Source/core/animation/TimedItem.h

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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 *
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 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
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 * 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
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 */

#ifndef TimedItem_h
#define TimedItem_h

#include "core/animation/Timing.h"
#include "wtf/OwnPtr.h"
#include "wtf/PassOwnPtr.h"
#include "wtf/RefCounted.h"

namespace WebCore {

class Player;
class TimedItem;

static inline bool isNull(double value)
{
    return std::isnan(value);
}

static inline double nullValue()
{
    return std::numeric_limits<double>::quiet_NaN();
}

class TimedItem : public RefCounted<TimedItem> {
    friend class Player; // Calls attach/detach, updateInheritedTime.
public:
    // Note that logic in CSSAnimations depends on the order of these values.
    enum Phase {
        PhaseBefore,
        PhaseActive,
        PhaseAfter,
        PhaseNone,
    };

    class EventDelegate {
    public:
        virtual ~EventDelegate() { };
        virtual void onEventCondition(const TimedItem*, bool isFirstSample, Phase previousPhase, double previousIteration) = 0;
    };

    virtual ~TimedItem() { }

    Phase phase() const { return ensureCalculated().phase; }
    bool isCurrent() const { return ensureCalculated().isCurrent; }
    bool isInEffect() const { return ensureCalculated().isInEffect; }
    bool isInPlay() const { return ensureCalculated().isInPlay; }
    double timeToEffectChange() const { return ensureCalculated().timeToEffectChange; }

    double startTime() const { return m_startTime; }

    double currentIteration() const { return ensureCalculated().currentIteration; }
    double activeDuration() const { return ensureCalculated().activeDuration; }
    double timeFraction() const { return ensureCalculated().timeFraction; }
    const Player* player() const { return m_player; }
    Player* player() { return m_player; }

    const Timing& specified() const { return m_specified; }

protected:
    TimedItem(const Timing&, PassOwnPtr<EventDelegate> = nullptr);

    // When TimedItem receives a new inherited time via updateInheritedTime
    // it will (if necessary) recalculate timings and (if necessary) call
    // updateChildrenAndEffects.
    void updateInheritedTime(double inheritedTime) const;

private:
    virtual void updateChildrenAndEffects() const = 0;
    virtual double intrinsicIterationDuration() const { return 0; };
    virtual void willDetach() = 0;
    virtual double calculateTimeToEffectChange(double inheritedTime, double activeTime, Phase) const = 0;

    void attach(Player* player) { m_player = player; };
    void detach()
    {
        ASSERT(m_player);
        willDetach();
        m_player = 0;
    };

    // FIXME: m_parent and m_startTime are placeholders, they depend on timing groups.
    TimedItem* const m_parent;
    const double m_startTime;
    Player* m_player;
    Timing m_specified;
    OwnPtr<EventDelegate> m_eventDelegate;

    // FIXME: Should be versioned by monotonic value on player.
    mutable struct CalculatedTiming {
        double activeDuration;
        Phase phase;
        double currentIteration;
        double timeFraction;
        bool isCurrent;
        bool isInEffect;
        bool isInPlay;
        double timeToEffectChange;
    } m_calculated;
    mutable bool m_isFirstSample;

    // FIXME: Should check the version and reinherit time if inconsistent.
    const CalculatedTiming& ensureCalculated() const { return m_calculated; }
};

} // namespace WebCore

#endif