[tor-commits] [snowflake/master] remove webRTCConn SendLoop and simplify Write without additional channel, as net.Conn is already safe

[serene at torproject.org]

commit d4efe774d109b094b81699a608cd1024e096bb64
Author: Serene Han <keroserene+git at gmail.com>
Date:   Tue Feb 23 17:34:51 2016 -0800

    remove webRTCConn SendLoop and simplify Write without additional channel, as net.Conn is already safe
---
 client/client_test.go | 14 ++++++--------
 client/snowflake.go   |  1 -
 client/webrtc.go      | 52 ++++++++++++++++++---------------------------------
 3 files changed, 24 insertions(+), 43 deletions(-)

diff --git a/client/client_test.go b/client/client_test.go
index cad40de..9acf6fc 100644
--- a/client/client_test.go
+++ b/client/client_test.go
@@ -33,19 +33,17 @@ func TestConnect(t *testing.T) {
 			}
 			So(c.buffer.Bytes(), ShouldEqual, nil)
 
-			Convey("sendData buffers when datachannel is nil", func() {
-				c.sendData([]byte("test"))
+			Convey("Write buffers when datachannel is nil", func() {
+				c.Write([]byte("test"))
 				c.snowflake = nil
 				So(c.buffer.Bytes(), ShouldResemble, []byte("test"))
 			})
 
-			Convey("sendData sends to datachannel when not nil", func() {
+			Convey("Write sends to datachannel when not nil", func() {
 				mock := new(MockDataChannel)
-				mock.done = make(chan bool)
-				go c.SendLoop()
-				c.writeChannel = make(chan []byte)
 				c.snowflake = mock
-				c.sendData([]byte("test"))
+				mock.done = make(chan bool, 1)
+				c.Write([]byte("test"))
 				<-mock.done
 				So(c.buffer.Bytes(), ShouldEqual, nil)
 				So(mock.destination.Bytes(), ShouldResemble, []byte("test"))
@@ -54,7 +52,7 @@ func TestConnect(t *testing.T) {
 			Convey("Receive answer sets remote description", func() {
 				c.answerChannel = make(chan *webrtc.SessionDescription)
 				c.config = webrtc.NewConfiguration()
-				c.PreparePeerConnection()
+				c.preparePeerConnection()
 				c.receiveAnswer()
 				sdp := webrtc.DeserializeSessionDescription("test")
 				c.answerChannel <- sdp
diff --git a/client/snowflake.go b/client/snowflake.go
index 29d263a..615038c 100644
--- a/client/snowflake.go
+++ b/client/snowflake.go
@@ -70,7 +70,6 @@ func dialWebRTC() (*webRTCConn, error) {
 
 	connection := NewWebRTCConnection(config, broker)
 	go connection.ConnectLoop()
-	go connection.SendLoop()
 
 	return connection, nil
 }
diff --git a/client/webrtc.go b/client/webrtc.go
index 89d1592..0c865fa 100644
--- a/client/webrtc.go
+++ b/client/webrtc.go
@@ -19,7 +19,6 @@ type webRTCConn struct {
 	offerChannel  chan *webrtc.SessionDescription
 	answerChannel chan *webrtc.SessionDescription
 	errorChannel  chan error
-	writeChannel  chan []byte
 	recvPipe      *io.PipeReader
 	writePipe     *io.PipeWriter
 	buffer        bytes.Buffer
@@ -33,8 +32,15 @@ func (c *webRTCConn) Read(b []byte) (int, error) {
 	return c.recvPipe.Read(b)
 }
 
+// Writes bytes out to the snowflake proxy.
 func (c *webRTCConn) Write(b []byte) (int, error) {
-	c.sendData(b)
+	c.BytesInfo.AddOutbound(len(b))
+	if nil == c.snowflake {
+		log.Printf("Buffered %d bytes --> WebRTC", len(b))
+		c.buffer.Write(b)
+	} else {
+		c.snowflake.Send(b)
+	}
 	return len(b), nil
 }
 
@@ -64,19 +70,18 @@ func (c *webRTCConn) SetWriteDeadline(t time.Time) error {
 }
 
 func NewWebRTCConnection(config *webrtc.Configuration,
-		broker *BrokerChannel) *webRTCConn {
+	broker *BrokerChannel) *webRTCConn {
 	connection := new(webRTCConn)
 	connection.config = config
 	connection.broker = broker
-	connection.offerChannel = make(chan *webrtc.SessionDescription)
-	connection.answerChannel = make(chan *webrtc.SessionDescription)
-	connection.writeChannel = make(chan []byte)
-	connection.errorChannel = make(chan error)
-	connection.reset = make(chan struct{})
+	connection.offerChannel = make(chan *webrtc.SessionDescription, 1)
+	connection.answerChannel = make(chan *webrtc.SessionDescription, 1)
+	connection.errorChannel = make(chan error, 1)
+	connection.reset = make(chan struct{}, 1)
 
 	// Log every few seconds.
 	connection.BytesInfo = &BytesInfo{
-		inboundChan: make(chan int), outboundChan: make(chan int),
+		inboundChan: make(chan int, 5), outboundChan: make(chan int, 5),
 		inbound: 0, outbound: 0, inEvents: 0, outEvents: 0,
 	}
 	go connection.BytesInfo.Log()
@@ -106,20 +111,6 @@ func (c *webRTCConn) ConnectLoop() {
 	}
 }
 
-// Expected in own goroutine.
-func (c *webRTCConn) SendLoop() {
-	log.Println("send loop")
-	for data := range c.writeChannel {
-		// Flush buffer if necessary.
-		for c.buffer.Len() > 0 {
-			c.snowflake.Send(c.buffer.Bytes())
-			log.Println("Flushed", c.buffer.Len(), "bytes")
-			c.buffer.Reset()
-		}
-		c.snowflake.Send(data)
-	}
-}
-
 func (c *webRTCConn) preparePeerConnection() {
 	if nil != c.pc {
 		c.pc.Close()
@@ -185,6 +176,7 @@ func (c *webRTCConn) establishDataChannel() error {
 		dc.Send(c.buffer.Bytes())
 		log.Println("Flushed", c.buffer.Len(), "bytes")
 		c.buffer.Reset()
+
 		c.snowflake = dc
 	}
 	dc.OnClose = func() {
@@ -198,6 +190,9 @@ func (c *webRTCConn) establishDataChannel() error {
 		}
 	}
 	dc.OnMessage = func(msg []byte) {
+		if len(msg) <= 0 {
+			log.Println("0 length---")
+		}
 		c.BytesInfo.AddInbound(len(msg))
 		n, err := c.writePipe.Write(msg)
 		if err != nil {
@@ -261,17 +256,6 @@ func (c *webRTCConn) receiveAnswer() {
 	}()
 }
 
-func (c *webRTCConn) sendData(data []byte) {
-	c.BytesInfo.AddOutbound(len(data))
-	// Buffer the data in case datachannel isn't available yet.
-	if nil == c.snowflake {
-		log.Printf("Buffered %d bytes --> WebRTC", len(data))
-		c.buffer.Write(data)
-		return
-	}
-	c.writeChannel <- data
-}
-
 func (c *webRTCConn) Reset() {
 	go func() {
 		c.reset <- struct{}{} // Attempt to negotiate a new datachannel..