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/*
* Copyright (C) 2008 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef MessageQueue_h
#define MessageQueue_h
#include <wtf/Assertions.h>
#include <wtf/Deque.h>
#include <wtf/Noncopyable.h>
#include <wtf/Threading.h>
namespace WTF {
template<typename DataType>
class MessageQueue : Noncopyable {
public:
MessageQueue() : m_killed(false) {}
void append(const DataType&);
void prepend(const DataType&);
bool waitForMessage(DataType&);
void kill();
bool tryGetMessage(DataType&);
bool killed() const;
// The result of isEmpty() is only valid if no other thread is manipulating the queue at the same time.
bool isEmpty();
private:
mutable Mutex m_mutex;
ThreadCondition m_condition;
Deque<DataType> m_queue;
bool m_killed;
};
template<typename DataType>
inline void MessageQueue<DataType>::append(const DataType& message)
{
MutexLocker lock(m_mutex);
m_queue.append(message);
m_condition.signal();
}
template<typename DataType>
inline void MessageQueue<DataType>::prepend(const DataType& message)
{
MutexLocker lock(m_mutex);
m_queue.prepend(message);
m_condition.signal();
}
template<typename DataType>
inline bool MessageQueue<DataType>::waitForMessage(DataType& result)
{
MutexLocker lock(m_mutex);
while (!m_killed && m_queue.isEmpty())
m_condition.wait(m_mutex);
if (m_killed)
return false;
ASSERT(!m_queue.isEmpty());
result = m_queue.first();
m_queue.removeFirst();
return true;
}
template<typename DataType>
inline bool MessageQueue<DataType>::tryGetMessage(DataType& result)
{
MutexLocker lock(m_mutex);
if (m_killed)
return false;
if (m_queue.isEmpty())
return false;
result = m_queue.first();
m_queue.removeFirst();
return true;
}
template<typename DataType>
inline bool MessageQueue<DataType>::isEmpty()
{
MutexLocker lock(m_mutex);
if (m_killed)
return true;
return m_queue.isEmpty();
}
template<typename DataType>
inline void MessageQueue<DataType>::kill()
{
MutexLocker lock(m_mutex);
m_killed = true;
m_condition.broadcast();
}
template<typename DataType>
inline bool MessageQueue<DataType>::killed() const
{
MutexLocker lock(m_mutex);
return m_killed;
}
}
using WTF::MessageQueue;
#endif // MessageQueue_h
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