server: add git server implementation (#190)

* server: add generic server implementation (transport-independent),
  both for git-upload-pack and git-receive-pack.
* server: move internal functions to internal/common.
* cli: add git-receive-pack and git-upload-pack implementations.
* format/packfile: add UpdateObjectStorage function, extracted from
  Remote.
* transport: implement tranport RPC-like, only with git-upload-pack and
  git-receive-pack methods. Client renamed to Transport.
* storer: add storer.Storer interface.
* protocol/packp: add UploadPackResponse constructor with packfile.
* protocol/packp: fix UploadPackResponse encoding, add tests.
* protocol/packp/capability: implement All.

1 files changed, 14 insertions, 0 deletions

diff --git a/plumbing/protocol/packp/srvresp.go b/plumbing/protocol/packp/srvresp.go
index 3284fa2..d41b50d 100644
--- a/plumbing/protocol/packp/srvresp.go
+++ b/plumbing/protocol/packp/srvresp.go
@@ -68,3 +68,17 @@ func (r *ServerResponse) decodeACKLine(line []byte) error {
 	r.ACKs = append(r.ACKs, h)
 	return nil
 }
+
+// Encode encodes the ServerResponse into a writer.
+func (r *ServerResponse) Encode(w io.Writer) error {
+	if len(r.ACKs) > 1 {
+		return errors.New("multi_ack and multi_ack_detailed are not supported")
+	}
+
+	e := pktline.NewEncoder(w)
+	if len(r.ACKs) == 0 {
+		return e.Encodef("%s\n", nak)
+	}
+
+	return e.Encodef("%s %s\n", ack, r.ACKs[0].String())
+}