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/FloatingPoint.h"
#include "AnimationCommon.h"
#include "nsCSSPropertySet.h"
#include "nsCSSProps.h" // For nsCSSProps::PropHasFlags
#include "nsStyleUtil.h"

namespace mozilla {

void
ComputedTimingFunction::Init(const nsTimingFunction &aFunction)
{
  mType = aFunction.mType;
  if (nsTimingFunction::IsSplineType(mType)) {
    mTimingFunction.Init(aFunction.mFunc.mX1, aFunction.mFunc.mY1,
                         aFunction.mFunc.mX2, aFunction.mFunc.mY2);
  } else {
    mSteps = aFunction.mSteps;
    mStepSyntax = aFunction.mStepSyntax;
  }
}

static inline double
StepEnd(uint32_t aSteps, double aPortion)
{
  MOZ_ASSERT(0.0 <= aPortion && aPortion <= 1.0, "out of range");
  uint32_t step = uint32_t(aPortion * aSteps); // floor
  return double(step) / double(aSteps);
}

double
ComputedTimingFunction::GetValue(double aPortion) const
{
  if (HasSpline()) {
    return mTimingFunction.GetSplineValue(aPortion);
  }
  if (mType == nsTimingFunction::Type::StepStart) {
    // There are diagrams in the spec that seem to suggest this check
    // and the bounds point should not be symmetric with StepEnd, but
    // should actually step up at rather than immediately after the
    // fraction points.  However, we rely on rounding negative values
    // up to zero, so we can't do that.  And it's not clear the spec
    // really meant it.
    return 1.0 - StepEnd(mSteps, 1.0 - aPortion);
  }
  MOZ_ASSERT(mType == nsTimingFunction::Type::StepEnd, "bad type");
  return StepEnd(mSteps, aPortion);
}

int32_t
ComputedTimingFunction::Compare(const ComputedTimingFunction& aRhs) const
{
  if (mType != aRhs.mType) {
    return int32_t(mType) - int32_t(aRhs.mType);
  }

  if (mType == nsTimingFunction::Type::CubicBezier) {
    int32_t order = mTimingFunction.Compare(aRhs.mTimingFunction);
    if (order != 0) {
      return order;
    }
  } else if (mType == nsTimingFunction::Type::StepStart ||
             mType == nsTimingFunction::Type::StepEnd) {
    if (mSteps != aRhs.mSteps) {
      return int32_t(mSteps) - int32_t(aRhs.mSteps);
    }
    if (mStepSyntax != aRhs.mStepSyntax) {
      return int32_t(mStepSyntax) - int32_t(aRhs.mStepSyntax);
    }
  }

  return 0;
}

void
ComputedTimingFunction::AppendToString(nsAString& aResult) const
{
  switch (mType) {
    case nsTimingFunction::Type::CubicBezier:
      nsStyleUtil::AppendCubicBezierTimingFunction(mTimingFunction.X1(),
                                                   mTimingFunction.Y1(),
                                                   mTimingFunction.X2(),
                                                   mTimingFunction.Y2(),
                                                   aResult);
      break;
    case nsTimingFunction::Type::StepStart:
    case nsTimingFunction::Type::StepEnd:
      nsStyleUtil::AppendStepsTimingFunction(mType, mSteps, mStepSyntax,
                                             aResult);
      break;
    default:
      nsStyleUtil::AppendCubicBezierKeywordTimingFunction(mType, aResult);
      break;
  }
}

// In the Web Animations model, the iteration progress can be outside the range
// [0.0, 1.0] but it shouldn't be Infinity.
const double ComputedTiming::kNullProgress = PositiveInfinity<double>();

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,
  nsCSSPseudoElements::Type aPseudoType,
  const AnimationTiming& aTiming)
  : AnimationEffectReadOnly(aDocument)
  , mTarget(aTarget)
  , mTiming(aTiming)
  , mPseudoType(aPseudoType)
{
  MOZ_ASSERT(aTarget, "null animation target is not yet supported");
  ResetIsRunningOnCompositor();
}

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

void
KeyframeEffectReadOnly::SetTiming(const AnimationTiming& aTiming)
{
  if (mTiming == aTiming) {
    return;
  }
  mTiming = aTiming;
  if (mAnimation) {
    mAnimation->NotifyEffectTimingUpdated();
  }
}

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;
}

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

  // Currently we expect negative durations to be picked up during CSS
  // parsing but when we start receiving timing parameters from other sources
  // we will need to clamp negative durations here.
  // For now, if we're hitting this it probably means we're overflowing
  // integer arithmetic in mozilla::TimeStamp.
  MOZ_ASSERT(aTiming.mIterationDuration >= zeroDuration,
             "Expecting iteration duration >= 0");

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

  result.mActiveDuration = ActiveDuration(aTiming);

  // 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 >= aTiming.mDelay + result.mActiveDuration) {
    result.mPhase = ComputedTiming::AnimationPhase_After;
    if (!aTiming.FillsForwards()) {
      // The animation isn't active or filling at this time.
      result.mProgress = ComputedTiming::kNullProgress;
      return result;
    }
    activeTime = result.mActiveDuration;
    // Note that infinity == floor(infinity) so this will also be true when we
    // have finished an infinitely repeating animation of zero duration.
    isEndOfFinalIteration =
      aTiming.mIterationCount != 0.0 &&
      aTiming.mIterationCount == floor(aTiming.mIterationCount);
  } else if (localTime < aTiming.mDelay) {
    result.mPhase = ComputedTiming::AnimationPhase_Before;
    if (!aTiming.FillsBackwards()) {
      // The animation isn't active or filling at this time.
      result.mProgress = ComputedTiming::kNullProgress;
      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;
  }

  // Get the position within the current iteration.
  StickyTimeDuration iterationTime;
  if (aTiming.mIterationDuration != zeroDuration) {
    iterationTime = isEndOfFinalIteration
                    ? StickyTimeDuration(aTiming.mIterationDuration)
                    : activeTime % aTiming.mIterationDuration;
  } /* else, iterationTime is zero */

  // Determine the 0-based index of the current iteration.
  if (isEndOfFinalIteration) {
    result.mCurrentIteration =
      aTiming.mIterationCount == NS_IEEEPositiveInfinity()
      ? UINT64_MAX // FIXME: When we return this via the API we'll need
                   // to make sure it ends up being infinity.
      : static_cast<uint64_t>(aTiming.mIterationCount) - 1;
  } else if (activeTime == zeroDuration) {
    // If the active time is zero we're either in the first iteration
    // (including filling backwards) or we have finished an animation with an
    // iteration duration of zero that is filling forwards (but we're not at
    // the exact end of an iteration since we deal with that above).
    result.mCurrentIteration =
      result.mPhase == ComputedTiming::AnimationPhase_After
      ? static_cast<uint64_t>(aTiming.mIterationCount) // floor
      : 0;
  } else {
    result.mCurrentIteration =
      static_cast<uint64_t>(activeTime / aTiming.mIterationDuration); // floor
  }

  // Normalize the iteration time into a fraction of the iteration duration.
  if (result.mPhase == ComputedTiming::AnimationPhase_Before) {
    result.mProgress = 0.0;
  } else if (result.mPhase == ComputedTiming::AnimationPhase_After) {
    result.mProgress = isEndOfFinalIteration
                       ? 1.0
                       : fmod(aTiming.mIterationCount, 1.0f);
  } else {
    // We are in the active phase so the iteration duration can't be zero.
    MOZ_ASSERT(aTiming.mIterationDuration != zeroDuration,
               "In the active phase of a zero-duration animation?");
    result.mProgress = aTiming.mIterationDuration == TimeDuration::Forever()
                       ? 0.0
                       : iterationTime / aTiming.mIterationDuration;
  }

  bool thisIterationReverse = false;
  switch (aTiming.mDirection) {
    case NS_STYLE_ANIMATION_DIRECTION_NORMAL:
      thisIterationReverse = false;
      break;
    case NS_STYLE_ANIMATION_DIRECTION_REVERSE:
      thisIterationReverse = true;
      break;
    case NS_STYLE_ANIMATION_DIRECTION_ALTERNATE:
      thisIterationReverse = (result.mCurrentIteration & 1) == 1;
      break;
    case NS_STYLE_ANIMATION_DIRECTION_ALTERNATE_REVERSE:
      thisIterationReverse = (result.mCurrentIteration & 1) == 0;
      break;
  }
  if (thisIterationReverse) {
    result.mProgress = 1.0 - result.mProgress;
  }

  return result;
}

StickyTimeDuration
KeyframeEffectReadOnly::ActiveDuration(const AnimationTiming& aTiming)
{
  if (aTiming.mIterationCount == mozilla::PositiveInfinity<float>()) {
    // An animation that repeats forever has an infinite active duration
    // unless its iteration duration is zero, in which case it has a zero
    // active duration.
    const StickyTimeDuration zeroDuration;
    return aTiming.mIterationDuration == zeroDuration
           ? zeroDuration
           : StickyTimeDuration::Forever();
  }
  return StickyTimeDuration(
    aTiming.mIterationDuration.MultDouble(aTiming.mIterationCount));
}

// 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 != ComputedTiming::kNullProgress;
}

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

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::ComposeStyle(nsRefPtr<AnimValuesStyleRule>& aStyleRule,
                                     nsCSSPropertySet& aSetProperties)
{
  ComputedTiming computedTiming = GetComputedTiming();

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

  MOZ_ASSERT(0.0 <= computedTiming.mProgress &&
             computedTiming.mProgress <= 1.0,
             "iteration progress should be in [0-1]");

  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 AnimationCollection 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) {
      MOZ_ASSERT(segment->mFromKey < segment->mToKey, "incorrect keys");
      ++segment;
      if (segment == segmentEnd) {
        MOZ_ASSERT_UNREACHABLE("incorrect iteration progress");
        break; // in order to continue in outer loop (just below)
      }
      MOZ_ASSERT(segment->mFromKey == (segment-1)->mToKey, "incorrect keys");
    }
    if (segment == segmentEnd) {
      continue;
    }
    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 - segment->mFromKey) /
      (segment->mToKey - segment->mFromKey);
    double valuePosition =
      segment->mTimingFunction.GetValue(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 (bool isPropertyRunningOnCompositor : mIsPropertyRunningOnCompositor) {
    if (isPropertyRunningOnCompositor) {
      return true;
    }
  }
  return false;
}

void
KeyframeEffectReadOnly::SetIsRunningOnCompositor(nsCSSProperty aProperty,
                                                 bool aIsRunning)
{
  static_assert(
    MOZ_ARRAY_LENGTH(LayerAnimationInfo::sRecords) ==
      MOZ_ARRAY_LENGTH(mIsPropertyRunningOnCompositor),
    "The length of mIsPropertyRunningOnCompositor should equal to"
    "the length of LayserAnimationInfo::sRecords");
  MOZ_ASSERT(nsCSSProps::PropHasFlags(aProperty,
                                      CSS_PROPERTY_CAN_ANIMATE_ON_COMPOSITOR),
             "Property being animated on compositor is a recognized "
             "compositor-animatable property");
  const auto& info = LayerAnimationInfo::sRecords;
  for (size_t i = 0; i < ArrayLength(mIsPropertyRunningOnCompositor); i++) {
    if (info[i].mProperty == aProperty) {
      mIsPropertyRunningOnCompositor[i] = aIsRunning;
      return;
    }
  }
}

// We need to define this here since Animation is an incomplete type
// (forward-declared) in the header.
KeyframeEffectReadOnly::~KeyframeEffectReadOnly()
{
}

void
KeyframeEffectReadOnly::ResetIsRunningOnCompositor()
{
  for (bool& isPropertyRunningOnCompositor : mIsPropertyRunningOnCompositor) {
    isPropertyRunningOnCompositor = false;
  }
}

struct KeyframeValueEntry
{
  float mOffset;
  nsCSSProperty mProperty;
  nsString mValue;
  const ComputedTimingFunction* mTimingFunction;

  bool operator==(const KeyframeValueEntry& aRhs) const
  {
    NS_ASSERTION(mOffset != aRhs.mOffset || mProperty != aRhs.mProperty,
                 "shouldn't have duplicate (offset, property) pairs");
    return false;
  }

  bool operator<(const KeyframeValueEntry& aRhs) const
  {
    NS_ASSERTION(mOffset != aRhs.mOffset || mProperty != aRhs.mProperty,
                 "shouldn't have duplicate (offset, property) pairs");

    // First, sort by offset.
    if (mOffset != aRhs.mOffset) {
      return mOffset < aRhs.mOffset;
    }

    // Second, by timing function.
    int32_t order = mTimingFunction->Compare(*aRhs.mTimingFunction);
    if (order != 0) {
      return order < 0;
    }

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

void
KeyframeEffectReadOnly::GetFrames(JSContext*& aCx,
                                  nsTArray<JSObject*>& aResult,
                                  ErrorResult& aRv)
{
  // Collect tuples of the form (offset, property, value, easing) from
  // mProperties, then sort them so we can generate one ComputedKeyframe per
  // offset/easing pair.  We sort secondarily by property IDL name so that we
  // have a uniform order that we set properties on the ComputedKeyframe
  // object.
  nsAutoTArray<KeyframeValueEntry,4> entries;
  for (const AnimationProperty& property : mProperties) {
    if (property.mSegments.IsEmpty()) {
      continue;
    }
    for (size_t i = 0, n = property.mSegments.Length(); i < n; i++) {
      const AnimationPropertySegment& segment = property.mSegments[i];
      KeyframeValueEntry* entry = entries.AppendElement();
      entry->mOffset = segment.mFromKey;
      entry->mProperty = property.mProperty;
      entry->mTimingFunction = &segment.mTimingFunction;
      StyleAnimationValue::UncomputeValue(property.mProperty,
                                          segment.mFromValue,
                                          entry->mValue);
    }
    const AnimationPropertySegment& segment = property.mSegments.LastElement();
    KeyframeValueEntry* entry = entries.AppendElement();
    entry->mOffset = segment.mToKey;
    entry->mProperty = property.mProperty;
    // We don't have the an appropriate animation-timing-function value to use,
    // either from the element or from the 100% keyframe, so we just set it to
    // the animation-timing-value value used on the previous segment.
    entry->mTimingFunction = &segment.mTimingFunction;
    StyleAnimationValue::UncomputeValue(property.mProperty,
                                        segment.mToValue,
                                        entry->mValue);
  }
  entries.Sort();

  for (size_t i = 0, n = entries.Length(); i < n; ) {
    // Create a JS object with the explicit ComputedKeyframe dictionary members.
    ComputedKeyframe keyframeDict;
    keyframeDict.mOffset.SetValue(entries[i].mOffset);
    keyframeDict.mComputedOffset.Construct(entries[i].mOffset);
    keyframeDict.mEasing.Truncate();
    entries[i].mTimingFunction->AppendToString(keyframeDict.mEasing);
    keyframeDict.mComposite.SetValue(CompositeOperation::Replace);

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

    JS::Rooted<JSObject*> keyframe(aCx, &keyframeValue.toObject());

    // Set the property name/value pairs on the JS object.
    do {
      const KeyframeValueEntry& entry = entries[i];
      const char* name = nsCSSProps::PropertyIDLName(entry.mProperty);
      JS::Rooted<JS::Value> value(aCx);
      if (!ToJSValue(aCx, entry.mValue, &value) ||
          !JS_DefineProperty(aCx, keyframe, name, value, JSPROP_ENUMERATE)) {
        aRv.Throw(NS_ERROR_FAILURE);
        return;
      }
      ++i;
    } while (i < n &&
             entries[i].mOffset == entries[i - 1].mOffset &&
             *entries[i].mTimingFunction == *entries[i - 1].mTimingFunction);

    aResult.AppendElement(keyframe);
  }
}

} // namespace dom
} // namespace mozilla