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.

8 files changed, 215 insertions, 2 deletions

diff --git a/plumbing/protocol/packp/capability/list.go b/plumbing/protocol/packp/capability/list.go
index 2847580..69fdb51 100644
--- a/plumbing/protocol/packp/capability/list.go
+++ b/plumbing/protocol/packp/capability/list.go
@@ -167,6 +167,16 @@ func (l *List) Delete(capability Capability) {
 	}
 }
 
+// All returns a slice with all defined capabilities.
+func (l *List) All() []Capability {
+	var cs []Capability
+	for _, key := range l.sort {
+		cs = append(cs, Capability(key))
+	}
+
+	return cs
+}
+
 // String generates the capabilities strings, the capabilities are sorted in
 // insertion order
 func (l *List) String() string {
diff --git a/plumbing/protocol/packp/capability/list_test.go b/plumbing/protocol/packp/capability/list_test.go
index 42f0179..0a0ad26 100644
--- a/plumbing/protocol/packp/capability/list_test.go
+++ b/plumbing/protocol/packp/capability/list_test.go
@@ -171,3 +171,14 @@ func (s *SuiteCapabilities) TestAddErrMultipleArgumentsAtTheSameTime(c *check.C)
 	err := cap.Add(Agent, "foo", "bar")
 	c.Assert(err, check.Equals, ErrMultipleArguments)
 }
+
+func (s *SuiteCapabilities) TestAll(c *check.C) {
+	cap := NewList()
+	c.Assert(NewList().All(), check.IsNil)
+
+	cap.Add(Agent, "foo")
+	c.Assert(cap.All(), check.DeepEquals, []Capability{Agent})
+
+	cap.Add(OFSDelta)
+	c.Assert(cap.All(), check.DeepEquals, []Capability{Agent, OFSDelta})
+}
diff --git a/plumbing/protocol/packp/shallowupd.go b/plumbing/protocol/packp/shallowupd.go
index 89063de..40f58e8 100644
--- a/plumbing/protocol/packp/shallowupd.go
+++ b/plumbing/protocol/packp/shallowupd.go
@@ -24,6 +24,7 @@ func (r *ShallowUpdate) Decode(reader io.Reader) error {
 
 	for s.Scan() {
 		line := s.Bytes()
+		line = bytes.TrimSpace(line)
 
 		var err error
 		switch {
@@ -71,3 +72,21 @@ func (r *ShallowUpdate) decodeLine(line, prefix []byte, expLen int) (plumbing.Ha
 	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()
+}
diff --git a/plumbing/protocol/packp/shallowupd_test.go b/plumbing/protocol/packp/shallowupd_test.go
index d64fb5d..97a13fc 100644
--- a/plumbing/protocol/packp/shallowupd_test.go
+++ b/plumbing/protocol/packp/shallowupd_test.go
@@ -12,6 +12,26 @@ type ShallowUpdateSuite struct{}
 
 var _ = Suite(&ShallowUpdateSuite{})
 
+func (s *ShallowUpdateSuite) TestDecodeWithLF(c *C) {
+	raw := "" +
+		"0035shallow aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n" +
+		"0035shallow bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n" +
+		"0000"
+
+	su := &ShallowUpdate{}
+	err := su.Decode(bytes.NewBufferString(raw))
+	c.Assert(err, IsNil)
+
+	plumbing.HashesSort(su.Shallows)
+
+	c.Assert(su.Unshallows, HasLen, 0)
+	c.Assert(su.Shallows, HasLen, 2)
+	c.Assert(su.Shallows, DeepEquals, []plumbing.Hash{
+		plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+		plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+	})
+}
+
 func (s *ShallowUpdateSuite) TestDecode(c *C) {
 	raw := "" +
 		"0034shallow aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" +
@@ -61,3 +81,70 @@ func (s *ShallowUpdateSuite) TestDecodeMalformed(c *C) {
 	err := su.Decode(bytes.NewBufferString(raw))
 	c.Assert(err, NotNil)
 }
+
+func (s *ShallowUpdateSuite) TestEncodeEmpty(c *C) {
+	su := &ShallowUpdate{}
+	buf := bytes.NewBuffer(nil)
+	c.Assert(su.Encode(buf), IsNil)
+	c.Assert(buf.String(), Equals, "0000")
+}
+
+func (s *ShallowUpdateSuite) TestEncode(c *C) {
+	su := &ShallowUpdate{
+		Shallows: []plumbing.Hash{
+			plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+			plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+		},
+		Unshallows: []plumbing.Hash{
+			plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+			plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+		},
+	}
+	buf := bytes.NewBuffer(nil)
+	c.Assert(su.Encode(buf), IsNil)
+
+	expected := "" +
+		"0035shallow aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n" +
+		"0035shallow bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n" +
+		"0037unshallow aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n" +
+		"0037unshallow bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n" +
+		"0000"
+
+	c.Assert(buf.String(), Equals, expected)
+}
+
+func (s *ShallowUpdateSuite) TestEncodeShallow(c *C) {
+	su := &ShallowUpdate{
+		Shallows: []plumbing.Hash{
+			plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+			plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+		},
+	}
+	buf := bytes.NewBuffer(nil)
+	c.Assert(su.Encode(buf), IsNil)
+
+	expected := "" +
+		"0035shallow aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n" +
+		"0035shallow bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n" +
+		"0000"
+
+	c.Assert(buf.String(), Equals, expected)
+}
+
+func (s *ShallowUpdateSuite) TestEncodeUnshallow(c *C) {
+	su := &ShallowUpdate{
+		Unshallows: []plumbing.Hash{
+			plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+			plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+		},
+	}
+	buf := bytes.NewBuffer(nil)
+	c.Assert(su.Encode(buf), IsNil)
+
+	expected := "" +
+		"0037unshallow aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n" +
+		"0037unshallow bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n" +
+		"0000"
+
+	c.Assert(buf.String(), Equals, expected)
+}
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())
+}
diff --git a/plumbing/protocol/packp/updreq_decode.go b/plumbing/protocol/packp/updreq_decode.go
index 51e8183..c15d49c 100644
--- a/plumbing/protocol/packp/updreq_decode.go
+++ b/plumbing/protocol/packp/updreq_decode.go
@@ -225,7 +225,7 @@ func parseCommand(b []byte) (*Command, error) {
 		return nil, errInvalidNewObjId(err)
 	}
 
-	return &Command{Old: oh, New: nh, Name: n}, nil
+	return &Command{Old: oh, New: nh, Name: plumbing.ReferenceName(n)}, nil
 }
 
 func parseHash(s string) (plumbing.Hash, error) {
diff --git a/plumbing/protocol/packp/uppackresp.go b/plumbing/protocol/packp/uppackresp.go
index a117956..ac456f3 100644
--- a/plumbing/protocol/packp/uppackresp.go
+++ b/plumbing/protocol/packp/uppackresp.go
@@ -5,6 +5,7 @@ import (
 	"io"
 
 	"gopkg.in/src-d/go-git.v4/plumbing/protocol/packp/capability"
+	"gopkg.in/src-d/go-git.v4/utils/ioutil"
 )
 
 // ErrUploadPackResponseNotDecoded is returned if Read is called without
@@ -17,8 +18,8 @@ var ErrUploadPackResponseNotDecoded = errors.New("upload-pack-response should be
 type UploadPackResponse struct {
 	ShallowUpdate
 	ServerResponse
-	r io.ReadCloser
 
+	r          io.ReadCloser
 	isShallow  bool
 	isMultiACK bool
 	isOk       bool
@@ -37,6 +38,16 @@ func NewUploadPackResponse(req *UploadPackRequest) *UploadPackResponse {
 	}
 }
 
+// NewUploadPackResponseWithPackfile creates a new UploadPackResponse instance,
+// and sets its packfile reader.
+func NewUploadPackResponseWithPackfile(req *UploadPackRequest,
+	pf io.ReadCloser) *UploadPackResponse {
+
+	r := NewUploadPackResponse(req)
+	r.r = pf
+	return r
+}
+
 // Decode decodes all the responses sent by upload-pack service into the struct
 // and prepares it to read the packfile using the Read method
 func (r *UploadPackResponse) Decode(reader io.ReadCloser) error {
@@ -56,6 +67,23 @@ func (r *UploadPackResponse) Decode(reader io.ReadCloser) error {
 	return nil
 }
 
+// Encode encodes an UploadPackResponse.
+func (r *UploadPackResponse) Encode(w io.Writer) (err error) {
+	if r.isShallow {
+		if err := r.ShallowUpdate.Encode(w); err != nil {
+			return err
+		}
+	}
+
+	if err := r.ServerResponse.Encode(w); err != nil {
+		return err
+	}
+
+	defer ioutil.CheckClose(r.r, &err)
+	_, err = io.Copy(w, r.r)
+	return err
+}
+
 // Read reads the packfile data, if the request was done with any Sideband
 // capability the content read should be demultiplexed. If the methods wasn't
 // called before the ErrUploadPackResponseNotDecoded will be return
diff --git a/plumbing/protocol/packp/uppackresp_test.go b/plumbing/protocol/packp/uppackresp_test.go
index c81bb76..c27fdda 100644
--- a/plumbing/protocol/packp/uppackresp_test.go
+++ b/plumbing/protocol/packp/uppackresp_test.go
@@ -7,6 +7,7 @@ import (
 	"gopkg.in/src-d/go-git.v4/plumbing/protocol/packp/capability"
 
 	. "gopkg.in/check.v1"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 type UploadPackResponseSuite struct{}
@@ -80,3 +81,46 @@ func (s *UploadPackResponseSuite) TestReadNoDecode(c *C) {
 	c.Assert(err, Equals, ErrUploadPackResponseNotDecoded)
 	c.Assert(n, Equals, 0)
 }
+
+func (s *UploadPackResponseSuite) TestEncodeNAK(c *C) {
+	pf := ioutil.NopCloser(bytes.NewBuffer([]byte("[PACK]")))
+	req := NewUploadPackRequest()
+	res := NewUploadPackResponseWithPackfile(req, pf)
+	defer func() { c.Assert(res.Close(), IsNil) }()
+
+	b := bytes.NewBuffer(nil)
+	c.Assert(res.Encode(b), IsNil)
+
+	expected := "0008NAK\n[PACK]"
+	c.Assert(string(b.Bytes()), Equals, expected)
+}
+
+func (s *UploadPackResponseSuite) TestEncodeDepth(c *C) {
+	pf := ioutil.NopCloser(bytes.NewBuffer([]byte("[PACK]")))
+	req := NewUploadPackRequest()
+	req.Depth = DepthCommits(1)
+
+	res := NewUploadPackResponseWithPackfile(req, pf)
+	defer func() { c.Assert(res.Close(), IsNil) }()
+
+	b := bytes.NewBuffer(nil)
+	c.Assert(res.Encode(b), IsNil)
+
+	expected := "00000008NAK\n[PACK]"
+	c.Assert(string(b.Bytes()), Equals, expected)
+}
+
+func (s *UploadPackResponseSuite) TestEncodeMultiACK(c *C) {
+	pf := ioutil.NopCloser(bytes.NewBuffer([]byte("[PACK]")))
+	req := NewUploadPackRequest()
+
+	res := NewUploadPackResponseWithPackfile(req, pf)
+	defer func() { c.Assert(res.Close(), IsNil) }()
+	res.ACKs = []plumbing.Hash{
+		plumbing.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f81"),
+		plumbing.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f82"),
+	}
+
+	b := bytes.NewBuffer(nil)
+	c.Assert(res.Encode(b), NotNil)
+}