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 NS_SMILANIMATIONCONTROLLER_H_
8 #define NS_SMILANIMATIONCONTROLLER_H_
9 
10 #include "mozilla/Attributes.h"
11 #include "nsAutoPtr.h"
12 #include "nsCOMPtr.h"
13 #include "nsTArray.h"
14 #include "nsITimer.h"
15 #include "nsTHashtable.h"
16 #include "nsHashKeys.h"
17 #include "nsSMILTimeContainer.h"
18 #include "nsSMILCompositorTable.h"
19 #include "nsSMILMilestone.h"
20 #include "nsRefreshDriver.h"
21 
22 struct nsSMILTargetIdentifier;
23 class nsIDocument;
24 
25 namespace mozilla {
26 class RestyleTracker;
27 namespace dom {
28 class SVGAnimationElement;
29 } // namespace dom
30 } // namespace mozilla
31 
32 //----------------------------------------------------------------------
33 // nsSMILAnimationController
34 //
35 // The animation controller maintains the animation timer and determines the
36 // sample times and sample rate for all SMIL animations in a document. There is
37 // at most one animation controller per nsDocument so that frame-rate tuning can
38 // be performed at a document-level.
39 //
40 // The animation controller can contain many child time containers (timed
41 // document root objects) which may correspond to SVG document fragments within
42 // a compound document. These time containers can be paused individually or
43 // here, at the document level.
44 //
45 class nsSMILAnimationController final : public nsSMILTimeContainer,
46                                         public nsARefreshObserver
47 {
48 public:
49   explicit nsSMILAnimationController(nsIDocument* aDoc);
50 
51   // Clears mDocument pointer. (Called by our nsIDocument when it's going away)
52   void Disconnect();
53 
54   // nsSMILContainer
55   virtual void Pause(uint32_t aType) override;
56   virtual void Resume(uint32_t aType) override;
57   virtual nsSMILTime GetParentTime() const override;
58 
59   // nsARefreshObserver
60   NS_IMETHOD_(MozExternalRefCountType) AddRef() override;
61   NS_IMETHOD_(MozExternalRefCountType) Release() override;
62 
63   virtual void WillRefresh(mozilla::TimeStamp aTime) override;
64 
65   // Methods for registering and enumerating animation elements
66   void RegisterAnimationElement(mozilla::dom::SVGAnimationElement* aAnimationElement);
67   void UnregisterAnimationElement(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.
Resample()73   void Resample() { DoSample(false); }
74 
SetResampleNeeded()75   void SetResampleNeeded()
76   {
77     if (!mRunningSample && !mResampleNeeded) {
78       FlagDocumentNeedsFlush();
79       mResampleNeeded = true;
80     }
81   }
82 
83   // This will flush pending style changes for the document.
FlushResampleRequests()84   void FlushResampleRequests()
85   {
86     if (!mResampleNeeded)
87       return;
88 
89     Resample();
90   }
91 
92   // Methods for handling page transitions
93   void OnPageShow();
94   void OnPageHide();
95 
96   // Methods for supporting cycle-collection
97   void Traverse(nsCycleCollectionTraversalCallback* aCallback);
98   void Unlink();
99 
100   // Methods for relaying the availability of the refresh driver
101   void NotifyRefreshDriverCreated(nsRefreshDriver* aRefreshDriver);
102   void NotifyRefreshDriverDestroying(nsRefreshDriver* aRefreshDriver);
103 
104   // Helper to check if we have any animation elements at all
HasRegisteredAnimations()105   bool HasRegisteredAnimations() const
106   {
107     return mAnimationElementTable.Count() != 0;
108   }
109 
110   void AddStyleUpdatesTo(mozilla::RestyleTracker& aTracker);
MightHavePendingStyleUpdates()111   bool MightHavePendingStyleUpdates() const
112   {
113     return mMightHavePendingStyleUpdates;
114   }
115 
116 protected:
117   ~nsSMILAnimationController();
118 
119   // Typedefs
120   typedef nsPtrHashKey<nsSMILTimeContainer> TimeContainerPtrKey;
121   typedef nsTHashtable<TimeContainerPtrKey> TimeContainerHashtable;
122   typedef nsPtrHashKey<mozilla::dom::SVGAnimationElement> AnimationElementPtrKey;
123   typedef nsTHashtable<AnimationElementPtrKey> AnimationElementHashtable;
124 
125   // Returns mDocument's refresh driver, if it's got one.
126   nsRefreshDriver* GetRefreshDriver();
127 
128   // Methods for controlling whether we're sampling
129   void StartSampling(nsRefreshDriver* aRefreshDriver);
130   void StopSampling(nsRefreshDriver* aRefreshDriver);
131 
132   // Wrapper for StartSampling that defers if no animations are registered.
133   void MaybeStartSampling(nsRefreshDriver* aRefreshDriver);
134 
135   // Sample-related callbacks and implementation helpers
136   virtual void DoSample() override;
137   void DoSample(bool aSkipUnchangedContainers);
138 
139   void RewindElements();
140 
141   void DoMilestoneSamples();
142 
143   static void SampleTimedElement(mozilla::dom::SVGAnimationElement* aElement,
144                                  TimeContainerHashtable* aActiveContainers);
145 
146   static void AddAnimationToCompositorTable(
147       mozilla::dom::SVGAnimationElement* aElement,
148       nsSMILCompositorTable* aCompositorTable,
149       bool& aStyleFlushNeeded);
150 
151   static bool GetTargetIdentifierForAnimation(
152       mozilla::dom::SVGAnimationElement* aAnimElem, nsSMILTargetIdentifier& aResult);
153 
154   // Methods for adding/removing time containers
155   virtual nsresult AddChild(nsSMILTimeContainer& aChild) override;
156   virtual void     RemoveChild(nsSMILTimeContainer& aChild) override;
157 
158   void FlagDocumentNeedsFlush();
159 
160   // Members
161   nsAutoRefCnt mRefCnt;
162   NS_DECL_OWNINGTHREAD
163 
164   AnimationElementHashtable  mAnimationElementTable;
165   TimeContainerHashtable     mChildContainerTable;
166   mozilla::TimeStamp         mCurrentSampleTime;
167   mozilla::TimeStamp         mStartTime;
168 
169   // Average time between samples from the refresh driver. This is used to
170   // detect large unexpected gaps between samples such as can occur when the
171   // computer sleeps. The nature of the SMIL model means that catching up these
172   // large gaps can be expensive as, for example, many events may need to be
173   // dispatched for the intervening time when no samples were received.
174   //
175   // In such cases, we ignore the intervening gap and continue sampling from
176   // when we were expecting the next sample to arrive.
177   //
178   // Note that we only do this for SMIL and not CSS transitions (which doesn't
179   // have so much work to do to catch up) nor scripted animations (which expect
180   // animation time to follow real time).
181   //
182   // This behaviour does not affect pausing (since we're not *expecting* any
183   // samples then) nor seeking (where the SMIL model behaves somewhat
184   // differently such as not dispatching events).
185   nsSMILTime                 mAvgTimeBetweenSamples;
186 
187   bool                       mResampleNeeded;
188   // If we're told to start sampling but there are no animation elements we just
189   // record the time, set the following flag, and then wait until we have an
190   // animation element. Then we'll reset this flag and actually start sampling.
191   bool                       mDeferredStartSampling;
192   bool                       mRunningSample;
193 
194   // Are we registered with our document's refresh driver?
195   bool                       mRegisteredWithRefreshDriver;
196 
197   // Have we updated animated values without adding them to the restyle tracker?
198   bool                       mMightHavePendingStyleUpdates;
199 
200   // Store raw ptr to mDocument.  It owns the controller, so controller
201   // shouldn't outlive it
202   nsIDocument* mDocument;
203 
204   // Contains compositors used in our last sample.  We keep this around
205   // so we can detect when an element/attribute used to be animated,
206   // but isn't anymore for some reason. (e.g. if its <animate> element is
207   // removed or retargeted)
208   nsAutoPtr<nsSMILCompositorTable> mLastCompositorTable;
209 };
210 
211 #endif // NS_SMILANIMATIONCONTROLLER_H_
212