Use single encoder/decoder and buffered io

Update Send and Receive objects to lock access and save their encoder/decoder.  Additionally use a buffered writer on encode.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

spdy/session.go

@@ -1,7 +1,7 @@
 package spdy
 
 import (
-	"bytes"
+	"bufio"
 	"errors"
 	"io"
 	"net"
@@ -48,6 +48,11 @@ type channel struct {
 	stream      *spdystream.Stream
 	session     *Transport
 	direction   direction
+	encodeLock  sync.Mutex
+	encoder     *msgpack.Encoder
+	decodeLock  sync.Mutex
+	decoder     *msgpack.Decoder
+	buffer      *bufio.Writer
 }
 
 // NewClientTransport creates a new stream transport from the
@@ -126,6 +131,7 @@ func (s *Transport) newStreamHandler(stream *spdystream.Stream) {
 					stream:      stream,
 					session:     s,
 				}
+
 				s.channelC.L.Lock()
 				s.channels[referenceID] = c
 				s.channelC.Broadcast()
@@ -306,21 +312,19 @@ func (c *channel) Send(message interface{}) error {
 		return ErrWrongDirection
 	}
 
-	buf := bytes.NewBuffer(nil)
-	encoder := msgpack.NewEncoder(buf)
-	encoder.AddExtensions(c.initializeExtensions())
-	encodeErr := encoder.Encode(message)
-	if encodeErr != nil {
-		return encodeErr
+	c.encodeLock.Lock()
+	defer c.encodeLock.Unlock()
+	if c.encoder == nil {
+		c.buffer = bufio.NewWriter(c.stream)
+		c.encoder = msgpack.NewEncoder(c.buffer)
+		c.encoder.AddExtensions(c.initializeExtensions())
 	}
 
-	// TODO check length of buf
-	_, writeErr := c.stream.Write(buf.Bytes())
-	if writeErr != nil {
-		return writeErr
+	if err := c.encoder.Encode(message); err != nil {
+		return err
 	}
 
-	return nil
+	return c.buffer.Flush()
 }
 
 // Receive receives a message sent across the channel from
@@ -329,21 +333,20 @@ func (c *channel) Receive(message interface{}) error {
 	if c.direction == outbound {
 		return ErrWrongDirection
 	}
-	buf, readErr := c.stream.ReadData()
-	if readErr != nil {
-		if readErr == io.EOF {
-			c.stream.Close()
-		}
-		return readErr
+
+	c.decodeLock.Lock()
+	defer c.decodeLock.Unlock()
+	if c.decoder == nil {
+		c.decoder = msgpack.NewDecoder(c.stream)
+		c.decoder.AddExtensions(c.initializeExtensions())
 	}
 
-	decoder := msgpack.NewDecoder(bytes.NewReader(buf))
-	decoder.AddExtensions(c.initializeExtensions())
-	decodeErr := decoder.Decode(message)
-	if decodeErr != nil {
-		return decodeErr
+	decodeErr := c.decoder.Decode(message)
+	if decodeErr == io.EOF {
+		c.stream.Close()
+		c.decoder = nil
 	}
-	return nil
+	return decodeErr
 }
 
 func (c *channel) SendTo(dst libchan.Sender) (int, error) {