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 class SyncChannel;
  25
  26 // This MessageFilter allows sending synchronous IPC messages from a thread
  27 // other than the listener thread associated with the SyncChannel.  It does not
  28 // support fancy features that SyncChannel does, such as handling recursion or
  29 // receiving messages while waiting for a response.  Note that this object can
  30 // be used to send simultaneous synchronous messages from different threads.
  31 class IPC_EXPORT SyncMessageFilter : public MessageFilter, public Sender {
  32  public:
  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(base::WaitableEvent* shutdown_event,
  44                     bool is_channel_send_thread_safe);
  45
  46   ~SyncMessageFilter() override;
  47
  48  private:
  49   friend class SyncChannel;
  50
  51   void set_is_channel_send_thread_safe(bool is_channel_send_thread_safe) {
  52     is_channel_send_thread_safe_ = is_channel_send_thread_safe;
  53   }
  54
  55   void SendOnIOThread(Message* message);
  56   // Signal all the pending sends as done, used in an error condition.
  57   void SignalAllEvents();
  58
  59   // The channel to which this filter was added.
  60   Sender* sender_;
  61
  62   // Indicates if |sender_|'s Send method is thread-safe.
  63   bool is_channel_send_thread_safe_;
  64
  65   // The process's main thread.
  66   scoped_refptr<base::SingleThreadTaskRunner> listener_task_runner_;
  67
  68   // The message loop where the Channel lives.
  69   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
  70
  71   typedef std::set<PendingSyncMsg*> PendingSyncMessages;
  72   PendingSyncMessages pending_sync_messages_;
  73
  74   // Messages waiting to be delivered after IO initialization.
  75   ScopedVector<Message> pending_messages_;
  76
  77   // Locks data members above.
  78   base::Lock lock_;
  79
  80   base::WaitableEvent* shutdown_event_;
  81
  82   DISALLOW_COPY_AND_ASSIGN(SyncMessageFilter);
  83 };
  84
  85 }  // namespace IPC
  86
  87 #endif  // IPC_IPC_SYNC_MESSAGE_FILTER_H_