WebKit side of merge from r41149 to r41181.

JavaScriptCore/wtf/MessageQueue.h

Index: JavaScriptCore/wtf/MessageQueue.h
===================================================================
--- JavaScriptCore/wtf/MessageQueue.h	(revision 10232)
+++ JavaScriptCore/wtf/MessageQueue.h	(working copy)
@@ -30,6 +30,7 @@
 #ifndef MessageQueue_h
 #define MessageQueue_h
 
+#include <limits>
 #include <wtf/Assertions.h>
 #include <wtf/Deque.h>
 #include <wtf/Noncopyable.h>
@@ -52,8 +53,7 @@
         void prepend(const DataType&);
         bool waitForMessage(DataType&);
         template<typename Predicate>
-        MessageQueueWaitResult waitForMessageFiltered(DataType&, Predicate&);
-        MessageQueueWaitResult waitForMessageTimed(DataType&, double absoluteTime);
+        MessageQueueWaitResult waitForMessageFilteredWithTimeout(DataType&, Predicate&, double absoluteTime);
         void kill();
 
         bool tryGetMessage(DataType&);
@@ -62,7 +62,11 @@
         // The result of isEmpty() is only valid if no other thread is manipulating the queue at the same time.
         bool isEmpty();
 
+        static double infiniteTime() { return std::numeric_limits<double>::max(); }
+
     private:
+        static bool alwaysTruePredicate(DataType&) { return true; }
+
         mutable Mutex m_mutex;
         ThreadCondition m_condition;
         Deque<DataType> m_queue;
@@ -88,57 +92,33 @@
     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;
+        MessageQueueWaitResult exitReason = waitForMessageFilteredWithTimeout(result, MessageQueue<DataType>::alwaysTruePredicate, infiniteTime());
+        ASSERT(exitReason == MessageQueueTerminated || exitReason == MessageQueueMessageReceived);
+        return exitReason == MessageQueueMessageReceived;
     }
 
     template<typename DataType>
     template<typename Predicate>
-    inline MessageQueueWaitResult MessageQueue<DataType>::waitForMessageFiltered(DataType& result, Predicate& predicate)
+    inline MessageQueueWaitResult MessageQueue<DataType>::waitForMessageFilteredWithTimeout(DataType& result, Predicate& predicate, double absoluteTime)
     {
         MutexLocker lock(m_mutex);
-
-        DequeConstIterator<DataType> found = m_queue.end();
-        while (!m_killed && (found = m_queue.findIf(predicate)) == m_queue.end())
-            m_condition.wait(m_mutex);
-
-        if (m_killed)
-            return MessageQueueTerminated;
-
-        ASSERT(found != m_queue.end());
-        result = *found;
-        m_queue.remove(found);
-        return MessageQueueMessageReceived;
-    }
-
-    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())
+        DequeConstIterator<DataType> found = m_queue.end();
+        while (!m_killed && !timedOut && (found = m_queue.findIf(predicate)) == m_queue.end())
             timedOut = !m_condition.timedWait(m_mutex, absoluteTime);
 
+        ASSERT(!timedOut || absoluteTime != infiniteTime());
+
         if (m_killed)
             return MessageQueueTerminated;
 
         if (timedOut)
             return MessageQueueTimeout;
 
-        ASSERT(!m_queue.isEmpty());
-        result = m_queue.first();
-        m_queue.removeFirst();
+        ASSERT(found != m_queue.end());
+        result = *found;
+        m_queue.remove(found);
         return MessageQueueMessageReceived;
     }