Add a first pass of a class descendant invalidator, and a containing RuleSetAnalyzer

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index 45ff5c326d6a6bf146c7c1bd35870a4174f8f4e0..9db7684cfac0b7c5e940df7325c8cb4ee07d8161 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -1045,21 +1045,24 @@ static inline bool classStringHasClassName(const AtomicString& newClassString)
 }
 
 template<typename Checker>
-static bool checkSelectorForClassChange(const SpaceSplitString& changedClasses, const Checker& checker)
+static bool checkSelectorForClassChange(const SpaceSplitString& changedClasses, const Checker& checker, Element* element)
 {
     unsigned changedSize = changedClasses.size();
     for (unsigned i = 0; i < changedSize; ++i) {
-        if (checker.hasSelectorForClass(changedClasses[i]))
+        const RuleSetAnalyzer* ruleSetAnalyzer = checker.getRuleSetAnalyzer();
+        if (ruleSetAnalyzer)
+            ruleSetAnalyzer->invalidateElementSubtreeForClassChange(changedClasses[i], element);

[esprehn, 2014/01/14 21:32:56]

I had envisioned doing this in a single pass, not walking the subtree
repeatedly. This is doing to doing awful things to Modernizer apps:

ex.

body.className = "foo bar baz biz bam" will walk the entire document 5 times.

We can land this as-is, but we should do it behind a flag then and iterate on
combining the passes.

[esprehn, 2014/01/14 21:32:56]

You ignore the return value of invalidateElementSubtreeForClassChange which is
not right, you want to combine the getRuleSetAnalyzer() and the
invalidateElementSubtreeForClassChange steps into a method on checker.

if (checker.invalidateForClass(changedClasses[i], element))
  continue;
if (checker.hasSelectorForClass(changedClasses[i]))
  return true;

[chrishtr, 2014/01/14 23:33:00]

Done.

[chrishtr, 2014/01/14 23:33:00]

Done.

+        else if (checker.hasSelectorForClass(changedClasses[i]))
             return true;
     }
     return false;
 }
 
 template<typename Checker>
-static bool checkSelectorForClassChange(const SpaceSplitString& oldClasses, const SpaceSplitString& newClasses, const Checker& checker)
+static bool checkSelectorForClassChange(const SpaceSplitString& oldClasses, const SpaceSplitString& newClasses, const Checker& checker, Element* element)
 {
     if (!oldClasses.size())
-        return checkSelectorForClassChange(newClasses, checker);
+        return checkSelectorForClassChange(newClasses, checker, element);
 
     // Class vectors tend to be very short. This is faster than using a hash table.
     BitVector remainingClassBits;
@@ -1077,15 +1080,25 @@ static bool checkSelectorForClassChange(const SpaceSplitString& oldClasses, cons
             }
         }
         // Class was added.
-        if (!found && checker.hasSelectorForClass(newClasses[i]))
-            return true;
+
+        if (!found) {
+            const RuleSetAnalyzer* ruleSetAnalyzer = checker.getRuleSetAnalyzer();
+            if (ruleSetAnalyzer)

[esprehn, 2014/01/14 21:32:56]

Combing if and get, if (const RuleSet.... = checker.rulesetAnalyzer(...)).

invalidateElementSubtreeForClassChange also returns a bool, but you ignore it
here which isn't right.

[chrishtr, 2014/01/14 23:33:00]

Done.

+                ruleSetAnalyzer->invalidateElementSubtreeForClassChange(newClasses[i], element);
+            else if (checker.hasSelectorForClass(newClasses[i]))
+                return true;
+        }
     }
 
     for (unsigned i = 0; i < oldClasses.size(); ++i) {
         if (remainingClassBits.quickGet(i))
             continue;
+
         // Class was removed.
-        if (checker.hasSelectorForClass(oldClasses[i]))
+        const RuleSetAnalyzer* ruleSetAnalyzer = checker.getRuleSetAnalyzer();
+        if (ruleSetAnalyzer)
+            ruleSetAnalyzer->invalidateElementSubtreeForClassChange(oldClasses[i], element);
+        else if (checker.hasSelectorForClass(oldClasses[i]))
             return true;
     }
 
@@ -1103,10 +1116,10 @@ void Element::classAttributeChanged(const AtomicString& newClassString)
         const SpaceSplitString oldClasses = ensureUniqueElementData()->classNames();
         elementData()->setClass(newClassString, shouldFoldCase);
         const SpaceSplitString& newClasses = elementData()->classNames();
-        shouldInvalidateStyle = testShouldInvalidateStyle && checkSelectorForClassChange(oldClasses, newClasses, styleResolver->ensureRuleFeatureSet());
+        shouldInvalidateStyle = testShouldInvalidateStyle && checkSelectorForClassChange(oldClasses, newClasses, styleResolver->ensureRuleFeatureSet(), this);
     } else if (elementData()) {
         const SpaceSplitString& oldClasses = elementData()->classNames();
-        shouldInvalidateStyle = testShouldInvalidateStyle && checkSelectorForClassChange(oldClasses, styleResolver->ensureRuleFeatureSet());
+        shouldInvalidateStyle = testShouldInvalidateStyle && checkSelectorForClassChange(oldClasses, styleResolver->ensureRuleFeatureSet(), this);
         elementData()->clearClass();
     }
 
@@ -1139,11 +1152,11 @@ bool Element::shouldInvalidateDistributionWhenAttributeChanged(ElementShadow* el
             const bool shouldFoldCase = document().inQuirksMode();
             const SpaceSplitString& oldClasses = elementData()->classNames();
             const SpaceSplitString newClasses(newClassString, shouldFoldCase);
-            if (checkSelectorForClassChange(oldClasses, newClasses, featureSet))
+            if (checkSelectorForClassChange(oldClasses, newClasses, featureSet, this))
                 return true;
         } else {
             const SpaceSplitString& oldClasses = elementData()->classNames();
-            if (checkSelectorForClassChange(oldClasses, featureSet))
+            if (checkSelectorForClassChange(oldClasses, featureSet, this))

[esprehn, 2014/01/14 21:32:56]

These should be methods now, don't pass |this|, just turn
checkSelectorForClassChange into a method.

[chrishtr, 2014/01/14 23:33:00]

Done.

                 return true;
         }
     }