ipc/ipc_sync_message_filter.h

   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 #pragma once
   8
   9 #include <set>
  10
  11 #include "base/basictypes.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/synchronization/lock.h"
  14 #include "ipc/ipc_channel_proxy.h"
  15 #include "ipc/ipc_sync_message.h"
  16
  17 namespace base {
  18 class MessageLoopProxy;
  19 class WaitableEvent;
  20 }
  21
  22 namespace 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.
  29 class IPC_EXPORT SyncMessageFilter : public ChannelProxy::MessageFilter,
  30                                      public Message::Sender {
  31  public:
  32   explicit SyncMessageFilter(base::WaitableEvent* shutdown_event);
  33
  34   // Message::Sender implementation.
  35   virtual bool Send(Message* message) OVERRIDE;
  36
  37   // ChannelProxy::MessageFilter implementation.
  38   virtual void OnFilterAdded(Channel* channel) OVERRIDE;
  39   virtual void OnChannelError() OVERRIDE;
  40   virtual void OnChannelClosing() OVERRIDE;
  41   virtual bool OnMessageReceived(const Message& message) OVERRIDE;
  42
  43  protected:
  44   virtual ~SyncMessageFilter();
  45
  46  private:
  47   void SendOnIOThread(Message* message);
  48   // Signal all the pending sends as done, used in an error condition.
  49   void SignalAllEvents();
  50
  51   // The channel to which this filter was added.
  52   Channel* channel_;
  53
  54   // The process's main thread.
  55   scoped_refptr<base::MessageLoopProxy> listener_loop_;
  56
  57   // The message loop where the Channel lives.
  58   scoped_refptr<base::MessageLoopProxy> io_loop_;
  59
  60   typedef std::set<PendingSyncMsg*> PendingSyncMessages;
  61   PendingSyncMessages pending_sync_messages_;
  62
  63   // Locks data members above.
  64   base::Lock lock_;
  65
  66   base::WaitableEvent* shutdown_event_;
  67
  68   DISALLOW_COPY_AND_ASSIGN(SyncMessageFilter);
  69 };
  70
  71 }  // namespace IPC
  72
  73 #endif  // IPC_IPC_SYNC_MESSAGE_FILTER_H_