Cleanup WorkerThreadableWebSocketChannel's logic to wait for the main thread

Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp

Index: Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp
diff --git a/Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp b/Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp
index ccd5fcc111119a4a7322c0c6885f300cd99a2fe7..cd6c3213939c1ad5150fcd0233eef16b9e2bec8a 100644
--- a/Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp
+++ b/Source/modules/websockets/WorkerThreadableWebSocketChannel.cpp
@@ -120,10 +120,9 @@ private:
     unsigned long m_bufferedAmount;
 };
 
-WorkerThreadableWebSocketChannel::WorkerThreadableWebSocketChannel(WorkerGlobalScope& context, WebSocketChannelClient* client, const String& sourceURL, unsigned lineNumber)
-    : m_workerGlobalScope(context)
-    , m_workerClientWrapper(ThreadableWebSocketChannelClientWrapper::create(client))
-    , m_bridge(Bridge::create(m_workerClientWrapper, m_workerGlobalScope))
+WorkerThreadableWebSocketChannel::WorkerThreadableWebSocketChannel(WorkerGlobalScope& workerGlobalScope, WebSocketChannelClient* client, const String& sourceURL, unsigned lineNumber)
+    : m_workerClientWrapper(ThreadableWebSocketChannelClientWrapper::create(client))
+    , m_bridge(Bridge::create(m_workerClientWrapper, workerGlobalScope))
     , m_sourceURLAtConnection(sourceURL)
     , m_lineNumberAtConnection(lineNumber)
 {
@@ -457,7 +456,7 @@ void WorkerThreadableWebSocketChannel::Peer::didReceiveMessageError()
     m_loaderProxy.postTaskToWorkerGlobalScope(createCallbackTask(&workerGlobalScopeDidReceiveMessageError, m_workerClientWrapper));
 }
 
-WorkerThreadableWebSocketChannel::Bridge::Bridge(PassRefPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper, PassRefPtrWillBeRawPtr<WorkerGlobalScope> workerGlobalScope)
+WorkerThreadableWebSocketChannel::Bridge::Bridge(PassRefPtr<ThreadableWebSocketChannelClientWrapper> workerClientWrapper, WorkerGlobalScope& workerGlobalScope)
     : m_workerClientWrapper(workerClientWrapper)
     , m_workerGlobalScope(workerGlobalScope)
     , m_loaderProxy(m_workerGlobalScope->thread()->workerLoaderProxy())
@@ -490,71 +489,87 @@ void WorkerThreadableWebSocketChannel::Bridge::initialize(const String& sourceUR
 
 bool WorkerThreadableWebSocketChannel::Bridge::connect(const KURL& url, const String& protocol)
 {
-    if (!m_workerGlobalScope)
+    if (hasTerminatedPeer())
         return false;
-    ASSERT(m_syncHelper);
-    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::connect, m_peer, url.copy(), protocol.isolatedCopy())));
+
     RefPtr<Bridge> protect(this);

[yhirano, 2014/05/07 08:05:18]

Can you tell me why this move is needed? I think posting a task can't delete
|this|.

[tyoshino (SeeGerritForStatus), 2014/05/08 05:03:00]

As discussed offline, it looks we no longer need these protects. But for this
CL, let's keep them and just let me make their position consistent.

-    waitForMethodCompletion();
+    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::connect, m_peer, url.copy(), protocol.isolatedCopy())));
+    if (!waitForMethodCompletion())

[yhirano, 2014/05/07 08:05:18]

[optional] We could have postTaskAndWait for this pattern.

[tyoshino (SeeGerritForStatus), 2014/05/08 05:03:00]

Done.

+        return false;
+
     return m_syncHelper->connectRequestResult();
 }
 
 WebSocketChannel::SendResult WorkerThreadableWebSocketChannel::Bridge::send(const String& message)
 {
-    if (!m_workerGlobalScope)
+    if (hasTerminatedPeer())
         return WebSocketChannel::SendFail;
-    ASSERT(m_syncHelper);
-    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::send, m_peer, message.isolatedCopy())));
+
     RefPtr<Bridge> protect(this);
-    waitForMethodCompletion();
+    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::send, m_peer, message.isolatedCopy())));
+    if (!waitForMethodCompletion())
+        return WebSocketChannel::SendFail;
+
     return m_syncHelper->sendRequestResult();
 }
 
 WebSocketChannel::SendResult WorkerThreadableWebSocketChannel::Bridge::send(const ArrayBuffer& binaryData, unsigned byteOffset, unsigned byteLength)
 {
-    if (!m_workerGlobalScope)
+    if (hasTerminatedPeer())
         return WebSocketChannel::SendFail;
-    ASSERT(m_syncHelper);
+
     // 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);
 
-    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::sendArrayBuffer, m_peer, data.release())));
     RefPtr<Bridge> protect(this);
-    waitForMethodCompletion();
+    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::sendArrayBuffer, m_peer, data.release())));
+    if (!waitForMethodCompletion())
+        return WebSocketChannel::SendFail;
+
     return m_syncHelper->sendRequestResult();
 }
 
 WebSocketChannel::SendResult WorkerThreadableWebSocketChannel::Bridge::send(PassRefPtr<BlobDataHandle> data)
 {
-    if (!m_workerGlobalScope)
+    if (hasTerminatedPeer())
         return WebSocketChannel::SendFail;
-    ASSERT(m_syncHelper);
-    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::sendBlob, m_peer, data)));
+
     RefPtr<Bridge> protect(this);
-    waitForMethodCompletion();
+    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::sendBlob, m_peer, data)));
+    if (!waitForMethodCompletion())
+        return WebSocketChannel::SendFail;
+
     return m_syncHelper->sendRequestResult();
 }
 
 unsigned long WorkerThreadableWebSocketChannel::Bridge::bufferedAmount()
 {
-    if (!m_workerGlobalScope)
+    if (hasTerminatedPeer())
         return 0;
-    ASSERT(m_syncHelper);
-    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::bufferedAmount, m_peer)));
+
     RefPtr<Bridge> protect(this);
-    waitForMethodCompletion();
+    m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::bufferedAmount, m_peer)));
+    if (!waitForMethodCompletion())
+        return 0;
+
     return m_syncHelper->bufferedAmount();
 }
 
 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())));
 }
 
 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)));
 }
 
@@ -566,11 +581,17 @@ void WorkerThreadableWebSocketChannel::Bridge::disconnect()
 
 void WorkerThreadableWebSocketChannel::Bridge::suspend()
 {
+    if (hasTerminatedPeer())
+        return;
+
     m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::suspend, m_peer)));
 }
 
 void WorkerThreadableWebSocketChannel::Bridge::resume()
 {
+    if (hasTerminatedPeer())
+        return;
+
     m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::resume, m_peer)));
 }
 
@@ -583,8 +604,8 @@ void WorkerThreadableWebSocketChannel::Bridge::clearClientWrapper()
 // which causes the bridge to get disconnected from the WebSocket and deleted if there is no other reference.
 bool WorkerThreadableWebSocketChannel::Bridge::waitForMethodCompletion()
 {
-    if (!m_syncHelper)
-        return true;
+    ASSERT(m_workerGlobalScope);
+    ASSERT(m_syncHelper);
 
     blink::WebWaitableEvent* shutdownEvent = m_workerGlobalScope->thread()->shutdownEvent();
     Vector<blink::WebWaitableEvent*> events;
@@ -599,8 +620,12 @@ bool WorkerThreadableWebSocketChannel::Bridge::waitForMethodCompletion()
 void WorkerThreadableWebSocketChannel::Bridge::terminatePeer()
 {
     m_loaderProxy.postTaskToLoader(CallClosureTask::create(bind(&Peer::destroy, m_peer)));
-    m_workerGlobalScope = nullptr;
+    // Peer::destroy() deletes m_peer and then m_syncHelper will be released.
+    // We must not touch m_syncHelper any more.
     m_syncHelper = 0;
+
+    // We won't use this any more.
+    m_workerGlobalScope = nullptr;
 }
 
 } // namespace WebCore