Source/WebCore/animation/KeyframeEffectStack.cpp

/*
 * Copyright (C) 2019 Apple Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
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 *
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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#include "config.h"
#include "KeyframeEffectStack.h"

#include "CSSAnimation.h"
#include "CSSTransition.h"
#include "KeyframeEffect.h"
#include "WebAnimation.h"

namespace WebCore {

KeyframeEffectStack::KeyframeEffectStack()
{
}

KeyframeEffectStack::~KeyframeEffectStack()
{
    ASSERT(m_effects.isEmpty());
}

void KeyframeEffectStack::addEffect(KeyframeEffect& effect)
{
    // To qualify for membership in an effect stack, an effect must have a target, an animation and a timeline.
    // This method will be called in WebAnimation and KeyframeEffect as those properties change.
    if (!effect.target() || !effect.animation() || !effect.animation()->timeline())
        return;

    m_effects.append(makeWeakPtr(&effect));
    m_isSorted = false;
}

void KeyframeEffectStack::removeEffect(KeyframeEffect& effect)
{
    m_effects.removeFirst(&effect);
}

Vector<WeakPtr<KeyframeEffect>> KeyframeEffectStack::sortedEffects()
{
    ensureEffectsAreSorted();
    return m_effects;
}

void KeyframeEffectStack::ensureEffectsAreSorted()
{
    if (m_isSorted || m_effects.size() < 2)
        return;

    std::sort(m_effects.begin(), m_effects.end(), [&](auto& lhs, auto& rhs) {
        auto* lhsAnimation = lhs->animation();
        auto* rhsAnimation = rhs->animation();

        ASSERT(lhsAnimation);
        ASSERT(rhsAnimation);

        // CSS Transitions sort first.
        bool lhsIsCSSTransition = is<CSSTransition>(lhsAnimation);
        bool rhsIsCSSTransition = is<CSSTransition>(rhsAnimation);
        if (lhsIsCSSTransition || rhsIsCSSTransition) {
            if (lhsIsCSSTransition == rhsIsCSSTransition) {
                // Sort transitions first by their generation time, and then by transition-property.
                // https://drafts.csswg.org/css-transitions-2/#animation-composite-order
                auto* lhsCSSTransition = downcast<CSSTransition>(lhsAnimation);
                auto* rhsCSSTransition = downcast<CSSTransition>(rhsAnimation);
                if (lhsCSSTransition->generationTime() != rhsCSSTransition->generationTime())
                    return lhsCSSTransition->generationTime() < rhsCSSTransition->generationTime();
                return lhsCSSTransition->transitionProperty().utf8() < rhsCSSTransition->transitionProperty().utf8();
            }
            return !rhsIsCSSTransition;
        }

        // CSS Animations sort next.
        bool lhsIsCSSAnimation = is<CSSAnimation>(lhsAnimation);
        bool rhsIsCSSAnimation = is<CSSAnimation>(rhsAnimation);
        if (lhsIsCSSAnimation || rhsIsCSSAnimation) {
            if (lhsIsCSSAnimation == rhsIsCSSAnimation) {
                // https://drafts.csswg.org/css-animations-2/#animation-composite-order
                // Sort A and B based on their position in the computed value of the animation-name property of the (common) owning element.
                auto& lhsCSSAnimationName = downcast<CSSAnimation>(lhsAnimation)->backingAnimation().name();
                auto& rhsCSSAnimationName = downcast<CSSAnimation>(rhsAnimation)->backingAnimation().name();

                for (auto& animationName : m_cssAnimationNames) {
                    if (animationName == lhsCSSAnimationName)
                        return true;
                    if (animationName == rhsCSSAnimationName)
                        return false;
                }
                // We should have found either of those CSS animations in the CSS animations list.
                ASSERT_NOT_REACHED();
            }
            return !rhsIsCSSAnimation;
        }

        // JS-originated animations sort last based on their position in the global animation list.
        // https://drafts.csswg.org/web-animations-1/#animation-composite-order
        return lhsAnimation->globalPosition() < rhsAnimation->globalPosition();
    });

    m_isSorted = true;
}

void KeyframeEffectStack::setCSSAnimationNames(Vector<String>&& animationNames)
{
    m_cssAnimationNames = WTFMove(animationNames);
    // Since the list of animation names has changed, the sorting order of the animation effects may have changed as well.
    m_isSorted = false;
}

} // namespace WebCore