Prune connections based on network name.

webrtc/p2p/base/p2ptransportchannel.cc

Index: webrtc/p2p/base/p2ptransportchannel.cc
diff --git a/webrtc/p2p/base/p2ptransportchannel.cc b/webrtc/p2p/base/p2ptransportchannel.cc
index 6bcf0d7d2bfb09e9548501dccfde4e2ba249a5bd..0458baf3ef46a0b9d9894ae87cbc6d395ffc2f98 100644
--- a/webrtc/p2p/base/p2ptransportchannel.cc
+++ b/webrtc/p2p/base/p2ptransportchannel.cc
@@ -1306,34 +1306,35 @@ void P2PTransportChannel::SortConnectionsAndUpdateState() {
 }
 
 void P2PTransportChannel::PruneConnections() {
-  // We can prune any connection for which there is a connected, writable
-  // connection on the same network with better or equal priority.  We leave
-  // those with better priority just in case they become writable later (at
-  // which point, we would prune out the current selected connection).  We leave
-  // connections on other networks because they may not be using the same
-  // resources and they may represent very distinct paths over which we can
-  // switch. If the |premier| connection is not connected, we may be
-  // reconnecting a TCP connection and temporarily do not prune connections in
-  // this network. See the big comment in CompareConnectionStates.
-
-  // Get a list of the networks that we are using.
-  std::set<rtc::Network*> networks;
-  for (const Connection* conn : connections_) {
-    networks.insert(conn->port()->Network());
-  }
-  for (rtc::Network* network : networks) {
-    Connection* premier = GetBestConnectionOnNetwork(network);
-    // Do not prune connections if the current selected connection is weak on
-    // this network. Otherwise, it may delete connections prematurely.
-    if (!premier || premier->weak()) {
-      continue;
-    }
-
-    for (Connection* conn : connections_) {
-      if ((conn != premier) && (conn->port()->Network() == network) &&
-          (CompareConnectionCandidates(premier, conn) >= 0)) {
-        conn->Prune();
-      }
+  // We can prune any connection for which there is a connected, writable,
+  // and receiving connection with the same network name with better or equal
+  // priority. We leave those with better priority just in case they become
+  // writable later (at which point, we would prune out the current selected
+  // connection). We leave connections on other networks because they may not
+  // be using the same resources and they may represent very distinct paths
+  // over which we can switch. If the |premier| connection is not connected,
+  // we may be reconnecting a TCP connection and temporarily do not prune
+  // connections in this network. See the big comment in
+  // CompareConnectionStates.
+
+  std::map<std::string, Connection*> premier_connection_by_network_name;
+  if (selected_connection_) {
+    // |selected_connection_| is always a premier connection.
+    const std::string& network_name =
+        selected_connection_->port()->Network()->name();
+    premier_connection_by_network_name[network_name] = selected_connection_;
+  }
+  for (Connection* conn : connections_) {
+    const std::string& network_name = conn->port()->Network()->name();
+    Connection* premier = premier_connection_by_network_name[network_name];
+    // Since the connections are sorted, the first one with a given network name
+    // is the premier connection for the network name.
+    // |premier| might be equal to |conn| if this is the selected connection.
+    if (premier == nullptr) {
+      premier_connection_by_network_name[network_name] = conn;
+    } else if (premier != conn && !premier->weak() &&
+               CompareConnectionCandidates(premier, conn) >= 0) {
+      conn->Prune();
     }
   }
 }
@@ -1471,26 +1472,6 @@ bool P2PTransportChannel::ReadyToSend(Connection* connection) const {
           PresumedWritable(connection));
 }
 
-// If we have a selected connection, return it, otherwise return top one in the
-// list (later we will mark it best).
-Connection* P2PTransportChannel::GetBestConnectionOnNetwork(
-    rtc::Network* network) const {
-  // If the selected connection is on this network, then it wins.
-  if (selected_connection_ &&
-      (selected_connection_->port()->Network() == network)) {
-    return selected_connection_;
-  }
-
-  // Otherwise, we return the top-most in sorted order.
-  for (size_t i = 0; i < connections_.size(); ++i) {
-    if (connections_[i]->port()->Network() == network) {
-      return connections_[i];
-    }
-  }
-
-  return NULL;
-}
-
 // Handle any queued up requests
 void P2PTransportChannel::OnMessage(rtc::Message *pmsg) {
   switch (pmsg->message_id) {