+type Hasher struct {
+ names []string
+ cmds []*exec.Cmd
+ ins []io.WriteCloser
+ outs []io.ReadCloser
+ wg sync.WaitGroup
+}
+
+func NewHasher(hashes string) *Hasher {
+ h := Hasher{}
+ for _, hc := range strings.Split(hashes, ",") {
+ cols := strings.SplitN(hc, ":", 2)
+ name, cmdline := cols[0], cols[1]
+ cmd := exec.Command(cmdline)
+ in, err := cmd.StdinPipe()
+ if err != nil {
+ log.Fatalln(err)
+ }
+ out, err := cmd.StdoutPipe()
+ if err != nil {
+ log.Fatalln(err)
+ }
+ if err = cmd.Start(); err != nil {
+ log.Fatalln(err)
+ }
+ h.names = append(h.names, name)
+ h.ins = append(h.ins, in)
+ h.outs = append(h.outs, out)
+ h.cmds = append(h.cmds, cmd)
+ }
+ return &h
+}
+
+func (h *Hasher) Write(p []byte) (n int, err error) {
+ h.wg.Add(len(h.names))
+ for _, in := range h.ins {
+ go func(in io.WriteCloser) {
+ if _, err := io.Copy(in, bytes.NewReader(p)); err != nil {
+ log.Fatalln(err)
+ }
+ h.wg.Done()
+ }(in)
+ }
+ h.wg.Wait()
+ return len(p), nil
+}
+
+func (h *Hasher) Sums() []meta4ra.Hash {
+ sums := make([]meta4ra.Hash, 0, len(h.names))
+ for i, name := range h.names {
+ if err := h.ins[i].Close(); err != nil {
+ log.Fatalln(err)
+ }
+ dgst, err := io.ReadAll(h.outs[i])
+ if err != nil {
+ log.Fatalln(err)
+ }
+ sums = append(sums, meta4ra.Hash{Type: name, Hash: string(dgst[:len(dgst)-1])})
+ if err = h.cmds[i].Wait(); err != nil {
+ log.Fatalln(err)
+ }
+ }
+ return sums
+}
+