diff options
| -rw-r--r-- | plumbing/format/packfile/patch_delta.go | 45 |
1 files changed, 30 insertions, 15 deletions
diff --git a/plumbing/format/packfile/patch_delta.go b/plumbing/format/packfile/patch_delta.go index 7840f17..e1a5141 100644 --- a/plumbing/format/packfile/patch_delta.go +++ b/plumbing/format/packfile/patch_delta.go @@ -3,6 +3,7 @@ package packfile import ( "bytes" "errors" + "io" "gopkg.in/src-d/go-git.v4/plumbing" ) @@ -35,14 +36,20 @@ func ApplyDelta(target, base plumbing.EncodedObject, delta []byte) error { } src := buf.Bytes() - dst, err := PatchDelta(src, delta) + dst := bufPool.Get().(*bytes.Buffer) + defer bufPool.Put(dst) + dst.Reset() + err = patchDelta(dst, src, delta) if err != nil { return err } - target.SetSize(int64(len(dst))) - _, err = w.Write(dst) + target.SetSize(int64(dst.Len())) + + b := byteSlicePool.Get().([]byte) + _, err = io.CopyBuffer(w, dst, b) + byteSlicePool.Put(b) return err } @@ -55,23 +62,31 @@ var ( // An error will be returned if delta is corrupted (ErrDeltaLen) or an action command // is not copy from source or copy from delta (ErrDeltaCmd). func PatchDelta(src, delta []byte) ([]byte, error) { + b := &bytes.Buffer{} + if err := patchDelta(b, src, delta); err != nil { + return nil, err + } + return b.Bytes(), nil +} + +func patchDelta(dst *bytes.Buffer, src, delta []byte) error { if len(delta) < deltaSizeMin { - return nil, ErrInvalidDelta + return ErrInvalidDelta } srcSz, delta := decodeLEB128(delta) if srcSz != uint(len(src)) { - return nil, ErrInvalidDelta + return ErrInvalidDelta } targetSz, delta := decodeLEB128(delta) remainingTargetSz := targetSz var cmd byte - dest := make([]byte, 0, targetSz) + dst.Grow(int(targetSz)) for { if len(delta) == 0 { - return nil, ErrInvalidDelta + return ErrInvalidDelta } cmd = delta[0] @@ -81,35 +96,35 @@ func PatchDelta(src, delta []byte) ([]byte, error) { var err error offset, delta, err = decodeOffset(cmd, delta) if err != nil { - return nil, err + return err } sz, delta, err = decodeSize(cmd, delta) if err != nil { - return nil, err + return err } if invalidSize(sz, targetSz) || invalidOffsetSize(offset, sz, srcSz) { break } - dest = append(dest, src[offset:offset+sz]...) + dst.Write(src[offset:offset+sz]) remainingTargetSz -= sz } else if isCopyFromDelta(cmd) { sz := uint(cmd) // cmd is the size itself if invalidSize(sz, targetSz) { - return nil, ErrInvalidDelta + return ErrInvalidDelta } if uint(len(delta)) < sz { - return nil, ErrInvalidDelta + return ErrInvalidDelta } - dest = append(dest, delta[0:sz]...) + dst.Write(delta[0:sz]) remainingTargetSz -= sz delta = delta[sz:] } else { - return nil, ErrDeltaCmd + return ErrDeltaCmd } if remainingTargetSz <= 0 { @@ -117,7 +132,7 @@ func PatchDelta(src, delta []byte) ([]byte, error) { } } - return dest, nil + return nil } // Decodes a number encoded as an unsigned LEB128 at the start of some |