1// Copyright (c) 2012 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 IPC_IPC_SYNC_MESSAGE_FILTER_H_
6#define IPC_IPC_SYNC_MESSAGE_FILTER_H_
7
8#include <set>
9
10#include "base/basictypes.h"
11#include "base/memory/ref_counted.h"
12#include "base/synchronization/lock.h"
13#include "ipc/ipc_sender.h"
14#include "ipc/ipc_sync_message.h"
15#include "ipc/message_filter.h"
16
17namespace base {
18class MessageLoopProxy;
19class WaitableEvent;
20}
21
22namespace IPC {
23
24// This MessageFilter allows sending synchronous IPC messages from a thread
25// other than the listener thread associated with the SyncChannel.  It does not
26// support fancy features that SyncChannel does, such as handling recursion or
27// receiving messages while waiting for a response.  Note that this object can
28// be used to send simultaneous synchronous messages from different threads.
29class IPC_EXPORT SyncMessageFilter : public MessageFilter, public Sender {
30 public:
31  explicit SyncMessageFilter(base::WaitableEvent* shutdown_event);
32
33  // MessageSender implementation.
34  virtual bool Send(Message* message) OVERRIDE;
35
36  // MessageFilter implementation.
37  virtual void OnFilterAdded(Sender* sender) OVERRIDE;
38  virtual void OnChannelError() OVERRIDE;
39  virtual void OnChannelClosing() OVERRIDE;
40  virtual bool OnMessageReceived(const Message& message) OVERRIDE;
41
42 protected:
43  virtual ~SyncMessageFilter();
44
45 private:
46  void SendOnIOThread(Message* message);
47  // Signal all the pending sends as done, used in an error condition.
48  void SignalAllEvents();
49
50  // The channel to which this filter was added.
51  Sender* sender_;
52
53  // The process's main thread.
54  scoped_refptr<base::MessageLoopProxy> listener_loop_;
55
56  // The message loop where the Channel lives.
57  scoped_refptr<base::MessageLoopProxy> io_loop_;
58
59  typedef std::set<PendingSyncMsg*> PendingSyncMessages;
60  PendingSyncMessages pending_sync_messages_;
61
62  // Locks data members above.
63  base::Lock lock_;
64
65  base::WaitableEvent* shutdown_event_;
66
67  DISALLOW_COPY_AND_ASSIGN(SyncMessageFilter);
68};
69
70}  // namespace IPC
71
72#endif  // IPC_IPC_SYNC_MESSAGE_FILTER_H_
73