/*
 * Copyright (C) 2014 Google Inc. All rights reserved.
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 * 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.
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 * 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
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 */

#ifndef MessageLoopInterruptor_h
#define MessageLoopInterruptor_h

#include "platform/heap/ThreadState.h"
#include "public/platform/WebThread.h"

namespace WebCore {

class MessageLoopInterruptor : public ThreadState::Interruptor {
public:
    explicit MessageLoopInterruptor(blink::WebThread* thread) : m_thread(thread) { }

    virtual void requestInterrupt() OVERRIDE
    {
        // GCTask has an empty run() method. Its only purpose is to guarantee
        // that MessageLoop will have a task to process which will result
        // in PendingGCRunner::didProcessTask being executed.
        m_thread->postTask(new GCTask);
    }

    virtual void clearInterrupt() OVERRIDE { }

private:
    class GCTask : public blink::WebThread::Task {
    public:
        virtual ~GCTask() { }

        virtual void run() OVERRIDE
        {
            // Don't do anything here because we don't know if this is
            // a nested event loop or not. PendingGCRunner::didProcessTask
            // will enter correct safepoint for us.
            // We are not calling onInterrupted() because that always
            // conservatively enters safepoint with pointers on stack.
        }
    };

    blink::WebThread* m_thread;
};

}

#endif
