Bug 1209405 - Part 3: Save updating style. r=birtles

MozReview-Commit-ID: FAWfIeXrLki

dom/smil/nsSMILAnimationController.cpp

@@ -319,12 +319,13 @@ nsSMILAnimationController::DoSample(bool aSkipUnchangedContainers)
     return;
   }
 
+  bool isStyleFlushNeeded = mResampleNeeded;
   mResampleNeeded = false;
   // Set running sample flag -- do this before flushing styles so that when we
   // flush styles we don't end up requesting extra samples
   AutoRestore<bool> autoRestoreRunningSample(mRunningSample);
   mRunningSample = true;
-  
+
   // STEP 1: Bring model up to date
   // (i)  Rewind elements where necessary
   // (ii) Run milestone samples
@@ -378,7 +379,9 @@ nsSMILAnimationController::DoSample(bool aSkipUnchangedContainers)
   for (auto iter = mAnimationElementTable.Iter(); !iter.Done(); iter.Next()) {
     SVGAnimationElement* animElem = iter.Get()->GetKey();
     SampleTimedElement(animElem, &activeContainers);
-    AddAnimationToCompositorTable(animElem, currentCompositorTable);
+    AddAnimationToCompositorTable(animElem,
+                                  currentCompositorTable,
+                                  isStyleFlushNeeded);
   }
   activeContainers.Clear();
 
@@ -422,9 +425,11 @@ nsSMILAnimationController::DoSample(bool aSkipUnchangedContainers)
   }
 
   nsCOMPtr<nsIDocument> kungFuDeathGrip(mDocument);  // keeps 'this' alive too
-  mDocument->FlushPendingNotifications(Flush_Style);
+  if (isStyleFlushNeeded) {
+    mDocument->FlushPendingNotifications(Flush_Style);
+  }
 
-  // WARNING: 
+  // WARNING:
   // WARNING: the above flush may have destroyed the pres shell and/or
   // WARNING: frames and other layout related objects.
   // WARNING:
@@ -434,13 +439,14 @@ nsSMILAnimationController::DoSample(bool aSkipUnchangedContainers)
   // random order. For animation from/to 'inherit' values to work correctly
   // when the inherited value is *also* being animated, we really should be
   // traversing our animated nodes in an ancestors-first order (bug 501183)
+  bool mightHavePendingStyleUpdates = false;
   for (auto iter = currentCompositorTable->Iter(); !iter.Done(); iter.Next()) {
-    iter.Get()->ComposeAttribute();
+    iter.Get()->ComposeAttribute(mightHavePendingStyleUpdates);
   }
 
   // Update last compositor table
   mLastCompositorTable = currentCompositorTable.forget();
-  mMightHavePendingStyleUpdates = true;
+  mMightHavePendingStyleUpdates = mightHavePendingStyleUpdates;
 
   NS_ASSERTION(!mResampleNeeded, "Resample dirty flag set during sample!");
 }
@@ -596,7 +602,9 @@ nsSMILAnimationController::SampleTimedElement(
 
 /*static*/ void
 nsSMILAnimationController::AddAnimationToCompositorTable(
-  SVGAnimationElement* aElement, nsSMILCompositorTable* aCompositorTable)
+  SVGAnimationElement* aElement,
+  nsSMILCompositorTable* aCompositorTable,
+  bool& aStyleFlushNeeded)
 {
   // Add a compositor to the hash table if there's not already one there
   nsSMILTargetIdentifier key;
@@ -629,6 +637,7 @@ nsSMILAnimationController::AddAnimationToCompositorTable(
     // trigger this same clause in future samples (until it changes again).
     func.ClearHasChanged();
   }
+  aStyleFlushNeeded |= func.ValueNeedsReparsingEverySample();
 }
 
 static inline bool

dom/smil/nsSMILAnimationController.h

@@ -142,8 +142,12 @@ class nsSMILAnimationController final : public nsSMILTimeContainer,
 
   static void SampleTimedElement(mozilla::dom::SVGAnimationElement* aElement,
                                  TimeContainerHashtable* aActiveContainers);
+
   static void AddAnimationToCompositorTable(
-    mozilla::dom::SVGAnimationElement* aElement, nsSMILCompositorTable* aCompositorTable);
+      mozilla::dom::SVGAnimationElement* aElement,
+      nsSMILCompositorTable* aCompositorTable,
+      bool& aStyleFlushNeeded);
+
   static bool GetTargetIdentifierForAnimation(
       mozilla::dom::SVGAnimationElement* aAnimElem, nsSMILTargetIdentifier& aResult);
 

dom/smil/nsSMILAnimationFunction.h

@@ -246,6 +246,14 @@ class nsSMILAnimationFunction
     mWasSkippedInPrevSample = true;
   }
 
+  /**
+   * Returns true if we need to recalculate the animation value on every sample.
+   * (e.g. because it depends on context like the font-size)
+   */
+  bool ValueNeedsReparsingEverySample() const {
+    return mValueNeedsReparsingEverySample;
+  }
+
   // Comparator utility class, used for sorting nsSMILAnimationFunctions
   class Comparator {
     public:

dom/smil/nsSMILCompositor.cpp

@@ -49,7 +49,7 @@ nsSMILCompositor::AddAnimationFunction(nsSMILAnimationFunction* aFunc)
 }
 
 void
-nsSMILCompositor::ComposeAttribute()
+nsSMILCompositor::ComposeAttribute(bool& aMightHavePendingStyleUpdates)
 {
   if (!mKey.mElement)
     return;
@@ -65,6 +65,8 @@ nsSMILCompositor::ComposeAttribute()
     // No active animation functions. (We can still have a nsSMILCompositor in
     // that case if an animation function has *just* become inactive)
     smilAttr->ClearAnimValue();
+    // Removing the animation effect may require a style update.
+    aMightHavePendingStyleUpdates = true;
     return;
   }
 
@@ -88,6 +90,7 @@ nsSMILCompositor::ComposeAttribute()
   }
 
   // FIFTH: Compose animation functions
+  aMightHavePendingStyleUpdates = true;
   uint32_t length = mAnimationFunctions.Length();
   for (uint32_t i = firstFuncToCompose; i < length; ++i) {
     mAnimationFunctions[i]->ComposeResult(*smilAttr, sandwichResultValue);

dom/smil/nsSMILCompositor.h

@@ -52,8 +52,9 @@ class nsSMILCompositor : public PLDHashEntryHdr
 
   // Composes the attribute's current value with the list of animation
   // functions, and assigns the resulting value to this compositor's target
-  // attribute
-  void ComposeAttribute();
+  // attribute. If a change is made that might produce style updates,
+  // aMightHavePendingStyleUpdates is set to true. Otherwise it is not modified.
+  void ComposeAttribute(bool& aMightHavePendingStyleUpdates);
 
   // Clears animation effects on my target attribute
   void ClearAnimationEffects();
@@ -74,7 +75,7 @@ class nsSMILCompositor : public PLDHashEntryHdr
   // Create a nsISMILAttr for my target, on the heap.  Caller is responsible
   // for deallocating the returned object.
   nsISMILAttr* CreateSMILAttr();
-  
+
   // Finds the index of the first function that will affect our animation
   // sandwich. Also toggles the 'mForceCompositing' flag if it finds that any
   // (used) functions have changed.