transport: create Client interface (#132)

* plumbing: move plumbing/client package to plumbing/transport.

* transport: create Client interface.

* A Client can instantiate any client transport service.
* InstallProtocol installs a Client for a given protocol,
  instead of just a UploadPackService.
* A Client can open a session for fetch-pack or send-pack
  for a specific Endpoint.
* Adapt ssh and http clients to the new client interface.

* updated doc

1 files changed, 29 insertions, 0 deletions

diff --git a/plumbing/transport/http/send_pack.go b/plumbing/transport/http/send_pack.go
new file mode 100644
index 0000000..39be95c
--- /dev/null
+++ b/plumbing/transport/http/send_pack.go
@@ -0,0 +1,29 @@
+package http
+
+import (
+	"errors"
+	"io"
+	"net/http"
+
+	"gopkg.in/src-d/go-git.v4/plumbing/transport"
+)
+
+var errSendPackNotSupported = errors.New("send-pack not supported yet")
+
+type sendPackSession struct{
+	*session
+}
+
+func newSendPackSession(c *http.Client, ep transport.Endpoint) transport.SendPackSession {
+	return &sendPackSession{&session{}}
+}
+
+func (s *sendPackSession) AdvertisedReferences() (*transport.UploadPackInfo,
+	error) {
+
+	return nil, errSendPackNotSupported
+}
+
+func (s *sendPackSession) SendPack() (io.WriteCloser, error) {
+	return nil, errSendPackNotSupported
+}