Cascade declared property values instead of applying values on top of each other

Source/core/css/resolver/StyleResolver.cpp

Index: Source/core/css/resolver/StyleResolver.cpp
diff --git a/Source/core/css/resolver/StyleResolver.cpp b/Source/core/css/resolver/StyleResolver.cpp
index def181eac3c036c4beab0c9f3e919080452af308..7d204bfe79270ec7c1393e80e3457d81ea7f8adc 100644
--- a/Source/core/css/resolver/StyleResolver.cpp
+++ b/Source/core/css/resolver/StyleResolver.cpp
@@ -31,7 +31,6 @@
 
 #include "core/CSSPropertyNames.h"
 #include "core/HTMLNames.h"
-#include "core/StylePropertyShorthand.h"
 #include "core/animation/ActiveAnimations.h"
 #include "core/animation/Animation.h"
 #include "core/animation/AnimationTimeline.h"
@@ -59,6 +58,7 @@
 #include "core/css/StyleSheetContents.h"
 #include "core/css/parser/BisonCSSParser.h"
 #include "core/css/resolver/AnimatedStyleBuilder.h"
+#include "core/css/resolver/CascadedValues.h"
 #include "core/css/resolver/MatchResult.h"
 #include "core/css/resolver/MediaQueryResult.h"
 #include "core/css/resolver/SharedStyleFinder.h"
@@ -97,6 +97,18 @@ void setAnimationUpdateIfNeeded(StyleResolverState& state, Element& element)
         element.ensureActiveAnimations().cssAnimations().setPendingUpdate(state.takeAnimationUpdate());
 }
 
+static bool elementTypeHasAppearanceFromUAStyle(const Element& element)
+{
+    // These elements have -webkit-appearance specified in html.css
+    const AtomicString& localName = element.localName();
+    return localName == HTMLNames::inputTag
+        || localName == HTMLNames::textareaTag
+        || localName == HTMLNames::buttonTag
+        || localName == HTMLNames::progressTag
+        || localName == HTMLNames::selectTag
+        || localName == HTMLNames::meterTag;
+}
+
 } // namespace
 
 namespace blink {
@@ -679,6 +691,38 @@ PassRefPtr<RenderStyle> StyleResolver::styleForElement(Element* element, RenderS
     return state.takeStyle();
 }
 
+// FIXME: Consider refactoring to create a new class which owns the following
+// first/last/range properties.
+// c.f. //src/third_party/WebKit/Source/core/css/CSSPropertyNames.in.
+
+template<> CSSPropertyID StyleResolver::firstCSSPropertyId<StyleResolver::HighPriorityProperties>()
+{
+    COMPILE_ASSERT(CSSPropertyColor == CSSPropertyWebkitWritingMode + 1, CSS_color_is_first_high_priority_property);
+    return CSSPropertyColor;
+}
+
+template<> CSSPropertyID StyleResolver::lastCSSPropertyId<StyleResolver::HighPriorityProperties>()
+{
+    return CSSPropertyZoom;
+}
+
+template<> CSSPropertyID StyleResolver::firstCSSPropertyId<StyleResolver::LowPriorityProperties>()
+{
+    COMPILE_ASSERT(CSSPropertyBackground == CSSPropertyZoom + 1, CSS_background_is_first_low_priority_property);
+    return CSSPropertyBackground;
+}
+
+template<> CSSPropertyID StyleResolver::lastCSSPropertyId<StyleResolver::LowPriorityProperties>()
+{
+    return convertToCSSPropertyID(lastCSSProperty);
+}
+
+template <StyleResolver::StyleApplicationPass pass>
+bool StyleResolver::isPropertyForPass(CSSPropertyID property)
+{
+    return firstCSSPropertyId<pass>() <= property && property <= lastCSSPropertyId<pass>();
+}
+
 PassRefPtr<RenderStyle> StyleResolver::styleForKeyframe(Element* element, const RenderStyle& elementStyle, RenderStyle* parentStyle, const StyleKeyframe* keyframe, const AtomicString& animationName)
 {
     ASSERT(document().frame());
@@ -689,34 +733,24 @@ PassRefPtr<RenderStyle> StyleResolver::styleForKeyframe(Element* element, const
         resetDirectionAndWritingModeOnDocument(document());
     StyleResolverState state(document(), element, parentStyle);
 
-    MatchResult result;
-    result.addMatchedProperties(&keyframe->properties());
+    MatchResult matchResult;
+    matchResult.addMatchedProperties(&keyframe->properties());
 
     ASSERT(!state.style());
 
     // Create the style
     state.setStyle(RenderStyle::clone(&elementStyle));
-    state.setLineHeightValue(0);
 
     state.fontBuilder().initForStyleResolve(state.document(), state.style());
 
-    // We don't need to bother with !important. Since there is only ever one
-    // decl, there's nothing to override. So just add the first properties.
-    // We also don't need to bother with animation properties since the only
-    // relevant one is animation-timing-function and we special-case that in
-    // CSSAnimations.cpp
-    bool inheritedOnly = false;
-    applyMatchedProperties<HighPriorityProperties>(state, result, false, 0, result.matchedProperties.size() - 1, inheritedOnly);
+    CascadedValues cascadedValues(state, matchResult);
+
+    cascadedValues.applyValues(firstCSSPropertyId<HighPriorityProperties>(), lastCSSPropertyId<HighPriorityProperties>());
 
     // If our font got dirtied, go ahead and update it now.
     updateFont(state);
 
-    // Line-height is set when we are sure we decided on the font-size
-    if (state.lineHeightValue())
-        StyleBuilder::applyProperty(CSSPropertyLineHeight, state, state.lineHeightValue());
-
-    // Now do rest of the properties.
-    applyMatchedProperties<LowPriorityProperties>(state, result, false, 0, result.matchedProperties.size() - 1, inheritedOnly);
+    cascadedValues.applyValues(firstCSSPropertyId<LowPriorityProperties>(), lastCSSPropertyId<LowPriorityProperties>());
 
     loadPendingResources(state);
 
@@ -883,20 +917,15 @@ PassRefPtr<RenderStyle> StyleResolver::styleForPage(int pageIndex)
     if (ScopedStyleResolver* scopedResolver = document().scopedStyleResolver())
         scopedResolver->matchPageRules(collector);
 
-    state.setLineHeightValue(0);
-    bool inheritedOnly = false;
+    MatchResult& matchResult = collector.matchedResult();
+    CascadedValues cascadedValues(state, matchResult);
 
-    MatchResult& result = collector.matchedResult();
-    applyMatchedProperties<HighPriorityProperties>(state, result, false, 0, result.matchedProperties.size() - 1, inheritedOnly);
+    cascadedValues.applyValues(firstCSSPropertyId<HighPriorityProperties>(), lastCSSPropertyId<HighPriorityProperties>());
 
     // If our font got dirtied, go ahead and update it now.
     updateFont(state);
 
-    // Line-height is set when we are sure we decided on the font-size.
-    if (state.lineHeightValue())
-        StyleBuilder::applyProperty(CSSPropertyLineHeight, state, state.lineHeightValue());
-
-    applyMatchedProperties<LowPriorityProperties>(state, result, false, 0, result.matchedProperties.size() - 1, inheritedOnly);
+    cascadedValues.applyValues(firstCSSPropertyId<LowPriorityProperties>(), lastCSSPropertyId<LowPriorityProperties>());
 
     addContentAttrValuesToFeatures(state.contentAttrValues(), m_features);
 
@@ -931,7 +960,6 @@ PassRefPtr<RenderStyle> StyleResolver::defaultStyleForElement()
     state.setStyle(RenderStyle::create());
     state.fontBuilder().initForStyleResolve(document(), state.style());
     state.style()->setLineHeight(RenderStyle::initialLineHeight());
-    state.setLineHeightValue(0);
     state.fontBuilder().setInitial(state.style()->effectiveZoom());
     state.style()->font().update(document().styleEngine()->fontSelector());
     return state.takeStyle();
@@ -1015,6 +1043,9 @@ bool StyleResolver::applyAnimatedProperties(StyleResolverState& state, Element*
 
     const WillBeHeapHashMap<CSSPropertyID, RefPtrWillBeMember<Interpolation> >& activeInterpolationsForAnimations = state.animationUpdate()->activeInterpolationsForAnimations();
     const WillBeHeapHashMap<CSSPropertyID, RefPtrWillBeMember<Interpolation> >& activeInterpolationsForTransitions = state.animationUpdate()->activeInterpolationsForTransitions();
+
+    // FIXME: Is it possible to use CascadedValues here or is it too expensive to
+    // convert from Interpolations to CSSValues?
     applyAnimatedProperties<HighPriorityProperties>(state, activeInterpolationsForAnimations);
     applyAnimatedProperties<HighPriorityProperties>(state, activeInterpolationsForTransitions);
 
@@ -1089,7 +1120,7 @@ void StyleResolver::applyAnimatedProperties(StyleResolverState& state, const Wil
     }
 }
 
-static inline bool isValidCueStyleProperty(CSSPropertyID id)
+bool StyleResolver::isValidCueStyleProperty(CSSPropertyID id)
 {
     switch (id) {
     case CSSPropertyBackground:
@@ -1138,7 +1169,7 @@ static inline bool isValidCueStyleProperty(CSSPropertyID id)
     return false;
 }
 
-static inline bool isValidFirstLetterStyleProperty(CSSPropertyID id)
+bool StyleResolver::isValidFirstLetterStyleProperty(CSSPropertyID id)
 {
     switch (id) {
     // Valid ::first-letter properties listed in spec:
@@ -1259,154 +1290,6 @@ static inline bool isValidFirstLetterStyleProperty(CSSPropertyID id)
     }
 }
 
-// FIXME: Consider refactoring to create a new class which owns the following
-// first/last/range properties.
-// This method returns the first CSSPropertyId of high priority properties.
-// Other properties can depend on high priority properties. For example,
-// border-color property with currentColor value depends on color property.
-// All high priority properties are obtained by using
-// firstCSSPropertyId<HighPriorityProperties> and
-// lastCSSPropertyId<HighPriorityProperties>.
-template<> CSSPropertyID StyleResolver::firstCSSPropertyId<StyleResolver::HighPriorityProperties>()
-{
-    COMPILE_ASSERT(CSSPropertyColor == firstCSSProperty, CSS_color_is_first_high_priority_property);
-    return CSSPropertyColor;
-}
-
-// This method returns the last CSSPropertyId of high priority properties.
-template<> CSSPropertyID StyleResolver::lastCSSPropertyId<StyleResolver::HighPriorityProperties>()
-{
-    COMPILE_ASSERT(CSSPropertyLineHeight == CSSPropertyColor + 18, CSS_line_height_is_end_of_high_prioity_property_range);
-    COMPILE_ASSERT(CSSPropertyZoom == CSSPropertyLineHeight - 1, CSS_zoom_is_before_line_height);
-    return CSSPropertyLineHeight;
-}
-
-// This method returns the first CSSPropertyId of remaining properties,
-// i.e. low priority properties. No properties depend on low priority
-// properties. So we don't need to resolve such properties quickly.
-// All low priority properties are obtained by using
-// firstCSSPropertyId<LowPriorityProperties> and
-// lastCSSPropertyId<LowPriorityProperties>.
-template<> CSSPropertyID StyleResolver::firstCSSPropertyId<StyleResolver::LowPriorityProperties>()
-{
-    COMPILE_ASSERT(CSSPropertyBackground == CSSPropertyLineHeight + 1, CSS_background_is_first_low_priority_property);
-    return CSSPropertyBackground;
-}
-
-// This method returns the last CSSPropertyId of low priority properties.
-template<> CSSPropertyID StyleResolver::lastCSSPropertyId<StyleResolver::LowPriorityProperties>()
-{
-    return static_cast<CSSPropertyID>(lastCSSProperty);
-}
-
-template <StyleResolver::StyleApplicationPass pass>
-bool StyleResolver::isPropertyForPass(CSSPropertyID property)
-{
-    return firstCSSPropertyId<pass>() <= property && property <= lastCSSPropertyId<pass>();
-}
-
-// This method expands the 'all' shorthand property to longhand properties
-// and applies the expanded longhand properties.
-template <StyleResolver::StyleApplicationPass pass>
-void StyleResolver::applyAllProperty(StyleResolverState& state, CSSValue* allValue)
-{
-    bool isUnsetValue = !allValue->isInitialValue() && !allValue->isInheritedValue();
-    unsigned startCSSProperty = firstCSSPropertyId<pass>();
-    unsigned endCSSProperty = lastCSSPropertyId<pass>();
-
-    for (unsigned i = startCSSProperty; i <= endCSSProperty; ++i) {
-        CSSPropertyID propertyId = static_cast<CSSPropertyID>(i);
-
-        // StyleBuilder does not allow any expanded shorthands.
-        if (isExpandedShorthandForAll(propertyId))
-            continue;
-
-        // all shorthand spec says:
-        // The all property is a shorthand that resets all CSS properties
-        // except direction and unicode-bidi.
-        // c.f. http://dev.w3.org/csswg/css-cascade/#all-shorthand
-        // We skip applyProperty when a given property is unicode-bidi or
-        // direction.
-        if (!CSSProperty::isAffectedByAllProperty(propertyId))
-            continue;
-
-        CSSValue* value;
-        if (!isUnsetValue) {
-            value = allValue;
-        } else {
-            if (CSSProperty::isInheritedProperty(propertyId))
-                value = cssValuePool().createInheritedValue().get();
-            else
-                value = cssValuePool().createExplicitInitialValue().get();
-        }
-        StyleBuilder::applyProperty(propertyId, state, value);
-    }
-}
-
-template <StyleResolver::StyleApplicationPass pass>
-void StyleResolver::applyProperties(StyleResolverState& state, const StylePropertySet* properties, StyleRule* rule, bool isImportant, bool inheritedOnly, PropertyWhitelistType propertyWhitelistType)
-{
-    state.setCurrentRule(rule);
-
-    unsigned propertyCount = properties->propertyCount();
-    for (unsigned i = 0; i < propertyCount; ++i) {
-        StylePropertySet::PropertyReference current = properties->propertyAt(i);
-        if (isImportant != current.isImportant())
-            continue;
-
-        CSSPropertyID property = current.id();
-        if (property == CSSPropertyAll) {
-            applyAllProperty<pass>(state, current.value());
-            continue;
-        }
-
-        if (inheritedOnly && !current.isInherited()) {
-            // If the property value is explicitly inherited, we need to apply further non-inherited properties
-            // as they might override the value inherited here. For this reason we don't allow declarations with
-            // explicitly inherited properties to be cached.
-            ASSERT(!current.value()->isInheritedValue());
-            continue;
-        }
-
-        if (propertyWhitelistType == PropertyWhitelistCue && !isValidCueStyleProperty(property))
-            continue;
-        if (propertyWhitelistType == PropertyWhitelistFirstLetter && !isValidFirstLetterStyleProperty(property))
-            continue;
-        if (!isPropertyForPass<pass>(property))
-            continue;
-        if (pass == HighPriorityProperties && property == CSSPropertyLineHeight)
-            state.setLineHeightValue(current.value());
-        else
-            StyleBuilder::applyProperty(current.id(), state, current.value());
-    }
-}
-
-template <StyleResolver::StyleApplicationPass pass>
-void StyleResolver::applyMatchedProperties(StyleResolverState& state, const MatchResult& matchResult, bool isImportant, int startIndex, int endIndex, bool inheritedOnly)
-{
-    if (startIndex == -1)
-        return;
-
-    if (state.style()->insideLink() != NotInsideLink) {
-        for (int i = startIndex; i <= endIndex; ++i) {
-            const MatchedProperties& matchedProperties = matchResult.matchedProperties[i];
-            unsigned linkMatchType = matchedProperties.m_types.linkMatchType;
-            // FIXME: It would be nicer to pass these as arguments but that requires changes in many places.
-            state.setApplyPropertyToRegularStyle(linkMatchType & SelectorChecker::MatchLink);
-            state.setApplyPropertyToVisitedLinkStyle(linkMatchType & SelectorChecker::MatchVisited);
-
-            applyProperties<pass>(state, matchedProperties.properties.get(), matchResult.matchedRules[i], isImportant, inheritedOnly, static_cast<PropertyWhitelistType>(matchedProperties.m_types.whitelistType));
-        }
-        state.setApplyPropertyToRegularStyle(true);
-        state.setApplyPropertyToVisitedLinkStyle(false);
-        return;
-    }
-    for (int i = startIndex; i <= endIndex; ++i) {
-        const MatchedProperties& matchedProperties = matchResult.matchedProperties[i];
-        applyProperties<pass>(state, matchedProperties.properties.get(), matchResult.matchedRules[i], isImportant, inheritedOnly, static_cast<PropertyWhitelistType>(matchedProperties.m_types.whitelistType));
-    }
-}
-
 static unsigned computeMatchedPropertiesHash(const MatchedProperties* properties, unsigned size)
 {
     return StringHasher::hashMemory(properties, sizeof(MatchedProperties) * size);
@@ -1456,15 +1339,8 @@ void StyleResolver::applyMatchedProperties(StyleResolverState& state, const Matc
         applyInheritedOnly = true;
     }
 
-    // Now we have all of the matched rules in the appropriate order. Walk the rules and apply
-    // high-priority properties first, i.e., those properties that other properties depend on.
-    // The order is (1) high-priority not important, (2) high-priority important, (3) normal not important
-    // and (4) normal important.
-    state.setLineHeightValue(0);
-    applyMatchedProperties<HighPriorityProperties>(state, matchResult, false, 0, matchResult.matchedProperties.size() - 1, applyInheritedOnly);
-    applyMatchedProperties<HighPriorityProperties>(state, matchResult, true, matchResult.ranges.firstAuthorRule, matchResult.ranges.lastAuthorRule, applyInheritedOnly);
-    applyMatchedProperties<HighPriorityProperties>(state, matchResult, true, matchResult.ranges.firstUserRule, matchResult.ranges.lastUserRule, applyInheritedOnly);
-    applyMatchedProperties<HighPriorityProperties>(state, matchResult, true, matchResult.ranges.firstUARule, matchResult.ranges.lastUARule, applyInheritedOnly);
+    CascadedValues cascadedValues(state, matchResult);
+    cascadedValues.applyValues(firstCSSPropertyId<HighPriorityProperties>(), lastCSSPropertyId<HighPriorityProperties>(), applyInheritedOnly);
 
     if (UNLIKELY(isSVGForeignObjectElement(element))) {
         // RenderSVGRoot handles zooming for the whole SVG subtree, so foreignObject content should not be scaled again.
@@ -1485,25 +1361,22 @@ void StyleResolver::applyMatchedProperties(StyleResolverState& state, const Matc
     // If our font got dirtied, go ahead and update it now.
     updateFont(state);
 
-    // Line-height is set when we are sure we decided on the font-size.
-    if (state.lineHeightValue())
-        StyleBuilder::applyProperty(CSSPropertyLineHeight, state, state.lineHeightValue());
-
     // Many properties depend on the font. If it changes we just apply all properties.
     if (cachedMatchedProperties && cachedMatchedProperties->renderStyle->fontDescription() != state.style()->fontDescription())
         applyInheritedOnly = false;
 
-    // Now do the normal priority UA properties.
-    applyMatchedProperties<LowPriorityProperties>(state, matchResult, false, matchResult.ranges.firstUARule, matchResult.ranges.lastUARule, applyInheritedOnly);
-
-    // Cache the UA properties to pass them to RenderTheme in adjustRenderStyle.
-    state.cacheUserAgentBorderAndBackground();
+    // This code supports -webkit-appearance, for which we are interested
+    // in whether the user has specified border or background properties.
+    // FIXME: This is a bit of a mess, we should just compare CSSValues and
+    // store a single bit for this.
+    if (elementTypeHasAppearanceFromUAStyle(*element)) {
+        CascadedValues userAgentValues(state, matchResult, true);
+        // We only actually care about border and background properties here
+        userAgentValues.applyValues(firstCSSPropertyId<LowPriorityProperties>(), lastCSSPropertyId<LowPriorityProperties>(), applyInheritedOnly);
+        state.cacheUserAgentBorderAndBackground();
+    }
 
-    // Now do the author and user normal priority properties and all the !important properties.
-    applyMatchedProperties<LowPriorityProperties>(state, matchResult, false, matchResult.ranges.lastUARule + 1, matchResult.matchedProperties.size() - 1, applyInheritedOnly);
-    applyMatchedProperties<LowPriorityProperties>(state, matchResult, true, matchResult.ranges.firstAuthorRule, matchResult.ranges.lastAuthorRule, applyInheritedOnly);
-    applyMatchedProperties<LowPriorityProperties>(state, matchResult, true, matchResult.ranges.firstUserRule, matchResult.ranges.lastUserRule, applyInheritedOnly);
-    applyMatchedProperties<LowPriorityProperties>(state, matchResult, true, matchResult.ranges.firstUARule, matchResult.ranges.lastUARule, applyInheritedOnly);
+    cascadedValues.applyValues(firstCSSPropertyId<LowPriorityProperties>(), lastCSSPropertyId<LowPriorityProperties>(), applyInheritedOnly);
 
     loadPendingResources(state);