diff options
| -rw-r--r-- | plumbing/format/packfile/packfile.go | 84 |
1 files changed, 61 insertions, 23 deletions
diff --git a/plumbing/format/packfile/packfile.go b/plumbing/format/packfile/packfile.go index 69b6e85..4fa654c 100644 --- a/plumbing/format/packfile/packfile.go +++ b/plumbing/format/packfile/packfile.go @@ -76,10 +76,10 @@ func (p *Packfile) Get(h plumbing.Hash) (plumbing.EncodedObject, error) { return nil, err } - return p.GetByOffset(offset) + return p.objectAtOffset(offset, h) } -// GetByOffset retrieves the encoded object from the packfile with the given +// GetByOffset retrieves the encoded object from the packfile at the given // offset. func (p *Packfile) GetByOffset(o int64) (plumbing.EncodedObject, error) { hash, err := p.FindHash(o) @@ -89,7 +89,7 @@ func (p *Packfile) GetByOffset(o int64) (plumbing.EncodedObject, error) { } } - return p.objectAtOffset(o) + return p.objectAtOffset(o, hash) } // GetSizeByOffset retrieves the size of the encoded object from the @@ -122,6 +122,13 @@ func (p *Packfile) nextObjectHeader() (*ObjectHeader, error) { return h, err } +func (p *Packfile) getDeltaObjectSize(buf *bytes.Buffer) int64 { + delta := buf.Bytes() + _, delta = decodeLEB128(delta) // skip src size + sz, _ := decodeLEB128(delta) + return int64(sz) +} + func (p *Packfile) getObjectSize(h *ObjectHeader) (int64, error) { switch h.Type { case plumbing.CommitObject, plumbing.TreeObject, plumbing.BlobObject, plumbing.TagObject: @@ -135,10 +142,7 @@ func (p *Packfile) getObjectSize(h *ObjectHeader) (int64, error) { return 0, err } - delta := buf.Bytes() - _, delta = decodeLEB128(delta) // skip src size - sz, _ := decodeLEB128(delta) - return int64(sz), nil + return p.getDeltaObjectSize(buf), nil default: return 0, ErrInvalidObject.AddDetails("type %q", h.Type) } @@ -179,7 +183,7 @@ func (p *Packfile) getObjectType(h *ObjectHeader) (typ plumbing.ObjectType, err return } -func (p *Packfile) objectAtOffset(offset int64) (plumbing.EncodedObject, error) { +func (p *Packfile) objectAtOffset(offset int64, hash plumbing.Hash) (plumbing.EncodedObject, error) { h, err := p.objectHeaderAtOffset(offset) if err != nil { if err == io.EOF || isInvalid(err) { @@ -194,21 +198,42 @@ func (p *Packfile) objectAtOffset(offset int64) (plumbing.EncodedObject, error) return p.getNextObject(h) } - // If the object is not a delta and it's small enough then read it - // completely into memory now since it is already read from disk - // into buffer anyway. - if h.Length <= smallObjectThreshold && h.Type != plumbing.OFSDeltaObject && h.Type != plumbing.REFDeltaObject { - return p.getNextObject(h) - } + // If the object is small enough then read it completely into memory now since + // it is already read from disk into buffer anyway. For delta objects we want + // to perform the optimization too, but we have to be careful about applying + // small deltas on big objects. + var size int64 + if h.Length <= smallObjectThreshold { + if h.Type != plumbing.OFSDeltaObject && h.Type != plumbing.REFDeltaObject { + return p.getNextObject(h) + } - hash, err := p.FindHash(h.Offset) - if err != nil { - return nil, err - } + // For delta objects we read the delta data and create a special object + // that will hold them in memory and resolve them lazily to the referenced + // object. + buf := bufPool.Get().(*bytes.Buffer) + buf.Reset() + if _, _, err := p.s.NextObject(buf); err != nil { + return nil, err + } + defer bufPool.Put(buf) - size, err := p.getObjectSize(h) - if err != nil { - return nil, err + size = p.getDeltaObjectSize(buf) + if size <= smallObjectThreshold { + var obj = new(plumbing.MemoryObject) + obj.SetSize(size) + if h.Type == plumbing.REFDeltaObject { + err = p.fillREFDeltaObjectContentWithBuffer(obj, h.Reference, buf) + } else { + err = p.fillOFSDeltaObjectContentWithBuffer(obj, h.OffsetReference, buf) + } + return obj, nil + } + } else { + size, err = p.getObjectSize(h) + if err != nil { + return nil, err + } } typ, err := p.getObjectType(h) @@ -300,6 +325,13 @@ func (p *Packfile) fillREFDeltaObjectContent(obj plumbing.EncodedObject, ref plu if err != nil { return err } + defer bufPool.Put(buf) + + return p.fillREFDeltaObjectContentWithBuffer(obj, ref, buf) +} + +func (p *Packfile) fillREFDeltaObjectContentWithBuffer(obj plumbing.EncodedObject, ref plumbing.Hash, buf *bytes.Buffer) error { + var err error base, ok := p.cacheGet(ref) if !ok { @@ -312,18 +344,24 @@ func (p *Packfile) fillREFDeltaObjectContent(obj plumbing.EncodedObject, ref plu obj.SetType(base.Type()) err = ApplyDelta(obj, base, buf.Bytes()) p.cachePut(obj) - bufPool.Put(buf) return err } func (p *Packfile) fillOFSDeltaObjectContent(obj plumbing.EncodedObject, offset int64) error { buf := bytes.NewBuffer(nil) + buf.Reset() _, _, err := p.s.NextObject(buf) if err != nil { return err } + defer bufPool.Put(buf) + return p.fillOFSDeltaObjectContentWithBuffer(obj, offset, buf) +} + +func (p *Packfile) fillOFSDeltaObjectContentWithBuffer(obj plumbing.EncodedObject, offset int64, buf *bytes.Buffer) error { + var err error var base plumbing.EncodedObject var ok bool hash, err := p.FindHash(offset) @@ -332,7 +370,7 @@ func (p *Packfile) fillOFSDeltaObjectContent(obj plumbing.EncodedObject, offset } if !ok { - base, err = p.GetByOffset(offset) + base, err = p.objectAtOffset(offset, hash) if err != nil { return err } |