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/memory/scoped_vector.h"
  13 #include "base/synchronization/lock.h"
  14 #include "ipc/ipc_sender.h"
  15 #include "ipc/ipc_sync_message.h"
  16 #include "ipc/message_filter.h"
  17
  18 namespace base {
  19 class SingleThreadTaskRunner;
  20 class WaitableEvent;
  21 }
  22
  23 namespace IPC {
  24
  25 // This MessageFilter allows sending synchronous IPC messages from a thread
  26 // other than the listener thread associated with the SyncChannel.  It does not
  27 // support fancy features that SyncChannel does, such as handling recursion or
  28 // receiving messages while waiting for a response.  Note that this object can
  29 // be used to send simultaneous synchronous messages from different threads.
  30 class IPC_EXPORT SyncMessageFilter : public MessageFilter, public Sender {
  31  public:
  32   explicit SyncMessageFilter(base::WaitableEvent* shutdown_event);
  33
  34   // MessageSender implementation.
  35   bool Send(Message* message) override;
  36
  37   // MessageFilter implementation.
  38   void OnFilterAdded(Sender* sender) override;
  39   void OnChannelError() override;
  40   void OnChannelClosing() override;
  41   bool OnMessageReceived(const Message& message) override;
  42
  43  protected:
  44   ~SyncMessageFilter() override;
  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   Sender* sender_;
  53
  54   // The process's main thread.
  55   scoped_refptr<base::SingleThreadTaskRunner> listener_task_runner_;
  56
  57   // The message loop where the Channel lives.
  58   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
  59
  60   typedef std::set<PendingSyncMsg*> PendingSyncMessages;
  61   PendingSyncMessages pending_sync_messages_;
  62
  63   // Messages waiting to be delivered after IO initialization.
  64   ScopedVector<Message> pending_messages_;
  65
  66   // Locks data members above.
  67   base::Lock lock_;
  68
  69   base::WaitableEvent* shutdown_event_;
  70
  71   DISALLOW_COPY_AND_ASSIGN(SyncMessageFilter);
  72 };
  73
  74 }  // namespace IPC
  75
  76 #endif  // IPC_IPC_SYNC_MESSAGE_FILTER_H_