Use Notification Queue from 67cc918 more

Deliver Candidates and Selected CandidatePairs using the same queue.
This means that things are delivered in order and we don't have to worry
about blocking

agent.go

@@ -128,9 +128,9 @@ type Agent struct {
 	gatherCandidateCancel func()
 	gatherCandidateDone   chan struct{}
 
-	chanCandidate     chan Candidate
-	chanCandidatePair chan *CandidatePair
-	stateNotifier     *connectionStateNotifier
+	connectionStateNotifier       *handlerNotifier
+	candidateNotifier             *handlerNotifier
+	selectedCandidatePairNotifier *handlerNotifier
 
 	loggerFactory logging.LoggerFactory
 	log           logging.LeveledLogger
@@ -227,8 +227,6 @@ func (a *Agent) taskLoop() {
 
 		after()
 
-		close(a.chanCandidate)
-		close(a.chanCandidatePair)
 		close(a.taskLoopDone)
 	}()
 
@@ -276,32 +274,30 @@ func NewAgent(config *AgentConfig) (*Agent, error) { //nolint:gocognit
 	startedCtx, startedFn := context.WithCancel(context.Background())
 
 	a := &Agent{
-		chanTask:          make(chan task),
-		chanCandidate:     make(chan Candidate),
-		chanCandidatePair: make(chan *CandidatePair),
-		tieBreaker:        globalMathRandomGenerator.Uint64(),
-		lite:              config.Lite,
-		gatheringState:    GatheringStateNew,
-		connectionState:   ConnectionStateNew,
-		localCandidates:   make(map[NetworkType][]Candidate),
-		remoteCandidates:  make(map[NetworkType][]Candidate),
-		urls:              config.Urls,
-		networkTypes:      config.NetworkTypes,
-		onConnected:       make(chan struct{}),
-		buf:               packetio.NewBuffer(),
-		done:              make(chan struct{}),
-		taskLoopDone:      make(chan struct{}),
-		startedCh:         startedCtx.Done(),
-		startedFn:         startedFn,
-		portMin:           config.PortMin,
-		portMax:           config.PortMax,
-		loggerFactory:     loggerFactory,
-		log:               log,
-		net:               config.Net,
-		proxyDialer:       config.ProxyDialer,
-		tcpMux:            config.TCPMux,
-		udpMux:            config.UDPMux,
-		udpMuxSrflx:       config.UDPMuxSrflx,
+		chanTask:         make(chan task),
+		tieBreaker:       globalMathRandomGenerator.Uint64(),
+		lite:             config.Lite,
+		gatheringState:   GatheringStateNew,
+		connectionState:  ConnectionStateNew,
+		localCandidates:  make(map[NetworkType][]Candidate),
+		remoteCandidates: make(map[NetworkType][]Candidate),
+		urls:             config.Urls,
+		networkTypes:     config.NetworkTypes,
+		onConnected:      make(chan struct{}),
+		buf:              packetio.NewBuffer(),
+		done:             make(chan struct{}),
+		taskLoopDone:     make(chan struct{}),
+		startedCh:        startedCtx.Done(),
+		startedFn:        startedFn,
+		portMin:          config.PortMin,
+		portMax:          config.PortMax,
+		loggerFactory:    loggerFactory,
+		log:              log,
+		net:              config.Net,
+		proxyDialer:      config.ProxyDialer,
+		tcpMux:           config.TCPMux,
+		udpMux:           config.UDPMux,
+		udpMuxSrflx:      config.UDPMuxSrflx,
 
 		mDNSMode: mDNSMode,
 		mDNSName: mDNSName,
@@ -320,7 +316,9 @@ func NewAgent(config *AgentConfig) (*Agent, error) { //nolint:gocognit
 
 		disableActiveTCP: config.DisableActiveTCP,
 	}
-	a.stateNotifier = &connectionStateNotifier{NotificationFunc: a.onConnectionStateChange}
+	a.connectionStateNotifier = &handlerNotifier{connectionStateFunc: a.onConnectionStateChange}
+	a.candidateNotifier = &handlerNotifier{candidateFunc: a.onCandidate}
+	a.selectedCandidatePairNotifier = &handlerNotifier{candidatePairFunc: a.onSelectedCandidatePairChange}
 
 	if a.net == nil {
 		a.net, err = stdnet.NewNet()
@@ -364,12 +362,6 @@ func NewAgent(config *AgentConfig) (*Agent, error) { //nolint:gocognit
 
 	go a.taskLoop()
 
-	// CandidatePair and ConnectionState are usually changed at once.
-	// Blocking one by the other one causes deadlock.
-	// Hence, we call handlers from independent Goroutines.
-	go a.candidatePairRoutine()
-	go a.candidateRoutine()
-
 	// Restart is also used to initialize the agent for the first time
 	if err := a.Restart(config.LocalUfrag, config.LocalPwd); err != nil {
 		a.closeMulticastConn()
@@ -501,7 +493,7 @@ func (a *Agent) updateConnectionState(newState ConnectionState) {
 
 		a.log.Infof("Setting new connection state: %s", newState)
 		a.connectionState = newState
-		a.stateNotifier.Enqueue(newState)
+		a.connectionStateNotifier.EnqueueConnectionState(newState)
 	}
 }
 
@@ -520,12 +512,7 @@ func (a *Agent) setSelectedPair(p *CandidatePair) {
 	a.updateConnectionState(ConnectionStateConnected)
 
 	// Notify when the selected pair changes
-	a.afterRun(func(ctx context.Context) {
-		select {
-		case a.chanCandidatePair <- p:
-		case <-ctx.Done():
-		}
-	})
+	a.selectedCandidatePairNotifier.EnqueueSelectedCandidatePair(p)
 
 	// Signal connected
 	a.onConnectedOnce.Do(func() { close(a.onConnected) })
@@ -761,7 +748,7 @@ func (a *Agent) addRemotePassiveTCPCandidate(remoteCandidate Candidate) {
 
 		localCandidate.start(a, conn, a.startedCh)
 		a.localCandidates[localCandidate.NetworkType()] = append(a.localCandidates[localCandidate.NetworkType()], localCandidate)
-		a.chanCandidate <- localCandidate
+		a.candidateNotifier.EnqueueCandidate(localCandidate)
 
 		a.addPair(localCandidate, remoteCandidate)
 	}
@@ -831,7 +818,7 @@ func (a *Agent) addCandidate(ctx context.Context, c Candidate, candidateConn net
 
 		a.requestConnectivityCheck()
 
-		a.chanCandidate <- c
+		a.candidateNotifier.EnqueueCandidate(c)
 	})
 }
 
@@ -1267,7 +1254,7 @@ func (a *Agent) setGatheringState(newState GatheringState) error {
 	done := make(chan struct{})
 	if err := a.run(a.context(), func(context.Context, *Agent) {
 		if a.gatheringState != newState && newState == GatheringStateComplete {
-			a.chanCandidate <- nil
+			a.candidateNotifier.EnqueueCandidate(nil)
 		}
 
 		a.gatheringState = newState

agent_handlers.go

@@ -43,46 +43,94 @@ func (a *Agent) onConnectionStateChange(s ConnectionState) {
 	}
 }
 
-func (a *Agent) candidatePairRoutine() {
-	for p := range a.chanCandidatePair {
-		a.onSelectedCandidatePairChange(p)
-	}
-}
-
-type connectionStateNotifier struct {
+type handlerNotifier struct {
 	sync.Mutex
-	states           []ConnectionState
-	running          bool
-	NotificationFunc func(ConnectionState)
+	running bool
+
+	connectionStates    []ConnectionState
+	connectionStateFunc func(ConnectionState)
+
+	candidates    []Candidate
+	candidateFunc func(Candidate)
+
+	selectedCandidatePairs []*CandidatePair
+	candidatePairFunc      func(*CandidatePair)
 }
 
-func (c *connectionStateNotifier) Enqueue(s ConnectionState) {
-	c.Lock()
-	defer c.Unlock()
-	c.states = append(c.states, s)
-	if !c.running {
-		c.running = true
-		go c.notify()
+func (h *handlerNotifier) EnqueueConnectionState(s ConnectionState) {
+	h.Lock()
+	defer h.Unlock()
+
+	notify := func() {
+		for {
+			h.Lock()
+			if len(h.connectionStates) == 0 {
+				h.running = false
+				h.Unlock()
+				return
+			}
+			notification := h.connectionStates[0]
+			h.connectionStates = h.connectionStates[1:]
+			h.Unlock()
+			h.connectionStateFunc(notification)
+		}
+	}
+
+	h.connectionStates = append(h.connectionStates, s)
+	if !h.running {
+		h.running = true
+		go notify()
 	}
 }
 
-func (c *connectionStateNotifier) notify() {
-	for {
-		c.Lock()
-		if len(c.states) == 0 {
-			c.running = false
-			c.Unlock()
-			return
+func (h *handlerNotifier) EnqueueCandidate(c Candidate) {
+	h.Lock()
+	defer h.Unlock()
+
+	notify := func() {
+		for {
+			h.Lock()
+			if len(h.candidates) == 0 {
+				h.running = false
+				h.Unlock()
+				return
+			}
+			notification := h.candidates[0]
+			h.candidates = h.candidates[1:]
+			h.Unlock()
+			h.candidateFunc(notification)
 		}
-		s := c.states[0]
-		c.states = c.states[1:]
-		c.Unlock()
-		c.NotificationFunc(s)
+	}
+
+	h.candidates = append(h.candidates, c)
+	if !h.running {
+		h.running = true
+		go notify()
 	}
 }
 
-func (a *Agent) candidateRoutine() {
-	for c := range a.chanCandidate {
-		a.onCandidate(c)
+func (h *handlerNotifier) EnqueueSelectedCandidatePair(p *CandidatePair) {
+	h.Lock()
+	defer h.Unlock()
+
+	notify := func() {
+		for {
+			h.Lock()
+			if len(h.selectedCandidatePairs) == 0 {
+				h.running = false
+				h.Unlock()
+				return
+			}
+			notification := h.selectedCandidatePairs[0]
+			h.selectedCandidatePairs = h.selectedCandidatePairs[1:]
+			h.Unlock()
+			h.candidatePairFunc(notification)
+		}
+	}
+
+	h.selectedCandidatePairs = append(h.selectedCandidatePairs, p)
+	if !h.running {
+		h.running = true
+		go notify()
 	}
 }

agent_handlers_test.go

@@ -15,15 +15,15 @@ func TestConnectionStateNotifier(t *testing.T) {
 		report := test.CheckRoutines(t)
 		defer report()
 		updates := make(chan struct{}, 1)
-		c := &connectionStateNotifier{
-			NotificationFunc: func(_ ConnectionState) {
+		c := &handlerNotifier{
+			connectionStateFunc: func(_ ConnectionState) {
 				updates <- struct{}{}
 			},
 		}
 		// Enqueue all updates upfront to ensure that it
 		// doesn't block
 		for i := 0; i < 10000; i++ {
-			c.Enqueue(ConnectionStateNew)
+			c.EnqueueConnectionState(ConnectionStateNew)
 		}
 		done := make(chan struct{})
 		go func() {
@@ -43,8 +43,8 @@ func TestConnectionStateNotifier(t *testing.T) {
 		report := test.CheckRoutines(t)
 		defer report()
 		updates := make(chan ConnectionState)
-		c := &connectionStateNotifier{
-			NotificationFunc: func(cs ConnectionState) {
+		c := &handlerNotifier{
+			connectionStateFunc: func(cs ConnectionState) {
 				updates <- cs
 			},
 		}
@@ -64,7 +64,7 @@ func TestConnectionStateNotifier(t *testing.T) {
 			close(done)
 		}()
 		for i := 0; i < 10000; i++ {
-			c.Enqueue(ConnectionState(i))
+			c.EnqueueConnectionState(ConnectionState(i))
 		}
 		<-done
 	})