1 /* 2 * Copyright (C) 2010 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #ifndef WorkerFileWriterCallbacksBridge_h 32 #define WorkerFileWriterCallbacksBridge_h 33 34 #include "WebFileWriterClient.h" 35 #include "core/workers/WorkerGlobalScope.h" 36 #include "public/platform/WebFileError.h" 37 #include "wtf/PassOwnPtr.h" 38 #include "wtf/PassRefPtr.h" 39 #include "wtf/ThreadSafeRefCounted.h" 40 41 namespace WebCore { 42 class AsyncFileWriterClient; 43 class KURL; 44 class WorkerLoaderProxy; 45 } 46 47 namespace WTF { 48 class String; 49 } 50 using WTF::String; 51 52 namespace WebKit { 53 54 class WebFileSystem; 55 class WebFileWriter; 56 class WebFileWriterClient; 57 class WebURL; 58 class WebWorkerBase; 59 60 // This class is used as a mechanism to bridge calls between threads. 61 // Calls to a WebFileWriter must happen on the main thread, but they come from 62 // the context thread. The responses through the WebFileWriterClient interface 63 // start on the main thread, but must be sent via the worker context thread. 64 // 65 // A typical flow for write would look like this: 66 // Bridge::postWriteToMainThread() on WorkerThread 67 // --> Bridge::writeOnMainThread() is called on MainThread 68 // --> WebFileWriter::write() 69 // This makes an IPC; the actual operation is down in the browser. 70 // --> Bridge::didWrite is called on MainThread 71 // --> Bridge::didWriteOnWorkerThread is called on WorkerThread 72 // This calls the original client (m_clientOnWorkerThread). 73 // 74 // The bridge object is refcounted, so that it doesn't get deleted while there 75 // are cross-thread calls in flight. Each CrossThreadTask carries a reference 76 // to the bridge, which guarantees that the bridge will still be valid when the 77 // task is executed. In order to shut down the bridge, the WebFileWriterClient 78 // should call postShutdownToMainThread before dropping its reference to the 79 // bridge. This ensures that the WebFileWriter will be cleared on the main 80 // thread and that no further calls to the WebFileWriterClient will be made. 81 class WorkerFileWriterCallbacksBridge : public ThreadSafeRefCounted<WorkerFileWriterCallbacksBridge>, public WebCore::WorkerGlobalScope::Observer, public WebFileWriterClient { 82 public: 83 ~WorkerFileWriterCallbacksBridge(); 84 85 // WorkerGlobalScope::Observer method. 86 virtual void notifyStop(); 87 88 static PassRefPtr<WorkerFileWriterCallbacksBridge> create(const WebCore::KURL& path, WebCore::WorkerLoaderProxy* proxy, WebCore::ScriptExecutionContext* workerGlobalScope, WebCore::AsyncFileWriterClient* client) 89 { 90 return adoptRef(new WorkerFileWriterCallbacksBridge(path, proxy, workerGlobalScope, client)); 91 } 92 93 // Methods that create an instance and post an initial request task to the main thread. They must be called on the worker thread. 94 void postWriteToMainThread(long long position, const WebCore::KURL& data); 95 void postTruncateToMainThread(long long length); 96 void postAbortToMainThread(); 97 98 // The owning WorkerAsyncFileWriterChromium should call this method before dropping its last reference to the bridge, on the context thread. 99 // 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. 100 void postShutdownToMainThread(PassRefPtr<WorkerFileWriterCallbacksBridge>); 101 102 // Callback methods that are called on the main thread. 103 // These are the implementation of WebKit::WebFileWriterClient. 104 void didWrite(long long bytes, bool complete); 105 void didFail(WebFileError); 106 void didTruncate(); 107 108 // Call this on the context thread to wait for the current operation to complete. 109 bool waitForOperationToComplete(); 110 111 private: 112 WorkerFileWriterCallbacksBridge(const WebCore::KURL& path, WebCore::WorkerLoaderProxy*, WebCore::ScriptExecutionContext*, WebCore::AsyncFileWriterClient*); 113 114 void postInitToMainThread(const WebCore::KURL& path); 115 116 // Methods that are to be called on the main thread. 117 static void writeOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, long long position, const WebCore::KURL& data); 118 static void truncateOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, long long length); 119 static void abortOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>); 120 static void initOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, const WebCore::KURL& path); 121 static void shutdownOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>); 122 123 // Methods that dispatch to AsyncFileWriterClient on the worker threads. 124 static void didWriteOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, long long length, bool complete); 125 static void didFailOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, WebFileError); 126 static void didTruncateOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>); 127 128 // Called on the main thread to run the supplied task. 129 static void runTaskOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, PassOwnPtr<WebCore::ScriptExecutionContext::Task>); 130 // Called on the worker thread to run the supplied task. 131 static void runTaskOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, PassOwnPtr<WebCore::ScriptExecutionContext::Task>); 132 133 // Called on the worker thread to dispatch to the main thread. 134 void dispatchTaskToMainThread(PassOwnPtr<WebCore::ScriptExecutionContext::Task>); 135 // Called on the main thread to dispatch to the worker thread. 136 void dispatchTaskToWorkerThread(PassOwnPtr<WebCore::ScriptExecutionContext::Task>); 137 138 // Used from the main thread to post tasks to the context thread. 139 WebCore::WorkerLoaderProxy* m_proxy; 140 141 // Mutex for proxy. 142 Mutex m_loaderProxyMutex; 143 144 // Used on the context thread, only to check that we're running on the context thread. 145 WebCore::ScriptExecutionContext* m_workerGlobalScope; 146 147 // Created and destroyed from the main thread. 148 OwnPtr<WebKit::WebFileWriter> m_writer; 149 150 // Used on the context thread to call back into the client. 151 WebCore::AsyncFileWriterClient* m_clientOnWorkerThread; 152 153 // Used to indicate that shutdown has started on the main thread, and hence the writer has been deleted. 154 bool m_writerDeleted; 155 156 // Used by waitForOperationToComplete. 157 bool m_operationInProgress; 158 159 // Used by postTaskForModeToWorkerGlobalScope and runInMode. 160 String m_mode; 161 }; 162 163 } // namespace WebCore 164 165 #endif // WorkerFileWriterCallbacksBridge_h 166
