Bug 1203009 part 1 - Rename sequence number to animation index; r=heycam

The Web Animations specification has replaced the term "sequence number" with
references to a global animation list. This patch applies similar naming
to our animation structures.

dom/animation/Animation.cpp

@@ -22,7 +22,7 @@ namespace mozilla {
 namespace dom {
 
 // Static members
-uint64_t Animation::sNextSequenceNum = 0;
+uint64_t Animation::sNextAnimationIndex = 0;
 
 NS_IMPL_CYCLE_COLLECTION_INHERITED(Animation, DOMEventTargetHelper,
                                    mTimeline,
@@ -518,14 +518,14 @@ bool
 Animation::HasLowerCompositeOrderThan(const Animation& aOther) const
 {
   // We only ever sort non-idle animations so we don't ever expect
-  // mSequenceNum to be set to kUnsequenced
-  MOZ_ASSERT(mSequenceNum != kUnsequenced &&
-             aOther.mSequenceNum != kUnsequenced,
+  // mAnimationIndex to be set to kNoIndex
+  MOZ_ASSERT(mAnimationIndex != kNoIndex &&
+             aOther.mAnimationIndex != kNoIndex,
              "Animations to compare should not be idle");
-  MOZ_ASSERT(mSequenceNum != aOther.mSequenceNum || &aOther == this,
-             "Sequence numbers should be unique");
+  MOZ_ASSERT(mAnimationIndex != aOther.mAnimationIndex || &aOther == this,
+             "Animation indices should be unique");
 
-  return mSequenceNum < aOther.mSequenceNum;
+  return mAnimationIndex < aOther.mAnimationIndex;
 }
 
 bool
@@ -842,13 +842,13 @@ Animation::PauseAt(const TimeDuration& aReadyTime)
 void
 Animation::UpdateTiming(SeekFlag aSeekFlag, SyncNotifyFlag aSyncNotifyFlag)
 {
-  // Update the sequence number each time we transition in or out of the
+  // Update the animation index each time we transition in or out of the
   // idle state
   if (!IsUsingCustomCompositeOrder()) {
     if (PlayState() == AnimationPlayState::Idle) {
-      mSequenceNum = kUnsequenced;
-    } else if (mSequenceNum == kUnsequenced) {
-      mSequenceNum = sNextSequenceNum++;
+      mAnimationIndex = kNoIndex;
+    } else if (mAnimationIndex == kNoIndex) {
+      mAnimationIndex = sNextAnimationIndex++;
     }
   }
 

dom/animation/Animation.h

@@ -57,7 +57,7 @@ public:
     : DOMEventTargetHelper(aGlobal)
     , mPlaybackRate(1.0)
     , mPendingState(PendingState::NotPending)
-    , mSequenceNum(kUnsequenced)
+    , mAnimationIndex(kNoIndex)
     , mIsRunningOnCompositor(false)
     , mFinishedAtLastComposeStyle(false)
     , mIsRelevant(false)
@@ -405,13 +405,17 @@ protected:
   enum class PendingState { NotPending, PlayPending, PausePending };
   PendingState mPendingState;
 
-  static uint64_t sNextSequenceNum;
-  static const uint64_t kUnsequenced = UINT64_MAX;
+  static uint64_t sNextAnimationIndex;
+  static const uint64_t kNoIndex = UINT64_MAX;
 
-  // The sequence number assigned to this animation. This is kUnsequenced
-  // while the animation is in the idle state and is updated each time
-  // the animation transitions out of the idle state.
-  uint64_t mSequenceNum;
+  // The relative position of this animation within the global animation list.
+  // This is kNoIndex while the animation is in the idle state and is updated
+  // each time the animation transitions out of the idle state.
+  //
+  // Note that subclasses such as CSSTransition and CSSAnimation may repurpose
+  // this member to implement their own brand of sorting. As a result, it is
+  // possible for two different objects to have the same index.
+  uint64_t mAnimationIndex;
 
   bool mIsRunningOnCompositor;
   bool mFinishedAtLastComposeStyle;

layout/style/nsAnimationManager.cpp

@@ -162,7 +162,7 @@ CSSAnimation::HasLowerCompositeOrderThan(const Animation& aOther) const
   }
 
   // 4. (Same element and pseudo): Sort by position in animation-name
-  return mSequenceNum < otherAnimation->mSequenceNum;
+  return mAnimationIndex < otherAnimation->mAnimationIndex;
 }
 
 void

layout/style/nsAnimationManager.h

@@ -98,7 +98,7 @@ public:
   {
     mOwningElement = OwningElementRef();
     Animation::CancelFromStyle();
-    MOZ_ASSERT(mSequenceNum == kUnsequenced);
+    MOZ_ASSERT(mAnimationIndex == kNoIndex);
   }
 
   void Tick() override;
@@ -116,13 +116,13 @@ public:
   void SetAnimationIndex(uint64_t aIndex)
   {
     MOZ_ASSERT(IsUsingCustomCompositeOrder());
-    mSequenceNum = aIndex;
+    mAnimationIndex = aIndex;
   }
   void CopyAnimationIndex(const CSSAnimation& aOther)
   {
     MOZ_ASSERT(IsUsingCustomCompositeOrder() &&
                aOther.IsUsingCustomCompositeOrder());
-    mSequenceNum = aOther.mSequenceNum;
+    mAnimationIndex = aOther.mAnimationIndex;
   }
 
   // Returns the element or pseudo-element whose animation-name property

layout/style/nsTransitionManager.cpp

@@ -205,8 +205,8 @@ CSSTransition::HasLowerCompositeOrderThan(const Animation& aOther) const
   }
 
   // 4. (Same element and pseudo): Sort by transition generation
-  if (mSequenceNum != otherTransition->mSequenceNum) {
-    return mSequenceNum < otherTransition->mSequenceNum;
+  if (mAnimationIndex != otherTransition->mAnimationIndex) {
+    return mAnimationIndex < otherTransition->mAnimationIndex;
   }
 
   // 5. (Same transition generation): Sort by transition property

layout/style/nsTransitionManager.h

@@ -115,7 +115,7 @@ public:
   {
     mOwningElement = OwningElementRef();
     Animation::CancelFromStyle();
-    MOZ_ASSERT(mSequenceNum == kUnsequenced);
+    MOZ_ASSERT(mAnimationIndex == kNoIndex);
   }
 
   void Tick() override;
@@ -131,7 +131,7 @@ public:
   void SetCreationSequence(uint64_t aIndex)
   {
     MOZ_ASSERT(IsUsingCustomCompositeOrder());
-    mSequenceNum = aIndex;
+    mAnimationIndex = aIndex;
   }
 
   // Returns the element or pseudo-element whose transition-property property