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      1 /*
      2  * Copyright (C) 2009 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 WorkerThreadableLoader_h
     32 #define WorkerThreadableLoader_h
     33 
     34 #if ENABLE(WORKERS)
     35 
     36 #include "PlatformString.h"
     37 #include "ThreadableLoader.h"
     38 #include "ThreadableLoaderClient.h"
     39 #include "ThreadableLoaderClientWrapper.h"
     40 
     41 #include <memory>
     42 #include <wtf/PassRefPtr.h>
     43 #include <wtf/RefCounted.h>
     44 #include <wtf/RefPtr.h>
     45 #include <wtf/Threading.h>
     46 
     47 namespace WebCore {
     48 
     49     class ResourceError;
     50     class ResourceRequest;
     51     class WorkerContext;
     52     class WorkerLoaderProxy;
     53     struct CrossThreadResourceResponseData;
     54     struct CrossThreadResourceRequestData;
     55 
     56     class WorkerThreadableLoader : public RefCounted<WorkerThreadableLoader>, public ThreadableLoader {
     57     public:
     58         static void loadResourceSynchronously(WorkerContext*, const ResourceRequest&, ThreadableLoaderClient&, const ThreadableLoaderOptions&);
     59         static PassRefPtr<WorkerThreadableLoader> create(WorkerContext* workerContext, ThreadableLoaderClient* client, const String& taskMode, const ResourceRequest& request, const ThreadableLoaderOptions& options)
     60         {
     61             return adoptRef(new WorkerThreadableLoader(workerContext, client, taskMode, request, options));
     62         }
     63 
     64         ~WorkerThreadableLoader();
     65 
     66         virtual void cancel();
     67 
     68         bool done() const { return m_workerClientWrapper->done(); }
     69 
     70         using RefCounted<WorkerThreadableLoader>::ref;
     71         using RefCounted<WorkerThreadableLoader>::deref;
     72 
     73     protected:
     74         virtual void refThreadableLoader() { ref(); }
     75         virtual void derefThreadableLoader() { deref(); }
     76 
     77     private:
     78         // Creates a loader on the main thread and bridges communication between
     79         // the main thread and the worker context's thread where WorkerThreadableLoader runs.
     80         //
     81         // Regarding the bridge and lifetimes of items used in callbacks, there are a few cases:
     82         //
     83         // all cases. All tasks posted from the worker context's thread are ok because
     84         //    the last task posted always is "mainThreadDestroy", so MainThreadBridge is
     85         //    around for all tasks that use it on the main thread.
     86         //
     87         // case 1. worker.terminate is called.
     88         //    In this case, no more tasks are posted from the worker object's thread to the worker
     89         //    context's thread -- WorkerContextProxy implementation enforces this.
     90         //
     91         // case 2. xhr gets aborted and the worker context continues running.
     92         //    The ThreadableLoaderClientWrapper has the underlying client cleared, so no more calls
     93         //    go through it.  All tasks posted from the worker object's thread to the worker context's
     94         //    thread do "ThreadableLoaderClientWrapper::ref" (automatically inside of the cross thread copy
     95         //    done in createCallbackTask), so the ThreadableLoaderClientWrapper instance is there until all
     96         //    tasks are executed.
     97         class MainThreadBridge : public ThreadableLoaderClient {
     98         public:
     99             // All executed on the worker context's thread.
    100             MainThreadBridge(PassRefPtr<ThreadableLoaderClientWrapper>, WorkerLoaderProxy&, const String& taskMode, const ResourceRequest&, const ThreadableLoaderOptions&);
    101             void cancel();
    102             void destroy();
    103 
    104         private:
    105             // Executed on the worker context's thread.
    106             void clearClientWrapper();
    107 
    108             // All executed on the main thread.
    109             static void mainThreadDestroy(ScriptExecutionContext*, MainThreadBridge*);
    110             ~MainThreadBridge();
    111 
    112             static void mainThreadCreateLoader(ScriptExecutionContext*, MainThreadBridge*, std::auto_ptr<CrossThreadResourceRequestData>, ThreadableLoaderOptions);
    113             static void mainThreadCancel(ScriptExecutionContext*, MainThreadBridge*);
    114             virtual void didSendData(unsigned long long bytesSent, unsigned long long totalBytesToBeSent);
    115             virtual void didReceiveResponse(const ResourceResponse&);
    116             virtual void didReceiveData(const char*, int lengthReceived);
    117             virtual void didFinishLoading(unsigned long identifier);
    118             virtual void didFail(const ResourceError&);
    119             virtual void didFailRedirectCheck();
    120             virtual void didReceiveAuthenticationCancellation(const ResourceResponse&);
    121 
    122             // Only to be used on the main thread.
    123             RefPtr<ThreadableLoader> m_mainThreadLoader;
    124 
    125             // ThreadableLoaderClientWrapper is to be used on the worker context thread.
    126             // The ref counting is done on either thread.
    127             RefPtr<ThreadableLoaderClientWrapper> m_workerClientWrapper;
    128 
    129             // May be used on either thread.
    130             WorkerLoaderProxy& m_loaderProxy;
    131 
    132             // For use on the main thread.
    133             String m_taskMode;
    134         };
    135 
    136         WorkerThreadableLoader(WorkerContext*, ThreadableLoaderClient*, const String& taskMode, const ResourceRequest&, const ThreadableLoaderOptions&);
    137 
    138         RefPtr<WorkerContext> m_workerContext;
    139         RefPtr<ThreadableLoaderClientWrapper> m_workerClientWrapper;
    140         MainThreadBridge& m_bridge;
    141     };
    142 
    143 } // namespace WebCore
    144 
    145 #endif // ENABLE(WORKERS)
    146 
    147 #endif // WorkerThreadableLoader_h
    148