add support for annotated tags

object.go

@@ -100,6 +100,13 @@ func allocObject(cobj *C.git_object, repo *Repository) Object {
 		}
 		runtime.SetFinalizer(blob, (*Blob).Free)
 		return blob
+	case ObjectTag:
+		tag := &Tag{
+			gitObject: obj,
+			cast_ptr:  (*C.git_tag)(cobj),
+		}
+		runtime.SetFinalizer(tag, (*Tag).Free)
+		return tag
 	}
 
 	return nil

repository.go

@@ -164,6 +164,15 @@ func (v *Repository) LookupBlob(id *Oid) (*Blob, error) {
 	return obj.(*Blob), nil
 }
 
+func (v *Repository) LookupTag(id *Oid) (*Tag, error) {
+	obj, err := v.lookupType(id, ObjectTag)
+	if err != nil {
+		return nil, err
+	}
+
+	return obj.(*Tag), nil
+}
+
 func (v *Repository) LookupReference(name string) (*Reference, error) {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
@@ -356,6 +365,30 @@ func (v *Repository) CreateCommit(
 	return oid, nil
 }
 
+func (v *Repository) CreateTag(
+	name string, commit *Commit, 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 := tagger.toC()
+	defer C.git_signature_free(taggerSig)
+
+  ctarget := commit.gitObject.ptr
+
+	ret := C.git_tag_create(oid.toC(), v.ptr, cname, ctarget, taggerSig, cmessage, 0)
+	if ret < 0 {
+		return nil, MakeGitError(ret)
+	}
+
+	return oid, nil
+}
+
 func (v *Odb) Free() {
 	runtime.SetFinalizer(v, nil)
 	C.git_odb_free(v.ptr)

tag.go

@@ -0,0 +1,44 @@
+package git
+
+/*
+#include <git2.h>
+*/
+import "C"
+
+// Tag
+type Tag struct {
+	gitObject
+	cast_ptr *C.git_tag
+}
+
+func (t Tag) Message() string {
+	return C.GoString(C.git_tag_message(t.cast_ptr))
+}
+
+func (t Tag) Name() string {
+	return C.GoString(C.git_tag_name(t.cast_ptr))
+}
+
+func (t Tag) Tagger() *Signature {
+	cast_ptr := C.git_tag_tagger(t.cast_ptr)
+	return newSignatureFromC(cast_ptr)
+}
+
+func (t Tag) Target() Object {
+	var ptr *C.git_object
+	ret := C.git_tag_target(&ptr, t.cast_ptr)
+
+	if ret != 0 {
+		return nil
+	}
+
+	return allocObject(ptr, t.repo)
+}
+
+func (t Tag) TargetId() *Oid {
+	return newOidFromC(C.git_tag_target_id(t.cast_ptr))
+}
+
+func (t Tag) TargetType() ObjectType {
+	return ObjectType(C.git_tag_target_type(t.cast_ptr))
+}

tag_test.go

@@ -0,0 +1,45 @@
+package git
+
+import (
+	"os"
+	"time"
+	"testing"
+)
+
+func TestCreateTag(t *testing.T) {
+	repo := createTestRepo(t)
+	defer os.RemoveAll(repo.Workdir())
+	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 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.CreateTag("v0.0.0", commit, sig, "This is a tag")
+	checkFatal(t, err)
+	return tagId
+}