Bring back the RevWalk

repository.go

@@ -81,6 +81,18 @@ func (v *Repository) LookupCommit(o *Oid) (*Commit, error) {
 	return commit, nil
 }
 
+func (v *Repository) Walk() (*RevWalk, error) {
+	walk := new(RevWalk)
+	ecode := C.git_revwalk_new(&walk.ptr, v.ptr)
+	if ecode < 0 {
+		return nil, LastError()
+	}
+
+	walk.repo = v
+	runtime.SetFinalizer(walk, freeRevWalk)
+	return walk, nil
+}
+
 /* TODO 
 func (v *Repository) Commit(
 	refname string, author, committer *Signature,

walk.go

@@ -0,0 +1,90 @@
+package git
+
+/*
+#cgo pkg-config: libgit2
+#include <git2.h>
+#include <git2/errors.h>
+*/
+import "C"
+
+import (
+	"io"
+)
+
+// RevWalk
+
+const (
+	SORT_NONE        = C.GIT_SORT_NONE
+	SORT_TOPOLOGICAL = C.GIT_SORT_TOPOLOGICAL
+	SORT_TIME        = C.GIT_SORT_TIME
+	SORT_REVERSE     = C.GIT_SORT_REVERSE
+)
+
+type RevWalk struct {
+	ptr  *C.git_revwalk
+	repo *Repository
+}
+
+func (v *RevWalk) Reset() {
+	C.git_revwalk_reset(v.ptr)
+}
+
+func (v *RevWalk) Push(id *Oid) {
+	C.git_revwalk_push(v.ptr, id.toC())
+}
+
+func (v *RevWalk) PushHead() (err error) {
+	ecode := C.git_revwalk_push_head(v.ptr)
+	if ecode < 0 {
+		err = LastError()
+	}
+
+	return
+}
+
+func (v *RevWalk) Next(oid *Oid) (err error) {
+	ret := C.git_revwalk_next(oid.toC(), v.ptr)
+	switch {
+	case ret == ITEROVER:
+		err = io.EOF
+	case ret < 0:
+		err = LastError()
+	}
+
+	return
+}
+
+type RevWalkIterator func(commit *Commit) bool
+
+func (v *RevWalk) Iterate(fun RevWalkIterator) (err error) {
+	oid := new(Oid)
+	for {
+		err = v.Next(oid)
+		if err == io.EOF {
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+
+		commit, err := v.repo.LookupCommit(oid)
+		if err != nil {
+			return err
+		}
+
+		cont := fun(commit)
+		if !cont {
+			break
+		}
+	}
+
+	return nil
+}
+
+func (v *RevWalk) Sorting(sm uint) {
+	C.git_revwalk_sorting(v.ptr, C.uint(sm))
+}
+
+func freeRevWalk(walk *RevWalk) {
+	C.git_revwalk_free(walk.ptr)
+}