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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 <wtf/PassOwnPtr.h>
     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         WTF_MAKE_FAST_ALLOCATED;
     58     public:
     59         static void loadResourceSynchronously(WorkerContext*, const ResourceRequest&, ThreadableLoaderClient&, const ThreadableLoaderOptions&);
     60         static PassRefPtr<WorkerThreadableLoader> create(WorkerContext* workerContext, ThreadableLoaderClient* client, const String& taskMode, const ResourceRequest& request, const ThreadableLoaderOptions& options)
     61         {
     62             return adoptRef(new WorkerThreadableLoader(workerContext, client, taskMode, request, options));
     63         }
     64 
     65         ~WorkerThreadableLoader();
     66 
     67         virtual void cancel();
     68 
     69         bool done() const { return m_workerClientWrapper->done(); }
     70 
     71         using RefCounted<WorkerThreadableLoader>::ref;
     72         using RefCounted<WorkerThreadableLoader>::deref;
     73 
     74     protected:
     75         virtual void refThreadableLoader() { ref(); }
     76         virtual void derefThreadableLoader() { deref(); }
     77 
     78     private:
     79         // Creates a loader on the main thread and bridges communication between
     80         // the main thread and the worker context's thread where WorkerThreadableLoader runs.
     81         //
     82         // Regarding the bridge and lifetimes of items used in callbacks, there are a few cases:
     83         //
     84         // all cases. All tasks posted from the worker context's thread are ok because
     85         //    the last task posted always is "mainThreadDestroy", so MainThreadBridge is
     86         //    around for all tasks that use it on the main thread.
     87         //
     88         // case 1. worker.terminate is called.
     89         //    In this case, no more tasks are posted from the worker object's thread to the worker
     90         //    context's thread -- WorkerContextProxy implementation enforces this.
     91         //
     92         // case 2. xhr gets aborted and the worker context continues running.
     93         //    The ThreadableLoaderClientWrapper has the underlying client cleared, so no more calls
     94         //    go through it.  All tasks posted from the worker object's thread to the worker context's
     95         //    thread do "ThreadableLoaderClientWrapper::ref" (automatically inside of the cross thread copy
     96         //    done in createCallbackTask), so the ThreadableLoaderClientWrapper instance is there until all
     97         //    tasks are executed.
     98         class MainThreadBridge : public ThreadableLoaderClient {
     99         public:
    100             // All executed on the worker context's thread.
    101             MainThreadBridge(PassRefPtr<ThreadableLoaderClientWrapper>, WorkerLoaderProxy&, const String& taskMode, const ResourceRequest&, const ThreadableLoaderOptions&, const String& outgoingReferrer);
    102             void cancel();
    103             void destroy();
    104 
    105         private:
    106             // Executed on the worker context's thread.
    107             void clearClientWrapper();
    108 
    109             // All executed on the main thread.
    110             static void mainThreadDestroy(ScriptExecutionContext*, MainThreadBridge*);
    111             ~MainThreadBridge();
    112 
    113             static void mainThreadCreateLoader(ScriptExecutionContext*, MainThreadBridge*, PassOwnPtr<CrossThreadResourceRequestData>, ThreadableLoaderOptions, const String& outgoingReferrer);
    114             static void mainThreadCancel(ScriptExecutionContext*, MainThreadBridge*);
    115             virtual void didSendData(unsigned long long bytesSent, unsigned long long totalBytesToBeSent);
    116             virtual void didReceiveResponse(const ResourceResponse&);
    117             virtual void didReceiveData(const char*, int dataLength);
    118             virtual void didReceiveCachedMetadata(const char*, int dataLength);
    119             virtual void didFinishLoading(unsigned long identifier, double finishTime);
    120             virtual void didFail(const ResourceError&);
    121             virtual void didFailRedirectCheck();
    122             virtual void didReceiveAuthenticationCancellation(const ResourceResponse&);
    123 
    124             // Only to be used on the main thread.
    125             RefPtr<ThreadableLoader> m_mainThreadLoader;
    126 
    127             // ThreadableLoaderClientWrapper is to be used on the worker context thread.
    128             // The ref counting is done on either thread.
    129             RefPtr<ThreadableLoaderClientWrapper> m_workerClientWrapper;
    130 
    131             // May be used on either thread.
    132             WorkerLoaderProxy& m_loaderProxy;
    133 
    134             // For use on the main thread.
    135             String m_taskMode;
    136         };
    137 
    138         WorkerThreadableLoader(WorkerContext*, ThreadableLoaderClient*, const String& taskMode, const ResourceRequest&, const ThreadableLoaderOptions&);
    139 
    140         RefPtr<WorkerContext> m_workerContext;
    141         RefPtr<ThreadableLoaderClientWrapper> m_workerClientWrapper;
    142         MainThreadBridge& m_bridge;
    143     };
    144 
    145 } // namespace WebCore
    146 
    147 #endif // ENABLE(WORKERS)
    148 
    149 #endif // WorkerThreadableLoader_h
    150