dom/smil/SMILAnimationController.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef DOM_SMIL_SMILANIMATIONCONTROLLER_H_
   8 #define DOM_SMIL_SMILANIMATIONCONTROLLER_H_
   9
  10 #include "mozilla/Attributes.h"
  11 #include "mozilla/SMILCompositorTable.h"
  12 #include "mozilla/SMILMilestone.h"
  13 #include "mozilla/SMILTimeContainer.h"
  14 #include "mozilla/UniquePtr.h"
  15 #include "nsCOMPtr.h"
  16 #include "nsTArray.h"
  17 #include "nsTHashtable.h"
  18 #include "nsHashKeys.h"
  19 #include "nsRefreshObservers.h"
  20
  21 class nsRefreshDriver;
  22
  23 namespace mozilla {
  24 struct SMILTargetIdentifier;
  25 namespace dom {
  26 class Element;
  27 class SVGAnimationElement;
  28 }  // namespace dom
  29
  30 //----------------------------------------------------------------------
  31 // SMILAnimationController
  32 //
  33 // The animation controller maintains the animation timer and determines the
  34 // sample times and sample rate for all SMIL animations in a document. There is
  35 // at most one animation controller per document so that frame-rate tuning can
  36 // be performed at a document-level.
  37 //
  38 // The animation controller can contain many child time containers (timed
  39 // document root objects) which may correspond to SVG document fragments within
  40 // a compound document. These time containers can be paused individually or
  41 // here, at the document level.
  42 //
  43 class SMILAnimationController final : public SMILTimeContainer,
  44                                       public nsARefreshObserver {
  45  public:
  46   explicit SMILAnimationController(mozilla::dom::Document* aDoc);
  47
  48   // Clears mDocument pointer. (Called by our mozilla::dom::Document when it's
  49   // going away)
  50   void Disconnect();
  51
  52   // SMILContainer
  53   virtual void Pause(uint32_t aType) override;
  54   virtual void Resume(uint32_t aType) override;
  55   virtual SMILTime GetParentTime() const override;
  56
  57   // nsARefreshObserver
  58   NS_IMETHOD_(MozExternalRefCountType) AddRef() override;
  59   NS_IMETHOD_(MozExternalRefCountType) Release() override;
  60
  61   virtual void WillRefresh(mozilla::TimeStamp aTime) override;
  62
  63   // Methods for registering and enumerating animation elements
  64   void RegisterAnimationElement(
  65       mozilla::dom::SVGAnimationElement* aAnimationElement);
  66   void UnregisterAnimationElement(
  67       mozilla::dom::SVGAnimationElement* aAnimationElement);
  68
  69   // Methods for resampling all animations
  70   // (A resample performs the same operations as a sample but doesn't advance
  71   // the current time and doesn't check if the container is paused)
  72   // This will flush pending style changes for the document.
  73   void Resample() { DoSample(false); }
  74
  75   void SetResampleNeeded() {
  76     if (!mRunningSample && !mResampleNeeded) {
  77       FlagDocumentNeedsFlush();
  78       mResampleNeeded = true;
  79     }
  80   }
  81
  82   // This will flush pending style changes for the document.
  83   void FlushResampleRequests() {
  84     if (!mResampleNeeded) return;
  85
  86     Resample();
  87   }
  88
  89   // Methods for handling page transitions
  90   void OnPageShow();
  91   void OnPageHide();
  92
  93   // Methods for supporting cycle-collection
  94   void Traverse(nsCycleCollectionTraversalCallback* aCallback);
  95   void Unlink();
  96
  97   // Methods for relaying the availability of the refresh driver
  98   void NotifyRefreshDriverCreated(nsRefreshDriver* aRefreshDriver);
  99   void NotifyRefreshDriverDestroying(nsRefreshDriver* aRefreshDriver);
 100
 101   // Helper to check if we have any animation elements at all
 102   bool HasRegisteredAnimations() const {
 103     return mAnimationElementTable.Count() != 0;
 104   }
 105
 106   bool MightHavePendingStyleUpdates() const {
 107     return mMightHavePendingStyleUpdates;
 108   }
 109
 110   bool PreTraverse();
 111   bool PreTraverseInSubtree(mozilla::dom::Element* aRoot);
 112
 113  protected:
 114   ~SMILAnimationController();
 115
 116   // alias declarations
 117   using TimeContainerPtrKey = nsPtrHashKey<SMILTimeContainer>;
 118   using TimeContainerHashtable = nsTHashtable<TimeContainerPtrKey>;
 119   using AnimationElementPtrKey = nsPtrHashKey<dom::SVGAnimationElement>;
 120   using AnimationElementHashtable = nsTHashtable<AnimationElementPtrKey>;
 121
 122   // Returns mDocument's refresh driver, if it's got one.
 123   nsRefreshDriver* GetRefreshDriver();
 124
 125   // Methods for controlling whether we're sampling
 126   void StartSampling(nsRefreshDriver* aRefreshDriver);
 127   void StopSampling(nsRefreshDriver* aRefreshDriver);
 128
 129   // Wrapper for StartSampling that defers if no animations are registered.
 130   void MaybeStartSampling(nsRefreshDriver* aRefreshDriver);
 131
 132   // Sample-related callbacks and implementation helpers
 133   virtual void DoSample() override;
 134   void DoSample(bool aSkipUnchangedContainers);
 135
 136   void RewindElements();
 137
 138   void DoMilestoneSamples();
 139
 140   static void SampleTimedElement(mozilla::dom::SVGAnimationElement* aElement,
 141                                  TimeContainerHashtable* aActiveContainers);
 142
 143   static void AddAnimationToCompositorTable(
 144       mozilla::dom::SVGAnimationElement* aElement,
 145       SMILCompositorTable* aCompositorTable, bool& aStyleFlushNeeded);
 146
 147   static bool GetTargetIdentifierForAnimation(
 148       mozilla::dom::SVGAnimationElement* aAnimElem,
 149       SMILTargetIdentifier& aResult);
 150
 151   // Methods for adding/removing time containers
 152   virtual nsresult AddChild(SMILTimeContainer& aChild) override;
 153   virtual void RemoveChild(SMILTimeContainer& aChild) override;
 154
 155   void FlagDocumentNeedsFlush();
 156
 157   // Members
 158   nsAutoRefCnt mRefCnt;
 159   NS_DECL_OWNINGTHREAD
 160
 161   AnimationElementHashtable mAnimationElementTable;
 162   TimeContainerHashtable mChildContainerTable;
 163   mozilla::TimeStamp mCurrentSampleTime;
 164   mozilla::TimeStamp mStartTime;
 165
 166   // Average time between samples from the refresh driver. This is used to
 167   // detect large unexpected gaps between samples such as can occur when the
 168   // computer sleeps. The nature of the SMIL model means that catching up these
 169   // large gaps can be expensive as, for example, many events may need to be
 170   // dispatched for the intervening time when no samples were received.
 171   //
 172   // In such cases, we ignore the intervening gap and continue sampling from
 173   // when we were expecting the next sample to arrive.
 174   //
 175   // Note that we only do this for SMIL and not CSS transitions (which doesn't
 176   // have so much work to do to catch up) nor scripted animations (which expect
 177   // animation time to follow real time).
 178   //
 179   // This behaviour does not affect pausing (since we're not *expecting* any
 180   // samples then) nor seeking (where the SMIL model behaves somewhat
 181   // differently such as not dispatching events).
 182   SMILTime mAvgTimeBetweenSamples;
 183
 184   bool mResampleNeeded;
 185   // If we're told to start sampling but there are no animation elements we just
 186   // record the time, set the following flag, and then wait until we have an
 187   // animation element. Then we'll reset this flag and actually start sampling.
 188   bool mDeferredStartSampling;
 189   bool mRunningSample;
 190
 191   // Are we registered with our document's refresh driver?
 192   bool mRegisteredWithRefreshDriver;
 193
 194   // Have we updated animated values without adding them to the restyle tracker?
 195   bool mMightHavePendingStyleUpdates;
 196
 197   // Store raw ptr to mDocument.  It owns the controller, so controller
 198   // shouldn't outlive it
 199   mozilla::dom::Document* mDocument;
 200
 201   // Contains compositors used in our last sample.  We keep this around
 202   // so we can detect when an element/attribute used to be animated,
 203   // but isn't anymore for some reason. (e.g. if its <animate> element is
 204   // removed or retargeted)
 205   UniquePtr<SMILCompositorTable> mLastCompositorTable;
 206 };
 207
 208 }  // namespace mozilla
 209
 210 #endif  // DOM_SMIL_SMILANIMATIONCONTROLLER_H_