feat(dir2config): defaults

vendor/gopkg.in/src-d/go-git.v4/plumbing/protocol/packp/shallowupd.go

@@ -0,0 +1,92 @@
+package packp
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/pktline"
+)
+
+const (
+	shallowLineLen   = 48
+	unshallowLineLen = 50
+)
+
+type ShallowUpdate struct {
+	Shallows   []plumbing.Hash
+	Unshallows []plumbing.Hash
+}
+
+func (r *ShallowUpdate) Decode(reader io.Reader) error {
+	s := pktline.NewScanner(reader)
+
+	for s.Scan() {
+		line := s.Bytes()
+		line = bytes.TrimSpace(line)
+
+		var err error
+		switch {
+		case bytes.HasPrefix(line, shallow):
+			err = r.decodeShallowLine(line)
+		case bytes.HasPrefix(line, unshallow):
+			err = r.decodeUnshallowLine(line)
+		case bytes.Equal(line, pktline.Flush):
+			return nil
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+
+	return s.Err()
+}
+
+func (r *ShallowUpdate) decodeShallowLine(line []byte) error {
+	hash, err := r.decodeLine(line, shallow, shallowLineLen)
+	if err != nil {
+		return err
+	}
+
+	r.Shallows = append(r.Shallows, hash)
+	return nil
+}
+
+func (r *ShallowUpdate) decodeUnshallowLine(line []byte) error {
+	hash, err := r.decodeLine(line, unshallow, unshallowLineLen)
+	if err != nil {
+		return err
+	}
+
+	r.Unshallows = append(r.Unshallows, hash)
+	return nil
+}
+
+func (r *ShallowUpdate) decodeLine(line, prefix []byte, expLen int) (plumbing.Hash, error) {
+	if len(line) != expLen {
+		return plumbing.ZeroHash, fmt.Errorf("malformed %s%q", prefix, line)
+	}
+
+	raw := string(line[expLen-40 : expLen])
+	return plumbing.NewHash(raw), nil
+}
+
+func (r *ShallowUpdate) Encode(w io.Writer) error {
+	e := pktline.NewEncoder(w)
+
+	for _, h := range r.Shallows {
+		if err := e.Encodef("%s%s\n", shallow, h.String()); err != nil {
+			return err
+		}
+	}
+
+	for _, h := range r.Unshallows {
+		if err := e.Encodef("%s%s\n", unshallow, h.String()); err != nil {
+			return err
+		}
+	}
+
+	return e.Flush()
+}