group/tag/git_tag_create) and should
+// not conflict with an already existing tag name.
+//
+// If force is true and a reference already exists with the given name, it'll be replaced.
+//
+// The created tag is a simple reference and can be queried using
+// repo.References.Lookup("refs/tags/<name>"). The name of the tag (eg "v1.0.0")
+// is queried with ref.Shorthand().
+func (c *TagsCollection) CreateLightweight(name string, obj Objecter, force bool) (*Oid, error) {
+
+	oid := new(Oid)
+
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	o := obj.AsObject()
+	err := C.git_tag_create_lightweight(oid.toC(), c.repo.ptr, cname, o.ptr, cbool(force))
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(obj)
+	if err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return oid, nil
+}
+
+// List returns the names of all the tags in the repository,
+// eg: ["v1.0.1", "v2.0.0"].
+func (c *TagsCollection) List() ([]string, error) {
+	var strC C.git_strarray
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_tag_list(&strC, c.repo.ptr)
+	runtime.KeepAlive(c)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+	defer C.git_strarray_dispose(&strC)
+
+	tags := makeStringsFromCStrings(strC.strings, int(strC.count))
+	return tags, nil
+}
+
+// ListWithMatch returns the names of all the tags in the repository
+// that match a given pattern.
+//
+// The pattern is a standard fnmatch(3) pattern http://man7.org/linux/man-pages/man3/fnmatch.3.html
+func (c *TagsCollection) ListWithMatch(pattern string) ([]string, error) {
+	var strC C.git_strarray
+
+	patternC := C.CString(pattern)
+	defer C.free(unsafe.Pointer(patternC))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_tag_list_match(&strC, patternC, c.repo.ptr)
+	runtime.KeepAlive(c)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+	defer C.git_strarray_dispose(&strC)
+
+	tags := makeStringsFromCStrings(strC.strings, int(strC.count))
+	return tags, nil
+}
+
+// TagForeachCallback is called for each tag in the repository.
+//
+// The name is the full ref name eg: "refs/tags/v1.0.0".
+//
+// Note that the callback is called for lightweight tags as well,
+// so repo.LookupTag() will return an error for these tags. Use
+// repo.References.Lookup() instead.
+type TagForeachCallback func(name string, id *Oid) error
+type tagForeachCallbackData struct {
+	callback    TagForeachCallback
+	errorTarget *error
+}
+
+//export tagForeachCallback
+func tagForeachCallback(name *C.char, id *C.git_oid, handle unsafe.Pointer) C.int {
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*tagForeachCallbackData)
+	if !ok {
+		panic("could not retrieve tag foreach CB handle")
+	}
+
+	err := data.callback(C.GoString(name), newOidFromC(id))
+	if err != nil {
+		*data.errorTarget = err
+		return C.int(ErrorCodeUser)
+	}
+
+	return C.int(ErrorCodeOK)
+}
+
+// Foreach calls the callback for each tag in the repository.
+func (c *TagsCollection) Foreach(callback TagForeachCallback) error {
+	var err error
+	data := tagForeachCallbackData{
+		callback:    callback,
+		errorTarget: &err,
+	}
+	handle := pointerHandles.Track(&data)
+	defer pointerHandles.Untrack(handle)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C._go_git_tag_foreach(c.repo.ptr, handle)
+	runtime.KeepAlive(c)
+	if ret == C.int(ErrorCodeUser) && err != nil {
+		return err
+	}
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}

tag_test.go

@@ -0,0 +1,205 @@
+package git
+
+import (
+	"errors"
+	"testing"
+	"time"
+)
+
+func TestCreateTag(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitId, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitId)
+	checkFatal(t, err)
+
+	tagId := createTestTag(t, repo, commit)
+
+	tag, err := repo.LookupTag(tagId)
+	checkFatal(t, err)
+
+	compareStrings(t, "v0.0.0", tag.Name())
+	compareStrings(t, "This is a tag", tag.Message())
+	compareStrings(t, commitId.String(), tag.TargetId().String())
+}
+
+func TestCreateTagLightweight(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitID, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	tagID, err := repo.Tags.CreateLightweight("v0.1.0", commit, false)
+	checkFatal(t, err)
+
+	_, err = repo.Tags.CreateLightweight("v0.1.0", commit, true)
+	checkFatal(t, err)
+
+	ref, err := repo.References.Lookup("refs/tags/v0.1.0")
+	checkFatal(t, err)
+
+	compareStrings(t, "refs/tags/v0.1.0", ref.Name())
+	compareStrings(t, "v0.1.0", ref.Shorthand())
+	compareStrings(t, tagID.String(), commitID.String())
+	compareStrings(t, commitID.String(), ref.Target().String())
+}
+
+func TestListTags(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitID, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	createTag(t, repo, commit, "v1.0.1", "Release v1.0.1")
+
+	commitID, _ = updateReadme(t, repo, "Release version 2")
+
+	commit, err = repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	createTag(t, repo, commit, "v2.0.0", "Release v2.0.0")
+
+	expected := []string{
+		"v1.0.1",
+		"v2.0.0",
+	}
+
+	actual, err := repo.Tags.List()
+	checkFatal(t, err)
+
+	compareStringList(t, expected, actual)
+}
+
+func TestListTagsWithMatch(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitID, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	createTag(t, repo, commit, "v1.0.1", "Release v1.0.1")
+
+	commitID, _ = updateReadme(t, repo, "Release version 2")
+
+	commit, err = repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	createTag(t, repo, commit, "v2.0.0", "Release v2.0.0")
+
+	expected := []string{
+		"v2.0.0",
+	}
+
+	actual, err := repo.Tags.ListWithMatch("v2*")
+	checkFatal(t, err)
+
+	compareStringList(t, expected, actual)
+
+	expected = []string{
+		"v1.0.1",
+	}
+
+	actual, err = repo.Tags.ListWithMatch("v1*")
+	checkFatal(t, err)
+
+	compareStringList(t, expected, actual)
+}
+
+func TestTagForeach(t *testing.T) {
+	t.Parallel()
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	commitID, _ := seedTestRepo(t, repo)
+
+	commit, err := repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	tag1 := createTag(t, repo, commit, "v1.0.1", "Release v1.0.1")
+
+	commitID, _ = updateReadme(t, repo, "Release version 2")
+
+	commit, err = repo.LookupCommit(commitID)
+	checkFatal(t, err)
+
+	tag2 := createTag(t, repo, commit, "v2.0.0", "Release v2.0.0")
+
+	expectedNames := []string{
+		"refs/tags/v1.0.1",
+		"refs/tags/v2.0.0",
+	}
+	actualNames := []string{}
+	expectedOids := []string{
+		tag1.String(),
+		tag2.String(),
+	}
+	actualOids := []string{}
+
+	err = repo.Tags.Foreach(func(name string, id *Oid) error {
+		actualNames = append(actualNames, name)
+		actualOids = append(actualOids, id.String())
+		return nil
+	})
+	checkFatal(t, err)
+
+	compareStringList(t, expectedNames, actualNames)
+	compareStringList(t, expectedOids, actualOids)
+
+	fakeErr := errors.New("fake error")
+
+	err = repo.Tags.Foreach(func(name string, id *Oid) error {
+		return fakeErr
+	})
+
+	if err != fakeErr {
+		t.Fatalf("Tags.Foreach() did not return the expected error, got %v", err)
+	}
+}
+
+func compareStrings(t *testing.T, expected, value string) {
+	if value != expected {
+		t.Fatalf("expected '%v', actual '%v'", expected, value)
+	}
+}
+
+func createTestTag(t *testing.T, repo *Repository, commit *Commit) *Oid {
+	loc, err := time.LoadLocation("Europe/Berlin")
+	checkFatal(t, err)
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Date(2013, 03, 06, 14, 30, 0, 0, loc),
+	}
+
+	tagId, err := repo.Tags.Create("v0.0.0", commit, sig, "This is a tag")
+	checkFatal(t, err)
+	return tagId
+}
+
+func createTag(t *testing.T, repo *Repository, commit *Commit, name, message string) *Oid {
+	loc, err := time.LoadLocation("Europe/Bucharest")
+	checkFatal(t, err)
+	sig := &Signature{
+		Name:  "Rand Om Hacker",
+		Email: "random@hacker.com",
+		When:  time.Date(2013, 03, 06, 14, 30, 0, 0, loc),
+	}
+
+	tagId, err := repo.Tags.Create(name, commit, sig, message)
+	checkFatal(t, err)
+	return tagId
+}

testdata/TestGitRepository.git/HEAD

@@ -0,0 +1 @@
+ref: refs/heads/master

testdata/TestGitRepository.git/config

@@ -0,0 +1,6 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true
+[remote "origin"]
+	url = https://github.com/libgit2/TestGitRepository

testdata/TestGitRepository.git/description

@@ -0,0 +1 @@
+Unnamed repository; edit this file 'description' to name the repository.

testdata/TestGitRepository.git/info/exclude

@@ -0,0 +1,6 @@
+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~

testdata/TestGitRepository.git/info/refs

@@ -0,0 +1,8 @@
+0966a434eb1a025db6b71485ab63a3bfbea520b6	refs/heads/first-merge
+49322bb17d3acc9146f98c97d078513228bbf3c0	refs/heads/master
+42e4e7c5e507e113ebbb7801b16b52cf867b7ce1	refs/heads/no-parent
+d96c4e80345534eccee5ac7b07fc7603b56124cb	refs/tags/annotated_tag
+c070ad8c08840c8116da865b2d65593a6bb9cd2a	refs/tags/annotated_tag^{}
+55a1a760df4b86a02094a904dfa511deb5655905	refs/tags/blob
+8f50ba15d49353813cc6e20298002c0d17b0a9ee	refs/tags/commit_tree
+6e0c7bdb9b4ed93212491ee778ca1c65047cab4e	refs/tags/nearly-dangling

testdata/TestGitRepository.git/objects/info/packs

@@ -0,0 +1,2 @@
+P pack-ccace4e169a0858c13d9ae781a91d76fc33769b8.pack
+