/* * Copyright (C) 2010 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 * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef WorkerFileWriterCallbacksBridge_h #define WorkerFileWriterCallbacksBridge_h #if ENABLE(FILE_SYSTEM) && ENABLE(WORKERS) #include "KURL.h" #include "WebFileError.h" #include "WebFileWriterClient.h" #include "WorkerContext.h" #include <wtf/PassOwnPtr.h> #include <wtf/PassRefPtr.h> #include <wtf/ThreadSafeRefCounted.h> namespace WebCore { class AsyncFileWriterClient; class KURL; class WorkerLoaderProxy; } namespace WTF { class String; } using WTF::String; namespace WebKit { class WebFileSystem; class WebFileWriter; class WebFileWriterClient; class WebURL; class WebWorkerBase; // This class is used as a mechanism to bridge calls between threads. // Calls to a WebFileWriter must happen on the main thread, but they come from // the context thread. The responses through the WebFileWriterClient interface // start on the main thread, but must be sent via the worker context thread. // // A typical flow for write would look like this: // Bridge::postWriteToMainThread() on WorkerThread // --> Bridge::writeOnMainThread() is called on MainThread // --> WebFileWriter::write() // This makes an IPC; the actual operation is down in the browser. // --> Bridge::didWrite is called on MainThread // --> Bridge::didWriteOnWorkerThread is called on WorkerThread // This calls the original client (m_clientOnWorkerThread). // // The bridge object is refcounted, so that it doesn't get deleted while there // are cross-thread calls in flight. Each CrossThreadTask carries a reference // to the bridge, which guarantees that the bridge will still be valid when the // task is executed. In order to shut down the bridge, the WebFileWriterClient // should call postShutdownToMainThread before dropping its reference to the // bridge. This ensures that the WebFileWriter will be cleared on the main // thread and that no further calls to the WebFileWriterClient will be made. class WorkerFileWriterCallbacksBridge : public ThreadSafeRefCounted<WorkerFileWriterCallbacksBridge>, public WebCore::WorkerContext::Observer, public WebFileWriterClient { public: ~WorkerFileWriterCallbacksBridge(); // WorkerContext::Observer method. virtual void notifyStop(); static PassRefPtr<WorkerFileWriterCallbacksBridge> create(const WebCore::KURL& path, WebCore::WorkerLoaderProxy* proxy, WebCore::ScriptExecutionContext* workerContext, WebCore::AsyncFileWriterClient* client) { return adoptRef(new WorkerFileWriterCallbacksBridge(path, proxy, workerContext, client)); } // Methods that create an instance and post an initial request task to the main thread. They must be called on the worker thread. void postWriteToMainThread(long long position, const WebCore::KURL& data); void postTruncateToMainThread(long long length); void postAbortToMainThread(); // The owning WorkerAsyncFileWriterChromium should call this method before dropping its last reference to the bridge, on the context thread. // The actual deletion of the WorkerFileWriterCallbacksBridge may happen on either the main or context thread, depending on where the last reference goes away; that's safe as long as this is called first. void postShutdownToMainThread(PassRefPtr<WorkerFileWriterCallbacksBridge>); // Callback methods that are called on the main thread. // These are the implementation of WebKit::WebFileWriterClient. void didWrite(long long bytes, bool complete); void didFail(WebFileError); void didTruncate(); // Call this on the context thread to wait for the current operation to complete. bool waitForOperationToComplete(); private: WorkerFileWriterCallbacksBridge(const WebCore::KURL& path, WebCore::WorkerLoaderProxy*, WebCore::ScriptExecutionContext*, WebCore::AsyncFileWriterClient*); void postInitToMainThread(const WebCore::KURL& path); // Methods that are to be called on the main thread. static void writeOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, long long position, const WebCore::KURL& data); static void truncateOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, long long length); static void abortOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>); static void initOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, const WebCore::KURL& path); static void shutdownOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>); // Methods that dispatch to AsyncFileWriterClient on the worker threads. static void didWriteOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, long long length, bool complete); static void didFailOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, WebFileError); static void didTruncateOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>); // Called on the main thread to run the supplied task. static void runTaskOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, PassOwnPtr<WebCore::ScriptExecutionContext::Task>); // Called on the worker thread to run the supplied task. static void runTaskOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, PassOwnPtr<WebCore::ScriptExecutionContext::Task>); // Called on the worker thread to dispatch to the main thread. void dispatchTaskToMainThread(PassOwnPtr<WebCore::ScriptExecutionContext::Task>); // Called on the main thread to dispatch to the worker thread. void dispatchTaskToWorkerThread(PassOwnPtr<WebCore::ScriptExecutionContext::Task>); // Used from the main thread to post tasks to the context thread. WebCore::WorkerLoaderProxy* m_proxy; // Used on the context thread, only to check that we're running on the context thread. WebCore::ScriptExecutionContext* m_workerContext; // Created and destroyed from the main thread. OwnPtr<WebKit::WebFileWriter> m_writer; // Used on the context thread to call back into the client. WebCore::AsyncFileWriterClient* m_clientOnWorkerThread; // Used to indicate that shutdown has started on the main thread, and hence the writer has been deleted. bool m_writerDeleted; // Used by waitForOperationToComplete. bool m_operationInProgress; // Used by postTaskForModeToWorkerContext and runInMode. String m_mode; }; } // namespace WebCore #endif #endif // WorkerFileWriterCallbacksBridge_h