root/Source/core/svg/animation/SMILTimeContainer.cpp

DEFINITIONS

1. m_preventScheduledAnimationsChanges
2. schedule
3. unschedule
4. hasAnimations
5. hasPendingSynchronization
6. notifyIntervalsChanged
7. elapsed
8. isPaused
9. isStarted
10. begin
11. pause
12. resume
13. setElapsed
14. isTimelineRunning
15. scheduleAnimationFrame
16. cancelAnimationFrame
17. scheduleWakeUp
18. wakeupTimerFired
19. updateDocumentOrderIndexes
20. document
21. currentTime
22. serviceOnNextFrame
23. serviceAnimations
24. updateAnimationsAndScheduleFrameIfNeeded
25. updateAnimations

/*
 * Copyright (C) 2008 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.
 */

#include "config.h"
#include "core/svg/animation/SMILTimeContainer.h"

#include "core/animation/AnimationClock.h"
#include "core/animation/DocumentTimeline.h"
#include "core/dom/ElementTraversal.h"
#include "core/frame/FrameView.h"
#include "core/svg/SVGSVGElement.h"
#include "core/svg/animation/SVGSMILElement.h"

using namespace std;

namespace WebCore {

static const double initialFrameDelay = 0.025;

// Every entry-point that calls updateAnimations() should instantiate a
// DiscardScope to prevent deletion of the ownerElement (and hence itself.)
class DiscardScope {
public:
    explicit DiscardScope(SVGSVGElement& timeContainerOwner) : m_discardScopeElement(&timeContainerOwner) { }

private:
    RefPtr<SVGSVGElement> m_discardScopeElement;
};

SMILTimeContainer::SMILTimeContainer(SVGSVGElement& owner)
    : m_beginTime(0)
    , m_pauseTime(0)
    , m_resumeTime(0)
    , m_accumulatedActiveTime(0)
    , m_presetStartTime(0)
    , m_frameSchedulingState(Idle)
    , m_documentOrderIndexesDirty(false)
    , m_wakeupTimer(this, &SMILTimeContainer::wakeupTimerFired)
    , m_ownerSVGElement(owner)
#ifndef NDEBUG
    , m_preventScheduledAnimationsChanges(false)
#endif
{
}

SMILTimeContainer::~SMILTimeContainer()
{
    cancelAnimationFrame();
    ASSERT(!m_wakeupTimer.isActive());
#ifndef NDEBUG
    ASSERT(!m_preventScheduledAnimationsChanges);
#endif
}

void SMILTimeContainer::schedule(SVGSMILElement* animation, SVGElement* target, const QualifiedName& attributeName)
{
    ASSERT(animation->timeContainer() == this);
    ASSERT(target);
    ASSERT(animation->hasValidAttributeName());

#ifndef NDEBUG
    ASSERT(!m_preventScheduledAnimationsChanges);
#endif

    ElementAttributePair key(target, attributeName);
    OwnPtr<AnimationsVector>& scheduled = m_scheduledAnimations.add(key, nullptr).storedValue->value;
    if (!scheduled)
        scheduled = adoptPtr(new AnimationsVector);
    ASSERT(!scheduled->contains(animation));
    scheduled->append(animation);

    SMILTime nextFireTime = animation->nextProgressTime();
    if (nextFireTime.isFinite())
        notifyIntervalsChanged();
}

void SMILTimeContainer::unschedule(SVGSMILElement* animation, SVGElement* target, const QualifiedName& attributeName)
{
    ASSERT(animation->timeContainer() == this);

#ifndef NDEBUG
    ASSERT(!m_preventScheduledAnimationsChanges);
#endif

    ElementAttributePair key(target, attributeName);
    AnimationsVector* scheduled = m_scheduledAnimations.get(key);
    ASSERT(scheduled);
    size_t idx = scheduled->find(animation);
    ASSERT(idx != kNotFound);
    scheduled->remove(idx);
}

bool SMILTimeContainer::hasAnimations() const
{
    return !m_scheduledAnimations.isEmpty();
}

bool SMILTimeContainer::hasPendingSynchronization() const
{
    return m_frameSchedulingState == SynchronizeAnimations && m_wakeupTimer.isActive() && !m_wakeupTimer.nextFireInterval();
}

void SMILTimeContainer::notifyIntervalsChanged()
{
    if (!isStarted())
        return;
    // Schedule updateAnimations() to be called asynchronously so multiple intervals
    // can change with updateAnimations() only called once at the end.
    if (hasPendingSynchronization())
        return;
    cancelAnimationFrame();
    scheduleWakeUp(0, SynchronizeAnimations);
}

SMILTime SMILTimeContainer::elapsed() const
{
    if (!m_beginTime)
        return 0;

    if (isPaused())
        return m_accumulatedActiveTime;

    return currentTime() + m_accumulatedActiveTime - lastResumeTime();
}

bool SMILTimeContainer::isPaused() const
{
    return m_pauseTime;
}

bool SMILTimeContainer::isStarted() const
{
    return m_beginTime;
}

void SMILTimeContainer::begin()
{
    ASSERT(!m_beginTime);
    double now = currentTime();

    // If 'm_presetStartTime' is set, the timeline was modified via setElapsed() before the document began.
    // In this case pass on 'seekToTime=true' to updateAnimations().
    m_beginTime = now - m_presetStartTime;
    DiscardScope discardScope(m_ownerSVGElement);
    SMILTime earliestFireTime = updateAnimations(SMILTime(m_presetStartTime), m_presetStartTime ? true : false);
    m_presetStartTime = 0;

    if (m_pauseTime) {
        m_pauseTime = now;
        // If updateAnimations() caused new syncbase instance to be generated,
        // we don't want to cancel those. Excepting that, no frame should've
        // been scheduled at this point.
        ASSERT(m_frameSchedulingState == Idle || m_frameSchedulingState == SynchronizeAnimations);
    } else if (!hasPendingSynchronization()) {
        ASSERT(isTimelineRunning());
        // If the timeline is running, and there's pending animation updates,
        // always perform the first update after the timeline was started using
        // the wake-up mechanism.
        if (earliestFireTime.isFinite()) {
            SMILTime delay = earliestFireTime - elapsed();
            scheduleWakeUp(std::max(initialFrameDelay, delay.value()), SynchronizeAnimations);
        }
    }
}

void SMILTimeContainer::pause()
{
    ASSERT(!isPaused());
    m_pauseTime = currentTime();

    if (m_beginTime) {
        m_accumulatedActiveTime += m_pauseTime - lastResumeTime();
        cancelAnimationFrame();
    }
    m_resumeTime = 0;
}

void SMILTimeContainer::resume()
{
    ASSERT(isPaused());
    m_resumeTime = currentTime();

    m_pauseTime = 0;
    scheduleWakeUp(0, SynchronizeAnimations);
}

void SMILTimeContainer::setElapsed(SMILTime time)
{
    // If the documment didn't begin yet, record a new start time, we'll seek to once its possible.
    if (!m_beginTime) {
        m_presetStartTime = time.value();
        return;
    }

    cancelAnimationFrame();

    double now = currentTime();
    m_beginTime = now - time.value();
    m_resumeTime = 0;
    if (m_pauseTime) {
        m_pauseTime = now;
        m_accumulatedActiveTime = time.value();
    } else {
        m_accumulatedActiveTime = 0;
    }

#ifndef NDEBUG
    m_preventScheduledAnimationsChanges = true;
#endif
    GroupedAnimationsMap::iterator end = m_scheduledAnimations.end();
    for (GroupedAnimationsMap::iterator it = m_scheduledAnimations.begin(); it != end; ++it) {
        AnimationsVector* scheduled = it->value.get();
        unsigned size = scheduled->size();
        for (unsigned n = 0; n < size; n++)
            scheduled->at(n)->reset();
    }
#ifndef NDEBUG
    m_preventScheduledAnimationsChanges = false;
#endif

    updateAnimationsAndScheduleFrameIfNeeded(time, true);
}

bool SMILTimeContainer::isTimelineRunning() const
{
    return m_beginTime && !isPaused();
}

void SMILTimeContainer::scheduleAnimationFrame(SMILTime fireTime)
{
    ASSERT(isTimelineRunning() && fireTime.isFinite());
    ASSERT(!m_wakeupTimer.isActive());

    SMILTime delay = fireTime - elapsed();
    if (delay.value() < DocumentTimeline::s_minimumDelay) {
        serviceOnNextFrame();
    } else {
        scheduleWakeUp(delay.value() - DocumentTimeline::s_minimumDelay, FutureAnimationFrame);
    }
}

void SMILTimeContainer::cancelAnimationFrame()
{
    m_frameSchedulingState = Idle;
    m_wakeupTimer.stop();
}

void SMILTimeContainer::scheduleWakeUp(double delayTime, FrameSchedulingState frameSchedulingState)
{
    ASSERT(frameSchedulingState == SynchronizeAnimations || frameSchedulingState == FutureAnimationFrame);
    m_wakeupTimer.startOneShot(delayTime, FROM_HERE);
    m_frameSchedulingState = frameSchedulingState;
}

void SMILTimeContainer::wakeupTimerFired(Timer<SMILTimeContainer>*)
{
    ASSERT(m_frameSchedulingState == SynchronizeAnimations || m_frameSchedulingState == FutureAnimationFrame);
    if (m_frameSchedulingState == FutureAnimationFrame) {
        ASSERT(isTimelineRunning());
        m_frameSchedulingState = Idle;
        serviceOnNextFrame();
    } else {
        m_frameSchedulingState = Idle;
        updateAnimationsAndScheduleFrameIfNeeded(elapsed());
    }
}

void SMILTimeContainer::updateDocumentOrderIndexes()
{
    unsigned timingElementCount = 0;
    for (SVGSMILElement* element = Traversal<SVGSMILElement>::firstWithin(m_ownerSVGElement); element; element = Traversal<SVGSMILElement>::next(*element, &m_ownerSVGElement))
        element->setDocumentOrderIndex(timingElementCount++);
    m_documentOrderIndexesDirty = false;
}

struct PriorityCompare {
    PriorityCompare(SMILTime elapsed) : m_elapsed(elapsed) {}
    bool operator()(const RefPtr<SVGSMILElement>& a, const RefPtr<SVGSMILElement>& b)
    {
        // FIXME: This should also consider possible timing relations between the elements.
        SMILTime aBegin = a->intervalBegin();
        SMILTime bBegin = b->intervalBegin();
        // Frozen elements need to be prioritized based on their previous interval.
        aBegin = a->isFrozen() && m_elapsed < aBegin ? a->previousIntervalBegin() : aBegin;
        bBegin = b->isFrozen() && m_elapsed < bBegin ? b->previousIntervalBegin() : bBegin;
        if (aBegin == bBegin)
            return a->documentOrderIndex() < b->documentOrderIndex();
        return aBegin < bBegin;
    }
    SMILTime m_elapsed;
};

Document& SMILTimeContainer::document() const
{
    return m_ownerSVGElement.document();
}

double SMILTimeContainer::currentTime() const
{
    return document().animationClock().currentTime();
}

void SMILTimeContainer::serviceOnNextFrame()
{
    if (document().view()) {
        document().view()->scheduleAnimation();
        m_frameSchedulingState = AnimationFrame;
    }
}

void SMILTimeContainer::serviceAnimations(double monotonicAnimationStartTime)
{
    if (m_frameSchedulingState != AnimationFrame)
        return;

    m_frameSchedulingState = Idle;
    updateAnimationsAndScheduleFrameIfNeeded(elapsed());
}

void SMILTimeContainer::updateAnimationsAndScheduleFrameIfNeeded(SMILTime elapsed, bool seekToTime)
{
    DiscardScope discardScope(m_ownerSVGElement);
    SMILTime earliestFireTime = updateAnimations(elapsed, seekToTime);
    // If updateAnimations() ended up triggering a synchronization (most likely
    // via syncbases), then give that priority.
    if (hasPendingSynchronization())
        return;

    if (!isTimelineRunning())
        return;

    if (!earliestFireTime.isFinite())
        return;

    scheduleAnimationFrame(earliestFireTime);
}

SMILTime SMILTimeContainer::updateAnimations(SMILTime elapsed, bool seekToTime)
{
    SMILTime earliestFireTime = SMILTime::unresolved();

#ifndef NDEBUG
    // This boolean will catch any attempts to schedule/unschedule scheduledAnimations during this critical section.
    // Similarly, any elements removed will unschedule themselves, so this will catch modification of animationsToApply.
    m_preventScheduledAnimationsChanges = true;
#endif

    if (m_documentOrderIndexesDirty)
        updateDocumentOrderIndexes();

    Vector<RefPtr<SVGSMILElement> >  animationsToApply;
    GroupedAnimationsMap::iterator end = m_scheduledAnimations.end();
    for (GroupedAnimationsMap::iterator it = m_scheduledAnimations.begin(); it != end; ++it) {
        AnimationsVector* scheduled = it->value.get();

        // Sort according to priority. Elements with later begin time have higher priority.
        // In case of a tie, document order decides.
        // FIXME: This should also consider timing relationships between the elements. Dependents
        // have higher priority.
        std::sort(scheduled->begin(), scheduled->end(), PriorityCompare(elapsed));

        SVGSMILElement* resultElement = 0;
        unsigned size = scheduled->size();
        for (unsigned n = 0; n < size; n++) {
            SVGSMILElement* animation = scheduled->at(n);
            ASSERT(animation->timeContainer() == this);
            ASSERT(animation->targetElement());
            ASSERT(animation->hasValidAttributeName());

            // Results are accumulated to the first animation that animates and contributes to a particular element/attribute pair.
            // FIXME: we should ensure that resultElement is of an appropriate type.
            if (!resultElement) {
                if (!animation->hasValidAttributeType())
                    continue;
                resultElement = animation;
            }

            // This will calculate the contribution from the animation and add it to the resultsElement.
            if (!animation->progress(elapsed, resultElement, seekToTime) && resultElement == animation)
                resultElement = 0;

            SMILTime nextFireTime = animation->nextProgressTime();
            if (nextFireTime.isFinite())
                earliestFireTime = min(nextFireTime, earliestFireTime);
        }

        if (resultElement)
            animationsToApply.append(resultElement);
    }

    std::sort(animationsToApply.begin(), animationsToApply.end(), PriorityCompare(elapsed));

    unsigned animationsToApplySize = animationsToApply.size();
    if (!animationsToApplySize) {
#ifndef NDEBUG
        m_preventScheduledAnimationsChanges = false;
#endif
        return earliestFireTime;
    }

    // Apply results to target elements.
    for (unsigned i = 0; i < animationsToApplySize; ++i)
        animationsToApply[i]->applyResultsToTarget();

#ifndef NDEBUG
    m_preventScheduledAnimationsChanges = false;
#endif

    for (unsigned i = 0; i < animationsToApplySize; ++i) {
        if (animationsToApply[i]->inDocument() && animationsToApply[i]->isSVGDiscardElement()) {
            RefPtr<SVGSMILElement> animDiscard = animationsToApply[i];
            RefPtr<SVGElement> targetElement = animDiscard->targetElement();
            if (targetElement && targetElement->inDocument()) {
                targetElement->remove(IGNORE_EXCEPTION);
                ASSERT(!targetElement->inDocument());
            }

            if (animDiscard->inDocument()) {
                animDiscard->remove(IGNORE_EXCEPTION);
                ASSERT(!animDiscard->inDocument());
            }
        }
    }
    return earliestFireTime;
}

}