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gecko-dev/dom/animation/KeyframeUtils.cpp

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/* 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/KeyframeUtils.h"
#include "mozilla/AnimationUtils.h"
#include "mozilla/ErrorResult.h"
#include "mozilla/Move.h"
#include "mozilla/RangedArray.h"
#include "mozilla/ServoBindings.h"
#include "mozilla/StyleAnimationValue.h"
#include "mozilla/TimingParams.h"
#include "mozilla/dom/BaseKeyframeTypesBinding.h" // For FastBaseKeyframe etc.
#include "mozilla/dom/Element.h"
#include "mozilla/dom/KeyframeEffectBinding.h"
#include "mozilla/dom/KeyframeEffectReadOnly.h" // For PropertyValuesPair etc.
#include "jsapi.h" // For ForOfIterator etc.
#include "nsClassHashtable.h"
#include "nsCSSParser.h"
#include "nsCSSPropertyIDSet.h"
#include "nsCSSProps.h"
#include "nsCSSPseudoElements.h" // For CSSPseudoElementType
#include "nsTArray.h"
#include <algorithm> // For std::stable_sort
namespace mozilla {
// ------------------------------------------------------------------
//
// Internal data types
//
// ------------------------------------------------------------------
// This is used while calculating paced spacing. If the keyframe is not pacable,
// we set its cumulative distance to kNotPaceable, so we can use this to check.
const double kNotPaceable = -1.0;
// For the aAllowList parameter of AppendStringOrStringSequence and
// GetPropertyValuesPairs.
enum class ListAllowance { eDisallow, eAllow };
/**
* A comparator to sort nsCSSPropertyID values such that longhands are sorted
* before shorthands, and shorthands with fewer components are sorted before
* shorthands with more components.
*
* Using this allows us to prioritize values specified by longhands (or smaller
* shorthand subsets) when longhands and shorthands are both specified
* on the one keyframe.
*
* Example orderings that result from this:
*
* margin-left, margin
*
* and:
*
* border-top-color, border-color, border-top, border
*/
class PropertyPriorityComparator
{
public:
PropertyPriorityComparator()
: mSubpropertyCountInitialized(false) {}
bool Equals(nsCSSPropertyID aLhs, nsCSSPropertyID aRhs) const
{
return aLhs == aRhs;
}
bool LessThan(nsCSSPropertyID aLhs,
nsCSSPropertyID aRhs) const
{
bool isShorthandLhs = nsCSSProps::IsShorthand(aLhs);
bool isShorthandRhs = nsCSSProps::IsShorthand(aRhs);
if (isShorthandLhs) {
if (isShorthandRhs) {
// First, sort shorthands by the number of longhands they have.
uint32_t subpropCountLhs = SubpropertyCount(aLhs);
uint32_t subpropCountRhs = SubpropertyCount(aRhs);
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) <
nsCSSProps::PropertyIDLNameSortPosition(aRhs);
}
uint32_t SubpropertyCount(nsCSSPropertyID aProperty) const
{
if (!mSubpropertyCountInitialized) {
PodZero(&mSubpropertyCount);
mSubpropertyCountInitialized = true;
}
if (mSubpropertyCount[aProperty] == 0) {
uint32_t count = 0;
CSSPROPS_FOR_SHORTHAND_SUBPROPERTIES(
p, aProperty, CSSEnabledState::eForAllContent) {
++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;
};
/**
* Adaptor for PropertyPriorityComparator to sort objects which have
* a mProperty member.
*/
template <typename T>
class TPropertyPriorityComparator : PropertyPriorityComparator
{
public:
bool Equals(const T& aLhs, const T& aRhs) const
{
return PropertyPriorityComparator::Equals(aLhs.mProperty, aRhs.mProperty);
}
bool LessThan(const T& aLhs, const T& aRhs) const
{
return PropertyPriorityComparator::LessThan(aLhs.mProperty, aRhs.mProperty);
}
};
/**
* Iterator to walk through a PropertyValuePair array using the ordering
* provided by PropertyPriorityComparator.
*/
class PropertyPriorityIterator
{
public:
explicit PropertyPriorityIterator(
const nsTArray<PropertyValuePair>& aProperties)
: mProperties(aProperties)
{
mSortedPropertyIndices.SetCapacity(mProperties.Length());
for (size_t i = 0, len = mProperties.Length(); i < len; ++i) {
PropertyAndIndex propertyIndex = { mProperties[i].mProperty, i };
mSortedPropertyIndices.AppendElement(propertyIndex);
}
mSortedPropertyIndices.Sort(PropertyAndIndex::Comparator());
}
class Iter
{
public:
explicit Iter(const PropertyPriorityIterator& aParent)
: mParent(aParent)
, mIndex(0) { }
static Iter EndIter(const PropertyPriorityIterator &aParent)
{
Iter iter(aParent);
iter.mIndex = aParent.mSortedPropertyIndices.Length();
return iter;
}
bool operator!=(const Iter& aOther) const
{
return mIndex != aOther.mIndex;
}
Iter& operator++()
{
MOZ_ASSERT(mIndex + 1 <= mParent.mSortedPropertyIndices.Length(),
"Should not seek past end iterator");
mIndex++;
return *this;
}
const PropertyValuePair& operator*()
{
MOZ_ASSERT(mIndex < mParent.mSortedPropertyIndices.Length(),
"Should not try to dereference an end iterator");
return mParent.mProperties[mParent.mSortedPropertyIndices[mIndex].mIndex];
}
private:
const PropertyPriorityIterator& mParent;
size_t mIndex;
};
Iter begin() { return Iter(*this); }
Iter end() { return Iter::EndIter(*this); }
private:
struct PropertyAndIndex
{
nsCSSPropertyID mProperty;
size_t mIndex; // Index of mProperty within mProperties
typedef TPropertyPriorityComparator<PropertyAndIndex> Comparator;
};
const nsTArray<PropertyValuePair>& mProperties;
nsTArray<PropertyAndIndex> mSortedPropertyIndices;
};
/**
* A property-values pair obtained from the open-ended properties
* discovered on a regular keyframe or property-indexed keyframe object.
*
* Single values (as required by a regular keyframe, and as also supported
* on property-indexed keyframes) are stored as the only element in
* mValues.
*/
struct PropertyValuesPair
{
nsCSSPropertyID mProperty;
nsTArray<nsString> mValues;
typedef TPropertyPriorityComparator<PropertyValuesPair> Comparator;
};
/**
* An additional property (for a property-values pair) found on a
* BaseKeyframe or BasePropertyIndexedKeyframe object.
*/
struct AdditionalProperty
{
nsCSSPropertyID 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);
}
};
};
/**
* Data for a segment in a keyframe animation of a given property
* whose value is a StyleAnimationValue.
*
* KeyframeValueEntry is used in GetAnimationPropertiesFromKeyframes
* to gather data for each individual segment.
*/
struct KeyframeValueEntry
{
nsCSSPropertyID mProperty;
StyleAnimationValue mValue;
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;
}
};
};
class ComputedOffsetComparator
{
public:
static bool Equals(const Keyframe& aLhs, const Keyframe& aRhs)
{
return aLhs.mComputedOffset == aRhs.mComputedOffset;
}
static bool LessThan(const Keyframe& aLhs, const Keyframe& aRhs)
{
return aLhs.mComputedOffset < aRhs.mComputedOffset;
}
};
// ------------------------------------------------------------------
//
// Inlined helper methods
//
// ------------------------------------------------------------------
inline bool
IsInvalidValuePair(const PropertyValuePair& aPair, StyleBackendType aBackend)
{
if (aBackend == StyleBackendType::Servo) {
return !aPair.mServoDeclarationBlock;
}
// There are three types of values we store as token streams:
//
// * Shorthand values (where we manually extract the token stream's string
// value) and pass that along to various parsing methods
// * Longhand values with variable references
// * Invalid values
//
// We can distinguish between the last two cases because for invalid values
// we leave the token stream's mPropertyID as eCSSProperty_UNKNOWN.
return !nsCSSProps::IsShorthand(aPair.mProperty) &&
aPair.mValue.GetUnit() == eCSSUnit_TokenStream &&
aPair.mValue.GetTokenStreamValue()->mPropertyID
== eCSSProperty_UNKNOWN;
}
// ------------------------------------------------------------------
//
// Internal helper method declarations
//
// ------------------------------------------------------------------
static void
GetKeyframeListFromKeyframeSequence(JSContext* aCx,
nsIDocument* aDocument,
JS::ForOfIterator& aIterator,
nsTArray<Keyframe>& aResult,
ErrorResult& aRv);
static bool
ConvertKeyframeSequence(JSContext* aCx,
nsIDocument* aDocument,
JS::ForOfIterator& aIterator,
nsTArray<Keyframe>& aResult);
static bool
GetPropertyValuesPairs(JSContext* aCx,
JS::Handle<JSObject*> aObject,
ListAllowance aAllowLists,
nsTArray<PropertyValuesPair>& aResult);
static bool
AppendStringOrStringSequenceToArray(JSContext* aCx,
JS::Handle<JS::Value> aValue,
ListAllowance aAllowLists,
nsTArray<nsString>& aValues);
static bool
AppendValueAsString(JSContext* aCx,
nsTArray<nsString>& aValues,
JS::Handle<JS::Value> aValue);
static PropertyValuePair
MakePropertyValuePair(nsCSSPropertyID aProperty, const nsAString& aStringValue,
nsCSSParser& aParser, nsIDocument* aDocument);
static bool
HasValidOffsets(const nsTArray<Keyframe>& aKeyframes);
static void
MarkAsComputeValuesFailureKey(PropertyValuePair& aPair);
static bool
IsComputeValuesFailureKey(const PropertyValuePair& aPair);
static void
BuildSegmentsFromValueEntries(nsTArray<KeyframeValueEntry>& aEntries,
nsTArray<AnimationProperty>& aResult);
static void
GetKeyframeListFromPropertyIndexedKeyframe(JSContext* aCx,
nsIDocument* aDocument,
JS::Handle<JS::Value> aValue,
nsTArray<Keyframe>& aResult,
ErrorResult& aRv);
static bool
RequiresAdditiveAnimation(const nsTArray<Keyframe>& aKeyframes,
nsIDocument* aDocument);
static void
DistributeRange(const Range<Keyframe>& aSpacingRange,
const Range<Keyframe>& aRangeToAdjust);
static void
DistributeRange(const Range<Keyframe>& aSpacingRange);
static void
PaceRange(const Range<Keyframe>& aKeyframes,
const Range<double>& aCumulativeDistances);
static nsTArray<double>
GetCumulativeDistances(const nsTArray<ComputedKeyframeValues>& aValues,
nsCSSPropertyID aProperty,
nsStyleContext* aStyleContext);
// ------------------------------------------------------------------
//
// Public API
//
// ------------------------------------------------------------------
/* static */ nsTArray<Keyframe>
KeyframeUtils::GetKeyframesFromObject(JSContext* aCx,
nsIDocument* aDocument,
JS::Handle<JSObject*> aFrames,
ErrorResult& aRv)
{
MOZ_ASSERT(!aRv.Failed());
nsTArray<Keyframe> keyframes;
if (!aFrames) {
// The argument was explicitly null meaning no keyframes.
return keyframes;
}
// At this point we know we have an object. We try to convert it to a
// sequence of keyframes first, and if that fails due to not being iterable,
// we try to convert it to a property-indexed keyframe.
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 keyframes;
}
if (iter.valueIsIterable()) {
GetKeyframeListFromKeyframeSequence(aCx, aDocument, iter, keyframes, aRv);
} else {
GetKeyframeListFromPropertyIndexedKeyframe(aCx, aDocument, objectValue,
keyframes, aRv);
}
if (aRv.Failed()) {
MOZ_ASSERT(keyframes.IsEmpty(),
"Should not set any keyframes when there is an error");
return keyframes;
}
// We currently don't support additive animation. However, Web Animations
// says that if you don't have a keyframe at offset 0 or 1, then you should
// synthesize one using an additive zero value when you go to compose style.
// Until we implement additive animations we just throw if we encounter any
// set of keyframes that would put us in that situation.
if (RequiresAdditiveAnimation(keyframes, aDocument)) {
aRv.Throw(NS_ERROR_DOM_ANIM_MISSING_PROPS_ERR);
keyframes.Clear();
}
return keyframes;
}
/* static */ void
KeyframeUtils::ApplySpacing(nsTArray<Keyframe>& aKeyframes,
SpacingMode aSpacingMode,
nsCSSPropertyID aProperty,
nsTArray<ComputedKeyframeValues>& aComputedValues,
nsStyleContext* aStyleContext)
{
if (aKeyframes.IsEmpty()) {
return;
}
nsTArray<double> cumulativeDistances;
if (aSpacingMode == SpacingMode::paced) {
MOZ_ASSERT(IsAnimatableProperty(aProperty),
"Paced property should be animatable");
cumulativeDistances = GetCumulativeDistances(aComputedValues, aProperty,
aStyleContext);
// Reset the computed offsets if using paced spacing.
for (Keyframe& keyframe : aKeyframes) {
keyframe.mComputedOffset = Keyframe::kComputedOffsetNotSet;
}
}
// If the first keyframe has an unspecified offset, fill it in with 0%.
// If there is only a single keyframe, then it gets 100%.
if (aKeyframes.Length() > 1) {
Keyframe& firstElement = aKeyframes[0];
firstElement.mComputedOffset = firstElement.mOffset.valueOr(0.0);
// We will fill in the last keyframe's offset below
} else {
Keyframe& lastElement = aKeyframes.LastElement();
lastElement.mComputedOffset = lastElement.mOffset.valueOr(1.0);
}
// Fill in remaining missing offsets.
const Keyframe* const last = aKeyframes.cend() - 1;
const RangedPtr<Keyframe> begin(aKeyframes.begin(), aKeyframes.Length());
RangedPtr<Keyframe> keyframeA = begin;
while (keyframeA != last) {
// Find keyframe A and keyframe B *between* which we will apply spacing.
RangedPtr<Keyframe> keyframeB = keyframeA + 1;
while (keyframeB->mOffset.isNothing() && keyframeB != last) {
++keyframeB;
}
keyframeB->mComputedOffset = keyframeB->mOffset.valueOr(1.0);
// Fill computed offsets in (keyframe A, keyframe B).
if (aSpacingMode == SpacingMode::distribute) {
DistributeRange(Range<Keyframe>(keyframeA, keyframeB + 1));
} else {
// a) Find Paced A (first paceable keyframe) and
// Paced B (last paceable keyframe) in [keyframe A, keyframe B].
RangedPtr<Keyframe> pacedA = keyframeA;
while (pacedA < keyframeB &&
cumulativeDistances[pacedA - begin] == kNotPaceable) {
++pacedA;
}
RangedPtr<Keyframe> pacedB = keyframeB;
while (pacedB > keyframeA &&
cumulativeDistances[pacedB - begin] == kNotPaceable) {
--pacedB;
}
// As spec says, if there is no paceable keyframe
// in [keyframe A, keyframe B], we let Paced A and Paced B refer to
// keyframe B.
if (pacedA > pacedB) {
pacedA = pacedB = keyframeB;
}
// b) Apply distributing offsets in (keyframe A, Paced A] and
// [Paced B, keyframe B).
DistributeRange(Range<Keyframe>(keyframeA, keyframeB + 1),
Range<Keyframe>(keyframeA + 1, pacedA + 1));
DistributeRange(Range<Keyframe>(keyframeA, keyframeB + 1),
Range<Keyframe>(pacedB, keyframeB));
// c) Apply paced offsets to each paceable keyframe in (Paced A, Paced B).
// We pass the range [Paced A, Paced B] since PaceRange needs the end
// points of the range in order to calculate the correct offset.
PaceRange(Range<Keyframe>(pacedA, pacedB + 1),
Range<double>(&cumulativeDistances[pacedA - begin],
pacedB - pacedA + 1));
// d) Fill in any computed offsets in (Paced A, Paced B) that are still
// not set (e.g. because the keyframe was not paceable, or because the
// cumulative distance between paceable properties was zero).
for (RangedPtr<Keyframe> frame = pacedA + 1; frame < pacedB; ++frame) {
if (frame->mComputedOffset != Keyframe::kComputedOffsetNotSet) {
continue;
}
RangedPtr<Keyframe> start = frame - 1;
RangedPtr<Keyframe> end = frame + 1;
while (end < pacedB &&
end->mComputedOffset == Keyframe::kComputedOffsetNotSet) {
++end;
}
DistributeRange(Range<Keyframe>(start, end + 1));
frame = end;
}
}
keyframeA = keyframeB;
}
}
/* static */ void
KeyframeUtils::ApplyDistributeSpacing(nsTArray<Keyframe>& aKeyframes)
{
nsTArray<ComputedKeyframeValues> emptyArray;
ApplySpacing(aKeyframes, SpacingMode::distribute, eCSSProperty_UNKNOWN,
emptyArray, nullptr);
}
/* static */ nsTArray<ComputedKeyframeValues>
KeyframeUtils::GetComputedKeyframeValues(const nsTArray<Keyframe>& aKeyframes,
dom::Element* aElement,
nsStyleContext* aStyleContext)
{
MOZ_ASSERT(aStyleContext);
MOZ_ASSERT(aElement);
StyleBackendType styleBackend = aElement->OwnerDoc()->GetStyleBackendType();
const size_t len = aKeyframes.Length();
nsTArray<ComputedKeyframeValues> result(len);
for (const Keyframe& frame : aKeyframes) {
nsCSSPropertyIDSet propertiesOnThisKeyframe;
ComputedKeyframeValues* computedValues = result.AppendElement();
for (const PropertyValuePair& pair :
PropertyPriorityIterator(frame.mPropertyValues)) {
MOZ_ASSERT(!pair.mServoDeclarationBlock ||
styleBackend == StyleBackendType::Servo,
"Animation values were parsed using Servo backend but target"
" element is not using Servo backend?");
if (IsInvalidValuePair(pair, styleBackend)) {
continue;
}
// Expand each value into the set of longhands and produce
// a KeyframeValueEntry for each value.
nsTArray<PropertyStyleAnimationValuePair> values;
if (styleBackend == StyleBackendType::Servo) {
if (!StyleAnimationValue::ComputeValues(pair.mProperty,
CSSEnabledState::eForAllContent, aStyleContext,
*pair.mServoDeclarationBlock, values)) {
continue;
}
} else {
// For shorthands, we store the string as a token stream so we need to
// extract that first.
if (nsCSSProps::IsShorthand(pair.mProperty)) {
nsCSSValueTokenStream* tokenStream = pair.mValue.GetTokenStreamValue();
if (!StyleAnimationValue::ComputeValues(pair.mProperty,
CSSEnabledState::eForAllContent, aElement, aStyleContext,
tokenStream->mTokenStream, /* aUseSVGMode */ false, values) ||
IsComputeValuesFailureKey(pair)) {
continue;
}
} else {
if (!StyleAnimationValue::ComputeValues(pair.mProperty,
CSSEnabledState::eForAllContent, aElement, aStyleContext,
pair.mValue, /* aUseSVGMode */ false, values)) {
continue;
}
MOZ_ASSERT(values.Length() == 1,
"Longhand properties should produce a single"
" StyleAnimationValue");
}
}
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;
}
computedValues->AppendElement(value);
propertiesOnThisKeyframe.AddProperty(value.mProperty);
}
}
}
MOZ_ASSERT(result.Length() == aKeyframes.Length(), "Array length mismatch");
return result;
}
/* static */ nsTArray<AnimationProperty>
KeyframeUtils::GetAnimationPropertiesFromKeyframes(
const nsTArray<Keyframe>& aKeyframes,
const nsTArray<ComputedKeyframeValues>& aComputedValues,
nsStyleContext* aStyleContext)
{
MOZ_ASSERT(aKeyframes.Length() == aComputedValues.Length(),
"Array length mismatch");
nsTArray<KeyframeValueEntry> entries(aKeyframes.Length());
const size_t len = aKeyframes.Length();
for (size_t i = 0; i < len; ++i) {
const Keyframe& frame = aKeyframes[i];
for (auto& value : aComputedValues[i]) {
MOZ_ASSERT(frame.mComputedOffset != Keyframe::kComputedOffsetNotSet,
"Invalid computed offset");
KeyframeValueEntry* entry = entries.AppendElement();
entry->mOffset = frame.mComputedOffset;
entry->mProperty = value.mProperty;
entry->mValue = value.mValue;
entry->mTimingFunction = frame.mTimingFunction;
}
}
nsTArray<AnimationProperty> result;
BuildSegmentsFromValueEntries(entries, result);
return result;
}
/* static */ bool
KeyframeUtils::IsAnimatableProperty(nsCSSPropertyID aProperty)
{
if (aProperty == eCSSProperty_UNKNOWN) {
return false;
}
if (!nsCSSProps::IsShorthand(aProperty)) {
return nsCSSProps::kAnimTypeTable[aProperty] != eStyleAnimType_None;
}
CSSPROPS_FOR_SHORTHAND_SUBPROPERTIES(subprop, aProperty,
CSSEnabledState::eForAllContent) {
if (nsCSSProps::kAnimTypeTable[*subprop] != eStyleAnimType_None) {
return true;
}
}
return false;
}
// ------------------------------------------------------------------
//
// Internal helpers
//
// ------------------------------------------------------------------
/**
* Converts a JS object to an IDL sequence<Keyframe>.
*
* @param aCx The JSContext corresponding to |aIterator|.
* @param aDocument The document to use when parsing CSS properties.
* @param aIterator An already-initialized ForOfIterator for the JS
* object to iterate over as a sequence.
* @param aResult The array into which the resulting Keyframe objects will be
* appended.
* @param aRv Out param to store any errors thrown by this function.
*/
static void
GetKeyframeListFromKeyframeSequence(JSContext* aCx,
nsIDocument* aDocument,
JS::ForOfIterator& aIterator,
nsTArray<Keyframe>& aResult,
ErrorResult& aRv)
{
MOZ_ASSERT(!aRv.Failed());
MOZ_ASSERT(aResult.IsEmpty());
// Convert the object in aIterator to a sequence of keyframes producing
// an array of Keyframe objects.
if (!ConvertKeyframeSequence(aCx, aDocument, aIterator, aResult)) {
aRv.Throw(NS_ERROR_FAILURE);
aResult.Clear();
return;
}
// If the sequence<> had zero elements, we won't generate any
// keyframes.
if (aResult.IsEmpty()) {
return;
}
// Check that the keyframes are loosely sorted and with values all
// between 0% and 100%.
if (!HasValidOffsets(aResult)) {
aRv.ThrowTypeError<dom::MSG_INVALID_KEYFRAME_OFFSETS>();
aResult.Clear();
return;
}
}
/**
* Converts a JS object wrapped by the given JS::ForIfIterator to an
* IDL sequence<Keyframe> and stores the resulting Keyframe objects in
* aResult.
*/
static bool
ConvertKeyframeSequence(JSContext* aCx,
nsIDocument* aDocument,
JS::ForOfIterator& aIterator,
nsTArray<Keyframe>& aResult)
{
JS::Rooted<JS::Value> value(aCx);
nsCSSParser parser(aDocument->CSSLoader());
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()) {
dom::ThrowErrorMessage(aCx, dom::MSG_NOT_OBJECT,
"Element of sequence<Keyframe> argument");
return false;
}
// Convert the JS value into a BaseKeyframe dictionary value.
dom::binding_detail::FastBaseKeyframe keyframeDict;
if (!keyframeDict.Init(aCx, value,
"Element of sequence<Keyframe> argument")) {
return false;
}
Keyframe* keyframe = aResult.AppendElement(fallible);
if (!keyframe) {
return false;
}
if (!keyframeDict.mOffset.IsNull()) {
keyframe->mOffset.emplace(keyframeDict.mOffset.Value());
}
ErrorResult rv;
keyframe->mTimingFunction =
TimingParams::ParseEasing(keyframeDict.mEasing, aDocument, rv);
if (rv.MaybeSetPendingException(aCx)) {
return false;
}
// Look for additional property-values pairs on the object.
nsTArray<PropertyValuesPair> propertyValuePairs;
if (value.isObject()) {
JS::Rooted<JSObject*> object(aCx, &value.toObject());
if (!GetPropertyValuesPairs(aCx, object,
ListAllowance::eDisallow,
propertyValuePairs)) {
return false;
}
}
for (PropertyValuesPair& pair : propertyValuePairs) {
MOZ_ASSERT(pair.mValues.Length() == 1);
keyframe->mPropertyValues.AppendElement(
MakePropertyValuePair(pair.mProperty, pair.mValues[0], parser,
aDocument));
// When we go to convert keyframes into arrays of property values we
// call StyleAnimation::ComputeValues. This should normally return true
// but in order to test the case where it does not, BaseKeyframeDict
// includes a chrome-only member that can be set to indicate that
// ComputeValues should fail for shorthand property values on that
// keyframe.
if (nsCSSProps::IsShorthand(pair.mProperty) &&
keyframeDict.mSimulateComputeValuesFailure) {
MarkAsComputeValuesFailureKey(keyframe->mPropertyValues.LastElement());
}
}
}
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;
}
nsCSSPropertyID property =
nsCSSProps::LookupPropertyByIDLName(propName,
CSSEnabledState::eForAllContent);
if (KeyframeUtils::IsAnimatableProperty(property)) {
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 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;
}
/**
* 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, dom::eStringify, dom::eStringify,
*aValues.AppendElement());
}
/**
* Construct a PropertyValuePair parsing the given string into a suitable
* nsCSSValue object.
*
* @param aProperty The CSS property.
* @param aStringValue The property value to parse.
* @param aParser The CSS parser object to use.
* @param aDocument The document to use when parsing.
* @return The constructed PropertyValuePair object.
*/
static PropertyValuePair
MakePropertyValuePair(nsCSSPropertyID aProperty, const nsAString& aStringValue,
nsCSSParser& aParser, nsIDocument* aDocument)
{
MOZ_ASSERT(aDocument);
PropertyValuePair result;
result.mProperty = aProperty;
if (aDocument->GetStyleBackendType() == StyleBackendType::Servo) {
nsCString name = nsCSSProps::GetStringValue(aProperty);
NS_ConvertUTF16toUTF8 value(aStringValue);
RefPtr<ThreadSafeURIHolder> base =
new ThreadSafeURIHolder(aDocument->GetDocumentURI());
RefPtr<ThreadSafeURIHolder> referrer =
new ThreadSafeURIHolder(aDocument->GetDocumentURI());
RefPtr<ThreadSafePrincipalHolder> principal =
new ThreadSafePrincipalHolder(aDocument->NodePrincipal());
nsCString baseString;
aDocument->GetDocumentURI()->GetSpec(baseString);
RefPtr<RawServoDeclarationBlock> servoDeclarationBlock =
Servo_ParseProperty(&name, &value, &baseString,
base, referrer, principal).Consume();
if (servoDeclarationBlock) {
result.mServoDeclarationBlock = servoDeclarationBlock.forget();
return result;
}
}
nsCSSValue value;
if (!nsCSSProps::IsShorthand(aProperty)) {
aParser.ParseLonghandProperty(aProperty,
aStringValue,
aDocument->GetDocumentURI(),
aDocument->GetDocumentURI(),
aDocument->NodePrincipal(),
value);
}
if (value.GetUnit() == eCSSUnit_Null) {
// Either we have a shorthand, or we failed to parse a longhand.
// In either case, store the string value as a token stream.
nsCSSValueTokenStream* tokenStream = new nsCSSValueTokenStream;
tokenStream->mTokenStream = aStringValue;
// We are about to convert a null value to a token stream value but
// by leaving the mPropertyID as unknown, we will be able to
// distinguish between invalid values and valid token stream values
// (e.g. values with variable references).
MOZ_ASSERT(tokenStream->mPropertyID == eCSSProperty_UNKNOWN,
"The property of a token stream should be initialized"
" to unknown");
// By leaving mShorthandPropertyID as unknown, we ensure that when
// we call nsCSSValue::AppendToString we get back the string stored
// in mTokenStream.
MOZ_ASSERT(tokenStream->mShorthandPropertyID == eCSSProperty_UNKNOWN,
"The shorthand property of a token stream should be initialized"
" to unknown");
value.SetTokenStreamValue(tokenStream);
} else {
// If we succeeded in parsing with Gecko, but not Servo the animation is
// not going to work since, for the purposes of animation, we're going to
// ignore |mValue| when the backend is Servo.
NS_WARNING_ASSERTION(aDocument->GetStyleBackendType() !=
StyleBackendType::Servo,
"Gecko succeeded in parsing where Servo failed");
}
result.mValue = value;
return result;
}
/**
* 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<Keyframe>& aKeyframes)
{
double offset = 0.0;
for (const Keyframe& keyframe : aKeyframes) {
if (keyframe.mOffset) {
double thisOffset = keyframe.mOffset.value();
if (thisOffset < offset || thisOffset > 1.0f) {
return false;
}
offset = thisOffset;
}
}
return true;
}
/**
* Takes a property-value pair for a shorthand property and modifies the
* value to indicate that when we call StyleAnimationValue::ComputeValues on
* that value we should behave as if that function had failed.
*
* @param aPair The PropertyValuePair to modify. |aPair.mProperty| must be
* a shorthand property.
*/
static void
MarkAsComputeValuesFailureKey(PropertyValuePair& aPair)
{
MOZ_ASSERT(nsCSSProps::IsShorthand(aPair.mProperty),
"Only shorthand property values can be marked as failure values");
// We store shorthand values as nsCSSValueTokenStream objects whose mProperty
// and mShorthandPropertyID are eCSSProperty_UNKNOWN and whose mTokenStream
// member contains the shorthand property's value as a string.
//
// We need to leave mShorthandPropertyID as eCSSProperty_UNKNOWN so that
// nsCSSValue::AppendToString returns the mTokenStream value, but we can
// update mPropertyID to a special value to indicate that this is
// a special failure sentinel.
nsCSSValueTokenStream* tokenStream = aPair.mValue.GetTokenStreamValue();
MOZ_ASSERT(tokenStream->mPropertyID == eCSSProperty_UNKNOWN,
"Shorthand value should initially have an unknown property ID");
tokenStream->mPropertyID = eCSSPropertyExtra_no_properties;
}
/**
* Returns true if |aPair| is a property-value pair on which we have
* previously called MarkAsComputeValuesFailureKey (and hence we should
* simulate failure when calling StyleAnimationValue::ComputeValues using its
* value).
*
* @param aPair The property-value pair to test.
* @return True if |aPair| represents a failure value.
*/
static bool
IsComputeValuesFailureKey(const PropertyValuePair& aPair)
{
return nsCSSProps::IsShorthand(aPair.mProperty) &&
aPair.mValue.GetTokenStreamValue()->mPropertyID ==
eCSSPropertyExtra_no_properties;
}
/**
* 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);
// 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.
//
// Typically, for each property in |aEntries|, we expect there to be at least
// one KeyframeValueEntry with offset 0.0, and at least one with offset 1.0.
// However, since it is possible that when building |aEntries|, the call to
// StyleAnimationValue::ComputeValues might fail, this can't be guaranteed.
// Furthermore, since we don't yet implement additive animation and hence
// don't have sensible fallback behavior when these values are missing, the
// following loop takes care to identify properties that lack a value at
// offset 0.0/1.0 and drops those properties from |aResult|.
nsCSSPropertyID lastProperty = eCSSProperty_UNKNOWN;
AnimationProperty* animationProperty = nullptr;
size_t i = 0, n = aEntries.Length();
while (i < n) {
// Check that the last property ends with an entry at offset 1.
if (i + 1 == n) {
if (aEntries[i].mOffset != 1.0f && animationProperty) {
aResult.RemoveElementAt(aResult.Length() - 1);
animationProperty = nullptr;
}
break;
}
MOZ_ASSERT(aEntries[i].mProperty != eCSSProperty_UNKNOWN &&
aEntries[i + 1].mProperty != eCSSProperty_UNKNOWN,
"Each entry should specify a valid property");
// Skip properties that don't have an entry with offset 0.
if (aEntries[i].mProperty != lastProperty &&
aEntries[i].mOffset != 0.0f) {
// Since the entries are sorted by offset for a given property, and
// since we don't update |lastProperty|, we will keep hitting this
// condition until we change property.
++i;
continue;
}
// Drop properties that don't end with an entry with offset 1.
if (aEntries[i].mProperty != aEntries[i + 1].mProperty &&
aEntries[i].mOffset != 1.0f) {
if (animationProperty) {
aResult.RemoveElementAt(aResult.Length() - 1);
animationProperty = nullptr;
}
++i;
continue;
}
// 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 &&
aEntries[j + 1].mProperty == aEntries[j].mProperty) {
++j;
}
} else if (aEntries[i].mOffset == 1.0f) {
if (aEntries[i + 1].mOffset == 1.0f &&
aEntries[i + 1].mProperty == aEntries[i].mProperty) {
// We need to generate a final zero-length segment.
j = i + 1;
while (j + 1 < n &&
aEntries[j + 1].mOffset == 1.0f &&
aEntries[j + 1].mProperty == aEntries[j].mProperty) {
++j;
}
} else {
// New property.
MOZ_ASSERT(aEntries[i].mProperty != aEntries[i + 1].mProperty);
animationProperty = nullptr;
++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);
MOZ_ASSERT(!animationProperty);
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 representing a property-indexed keyframe into
* an array of Keyframe objects.
*
* @param aCx The JSContext for |aValue|.
* @param aDocument The document to use when parsing CSS properties.
* @param aValue The JS object.
* @param aResult The array into which the resulting AnimationProperty
* objects will be appended.
* @param aRv Out param to store any errors thrown by this function.
*/
static void
GetKeyframeListFromPropertyIndexedKeyframe(JSContext* aCx,
nsIDocument* aDocument,
JS::Handle<JS::Value> aValue,
nsTArray<Keyframe>& aResult,
ErrorResult& aRv)
{
MOZ_ASSERT(aValue.isObject());
MOZ_ASSERT(aResult.IsEmpty());
MOZ_ASSERT(!aRv.Failed());
// Convert the object to a property-indexed keyframe dictionary to
// get its explicit dictionary members.
dom::binding_detail::FastBasePropertyIndexedKeyframe keyframeDict;
if (!keyframeDict.Init(aCx, aValue, "BasePropertyIndexedKeyframe argument",
false)) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
Maybe<ComputedTimingFunction> easing =
TimingParams::ParseEasing(keyframeDict.mEasing, aDocument, aRv);
if (aRv.Failed()) {
return;
}
// 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;
}
// Create a set of keyframes for each property.
nsCSSParser parser(aDocument->CSSLoader());
nsClassHashtable<nsFloatHashKey, Keyframe> processedKeyframes;
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 values 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;
}
size_t n = pair.mValues.Length() - 1;
size_t i = 0;
for (const nsString& stringValue : pair.mValues) {
double offset = i++ / double(n);
Keyframe* keyframe = processedKeyframes.LookupOrAdd(offset);
if (keyframe->mPropertyValues.IsEmpty()) {
keyframe->mTimingFunction = easing;
keyframe->mComputedOffset = offset;
}
keyframe->mPropertyValues.AppendElement(
MakePropertyValuePair(pair.mProperty, stringValue, parser, aDocument));
}
}
aResult.SetCapacity(processedKeyframes.Count());
for (auto iter = processedKeyframes.Iter(); !iter.Done(); iter.Next()) {
aResult.AppendElement(Move(*iter.UserData()));
}
aResult.Sort(ComputedOffsetComparator());
}
/**
* Returns true if the supplied set of keyframes has keyframe values for
* any property for which it does not also supply a value for the 0% and 100%
* offsets. In this case we are supposed to synthesize an additive zero value
* but since we don't support additive animation yet we can't support this
* case. We try to detect that here so we can throw an exception. The check is
* not entirely accurate but should detect most common cases.
*
* @param aKeyframes The set of keyframes to analyze.
* @param aDocument The document to use when parsing keyframes so we can
* try to detect where we have an invalid value at 0%/100%.
*/
static bool
RequiresAdditiveAnimation(const nsTArray<Keyframe>& aKeyframes,
nsIDocument* aDocument)
{
// We are looking to see if that every property referenced in |aKeyframes|
// has a valid property at offset 0.0 and 1.0. The check as to whether a
// property is valid or not, however, is not precise. We only check if the
// property can be parsed, NOT whether it can also be converted to a
// StyleAnimationValue since doing that requires a target element bound to
// a document which we might not always have at the point where we want to
// perform this check.
//
// This is only a temporary measure until we implement additive animation.
// So as long as this check catches most cases, and we don't do anything
// horrible in one of the cases we can't detect, it should be sufficient.
nsCSSPropertyIDSet properties; // All properties encountered.
nsCSSPropertyIDSet propertiesWithFromValue; // Those with a defined 0% value.
nsCSSPropertyIDSet propertiesWithToValue; // Those with a defined 100% value.
auto addToPropertySets = [&](nsCSSPropertyID aProperty, double aOffset) {
properties.AddProperty(aProperty);
if (aOffset == 0.0) {
propertiesWithFromValue.AddProperty(aProperty);
} else if (aOffset == 1.0) {
propertiesWithToValue.AddProperty(aProperty);
}
};
StyleBackendType styleBackend = aDocument->GetStyleBackendType();
for (size_t i = 0, len = aKeyframes.Length(); i < len; i++) {
const Keyframe& frame = aKeyframes[i];
// We won't have called ApplySpacing when this is called so
// we can't use frame.mComputedOffset. Instead we do a rough version
// of that algorithm that substitutes null offsets with 0.0 for the first
// frame, 1.0 for the last frame, and 0.5 for everything else.
double computedOffset = i == len - 1
? 1.0
: i == 0 ? 0.0 : 0.5;
double offsetToUse = frame.mOffset
? frame.mOffset.value()
: computedOffset;
for (const PropertyValuePair& pair : frame.mPropertyValues) {
if (IsInvalidValuePair(pair, styleBackend)) {
continue;
}
if (nsCSSProps::IsShorthand(pair.mProperty)) {
if (styleBackend == StyleBackendType::Gecko) {
nsCSSValueTokenStream* tokenStream =
pair.mValue.GetTokenStreamValue();
nsCSSParser parser(aDocument->CSSLoader());
if (!parser.IsValueValidForProperty(pair.mProperty,
tokenStream->mTokenStream)) {
continue;
}
}
// For the Servo backend, invalid shorthand values are represented by
// a null mServoDeclarationBlock member which we skip above in
// IsInvalidValuePair.
MOZ_ASSERT(styleBackend != StyleBackendType::Servo ||
pair.mServoDeclarationBlock);
CSSPROPS_FOR_SHORTHAND_SUBPROPERTIES(
prop, pair.mProperty, CSSEnabledState::eForAllContent) {
addToPropertySets(*prop, offsetToUse);
}
} else {
addToPropertySets(pair.mProperty, offsetToUse);
}
}
}
return !propertiesWithFromValue.Equals(properties) ||
!propertiesWithToValue.Equals(properties);
}
/**
* Evenly distribute the computed offsets in (A, B).
* We pass the range keyframes in [A, B] and use A, B to calculate distributing
* computed offsets in (A, B). The second range, aRangeToAdjust, is passed, so
* we can know which keyframe we want to apply to. aRangeToAdjust should be in
* the range of aSpacingRange.
*
* @param aSpacingRange The sequence of keyframes between whose endpoints we
* should apply distribute spacing.
* @param aRangeToAdjust The range of keyframes we want to apply to.
*/
static void
DistributeRange(const Range<Keyframe>& aSpacingRange,
const Range<Keyframe>& aRangeToAdjust)
{
MOZ_ASSERT(aRangeToAdjust.begin() >= aSpacingRange.begin() &&
aRangeToAdjust.end() <= aSpacingRange.end(),
"Out of range");
const size_t n = aSpacingRange.length() - 1;
const double startOffset = aSpacingRange[0].mComputedOffset;
const double diffOffset = aSpacingRange[n].mComputedOffset - startOffset;
for (auto iter = aRangeToAdjust.begin();
iter != aRangeToAdjust.end();
++iter) {
size_t index = iter - aSpacingRange.begin();
iter->mComputedOffset = startOffset + double(index) / n * diffOffset;
}
}
/**
* Overload of DistributeRange to apply distribute spacing to all keyframes in
* between the endpoints of the given range.
*
* @param aSpacingRange The sequence of keyframes between whose endpoints we
* should apply distribute spacing.
*/
static void
DistributeRange(const Range<Keyframe>& aSpacingRange)
{
// We don't need to apply distribute spacing to keyframe A and keyframe B.
DistributeRange(aSpacingRange,
Range<Keyframe>(aSpacingRange.begin() + 1,
aSpacingRange.end() - 1));
}
/**
* Apply paced spacing to all paceable keyframes in between the endpoints of the
* given range.
*
* @param aKeyframes The range of keyframes between whose endpoints we should
* apply paced spacing. Both endpoints should be paceable, i.e. the
* corresponding elements in |aCumulativeDist| should not be kNotPaceable.
* Within this function, we refer to the start and end points of this range
* as Paced A and Paced B respectively in keeping with the notation used in
* the spec.
* @param aCumulativeDistances The sequence of cumulative distances of the paced
* property as returned by GetCumulativeDistances(). This acts as a
* parallel range to |aKeyframes|.
*/
static void
PaceRange(const Range<Keyframe>& aKeyframes,
const Range<double>& aCumulativeDistances)
{
MOZ_ASSERT(aKeyframes.length() == aCumulativeDistances.length(),
"Range length mismatch");
const size_t len = aKeyframes.length();
// If there is nothing between the end points, there is nothing to space.
if (len < 3) {
return;
}
const double distA = *(aCumulativeDistances.begin());
const double distB = *(aCumulativeDistances.end() - 1);
MOZ_ASSERT(distA != kNotPaceable && distB != kNotPaceable,
"Both Paced A and Paced B should be paceable");
// If the total distance is zero, we should fall back to distribute spacing.
// The caller will fill-in any keyframes without a computed offset using
// distribute spacing so we can just return here.
if (distA == distB) {
return;
}
const RangedPtr<Keyframe> pacedA = aKeyframes.begin();
const RangedPtr<Keyframe> pacedB = aKeyframes.end() - 1;
MOZ_ASSERT(pacedA->mComputedOffset != Keyframe::kComputedOffsetNotSet &&
pacedB->mComputedOffset != Keyframe::kComputedOffsetNotSet,
"Both Paced A and Paced B should have valid computed offsets");
// Apply computed offset.
const double offsetA = pacedA->mComputedOffset;
const double diffOffset = pacedB->mComputedOffset - offsetA;
const double initialDist = distA;
const double totalDist = distB - initialDist;
for (auto iter = pacedA + 1; iter != pacedB; ++iter) {
size_t k = iter - aKeyframes.begin();
if (aCumulativeDistances[k] == kNotPaceable) {
continue;
}
double dist = aCumulativeDistances[k] - initialDist;
iter->mComputedOffset = offsetA + diffOffset * dist / totalDist;
}
}
/**
* Get cumulative distances for the paced property.
*
* @param aValues The computed values returned by GetComputedKeyframeValues.
* @param aPacedProperty The paced property.
* @param aStyleContext The style context for computing distance on transform.
* @return The cumulative distances for the paced property. The length will be
* the same as aValues.
*/
static nsTArray<double>
GetCumulativeDistances(const nsTArray<ComputedKeyframeValues>& aValues,
nsCSSPropertyID aPacedProperty,
nsStyleContext* aStyleContext)
{
// a) If aPacedProperty is a shorthand property, get its components.
// Otherwise, just add the longhand property into the set.
size_t pacedPropertyCount = 0;
nsCSSPropertyIDSet pacedPropertySet;
bool isShorthand = nsCSSProps::IsShorthand(aPacedProperty);
if (isShorthand) {
CSSPROPS_FOR_SHORTHAND_SUBPROPERTIES(p, aPacedProperty,
CSSEnabledState::eForAllContent) {
pacedPropertySet.AddProperty(*p);
++pacedPropertyCount;
}
} else {
pacedPropertySet.AddProperty(aPacedProperty);
pacedPropertyCount = 1;
}
// b) Search each component (shorthand) or the longhand property, and
// calculate the cumulative distances of paceable keyframe pairs.
const size_t len = aValues.Length();
nsTArray<double> cumulativeDistances(len);
// cumulativeDistances is a parallel array to |aValues|, so set its length to
// the length of |aValues|.
cumulativeDistances.SetLength(len);
ComputedKeyframeValues prevPacedValues;
size_t preIdx = 0;
for (size_t i = 0; i < len; ++i) {
// Find computed values of the paced property.
ComputedKeyframeValues pacedValues;
for (const PropertyStyleAnimationValuePair& pair : aValues[i]) {
if (pacedPropertySet.HasProperty(pair.mProperty)) {
pacedValues.AppendElement(pair);
}
}
// Check we have values for all the paceable longhand components.
if (pacedValues.Length() != pacedPropertyCount) {
// This keyframe is not paceable, assign kNotPaceable and skip it.
cumulativeDistances[i] = kNotPaceable;
continue;
}
// Sort the pacedValues first, so the order of subproperties of
// pacedValues is always the same as that of prevPacedValues.
if (isShorthand) {
pacedValues.Sort(
TPropertyPriorityComparator<PropertyStyleAnimationValuePair>());
}
if (prevPacedValues.IsEmpty()) {
// This is the first paceable keyframe so its cumulative distance is 0.0.
cumulativeDistances[i] = 0.0;
} else {
double dist = 0.0;
if (isShorthand) {
// Apply the distance by the square root of the sum of squares of
// longhand component distances.
for (size_t propIdx = 0; propIdx < pacedPropertyCount; ++propIdx) {
nsCSSPropertyID prop = prevPacedValues[propIdx].mProperty;
MOZ_ASSERT(pacedValues[propIdx].mProperty == prop,
"Property mismatch");
double componentDistance = 0.0;
if (StyleAnimationValue::ComputeDistance(
prop,
prevPacedValues[propIdx].mValue,
pacedValues[propIdx].mValue,
aStyleContext,
componentDistance)) {
dist += componentDistance * componentDistance;
}
}
dist = sqrt(dist);
} else {
// If the property is longhand, we just use the 1st value.
// If ComputeDistance() fails, |dist| will remain zero so there will be
// no distance between the previous paced value and this value.
Unused <<
StyleAnimationValue::ComputeDistance(aPacedProperty,
prevPacedValues[0].mValue,
pacedValues[0].mValue,
aStyleContext,
dist);
}
cumulativeDistances[i] = cumulativeDistances[preIdx] + dist;
}
prevPacedValues.SwapElements(pacedValues);
preIdx = i;
}
return cumulativeDistances;
}
} // namespace mozilla
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