1 files changed, 23 insertions, 1 deletions
diff --git a/JavaScriptCore/wtf/MainThread.cpp b/JavaScriptCore/wtf/MainThread.cpp
index e999094..40a4ae5 100644
--- a/JavaScriptCore/wtf/MainThread.cpp
+++ b/JavaScriptCore/wtf/MainThread.cpp
@@ -39,10 +39,12 @@ namespace WTF {
 struct FunctionWithContext {
     MainThreadFunction* function;
     void* context;
+    ThreadCondition* syncFlag;
 
-    FunctionWithContext(MainThreadFunction* function = 0, void* context = 0)
+    FunctionWithContext(MainThreadFunction* function = 0, void* context = 0, ThreadCondition* syncFlag = 0)
         : function(function)
         , context(context)
+        , syncFlag(syncFlag)
     { 
     }
 };
@@ -92,6 +94,8 @@ void dispatchFunctionsFromMainThread()
         }
 
         invocation.function(invocation.context);
+        if (invocation.syncFlag)
+            invocation.syncFlag->signal();
 
         // If we are running accumulated functions for too long so UI may become unresponsive, we need to
         // yield so the user input can be processed. Otherwise user may not be able to even close the window.
@@ -117,6 +121,24 @@ void callOnMainThread(MainThreadFunction* function, void* context)
         scheduleDispatchFunctionsOnMainThread();
 }
 
+void callOnMainThreadAndWait(MainThreadFunction* function, void* context)
+{
+    ASSERT(function);
+
+    if (isMainThread()) {
+        function(context);
+        return;
+    }
+
+    ThreadCondition syncFlag;
+    Mutex& functionQueueMutex = mainThreadFunctionQueueMutex();
+    MutexLocker locker(functionQueueMutex);
+    functionQueue().append(FunctionWithContext(function, context, &syncFlag));
+    if (functionQueue().size() == 1)
+        scheduleDispatchFunctionsOnMainThread();
+    syncFlag.wait(functionQueueMutex);
+}
+
 void setMainThreadCallbacksPaused(bool paused)
 {
     ASSERT(isMainThread());