Remove ports that are not used by any channel after timeout

webrtc/p2p/base/port.cc

Index: webrtc/p2p/base/port.cc
diff --git a/webrtc/p2p/base/port.cc b/webrtc/p2p/base/port.cc
index b6173ebf45768be331c589631f81f9aee8ccbc80..a2dbb9cfa22ed1fe365ece2aa7e1911741f43394 100644
--- a/webrtc/p2p/base/port.cc
+++ b/webrtc/p2p/base/port.cc
@@ -198,6 +198,7 @@ void Port::Construct() {
   network_->SignalTypeChanged.connect(this, &Port::OnNetworkTypeChanged);
   network_cost_ = network_->GetCost();
 
+  thread_->PostDelayed(RTC_FROM_HERE, timeout_delay_, this, MSG_CHECK_DEAD);
   LOG_J(LS_INFO, this) << "Port created with network cost " << network_cost_;
 }
 
@@ -644,13 +645,28 @@ void Port::SendBindingErrorResponse(StunMessage* request,
                        << " to " << addr.ToSensitiveString();
 }
 
+void Port::StartBeingUsed() {
+  is_used_ = true;
+}
+
+void Port::StopBeingUsed() {
+  is_used_ = false;
+  thread_->Post(RTC_FROM_HERE, this, MSG_CHECK_DEAD);
+}
+
 void Port::OnMessage(rtc::Message *pmsg) {
-  ASSERT(pmsg->message_id == MSG_DEAD);
+  ASSERT(pmsg->message_id == MSG_CHECK_DEAD);
   if (dead()) {
     Destroy();
   }
 }
 
+bool Port::dead() const {
+  return !is_used_ && connections_.empty() &&
+         rtc::TimeMillis() - last_time_all_connections_removed_ >=
+             timeout_delay_;
+}
+
 void Port::OnNetworkTypeChanged(const rtc::Network* network) {
   ASSERT(network == network_);
 
@@ -699,12 +715,14 @@ void Port::OnConnectionDestroyed(Connection* conn) {
   connections_.erase(iter);
   HandleConnectionDestroyed(conn);
 
-  // On the controlled side, ports time out after all connections fail.
+  // Ports time out after all connections fail if it is not used by any channel.
   // Note: If a new connection is added after this message is posted, but it
-  // fails and is removed before kPortTimeoutDelay, then this message will
-  // still cause the Port to be destroyed.
-  if (dead()) {
-    thread_->PostDelayed(RTC_FROM_HERE, timeout_delay_, this, MSG_DEAD);
+  // fails and is removed before kPortTimeoutDelay, then the port will not be
+  // destroyed until kPortTimeoutDelay milliseconds after the new connection
+  // is removed.
+  if (connections_.empty()) {
+    last_time_all_connections_removed_ = rtc::TimeMillis();
+    thread_->PostDelayed(RTC_FROM_HERE, timeout_delay_, this, MSG_CHECK_DEAD);
   }
 }