[WebSocket] Task creation should be separated from task posting.

Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp

 /*
  * Copyright (C) 2011, 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 325 matching lines @@
 
 static void workerGlobalScopeDidConnect(ExecutionContext* context, PassRefPtrWillBeRawPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper, const String& subprotocol, const String& extensions)
 {
     ASSERT_UNUSED(context, context->isWorkerGlobalScope());
     workerClientWrapper->didConnect(subprotocol, extensions);
 }
 
 void WorkerThreadableWebSocketChannel::Peer::didConnect(const String& subprotocol, const String& extensions)
 {
     ASSERT(isMainThread());
-    m_loaderProxy.postTaskToWorkerGlobalScope(createCallbackTask(&workerGlobalScopeDidConnect, m_workerClientWrapper.get(), subprotocol, extensions));
+    // It is important to seprate task creation from posting
+    // the task. See the above comment.
+    OwnPtr<ExecutionContextTask> task = createCallbackTask(&workerGlobalScopeDidConnect, m_workerClientWrapper.get(), subprotocol, extensions);
+    m_loaderProxy.postTaskToWorkerGlobalScope(task.release());
 }
 
 static void workerGlobalScopeDidReceiveMessage(ExecutionContext* context, PassRefPtrWillBeRawPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper, const String& message)
 {
     ASSERT_UNUSED(context, context->isWorkerGlobalScope());
     workerClientWrapper->didReceiveMessage(message);
 }
 
 void WorkerThreadableWebSocketChannel::Peer::didReceiveMessage(const String& message)
 {
     ASSERT(isMainThread());
-    m_loaderProxy.postTaskToWorkerGlobalScope(createCallbackTask(&workerGlobalScopeDidReceiveMessage, m_workerClientWrapper.get(), message));
+    // It is important to seprate task creation from posting
+    // the task. See the above comment.
+    OwnPtr<ExecutionContextTask> task = createCallbackTask(&workerGlobalScopeDidReceiveMessage, m_workerClientWrapper.get(), message);
+    m_loaderProxy.postTaskToWorkerGlobalScope(task.release());
 }
 
 static void workerGlobalScopeDidReceiveBinaryData(ExecutionContext* context, PassRefPtrWillBeRawPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper, PassOwnPtr<Vector<char> > binaryData)
 {
     ASSERT_UNUSED(context, context->isWorkerGlobalScope());
     workerClientWrapper->didReceiveBinaryData(binaryData);
 }
 
 void WorkerThreadableWebSocketChannel::Peer::didReceiveBinaryData(PassOwnPtr<Vector<char> > binaryData)
 {
     ASSERT(isMainThread());
-    m_loaderProxy.postTaskToWorkerGlobalScope(createCallbackTask(&workerGlobalScopeDidReceiveBinaryData, m_workerClientWrapper.get(), binaryData));
+    // It is important to seprate task creation from posting
+    // the task. See the above comment.
+    OwnPtr<ExecutionContextTask> task = createCallbackTask(&workerGlobalScopeDidReceiveBinaryData, m_workerClientWrapper.get(), binaryData);
+    m_loaderProxy.postTaskToWorkerGlobalScope(task.release());
 }
 
 static void workerGlobalScopeDidConsumeBufferedAmount(ExecutionContext* context, PassRefPtrWillBeRawPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper, unsigned long consumed)
 {
     ASSERT_UNUSED(context, context->isWorkerGlobalScope());
     workerClientWrapper->didConsumeBufferedAmount(consumed);
 }
 
 void WorkerThreadableWebSocketChannel::Peer::didConsumeBufferedAmount(unsigned long consumed)
 {
     ASSERT(isMainThread());
-    m_loaderProxy.postTaskToWorkerGlobalScope(createCallbackTask(&workerGlobalScopeDidConsumeBufferedAmount, m_workerClientWrapper.get(), consumed));
+    // It is important to seprate task creation from posting
+    // the task. See the above comment.
+    OwnPtr<ExecutionContextTask> task = createCallbackTask(&workerGlobalScopeDidConsumeBufferedAmount, m_workerClientWrapper.get(), consumed);
+    m_loaderProxy.postTaskToWorkerGlobalScope(task.release());
 }
 
 static void workerGlobalScopeDidStartClosingHandshake(ExecutionContext* context, PassRefPtrWillBeRawPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper)
 {
     ASSERT_UNUSED(context, context->isWorkerGlobalScope());
     workerClientWrapper->didStartClosingHandshake();
 }
 
 void WorkerThreadableWebSocketChannel::Peer::didStartClosingHandshake()
 {
     ASSERT(isMainThread());
-    m_loaderProxy.postTaskToWorkerGlobalScope(createCallbackTask(&workerGlobalScopeDidStartClosingHandshake, m_workerClientWrapper.get()));
+    // It is important to seprate task creation from posting
+    // the task. See the above comment.
+    OwnPtr<ExecutionContextTask> task = createCallbackTask(&workerGlobalScopeDidStartClosingHandshake, m_workerClientWrapper.get());
+    m_loaderProxy.postTaskToWorkerGlobalScope(task.release());
 }
 
 static void workerGlobalScopeDidClose(ExecutionContext* context, PassRefPtrWillBeRawPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper, WebSocketChannelClient::ClosingHandshakeCompletionStatus closingHandshakeCompletion, unsigned short code, const String& reason)
 {
     ASSERT_UNUSED(context, context->isWorkerGlobalScope());
     workerClientWrapper->didClose(closingHandshakeCompletion, code, reason);
 }
 
 void WorkerThreadableWebSocketChannel::Peer::didClose(ClosingHandshakeCompletionStatus closingHandshakeCompletion, unsigned short code, const String& reason)
 {
     ASSERT(isMainThread());
     m_mainWebSocketChannel = nullptr;
-    m_loaderProxy.postTaskToWorkerGlobalScope(createCallbackTask(&workerGlobalScopeDidClose, m_workerClientWrapper.get(), closingHandshakeCompletion, code, reason));
+    // It is important to seprate task creation from posting
+    // the task. See the above comment.
+    OwnPtr<ExecutionContextTask> task = createCallbackTask(&workerGlobalScopeDidClose, m_workerClientWrapper.get(), closingHandshakeCompletion, code, reason);
+    m_loaderProxy.postTaskToWorkerGlobalScope(task.release());
 }
 
 static void workerGlobalScopeDidReceiveMessageError(ExecutionContext* context, PassRefPtrWillBeRawPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper)
 {
     ASSERT_UNUSED(context, context->isWorkerGlobalScope());
     workerClientWrapper->didReceiveMessageError();
 }
 
 void WorkerThreadableWebSocketChannel::Peer::didReceiveMessageError()
 {
     ASSERT(isMainThread());
-    m_loaderProxy.postTaskToWorkerGlobalScope(createCallbackTask(&workerGlobalScopeDidReceiveMessageError, m_workerClientWrapper.get()));
+    // It is important to seprate task creation from posting
+    // the task. See the above comment.
+    OwnPtr<ExecutionContextTask> task = createCallbackTask(&workerGlobalScopeDidReceiveMessageError, m_workerClientWrapper.get());
+    m_loaderProxy.postTaskToWorkerGlobalScope(task.release());
 }
 
 void WorkerThreadableWebSocketChannel::Peer::trace(Visitor* visitor)
 {
     visitor->trace(m_workerClientWrapper);
     visitor->trace(m_mainWebSocketChannel);
     visitor->trace(m_syncHelper);
     WebSocketChannelClient::trace(visitor);
 }
 
@@ skipping 18 matching lines @@
     RefPtr<WeakReference<Peer> > reference = WeakReference<Peer>::createUnbound();
     m_peer = WeakPtr<Peer>(reference);
 #endif
 
     RefPtrWillBeRawPtr<ThreadableWebSocketChannelSyncHelper> syncHelper = ThreadableWebSocketChannelSyncHelper::create(adoptPtr(blink::Platform::current()->createWaitableEvent()));
     // This pointer is guaranteed to be valid until we call terminatePeer.
     m_syncHelper = syncHelper.get();
 
     RefPtrWillBeRawPtr<Bridge> protect(this);
 #if ENABLE(OILPAN)
-    if (!waitForMethodCompletion(createCallbackTask(&Peer::initialize, &m_peer, AllowCrossThreadAccess(&m_loaderProxy), m_workerClientWrapper.get(), sourceURL, lineNumber, syncHelper.get()))) {
+    // In order to assure all temporary objects to be destroyed before
+    // posting the task, we separate task creation and posting.
+    // In other words, it is dangerous to have a complicated expression
+    // as a waitForMethodCompletion argument.
+    OwnPtr<ExecutionContextTask> task = createCallbackTask(&Peer::initialize, &m_peer, AllowCrossThreadAccess(&m_loaderProxy), m_workerClientWrapper.get(), sourceURL, lineNumber, syncHelper.get());
 #else
-    if (!waitForMethodCompletion(createCallbackTask(&Peer::initialize, reference, AllowCrossThreadAccess(&m_loaderProxy), m_workerClientWrapper.get(), sourceURL, lineNumber, syncHelper.get()))) {
+    // See the above comment.
+    OwnPtr<ExecutionContextTask> task = createCallbackTask(&Peer::initialize, reference, AllowCrossThreadAccess(&m_loaderProxy), m_workerClientWrapper.get(), sourceURL, lineNumber, syncHelper.get());
 #endif
+    if (!waitForMethodCompletion(task.release())) {
         // The worker thread has been signalled to shutdown before method completion.
         disconnect();
     }
 }
 
 bool WorkerThreadableWebSocketChannel::Bridge::connect(const KURL& url, const String& protocol)
 {
     if (hasTerminatedPeer())
         return false;
 
     RefPtrWillBeRawPtr<Bridge> protect(this);
-    if (!waitForMethodCompletion(CallClosureTask::create(bind(&Peer::connect, m_peer, url.copy(), protocol.isolatedCopy()))))
+    // It is important to seprate task creation from calling
+    // waitForMethodCompletion. See the above comment.
+    OwnPtr<ExecutionContextTask> task = CallClosureTask::create(bind(&Peer::connect, m_peer, url.copy(), protocol.isolatedCopy()));
+    if (!waitForMethodCompletion(task.release()))
         return false;
 
     return m_syncHelper->connectRequestResult();
 }
 
 WebSocketChannel::SendResult WorkerThreadableWebSocketChannel::Bridge::send(const String& message)
 {
     if (hasTerminatedPeer())
         return WebSocketChannel::SendFail;
 
     RefPtrWillBeRawPtr<Bridge> protect(this);
-    if (!waitForMethodCompletion(CallClosureTask::create(bind(&Peer::send, m_peer, message.isolatedCopy()))))
+    // It is important to seprate task creation from calling
+    // waitForMethodCompletion. See the above comment.
+    OwnPtr<ExecutionContextTask> task = CallClosureTask::create(bind(&Peer::send, m_peer, message.isolatedCopy()));
+    if (!waitForMethodCompletion(task.release()))
         return WebSocketChannel::SendFail;
 
     return m_syncHelper->sendRequestResult();
 }
 
 WebSocketChannel::SendResult WorkerThreadableWebSocketChannel::Bridge::send(const ArrayBuffer& binaryData, unsigned byteOffset, unsigned byteLength)
 {
     if (hasTerminatedPeer())
         return WebSocketChannel::SendFail;
 
     // ArrayBuffer isn't thread-safe, hence the content of ArrayBuffer is copied into Vector<char>.
     OwnPtr<Vector<char> > data = adoptPtr(new Vector<char>(byteLength));
     if (binaryData.byteLength())
         memcpy(data->data(), static_cast<const char*>(binaryData.data()) + byteOffset, byteLength);
 
     RefPtrWillBeRawPtr<Bridge> protect(this);
-    if (!waitForMethodCompletion(CallClosureTask::create(bind(&Peer::sendArrayBuffer, m_peer, data.release()))))
+    // It is important to seprate task creation from calling
+    // waitForMethodCompletion. See the above comment.
+    OwnPtr<ExecutionContextTask> task = CallClosureTask::create(bind(&Peer::sendArrayBuffer, m_peer, data.release()));
+    if (!waitForMethodCompletion(task.release()))
         return WebSocketChannel::SendFail;
 
     return m_syncHelper->sendRequestResult();
 }
 
 WebSocketChannel::SendResult WorkerThreadableWebSocketChannel::Bridge::send(PassRefPtr<BlobDataHandle> data)
 {
     if (hasTerminatedPeer())
         return WebSocketChannel::SendFail;
 
     RefPtrWillBeRawPtr<Bridge> protect(this);
-    if (!waitForMethodCompletion(CallClosureTask::create(bind(&Peer::sendBlob, m_peer, data))))
+    // It is important to seprate task creation from calling
+    // waitForMethodCompletion. See the above comment.
+    OwnPtr<ExecutionContextTask> task = CallClosureTask::create(bind(&Peer::sendBlob, m_peer, data));
+    if (!waitForMethodCompletion(task.release()))
         return WebSocketChannel::SendFail;
 
     return m_syncHelper->sendRequestResult();
 }
 
 void WorkerThreadableWebSocketChannel::Bridge::close(int code, const String& reason)
 {
     if (hasTerminatedPeer())
         return;
 
-    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::close, m_peer, code, reason.isolatedCopy())));
+    // It is important to seprate task creation from calling
+    // waitForMethodCompletion. See the above comment.
+    OwnPtr<ExecutionContextTask> task = CallClosureTask::create(bind(&Peer::close, m_peer, code, reason.isolatedCopy()));
+    m_loaderProxy.postTaskToLoader(task.release());
 }
 
 void WorkerThreadableWebSocketChannel::Bridge::fail(const String& reason, MessageLevel level, const String& sourceURL, unsigned lineNumber)
 {
     if (hasTerminatedPeer())
         return;
 
-    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::fail, m_peer, reason.isolatedCopy(), level, sourceURL.isolatedCopy(), lineNumber)));
+    // It is important to seprate task creation from calling
+    // waitForMethodCompletion. See the above comment.
+    OwnPtr<ExecutionContextTask> task = CallClosureTask::create(bind(&Peer::fail, m_peer, reason.isolatedCopy(), level, sourceURL.isolatedCopy(), lineNumber));
+    m_loaderProxy.postTaskToLoader(task.release());
 }
 
 void WorkerThreadableWebSocketChannel::Bridge::disconnect()
 {
     if (hasTerminatedPeer())
         return;
 
     clearClientWrapper();
     terminatePeer();
 }
@@ skipping 18 matching lines @@
     events.append(m_syncHelper->event());
     ThreadState::SafePointScope scope(ThreadState::HeapPointersOnStack);
     blink::Platform::current()->waitMultipleEvents(events);
     // This is checking whether a shutdown event is fired or not.
     return !m_workerGlobalScope->thread()->runLoop().terminated();
 }
 
 void WorkerThreadableWebSocketChannel::Bridge::terminatePeer()
 {
     ASSERT(!hasTerminatedPeer());
+
+    // It is important to seprate task creation from calling
+    // waitForMethodCompletion. See the above comment.
+    OwnPtr<ExecutionContextTask> task = CallClosureTask::create(bind(&Peer::destroy, m_peer));
 #if ENABLE(OILPAN)
     // The worker thread has to wait for the main thread to complete Peer::destroy,
     // because the worker thread has to make sure that the main thread does not have any
     // references to on-heap objects allocated in the thread heap of the worker thread
     // before the worker thread shuts down.
-    waitForMethodCompletion(CallClosureTask::create(bind(&Peer::destroy, m_peer)));
+    waitForMethodCompletion(task.release());
 #else
-    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::destroy, m_peer)));
+    m_loaderProxy.postTaskToLoader(task.release());
 #endif
 
     // Peer::destroy() deletes m_peer and then m_syncHelper will be released.
     // We must not touch m_syncHelper any more.
     m_syncHelper = nullptr;
 
     // We won't use this any more.
     m_workerGlobalScope = nullptr;
 }
 
 void WorkerThreadableWebSocketChannel::Bridge::trace(Visitor* visitor)
 {
     visitor->trace(m_workerClientWrapper);
     visitor->trace(m_workerGlobalScope);
     visitor->trace(m_syncHelper);
     visitor->trace(m_peer);
 }
 
 } // namespace WebCore