Buffer local and remote messages

kylecarbs · kylecarbs · commit e87d2cb775df · 2022-01-31T00:23:37.000Z
diff --git a/peer/conn.go b/peer/conn.go
@@ -74,9 +74,10 @@ func newWithClientOrServer(servers []webrtc.ICEServer, client bool, opts *ConnOp
 		dcOpenChannel:                   make(chan *webrtc.DataChannel),
 		dcDisconnectChannel:             make(chan struct{}),
 		dcFailedChannel:                 make(chan struct{}),
+		iceStableChannel:                make(chan struct{}),
 		localCandidateChannel:           make(chan webrtc.ICECandidateInit),
-		localSessionDescriptionChannel:  make(chan webrtc.SessionDescription),
-		remoteSessionDescriptionChannel: make(chan webrtc.SessionDescription),
+		localSessionDescriptionChannel:  make(chan webrtc.SessionDescription, 1),
+		remoteSessionDescriptionChannel: make(chan webrtc.SessionDescription, 1),
 	}
 	if client {
 		// If we're the client, we want to flip the echo and
@@ -122,6 +123,7 @@ type Conn struct {
 	dcFailedListeners     atomic.Uint32
 	dcClosedWaitGroup     sync.WaitGroup
 
+	iceStableChannel                chan struct{}
 	localCandidateChannel           chan webrtc.ICECandidateInit
 	localSessionDescriptionChannel  chan webrtc.SessionDescription
 	remoteSessionDescriptionChannel chan webrtc.SessionDescription
@@ -219,6 +221,13 @@ func (c *Conn) init() error {
 	c.rtc.OnSignalingStateChange(func(signalState webrtc.SignalingState) {
 		c.opts.Logger.Debug(context.Background(), "signaling state updated",
 			slog.F("state", signalState))
+
+		if signalState == webrtc.SignalingStateStable {
+			select {
+			case c.iceStableChannel <- struct{}{}:
+			default:
+			}
+		}
 	})
 	c.rtc.OnICECandidate(func(iceCandidate *webrtc.ICECandidate) {
 		if iceCandidate == nil {
@@ -329,6 +338,15 @@ func (c *Conn) negotiate() {
 		}
 		c.opts.Logger.Debug(context.Background(), "sent answer")
 	}
+
+	if c.rtc.SignalingState() != webrtc.SignalingStateStable {
+		c.opts.Logger.Debug(context.Background(), "waiting for stable signaling state...")
+		select {
+		case <-c.closed:
+			return
+		case <-c.iceStableChannel:
+		}
+	}
 }
 
 // AddRemoteCandidate adds a remote candidate to the RTC connection.
