1// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef NET_WEBSOCKETS_WEBSOCKET_THROTTLE_H_
6#define NET_WEBSOCKETS_WEBSOCKET_THROTTLE_H_
7
8#include <deque>
9#include <map>
10#include <set>
11#include <string>
12
13#include "net/base/ip_endpoint.h"
14#include "net/base/net_export.h"
15
16template <typename T> struct DefaultSingletonTraits;
17
18namespace net {
19
20class SocketStream;
21class WebSocketJob;
22
23// SocketStreamThrottle for WebSocket protocol.
24// Implements the client-side requirements in the spec.
25// http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol
26// 4.1 Handshake
27//   1.   If the user agent already has a Web Socket connection to the
28//        remote host (IP address) identified by /host/, even if known by
29//        another name, wait until that connection has been established or
30//        for that connection to have failed.
31class NET_EXPORT_PRIVATE WebSocketThrottle {
32 public:
33  // Returns the singleton instance.
34  static WebSocketThrottle* GetInstance();
35
36  // Puts |job| in |queue_| and queues for the destination addresses
37  // of |job|.
38  // If other job is using the same destination address, set |job| waiting.
39  //
40  // Returns true if successful. If the number of pending jobs will exceed
41  // the limit, does nothing and returns false.
42  bool PutInQueue(WebSocketJob* job);
43
44  // Removes |job| from |queue_| and queues for the destination addresses
45  // of |job|, and then wakes up jobs that can now resume establishing a
46  // connection.
47  void RemoveFromQueue(WebSocketJob* job);
48
49 private:
50  typedef std::deque<WebSocketJob*> ConnectingQueue;
51  typedef std::map<IPEndPoint, ConnectingQueue> ConnectingAddressMap;
52
53  WebSocketThrottle();
54  ~WebSocketThrottle();
55  friend struct DefaultSingletonTraits<WebSocketThrottle>;
56
57  // Examines if any of the given jobs can resume establishing a connection. If
58  // for all per-address queues for each resolved addresses
59  // (job->address_list()) of a job, the job is at the front of the queues, the
60  // job can resume establishing a connection, so wakes up the job.
61  void WakeupSocketIfNecessary(
62      const std::set<WebSocketJob*>& wakeup_candidates);
63
64  // Key: string of host's address.  Value: queue of sockets for the address.
65  ConnectingAddressMap addr_map_;
66
67  // Queue of sockets for websockets in opening state.
68  ConnectingQueue queue_;
69
70  DISALLOW_COPY_AND_ASSIGN(WebSocketThrottle);
71};
72
73}  // namespace net
74
75#endif  // NET_WEBSOCKETS_WEBSOCKET_THROTTLE_H_
76