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/AnimatableBinding.h"
#include "mozilla/dom/KeyframeEffectBinding.h"
#include "mozilla/AnimationUtils.h"
#include "mozilla/EffectCompositor.h"
#include "mozilla/FloatingPoint.h"
#include "mozilla/LookAndFeel.h" // For LookAndFeel::GetInt
#include "mozilla/KeyframeUtils.h"
#include "mozilla/StyleAnimationValue.h"
#include "Layers.h" // For Layer
#include "nsComputedDOMStyle.h" // nsComputedDOMStyle::GetStyleContextForElement
#include "nsCSSPropertySet.h"
#include "nsCSSProps.h" // For nsCSSProps::PropHasFlags
#include "nsCSSPseudoElements.h" // For CSSPseudoElementType
#include "nsDOMMutationObserver.h" // For nsAutoAnimationMutationBatch
#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 ((result.mPhase == ComputedTiming::AnimationPhase::After &&
       thisIterationReverse) ||
      (result.mPhase == ComputedTiming::AnimationPhase::Before &&
       !thisIterationReverse)) {
    result.mBeforeFlag = ComputedTimingFunction::BeforeFlag::Set;
  }

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

  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();
}

static bool
KeyframesEqualIgnoringComputedOffsets(const nsTArray<Keyframe>& aLhs,
                                      const nsTArray<Keyframe>& aRhs)
{
  if (aLhs.Length() != aRhs.Length()) {
    return false;
  }

  for (size_t i = 0, len = aLhs.Length(); i < len; ++i) {
    const Keyframe& a = aLhs[i];
    const Keyframe& b = aRhs[i];
    if (a.mOffset != b.mOffset ||
        a.mTimingFunction != b.mTimingFunction ||
        a.mPropertyValues != b.mPropertyValues) {
      return false;
    }
  }
  return true;
}

void
KeyframeEffectReadOnly::SetFrames(nsTArray<Keyframe>&& aFrames,
                                  nsStyleContext* aStyleContext)
{
  if (KeyframesEqualIgnoringComputedOffsets(aFrames, mFrames)) {
    return;
  }

  mFrames = Move(aFrames);
  KeyframeUtils::ApplyDistributeSpacing(mFrames);

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

  if (aStyleContext) {
    UpdateProperties(aStyleContext);
  }
}

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;
}

void
KeyframeEffectReadOnly::UpdateProperties(nsStyleContext* aStyleContext)
{
  MOZ_ASSERT(aStyleContext);

  nsTArray<AnimationProperty> properties;
  if (mTarget) {
    properties =
      KeyframeUtils::GetAnimationPropertiesFromKeyframes(aStyleContext,
                                                         mTarget,
                                                         mPseudoType,
                                                         mFrames);
  }

  if (mProperties == properties) {
    return;
  }

  // Preserve the state of mWinsInCascade and mIsRunningOnCompositor flags.
  nsCSSPropertySet winningInCascadeProperties;
  nsCSSPropertySet runningOnCompositorProperties;

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

  mProperties = Move(properties);

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

  if (mTarget) {
    EffectSet* effectSet = EffectSet::GetEffectSet(mTarget, mPseudoType);
    if (effectSet) {
      effectSet->MarkCascadeNeedsUpdate();
    }
  }

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

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();
    }

    // Special handling for zero-length segments
    if (segment->mToKey == segment->mFromKey) {
      if (computedTiming.mProgress.Value() < 0) {
        aStyleRule->AddValue(prop.mProperty, segment->mFromValue);
      } else {
        aStyleRule->AddValue(prop.mProperty, segment->mToValue);
      }
      continue;
    }

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

    StyleAnimationValue val;
    if (StyleAnimationValue::Interpolate(prop.mProperty,
                                         segment->mFromValue,
                                         segment->mToValue,
                                         valuePosition, val)) {
      aStyleRule->AddValue(prop.mProperty, Move(val));
    } else if (valuePosition < 0.5) {
      aStyleRule->AddValue(prop.mProperty, segment->mFromValue);
    } else {
      aStyleRule->AddValue(prop.mProperty, segment->mToValue);
    }
  }
}

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;
  }

  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;
  }

  nsTArray<Keyframe> keyframes =
    KeyframeUtils::GetKeyframesFromObject(aGlobal.Context(), aFrames, aRv);
  if (aRv.Failed()) {
    return nullptr;
  }

  RefPtr<KeyframeEffectType> effect =
    new KeyframeEffectType(targetElement->OwnerDoc(), targetElement,
                           pseudoType, timingParams);

  RefPtr<nsStyleContext> styleContext;
  nsIPresShell* shell = doc->GetShell();
  if (shell && targetElement) {
    nsIAtom* pseudo =
      pseudoType < CSSPseudoElementType::Count ?
      nsCSSPseudoElements::GetPseudoAtom(pseudoType) : nullptr;
    styleContext =
      nsComputedDOMStyle::GetStyleContextForElement(targetElement, pseudo,
                                                    shell);
  }
  effect->SetFrames(Move(keyframes), styleContext);

  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);
    }
  };
};

/* 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();
  }
}

static void
CreatePropertyValue(nsCSSProperty aProperty,
                    float aOffset,
                    const Maybe<ComputedTimingFunction>& aTimingFunction,
                    const StyleAnimationValue& aValue,
                    AnimationPropertyValueDetails& aResult)
{
  aResult.mOffset = aOffset;

  nsString stringValue;
  StyleAnimationValue::UncomputeValue(aProperty, aValue, stringValue);
  aResult.mValue = stringValue;

  if (aTimingFunction) {
    aResult.mEasing.Construct();
    aTimingFunction->AppendToString(aResult.mEasing.Value());
  } else {
    aResult.mEasing.Construct(NS_LITERAL_STRING("linear"));
  }

  aResult.mComposite = CompositeOperation::Replace;
}

void
KeyframeEffectReadOnly::GetProperties(
    nsTArray<AnimationPropertyDetails>& aProperties,
    ErrorResult& aRv) const
{
  for (const AnimationProperty& property : mProperties) {
    AnimationPropertyDetails propertyDetails;
    propertyDetails.mProperty =
      NS_ConvertASCIItoUTF16(nsCSSProps::GetStringValue(property.mProperty));
    propertyDetails.mRunningOnCompositor = property.mIsRunningOnCompositor;

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

    if (!propertyDetails.mValues.SetCapacity(property.mSegments.Length(),
                                             mozilla::fallible)) {
      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
      return;
    }

    for (size_t segmentIdx = 0, segmentLen = property.mSegments.Length();
         segmentIdx < segmentLen;
         segmentIdx++)
    {
      const AnimationPropertySegment& segment = property.mSegments[segmentIdx];

      binding_detail::FastAnimationPropertyValueDetails fromValue;
      CreatePropertyValue(property.mProperty, segment.mFromKey,
                          segment.mTimingFunction, segment.mFromValue,
                          fromValue);
      // We don't apply timing functions for zero-length segments, so
      // don't return one here.
      if (segment.mFromKey == segment.mToKey) {
        fromValue.mEasing.Reset();
      }
      // The following won't fail since we have already allocated the capacity
      // above.
      propertyDetails.mValues.AppendElement(fromValue, mozilla::fallible);

      // Normally we can ignore the to-value for this segment since it is
      // identical to the from-value from the next segment. However, we need
      // to add it if either:
      // a) this is the last segment, or
      // b) the next segment's from-value differs.
      if (segmentIdx == segmentLen - 1 ||
          property.mSegments[segmentIdx + 1].mFromValue != segment.mToValue) {
        binding_detail::FastAnimationPropertyValueDetails toValue;
        CreatePropertyValue(property.mProperty, segment.mToKey,
                            Nothing(), segment.mToValue, toValue);
        // It doesn't really make sense to have a timing function on the
        // last property value or before a sudden jump so we just drop the
        // easing property altogether.
        toValue.mEasing.Reset();
        propertyDetails.mValues.AppendElement(toValue, mozilla::fallible);
      }
    }

    aProperties.AppendElement(propertyDetails);
  }
}

// TODO: This will eventually become the new GetFrames
static void
GetFramesFromFrames(JSContext*& aCx,
                    const nsTArray<Keyframe>& aFrames,
                    nsTArray<JSObject*>& aResult,
                    ErrorResult& aRv)
{
  MOZ_ASSERT(aResult.IsEmpty());
  MOZ_ASSERT(!aRv.Failed());

  if (!aResult.SetCapacity(aFrames.Length(), mozilla::fallible)) {
    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
    return;
  }

  for (const Keyframe& keyframe : aFrames) {
    // Set up a dictionary object for the explicit members
    BaseComputedKeyframe keyframeDict;
    if (keyframe.mOffset) {
      keyframeDict.mOffset.SetValue(keyframe.mOffset.value());
    }
    keyframeDict.mComputedOffset.Construct(keyframe.mComputedOffset);
    if (keyframe.mTimingFunction) {
      keyframeDict.mEasing.Truncate();
      keyframe.mTimingFunction.ref().AppendToString(keyframeDict.mEasing);
    } // else if null, leave easing as its default "linear".

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

    JS::Rooted<JSObject*> keyframeObject(aCx, &keyframeJSValue.toObject());
    for (const PropertyValuePair& propertyValue : keyframe.mPropertyValues) {

      const char* name = nsCSSProps::PropertyIDLName(propertyValue.mProperty);

      // nsCSSValue::AppendToString does not accept shorthands properties but
      // works with token stream values if we pass eCSSProperty_UNKNOWN as
      // the property.
      nsCSSProperty propertyForSerializing =
        nsCSSProps::IsShorthand(propertyValue.mProperty)
        ? eCSSProperty_UNKNOWN
        : propertyValue.mProperty;

      nsAutoString stringValue;
      propertyValue.mValue.AppendToString(
        propertyForSerializing, stringValue, nsCSSValue::eNormalized);

      JS::Rooted<JS::Value> value(aCx);
      if (!ToJSValue(aCx, stringValue, &value) ||
          !JS_DefineProperty(aCx, keyframeObject, name, value,
                             JSPROP_ENUMERATE)) {
        aRv.Throw(NS_ERROR_FAILURE);
        return;
      }
    }

    aResult.AppendElement(keyframeObject);
  }
}

void
KeyframeEffectReadOnly::GetFrames(JSContext*& aCx,
                                  nsTArray<JSObject*>& aResult,
                                  ErrorResult& aRv)
{
  // Use the specified frames if we have any
  if (!mFrames.IsEmpty()) {
    GetFramesFromFrames(aCx, mFrames, aResult, aRv);
    return;
  }

  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 BaseComputedKeyframe dictionary members.
    BaseComputedKeyframe 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);
    }

    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);
  }
}

/* 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::ShouldBlockAsyncTransformAnimations(
  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::TransformWithGeometricProperties;
      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 UnrestrictedDoubleOrKeyframeAnimationOptions& aOptions,
    ErrorResult& aRv)
{
  return ConstructKeyframeEffect<KeyframeEffect>(aGlobal, aTarget, aFrames,
                                                 aOptions, aRv);
}

void KeyframeEffect::NotifySpecifiedTimingUpdated()
{
  // Use the same document for a pseudo element and its parent element.
  nsAutoAnimationMutationBatch mb(mTarget->OwnerDoc());

  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