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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef IPC_IPC_SYNC_MESSAGE_FILTER_H_
#define IPC_IPC_SYNC_MESSAGE_FILTER_H_
#include <set>
#include "base/basictypes.h"
#include "base/memory/ref_counted.h"
#include "base/synchronization/lock.h"
#include "ipc/ipc_channel_proxy.h"
#include "ipc/ipc_sync_message.h"
namespace base {
class MessageLoopProxy;
class WaitableEvent;
}
namespace IPC {
// This MessageFilter allows sending synchronous IPC messages from a thread
// other than the listener thread associated with the SyncChannel. It does not
// support fancy features that SyncChannel does, such as handling recursion or
// receiving messages while waiting for a response. Note that this object can
// be used to send simultaneous synchronous messages from different threads.
class IPC_EXPORT SyncMessageFilter : public ChannelProxy::MessageFilter,
public Sender {
public:
explicit SyncMessageFilter(base::WaitableEvent* shutdown_event);
// MessageSender implementation.
virtual bool Send(Message* message) OVERRIDE;
// ChannelProxy::MessageFilter implementation.
virtual void OnFilterAdded(Channel* channel) OVERRIDE;
virtual void OnChannelError() OVERRIDE;
virtual void OnChannelClosing() OVERRIDE;
virtual bool OnMessageReceived(const Message& message) OVERRIDE;
protected:
virtual ~SyncMessageFilter();
private:
void SendOnIOThread(Message* message);
// Signal all the pending sends as done, used in an error condition.
void SignalAllEvents();
// The channel to which this filter was added.
Channel* channel_;
// The process's main thread.
scoped_refptr<base::MessageLoopProxy> listener_loop_;
// The message loop where the Channel lives.
scoped_refptr<base::MessageLoopProxy> io_loop_;
typedef std::set<PendingSyncMsg*> PendingSyncMessages;
PendingSyncMessages pending_sync_messages_;
// Locks data members above.
base::Lock lock_;
base::WaitableEvent* shutdown_event_;
DISALLOW_COPY_AND_ASSIGN(SyncMessageFilter);
};
} // namespace IPC
#endif // IPC_IPC_SYNC_MESSAGE_FILTER_H_