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
   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
  17 namespace base {
  18 class SingleThreadTaskRunner;
  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 MessageFilter, public Sender {
  30  public:
  31   explicit SyncMessageFilter(base::WaitableEvent* shutdown_event);
  32
  33   // MessageSender implementation.
  34   bool Send(Message* message) override;
  35
  36   // MessageFilter implementation.
  37   void OnFilterAdded(Sender* sender) override;
  38   void OnChannelError() override;
  39   void OnChannelClosing() override;
  40   bool OnMessageReceived(const Message& message) override;
  41
  42  protected:
  43   ~SyncMessageFilter() override;
  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::SingleThreadTaskRunner> listener_task_runner_;
  55
  56   // The message loop where the Channel lives.
  57   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
  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_