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