commit 81d14ad33a21ac487cefb2912a32a72a7cc8ee39 Author: David Fifield <david@bamsoftware.com> Date: Thu Apr 23 20:13:16 2020 -0600 Make WebRTCPeer.preparePeerConnection block. Formerly, preparePeerConnection set up a callback that sent into a channel, and exchangeSDP waited until it could receive from the channel. We can move the channel entirely into preparePeerConnection (having it not return until the callback has been called) and that way remove some shared state. --- client/lib/webrtc.go | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/client/lib/webrtc.go b/client/lib/webrtc.go index e4ac8e0..d489096 100644 --- a/client/lib/webrtc.go +++ b/client/lib/webrtc.go @@ -24,11 +24,10 @@ type WebRTCPeer struct { transport *webrtc.DataChannel broker *BrokerChannel - offerChannel chan *webrtc.SessionDescription - recvPipe *io.PipeReader - writePipe *io.PipeWriter - lastReceive time.Time - buffer bytes.Buffer + recvPipe *io.PipeReader + writePipe *io.PipeWriter + lastReceive time.Time + buffer bytes.Buffer closed bool @@ -51,7 +50,6 @@ func NewWebRTCPeer(config *webrtc.Configuration, } connection.config = config connection.broker = broker - connection.offerChannel = make(chan *webrtc.SessionDescription, 1) // Override with something that's not NullLogger to have real logging. connection.BytesLogger = &BytesNullLogger{} @@ -153,11 +151,12 @@ func (c *WebRTCPeer) preparePeerConnection() error { return err } // Prepare PeerConnection callbacks. + offerChannel := make(chan struct{}) // Allow candidates to accumulate until ICEGatheringStateComplete. pc.OnICECandidate(func(candidate *webrtc.ICECandidate) { if candidate == nil { log.Printf("WebRTC: Done gathering candidates") - c.offerChannel <- pc.LocalDescription() + close(offerChannel) } else { log.Printf("WebRTC: Got ICE candidate: %s", candidate.String()) } @@ -180,6 +179,7 @@ func (c *WebRTCPeer) preparePeerConnection() error { } log.Println("WebRTC: Set local description") + <-offerChannel // Wait for ICE candidate gathering to complete. log.Println("WebRTC: PeerConnection created.") return nil } @@ -254,10 +254,9 @@ func (c *WebRTCPeer) establishDataChannel() error { return nil } -// exchangeSDP blocks until an SDP offer is available, sends it to the Broker, -// then awaits the SDP answer. +// exchangeSDP sends the local SDP offer to the Broker and awaits the SDP +// answer. func (c *WebRTCPeer) exchangeSDP() error { - <-c.offerChannel // Keep trying the same offer until a valid answer arrives. var answer *webrtc.SessionDescription for { @@ -282,9 +281,6 @@ func (c *WebRTCPeer) exchangeSDP() error { // Close all channels and transports func (c *WebRTCPeer) cleanup() { - if nil != c.offerChannel { - close(c.offerChannel) - } // Close this side of the SOCKS pipe. if nil != c.writePipe { c.writePipe.Close()