JavaScriptCore-903.tar.gz

[apple/javascriptcore.git] / wtf / MainThread.cpp

diff --git a/wtf/MainThread.cpp b/wtf/MainThread.cpp
index c7a6caa34451e3ef0aa314d76fea066acc9e1a49..3229e5b06f315b0c2ec5b4cc860984bca930560a 100644 (file)
--- a/wtf/MainThread.cpp
+++ b/wtf/MainThread.cpp
@@ -29,9 +29,16 @@
 #include "config.h"
 #include "MainThread.h"
 
+#include "CurrentTime.h"
+#include "Deque.h"
 #include "StdLibExtras.h"
 #include "Threading.h"
-#include "Vector.h"
+
+#include <wtf/iphone/WebCoreThread.h>
+
+#if PLATFORM(CHROMIUM)
+#error Chromium uses a different main thread implementation
+#endif
 
 namespace WTF {
 
@@ -46,13 +53,30 @@ struct FunctionWithContext {
         , syncFlag(syncFlag)
     { 
     }
+    bool operator == (const FunctionWithContext& o)
+    {
+        return function == o.function
+            && context == o.context
+            && syncFlag == o.syncFlag;
+    }
+};
+
+class FunctionWithContextFinder {
+public:
+    FunctionWithContextFinder(const FunctionWithContext& m) : m(m) {}
+    bool operator() (FunctionWithContext& o) { return o == m; }
+    FunctionWithContext m;
 };
 
-typedef Vector<FunctionWithContext> FunctionQueue;
+
+typedef Deque<FunctionWithContext> FunctionQueue;
 
 static bool callbacksPaused; // This global variable is only accessed from main thread.
+#if !PLATFORM(MAC) && !PLATFORM(QT)
+static ThreadIdentifier mainThreadIdentifier;
+#endif
 
-Mutex& mainThreadFunctionQueueMutex()
+static Mutex& mainThreadFunctionQueueMutex()
 {
     DEFINE_STATIC_LOCAL(Mutex, staticMutex, ());
     return staticMutex;
@@ -64,13 +88,54 @@ static FunctionQueue& functionQueue()
     return staticFunctionQueue;
 }
 
-#if !PLATFORM(WIN)
+
+#if !PLATFORM(MAC)
+
 void initializeMainThread()
+{
+    static bool initializedMainThread;
+    if (initializedMainThread)
+        return;
+    initializedMainThread = true;
+
+#if !PLATFORM(QT)
+    mainThreadIdentifier = currentThread();
+#endif
+
+    mainThreadFunctionQueueMutex();
+    initializeMainThreadPlatform();
+}
+
+#else
+
+static pthread_once_t initializeMainThreadKeyOnce = PTHREAD_ONCE_INIT;
+
+static void initializeMainThreadOnce()
 {
     mainThreadFunctionQueueMutex();
+    initializeMainThreadPlatform();
+}
+
+void initializeMainThread()
+{
+    pthread_once(&initializeMainThreadKeyOnce, initializeMainThreadOnce);
+}
+
+static void initializeMainThreadToProcessMainThreadOnce()
+{
+    mainThreadFunctionQueueMutex();
+    initializeMainThreadToProcessMainThreadPlatform();
+}
+
+void initializeMainThreadToProcessMainThread()
+{
+    pthread_once(&initializeMainThreadKeyOnce, initializeMainThreadToProcessMainThreadOnce);
 }
 #endif
 
+// 0.1 sec delays in UI is approximate threshold when they become noticeable. Have a limit that's half of that.
+static const double maxRunLoopSuspensionTime = 0.05;
+
 void dispatchFunctionsFromMainThread()
 {
     ASSERT(isMainThread());
@@ -78,30 +143,45 @@ void dispatchFunctionsFromMainThread()
     if (callbacksPaused)
         return;
 
-    FunctionQueue queueCopy;
-    {
-        MutexLocker locker(mainThreadFunctionQueueMutex());
-        queueCopy.swap(functionQueue());
-    }
+    double startTime = currentTime();
+
+    FunctionWithContext invocation;
+    while (true) {
+        {
+            MutexLocker locker(mainThreadFunctionQueueMutex());
+            if (!functionQueue().size())
+                break;
+            invocation = functionQueue().takeFirst();
+        }
 
-    for (unsigned i = 0; i < queueCopy.size(); ++i) {
-        FunctionWithContext& invocation = queueCopy[i];
         invocation.function(invocation.context);
-        if (invocation.syncFlag)
+        if (invocation.syncFlag) {
+            MutexLocker locker(mainThreadFunctionQueueMutex());
             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.
+        // This code has effect only in case the scheduleDispatchFunctionsOnMainThread() is implemented in a way that
+        // allows input events to be processed before we are back here.
+        if (currentTime() - startTime > maxRunLoopSuspensionTime) {
+            scheduleDispatchFunctionsOnMainThread();
+            break;
+        }
     }
 }
 
 void callOnMainThread(MainThreadFunction* function, void* context)
 {
     ASSERT(function);
-
+    bool needToSchedule = false;
     {
         MutexLocker locker(mainThreadFunctionQueueMutex());
+        needToSchedule = functionQueue().size() == 0;
         functionQueue().append(FunctionWithContext(function, context));
     }
-
-    scheduleDispatchFunctionsOnMainThread();
+    if (needToSchedule)
+        scheduleDispatchFunctionsOnMainThread();
 }
 
 void callOnMainThreadAndWait(MainThreadFunction* function, void* context)
@@ -114,21 +194,35 @@ void callOnMainThreadAndWait(MainThreadFunction* function, void* context)
     }
 
     ThreadCondition syncFlag;
-    Mutex conditionMutex;
+    Mutex& functionQueueMutex = mainThreadFunctionQueueMutex();
+    MutexLocker locker(functionQueueMutex);
+    functionQueue().append(FunctionWithContext(function, context, &syncFlag));
+    if (functionQueue().size() == 1)
+        scheduleDispatchFunctionsOnMainThread();
+    syncFlag.wait(functionQueueMutex);
+}
 
-    {
-        MutexLocker locker(mainThreadFunctionQueueMutex());
-        functionQueue().append(FunctionWithContext(function, context, &syncFlag));
-        conditionMutex.lock();
-    }
+void cancelCallOnMainThread(MainThreadFunction* function, void* context)
+{
+    ASSERT(function);
+
+    MutexLocker locker(mainThreadFunctionQueueMutex());
+
+    FunctionWithContextFinder pred(FunctionWithContext(function, context));
 
-    scheduleDispatchFunctionsOnMainThread();
-    syncFlag.wait(conditionMutex);
+    while (true) {
+        // We must redefine 'i' each pass, because the itererator's operator= 
+        // requires 'this' to be valid, and remove() invalidates all iterators
+        FunctionQueue::iterator i(functionQueue().findIf(pred));
+        if (i == functionQueue().end())
+            break;
+        functionQueue().remove(i);
+    }
 }
 
 void setMainThreadCallbacksPaused(bool paused)
 {
-    ASSERT(isMainThread());
+    ASSERT((isMainThread() || pthread_main_np()) && WebCoreWebThreadIsLockedOrDisabled());
 
     if (callbacksPaused == paused)
         return;
@@ -139,4 +233,11 @@ void setMainThreadCallbacksPaused(bool paused)
         scheduleDispatchFunctionsOnMainThread();
 }
 
+#if !PLATFORM(MAC) && !PLATFORM(QT) && !PLATFORM(BREWMP)
+bool isMainThread()
+{
+    return currentThread() == mainThreadIdentifier;
+}
+#endif
+
 } // namespace WTF