Source/WebCore/page/DOMTimer.h

/*
 * Copyright (C) 2008, 2014 Apple 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:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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.
 *
 */

#ifndef DOMTimer_h
#define DOMTimer_h

#include "SuspendableTimer.h"
#include <memory>
#include <wtf/RefCounted.h>

namespace WebCore {

    class DOMTimerFireState;
    class Document;
    class Element;
    class HTMLPlugInElement;
    class IntRect;
    class ScheduledAction;

    class DOMTimer final : public RefCounted<DOMTimer>, public SuspendableTimer {
        WTF_MAKE_NONCOPYABLE(DOMTimer);
        WTF_MAKE_FAST_ALLOCATED;
    public:
        virtual ~DOMTimer();

        static double defaultMinimumInterval() { return 0.004; } // 4 milliseconds.
        static double defaultAlignmentInterval() { return 0; }
        static double hiddenPageAlignmentInterval() { return 1.0; } // 1 second.

        // Creates a new timer owned by specified ScriptExecutionContext, starts it
        // and returns its Id.
        static int install(ScriptExecutionContext&, std::unique_ptr<ScheduledAction>, int timeout, bool singleShot);
        static void removeById(ScriptExecutionContext&, int timeoutId);

        // Notify that the interval may need updating (e.g. because the minimum interval
        // setting for the context has changed).
        void updateTimerIntervalIfNecessary();

        static void scriptDidInteractWithPlugin(HTMLPlugInElement&);

    private:
        DOMTimer(ScriptExecutionContext&, std::unique_ptr<ScheduledAction>, int interval, bool singleShot);
        friend class Internals;

        double intervalClampedToMinimum() const;

        bool isDOMTimersThrottlingEnabled(Document&) const;
        void updateThrottlingStateIfNecessary(const DOMTimerFireState&);

        // SuspendableTimer
        void fired() override;
        void didStop() override;
        double alignedFireTime(double) const override;

        // ActiveDOMObject API.
        const char* activeDOMObjectName() const override;

        enum TimerThrottleState {
            Undetermined,
            ShouldThrottle,
            ShouldNotThrottle
        };

        int m_timeoutId;
        int m_nestingLevel;
        std::unique_ptr<ScheduledAction> m_action;
        int m_originalInterval;
        TimerThrottleState m_throttleState;
        double m_currentTimerInterval;
        bool m_shouldForwardUserGesture;
    };

} // namespace WebCore

#endif // DOMTimer_h