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

Source/core/css/RuleFeature.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 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 14 matching lines @@
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "config.h"
 #include "core/css/RuleFeature.h"
 
 #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"
 #include "core/dom/Node.h"
 #include "core/inspector/InspectorTraceEvents.h"
 #include "wtf/BitVector.h"
 
 namespace blink {
 
 #if ENABLE(ASSERT)
@@ skipping 233 matching lines @@
 void RuleFeatureSet::updateInvalidationSets(const CSSSelector& selector)
 {
     InvalidationSetFeatures features;
     auto result = extractInvalidationSetFeatures(selector, features, false);
     if (result.first) {
         features.forceSubtree = result.second == ForceSubtree;
         addFeaturesToInvalidationSets(*result.first, features);
     }
 }
 
+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)
 {
     bool foundFeatures = false;
     for (const CSSSelector* current = &selector; current; current = current->tagHistory()) {
         if (!negated)
             foundFeatures |= extractInvalidationSetFeature(*current, features);
         // Initialize the entry in the invalidation set map, if supported.
         if (!invalidationSetForSelector(*current)) {
             if (requiresSubtreeInvalidation(*current)) {
@@ skipping 86 matching lines @@
         if (current->relation() == CSSSelector::SubSelector)
             continue;
 
         if (current->isShadowSelector())
             features.treeBoundaryCrossing = true;
 
         features.adjacent = current->isAdjacentSelector();
     }
 }
 
-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);
     m_metadata.add(metadata);
 
     if (metadata.foundSiblingSelector)
         siblingRules.append(RuleFeature(ruleData.rule(), ruleData.selectorIndex(), ruleData.hasDocumentSecurityOrigin()));
     if (ruleData.containsUncommonAttributeSelector())
         uncommonAttributeRules.append(RuleFeature(ruleData.rule(), ruleData.selectorIndex(), ruleData.hasDocumentSecurityOrigin()));
 }
@@ skipping 197 matching lines @@
     visitor->trace(uncommonAttributeRules);
     visitor->trace(m_classInvalidationSets);
     visitor->trace(m_attributeInvalidationSets);
     visitor->trace(m_idInvalidationSets);
     visitor->trace(m_pseudoInvalidationSets);
     visitor->trace(m_styleInvalidator);
 #endif
 }
 
 } // namespace blink