#ifndef MessageQueue_h
#define MessageQueue_h
#include <wtf/Assertions.h>
#include <wtf/Deque.h>
#include <wtf/Noncopyable.h>
#include <wtf/Threading.h>
namespace WTF {
enum MessageQueueWaitResult {
MessageQueueTerminated, MessageQueueTimeout, MessageQueueMessageReceived, };
template<typename DataType>
class MessageQueue : Noncopyable {
public:
MessageQueue() : m_killed(false) {}
void append(const DataType&);
void prepend(const DataType&);
bool waitForMessage(DataType&);
MessageQueueWaitResult waitForMessageTimed(DataType&, double absoluteTime);
void kill();
bool tryGetMessage(DataType&);
bool killed() const;
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 MessageQueueWaitResult MessageQueue<DataType>::waitForMessageTimed(DataType& result, double absoluteTime)
{
MutexLocker lock(m_mutex);
bool timedOut = false;
while (!m_killed && !timedOut && m_queue.isEmpty())
timedOut = !m_condition.timedWait(m_mutex, absoluteTime);
if (m_killed)
return MessageQueueTerminated;
if (timedOut)
return MessageQueueTimeout;
ASSERT(!m_queue.isEmpty());
result = m_queue.first();
m_queue.removeFirst();
return MessageQueueMessageReceived;
}
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;
using WTF::MessageQueueWaitResult;
using WTF::MessageQueueTerminated;
using WTF::MessageQueueTimeout;
using WTF::MessageQueueMessageReceived;
#endif // MessageQueue_h