/*

 * Copyright (C) 2009 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,

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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef WorkerThreadableLoader_h

#define WorkerThreadableLoader_h

#if ENABLE(WORKERS)

#include "PlatformString.h"

#include "ThreadableLoader.h"

#include "ThreadableLoaderClient.h"

#include "ThreadableLoaderClientWrapper.h"

#include <memory>

#include <wtf/PassRefPtr.h>

#include <wtf/RefCounted.h>

#include <wtf/RefPtr.h>

#include <wtf/Threading.h>

namespace WebCore {

    class ResourceError;

    struct ResourceRequest;

    class WorkerContext;

    class WorkerLoaderProxy;

    struct CrossThreadResourceResponseData;

    struct CrossThreadResourceRequestData;

    class WorkerThreadableLoader : public RefCounted<WorkerThreadableLoader>, public ThreadableLoader {

    public:

        static void loadResourceSynchronously(WorkerContext*, const ResourceRequest&, ThreadableLoaderClient&, const ThreadableLoaderOptions&);

        static PassRefPtr<WorkerThreadableLoader> create(WorkerContext* workerContext, ThreadableLoaderClient* client, const String& taskMode, const ResourceRequest& request, const ThreadableLoaderOptions& options)

        {

            return adoptRef(new WorkerThreadableLoader(workerContext, client, taskMode, request, options));

        }

        ~WorkerThreadableLoader();

        virtual void cancel();

        bool done() const { return m_workerClientWrapper->done(); }

        using RefCounted<WorkerThreadableLoader>::ref;

        using RefCounted<WorkerThreadableLoader>::deref;

    protected:

        virtual void refThreadableLoader() { ref(); }

        virtual void derefThreadableLoader() { deref(); }

    private:

        // Creates a loader on the main thread and bridges communication between

        // the main thread and the worker context's thread where WorkerThreadableLoader runs.

        //

        // Regarding the bridge and lifetimes of items used in callbacks, there are a few cases:

        //

        // all cases. All tasks posted from the worker context's thread are ok because

        //    the last task posted always is "mainThreadDestroy", so MainThreadBridge is

        //    around for all tasks that use it on the mian thread.

        //

        // case 1. worker.terminate is called.

        //    In this case, no more tasks are posted from the worker object's thread to the worker

        //    context's thread -- WorkerContextProxy implementation enforces this.

        //

        // case 2. xhr gets aborted and the worker context continues running.

        //    The ThreadableLoaderClientWrapper has the underlying client cleared, so no more calls

        //    go through it.  All tasks posted from the worker object's thread to the worker context's

        //    thread do "ThreadableLoaderClientWrapper::ref" (automatically inside of the cross thread copy

        //    done in createCallbackTask), so the ThreadableLoaderClientWrapper instance is there until all

        //    tasks are executed.

        class MainThreadBridge : ThreadableLoaderClient {

        public:

            // All executed on the worker context's thread.

            MainThreadBridge(PassRefPtr<ThreadableLoaderClientWrapper>, WorkerLoaderProxy&, const String& taskMode, const ResourceRequest&, const ThreadableLoaderOptions&);

            void cancel();

            void destroy();

        private:

            // Executed on the worker context's thread.

            void clearClientWrapper();

            // All executed on the main thread.

            static void mainThreadDestroy(ScriptExecutionContext*, MainThreadBridge*);

            ~MainThreadBridge();

            static void mainThreadCreateLoader(ScriptExecutionContext*, MainThreadBridge*, std::auto_ptr<CrossThreadResourceRequestData>, ThreadableLoaderOptions);

            static void mainThreadCancel(ScriptExecutionContext*, MainThreadBridge*);

            virtual void didSendData(unsigned long long bytesSent, unsigned long long totalBytesToBeSent);

            virtual void didReceiveResponse(const ResourceResponse&);

            virtual void didReceiveData(const char*, int lengthReceived);

            virtual void didFinishLoading(unsigned long identifier);

            virtual void didFail(const ResourceError&);

            virtual void didFailRedirectCheck();

            virtual void didReceiveAuthenticationCancellation(const ResourceResponse&);

            // Only to be used on the main thread.

            RefPtr<ThreadableLoader> m_mainThreadLoader;

            // ThreadableLoaderClientWrapper is to be used on the worker context thread.

            // The ref counting is done on either thread.

            RefPtr<ThreadSafeShared<ThreadableLoaderClientWrapper> > m_workerClientWrapper;

            // May be used on either thread.

            WorkerLoaderProxy& m_loaderProxy;

            // For use on the main thread.

            String m_taskMode;

        };

        WorkerThreadableLoader(WorkerContext*, ThreadableLoaderClient*, const String& taskMode, const ResourceRequest&, const ThreadableLoaderOptions&);

        RefPtr<WorkerContext> m_workerContext;

        RefPtr<ThreadableLoaderClientWrapper> m_workerClientWrapper;

        MainThreadBridge& m_bridge;

    };

} // namespace WebCore

#endif // ENABLE(WORKERS)

#endif // WorkerThreadableLoader_h