Esempio n. 1
0
func (d *deltaeval) Copy(repo *libgit.Repository, src ObjectReference, offset, length uint64) {
	id, _ := libgit.NewId(src)
	_, _, r, err := repo.GetRawObject(id, false)
	if err != nil {
		panic(err)
	}
	defer r.Close()
	if offset > 0 {
		tmp := make([]byte, offset)
		n, err := io.ReadFull(r, tmp)
		if err != nil {
			panic(err)
		}
		if n == 0 || uint64(n) != offset {
			panic("Couldn't correctly read offset.")
		}

	}

	reading := make([]byte, length)
	n, err := io.ReadFull(r, reading)
	if uint64(n) != length || err != nil {
		panic("Error copying data")
	}
	d.value = append(d.value, reading...)
}
Esempio n. 2
0
// Calculate the final reslt of a REF_DELTA. This is largely
// based on the delta algorithm as described at:
// http://stefan.saasen.me/articles/git-clone-in-haskell-from-the-bottom-up/#pack_file_format
func calculateDelta(repo *libgit.Repository, reference ObjectReference, delta []byte) (PackEntryType, []byte) {
	deltaStream := bytes.NewBuffer(delta)

	// Read 2 variable length strings for the source and target buffer
	// length

	// read the source length, but we don't care. We just want to advance
	// the deltaStream pointer the proper amount.
	ReadVariable(deltaStream)
	// Read the target length so we know when we've finished processing
	// the delta stream.
	targetLength := ReadVariable(deltaStream)

	d := deltaeval{}
	for {
		d.DoInstruction(repo, deltaStream, reference, targetLength)
		if targetLength == uint64(len(d.value)) {
			break
		}
		if len(d.value) > int(targetLength) {
			panic("Read too much data from delta stream")
		}
	}
	// GetRawObject to find the underlying type of the original
	// reference
	id, err := libgit.NewId(reference)
	if err != nil {
		panic(err)
	}
	objt, _, _, err := repo.GetRawObject(id, true)
	if err != nil {
		panic(err)
	}
	switch objt {
	case libgit.ObjectCommit:
		return OBJ_COMMIT, d.value
	case libgit.ObjectTree:
		return OBJ_TREE, d.value
	case libgit.ObjectBlob:
		return OBJ_BLOB, d.value
	case libgit.ObjectTag:
		return OBJ_TAG, d.value
	}
	panic("Unhandle object type while calculating delta.")
	return 0, nil

}