gecko-dev/dom/animation/KeyframeEffect.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/dom/KeyframeEffect.h"

#include "mozilla/dom/KeyframeEffectBinding.h"
#include "mozilla/dom/PropertyIndexedKeyframesBinding.h"
#include "mozilla/AnimationUtils.h"
#include "mozilla/EffectCompositor.h"
#include "mozilla/FloatingPoint.h"
#include "mozilla/LookAndFeel.h" // For LookAndFeel::GetInt
#include "mozilla/StyleAnimationValue.h"
#include "Layers.h" // For Layer
#include "nsCSSParser.h"
#include "nsCSSPropertySet.h"
#include "nsCSSProps.h" // For nsCSSProps::PropHasFlags
#include "nsCSSPseudoElements.h"
#include "nsCSSValue.h"
#include "nsDOMMutationObserver.h" // For nsAutoAnimationMutationBatch
#include "nsStyleUtil.h"
#include <algorithm> // For std::max

namespace mozilla {

// Helper functions for generating a ComputedTimingProperties dictionary
static void
GetComputedTimingDictionary(const ComputedTiming& aComputedTiming,
                            const Nullable<TimeDuration>& aLocalTime,
                            const TimingParams& aTiming,
                            dom::ComputedTimingProperties& aRetVal)
{
  // AnimationEffectTimingProperties
  aRetVal.mDelay = aTiming.mDelay.ToMilliseconds();
  aRetVal.mEndDelay = aTiming.mEndDelay.ToMilliseconds();
  aRetVal.mFill = aComputedTiming.mFill;
  aRetVal.mIterations = aComputedTiming.mIterations;
  aRetVal.mIterationStart = aComputedTiming.mIterationStart;
  aRetVal.mDuration.SetAsUnrestrictedDouble() =
    aComputedTiming.mDuration.ToMilliseconds();
  aRetVal.mDirection = aTiming.mDirection;

  // ComputedTimingProperties
  aRetVal.mActiveDuration = aComputedTiming.mActiveDuration.ToMilliseconds();
  aRetVal.mEndTime = aComputedTiming.mEndTime.ToMilliseconds();
  aRetVal.mLocalTime = AnimationUtils::TimeDurationToDouble(aLocalTime);
  aRetVal.mProgress = aComputedTiming.mProgress;

  if (!aRetVal.mProgress.IsNull()) {
    // Convert the returned currentIteration into Infinity if we set
    // (uint64_t) aComputedTiming.mCurrentIteration to UINT64_MAX
    double iteration = aComputedTiming.mCurrentIteration == UINT64_MAX
                     ? PositiveInfinity<double>()
                     : static_cast<double>(aComputedTiming.mCurrentIteration);
    aRetVal.mCurrentIteration.SetValue(iteration);
  }
}

namespace dom {

NS_IMPL_CYCLE_COLLECTION_INHERITED(KeyframeEffectReadOnly,
                                   AnimationEffectReadOnly,
                                   mTarget,
                                   mAnimation)

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(KeyframeEffectReadOnly,
                                               AnimationEffectReadOnly)
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(KeyframeEffectReadOnly)
NS_INTERFACE_MAP_END_INHERITING(AnimationEffectReadOnly)

NS_IMPL_ADDREF_INHERITED(KeyframeEffectReadOnly, AnimationEffectReadOnly)
NS_IMPL_RELEASE_INHERITED(KeyframeEffectReadOnly, AnimationEffectReadOnly)

KeyframeEffectReadOnly::KeyframeEffectReadOnly(
  nsIDocument* aDocument,
  Element* aTarget,
  CSSPseudoElementType aPseudoType,
  const TimingParams& aTiming)
  : KeyframeEffectReadOnly(aDocument, aTarget, aPseudoType,
                           new AnimationEffectTimingReadOnly(aTiming))
{
}

KeyframeEffectReadOnly::KeyframeEffectReadOnly(
  nsIDocument* aDocument,
  Element* aTarget,
  CSSPseudoElementType aPseudoType,
  AnimationEffectTimingReadOnly* aTiming)
  : AnimationEffectReadOnly(aDocument)
  , mTarget(aTarget)
  , mTiming(*aTiming)
  , mPseudoType(aPseudoType)
  , mInEffectOnLastAnimationTimingUpdate(false)
{
  MOZ_ASSERT(aTiming);
  MOZ_ASSERT(aTarget, "null animation target is not yet supported");
}

JSObject*
KeyframeEffectReadOnly::WrapObject(JSContext* aCx,
                                   JS::Handle<JSObject*> aGivenProto)
{
  return KeyframeEffectReadOnlyBinding::Wrap(aCx, this, aGivenProto);
}

IterationCompositeOperation
KeyframeEffectReadOnly::IterationComposite() const
{
  return IterationCompositeOperation::Replace;
}

CompositeOperation
KeyframeEffectReadOnly::Composite() const
{
  return CompositeOperation::Replace;
}

already_AddRefed<AnimationEffectTimingReadOnly>
KeyframeEffectReadOnly::Timing() const
{
  RefPtr<AnimationEffectTimingReadOnly> temp(mTiming);
  return temp.forget();
}

void
KeyframeEffectReadOnly::SetSpecifiedTiming(const TimingParams& aTiming)
{
  if (mTiming->AsTimingParams() == aTiming) {
    return;
  }
  mTiming->SetTimingParams(aTiming);
  if (mAnimation) {
    mAnimation->NotifyEffectTimingUpdated();
  }
  // NotifyEffectTimingUpdated will eventually cause
  // NotifyAnimationTimingUpdated to be called on this object which will
  // update our registration with the target element.
}

void
KeyframeEffectReadOnly::NotifyAnimationTimingUpdated()
{
  UpdateTargetRegistration();

  // If the effect is not relevant it will be removed from the target
  // element's effect set. However, effects not in the effect set
  // will not be included in the set of candidate effects for running on
  // the compositor and hence they won't have their compositor status
  // updated. As a result, we need to make sure we clear their compositor
  // status here.
  bool isRelevant = mAnimation && mAnimation->IsRelevant();
  if (!isRelevant) {
    ResetIsRunningOnCompositor();
  }

  // Detect changes to "in effect" status since we need to recalculate the
  // animation cascade for this element whenever that changes.
  bool inEffect = IsInEffect();
  if (inEffect != mInEffectOnLastAnimationTimingUpdate) {
    if (mTarget) {
      EffectSet* effectSet = EffectSet::GetEffectSet(mTarget, mPseudoType);
      if (effectSet) {
        effectSet->MarkCascadeNeedsUpdate();
      }
    }
    mInEffectOnLastAnimationTimingUpdate = inEffect;
  }

  // Request restyle if necessary.
  //
  // Bug 1235002: We should skip requesting a restyle when mProperties is empty.
  // However, currently we don't properly encapsulate mProperties so we can't
  // detect when it changes. As a result, if we skip requesting restyles when
  // mProperties is empty and we play an animation and *then* add properties to
  // it (as we currently do when building CSS animations), we will fail to
  // request a restyle at all. Since animations without properties are rare, we
  // currently just request the restyle regardless of whether mProperties is
  // empty or not.
  //
  // Bug 1216843: When we implement iteration composite modes, we need to
  // also detect if the current iteration has changed.
  if (mAnimation && GetComputedTiming().mProgress != mProgressOnLastCompose) {
    EffectCompositor::RestyleType restyleType =
      CanThrottle() ?
      EffectCompositor::RestyleType::Throttled :
      EffectCompositor::RestyleType::Standard;
    nsPresContext* presContext = GetPresContext();
    if (presContext) {
      presContext->EffectCompositor()->
        RequestRestyle(mTarget, mPseudoType, restyleType,
                       mAnimation->CascadeLevel());
    }

    // If we're not relevant, we will have been removed from the EffectSet.
    // As a result, when the restyle we requested above is fulfilled, our
    // ComposeStyle will not get called and mProgressOnLastCompose will not
    // be updated. Instead, we need to manually clear it.
    if (!isRelevant) {
      mProgressOnLastCompose.SetNull();
    }
  }
}

Nullable<TimeDuration>
KeyframeEffectReadOnly::GetLocalTime() const
{
  // Since the *animation* start time is currently always zero, the local
  // time is equal to the parent time.
  Nullable<TimeDuration> result;
  if (mAnimation) {
    result = mAnimation->GetCurrentTime();
  }
  return result;
}

void
KeyframeEffectReadOnly::GetComputedTimingAsDict(ComputedTimingProperties& aRetVal) const
{
  const Nullable<TimeDuration> currentTime = GetLocalTime();
  GetComputedTimingDictionary(GetComputedTimingAt(currentTime,
                                                  SpecifiedTiming()),
                              currentTime,
                              SpecifiedTiming(),
                              aRetVal);
}

ComputedTiming
KeyframeEffectReadOnly::GetComputedTimingAt(
                          const Nullable<TimeDuration>& aLocalTime,
                          const TimingParams& aTiming)
{
  const StickyTimeDuration zeroDuration;

  // Always return the same object to benefit from return-value optimization.
  ComputedTiming result;

  if (aTiming.mDuration) {
    MOZ_ASSERT(aTiming.mDuration.ref() >= zeroDuration,
               "Iteration duration should be positive");
    result.mDuration = aTiming.mDuration.ref();
  }

  result.mIterations = IsNaN(aTiming.mIterations) || aTiming.mIterations < 0.0f ?
                       1.0f :
                       aTiming.mIterations;
  result.mIterationStart = std::max(aTiming.mIterationStart, 0.0);

  result.mActiveDuration = ActiveDuration(result.mDuration, result.mIterations);
  result.mEndTime = aTiming.mDelay + result.mActiveDuration +
                    aTiming.mEndDelay;
  result.mFill = aTiming.mFill == dom::FillMode::Auto ?
                 dom::FillMode::None :
                 aTiming.mFill;

  // The default constructor for ComputedTiming sets all other members to
  // values consistent with an animation that has not been sampled.
  if (aLocalTime.IsNull()) {
    return result;
  }
  const TimeDuration& localTime = aLocalTime.Value();

  // When we finish exactly at the end of an iteration we need to report
  // the end of the final iteration and not the start of the next iteration
  // so we set up a flag for that case.
  bool isEndOfFinalIteration = false;

  // Get the normalized time within the active interval.
  StickyTimeDuration activeTime;
  if (localTime >=
        std::min(StickyTimeDuration(aTiming.mDelay + result.mActiveDuration),
                 result.mEndTime)) {
    result.mPhase = ComputedTiming::AnimationPhase::After;
    if (!result.FillsForwards()) {
      // The animation isn't active or filling at this time.
      result.mProgress.SetNull();
      return result;
    }
    activeTime = result.mActiveDuration;
    double finiteProgress =
      (IsInfinite(result.mIterations) ? 0.0 : result.mIterations)
      + result.mIterationStart;
    isEndOfFinalIteration = result.mIterations != 0.0 &&
                            fmod(finiteProgress, 1.0) == 0;
  } else if (localTime <
               std::min(StickyTimeDuration(aTiming.mDelay), result.mEndTime)) {
    result.mPhase = ComputedTiming::AnimationPhase::Before;
    if (!result.FillsBackwards()) {
      // The animation isn't active or filling at this time.
      result.mProgress.SetNull();
      return result;
    }
    // activeTime is zero
  } else {
    MOZ_ASSERT(result.mActiveDuration != zeroDuration,
               "How can we be in the middle of a zero-duration interval?");
    result.mPhase = ComputedTiming::AnimationPhase::Active;
    activeTime = localTime - aTiming.mDelay;
  }

  // Calculate the scaled active time
  // (We handle the case where the iterationStart is zero separately in case
  // the duration is infinity, since 0 * Infinity is undefined.)
  StickyTimeDuration startOffset =
    result.mIterationStart == 0.0
    ? StickyTimeDuration(0)
    : result.mDuration.MultDouble(result.mIterationStart);
  StickyTimeDuration scaledActiveTime = activeTime + startOffset;

  // Get the position within the current iteration.
  StickyTimeDuration iterationTime;
  if (result.mDuration != zeroDuration &&
      scaledActiveTime != StickyTimeDuration::Forever()) {
    iterationTime = isEndOfFinalIteration
                    ? result.mDuration
      : scaledActiveTime % result.mDuration;
  } /* else, either the duration is zero and iterationTime is zero,
       or the scaledActiveTime is infinity in which case the iterationTime
       should become infinity but we will not use the iterationTime in that
       case so we just leave it as zero */

  // Determine the 0-based index of the current iteration.
  if (result.mPhase == ComputedTiming::AnimationPhase::Before ||
      result.mIterations == 0) {
    result.mCurrentIteration = static_cast<uint64_t>(result.mIterationStart);
  } else if (result.mPhase == ComputedTiming::AnimationPhase::After) {
    result.mCurrentIteration =
      IsInfinite(result.mIterations)
      ? UINT64_MAX // In GetComputedTimingDictionary(), we will convert this
                   // into Infinity.
      : static_cast<uint64_t>(ceil(result.mIterations +
                              result.mIterationStart)) - 1;
  } else if (result.mDuration == StickyTimeDuration::Forever()) {
    result.mCurrentIteration = static_cast<uint64_t>(result.mIterationStart);
  } else {
    result.mCurrentIteration =
      static_cast<uint64_t>(scaledActiveTime / result.mDuration); // floor
  }

  // Normalize the iteration time into a fraction of the iteration duration.
  if (result.mPhase == ComputedTiming::AnimationPhase::Before ||
      result.mIterations == 0) {
    double progress = fmod(result.mIterationStart, 1.0);
    result.mProgress.SetValue(progress);
  } else if (result.mPhase == ComputedTiming::AnimationPhase::After) {
    double progress;
    if (isEndOfFinalIteration) {
      progress = 1.0;
    } else if (IsInfinite(result.mIterations)) {
      progress = fmod(result.mIterationStart, 1.0);
    } else {
      progress = fmod(result.mIterations + result.mIterationStart, 1.0);
    }
    result.mProgress.SetValue(progress);
  } else {
    // We are in the active phase so the iteration duration can't be zero.
    MOZ_ASSERT(result.mDuration != zeroDuration,
               "In the active phase of a zero-duration animation?");
    double progress = result.mDuration == StickyTimeDuration::Forever()
                      ? fmod(result.mIterationStart, 1.0)
                      : iterationTime / result.mDuration;
    result.mProgress.SetValue(progress);
  }

  bool thisIterationReverse = false;
  switch (aTiming.mDirection) {
    case PlaybackDirection::Normal:
      thisIterationReverse = false;
      break;
    case PlaybackDirection::Reverse:
      thisIterationReverse = true;
      break;
    case PlaybackDirection::Alternate:
      thisIterationReverse = (result.mCurrentIteration & 1) == 1;
      break;
    case PlaybackDirection::Alternate_reverse:
      thisIterationReverse = (result.mCurrentIteration & 1) == 0;
      break;
    default:
      MOZ_ASSERT(true, "Unknown PlaybackDirection type");
  }
  if (thisIterationReverse) {
    result.mProgress.SetValue(1.0 - result.mProgress.Value());
  }

  if (aTiming.mFunction) {
    result.mProgress.SetValue(
      aTiming.mFunction->GetValue(result.mProgress.Value()));
  }

  return result;
}

StickyTimeDuration
KeyframeEffectReadOnly::ActiveDuration(
  const StickyTimeDuration& aIterationDuration,
  double aIterationCount)
{
  // If either the iteration duration or iteration count is zero,
  // Web Animations says that the active duration is zero. This is to
  // ensure that the result is defined when the other argument is Infinity.
  const StickyTimeDuration zeroDuration;
  if (aIterationDuration == zeroDuration ||
      aIterationCount == 0.0) {
    return zeroDuration;
  }

  return aIterationDuration.MultDouble(aIterationCount);
}

// https://w3c.github.io/web-animations/#in-play
bool
KeyframeEffectReadOnly::IsInPlay() const
{
  if (!mAnimation || mAnimation->PlayState() == AnimationPlayState::Finished) {
    return false;
  }

  return GetComputedTiming().mPhase == ComputedTiming::AnimationPhase::Active;
}

// https://w3c.github.io/web-animations/#current
bool
KeyframeEffectReadOnly::IsCurrent() const
{
  if (!mAnimation || mAnimation->PlayState() == AnimationPlayState::Finished) {
    return false;
  }

  ComputedTiming computedTiming = GetComputedTiming();
  return computedTiming.mPhase == ComputedTiming::AnimationPhase::Before ||
         computedTiming.mPhase == ComputedTiming::AnimationPhase::Active;
}

// https://w3c.github.io/web-animations/#in-effect
bool
KeyframeEffectReadOnly::IsInEffect() const
{
  ComputedTiming computedTiming = GetComputedTiming();
  return !computedTiming.mProgress.IsNull();
}

void
KeyframeEffectReadOnly::SetAnimation(Animation* aAnimation)
{
  mAnimation = aAnimation;
  NotifyAnimationTimingUpdated();
}

const AnimationProperty*
KeyframeEffectReadOnly::GetAnimationOfProperty(nsCSSProperty aProperty) const
{
  for (size_t propIdx = 0, propEnd = mProperties.Length();
       propIdx != propEnd; ++propIdx) {
    if (aProperty == mProperties[propIdx].mProperty) {
      const AnimationProperty* result = &mProperties[propIdx];
      if (!result->mWinsInCascade) {
        result = nullptr;
      }
      return result;
    }
  }
  return nullptr;
}

bool
KeyframeEffectReadOnly::HasAnimationOfProperties(
                          const nsCSSProperty* aProperties,
                          size_t aPropertyCount) const
{
  for (size_t i = 0; i < aPropertyCount; i++) {
    if (HasAnimationOfProperty(aProperties[i])) {
      return true;
    }
  }
  return false;
}

bool
KeyframeEffectReadOnly::UpdateProperties(
    const InfallibleTArray<AnimationProperty>& aProperties)
{
  // AnimationProperty::operator== does not compare mWinsInCascade and
  // mIsRunningOnCompositor, we don't need to update anything here because
  // we want to preserve
  if (mProperties == aProperties) {
    return false;
  }

  nsCSSPropertySet winningInCascadeProperties;
  nsCSSPropertySet runningOnCompositorProperties;

  for (const AnimationProperty& property : mProperties) {
    if (property.mWinsInCascade) {
      winningInCascadeProperties.AddProperty(property.mProperty);
    }
    if (property.mIsRunningOnCompositor) {
      runningOnCompositorProperties.AddProperty(property.mProperty);
    }
  }

  mProperties = aProperties;

  for (AnimationProperty& property : mProperties) {
    property.mWinsInCascade =
      winningInCascadeProperties.HasProperty(property.mProperty);
    property.mIsRunningOnCompositor =
      runningOnCompositorProperties.HasProperty(property.mProperty);
  }

  if (mAnimation) {
    nsPresContext* presContext = GetPresContext();
    if (presContext) {
      presContext->EffectCompositor()->
        RequestRestyle(mTarget, mPseudoType,
                       EffectCompositor::RestyleType::Layer,
                       mAnimation->CascadeLevel());
    }
  }

  return true;
}

void
KeyframeEffectReadOnly::ComposeStyle(RefPtr<AnimValuesStyleRule>& aStyleRule,
                                     nsCSSPropertySet& aSetProperties)
{
  ComputedTiming computedTiming = GetComputedTiming();
  mProgressOnLastCompose = computedTiming.mProgress;

  // If the progress is null, we don't have fill data for the current
  // time so we shouldn't animate.
  if (computedTiming.mProgress.IsNull()) {
    return;
  }

  for (size_t propIdx = 0, propEnd = mProperties.Length();
       propIdx != propEnd; ++propIdx)
  {
    const AnimationProperty& prop = mProperties[propIdx];

    MOZ_ASSERT(prop.mSegments[0].mFromKey == 0.0, "incorrect first from key");
    MOZ_ASSERT(prop.mSegments[prop.mSegments.Length() - 1].mToKey == 1.0,
               "incorrect last to key");

    if (aSetProperties.HasProperty(prop.mProperty)) {
      // Animations are composed by EffectCompositor by iterating
      // from the last animation to first. For animations targetting the
      // same property, the later one wins. So if this property is already set,
      // we should not override it.
      continue;
    }

    if (!prop.mWinsInCascade) {
      // This isn't the winning declaration, so don't add it to style.
      // For transitions, this is important, because it's how we
      // implement the rule that CSS transitions don't run when a CSS
      // animation is running on the same property and element.  For
      // animations, this is only skipping things that will otherwise be
      // overridden.
      continue;
    }

    aSetProperties.AddProperty(prop.mProperty);

    MOZ_ASSERT(prop.mSegments.Length() > 0,
               "property should not be in animations if it has no segments");

    // FIXME: Maybe cache the current segment?
    const AnimationPropertySegment *segment = prop.mSegments.Elements(),
                                *segmentEnd = segment + prop.mSegments.Length();
    while (segment->mToKey < computedTiming.mProgress.Value()) {
      MOZ_ASSERT(segment->mFromKey < segment->mToKey, "incorrect keys");
      if ((segment+1) == segmentEnd) {
        break;
      }
      ++segment;
      MOZ_ASSERT(segment->mFromKey == (segment-1)->mToKey, "incorrect keys");
    }
    MOZ_ASSERT(segment->mFromKey < segment->mToKey, "incorrect keys");
    MOZ_ASSERT(segment >= prop.mSegments.Elements() &&
               size_t(segment - prop.mSegments.Elements()) <
                 prop.mSegments.Length(),
               "out of array bounds");

    if (!aStyleRule) {
      // Allocate the style rule now that we know we have animation data.
      aStyleRule = new AnimValuesStyleRule();
    }

    double positionInSegment =
      (computedTiming.mProgress.Value() - segment->mFromKey) /
      (segment->mToKey - segment->mFromKey);
    double valuePosition =
      ComputedTimingFunction::GetPortion(segment->mTimingFunction,
                                         positionInSegment);

    StyleAnimationValue *val = aStyleRule->AddEmptyValue(prop.mProperty);

#ifdef DEBUG
    bool result =
#endif
      StyleAnimationValue::Interpolate(prop.mProperty,
                                       segment->mFromValue,
                                       segment->mToValue,
                                       valuePosition, *val);
    MOZ_ASSERT(result, "interpolate must succeed now");
  }
}

bool
KeyframeEffectReadOnly::IsRunningOnCompositor() const
{
  // We consider animation is running on compositor if there is at least
  // one property running on compositor.
  // Animation.IsRunningOnCompotitor will return more fine grained
  // information in bug 1196114.
  for (const AnimationProperty& property : mProperties) {
    if (property.mIsRunningOnCompositor) {
      return true;
    }
  }
  return false;
}

void
KeyframeEffectReadOnly::SetIsRunningOnCompositor(nsCSSProperty aProperty,
                                                 bool aIsRunning)
{
  MOZ_ASSERT(nsCSSProps::PropHasFlags(aProperty,
                                      CSS_PROPERTY_CAN_ANIMATE_ON_COMPOSITOR),
             "Property being animated on compositor is a recognized "
             "compositor-animatable property");
  for (AnimationProperty& property : mProperties) {
    if (property.mProperty == aProperty) {
      property.mIsRunningOnCompositor = aIsRunning;
      // We currently only set a performance warning message when animations
      // cannot be run on the compositor, so if this animation is running
      // on the compositor we don't need a message.
      if (aIsRunning) {
        property.mPerformanceWarning.reset();
      }
      return;
    }
  }
}

KeyframeEffectReadOnly::~KeyframeEffectReadOnly()
{
}

template <class KeyframeEffectType, class OptionsType>
/* static */ already_AddRefed<KeyframeEffectType>
KeyframeEffectReadOnly::ConstructKeyframeEffect(
    const GlobalObject& aGlobal,
    const Nullable<ElementOrCSSPseudoElement>& aTarget,
    JS::Handle<JSObject*> aFrames,
    const OptionsType& aOptions,
    ErrorResult& aRv)
{
  nsIDocument* doc = AnimationUtils::GetCurrentRealmDocument(aGlobal.Context());
  if (!doc) {
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }

  TimingParams timingParams =
    TimingParams::FromOptionsUnion(aOptions, doc, aRv);
  if (aRv.Failed()) {
    return nullptr;
  }

  return ConstructKeyframeEffect<KeyframeEffectType>(
    aGlobal, aTarget, aFrames, timingParams, aRv);
}

template <class KeyframeEffectType>
/* static */ already_AddRefed<KeyframeEffectType>
KeyframeEffectReadOnly::ConstructKeyframeEffect(
    const GlobalObject& aGlobal,
    const Nullable<ElementOrCSSPseudoElement>& aTarget,
    JS::Handle<JSObject*> aFrames,
    const TimingParams& aTiming,
    ErrorResult& aRv)
{
  if (aTarget.IsNull()) {
    // We don't support null targets yet.
    aRv.Throw(NS_ERROR_DOM_ANIM_NO_TARGET_ERR);
    return nullptr;
  }

  const ElementOrCSSPseudoElement& target = aTarget.Value();
  MOZ_ASSERT(target.IsElement() || target.IsCSSPseudoElement(),
             "Uninitialized target");

  RefPtr<Element> targetElement;
  CSSPseudoElementType pseudoType = CSSPseudoElementType::NotPseudo;
  if (target.IsElement()) {
    targetElement = &target.GetAsElement();
  } else {
    targetElement = target.GetAsCSSPseudoElement().ParentElement();
    pseudoType = target.GetAsCSSPseudoElement().GetType();
  }

  if (!targetElement->GetComposedDoc()) {
    aRv.Throw(NS_ERROR_DOM_ANIM_TARGET_NOT_IN_DOC_ERR);
    return nullptr;
  }

  InfallibleTArray<AnimationProperty> animationProperties;
  BuildAnimationPropertyList(aGlobal.Context(), targetElement, pseudoType,
                             aFrames, animationProperties, aRv);

  if (aRv.Failed()) {
    return nullptr;
  }

  RefPtr<KeyframeEffectType> effect =
    new KeyframeEffectType(targetElement->OwnerDoc(), targetElement,
                           pseudoType, aTiming);
  effect->mProperties = Move(animationProperties);
  return effect.forget();
}

void
KeyframeEffectReadOnly::ResetIsRunningOnCompositor()
{
  for (AnimationProperty& property : mProperties) {
    property.mIsRunningOnCompositor = false;
  }
}

void
KeyframeEffectReadOnly::UpdateTargetRegistration()
{
  if (!mTarget) {
    return;
  }

  bool isRelevant = mAnimation && mAnimation->IsRelevant();

  // Animation::IsRelevant() returns a cached value. It only updates when
  // something calls Animation::UpdateRelevance. Whenever our timing changes,
  // we should be notifying our Animation before calling this, so
  // Animation::IsRelevant() should be up-to-date by the time we get here.
  MOZ_ASSERT(isRelevant == IsCurrent() || IsInEffect(),
             "Out of date Animation::IsRelevant value");

  if (isRelevant) {
    EffectSet* effectSet = EffectSet::GetOrCreateEffectSet(mTarget,
                                                           mPseudoType);
    effectSet->AddEffect(*this);
  } else {
    EffectSet* effectSet = EffectSet::GetEffectSet(mTarget, mPseudoType);
    if (effectSet) {
      effectSet->RemoveEffect(*this);
      if (effectSet->IsEmpty()) {
        EffectSet::DestroyEffectSet(mTarget, mPseudoType);
      }
    }
  }
}

#ifdef DEBUG
void
DumpAnimationProperties(nsTArray<AnimationProperty>& aAnimationProperties)
{
  for (auto& p : aAnimationProperties) {
    printf("%s\n", nsCSSProps::GetStringValue(p.mProperty).get());
    for (auto& s : p.mSegments) {
      nsString fromValue, toValue;
      StyleAnimationValue::UncomputeValue(p.mProperty,
                                          s.mFromValue,
                                          fromValue);
      StyleAnimationValue::UncomputeValue(p.mProperty,
                                          s.mToValue,
                                          toValue);
      printf("  %f..%f: %s..%s\n", s.mFromKey, s.mToKey,
             NS_ConvertUTF16toUTF8(fromValue).get(),
             NS_ConvertUTF16toUTF8(toValue).get());
    }
  }
}
#endif

/**
 * A property and StyleAnimationValue pair.
 */
struct KeyframeValue
{
  nsCSSProperty mProperty;
  StyleAnimationValue mValue;
};

/**
 * Represents a relative position for a value in a keyframe animation.
 */
enum class ValuePosition
{
  First,  // value at 0 used for reverse filling
  Left,   // value coming in to a given offset
  Right,  // value coming out from a given offset
  Last    // value at 1 used for forward filling
};

/**
 * A single value in a keyframe animation, used by GetFrames to produce a
 * minimal set of Keyframe objects.
 */
struct OrderedKeyframeValueEntry : KeyframeValue
{
  float mOffset;
  const Maybe<ComputedTimingFunction>* mTimingFunction;
  ValuePosition mPosition;

  bool SameKeyframe(const OrderedKeyframeValueEntry& aOther) const
  {
    return mOffset == aOther.mOffset &&
           !!mTimingFunction == !!aOther.mTimingFunction &&
           (!mTimingFunction || *mTimingFunction == *aOther.mTimingFunction) &&
           mPosition == aOther.mPosition;
  }

  struct ForKeyframeGenerationComparator
  {
    static bool Equals(const OrderedKeyframeValueEntry& aLhs,
                       const OrderedKeyframeValueEntry& aRhs)
    {
      return aLhs.SameKeyframe(aRhs) &&
             aLhs.mProperty == aRhs.mProperty;
    }
    static bool LessThan(const OrderedKeyframeValueEntry& aLhs,
                         const OrderedKeyframeValueEntry& aRhs)
    {
      // First, sort by offset.
      if (aLhs.mOffset != aRhs.mOffset) {
        return aLhs.mOffset < aRhs.mOffset;
      }

      // Second, by position.
      if (aLhs.mPosition != aRhs.mPosition) {
        return aLhs.mPosition < aRhs.mPosition;
      }

      // Third, by easing.
      if (aLhs.mTimingFunction) {
        if (aRhs.mTimingFunction) {
          int32_t order =
            ComputedTimingFunction::Compare(*aLhs.mTimingFunction,
                                            *aRhs.mTimingFunction);
          if (order != 0) {
            return order < 0;
          }
        } else {
          return true;
        }
      } else {
        if (aRhs.mTimingFunction) {
          return false;
        }
      }

      // Last, by property IDL name.
      return nsCSSProps::PropertyIDLNameSortPosition(aLhs.mProperty) <
             nsCSSProps::PropertyIDLNameSortPosition(aRhs.mProperty);
    }
  };
};

/**
 * Data for a segment in a keyframe animation of a given property
 * whose value is a StyleAnimationValue.
 *
 * KeyframeValueEntry is used in BuildAnimationPropertyListFromKeyframeSequence
 * to gather data for each individual segment described by an author-supplied
 * an IDL sequence<Keyframe> value so that they can be parsed into mProperties.
 */
struct KeyframeValueEntry : KeyframeValue
{
  float mOffset;
  Maybe<ComputedTimingFunction> mTimingFunction;

  struct PropertyOffsetComparator
  {
    static bool Equals(const KeyframeValueEntry& aLhs,
                       const KeyframeValueEntry& aRhs)
    {
      return aLhs.mProperty == aRhs.mProperty &&
             aLhs.mOffset == aRhs.mOffset;
    }
    static bool LessThan(const KeyframeValueEntry& aLhs,
                         const KeyframeValueEntry& aRhs)
    {
      // First, sort by property IDL name.
      int32_t order = nsCSSProps::PropertyIDLNameSortPosition(aLhs.mProperty) -
                      nsCSSProps::PropertyIDLNameSortPosition(aRhs.mProperty);
      if (order != 0) {
        return order < 0;
      }

      // Then, by offset.
      return aLhs.mOffset < aRhs.mOffset;
    }
  };
};

/**
 * A property-values pair obtained from the open-ended properties
 * discovered on a Keyframe or PropertyIndexedKeyframes object.
 *
 * Single values (as required by Keyframe, and as also supported
 * on PropertyIndexedKeyframes) are stored as the only element in
 * mValues.
 */
struct PropertyValuesPair
{
  nsCSSProperty mProperty;
  nsTArray<nsString> mValues;

  class PropertyPriorityComparator
  {
  public:
    PropertyPriorityComparator()
      : mSubpropertyCountInitialized(false) {}

    bool Equals(const PropertyValuesPair& aLhs,
                const PropertyValuesPair& aRhs) const
    {
      return aLhs.mProperty == aRhs.mProperty;
    }

    bool LessThan(const PropertyValuesPair& aLhs,
                  const PropertyValuesPair& aRhs) const
    {
      bool isShorthandLhs = nsCSSProps::IsShorthand(aLhs.mProperty);
      bool isShorthandRhs = nsCSSProps::IsShorthand(aRhs.mProperty);

      if (isShorthandLhs) {
        if (isShorthandRhs) {
          // First, sort shorthands by the number of longhands they have.
          uint32_t subpropCountLhs = SubpropertyCount(aLhs.mProperty);
          uint32_t subpropCountRhs = SubpropertyCount(aRhs.mProperty);
          if (subpropCountLhs != subpropCountRhs) {
            return subpropCountLhs < subpropCountRhs;
          }
          // Otherwise, sort by IDL name below.
        } else {
          // Put longhands before shorthands.
          return false;
        }
      } else {
        if (isShorthandRhs) {
          // Put longhands before shorthands.
          return true;
        }
      }
      // For two longhand properties, or two shorthand with the same number
      // of longhand components, sort by IDL name.
      return nsCSSProps::PropertyIDLNameSortPosition(aLhs.mProperty) <
             nsCSSProps::PropertyIDLNameSortPosition(aRhs.mProperty);
    }

    uint32_t SubpropertyCount(nsCSSProperty aProperty) const
    {
      if (!mSubpropertyCountInitialized) {
        PodZero(&mSubpropertyCount);
        mSubpropertyCountInitialized = true;
      }
      if (mSubpropertyCount[aProperty] == 0) {
        uint32_t count = 0;
        CSSPROPS_FOR_SHORTHAND_SUBPROPERTIES(
            p, aProperty, nsCSSProps::eEnabledForAllContent) {
          ++count;
        }
        mSubpropertyCount[aProperty] = count;
      }
      return mSubpropertyCount[aProperty];
    }

  private:
    // Cache of shorthand subproperty counts.
    mutable RangedArray<
      uint32_t,
      eCSSProperty_COUNT_no_shorthands,
      eCSSProperty_COUNT - eCSSProperty_COUNT_no_shorthands> mSubpropertyCount;
    mutable bool mSubpropertyCountInitialized;
  };
};

/**
 * The result of parsing a JS object as a Keyframe dictionary
 * and getting its property-value pairs from its open-ended
 * properties.
 */
struct OffsetIndexedKeyframe
{
  binding_detail::FastKeyframe mKeyframeDict;
  nsTArray<PropertyValuesPair> mPropertyValuePairs;
};

/**
 * An additional property (for a property-values pair) found on a Keyframe
 * or PropertyIndexedKeyframes object.
 */
struct AdditionalProperty
{
  nsCSSProperty mProperty;
  size_t mJsidIndex;        // Index into |ids| in GetPropertyValuesPairs.

  struct PropertyComparator
  {
    bool Equals(const AdditionalProperty& aLhs,
                const AdditionalProperty& aRhs) const
    {
      return aLhs.mProperty == aRhs.mProperty;
    }
    bool LessThan(const AdditionalProperty& aLhs,
                  const AdditionalProperty& aRhs) const
    {
      return nsCSSProps::PropertyIDLNameSortPosition(aLhs.mProperty) <
             nsCSSProps::PropertyIDLNameSortPosition(aRhs.mProperty);
    }
  };
};

/**
 * Converts aValue to DOMString and appends it to aValues.
 */
static bool
AppendValueAsString(JSContext* aCx,
                    nsTArray<nsString>& aValues,
                    JS::Handle<JS::Value> aValue)
{
  return ConvertJSValueToString(aCx, aValue, eStringify, eStringify,
                                *aValues.AppendElement());
}

// For the aAllowList parameter of AppendStringOrStringSequence and
// GetPropertyValuesPairs.
enum class ListAllowance { eDisallow, eAllow };

/**
 * Converts aValue to DOMString, if aAllowLists is eDisallow, or
 * to (DOMString or sequence<DOMString>) if aAllowLists is aAllow.
 * The resulting strings are appended to aValues.
 */
static bool
AppendStringOrStringSequenceToArray(JSContext* aCx,
                                    JS::Handle<JS::Value> aValue,
                                    ListAllowance aAllowLists,
                                    nsTArray<nsString>& aValues)
{
  if (aAllowLists == ListAllowance::eAllow && aValue.isObject()) {
    // The value is an object, and we want to allow lists; convert
    // aValue to (DOMString or sequence<DOMString>).
    JS::ForOfIterator iter(aCx);
    if (!iter.init(aValue, JS::ForOfIterator::AllowNonIterable)) {
      return false;
    }
    if (iter.valueIsIterable()) {
      // If the object is iterable, convert it to sequence<DOMString>.
      JS::Rooted<JS::Value> element(aCx);
      for (;;) {
        bool done;
        if (!iter.next(&element, &done)) {
          return false;
        }
        if (done) {
          break;
        }
        if (!AppendValueAsString(aCx, aValues, element)) {
          return false;
        }
      }
      return true;
    }
  }

  // Either the object is not iterable, or aAllowLists doesn't want
  // a list; convert it to DOMString.
  if (!AppendValueAsString(aCx, aValues, aValue)) {
    return false;
  }

  return true;
}

/**
 * Reads the property-values pairs from the specified JS object.
 *
 * @param aObject The JS object to look at.
 * @param aAllowLists If eAllow, values will be converted to
 *   (DOMString or sequence<DOMString); if eDisallow, values
 *   will be converted to DOMString.
 * @param aResult The array into which the enumerated property-values
 *   pairs will be stored.
 * @return false on failure or JS exception thrown while interacting
 *   with aObject; true otherwise.
 */
static bool
GetPropertyValuesPairs(JSContext* aCx,
                       JS::Handle<JSObject*> aObject,
                       ListAllowance aAllowLists,
                       nsTArray<PropertyValuesPair>& aResult)
{
  nsTArray<AdditionalProperty> properties;

  // Iterate over all the properties on aObject and append an
  // entry to properties for them.
  //
  // We don't compare the jsids that we encounter with those for
  // the explicit dictionary members, since we know that none
  // of the CSS property IDL names clash with them.
  JS::Rooted<JS::IdVector> ids(aCx, JS::IdVector(aCx));
  if (!JS_Enumerate(aCx, aObject, &ids)) {
    return false;
  }
  for (size_t i = 0, n = ids.length(); i < n; i++) {
    nsAutoJSString propName;
    if (!propName.init(aCx, ids[i])) {
      return false;
    }
    nsCSSProperty property =
      nsCSSProps::LookupPropertyByIDLName(propName,
                                          nsCSSProps::eEnabledForAllContent);
    if (property != eCSSProperty_UNKNOWN &&
        (nsCSSProps::IsShorthand(property) ||
         nsCSSProps::kAnimTypeTable[property] != eStyleAnimType_None)) {
      // Only need to check for longhands being animatable, as the
      // StyleAnimationValue::ComputeValues calls later on will check for
      // a shorthand's components being animatable.
      AdditionalProperty* p = properties.AppendElement();
      p->mProperty = property;
      p->mJsidIndex = i;
    }
  }

  // Sort the entries by IDL name and then get each value and
  // convert it either to a DOMString or to a
  // (DOMString or sequence<DOMString>), depending on aAllowLists,
  // and build up aResult.
  properties.Sort(AdditionalProperty::PropertyComparator());

  for (AdditionalProperty& p : properties) {
    JS::Rooted<JS::Value> value(aCx);
    if (!JS_GetPropertyById(aCx, aObject, ids[p.mJsidIndex], &value)) {
      return false;
    }
    PropertyValuesPair* pair = aResult.AppendElement();
    pair->mProperty = p.mProperty;
    if (!AppendStringOrStringSequenceToArray(aCx, value, aAllowLists,
                                             pair->mValues)) {
      return false;
    }
  }

  return true;
}

/**
 * Converts a JS object wrapped by the given JS::ForIfIterator to an
 * IDL sequence<Keyframe> and stores the resulting OffsetIndexedKeyframe
 * objects in aResult.
 */
static bool
ConvertKeyframeSequence(JSContext* aCx,
                        JS::ForOfIterator& aIterator,
                        nsTArray<OffsetIndexedKeyframe>& aResult)
{
  JS::Rooted<JS::Value> value(aCx);
  for (;;) {
    bool done;
    if (!aIterator.next(&value, &done)) {
      return false;
    }
    if (done) {
      break;
    }
    // Each value found when iterating the object must be an object
    // or null/undefined (which gets treated as a default {} dictionary
    // value).
    if (!value.isObject() && !value.isNullOrUndefined()) {
      ThrowErrorMessage(aCx, MSG_NOT_OBJECT,
                        "Element of sequence<Keyframes> argument");
      return false;
    }
    // Convert the JS value into a Keyframe dictionary value.
    OffsetIndexedKeyframe* keyframe = aResult.AppendElement();
    if (!keyframe->mKeyframeDict.Init(
          aCx, value, "Element of sequence<Keyframes> argument")) {
      return false;
    }
    // Look for additional property-values pairs on the object.
    if (value.isObject()) {
      JS::Rooted<JSObject*> object(aCx, &value.toObject());
      if (!GetPropertyValuesPairs(aCx, object,
                                  ListAllowance::eDisallow,
                                  keyframe->mPropertyValuePairs)) {
        return false;
      }
    }
  }
  return true;
}

/**
 * Checks that the given keyframes are loosely ordered (each keyframe's
 * offset that is not null is greater than or equal to the previous
 * non-null offset) and that all values are within the range [0.0, 1.0].
 *
 * @return true if the keyframes' offsets are correctly ordered and
 *   within range; false otherwise.
 */
static bool
HasValidOffsets(const nsTArray<OffsetIndexedKeyframe>& aKeyframes)
{
  double offset = 0.0;
  for (const OffsetIndexedKeyframe& keyframe : aKeyframes) {
    if (!keyframe.mKeyframeDict.mOffset.IsNull()) {
      double thisOffset = keyframe.mKeyframeDict.mOffset.Value();
      if (thisOffset < offset || thisOffset > 1.0f) {
        return false;
      }
      offset = thisOffset;
    }
  }
  return true;
}

/**
 * Fills in any null offsets for the given keyframes by applying the
 * "distribute" spacing algorithm.
 *
 * http://w3c.github.io/web-animations/#distribute-keyframe-spacing-mode
 */
static void
ApplyDistributeSpacing(nsTArray<OffsetIndexedKeyframe>& aKeyframes)
{
  // If the first or last keyframes have an unspecified offset,
  // fill them in with 0% and 100%.  If there is only a single keyframe,
  // then it gets 100%.
  if (aKeyframes.LastElement().mKeyframeDict.mOffset.IsNull()) {
    aKeyframes.LastElement().mKeyframeDict.mOffset.SetValue(1.0);
  }
  if (aKeyframes[0].mKeyframeDict.mOffset.IsNull()) {
    aKeyframes[0].mKeyframeDict.mOffset.SetValue(0.0);
  }

  // Fill in remaining missing offsets.
  size_t i = 0;
  while (i < aKeyframes.Length() - 1) {
    MOZ_ASSERT(!aKeyframes[i].mKeyframeDict.mOffset.IsNull());
    double start = aKeyframes[i].mKeyframeDict.mOffset.Value();
    size_t j = i + 1;
    while (aKeyframes[j].mKeyframeDict.mOffset.IsNull()) {
      ++j;
    }
    double end = aKeyframes[j].mKeyframeDict.mOffset.Value();
    size_t n = j - i;
    for (size_t k = 1; k < n; ++k) {
      double offset = start + double(k) / n * (end - start);
      aKeyframes[i + k].mKeyframeDict.mOffset.SetValue(offset);
    }
    i = j;
  }
}

/**
 * Splits out each property's keyframe animation segment information
 * from the OffsetIndexedKeyframe objects into an array of KeyframeValueEntry.
 *
 * The easing string value in OffsetIndexedKeyframe objects is parsed
 * into a ComputedTimingFunction value in the corresponding KeyframeValueEntry
 * objects.
 *
 * @param aTarget The target of the animation.
 * @param aPseudoType The pseudo type of the target if it is a pseudo element.
 * @param aKeyframes The keyframes to read.
 * @param aResult The array to append the resulting KeyframeValueEntry
 *   objects to.
 */
static void
GenerateValueEntries(Element* aTarget,
                     CSSPseudoElementType aPseudoType,
                     nsTArray<OffsetIndexedKeyframe>& aKeyframes,
                     nsTArray<KeyframeValueEntry>& aResult,
                     ErrorResult& aRv)
{
  nsCSSPropertySet properties;              // All properties encountered.
  nsCSSPropertySet propertiesWithFromValue; // Those with a defined 0% value.
  nsCSSPropertySet propertiesWithToValue;   // Those with a defined 100% value.

  for (OffsetIndexedKeyframe& keyframe : aKeyframes) {
    float offset = float(keyframe.mKeyframeDict.mOffset.Value());
    Maybe<ComputedTimingFunction> easing =
      AnimationUtils::ParseEasing(keyframe.mKeyframeDict.mEasing,
                                  aTarget->OwnerDoc());
    // We ignore keyframe.mKeyframeDict.mComposite since we don't support
    // composite modes on keyframes yet.

    // keyframe.mPropertyValuePairs is currently sorted by CSS property IDL
    // name, since that was the order we read the properties from the JS
    // object.  Re-sort the list so that longhand properties appear before
    // shorthands, and with shorthands all appearing in increasing order of
    // number of components.  For two longhand properties, or two shorthands
    // with the same number of components, sort by IDL name.
    //
    // Example orderings that result from this:
    //
    //   margin-left, margin
    //
    // and:
    //
    //   border-top-color, border-color, border-top, border
    //
    // This allows us to prioritize values specified by longhands (or smaller
    // shorthand subsets) when longhands and shorthands are both specified
    // on the one keyframe.
    keyframe.mPropertyValuePairs.Sort(
        PropertyValuesPair::PropertyPriorityComparator());

    nsCSSPropertySet propertiesOnThisKeyframe;
    for (const PropertyValuesPair& pair : keyframe.mPropertyValuePairs) {
      MOZ_ASSERT(pair.mValues.Length() == 1,
                 "ConvertKeyframeSequence should have parsed single "
                 "DOMString values from the property-values pairs");
      // Parse the property's string value and produce a KeyframeValueEntry (or
      // more than one, for shorthands) for it.
      nsTArray<PropertyStyleAnimationValuePair> values;
      if (StyleAnimationValue::ComputeValues(pair.mProperty,
                                             nsCSSProps::eEnabledForAllContent,
                                             aTarget,
                                             aPseudoType,
                                             pair.mValues[0],
                                             /* aUseSVGMode */ false,
                                             values)) {
        for (auto& value : values) {
          // If we already got a value for this property on the keyframe,
          // skip this one.
          if (propertiesOnThisKeyframe.HasProperty(value.mProperty)) {
            continue;
          }

          KeyframeValueEntry* entry = aResult.AppendElement();
          entry->mOffset = offset;
          entry->mProperty = value.mProperty;
          entry->mValue = value.mValue;
          entry->mTimingFunction = easing;

          if (offset == 0.0) {
            propertiesWithFromValue.AddProperty(value.mProperty);
          } else if (offset == 1.0) {
            propertiesWithToValue.AddProperty(value.mProperty);
          }
          propertiesOnThisKeyframe.AddProperty(value.mProperty);
          properties.AddProperty(value.mProperty);
        }
      }
    }
  }

  // We don't support additive segments and so can't support missing properties
  // using their underlying value in 0% and 100% keyframes.  Throw an exception
  // until we do support this.
  if (!propertiesWithFromValue.Equals(properties) ||
      !propertiesWithToValue.Equals(properties)) {
    aRv.Throw(NS_ERROR_DOM_ANIM_MISSING_PROPS_ERR);
    return;
  }
}

/**
 * Builds an array of AnimationProperty objects to represent the keyframe
 * animation segments in aEntries.
 */
static void
BuildSegmentsFromValueEntries(nsTArray<KeyframeValueEntry>& aEntries,
                              nsTArray<AnimationProperty>& aResult)
{
  if (aEntries.IsEmpty()) {
    return;
  }

  // Sort the KeyframeValueEntry objects so that all entries for a given
  // property are together, and the entries are sorted by offset otherwise.
  std::stable_sort(aEntries.begin(), aEntries.end(),
                   &KeyframeValueEntry::PropertyOffsetComparator::LessThan);

  MOZ_ASSERT(aEntries[0].mOffset == 0.0f);
  MOZ_ASSERT(aEntries.LastElement().mOffset == 1.0f);

  // For a given index i, we want to generate a segment from aEntries[i]
  // to aEntries[j], if:
  //
  //   * j > i,
  //   * aEntries[i + 1]'s offset/property is different from aEntries[i]'s, and
  //   * aEntries[j - 1]'s offset/property is different from aEntries[j]'s.
  //
  // That will eliminate runs of same offset/property values where there's no
  // point generating zero length segments in the middle of the animation.
  //
  // Additionally we need to generate a zero length segment at offset 0 and at
  // offset 1, if we have multiple values for a given property at that offset,
  // since we need to retain the very first and very last value so they can
  // be used for reverse and forward filling.

  nsCSSProperty lastProperty = eCSSProperty_UNKNOWN;
  AnimationProperty* animationProperty = nullptr;

  size_t i = 0, n = aEntries.Length();

  while (i + 1 < n) {
    // Starting from i, determine the next [i, j] interval from which to
    // generate a segment.
    size_t j;
    if (aEntries[i].mOffset == 0.0f && aEntries[i + 1].mOffset == 0.0f) {
      // We need to generate an initial zero-length segment.
      MOZ_ASSERT(aEntries[i].mProperty == aEntries[i + 1].mProperty);
      j = i + 1;
      while (aEntries[j + 1].mOffset == 0.0f) {
        MOZ_ASSERT(aEntries[j].mProperty == aEntries[j + 1].mProperty);
        ++j;
      }
    } else if (aEntries[i].mOffset == 1.0f) {
      if (aEntries[i + 1].mOffset == 1.0f) {
        // We need to generate a final zero-length segment.
        MOZ_ASSERT(aEntries[i].mProperty == aEntries[i].mProperty);
        j = i + 1;
        while (j + 1 < n && aEntries[j + 1].mOffset == 1.0f) {
          MOZ_ASSERT(aEntries[j].mProperty == aEntries[j + 1].mProperty);
          ++j;
        }
      } else {
        // New property.
        MOZ_ASSERT(aEntries[i + 1].mOffset == 0.0f);
        MOZ_ASSERT(aEntries[i].mProperty != aEntries[i + 1].mProperty);
        ++i;
        continue;
      }
    } else {
      while (aEntries[i].mOffset == aEntries[i + 1].mOffset &&
             aEntries[i].mProperty == aEntries[i + 1].mProperty) {
        ++i;
      }
      j = i + 1;
    }

    // If we've moved on to a new property, create a new AnimationProperty
    // to insert segments into.
    if (aEntries[i].mProperty != lastProperty) {
      MOZ_ASSERT(aEntries[i].mOffset == 0.0f);
      animationProperty = aResult.AppendElement();
      animationProperty->mProperty = aEntries[i].mProperty;
      lastProperty = aEntries[i].mProperty;
    }

    MOZ_ASSERT(animationProperty, "animationProperty should be valid pointer.");

    // Now generate the segment.
    AnimationPropertySegment* segment =
      animationProperty->mSegments.AppendElement();
    segment->mFromKey   = aEntries[i].mOffset;
    segment->mToKey     = aEntries[j].mOffset;
    segment->mFromValue = aEntries[i].mValue;
    segment->mToValue   = aEntries[j].mValue;
    segment->mTimingFunction = aEntries[i].mTimingFunction;

    i = j;
  }
}

/**
 * Converts a JS object to an IDL sequence<Keyframe> and builds an
 * array of AnimationProperty objects for the keyframe animation
 * that it specifies.
 *
 * @param aTarget The target of the animation.
 * @param aIterator An already-initialized ForOfIterator for the JS
 *   object to iterate over as a sequence.
 * @param aResult The array into which the resulting AnimationProperty
 *   objects will be appended.
 */
static void
BuildAnimationPropertyListFromKeyframeSequence(
    JSContext* aCx,
    Element* aTarget,
    CSSPseudoElementType aPseudoType,
    JS::ForOfIterator& aIterator,
    nsTArray<AnimationProperty>& aResult,
    ErrorResult& aRv)
{
  // Convert the object in aIterator to sequence<Keyframe>, producing
  // an array of OffsetIndexedKeyframe objects.
  AutoTArray<OffsetIndexedKeyframe,4> keyframes;
  if (!ConvertKeyframeSequence(aCx, aIterator, keyframes)) {
    aRv.Throw(NS_ERROR_FAILURE);
    return;
  }

  // If the sequence<> had zero elements, we won't generate any
  // keyframes.
  if (keyframes.IsEmpty()) {
    return;
  }

  // Check that the keyframes are loosely sorted and with values all
  // between 0% and 100%.
  if (!HasValidOffsets(keyframes)) {
    aRv.ThrowTypeError<MSG_INVALID_KEYFRAME_OFFSETS>();
    return;
  }

  // Fill in 0%/100% values if the first/element keyframes don't have
  // a specified offset, and evenly space those that have a missing
  // offset.  (We don't support paced spacing yet.)
  ApplyDistributeSpacing(keyframes);

  // Convert the OffsetIndexedKeyframes into a list of KeyframeValueEntry
  // objects.
  nsTArray<KeyframeValueEntry> entries;
  GenerateValueEntries(aTarget, aPseudoType, keyframes, entries, aRv);
  if (aRv.Failed()) {
    return;
  }

  // Finally, build an array of AnimationProperty objects in aResult
  // corresponding to the entries.
  BuildSegmentsFromValueEntries(entries, aResult);
}

/**
 * Converts a JS object to an IDL PropertyIndexedKeyframes and builds an
 * array of AnimationProperty objects for the keyframe animation
 * that it specifies.
 *
 * @param aTarget The target of the animation.
 * @param aValue The JS object.
 * @param aResult The array into which the resulting AnimationProperty
 *   objects will be appended.
 */
static void
BuildAnimationPropertyListFromPropertyIndexedKeyframes(
    JSContext* aCx,
    Element* aTarget,
    CSSPseudoElementType aPseudoType,
    JS::Handle<JS::Value> aValue,
    InfallibleTArray<AnimationProperty>& aResult,
    ErrorResult& aRv)
{
  MOZ_ASSERT(aValue.isObject());

  // Convert the object to a PropertyIndexedKeyframes dictionary to
  // get its explicit dictionary members.
  binding_detail::FastPropertyIndexedKeyframes keyframes;
  if (!keyframes.Init(aCx, aValue, "PropertyIndexedKeyframes argument",
                      false)) {
    aRv.Throw(NS_ERROR_FAILURE);
    return;
  }

  Maybe<ComputedTimingFunction> easing =
    AnimationUtils::ParseEasing(keyframes.mEasing, aTarget->OwnerDoc());

  // We ignore easing.mComposite since we don't support composite modes on
  // keyframes yet.

  // Get all the property--value-list pairs off the object.
  JS::Rooted<JSObject*> object(aCx, &aValue.toObject());
  nsTArray<PropertyValuesPair> propertyValuesPairs;
  if (!GetPropertyValuesPairs(aCx, object, ListAllowance::eAllow,
                              propertyValuesPairs)) {
    aRv.Throw(NS_ERROR_FAILURE);
    return;
  }

  // We must keep track of which properties we've already generated
  // an AnimationProperty since the author could have specified both a
  // shorthand and one of its component longhands on the
  // PropertyIndexedKeyframes.
  nsCSSPropertySet properties;

  // Create AnimationProperty objects for each PropertyValuesPair, applying
  // the "distribute" spacing algorithm to the segments.
  for (const PropertyValuesPair& pair : propertyValuesPairs) {
    size_t count = pair.mValues.Length();
    if (count == 0) {
      // No animation values for this property.
      continue;
    }
    if (count == 1) {
      // We don't support additive segments and so can't support an
      // animation that goes from the underlying value to this
      // specified value.  Throw an exception until we do support this.
      aRv.Throw(NS_ERROR_DOM_ANIM_MISSING_PROPS_ERR);
      return;
    }

    // If we find an invalid value, we don't create a segment for it, but
    // we adjust the surrounding segments so that the timing of the segments
    // is the same as if we did support it.  For example, animating with
    // values ["red", "green", "yellow", "invalid", "blue"] will generate
    // segments with this timing:
    //
    //   0.00 -> 0.25 : red -> green
    //   0.25 -> 0.50 : green -> yellow
    //   0.50 -> 1.00 : yellow -> blue
    //
    // With future spec clarifications we might decide to preserve the invalid
    // value on the segment and make the animation code deal with the invalid
    // value instead.
    nsTArray<PropertyStyleAnimationValuePair> fromValues;
    float fromKey = 0.0f;
    if (!StyleAnimationValue::ComputeValues(pair.mProperty,
                                            nsCSSProps::eEnabledForAllContent,
                                            aTarget,
                                            aPseudoType,
                                            pair.mValues[0],
                                            /* aUseSVGMode */ false,
                                            fromValues)) {
      // We need to throw for an invalid first value, since that would imply an
      // additive animation, which we don't support yet.
      aRv.Throw(NS_ERROR_DOM_ANIM_MISSING_PROPS_ERR);
      return;
    }

    if (fromValues.IsEmpty()) {
      // All longhand components of a shorthand pair.mProperty must be disabled.
      continue;
    }

    // Create AnimationProperty objects for each property that had a
    // value computed.  When pair.mProperty is a longhand, it is just
    // that property.  When pair.mProperty is a shorthand, we'll have
    // one property per longhand component.
    nsTArray<size_t> animationPropertyIndexes;
    animationPropertyIndexes.SetLength(fromValues.Length());
    for (size_t i = 0, n = fromValues.Length(); i < n; ++i) {
      nsCSSProperty p = fromValues[i].mProperty;
      bool found = false;
      if (properties.HasProperty(p)) {
        // We have already dealt with this property.  Look up and
        // overwrite the old AnimationProperty object.
        for (size_t j = 0, m = aResult.Length(); j < m; ++j) {
          if (aResult[j].mProperty == p) {
            aResult[j].mSegments.Clear();
            animationPropertyIndexes[i] = j;
            found = true;
            break;
          }
        }
        MOZ_ASSERT(found, "properties is inconsistent with aResult");
      }
      if (!found) {
        // This is the first time we've encountered this property.
        animationPropertyIndexes[i] = aResult.Length();
        AnimationProperty* animationProperty = aResult.AppendElement();
        animationProperty->mProperty = p;
        properties.AddProperty(p);
      }
    }

    double portion = 1.0 / (count - 1);
    for (size_t i = 0; i < count - 1; ++i) {
      nsTArray<PropertyStyleAnimationValuePair> toValues;
      float toKey = (i + 1) * portion;
      if (!StyleAnimationValue::ComputeValues(pair.mProperty,
                                              nsCSSProps::eEnabledForAllContent,
                                              aTarget,
                                              aPseudoType,
                                              pair.mValues[i + 1],
                                              /* aUseSVGMode */ false,
                                              toValues)) {
        if (i + 1 == count - 1) {
          // We need to throw for an invalid last value, since that would
          // imply an additive animation, which we don't support yet.
          aRv.Throw(NS_ERROR_DOM_ANIM_MISSING_PROPS_ERR);
          return;
        }
        // Otherwise, skip the segment.
        continue;
      }
      MOZ_ASSERT(toValues.Length() == fromValues.Length(),
                 "should get the same number of properties as the last time "
                 "we called ComputeValues for pair.mProperty");
      for (size_t j = 0, n = toValues.Length(); j < n; ++j) {
        size_t index = animationPropertyIndexes[j];
        AnimationPropertySegment* segment =
          aResult[index].mSegments.AppendElement();
        segment->mFromKey = fromKey;
        segment->mFromValue = fromValues[j].mValue;
        segment->mToKey = toKey;
        segment->mToValue = toValues[j].mValue;
        segment->mTimingFunction = easing;
      }
      fromValues = Move(toValues);
      fromKey = toKey;
    }
  }
}

/**
 * Converts a JS value to an IDL
 * (PropertyIndexedKeyframes or sequence<Keyframe>) value and builds an
 * array of AnimationProperty objects for the keyframe animation
 * that it specifies.
 *
 * @param aTarget The target of the animation, used to resolve style
 *   for a property's underlying value if needed.
 * @param aFrames The JS value, provided as an optional IDL |object?| value,
 *   that is the keyframe list specification.
 * @param aResult The array into which the resulting AnimationProperty
 *   objects will be appended.
 */
/* static */ void
KeyframeEffectReadOnly::BuildAnimationPropertyList(
    JSContext* aCx,
    Element* aTarget,
    CSSPseudoElementType aPseudoType,
    JS::Handle<JSObject*> aFrames,
    InfallibleTArray<AnimationProperty>& aResult,
    ErrorResult& aRv)
{
  MOZ_ASSERT(aResult.IsEmpty());

  // A frame list specification in the IDL is:
  //
  // (PropertyIndexedKeyframes or sequence<Keyframe> or SharedKeyframeList)
  //
  // We don't support SharedKeyframeList yet, but we do the other two.  We
  // manually implement the parts of JS-to-IDL union conversion algorithm
  // from the Web IDL spec, since we have to represent this an object? so
  // we can look at the open-ended set of properties on a
  // PropertyIndexedKeyframes or Keyframe.

  if (!aFrames) {
    // The argument was explicitly null.  In this case, the default dictionary
    // value for PropertyIndexedKeyframes would result in no keyframes.
    return;
  }

  // At this point we know we have an object.  We try to convert it to a
  // sequence<Keyframe> first, and if that fails due to not being iterable,
  // we try to convert it to PropertyIndexedKeyframes.
  JS::Rooted<JS::Value> objectValue(aCx, JS::ObjectValue(*aFrames));
  JS::ForOfIterator iter(aCx);
  if (!iter.init(objectValue, JS::ForOfIterator::AllowNonIterable)) {
    aRv.Throw(NS_ERROR_FAILURE);
    return;
  }

  if (iter.valueIsIterable()) {
    BuildAnimationPropertyListFromKeyframeSequence(aCx, aTarget, aPseudoType,
                                                   iter, aResult, aRv);
  } else {
    BuildAnimationPropertyListFromPropertyIndexedKeyframes(aCx, aTarget,
                                                           aPseudoType,
                                                           objectValue, aResult,
                                                           aRv);
  }
}

/* static */ already_AddRefed<KeyframeEffectReadOnly>
KeyframeEffectReadOnly::Constructor(
    const GlobalObject& aGlobal,
    const Nullable<ElementOrCSSPseudoElement>& aTarget,
    JS::Handle<JSObject*> aFrames,
    const UnrestrictedDoubleOrKeyframeEffectOptions& aOptions,
    ErrorResult& aRv)
{
  return ConstructKeyframeEffect<KeyframeEffectReadOnly>(aGlobal, aTarget,
                                                         aFrames, aOptions,
                                                         aRv);
}

void
KeyframeEffectReadOnly::GetTarget(
    Nullable<OwningElementOrCSSPseudoElement>& aRv) const
{
  if (!mTarget) {
    aRv.SetNull();
    return;
  }

  switch (mPseudoType) {
    case CSSPseudoElementType::before:
    case CSSPseudoElementType::after:
      aRv.SetValue().SetAsCSSPseudoElement() =
        CSSPseudoElement::GetCSSPseudoElement(mTarget, mPseudoType);
      break;

    case CSSPseudoElementType::NotPseudo:
      aRv.SetValue().SetAsElement() = mTarget;
      break;

    default:
      NS_NOTREACHED("Animation of unsupported pseudo-type");
      aRv.SetNull();
  }
}

void
KeyframeEffectReadOnly::GetFrames(JSContext*& aCx,
                                  nsTArray<JSObject*>& aResult,
                                  ErrorResult& aRv)
{
  nsTArray<OrderedKeyframeValueEntry> entries;

  for (const AnimationProperty& property : mProperties) {
    for (size_t i = 0, n = property.mSegments.Length(); i < n; i++) {
      const AnimationPropertySegment& segment = property.mSegments[i];

      // We append the mFromValue for each segment.  If the mToValue
      // differs from the following segment's mFromValue, or if we're on
      // the last segment, then we append the mToValue as well.
      //
      // Each value is annotated with whether it is a "first", "left", "right",
      // or "last" value.  "left" and "right" values represent the value coming
      // in to and out of a given offset, in the middle of an animation.  For
      // most segments, the mToValue is the "left" and the following segment's
      // mFromValue is the "right".  The "first" and "last" values are the
      // additional values assigned to offset 0 or 1 for reverse and forward
      // filling.  These annotations are used to ensure multiple values for a
      // given property are sorted correctly and that we do not merge Keyframes
      // with different values for the same offset.

      OrderedKeyframeValueEntry* entry = entries.AppendElement();
      entry->mProperty = property.mProperty;
      entry->mValue = segment.mFromValue;
      entry->mOffset = segment.mFromKey;
      entry->mTimingFunction = &segment.mTimingFunction;
      entry->mPosition =
        segment.mFromKey == segment.mToKey && segment.mFromKey == 0.0f ?
          ValuePosition::First :
          ValuePosition::Right;

      if (i == n - 1 ||
          segment.mToValue != property.mSegments[i + 1].mFromValue) {
        entry = entries.AppendElement();
        entry->mProperty = property.mProperty;
        entry->mValue = segment.mToValue;
        entry->mOffset = segment.mToKey;
        entry->mTimingFunction = segment.mToKey == 1.0f ?
          nullptr : &segment.mTimingFunction;
        entry->mPosition =
          segment.mFromKey == segment.mToKey && segment.mToKey == 1.0f ?
            ValuePosition::Last :
            ValuePosition::Left;
      }
    }
  }

  entries.Sort(OrderedKeyframeValueEntry::ForKeyframeGenerationComparator());

  for (size_t i = 0, n = entries.Length(); i < n; ) {
    OrderedKeyframeValueEntry* entry = &entries[i];
    OrderedKeyframeValueEntry* previousEntry = nullptr;

    // Create a JS object with the explicit ComputedKeyframe dictionary members.
    ComputedKeyframe keyframeDict;
    keyframeDict.mOffset.SetValue(entry->mOffset);
    keyframeDict.mComputedOffset.Construct(entry->mOffset);
    if (entry->mTimingFunction && entry->mTimingFunction->isSome()) {
      // If null, leave easing as its default "linear".
      keyframeDict.mEasing.Truncate();
      entry->mTimingFunction->value().AppendToString(keyframeDict.mEasing);
    }
    keyframeDict.mComposite.SetValue(CompositeOperation::Replace);

    JS::Rooted<JS::Value> keyframeJSValue(aCx);
    if (!ToJSValue(aCx, keyframeDict, &keyframeJSValue)) {
      aRv.Throw(NS_ERROR_FAILURE);
      return;
    }

    JS::Rooted<JSObject*> keyframe(aCx, &keyframeJSValue.toObject());
    do {
      const char* name = nsCSSProps::PropertyIDLName(entry->mProperty);
      nsString stringValue;
      StyleAnimationValue::UncomputeValue(entry->mProperty,
                                          entry->mValue,
                                          stringValue);
      JS::Rooted<JS::Value> value(aCx);
      if (!ToJSValue(aCx, stringValue, &value) ||
          !JS_DefineProperty(aCx, keyframe, name, value, JSPROP_ENUMERATE)) {
        aRv.Throw(NS_ERROR_FAILURE);
        return;
      }
      if (++i == n) {
        break;
      }
      previousEntry = entry;
      entry = &entries[i];
    } while (entry->SameKeyframe(*previousEntry));

    aResult.AppendElement(keyframe);
  }
}


void
KeyframeEffectReadOnly::GetPropertyState(
    nsTArray<AnimationPropertyState>& aStates) const
{
  for (const AnimationProperty& property : mProperties) {
    // Bug 1252730: We should also expose this winsInCascade as well.
    if (!property.mWinsInCascade) {
      continue;
    }

    AnimationPropertyState state;
    state.mProperty.Construct(
      NS_ConvertASCIItoUTF16(nsCSSProps::GetStringValue(property.mProperty)));
    state.mRunningOnCompositor.Construct(property.mIsRunningOnCompositor);

    nsXPIDLString localizedString;
    if (property.mPerformanceWarning &&
        property.mPerformanceWarning->ToLocalizedString(localizedString)) {
      state.mWarning.Construct(localizedString);
    }

    aStates.AppendElement(state);
  }
}

/* static */ const TimeDuration
KeyframeEffectReadOnly::OverflowRegionRefreshInterval()
{
  // The amount of time we can wait between updating throttled animations
  // on the main thread that influence the overflow region.
  static const TimeDuration kOverflowRegionRefreshInterval =
    TimeDuration::FromMilliseconds(200);

  return kOverflowRegionRefreshInterval;
}

bool
KeyframeEffectReadOnly::CanThrottle() const
{
  // Unthrottle if we are not in effect or current. This will be the case when
  // our owning animation has finished, is idle, or when we are in the delay
  // phase (but without a backwards fill). In each case the computed progress
  // value produced on each tick will be the same so we will skip requesting
  // unnecessary restyles in NotifyAnimationTimingUpdated. Any calls we *do* get
  // here will be because of a change in state (e.g. we are newly finished or
  // newly no longer in effect) in which case we shouldn't throttle the sample.
  if (!IsInEffect() || !IsCurrent()) {
    return false;
  }

  nsIFrame* frame = GetAnimationFrame();
  if (!frame) {
    // There are two possible cases here.
    // a) No target element
    // b) The target element has no frame, e.g. because it is in a display:none
    //    subtree.
    // In either case we can throttle the animation because there is no
    // need to update on the main thread.
    return true;
  }

  // First we need to check layer generation and transform overflow
  // prior to the property.mIsRunningOnCompositor check because we should
  // occasionally unthrottle these animations even if the animations are
  // already running on compositor.
  for (const LayerAnimationInfo::Record& record :
        LayerAnimationInfo::sRecords) {
    // Skip properties that are overridden in the cascade.
    // (GetAnimationOfProperty, as called by HasAnimationOfProperty,
    // only returns an animation if it currently wins in the cascade.)
    if (!HasAnimationOfProperty(record.mProperty)) {
      continue;
    }

    EffectSet* effectSet = EffectSet::GetEffectSet(mTarget, mPseudoType);
    MOZ_ASSERT(effectSet, "CanThrottle should be called on an effect "
                          "associated with a target element");
    layers::Layer* layer =
      FrameLayerBuilder::GetDedicatedLayer(frame, record.mLayerType);
    // Unthrottle if the layer needs to be brought up to date
    if (!layer ||
        effectSet->GetAnimationGeneration() !=
          layer->GetAnimationGeneration()) {
      return false;
    }

    // If this is a transform animation that affects the overflow region,
    // we should unthrottle the animation periodically.
    if (record.mProperty == eCSSProperty_transform &&
        !CanThrottleTransformChanges(*frame)) {
      return false;
    }
  }

  for (const AnimationProperty& property : mProperties) {
    if (!property.mIsRunningOnCompositor) {
      return false;
    }
  }

  return true;
}

bool
KeyframeEffectReadOnly::CanThrottleTransformChanges(nsIFrame& aFrame) const
{
  // If we know that the animation cannot cause overflow,
  // we can just disable flushes for this animation.

  // If we don't show scrollbars, we don't care about overflow.
  if (LookAndFeel::GetInt(LookAndFeel::eIntID_ShowHideScrollbars) == 0) {
    return true;
  }

  nsPresContext* presContext = GetPresContext();
  // CanThrottleTransformChanges is only called as part of a refresh driver tick
  // in which case we expect to has a pres context.
  MOZ_ASSERT(presContext);

  TimeStamp now =
    presContext->RefreshDriver()->MostRecentRefresh();

  EffectSet* effectSet = EffectSet::GetEffectSet(mTarget, mPseudoType);
  MOZ_ASSERT(effectSet, "CanThrottleTransformChanges is expected to be called"
                        " on an effect in an effect set");
  MOZ_ASSERT(mAnimation, "CanThrottleTransformChanges is expected to be called"
                         " on an effect with a parent animation");
  TimeStamp animationRuleRefreshTime =
    effectSet->AnimationRuleRefreshTime(mAnimation->CascadeLevel());
  // If this animation can cause overflow, we can throttle some of the ticks.
  if (!animationRuleRefreshTime.IsNull() &&
      (now - animationRuleRefreshTime) < OverflowRegionRefreshInterval()) {
    return true;
  }

  // If the nearest scrollable ancestor has overflow:hidden,
  // we don't care about overflow.
  nsIScrollableFrame* scrollable =
    nsLayoutUtils::GetNearestScrollableFrame(&aFrame);
  if (!scrollable) {
    return true;
  }

  ScrollbarStyles ss = scrollable->GetScrollbarStyles();
  if (ss.mVertical == NS_STYLE_OVERFLOW_HIDDEN &&
      ss.mHorizontal == NS_STYLE_OVERFLOW_HIDDEN &&
      scrollable->GetLogicalScrollPosition() == nsPoint(0, 0)) {
    return true;
  }

  return false;
}

nsIFrame*
KeyframeEffectReadOnly::GetAnimationFrame() const
{
  if (!mTarget) {
    return nullptr;
  }

  nsIFrame* frame = mTarget->GetPrimaryFrame();
  if (!frame) {
    return nullptr;
  }

  if (mPseudoType == CSSPseudoElementType::before) {
    frame = nsLayoutUtils::GetBeforeFrame(frame);
  } else if (mPseudoType == CSSPseudoElementType::after) {
    frame = nsLayoutUtils::GetAfterFrame(frame);
  } else {
    MOZ_ASSERT(mPseudoType == CSSPseudoElementType::NotPseudo,
               "unknown mPseudoType");
  }
  if (!frame) {
    return nullptr;
  }

  return nsLayoutUtils::GetStyleFrame(frame);
}

nsIDocument*
KeyframeEffectReadOnly::GetRenderedDocument() const
{
  if (!mTarget) {
    return nullptr;
  }
  return mTarget->GetComposedDoc();
}

nsPresContext*
KeyframeEffectReadOnly::GetPresContext() const
{
  nsIDocument* doc = GetRenderedDocument();
  if (!doc) {
    return nullptr;
  }
  nsIPresShell* shell = doc->GetShell();
  if (!shell) {
    return nullptr;
  }
  return shell->GetPresContext();
}

/* static */ bool
KeyframeEffectReadOnly::IsGeometricProperty(
  const nsCSSProperty aProperty)
{
  switch (aProperty) {
    case eCSSProperty_bottom:
    case eCSSProperty_height:
    case eCSSProperty_left:
    case eCSSProperty_right:
    case eCSSProperty_top:
    case eCSSProperty_width:
      return true;
    default:
      return false;
  }
}

/* static */ bool
KeyframeEffectReadOnly::CanAnimateTransformOnCompositor(
  const nsIFrame* aFrame,
  AnimationPerformanceWarning::Type& aPerformanceWarning)
{
  // Disallow OMTA for preserve-3d transform. Note that we check the style property
  // rather than Extend3DContext() since that can recurse back into this function
  // via HasOpacity(). See bug 779598.
  if (aFrame->Combines3DTransformWithAncestors() ||
      aFrame->StyleDisplay()->mTransformStyle == NS_STYLE_TRANSFORM_STYLE_PRESERVE_3D) {
    aPerformanceWarning = AnimationPerformanceWarning::Type::TransformPreserve3D;
    return false;
  }
  // Note that testing BackfaceIsHidden() is not a sufficient test for
  // what we need for animating backface-visibility correctly if we
  // remove the above test for Extend3DContext(); that would require
  // looking at backface-visibility on descendants as well. See bug 1186204.
  if (aFrame->StyleDisplay()->BackfaceIsHidden()) {
    aPerformanceWarning =
      AnimationPerformanceWarning::Type::TransformBackfaceVisibilityHidden;
    return false;
  }
  // Async 'transform' animations of aFrames with SVG transforms is not
  // supported.  See bug 779599.
  if (aFrame->IsSVGTransformed()) {
    aPerformanceWarning = AnimationPerformanceWarning::Type::TransformSVG;
    return false;
  }

  return true;
}

bool
KeyframeEffectReadOnly::ShouldBlockCompositorAnimations(
  const nsIFrame* aFrame,
  AnimationPerformanceWarning::Type& aPerformanceWarning) const
{
  // We currently only expect this method to be called when this effect
  // is attached to a playing Animation. If that ever changes we'll need
  // to update this to only return true when that is the case since paused,
  // filling, cancelled Animations etc. shouldn't stop other Animations from
  // running on the compositor.
  MOZ_ASSERT(mAnimation && mAnimation->IsPlaying());

  for (const AnimationProperty& property : mProperties) {
    // If a property is overridden in the CSS cascade, it should not block other
    // animations from running on the compositor.
    if (!property.mWinsInCascade) {
      continue;
    }
    // Check for geometric properties
    if (IsGeometricProperty(property.mProperty)) {
      aPerformanceWarning =
        AnimationPerformanceWarning::Type::WithGeometricProperties;
      return true;
    }

    // Check for unsupported transform animations
    if (property.mProperty == eCSSProperty_transform) {
      if (!CanAnimateTransformOnCompositor(aFrame,
                                           aPerformanceWarning)) {
        return true;
      }
    }
  }

  return false;
}

void
KeyframeEffectReadOnly::SetPerformanceWarning(
  nsCSSProperty aProperty,
  const AnimationPerformanceWarning& aWarning)
{
  for (AnimationProperty& property : mProperties) {
    if (property.mProperty == aProperty &&
        (!property.mPerformanceWarning ||
         *property.mPerformanceWarning != aWarning)) {
      property.mPerformanceWarning = Some(aWarning);

      nsXPIDLString localizedString;
      if (nsLayoutUtils::IsAnimationLoggingEnabled() &&
          property.mPerformanceWarning->ToLocalizedString(localizedString)) {
        nsAutoCString logMessage = NS_ConvertUTF16toUTF8(localizedString);
        AnimationUtils::LogAsyncAnimationFailure(logMessage, mTarget);
      }
      return;
    }
  }
}

//---------------------------------------------------------------------
//
// KeyframeEffect
//
//---------------------------------------------------------------------

KeyframeEffect::KeyframeEffect(nsIDocument* aDocument,
                               Element* aTarget,
                               CSSPseudoElementType aPseudoType,
                               const TimingParams& aTiming)
  : KeyframeEffectReadOnly(aDocument, aTarget, aPseudoType,
                           new AnimationEffectTiming(aTiming, this))
{
}

JSObject*
KeyframeEffect::WrapObject(JSContext* aCx,
                           JS::Handle<JSObject*> aGivenProto)
{
  return KeyframeEffectBinding::Wrap(aCx, this, aGivenProto);
}

/* static */ already_AddRefed<KeyframeEffect>
KeyframeEffect::Constructor(
    const GlobalObject& aGlobal,
    const Nullable<ElementOrCSSPseudoElement>& aTarget,
    JS::Handle<JSObject*> aFrames,
    const UnrestrictedDoubleOrKeyframeEffectOptions& aOptions,
    ErrorResult& aRv)
{
  return ConstructKeyframeEffect<KeyframeEffect>(aGlobal, aTarget, aFrames,
                                                 aOptions, aRv);
}

/* static */ already_AddRefed<KeyframeEffect>
KeyframeEffect::Constructor(
    const GlobalObject& aGlobal,
    const Nullable<ElementOrCSSPseudoElement>& aTarget,
    JS::Handle<JSObject*> aFrames,
    const TimingParams& aTiming,
    ErrorResult& aRv)
{
  return ConstructKeyframeEffect<KeyframeEffect>(aGlobal, aTarget, aFrames,
                                                 aTiming, aRv);
}

void KeyframeEffect::NotifySpecifiedTimingUpdated()
{
  nsIDocument* doc = nullptr;
  // Bug 1249219:
  // We don't support animation mutation observers on pseudo-elements yet.
  if (mTarget &&
      mPseudoType == CSSPseudoElementType::NotPseudo) {
    doc = mTarget->OwnerDoc();
  }

  nsAutoAnimationMutationBatch mb(doc);

  if (mAnimation) {
    mAnimation->NotifyEffectTimingUpdated();

    if (mAnimation->IsRelevant()) {
      nsNodeUtils::AnimationChanged(mAnimation);
    }

    nsPresContext* presContext = GetPresContext();
    if (presContext) {
      presContext->EffectCompositor()->
        RequestRestyle(mTarget, mPseudoType,
                       EffectCompositor::RestyleType::Layer,
                       mAnimation->CascadeLevel());
    }
  }
}

KeyframeEffect::~KeyframeEffect()
{
  mTiming->Unlink();
}

} // namespace dom
} // namespace mozilla