layout/style/nsAnimationManager.h
author Nika Layzell <nika@thelayzells.com>
Tue, 25 Sep 2018 17:34:53 +0200
changeset 507828 5e6dae0c1e5a4939ccd406f14607f7fafffd45a7
parent 474568 238d0908de38dbeed24a2e288b8b25e64087ec7c
child 508163 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1448426 - Wrap windows.h to avoid problematic define statements, r=froydnj,glandium By default, windows.h exposes a large number of problematic define statements which are UpperCamelCase, such as a define from `CreateWindow` to `CreateWindow{A,W}`. As many of these names are generic (e.g. CreateFile, CreateWindow), they can mess up Gecko code that may legitimately have its own methods with the same names. The header also defines some traditional SCREAMING_SNAKE_CASE defines which can mess up our code by conflicting with local values. This patch adds a simple code generator which generates wrappers for these defines, and uses them to wrap the windows.h wrapper using the `stl_wrappers` mechanism, allowing us to use windows.h in more places. Differential Revision: https://phabricator.services.mozilla.com/D10932

/* -*- 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/. */
#ifndef nsAnimationManager_h_
#define nsAnimationManager_h_

#include "mozilla/Attributes.h"
#include "mozilla/ContentEvents.h"
#include "mozilla/EventForwards.h"
#include "AnimationCommon.h"
#include "mozilla/dom/Animation.h"
#include "mozilla/Keyframe.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/TimeStamp.h"
#include "nsISupportsImpl.h"

class nsIGlobalObject;
class ServoComputedData;
struct nsStyleDisplay;
class ServoCSSAnimationBuilder;

namespace mozilla {
class ComputedStyle;
namespace css {
class Declaration;
} /* namespace css */
namespace dom {
class Promise;
} /* namespace dom */

enum class CSSPseudoElementType : uint8_t;
struct NonOwningAnimationTarget;

namespace dom {

class CSSAnimation final : public Animation
{
public:
 explicit CSSAnimation(nsIGlobalObject* aGlobal,
                       nsAtom* aAnimationName)
    : dom::Animation(aGlobal)
    , mAnimationName(aAnimationName)
    , mIsStylePaused(false)
    , mPauseShouldStick(false)
    , mNeedsNewAnimationIndexWhenRun(false)
    , mPreviousPhase(ComputedTiming::AnimationPhase::Idle)
    , mPreviousIteration(0)
  {
    // We might need to drop this assertion once we add a script-accessible
    // constructor but for animations generated from CSS markup the
    // animation-name should never be empty.
    MOZ_ASSERT(mAnimationName != nsGkAtoms::_empty,
               "animation-name should not be 'none'");
  }

  JSObject* WrapObject(JSContext* aCx,
                       JS::Handle<JSObject*> aGivenProto) override;

  CSSAnimation* AsCSSAnimation() override { return this; }
  const CSSAnimation* AsCSSAnimation() const override { return this; }

  // CSSAnimation interface
  void GetAnimationName(nsString& aRetVal) const
  {
    mAnimationName->ToString(aRetVal);
  }

  nsAtom* AnimationName() const { return mAnimationName; }

  // Animation interface overrides
  virtual Promise* GetReady(ErrorResult& aRv) override;
  virtual void Play(ErrorResult& aRv, LimitBehavior aLimitBehavior) override;
  virtual void Pause(ErrorResult& aRv) override;

  // NOTE: tabbrowser.xml currently relies on the fact that reading the
  // currentTime of a CSSAnimation does *not* flush style (whereas reading the
  // playState does). If CSS Animations 2 specifies that reading currentTime
  // also flushes style we will need to find another way to detect canceled
  // animations in tabbrowser.xml. On the other hand, if CSS Animations 2
  // specifies that reading playState does *not* flush style (and we drop the
  // following override), then we should update tabbrowser.xml to check
  // the playState instead.
  AnimationPlayState PlayStateFromJS() const override;
  bool PendingFromJS() const override;
  void PlayFromJS(ErrorResult& aRv) override;

  void PlayFromStyle();
  void PauseFromStyle();
  void CancelFromStyle() override
  {
    // When an animation is disassociated with style it enters an odd state
    // where its composite order is undefined until it first transitions
    // out of the idle state.
    //
    // Even if the composite order isn't defined we don't want it to be random
    // in case we need to determine the order to dispatch events associated
    // with an animation in this state. To solve this we treat the animation as
    // if it had been added to the end of the global animation list so that
    // its sort order is defined. We'll update this index again once the
    // animation leaves the idle state.
    mAnimationIndex = sNextAnimationIndex++;
    mNeedsNewAnimationIndexWhenRun = true;

    Animation::CancelFromStyle();

    // We need to do this *after* calling CancelFromStyle() since
    // CancelFromStyle might synchronously trigger a cancel event for which
    // we need an owning element to target the event at.
    mOwningElement = OwningElementRef();
  }

  void Tick() override;
  void QueueEvents(const StickyTimeDuration& aActiveTime = StickyTimeDuration());

  bool IsStylePaused() const { return mIsStylePaused; }

  bool HasLowerCompositeOrderThan(const CSSAnimation& aOther) const;

  void SetAnimationIndex(uint64_t aIndex)
  {
    MOZ_ASSERT(IsTiedToMarkup());
    if (IsRelevant() &&
        mAnimationIndex != aIndex) {
      nsNodeUtils::AnimationChanged(this);
      PostUpdate();
    }
    mAnimationIndex = aIndex;
  }

  // Sets the owning element which is used for determining the composite
  // order of CSSAnimation objects generated from CSS markup.
  //
  // @see mOwningElement
  void SetOwningElement(const OwningElementRef& aElement)
  {
    mOwningElement = aElement;
  }
  // True for animations that are generated from CSS markup and continue to
  // reflect changes to that markup.
  bool IsTiedToMarkup() const { return mOwningElement.IsSet(); }

  void MaybeQueueCancelEvent(const StickyTimeDuration& aActiveTime) override {
    QueueEvents(aActiveTime);
  }

protected:
  virtual ~CSSAnimation()
  {
    MOZ_ASSERT(!mOwningElement.IsSet(), "Owning element should be cleared "
                                        "before a CSS animation is destroyed");
  }

  // Animation overrides
  void UpdateTiming(SeekFlag aSeekFlag,
                    SyncNotifyFlag aSyncNotifyFlag) override;

  // Returns the duration from the start of the animation's source effect's
  // active interval to the point where the animation actually begins playback.
  // This is zero unless the animation's source effect has a negative delay in
  // which case it is the absolute value of that delay.
  // This is used for setting the elapsedTime member of CSS AnimationEvents.
  TimeDuration InitialAdvance() const {
    return mEffect ?
           std::max(TimeDuration(), mEffect->SpecifiedTiming().Delay() * -1) :
           TimeDuration();
  }

  RefPtr<nsAtom> mAnimationName;

  // The (pseudo-)element whose computed animation-name refers to this
  // animation (if any).
  //
  // This is used for determining the relative composite order of animations
  // generated from CSS markup.
  //
  // Typically this will be the same as the target element of the keyframe
  // effect associated with this animation. However, it can differ in the
  // following circumstances:
  //
  // a) If script removes or replaces the effect of this animation,
  // b) If this animation is cancelled (e.g. by updating the
  //    animation-name property or removing the owning element from the
  //    document),
  // c) If this object is generated from script using the CSSAnimation
  //    constructor.
  //
  // For (b) and (c) the owning element will return !IsSet().
  OwningElementRef mOwningElement;

  // When combining animation-play-state with play() / pause() the following
  // behavior applies:
  // 1. pause() is sticky and always overrides the underlying
  //    animation-play-state
  // 2. If animation-play-state is 'paused', play() will temporarily override
  //    it until animation-play-state next becomes 'running'.
  // 3. Calls to play() trigger finishing behavior but setting the
  //    animation-play-state to 'running' does not.
  //
  // This leads to five distinct states:
  //
  // A. Running
  // B. Running and temporarily overriding animation-play-state: paused
  // C. Paused and sticky overriding animation-play-state: running
  // D. Paused and sticky overriding animation-play-state: paused
  // E. Paused by animation-play-state
  //
  // C and D may seem redundant but they differ in how to respond to the
  // sequence: call play(), set animation-play-state: paused.
  //
  // C will transition to A then E leaving the animation paused.
  // D will transition to B then B leaving the animation running.
  //
  // A state transition chart is as follows:
  //
  //             A | B | C | D | E
  //   ---------------------------
  //   play()    A | B | A | B | B
  //   pause()   C | D | C | D | D
  //   'running' A | A | C | C | A
  //   'paused'  E | B | D | D | E
  //
  // The base class, Animation already provides a boolean value,
  // mIsPaused which gives us two states. To this we add a further two booleans
  // to represent the states as follows.
  //
  // A. Running
  //    (!mIsPaused; !mIsStylePaused; !mPauseShouldStick)
  // B. Running and temporarily overriding animation-play-state: paused
  //    (!mIsPaused; mIsStylePaused; !mPauseShouldStick)
  // C. Paused and sticky overriding animation-play-state: running
  //    (mIsPaused; !mIsStylePaused; mPauseShouldStick)
  // D. Paused and sticky overriding animation-play-state: paused
  //    (mIsPaused; mIsStylePaused; mPauseShouldStick)
  // E. Paused by animation-play-state
  //    (mIsPaused; mIsStylePaused; !mPauseShouldStick)
  //
  // (That leaves 3 combinations of the boolean values that we never set because
  // they don't represent valid states.)
  bool mIsStylePaused;
  bool mPauseShouldStick;

  // When true, indicates that when this animation next leaves the idle state,
  // its animation index should be updated.
  bool mNeedsNewAnimationIndexWhenRun;

  // Phase and current iteration from the previous time we queued events.
  // This is used to determine what new events to dispatch.
  ComputedTiming::AnimationPhase mPreviousPhase;
  uint64_t mPreviousIteration;
};

} /* namespace dom */

template <>
struct AnimationTypeTraits<dom::CSSAnimation>
{
  static nsAtom* ElementPropertyAtom()
  {
    return nsGkAtoms::animationsProperty;
  }
  static nsAtom* BeforePropertyAtom()
  {
    return nsGkAtoms::animationsOfBeforeProperty;
  }
  static nsAtom* AfterPropertyAtom()
  {
    return nsGkAtoms::animationsOfAfterProperty;
  }
};

} /* namespace mozilla */

class nsAnimationManager final
  : public mozilla::CommonAnimationManager<mozilla::dom::CSSAnimation>
{
public:
  explicit nsAnimationManager(nsPresContext *aPresContext)
    : mozilla::CommonAnimationManager<mozilla::dom::CSSAnimation>(aPresContext)
  {
  }

  typedef mozilla::AnimationCollection<mozilla::dom::CSSAnimation>
    CSSAnimationCollection;
  typedef nsTArray<RefPtr<mozilla::dom::CSSAnimation>>
    OwningCSSAnimationPtrArray;

  ~nsAnimationManager() override = default;

  /**
   * This function does the same thing as the above UpdateAnimations()
   * but with servo's computed values.
   */
  void UpdateAnimations(
    mozilla::dom::Element* aElement,
    mozilla::CSSPseudoElementType aPseudoType,
    const mozilla::ComputedStyle* aComputedValues);


  // Utility function to walk through |aIter| to find the Keyframe with
  // matching offset and timing function but stopping as soon as the offset
  // differs from |aOffset| (i.e. it assumes a sorted iterator).
  //
  // If a matching Keyframe is found,
  //   Returns true and sets |aIndex| to the index of the matching Keyframe
  //   within |aIter|.
  //
  // If no matching Keyframe is found,
  //   Returns false and sets |aIndex| to the index in the iterator of the
  //   first Keyframe with an offset differing to |aOffset| or, if the end
  //   of the iterator is reached, sets |aIndex| to the index after the last
  //   Keyframe.
  template <class IterType, class TimingFunctionType>
  static bool FindMatchingKeyframe(
    IterType&& aIter,
    double aOffset,
    const TimingFunctionType& aTimingFunctionToMatch,
    size_t& aIndex)
  {
    aIndex = 0;
    for (mozilla::Keyframe& keyframe : aIter) {
      if (keyframe.mOffset.value() != aOffset) {
        break;
      }
      if (keyframe.mTimingFunction == aTimingFunctionToMatch) {
        return true;
      }
      ++aIndex;
    }
    return false;
  }

  bool AnimationMayBeReferenced(nsAtom* aName) const
  {
    return mMaybeReferencedAnimations.Contains(aName);
  }

private:
  // This includes all animation names referenced regardless of whether a
  // corresponding `@keyframes` rule is available.
  //
  // It may contain names which are no longer referenced, but it should always
  // contain names which are currently referenced, so that it is usable for
  // style invalidation.
  nsTHashtable<nsRefPtrHashKey<nsAtom>> mMaybeReferencedAnimations;

  void DoUpdateAnimations(
    const mozilla::NonOwningAnimationTarget& aTarget,
    const nsStyleDisplay& aStyleDisplay,
    ServoCSSAnimationBuilder& aBuilder);
};

#endif /* !defined(nsAnimationManager_h_) */