1 files changed, 13 insertions, 1 deletions
diff --git a/src/3rdparty/webkit/JavaScriptCore/wtf/MessageQueue.h b/src/3rdparty/webkit/JavaScriptCore/wtf/MessageQueue.h
index 9549f37..7721dba 100644
--- a/src/3rdparty/webkit/JavaScriptCore/wtf/MessageQueue.h
+++ b/src/3rdparty/webkit/JavaScriptCore/wtf/MessageQueue.h
@@ -47,9 +47,10 @@ namespace WTF {
     template<typename DataType>
     class MessageQueue : Noncopyable {
     public:
-        MessageQueue() : m_killed(false) {}
+        MessageQueue() : m_killed(false) { }
         
         void append(const DataType&);
+        bool appendAndCheckEmpty(const DataType&);
         void prepend(const DataType&);
         bool waitForMessage(DataType&);
         template<typename Predicate>
@@ -81,6 +82,17 @@ namespace WTF {
         m_condition.signal();
     }
 
+    // Returns true if the queue was empty before the item was added.
+    template<typename DataType>
+    inline bool MessageQueue<DataType>::appendAndCheckEmpty(const DataType& message)
+    {
+        MutexLocker lock(m_mutex);
+        bool wasEmpty = m_queue.isEmpty();
+        m_queue.append(message);
+        m_condition.signal();
+        return wasEmpty;
+    }
+
     template<typename DataType>
     inline void MessageQueue<DataType>::prepend(const DataType& message)
     {