func renderSumForHeader(v Version, h *tar.Header, data []byte) (string, error) { buf := bytes.NewBuffer(nil) // first build our test tar tw := tar.NewWriter(buf) if err := tw.WriteHeader(h); err != nil { return "", err } if _, err := tw.Write(data); err != nil { return "", err } tw.Close() ts, err := newTarSum(buf, true, v) if err != nil { return "", err } tr := tar.NewReader(ts) for { hdr, err := tr.Next() if hdr == nil || err == io.EOF { break } if err != nil { return "", err } if _, err = io.Copy(ioutil.Discard, tr); err != nil { return "", err } } return ts.Sum(nil), nil }
func (ts *tarSum) initTarSum() error { ts.bufTar = bytes.NewBuffer([]byte{}) ts.bufWriter = bytes.NewBuffer([]byte{}) ts.tarR = tar.NewReader(ts.Reader) ts.tarW = tar.NewWriter(ts.bufTar) if !ts.DisableCompression { ts.writer = gzip.NewWriter(ts.bufWriter) } else { ts.writer = &nopCloseFlusher{Writer: ts.bufWriter} } if ts.th == nil { ts.th = defaultTHash } ts.h = ts.th.Hash() ts.h.Reset() ts.first = true ts.sums = fileInfoSums{} return nil }