JavaScriptCore-521.tar.gz

[apple/javascriptcore.git] / wtf / MessageQueue.h

diff --git a/wtf/MessageQueue.h b/wtf/MessageQueue.h
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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 {
+
+    enum MessageQueueWaitResult {
+        MessageQueueTerminated,       // Queue was destroyed while waiting for message.
+        MessageQueueTimeout,          // Timeout was specified and it expired.
+        MessageQueueMessageReceived,  // A message was successfully received and returned.
+    };
+
+    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;
+
+        // 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 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;
+// MessageQueueWaitResult enum and all its values.
+using WTF::MessageQueueWaitResult;
+using WTF::MessageQueueTerminated;
+using WTF::MessageQueueTimeout;
+using WTF::MessageQueueMessageReceived;
+
+#endif // MessageQueue_h