Return hdrSize in ListPack

internal/checker/checker.go

@@ -749,7 +749,7 @@ func checkPack(ctx context.Context, r restic.Repository, id restic.ID, size int6
 		return errors.Errorf("Pack size does not match, want %v, got %v", size, realSize)
 	}
 
-	blobs, err := pack.List(r.Key(), packfile, size)
+	blobs, _, err := pack.List(r.Key(), packfile, size)
 	if err != nil {
 		return err
 	}

internal/pack/pack.go

@@ -252,21 +252,24 @@ func (e InvalidFileError) Error() string {
 	return e.Message
 }
 
-// List returns the list of entries found in a pack file.
-func List(k *crypto.Key, rd io.ReaderAt, size int64) (entries []restic.Blob, err error) {
+// List returns the list of entries found in a pack file and the length of the
+// header (including header size and crypto overhead)
+func List(k *crypto.Key, rd io.ReaderAt, size int64) (entries []restic.Blob, hdrSize uint32, err error) {
 	buf, err := readHeader(rd, size)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 
 	if len(buf) < k.NonceSize()+k.Overhead() {
-		return nil, errors.New("invalid header, too small")
+		return nil, 0, errors.New("invalid header, too small")
 	}
 
+	hdrSize = headerLengthSize + uint32(len(buf))
+
 	nonce, buf := buf[:k.NonceSize()], buf[k.NonceSize():]
 	buf, err = k.Open(buf[:0], nonce, buf, nil)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 
 	entries = make([]restic.Blob, 0, uint(len(buf))/entrySize)
@@ -275,7 +278,7 @@ func List(k *crypto.Key, rd io.ReaderAt, size int64) (entries []restic.Blob, err
 	for len(buf) > 0 {
 		entry, err := parseHeaderEntry(buf)
 		if err != nil {
-			return nil, err
+			return nil, 0, err
 		}
 		entry.Offset = pos
 
@@ -284,7 +287,7 @@ func List(k *crypto.Key, rd io.ReaderAt, size int64) (entries []restic.Blob, err
 		buf = buf[entrySize:]
 	}
 
-	return entries, nil
+	return entries, hdrSize, nil
 }
 
 // PackedSizeOfBlob returns the size a blob actually uses when saved in a pack

internal/pack/pack_test.go

@@ -53,19 +53,18 @@ func verifyBlobs(t testing.TB, bufs []Buf, k *crypto.Key, rd io.ReaderAt, packSi
 	for _, buf := range bufs {
 		written += len(buf.data)
 	}
-	// header length
-	written += binary.Size(uint32(0))
-	// header + header crypto
-	headerSize := len(bufs) * (binary.Size(restic.BlobType(0)) + binary.Size(uint32(0)) + len(restic.ID{}))
-	written += restic.CiphertextLength(headerSize)
+	// header length + header + header crypto
+	headerSize := binary.Size(uint32(0)) + restic.CiphertextLength(len(bufs)*int(pack.EntrySize))
+	written += headerSize
 
 	// check length
 	rtest.Equals(t, uint(written), packSize)
 
 	// read and parse it again
-	entries, err := pack.List(k, rd, int64(packSize))
+	entries, hdrSize, err := pack.List(k, rd, int64(packSize))
 	rtest.OK(t, err)
 	rtest.Equals(t, len(entries), len(bufs))
+	rtest.Equals(t, headerSize, int(hdrSize))
 
 	var buf []byte
 	for i, b := range bufs {

internal/repository/repack.go

@@ -92,7 +92,7 @@ func Repack(ctx context.Context, repo restic.Repository, packs restic.IDSet, kee
 		for job := range processQueue {
 			tempfile, packID, packLength := job.tempfile, job.hash, job.packLength
 
-			blobs, err := pack.List(repo.Key(), tempfile, packLength)
+			blobs, _, err := pack.List(repo.Key(), tempfile, packLength)
 			if err != nil {
 				return err
 			}

internal/repository/repository.go

@@ -740,16 +740,11 @@ func (r *Repository) List(ctx context.Context, t restic.FileType, fn func(restic
 }
 
 // ListPack returns the list of blobs saved in the pack id and the length of
-// the file as stored in the backend.
-func (r *Repository) ListPack(ctx context.Context, id restic.ID, size int64) ([]restic.Blob, int64, error) {
+// the the pack header.
+func (r *Repository) ListPack(ctx context.Context, id restic.ID, size int64) ([]restic.Blob, uint32, error) {
 	h := restic.Handle{Type: restic.PackFile, Name: id.String()}
 
-	blobs, err := pack.List(r.Key(), restic.ReaderAt(ctx, r.Backend(), h), size)
-	if err != nil {
-		return nil, 0, err
-	}
-
-	return blobs, size, nil
+	return pack.List(r.Key(), restic.ReaderAt(ctx, r.Backend(), h), size)
 }
 
 // Delete calls backend.Delete() if implemented, and returns an error

internal/restic/repository.go

@@ -32,7 +32,10 @@ type Repository interface {
 	//
 	// The function fn is called in the same Goroutine List() was called from.
 	List(ctx context.Context, t FileType, fn func(ID, int64) error) error
-	ListPack(context.Context, ID, int64) ([]Blob, int64, error)
+
+	// ListPack returns the list of blobs saved in the pack id and the length of
+	// the the pack header.
+	ListPack(context.Context, ID, int64) ([]Blob, uint32, error)
 
 	Flush(context.Context) error