protocol/packp: add reference update request encoder. (#147)

* add ReferenceUpdateRequest struct.
* add ReferenceUpdateRequest decoder.
* add ReferenceUpdateRequest encoder.

1 files changed, 67 insertions, 0 deletions

diff --git a/plumbing/protocol/packp/updreq_encode.go b/plumbing/protocol/packp/updreq_encode.go
new file mode 100644
index 0000000..b2b7944
--- /dev/null
+++ b/plumbing/protocol/packp/updreq_encode.go
@@ -0,0 +1,67 @@
+package packp
+
+import (
+	"fmt"
+	"io"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing/protocol/packp/capability"
+)
+
+var (
+	zeroHashString = plumbing.ZeroHash.String()
+)
+
+// Encode writes the ReferenceUpdateRequest encoding to the stream.
+func (r *ReferenceUpdateRequest) Encode(w io.Writer) error {
+	if err := r.validate(); err != nil {
+		return err
+	}
+
+	e := pktline.NewEncoder(w)
+
+	if err := r.encodeShallow(e, r.Shallow); err != nil {
+		return err
+	}
+
+	if err := r.encodeCommands(e, r.Commands, r.Capabilities); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (r *ReferenceUpdateRequest) encodeShallow(e *pktline.Encoder,
+	h *plumbing.Hash) error {
+
+	if h == nil {
+		return nil
+	}
+
+	objId := []byte(h.String())
+	return e.Encodef("%s%s", shallow, objId)
+}
+
+func (r *ReferenceUpdateRequest) encodeCommands(e *pktline.Encoder,
+	cmds []*Command, cap *capability.List) error {
+
+	if err := e.Encodef("%s\x00%s",
+		formatCommand(cmds[0]), cap.String()); err != nil {
+		return err
+	}
+
+	for _, cmd := range cmds[1:] {
+		if err := e.Encodef(formatCommand(cmd)); err != nil {
+			return err
+		}
+	}
+
+	return e.Flush()
+}
+
+func formatCommand(cmd *Command) string {
+	o := cmd.Old.String()
+	n := cmd.New.String()
+	return fmt.Sprintf("%s %s %s", o, n, cmd.Name)
+}