storage: filesystem/dotgit, Improve load packed-refs

2 files changed, 39 insertions, 43 deletions

diff --git a/plumbing/reference_test.go b/plumbing/reference_test.go
index e69076f..04dfef9 100644
--- a/plumbing/reference_test.go
+++ b/plumbing/reference_test.go
@@ -105,7 +105,7 @@ func (s *ReferenceSuite) TestIsTag(c *C) {
 
 func benchMarkReferenceString(r *Reference, b *testing.B) {
 	for n := 0; n < b.N; n++ {
-		r.String()
+		_ = r.String()
 	}
 }
 
diff --git a/storage/filesystem/dotgit/dotgit.go b/storage/filesystem/dotgit/dotgit.go
index 6868324..5bde37f 100644
--- a/storage/filesystem/dotgit/dotgit.go
+++ b/storage/filesystem/dotgit/dotgit.go
@@ -718,48 +718,56 @@ func (d *DotGit) Ref(name plumbing.ReferenceName) (*plumbing.Reference, error) {
 	return d.packedRef(name)
 }
 
-func (d *DotGit) findPackedRefsInFile(f billy.File) ([]*plumbing.Reference, error) {
+func (d *DotGit) findPackedRefsInFile(f billy.File, recv refsRecv) error {
 	s := bufio.NewScanner(f)
-	var refs []*plumbing.Reference
 	for s.Scan() {
 		ref, err := d.processLine(s.Text())
 		if err != nil {
-			return nil, err
+			return err
 		}
 
-		if ref != nil {
-			refs = append(refs, ref)
+		if !recv(ref) {
+			// skip parse
+			return nil
 		}
 	}
-
-	return refs, s.Err()
+	if err := s.Err(); err != nil {
+		return err
+	}
+	return nil
 }
 
-func (d *DotGit) findPackedRefs() (r []*plumbing.Reference, err error) {
+// refsRecv: returning true means that the reference continues to be resolved, otherwise it is stopped, which will speed up the lookup of a single reference.
+type refsRecv func(*plumbing.Reference) bool
+
+func (d *DotGit) findPackedRefs(recv refsRecv) error {
 	f, err := d.fs.Open(packedRefsPath)
 	if err != nil {
 		if os.IsNotExist(err) {
-			return nil, nil
+			return nil
 		}
-		return nil, err
+		return err
 	}
 
 	defer ioutil.CheckClose(f, &err)
-	return d.findPackedRefsInFile(f)
+	return d.findPackedRefsInFile(f, recv)
 }
 
 func (d *DotGit) packedRef(name plumbing.ReferenceName) (*plumbing.Reference, error) {
-	refs, err := d.findPackedRefs()
-	if err != nil {
+	var ref *plumbing.Reference
+	if err := d.findPackedRefs(func(r *plumbing.Reference) bool {
+		if r != nil && r.Name() == name {
+			ref = r
+			// ref found
+			return false
+		}
+		return true
+	}); err != nil {
 		return nil, err
 	}
-
-	for _, ref := range refs {
-		if ref.Name() == name {
-			return ref, nil
-		}
+	if ref != nil {
+		return ref, nil
 	}
-
 	return nil, plumbing.ErrReferenceNotFound
 }
 
@@ -779,34 +787,22 @@ func (d *DotGit) RemoveRef(name plumbing.ReferenceName) error {
 	return d.rewritePackedRefsWithoutRef(name)
 }
 
-func (d *DotGit) addRefsFromPackedRefs(refs *[]*plumbing.Reference, seen map[plumbing.ReferenceName]bool) (err error) {
-	packedRefs, err := d.findPackedRefs()
-	if err != nil {
-		return err
-	}
-
-	for _, ref := range packedRefs {
-		if !seen[ref.Name()] {
-			*refs = append(*refs, ref)
-			seen[ref.Name()] = true
+func refsRecvFunc(refs *[]*plumbing.Reference, seen map[plumbing.ReferenceName]bool) refsRecv {
+	return func(r *plumbing.Reference) bool {
+		if r != nil && !seen[r.Name()] {
+			*refs = append(*refs, r)
+			seen[r.Name()] = true
 		}
+		return true
 	}
-	return nil
 }
 
-func (d *DotGit) addRefsFromPackedRefsFile(refs *[]*plumbing.Reference, f billy.File, seen map[plumbing.ReferenceName]bool) (err error) {
-	packedRefs, err := d.findPackedRefsInFile(f)
-	if err != nil {
-		return err
-	}
+func (d *DotGit) addRefsFromPackedRefs(refs *[]*plumbing.Reference, seen map[plumbing.ReferenceName]bool) (err error) {
+	return d.findPackedRefs(refsRecvFunc(refs, seen))
+}
 
-	for _, ref := range packedRefs {
-		if !seen[ref.Name()] {
-			*refs = append(*refs, ref)
-			seen[ref.Name()] = true
-		}
-	}
-	return nil
+func (d *DotGit) addRefsFromPackedRefsFile(refs *[]*plumbing.Reference, f billy.File, seen map[plumbing.ReferenceName]bool) (err error) {
+	return d.findPackedRefsInFile(f, refsRecvFunc(refs, seen))
 }
 
 func (d *DotGit) openAndLockPackedRefs(doCreate bool) (