6 files changed, 107 insertions, 13 deletions

diff --git a/plumbing/storer/object.go b/plumbing/storer/object.go
index bd34be8..29e0090 100644
--- a/plumbing/storer/object.go
+++ b/plumbing/storer/object.go
@@ -52,6 +52,11 @@ type EncodedObjectStorer interface {
 	LooseObjectTime(plumbing.Hash) (time.Time, error)
 	// DeleteLooseObject deletes a loose object if it exists.
 	DeleteLooseObject(plumbing.Hash) error
+	// ObjectPacks returns hashes of object packs if the underlying
+	// implementation has pack files.
+	ObjectPacks() ([]plumbing.Hash, error)
+	// DeleteObjectPackAndIndex deletes an object pack and the corresponding index file if they exist.
+	DeleteObjectPackAndIndex(plumbing.Hash) error
 }
 
 // DeltaObjectStorer is an EncodedObjectStorer that can return delta
diff --git a/plumbing/storer/object_test.go b/plumbing/storer/object_test.go
index f8b1f73..68e8e10 100644
--- a/plumbing/storer/object_test.go
+++ b/plumbing/storer/object_test.go
@@ -161,3 +161,7 @@ func (o *MockObjectStorage) LooseObjectTime(plumbing.Hash) (time.Time, error) {
 func (o *MockObjectStorage) DeleteLooseObject(plumbing.Hash) error {
 	return plumbing.ErrObjectNotFound
 }
+
+func (o *MockObjectStorage) ObjectPacks() ([]plumbing.Hash, error) {
+	return nil, nil
+}
diff --git a/repository.go b/repository.go
index b159ff0..51cd077 100644
--- a/repository.go
+++ b/repository.go
@@ -12,6 +12,7 @@ import (
 	"gopkg.in/src-d/go-git.v4/config"
 	"gopkg.in/src-d/go-git.v4/internal/revision"
 	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packfile"
 	"gopkg.in/src-d/go-git.v4/plumbing/object"
 	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"gopkg.in/src-d/go-git.v4/storage"
@@ -1011,3 +1012,64 @@ func (r *Repository) ResolveRevision(rev plumbing.Revision) (*plumbing.Hash, err
 
 	return &commit.Hash, nil
 }
+
+func (r *Repository) RepackObjects() (err error) {
+	// Get the existing object packs.
+	hs, err := r.Storer.ObjectPacks()
+	if err != nil {
+		return err
+	}
+
+	// Create a new pack.
+	nh, err := r.createNewObjectPack()
+	if err != nil {
+		return err
+	}
+
+	// Delete old packs.
+	for _, h := range hs {
+		// Skip if new hash is the same as an old one.
+		if h == nh {
+			continue
+		}
+		err = r.Storer.DeleteObjectPackAndIndex(h)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// createNewObjectPack is a helper for RepackObjects taking care
+// of creating a new pack. It is used so the the PackfileWriter
+// deferred close has the right scope.
+func (r *Repository) createNewObjectPack() (h plumbing.Hash, err error) {
+	pfw, ok := r.Storer.(storer.PackfileWriter)
+	if !ok {
+		return h, fmt.Errorf("Repository storer is not a storer.PackfileWriter")
+	}
+	wc, err := pfw.PackfileWriter(nil)
+	if err != nil {
+		return h, err
+	}
+	defer ioutil.CheckClose(wc, &err)
+	var objs []plumbing.Hash
+	iter, err := r.Storer.IterEncodedObjects(plumbing.AnyObject)
+	if err != nil {
+		return h, err
+	}
+	err = iter.ForEach(func(obj plumbing.EncodedObject) error {
+		objs = append(objs, obj.Hash())
+		return nil
+	})
+	if err != nil {
+		return h, err
+	}
+	enc := packfile.NewEncoder(wc, r.Storer, false)
+	h, err = enc.Encode(objs, 10, nil)
+	if err != nil {
+		return h, err
+	}
+	return h, err
+}
diff --git a/storage/filesystem/internal/dotgit/dotgit.go b/storage/filesystem/internal/dotgit/dotgit.go
index 83fe159..09688c1 100644
--- a/storage/filesystem/internal/dotgit/dotgit.go
+++ b/storage/filesystem/internal/dotgit/dotgit.go
@@ -166,11 +166,12 @@ func (d *DotGit) ObjectPacks() ([]plumbing.Hash, error) {
 	return packs, nil
 }
 
-// ObjectPack returns a fs.File of the given packfile
-func (d *DotGit) ObjectPack(hash plumbing.Hash) (billy.File, error) {
-	file := d.fs.Join(objectsPath, packPath, fmt.Sprintf("pack-%s.pack", hash.String()))
+func (d *DotGit) objectPackPath(hash plumbing.Hash, extension string) string {
+	return d.fs.Join(objectsPath, packPath, fmt.Sprintf("pack-%s.%s", hash.String(), extension))
+}
 
-	pack, err := d.fs.Open(file)
+func (d *DotGit) objectPackOpen(hash plumbing.Hash, extension string) (billy.File, error) {
+	pack, err := d.fs.Open(d.objectPackPath(hash, extension))
 	if err != nil {
 		if os.IsNotExist(err) {
 			return nil, ErrPackfileNotFound
@@ -182,19 +183,26 @@ func (d *DotGit) ObjectPack(hash plumbing.Hash) (billy.File, error) {
 	return pack, nil
 }
 
+// ObjectPack returns a fs.File of the given packfile
+func (d *DotGit) ObjectPack(hash plumbing.Hash) (billy.File, error) {
+	return d.objectPackOpen(hash, `pack`)
+}
+
 // ObjectPackIdx returns a fs.File of the index file for a given packfile
 func (d *DotGit) ObjectPackIdx(hash plumbing.Hash) (billy.File, error) {
-	file := d.fs.Join(objectsPath, packPath, fmt.Sprintf("pack-%s.idx", hash.String()))
-	idx, err := d.fs.Open(file)
-	if err != nil {
-		if os.IsNotExist(err) {
-			return nil, ErrPackfileNotFound
-		}
+	return d.objectPackOpen(hash, `idx`)
+}
 
-		return nil, err
+func (d *DotGit) DeleteObjectPackAndIndex(hash plumbing.Hash) error {
+	err := d.fs.Remove(d.objectPackPath(hash, `pack`))
+	if err != nil {
+		return err
 	}
-
-	return idx, nil
+	err = d.fs.Remove(d.objectPackPath(hash, `idx`))
+	if err != nil {
+		return err
+	}
+	return nil
 }
 
 // NewObject return a writer for a new object file.
diff --git a/storage/filesystem/object.go b/storage/filesystem/object.go
index 9b2790f..f235204 100644
--- a/storage/filesystem/object.go
+++ b/storage/filesystem/object.go
@@ -503,3 +503,11 @@ func (s *ObjectStorage) LooseObjectTime(hash plumbing.Hash) (time.Time, error) {
 func (s *ObjectStorage) DeleteLooseObject(hash plumbing.Hash) error {
 	return s.dir.ObjectDelete(hash)
 }
+
+func (s *ObjectStorage) ObjectPacks() ([]plumbing.Hash, error) {
+	return s.dir.ObjectPacks()
+}
+
+func (s *ObjectStorage) DeleteObjectPackAndIndex(h plumbing.Hash) error {
+	return s.dir.DeleteObjectPackAndIndex(h)
+}
diff --git a/storage/memory/storage.go b/storage/memory/storage.go
index bfcad34..5049036 100644
--- a/storage/memory/storage.go
+++ b/storage/memory/storage.go
@@ -170,6 +170,13 @@ func (o *ObjectStorage) ForEachObjectHash(fun func(plumbing.Hash) error) error {
 	return nil
 }
 
+func (o *ObjectStorage) ObjectPacks() ([]plumbing.Hash, error) {
+	return nil, nil
+}
+func (o *ObjectStorage) DeleteObjectPackAndIndex(plumbing.Hash) error {
+	return errNotSupported
+}
+
 var errNotSupported = fmt.Errorf("Not supported")
 
 func (s *ObjectStorage) LooseObjectTime(hash plumbing.Hash) (time.Time, error) {