/*
 * 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,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#if ENABLE(WORKERS)

#include "PlatformString.h"
#include "ThreadableLoader.h"
#include "ThreadableLoaderClient.h"
#include "ThreadableLoaderClientWrapper.h"

#include <wtf/PassOwnPtr.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefCounted.h>
#include <wtf/RefPtr.h>
#include <wtf/Threading.h>

namespace WebCore {

class ContentSecurityPolicy;
class DocumentThreadableLoader;
class ResourceError;
class ResourceRequest;
class WorkerGlobalScope;
class WorkerLoaderProxy;
struct CrossThreadResourceResponseData;
struct CrossThreadResourceRequestData;

class WorkerThreadableLoader : public RefCounted<WorkerThreadableLoader>, public ThreadableLoader {
	WTF_MAKE_FAST_ALLOCATED;
public:
	static void loadResourceSynchronously(WorkerGlobalScope*, ResourceRequest&, ThreadableLoaderClient&, const ThreadableLoaderOptions&);
	static PassRefPtr<WorkerThreadableLoader> create(WorkerGlobalScope* workerGlobalScope, ThreadableLoaderClient* client, const String& taskMode, ResourceRequest& request, const ThreadableLoaderOptions& options, const String& referrer)
	{
		return adoptRef(new WorkerThreadableLoader(workerGlobalScope, client, taskMode, request, options, referrer));
	}

	~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 main 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 -- WorkerGlobalScopeProxy 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 final : public ThreadableLoaderClient {
	public:
		// All executed on the worker context's thread.
		MainThreadBridge(PassRefPtr<ThreadableLoaderClientWrapper>, WorkerLoaderProxy&, const String& taskMode, const ResourceRequest&, const ThreadableLoaderOptions&, const String& outgoingReferrer, const SecurityOrigin*, const ContentSecurityPolicy*);
		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*, PassOwnPtr<CrossThreadResourceRequestData>, PassOwnPtr<ThreadableLoaderOptions>, PassRefPtr<SecurityOrigin>, PassOwnPtr<ContentSecurityPolicy>, const String& outgoingReferrer);
		static void mainThreadCancel(ScriptExecutionContext*, MainThreadBridge*);
		virtual void didSendData(unsigned long long bytesSent, unsigned long long totalBytesToBeSent) override;
		virtual void didReceiveResponse(unsigned long identifier, const ResourceResponse&) override;
		virtual void didReceiveData(const char*, int dataLength) override;
		virtual void didReceiveCachedMetadata(const char*, int dataLength) override;
		virtual void didFinishLoading(unsigned long identifier, double finishTime) override;
		virtual void didFail(const ResourceError&) override;

		// Only to be used on the main thread.
		RefPtr<DocumentThreadableLoader> m_mainThreadLoader;
		bool m_loadingFinished;

		// ThreadableLoaderClientWrapper is to be used on the worker context thread.
		// The ref counting is done on either thread.
		RefPtr<ThreadableLoaderClientWrapper> m_workerClientWrapper;

		// May be used on either thread.
		WorkerLoaderProxy& m_loaderProxy;

		// For use on the main thread.
		String m_taskMode;
	};

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

	RefPtr<ThreadableLoaderClientWrapper> m_workerClientWrapper;
	MainThreadBridge& m_bridge;
};

} // namespace WebCore

#endif // ENABLE(WORKERS)
