Reduce the complexity of WebSocketThrottle's wakeup code

net/websockets/websocket_throttle.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_WEBSOCKETS_WEBSOCKET_THROTTLE_H_
 #define NET_WEBSOCKETS_WEBSOCKET_THROTTLE_H_
 
 #include <deque>
 #include <map>
+#include <set>
 #include <string>
 
 #include "net/base/ip_endpoint.h"
 #include "net/base/net_export.h"
 
 template <typename T> struct DefaultSingletonTraits;
 
 namespace net {
 
 class SocketStream;
 class WebSocketJob;
 
 // SocketStreamThrottle for WebSocket protocol.
 // Implements the client-side requirements in the spec.
 // http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol
 // 4.1 Handshake
 //   1.   If the user agent already has a Web Socket connection to the
 //        remote host (IP address) identified by /host/, even if known by
 //        another name, wait until that connection has been established or
 //        for that connection to have failed.
 class NET_EXPORT_PRIVATE WebSocketThrottle {
  public:
   // Returns the singleton instance.
   static WebSocketThrottle* GetInstance();
 
   // Puts |job| in |queue_| and queues for the destination addresses
   // of |job|.
   // If other job is using the same destination address, set |job| waiting.
-  void PutInQueue(WebSocketJob* job);
+  //
+  // Returns true if successful. If the number of pending jobs will exceed
+  // the limit, does nothing and returns false.
+  bool PutInQueue(WebSocketJob* job);
 
   // Removes |job| from |queue_| and queues for the destination addresses
-  // of |job|.
+  // of |job|, and then wakes up jobs that can now resume establishing a
+  // connection.
   void RemoveFromQueue(WebSocketJob* job);
 
-  // Checks sockets waiting in |queue_| and check the socket is the front of
-  // every queue for the destination addresses of |socket|.
-  // If so, the socket can resume establishing connection, so wake up
-  // the socket.
-  void WakeupSocketIfNecessary();
-
  private:
   typedef std::deque<WebSocketJob*> ConnectingQueue;
-  typedef std::map<IPEndPoint, ConnectingQueue*> ConnectingAddressMap;
+  typedef std::map<IPEndPoint, ConnectingQueue> ConnectingAddressMap;
 
   WebSocketThrottle();
   ~WebSocketThrottle();
   friend struct DefaultSingletonTraits<WebSocketThrottle>;
 
+  // Examines if any of the given jobs can resume establishing a connection. If
+  // for all per-address queues for each resolved addresses
+  // (job->address_list()) of a job, the job is at the front of the queues, the
+  // job can resume establishing a connection, so wakes up the job.
+  void WakeupSocketIfNecessary(
+      const std::set<WebSocketJob*>& wakeup_candidates);
+
   // Key: string of host's address.  Value: queue of sockets for the address.
   ConnectingAddressMap addr_map_;
 
   // Queue of sockets for websockets in opening state.
   ConnectingQueue queue_;
 
   DISALLOW_COPY_AND_ASSIGN(WebSocketThrottle);
 };
 
 }  // namespace net
 
 #endif  // NET_WEBSOCKETS_WEBSOCKET_THROTTLE_H_