Collect content:attr(...)-features in RuleFeatureSet.

Source/core/css/RuleFeature.cpp

Index: Source/core/css/RuleFeature.cpp
diff --git a/Source/core/css/RuleFeature.cpp b/Source/core/css/RuleFeature.cpp
index 6867a79efa45b493905d8b8eb4201b38b3456d54..c7da88e148d484e4371fc2ae4b9973c40229ff84 100644
--- a/Source/core/css/RuleFeature.cpp
+++ b/Source/core/css/RuleFeature.cpp
@@ -32,7 +32,9 @@
 #include "core/HTMLNames.h"
 #include "core/css/CSSSelector.h"
 #include "core/css/CSSSelectorList.h"
+#include "core/css/CSSValueList.h"
 #include "core/css/RuleSet.h"
+#include "core/css/StylePropertySet.h"
 #include "core/css/StyleRule.h"
 #include "core/css/invalidation/DescendantInvalidationSet.h"
 #include "core/dom/Element.h"
@@ -286,6 +288,32 @@ void RuleFeatureSet::updateInvalidationSets(const CSSSelector& selector)
     }
 }
 
+void RuleFeatureSet::updateInvalidationSetsForContentAttribute(StyleRule* styleRule)
+{
+    const StylePropertySet& propertySet = styleRule->properties();
+
+    int propertyIndex = propertySet.findPropertyIndex(CSSPropertyContent);
+
+    if (propertyIndex == -1)
+        return;
+
+    StylePropertySet::PropertyReference contentProperty = propertySet.propertyAt(propertyIndex);
+    CSSValue* contentValue = contentProperty.value();
+
+    if (!contentValue->isValueList())
+        return;
+
+    for (CSSValueListIterator i = contentValue; i.hasMore(); i.advance()) {
+        CSSValue* item = i.value();
+        if (!item->isPrimitiveValue())
+            continue;
+        CSSPrimitiveValue* primitiveItem = toCSSPrimitiveValue(item);
+        if (!primitiveItem->isAttr())
+            continue;
+        ensureAttributeInvalidationSet(AtomicString(primitiveItem->getStringValue()));
+    }
+}
+
 std::pair<const CSSSelector*, RuleFeatureSet::UseFeaturesType>
 RuleFeatureSet::extractInvalidationSetFeatures(const CSSSelector& selector, InvalidationSetFeatures& features, bool negated)
 {
@@ -392,14 +420,10 @@ void RuleFeatureSet::addFeaturesToInvalidationSets(const CSSSelector& selector,
     }
 }
 
-void RuleFeatureSet::addContentAttr(const AtomicString& attributeName)
-{
-    ensureAttributeInvalidationSet(attributeName);
-}
-
 void RuleFeatureSet::collectFeaturesFromRuleData(const RuleData& ruleData)
 {
     updateInvalidationSets(ruleData.selector());
+    updateInvalidationSetsForContentAttribute(ruleData.rule());

[rune, 2014/12/10 13:03:55]

There's one RuleData per selector in the selector list, so:

#a::before, #b::before {
  content: attr(number);
}

Will add "number" twice.

I like that the fact that this code is clean, but also since we're already
walking through all selector components in updateInvalidationSets, and content
currently only applies to ::before and ::after, I was wondering if we could
avoid the findPropertyIndex in most rules.

 
     FeatureMetadata metadata;
     collectFeaturesFromSelector(ruleData.selector(), metadata);