sftp: add required packages to vendor

vendor/github.com/pkg/sftp/conn.go

@@ -0,0 +1,126 @@
+package sftp
+
+import (
+	"encoding"
+	"io"
+	"sync"
+
+	"github.com/pkg/errors"
+)
+
+// conn implements a bidirectional channel on which client and server
+// connections are multiplexed.
+type conn struct {
+	io.Reader
+	io.WriteCloser
+	sync.Mutex // used to serialise writes to sendPacket
+}
+
+func (c *conn) recvPacket() (uint8, []byte, error) {
+	return recvPacket(c)
+}
+
+func (c *conn) sendPacket(m encoding.BinaryMarshaler) error {
+	c.Lock()
+	defer c.Unlock()
+	return sendPacket(c, m)
+}
+
+type clientConn struct {
+	conn
+	wg         sync.WaitGroup
+	sync.Mutex                          // protects inflight
+	inflight   map[uint32]chan<- result // outstanding requests
+}
+
+// Close closes the SFTP session.
+func (c *clientConn) Close() error {
+	defer c.wg.Wait()
+	return c.conn.Close()
+}
+
+func (c *clientConn) loop() {
+	defer c.wg.Done()
+	err := c.recv()
+	if err != nil {
+		c.broadcastErr(err)
+	}
+}
+
+// recv continuously reads from the server and forwards responses to the
+// appropriate channel.
+func (c *clientConn) recv() error {
+	defer func() {
+		c.Lock()
+		c.conn.Close()
+		c.Unlock()
+	}()
+	for {
+		typ, data, err := c.recvPacket()
+		if err != nil {
+			return err
+		}
+		sid, _ := unmarshalUint32(data)
+		c.Lock()
+		ch, ok := c.inflight[sid]
+		delete(c.inflight, sid)
+		c.Unlock()
+		if !ok {
+			// This is an unexpected occurrence. Send the error
+			// back to all listeners so that they terminate
+			// gracefully.
+			return errors.Errorf("sid: %v not fond", sid)
+		}
+		ch <- result{typ: typ, data: data}
+	}
+}
+
+// result captures the result of receiving the a packet from the server
+type result struct {
+	typ  byte
+	data []byte
+	err  error
+}
+
+type idmarshaler interface {
+	id() uint32
+	encoding.BinaryMarshaler
+}
+
+func (c *clientConn) sendPacket(p idmarshaler) (byte, []byte, error) {
+	ch := make(chan result, 1)
+	c.dispatchRequest(ch, p)
+	s := <-ch
+	return s.typ, s.data, s.err
+}
+
+func (c *clientConn) dispatchRequest(ch chan<- result, p idmarshaler) {
+	c.Lock()
+	c.inflight[p.id()] = ch
+	if err := c.conn.sendPacket(p); err != nil {
+		delete(c.inflight, p.id())
+		ch <- result{err: err}
+	}
+	c.Unlock()
+}
+
+// broadcastErr sends an error to all goroutines waiting for a response.
+func (c *clientConn) broadcastErr(err error) {
+	c.Lock()
+	listeners := make([]chan<- result, 0, len(c.inflight))
+	for _, ch := range c.inflight {
+		listeners = append(listeners, ch)
+	}
+	c.Unlock()
+	for _, ch := range listeners {
+		ch <- result{err: err}
+	}
+}
+
+type serverConn struct {
+	conn
+}
+
+func (s *serverConn) sendError(p id, err error) error {
+	return s.sendPacket(statusFromError(p, err))
+}