author Boris Chiou <>
Fri, 01 Mar 2019 21:13:05 +0000
changeset 519915 c05471f233f32996e77e8aa4476afb02630cd9c0
parent 519914 3daab28714966b7ad75f6ae4b5b46cb7c4e7da3e
child 523577 296f63c52362834aef096a7e91c68781f9a19325
permissions -rw-r--r--
Bug 1526850 - Part 3: Use DisplayItemType as the input of AddTransitionsAndAnimationsToLayer. r=hiro Transform display item may have multiple properties, so it's better to use display item type as the input. Also, factor some code out of AddAnimationsForProperty, so we can easier to extend this for multiple properties. We will pass a list of layers::Animation to the compositor thread. In this list, the animations belonging to the same property are grouped together, so we can easily separate the animations by property and sample the animations for each property on the compositor thread. (Will do this in Bug 1425837.) Depends on D19628 Differential Revision:

/* -*- 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 */

#ifndef mozilla_EffectCompositor_h
#define mozilla_EffectCompositor_h

#include "mozilla/AnimationPerformanceWarning.h"
#include "mozilla/EnumeratedArray.h"
#include "mozilla/Maybe.h"
#include "mozilla/OwningNonNull.h"
#include "mozilla/PseudoElementHashEntry.h"
#include "mozilla/RefPtr.h"
#include "mozilla/ServoTypes.h"
#include "nsCSSPropertyID.h"
#include "nsCycleCollectionParticipant.h"
#include "nsDataHashtable.h"
#include "nsTArray.h"

class nsCSSPropertyIDSet;
class nsAtom;
class nsIFrame;
class nsPresContext;
enum class DisplayItemType : uint32_t;
struct RawServoAnimationValueMap;
typedef RawServoAnimationValueMap* RawServoAnimationValueMapBorrowedMut;

namespace mozilla {

class ComputedStyle;
class EffectSet;
class RestyleTracker;
class StyleAnimationValue;
struct AnimationProperty;
struct NonOwningAnimationTarget;

namespace dom {
class Animation;
class Element;
}  // namespace dom

class EffectCompositor {
  explicit EffectCompositor(nsPresContext* aPresContext)
      : mPresContext(aPresContext) {}


  void Disconnect() { mPresContext = nullptr; }

  // Animations can be applied at two different levels in the CSS cascade:
  enum class CascadeLevel : uint32_t {
    // The animations sheet (CSS animations, script-generated animations,
    // and CSS transitions that are no longer tied to CSS markup)
    Animations = 0,
    // The transitions sheet (CSS transitions that are tied to CSS markup)
    Transitions = 1
  // We don't define this as part of CascadeLevel as then we'd have to add
  // explicit checks for the Count enum value everywhere CascadeLevel is used.
  static const size_t kCascadeLevelCount =
      static_cast<size_t>(CascadeLevel::Transitions) + 1;

  // NOTE: This can return null after Disconnect().
  nsPresContext* PresContext() const { return mPresContext; }

  enum class RestyleType {
    // Animation style has changed but the compositor is applying the same
    // change so we might be able to defer updating the main thread until it
    // becomes necessary.
    // Animation style has changed and needs to be updated on the main thread.
    // Animation style has changed and needs to be updated on the main thread
    // as well as forcing animations on layers to be updated.
    // This is needed in cases such as when an animation becomes paused or has
    // its playback rate changed. In such cases, although the computed style
    // and refresh driver time might not change, we still need to ensure the
    // corresponding animations on layers are updated to reflect the new
    // configuration of the animation.

  // Notifies the compositor that the animation rule for the specified
  // (pseudo-)element at the specified cascade level needs to be updated.
  // The specified steps taken to update the animation rule depend on
  // |aRestyleType| whose values are described above.
  void RequestRestyle(dom::Element* aElement, PseudoStyleType aPseudoType,
                      RestyleType aRestyleType, CascadeLevel aCascadeLevel);

  // Schedule an animation restyle. This is called automatically by
  // RequestRestyle when necessary. However, it is exposed here since we also
  // need to perform this step when triggering transitions *without* also
  // invalidating the animation style rule (which RequestRestyle would do).
  void PostRestyleForAnimation(dom::Element* aElement,
                               PseudoStyleType aPseudoType,
                               CascadeLevel aCascadeLevel);

  // Posts an animation restyle for any elements whose animation style rule
  // is out of date but for which an animation restyle has not yet been
  // posted because updates on the main thread are throttled.
  void PostRestyleForThrottledAnimations();

  // Clear all pending restyle requests for the given (pseudo-) element (and its
  // ::before and ::after elements if the given element is not pseudo).
  void ClearRestyleRequestsFor(dom::Element* aElement);

  // Called when computed style on the specified (pseudo-) element might
  // have changed so that any context-sensitive values stored within
  // animation effects (e.g. em-based endpoints used in keyframe effects)
  // can be re-resolved to computed values.
  void UpdateEffectProperties(const ComputedStyle* aStyle,
                              dom::Element* aElement,
                              PseudoStyleType aPseudoType);

  // Get animation rule for stylo. This is an equivalent of GetAnimationRule
  // and will be called from servo side.
  // The animation rule is stored in |RawServoAnimationValueMapBorrowed|.
  // We need to be careful while doing any modification because it may cause
  // some thread-safe issues.
  bool GetServoAnimationRule(
      const dom::Element* aElement, PseudoStyleType aPseudoType,
      CascadeLevel aCascadeLevel,
      RawServoAnimationValueMapBorrowedMut aAnimationValues);

  bool HasPendingStyleUpdates() const;

  static bool HasAnimationsForCompositor(const nsIFrame* aFrame,
                                         DisplayItemType aType);

  static nsTArray<RefPtr<dom::Animation>> GetAnimationsForCompositor(
      const nsIFrame* aFrame, const nsCSSPropertyIDSet& aPropertySet);

  static void ClearIsRunningOnCompositor(const nsIFrame* aFrame,
                                         DisplayItemType aType);

  // Update animation cascade results for the specified (pseudo-)element
  // but only if we have marked the cascade as needing an update due a
  // the change in the set of effects or a change in one of the effects'
  // "in effect" state.
  // This method does NOT detect if other styles that apply above the
  // animation level of the cascade have changed.
  static void MaybeUpdateCascadeResults(dom::Element* aElement,
                                        PseudoStyleType aPseudoType);

  // Update the mPropertiesWithImportantRules and
  // mPropertiesForAnimationsLevel members of the given EffectSet, and also
  // request any restyles required by changes to the cascade result.
  // NOTE: This can be expensive so we should only call it if styles that apply
  // above the animation level of the cascade might have changed. For all
  // other cases we should call MaybeUpdateCascadeResults.
  // This is typically reserved for internal callers but is public here since
  // when we detect changes to the cascade on the Servo side we can't call
  // MarkCascadeNeedsUpdate during the traversal so instead we call this as part
  // of a follow-up sequential task.
  static void UpdateCascadeResults(EffectSet& aEffectSet,
                                   dom::Element* aElement,
                                   PseudoStyleType aPseudoType);

  // Helper to fetch the corresponding element and pseudo-type from a frame.
  // For frames corresponding to pseudo-elements, the returned element is the
  // element on which we store the animations (i.e. the EffectSet and/or
  // AnimationCollection), *not* the generated content.
  // Returns an empty result when a suitable element cannot be found including
  // when the frame represents a pseudo-element on which we do not support
  // animations.
  static Maybe<NonOwningAnimationTarget> GetAnimationElementAndPseudoForFrame(
      const nsIFrame* aFrame);

  // Associates a performance warning with effects on |aFrame| that animates
  // |aProperty|.
  static void SetPerformanceWarning(
      const nsIFrame* aFrame, nsCSSPropertyID aProperty,
      const AnimationPerformanceWarning& aWarning);

  // Do a bunch of stuff that we should avoid doing during the parallel
  // traversal (e.g. changing member variables) for all elements that we expect
  // to restyle on the next traversal.
  // Returns true if there are elements needing a restyle for animation.
  bool PreTraverse(ServoTraversalFlags aFlags);

  // Similar to the above but only for the (pseudo-)element.
  bool PreTraverse(dom::Element* aElement, PseudoStyleType aPseudoType);

  // Similar to the above but for all elements in the subtree rooted
  // at aElement.
  bool PreTraverseInSubtree(ServoTraversalFlags aFlags, dom::Element* aRoot);

  // Returns the target element for restyling.
  // If |aPseudoType| is ::after or ::before, returns the generated content
  // element of which |aElement| is the parent. If |aPseudoType| is any other
  // pseudo type (other than PseudoStyleType::NotPseudo) returns nullptr.
  // Otherwise, returns |aElement|.
  static dom::Element* GetElementToRestyle(dom::Element* aElement,
                                           PseudoStyleType aPseudoType);

  // Returns true if any type of compositor animations on |aFrame| allow
  // runnning on the compositor.
  // Sets the reason in |aWarning| if the result is false.
  static bool AllowCompositorAnimationsOnFrame(
      const nsIFrame* aFrame,
      AnimationPerformanceWarning::Type& aWarning /* out */);

  ~EffectCompositor() = default;

  // Get the properties in |aEffectSet| that we are able to animate on the
  // compositor but which are also specified at a higher level in the cascade
  // than the animations level.
  static nsCSSPropertyIDSet GetOverriddenProperties(
      EffectSet& aEffectSet, dom::Element* aElement,
      PseudoStyleType aPseudoType);

  static nsPresContext* GetPresContext(dom::Element* aElement);

  nsPresContext* mPresContext;

  // Elements with a pending animation restyle. The associated bool value is
  // true if a pending animation restyle has also been dispatched. For
  // animations that can be throttled, we will add an entry to the hashtable to
  // indicate that the style rule on the element is out of date but without
  // posting a restyle to update it.
  EnumeratedArray<CascadeLevel, CascadeLevel(kCascadeLevelCount),
                  nsDataHashtable<PseudoElementHashEntry, bool>>

  bool mIsInPreTraverse = false;

}  // namespace mozilla

#endif  // mozilla_EffectCompositor_h