transport: add local transport (#145)

* transport: move common packp protocol out of ssh transport.
* fixtures: add fixture for empty repository.
* transport: add file:// transport

4 files changed, 48 insertions, 330 deletions

diff --git a/plumbing/transport/ssh/common.go b/plumbing/transport/ssh/common.go
index c327c41..a88a328 100644
--- a/plumbing/transport/ssh/common.go
+++ b/plumbing/transport/ssh/common.go
@@ -3,10 +3,10 @@ package ssh
 import (
 	"errors"
 	"fmt"
-	"io"
 	"strings"
 
 	"gopkg.in/src-d/go-git.v4/plumbing/transport"
+	"gopkg.in/src-d/go-git.v4/plumbing/transport/internal/common"
 
 	"golang.org/x/crypto/ssh"
 )
@@ -15,155 +15,110 @@ var (
 	errAlreadyConnected = errors.New("ssh session already created")
 )
 
-type client struct{}
-
 // DefaultClient is the default SSH client.
-var DefaultClient = &client{}
-
-func (c *client) NewFetchPackSession(ep transport.Endpoint) (
-	transport.FetchPackSession, error) {
+var DefaultClient = common.NewClient(&runner{})
 
-	return newFetchPackSession(ep)
-}
+type runner struct{}
 
-func (c *client) NewSendPackSession(ep transport.Endpoint) (
-	transport.SendPackSession, error) {
+func (r *runner) Command(cmd string, ep transport.Endpoint) (common.Command, error) {
+	c := &command{command: cmd, endpoint: ep}
+	if err := c.connect(); err != nil {
+		return nil, err
+	}
 
-	return newSendPackSession(ep)
+	return c, nil
 }
 
-type session struct {
-	connected   bool
-	endpoint    transport.Endpoint
-	client      *ssh.Client
-	session     *ssh.Session
-	stdin       io.WriteCloser
-	stdout      io.Reader
-	stderr      io.Reader
-	sessionDone chan error
-	auth        AuthMethod
+type command struct {
+	*ssh.Session
+	connected bool
+	command   string
+	endpoint  transport.Endpoint
+	client    *ssh.Client
+	auth      AuthMethod
 }
 
-func (s *session) SetAuth(auth transport.AuthMethod) error {
+func (c *command) SetAuth(auth transport.AuthMethod) error {
 	a, ok := auth.(AuthMethod)
 	if !ok {
 		return transport.ErrInvalidAuthMethod
 	}
 
-	s.auth = a
+	c.auth = a
 	return nil
 }
 
-// Close closes the SSH session.
-func (s *session) Close() error {
-	if !s.connected {
+func (c *command) Start() error {
+	return c.Session.Start(endpointToCommand(c.command, c.endpoint))
+}
+
+// Close closes the SSH session and connection.
+func (c *command) Close() error {
+	if !c.connected {
 		return nil
 	}
 
-	s.connected = false
+	c.connected = false
 
 	//XXX: If did read the full packfile, then the session might be already
 	//     closed.
-	_ = s.session.Close()
+	_ = c.Session.Close()
 
-	return s.client.Close()
+	return c.client.Close()
 }
 
-// ensureConnected connects to the SSH server, unless a AuthMethod was set with
+// connect connects to the SSH server, unless a AuthMethod was set with
 // SetAuth method, by default uses an auth method based on PublicKeysCallback,
 // it connects to a SSH agent, using the address stored in the SSH_AUTH_SOCK
 // environment var.
-func (s *session) connect() error {
-	if s.connected {
+func (c *command) connect() error {
+	if c.connected {
 		return errAlreadyConnected
 	}
 
-	if err := s.setAuthFromEndpoint(); err != nil {
+	if err := c.setAuthFromEndpoint(); err != nil {
 		return err
 	}
 
 	var err error
-	s.client, err = ssh.Dial("tcp", s.getHostWithPort(), s.auth.clientConfig())
+	c.client, err = ssh.Dial("tcp", c.getHostWithPort(), c.auth.clientConfig())
 	if err != nil {
 		return err
 	}
 
-	if err := s.openSSHSession(); err != nil {
-		_ = s.client.Close()
+	c.Session, err = c.client.NewSession()
+	if err != nil {
+		_ = c.client.Close()
 		return err
 	}
 
-	s.connected = true
+	c.connected = true
 	return nil
 }
 
-func (s *session) getHostWithPort() string {
-	host := s.endpoint.Host
-	if strings.Index(s.endpoint.Host, ":") == -1 {
+func (c *command) getHostWithPort() string {
+	host := c.endpoint.Host
+	if strings.Index(c.endpoint.Host, ":") == -1 {
 		host += ":22"
 	}
 
 	return host
 }
 
-func (s *session) setAuthFromEndpoint() error {
+func (c *command) setAuthFromEndpoint() error {
 	var u string
-	if info := s.endpoint.User; info != nil {
+	if info := c.endpoint.User; info != nil {
 		u = info.Username()
 	}
 
 	var err error
-	s.auth, err = NewSSHAgentAuth(u)
+	c.auth, err = NewSSHAgentAuth(u)
 	return err
 }
 
-func (s *session) openSSHSession() error {
-	var err error
-	s.session, err = s.client.NewSession()
-	if err != nil {
-		return fmt.Errorf("cannot open SSH session: %s", err)
-	}
-
-	s.stdin, err = s.session.StdinPipe()
-	if err != nil {
-		return fmt.Errorf("cannot pipe remote stdin: %s", err)
-	}
-
-	s.stdout, err = s.session.StdoutPipe()
-	if err != nil {
-		return fmt.Errorf("cannot pipe remote stdout: %s", err)
-	}
-
-	s.stderr, err = s.session.StderrPipe()
-	if err != nil {
-		return fmt.Errorf("cannot pipe remote stderr: %s", err)
-	}
-
-	return nil
-}
-
-func (s *session) runCommand(cmd string) chan error {
-	done := make(chan error)
-	go func() {
-		done <- s.session.Run(cmd)
-	}()
-
-	return done
-}
-
-const (
-	githubRepoNotFoundErr    = "ERROR: Repository not found."
-	bitbucketRepoNotFoundErr = "conq: repository does not exist."
-)
-
-func isRepoNotFoundError(s string) bool {
-	if strings.HasPrefix(s, githubRepoNotFoundErr) {
-		return true
-	}
-
-	if strings.HasPrefix(s, bitbucketRepoNotFoundErr) {
-		return true
-	}
+func endpointToCommand(cmd string, ep transport.Endpoint) string {
+	directory := ep.Path
+	directory = directory[1:]
 
-	return false
+	return fmt.Sprintf("%s '%s'", cmd, directory)
 }
diff --git a/plumbing/transport/ssh/fetch_pack.go b/plumbing/transport/ssh/fetch_pack.go
deleted file mode 100644
index a0f52f1..0000000
--- a/plumbing/transport/ssh/fetch_pack.go
+++ /dev/null
@@ -1,208 +0,0 @@
-// Package ssh implements a ssh client for go-git.
-package ssh
-
-import (
-	"bufio"
-	"bytes"
-	"fmt"
-	"io"
-
-	"gopkg.in/src-d/go-git.v4/plumbing/format/pktline"
-	"gopkg.in/src-d/go-git.v4/plumbing/protocol/packp"
-	"gopkg.in/src-d/go-git.v4/plumbing/transport"
-	"gopkg.in/src-d/go-git.v4/utils/ioutil"
-
-	"golang.org/x/crypto/ssh"
-)
-
-type fetchPackSession struct {
-	*session
-	cmdRun     bool
-	advRefsRun bool
-	done       chan error
-}
-
-func newFetchPackSession(ep transport.Endpoint) (*fetchPackSession, error) {
-	s := &fetchPackSession{
-		session: &session{
-			endpoint: ep,
-		},
-	}
-	if err := s.connect(); err != nil {
-		return nil, err
-	}
-
-	return s, nil
-}
-
-func (s *fetchPackSession) AdvertisedReferences() (*packp.AdvRefs, error) {
-	if s.advRefsRun {
-		return nil, transport.ErrAdvertistedReferencesAlreadyCalled
-	}
-
-	defer func() { s.advRefsRun = true }()
-
-	if err := s.ensureRunCommand(); err != nil {
-		return nil, err
-	}
-
-	ar := packp.NewAdvRefs()
-	if err := ar.Decode(s.stdout); err != nil {
-		if err != packp.ErrEmptyAdvRefs {
-			return nil, err
-		}
-
-		_ = s.stdin.Close()
-		scan := bufio.NewScanner(s.stderr)
-		if !scan.Scan() {
-			return nil, transport.ErrEmptyRemoteRepository
-		}
-
-		if isRepoNotFoundError(string(scan.Bytes())) {
-			return nil, transport.ErrRepositoryNotFound
-		}
-
-		return nil, err
-	}
-
-	return ar, nil
-}
-
-// FetchPack returns a packfile for a given upload request.
-// Closing the returned reader will close the SSH session.
-func (s *fetchPackSession) FetchPack(req *packp.UploadPackRequest) (
-	io.ReadCloser, error) {
-
-	if req.IsEmpty() {
-		return nil, transport.ErrEmptyUploadPackRequest
-	}
-
-	if !s.advRefsRun {
-		if _, err := s.AdvertisedReferences(); err != nil {
-			return nil, err
-		}
-	}
-
-	if err := fetchPack(s.stdin, s.stdout, req); err != nil {
-		return nil, err
-	}
-
-	fs := &fetchSession{
-		Reader:  s.stdout,
-		session: s.session.session,
-		done:    s.done,
-	}
-
-	r, err := ioutil.NonEmptyReader(fs)
-	if err == ioutil.ErrEmptyReader {
-		_ = fs.Close()
-		return nil, transport.ErrEmptyUploadPackRequest
-	}
-
-	return ioutil.NewReadCloser(r, fs), nil
-}
-
-func (s *fetchPackSession) ensureRunCommand() error {
-	if s.cmdRun {
-		return nil
-	}
-
-	s.cmdRun = true
-	s.done = s.runCommand(s.getCommand())
-	return nil
-}
-
-type fetchSession struct {
-	io.Reader
-	session *ssh.Session
-	done    <-chan error
-}
-
-// Close closes the session and collects the output state of the remote
-// SSH command.
-//
-// If both the remote command and the closing of the session completes
-// susccessfully it returns nil.
-//
-// If the remote command completes unsuccessfully or is interrupted by a
-// signal, it returns the corresponding *ExitError.
-//
-// Otherwise, if clossing the SSH session fails it returns the close
-// error.  Closing the session when the other has already close it is
-// not cosidered an error.
-func (f *fetchSession) Close() (err error) {
-	if err := <-f.done; err != nil {
-		return err
-	}
-
-	if err := f.session.Close(); err != nil && err != io.EOF {
-		return err
-	}
-
-	return nil
-}
-
-func (s *fetchPackSession) getCommand() string {
-	directory := s.endpoint.Path
-	directory = directory[1:]
-
-	return fmt.Sprintf("git-upload-pack '%s'", directory)
-}
-
-var (
-	nak = []byte("NAK")
-	eol = []byte("\n")
-)
-
-// FetchPack implements the git-fetch-pack protocol.
-//
-// TODO support multi_ack mode
-// TODO support multi_ack_detailed mode
-// TODO support acks for common objects
-// TODO build a proper state machine for all these processing options
-func fetchPack(w io.WriteCloser, r io.Reader,
-	req *packp.UploadPackRequest) error {
-
-	if err := req.UploadRequest.Encode(w); err != nil {
-		return fmt.Errorf("sending upload-req message: %s", err)
-	}
-
-	if err := req.UploadHaves.Encode(w); err != nil {
-		return fmt.Errorf("sending haves message: %s", err)
-	}
-
-	if err := sendDone(w); err != nil {
-		return fmt.Errorf("sending done message: %s", err)
-	}
-
-	if err := w.Close(); err != nil {
-		return fmt.Errorf("closing input: %s", err)
-	}
-
-	if err := readNAK(r); err != nil {
-		return fmt.Errorf("reading NAK: %s", err)
-	}
-
-	return nil
-}
-
-func sendDone(w io.Writer) error {
-	e := pktline.NewEncoder(w)
-
-	return e.Encodef("done\n")
-}
-
-func readNAK(r io.Reader) error {
-	s := pktline.NewScanner(r)
-	if !s.Scan() {
-		return s.Err()
-	}
-
-	b := s.Bytes()
-	b = bytes.TrimSuffix(b, eol)
-	if !bytes.Equal(b, nak) {
-		return fmt.Errorf("expecting NAK, found %q instead", string(b))
-	}
-
-	return nil
-}
diff --git a/plumbing/transport/ssh/fetch_pack_test.go b/plumbing/transport/ssh/fetch_pack_test.go
index a0321b3..927e9a8 100644
--- a/plumbing/transport/ssh/fetch_pack_test.go
+++ b/plumbing/transport/ssh/fetch_pack_test.go
@@ -33,4 +33,5 @@ func (s *FetchPackSuite) SetUpSuite(c *C) {
 	ep, err = transport.NewEndpoint("git@github.com:git-fixtures/non-existent.git")
 	c.Assert(err, IsNil)
 	s.FetchPackSuite.NonExistentEndpoint = ep
+
 }
diff --git a/plumbing/transport/ssh/send_pack.go b/plumbing/transport/ssh/send_pack.go
deleted file mode 100644
index adf67bb..0000000
--- a/plumbing/transport/ssh/send_pack.go
+++ /dev/null
@@ -1,30 +0,0 @@
-package ssh
-
-import (
-	"errors"
-	"io"
-
-	"gopkg.in/src-d/go-git.v4/plumbing/protocol/packp"
-	"gopkg.in/src-d/go-git.v4/plumbing/transport"
-)
-
-var errSendPackNotSupported = errors.New("send-pack not supported yet")
-
-type sendPackSession struct {
-	*session
-}
-
-func newSendPackSession(ep transport.Endpoint) (transport.SendPackSession,
-	error) {
-
-	return &sendPackSession{&session{}}, nil
-}
-
-func (s *sendPackSession) AdvertisedReferences() (*packp.AdvRefs, error) {
-
-	return nil, errSendPackNotSupported
-}
-
-func (s *sendPackSession) SendPack() (io.WriteCloser, error) {
-	return nil, errSendPackNotSupported
-}