From 9f752b8306b95c57bd267bae47f2c8462551331b Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Thu, 25 Aug 2016 21:08:16 +0200
Subject: [PATCH] Rework function for listing packs

---
 src/restic/checker/checker.go       |  4 ++--
 src/restic/pack/pack.go             | 23 +++--------------------
 src/restic/pack/pack_test.go        |  6 +++---
 src/restic/repository/repack.go     |  6 +++---
 src/restic/repository/repository.go |  4 ++--
 5 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/src/restic/checker/checker.go b/src/restic/checker/checker.go
index bcfa56a04..ff07b7539 100644
--- a/src/restic/checker/checker.go
+++ b/src/restic/checker/checker.go
@@ -676,13 +676,13 @@ func checkPack(r *repository.Repository, id backend.ID) error {
 		return fmt.Errorf("Pack ID does not match, want %v, got %v", id.Str(), hash.Str())
 	}
 
-	unpacker, err := pack.NewUnpacker(r.Key(), pack.BufferLoader(buf))
+	blobs, err := pack.List(r.Key(), pack.BufferLoader(buf))
 	if err != nil {
 		return err
 	}
 
 	var errs []error
-	for i, blob := range unpacker.Entries {
+	for i, blob := range blobs {
 		debug.Log("Checker.checkPack", "  check blob %d: %v", i, blob.ID.Str())
 
 		plainBuf := make([]byte, blob.Length)
diff --git a/src/restic/pack/pack.go b/src/restic/pack/pack.go
index 04b752123..e60c14f76 100644
--- a/src/restic/pack/pack.go
+++ b/src/restic/pack/pack.go
@@ -228,22 +228,13 @@ func (p *Packer) String() string {
 	return fmt.Sprintf("<Packer %d blobs, %d bytes>", len(p.blobs), p.bytes)
 }
 
-// Unpacker is used to read individual blobs from a pack.
-type Unpacker struct {
-	rd      io.ReadSeeker
-	Entries []Blob
-	k       *crypto.Key
-}
-
 const (
 	preloadHeaderSize = 2048
 	maxHeaderSize     = 16 * 1024 * 1024
 )
 
-// NewUnpacker returns a pointer to Unpacker which can be used to read
-// individual Blobs from a pack.
-func NewUnpacker(k *crypto.Key, ldr Loader) (*Unpacker, error) {
-	var err error
+// List returns the list of entries found in a pack file.
+func List(k *crypto.Key, ldr Loader) (entries []Blob, err error) {
 
 	// read the last 2048 byte, this will mostly be enough for the header, so
 	// we do not need another round trip.
@@ -294,8 +285,6 @@ func NewUnpacker(k *crypto.Key, ldr Loader) (*Unpacker, error) {
 
 	rd := bytes.NewReader(hdr)
 
-	var entries []Blob
-
 	pos := uint(0)
 	for {
 		e := headerEntry{}
@@ -328,11 +317,5 @@ func NewUnpacker(k *crypto.Key, ldr Loader) (*Unpacker, error) {
 		pos += uint(e.Length)
 	}
 
-	up := &Unpacker{
-		rd:      rd,
-		k:       k,
-		Entries: entries,
-	}
-
-	return up, nil
+	return entries, nil
 }
diff --git a/src/restic/pack/pack_test.go b/src/restic/pack/pack_test.go
index e13c9884a..48870b9e6 100644
--- a/src/restic/pack/pack_test.go
+++ b/src/restic/pack/pack_test.go
@@ -63,13 +63,13 @@ func verifyBlobs(t testing.TB, bufs []Buf, k *crypto.Key, ldr pack.Loader, packS
 	Equals(t, uint(written), packSize)
 
 	// read and parse it again
-	np, err := pack.NewUnpacker(k, ldr)
+	entries, err := pack.List(k, ldr)
 	OK(t, err)
-	Equals(t, len(np.Entries), len(bufs))
+	Equals(t, len(entries), len(bufs))
 
 	var buf []byte
 	for i, b := range bufs {
-		e := np.Entries[i]
+		e := entries[i]
 		Equals(t, b.id, e.ID)
 
 		if len(buf) < int(e.Length) {
diff --git a/src/restic/repository/repack.go b/src/restic/repository/repack.go
index 0498164a4..a72b4e351 100644
--- a/src/restic/repository/repack.go
+++ b/src/restic/repository/repack.go
@@ -32,14 +32,14 @@ func Repack(repo *Repository, packs backend.IDSet, keepBlobs pack.BlobSet) (err
 
 		debug.Log("Repack", "pack %v loaded (%d bytes)", packID.Str(), len(buf))
 
-		unpck, err := pack.NewUnpacker(repo.Key(), pack.BufferLoader(buf))
+		blobs, err := pack.List(repo.Key(), pack.BufferLoader(buf))
 		if err != nil {
 			return err
 		}
 
-		debug.Log("Repack", "processing pack %v, blobs: %v", packID.Str(), len(unpck.Entries))
+		debug.Log("Repack", "processing pack %v, blobs: %v", packID.Str(), len(blobs))
 		var plaintext []byte
-		for _, entry := range unpck.Entries {
+		for _, entry := range blobs {
 			h := pack.Handle{ID: entry.ID, Type: entry.Type}
 			if !keepBlobs.Has(h) {
 				continue
diff --git a/src/restic/repository/repository.go b/src/restic/repository/repository.go
index 9c8aea25b..9ef948793 100644
--- a/src/restic/repository/repository.go
+++ b/src/restic/repository/repository.go
@@ -556,12 +556,12 @@ func (r *Repository) ListPack(id backend.ID) ([]pack.Blob, int64, error) {
 
 	ldr := pack.BackendLoader{Backend: r.Backend(), Handle: h}
 
-	unpacker, err := pack.NewUnpacker(r.Key(), ldr)
+	blobs, err := pack.List(r.Key(), ldr)
 	if err != nil {
 		return nil, 0, err
 	}
 
-	return unpacker.Entries, blobInfo.Size, nil
+	return blobs, blobInfo.Size, nil
 }
 
 // Delete calls backend.Delete() if implemented, and returns an error