Skip rule matching during animations.

Source/core/css/resolver/StyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 525 matching lines @@
     adjuster.adjustRenderStyle(state.style(), state.parentStyle(), element, state.cachedUAStyle());
 }
 
 // Start loading resources referenced by this style.
 void StyleResolver::loadPendingResources(StyleResolverState& state)
 {
     m_styleResourceLoader.loadPendingResources(state.style(), state.elementStyleResources());
     document().styleEngine()->fontSelector()->fontLoader()->loadPendingFonts();
 }
 
+struct AnimationResolveData {

[esprehn, 2014/10/13 18:19:33]

I don't think you need this class at all, just add a static function like
animationStartStyle(element) and then null check the result.

[rune, 2014/10/13 21:31:48]

I need to know if I should store a new baseRenderStyle if it was null, too

+
+    AnimationResolveData(Element* element)
+        : baseRenderStyle(nullptr)
+        , useBaseRenderStyle(false)

[esprehn, 2014/10/13 18:19:33]

The useBaseRenderStyle bit doesn't seem needed, just null check the base render
style.

[rune, 2014/10/13 21:31:48]

I don't want to store two RenderStyles unless I'm animating with
isAnimationStyleChange(). So, I need to know the value of
isAnimationStyleChange(), and the baseRenderStyle if it was previously stored.
The reason I use a struct is to share the code between styleForElement and
pseudoStyleForElementInternal(). It's also a way to hide the ASSERT. I could've
used two methods with two variables instead.

+    {
+        if (!element)
+            return;
+
+        if (ActiveAnimations* animations = element->activeAnimations()) {
+            useBaseRenderStyle = animations->isAnimationStyleChange();
+            if (useBaseRenderStyle)
+                baseRenderStyle = animations->baseRenderStyle();
+            else
+                animations->setBaseRenderStyle(nullptr);
+
+#if ENABLE(ASSERT)
+            // Force recalc of the base style to check that the cached one was correct.
+            baseRenderStyle = nullptr;
+#endif // !ASSERT
+        }
+    }
+
+    const RenderStyle* baseRenderStyle;
+    bool useBaseRenderStyle;
+};
+
 PassRefPtr<RenderStyle> StyleResolver::styleForElement(Element* element, RenderStyle* defaultParent, StyleSharingBehavior sharingBehavior,
     RuleMatchingBehavior matchingBehavior)
 {
     ASSERT(document().frame());
     ASSERT(document().settings());
     ASSERT(!hasPendingAuthorStyleSheets());
     ASSERT(!m_needCollectFeatures);
 
     // Once an element has a renderer, we don't try to destroy it, since otherwise the renderer
     // will vanish if a style recalc happens during loading.
@@ skipping 15 matching lines @@
     if (element == document().documentElement())
         resetDirectionAndWritingModeOnDocument(document());
     StyleResolverState state(document(), element, defaultParent);
 
     if (sharingBehavior == AllowStyleSharing && state.parentStyle()) {
         SharedStyleFinder styleFinder(state.elementContext(), m_features, m_siblingRuleSet.get(), m_uncommonAttributeRuleSet.get(), *this);
         if (RefPtr<RenderStyle> sharedStyle = styleFinder.findSharedStyle())
             return sharedStyle.release();
     }
 
-    if (state.parentStyle()) {
+
+    AnimationResolveData animationData(element);
+
+    if (animationData.baseRenderStyle) {
+        state.setStyle(RenderStyle::clone(animationData.baseRenderStyle));
+    } else if (state.parentStyle()) {
         state.setStyle(RenderStyle::create());
         state.style()->inheritFrom(state.parentStyle(), isAtShadowBoundary(element) ? RenderStyle::AtShadowBoundary : RenderStyle::NotAtShadowBoundary);
     } else {
         state.setStyle(defaultStyleForElement());
         state.setParentStyle(RenderStyle::clone(state.style()));
     }
     // contenteditable attribute (implemented by -webkit-user-modify) should
     // be propagated from shadow host to distributed node.
     if (state.distributedToInsertionPoint()) {
         if (Element* parent = element->parentElement()) {
             if (RenderStyle* styleOfShadowHost = parent->renderStyle())
                 state.style()->setUserModify(styleOfShadowHost->userModify());
         }
     }
 
     state.fontBuilder().initForStyleResolve(state.document(), state.style());
 
     if (element->isLink()) {
         state.style()->setIsLink(true);
         EInsideLink linkState = state.elementLinkState();
         if (linkState != NotInsideLink) {
             bool forceVisited = InspectorInstrumentation::forcePseudoState(element, CSSSelector::PseudoVisited);
             if (forceVisited)
                 linkState = InsideVisitedLink;
         }
         state.style()->setInsideLink(linkState);
     }
 
-    bool needsCollection = false;
-    CSSDefaultStyleSheets::instance().ensureDefaultStyleSheetsForElement(element, needsCollection);
-    if (needsCollection)
-        collectFeatures();
+    if (!animationData.baseRenderStyle) {
 
-    {
+        bool needsCollection = false;
+        CSSDefaultStyleSheets::instance().ensureDefaultStyleSheetsForElement(element, needsCollection);
+        if (needsCollection)
+            collectFeatures();
+
         ElementRuleCollector collector(state.elementContext(), m_selectorFilter, state.style());
 
         matchAllRules(state, collector, matchingBehavior != MatchAllRulesExcludingSMIL);
 
         applyMatchedProperties(state, collector.matchedResult());
         applyCallbackSelectors(state);
 
         addContentAttrValuesToFeatures(state.contentAttrValues(), m_features);
+
+        // Cache our original display.
+        state.style()->setOriginalDisplay(state.style()->display());
+
+        adjustRenderStyle(state, element);
+
+        if (animationData.useBaseRenderStyle)
+            element->activeAnimations()->setBaseRenderStyle(RenderStyle::clone(state.style()));
     }
 
-    // Cache our original display.
-    state.style()->setOriginalDisplay(state.style()->display());
-
-    adjustRenderStyle(state, element);
-
     // FIXME: The CSSWG wants to specify that the effects of animations are applied before
     // important rules, but this currently happens here as we require adjustment to have happened
     // before deciding which properties to transition.
     if (applyAnimatedProperties(state, element))
         adjustRenderStyle(state, element);
 
     if (isHTMLBodyElement(*element))
         document().textLinkColors().setTextColor(state.style()->color());
 
     setAnimationUpdateIfNeeded(state, *element);
@@ skipping 113 matching lines @@
 }
 
 bool StyleResolver::pseudoStyleForElementInternal(Element& element, const PseudoStyleRequest& pseudoStyleRequest, RenderStyle* parentStyle, StyleResolverState& state)
 {
     ASSERT(document().frame());
     ASSERT(document().settings());
     ASSERT(pseudoStyleRequest.pseudoId != FIRST_LINE_INHERITED);
 
     StyleResolverParentScope::ensureParentStackIsPushed();
 
-    if (pseudoStyleRequest.allowsInheritance(state.parentStyle())) {
+    Element* pseudoElement = element.pseudoElement(pseudoStyleRequest.pseudoId);
+
+    AnimationResolveData animationData(pseudoElement);
+
+    if (animationData.baseRenderStyle) {
+        state.setStyle(RenderStyle::clone(animationData.baseRenderStyle));
+    } else if (pseudoStyleRequest.allowsInheritance(state.parentStyle())) {
         state.setStyle(RenderStyle::create());
         state.style()->inheritFrom(state.parentStyle());
     } else {
         state.setStyle(defaultStyleForElement());
         state.setParentStyle(RenderStyle::clone(state.style()));
     }
 
     state.style()->setStyleType(pseudoStyleRequest.pseudoId);
     state.fontBuilder().initForStyleResolve(state.document(), state.style());
 
     // Since we don't use pseudo-elements in any of our quirk/print
     // user agent rules, don't waste time walking those rules.
 
-    {
+    if (!animationData.baseRenderStyle) {
         // Check UA, user and author rules.
         ElementRuleCollector collector(state.elementContext(), m_selectorFilter, state.style());
         collector.setPseudoStyleRequest(pseudoStyleRequest);
 
         matchUARules(collector);
         matchAuthorRules(state.element(), collector, false);
 
         if (collector.matchedResult().matchedProperties.isEmpty())
             return false;
 
         applyMatchedProperties(state, collector.matchedResult());
         applyCallbackSelectors(state);
 
         addContentAttrValuesToFeatures(state.contentAttrValues(), m_features);
+
+        // Cache our original display.
+        state.style()->setOriginalDisplay(state.style()->display());
+
+        // FIXME: Passing 0 as the Element* introduces a lot of complexity
+        // in the adjustRenderStyle code.
+        adjustRenderStyle(state, 0);
+
+        if (animationData.useBaseRenderStyle)
+            pseudoElement->activeAnimations()->setBaseRenderStyle(RenderStyle::clone(state.style()));
     }
 
-    // Cache our original display.
-    state.style()->setOriginalDisplay(state.style()->display());
-
-    // FIXME: Passing 0 as the Element* introduces a lot of complexity
-    // in the adjustRenderStyle code.
-    adjustRenderStyle(state, 0);
-
     // FIXME: The CSSWG wants to specify that the effects of animations are applied before
     // important rules, but this currently happens here as we require adjustment to have happened
     // before deciding which properties to transition.
-    if (applyAnimatedProperties(state, element.pseudoElement(pseudoStyleRequest.pseudoId)))
+    if (applyAnimatedProperties(state, pseudoElement))
         adjustRenderStyle(state, 0);
 
     didAccess();
 
     if (state.style()->hasViewportUnits())
         document().setHasViewportUnits();
 
     return true;
 }
 
@@ skipping 766 matching lines @@
     visitor->trace(m_uncommonAttributeRuleSet);
     visitor->trace(m_watchedSelectorsRules);
     visitor->trace(m_treeBoundaryCrossingRules);
     visitor->trace(m_styleSharingLists);
     visitor->trace(m_pendingStyleSheets);
     visitor->trace(m_document);
 #endif
 }
 
 } // namespace blink