Function splitBatchCatFileOutput

repository/git.go:745–791

splitBatchCatFileOutput parses the output of a 'git cat-file --batch=...' command. The output is expected to be formatted as a series of entries, with each entry consisting of: 1. The SHA1 hash of the git object being output, followed by a newline. 2. The size of the object's contents in bytes, fol

(out *bytes.Buffer)

// To generate this format, make sure that the 'git cat-file' command includes
// the argument '--batch=%(objectname)\n%(objectsize)'.
func splitBatchCatFileOutput(out *bytes.Buffer) (map[string][]byte, error) {
	contentsMap := make(map[string][]byte)
	reader := bufio.NewReader(out)
	for {
		nameLine, err := reader.ReadString(byte('\n'))
		if strings.HasSuffix(nameLine, "\n") {
			nameLine = strings.TrimSuffix(nameLine, "\n")
		}
		if err == io.EOF {
			return contentsMap, nil
		}
		if err != nil {
			return nil, fmt.Errorf("Failure while reading the next object name: %v", err)
		}
		sizeLine, err := reader.ReadString(byte('\n'))
		if strings.HasSuffix(sizeLine, "\n") {
			sizeLine = strings.TrimSuffix(sizeLine, "\n")
		}
		if err != nil {
			return nil, fmt.Errorf("Failure while reading the next object size: %q - %v", nameLine, err)
		}
		size, err := strconv.Atoi(sizeLine)
		if err != nil {
			return nil, fmt.Errorf("Failure while parsing the next object size: %q - %v", nameLine, err)
		}
		contentBytes := make([]byte, size, size)
		readDest := contentBytes
		len := 0
		err = nil
		for err == nil && len < size {
			nextLen := 0
			nextLen, err = reader.Read(readDest)
			len += nextLen
			readDest = contentBytes[len:]
		}
		contentsMap[nameLine] = contentBytes
		if err == io.EOF {
			return contentsMap, nil
		}
		if err != nil {
			return nil, err
		}
		for bs, err := reader.Peek(1); err == nil && bs[0] == byte('\n'); bs, err = reader.Peek(1) {
			reader.ReadByte()
		}
	}
}

// notesMapping represents the association between a git object and the notes for that object.
type notesMapping struct {