[CSS] CSSSelectorList class should have a const_iterator

https://bugs.webkit.org/show_bug.cgi?id=271672 rdar://125373236 Reviewed by Antti Koivisto. CSSSelectorList is an optimized contiguous memory representation of a list. This patch adds a forward const iterator interface to it to be able to use range based for-loop. * Source/WebCore/css/CSSSelectorList.cpp: (WebCore::forEachTagSelector): (WebCore::forEachSelector): (WebCore::CSSSelectorList::hasExplicitNestingParent const): * Source/WebCore/css/CSSSelectorList.h: (WebCore::CSSSelectorList::const_iterator::operator* const): (WebCore::CSSSelectorList::const_iterator::operator-> const): (WebCore::CSSSelectorList::const_iterator::operator!= const): (WebCore::CSSSelectorList::const_iterator::const_iterator): (WebCore::CSSSelectorList::const_iterator::operator++): (WebCore::CSSSelectorList::begin const): (WebCore::CSSSelectorList::end const): * Source/WebCore/cssjit/SelectorCompiler.cpp: (WebCore::SelectorCompiler::addNthChildType): (WebCore::SelectorCompiler::addPseudoClassType): Canonical link: https://commits.webkit.org/276697@main
WebKit · Mar 26, 2024 · ade1396 · ade1396
1 parent 0827d78
commit ade1396
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Showing 3 changed files with 37 additions and 12 deletions.
diff --git a/Source/WebCore/css/CSSSelectorList.cpp b/Source/WebCore/css/CSSSelectorList.cpp
@@ -132,8 +132,8 @@ static bool forEachTagSelector(Functor& functor, const CSSSelector* selector)
         if (functor(selector))
             return true;
         if (const CSSSelectorList* selectorList = selector->selectorList()) {
-            for (const CSSSelector* subSelector = selectorList->first(); subSelector; subSelector = CSSSelectorList::next(subSelector)) {
-                if (forEachTagSelector(functor, subSelector))
+            for (const auto& subSelector : *selectorList) {
+                if (forEachTagSelector(functor, &subSelector))
                     return true;
             }
         }
@@ -143,10 +143,10 @@ static bool forEachTagSelector(Functor& functor, const CSSSelector* selector)
 }
 
 template <typename Functor>
-static bool forEachSelector(Functor& functor, const CSSSelectorList* selectorList)
+static bool forEachSelector(Functor& functor, const CSSSelectorList& selectorList)
 {
-    for (const CSSSelector* selector = selectorList->first(); selector; selector = CSSSelectorList::next(selector)) {
-        if (forEachTagSelector(functor, selector))
+    for (const auto& selector : selectorList) {
+        if (forEachTagSelector(functor, &selector))
             return true;
     }
 
@@ -159,7 +159,7 @@ bool CSSSelectorList::hasExplicitNestingParent() const
         return selector->hasExplicitNestingParent();
     };
 
-    return forEachSelector(functor, this);
+    return forEachSelector(functor, *this);
 }
 
 bool CSSSelectorList::hasOnlyNestingSelector() const

diff --git a/Source/WebCore/css/CSSSelectorList.h b/Source/WebCore/css/CSSSelectorList.h
@@ -26,6 +26,7 @@
 #pragma once
 
 #include "CSSSelector.h"
+#include <iterator>
 #include <memory>
 #include <wtf/UniqueArray.h>
 
@@ -58,6 +59,29 @@ class CSSSelectorList {
         return current - m_selectorArray.get();
     }
 
+    struct const_iterator {
+        friend class CSSSelectorList;
+        using value_type = CSSSelector;
+        using difference_type = std::ptrdiff_t;
+        using pointer = const CSSSelector*;
+        using reference = const CSSSelector&;
+        using iterator_category = std::forward_iterator_tag;
+        reference operator*() const { return *m_ptr; }
+        pointer operator->() const { return m_ptr; }
+        bool operator!=(const const_iterator& other) const { return m_ptr != other.m_ptr; }
+        const_iterator() = default;
+        const_iterator(pointer ptr) : m_ptr(ptr) { };
+        const_iterator& operator++()
+        {
+            m_ptr = CSSSelectorList::next(m_ptr);
+            return *this;
+        }
+    private:
+        pointer m_ptr = nullptr;
+    };
+    const_iterator begin() const { return { first() }; };
+    const_iterator end() const { return { }; }
+
     bool hasExplicitNestingParent() const;
     bool hasOnlyNestingSelector() const;
 

diff --git a/Source/WebCore/cssjit/SelectorCompiler.cpp b/Source/WebCore/cssjit/SelectorCompiler.cpp
@@ -709,14 +709,14 @@ static FunctionType addNthChildType(const CSSSelector& selector, SelectorContext
             globalFunctionType = FunctionType::SelectorCheckerWithCheckingContext;
 
         SelectorFragmentList* selectorFragments = nullptr;
-        for (const CSSSelector* subselector = selectorList->first(); subselector; subselector = CSSSelectorList::next(subselector)) {
+        for (const auto& subselector : *selectorList) {
             if (!selectorFragments) {
                 nthChildOfSelectorInfo.selectorList.append(SelectorFragmentList());
                 selectorFragments = &nthChildOfSelectorInfo.selectorList.last();
             }
 
             VisitedMode ignoreVisitedMode = VisitedMode::None;
-            FunctionType functionType = constructFragments(subselector, selectorContext, *selectorFragments, FragmentsLevel::InFunctionalPseudoType, positionInRootFragments, visitedMatchEnabled, ignoreVisitedMode, PseudoElementMatchingBehavior::NeverMatch);
+            FunctionType functionType = constructFragments(&subselector, selectorContext, *selectorFragments, FragmentsLevel::InFunctionalPseudoType, positionInRootFragments, visitedMatchEnabled, ignoreVisitedMode, PseudoElementMatchingBehavior::NeverMatch);
             ASSERT_WITH_MESSAGE(ignoreVisitedMode == VisitedMode::None, ":visited is disabled in the functional pseudo classes");
             switch (functionType) {
             case FunctionType::SimpleSelectorChecker:
@@ -1261,14 +1261,14 @@ static inline FunctionType addPseudoClassType(const CSSSelector& selector, Selec
 
             FunctionType functionType = FunctionType::SimpleSelectorChecker;
             SelectorFragmentList* selectorFragments = nullptr;
-            for (const CSSSelector* subselector = selectorList->first(); subselector; subselector = CSSSelectorList::next(subselector)) {
+            for (const auto& subselector : *selectorList) {
                 if (!selectorFragments) {
                     fragment.notFilters.append(SelectorFragmentList());
                     selectorFragments = &fragment.notFilters.last();
                 }
 
                 VisitedMode ignoreVisitedMode = VisitedMode::None;
-                FunctionType localFunctionType = constructFragments(subselector, selectorContext, *selectorFragments, FragmentsLevel::InFunctionalPseudoType, positionInRootFragments, visitedMatchEnabled, ignoreVisitedMode, PseudoElementMatchingBehavior::NeverMatch);
+                FunctionType localFunctionType = constructFragments(&subselector, selectorContext, *selectorFragments, FragmentsLevel::InFunctionalPseudoType, positionInRootFragments, visitedMatchEnabled, ignoreVisitedMode, PseudoElementMatchingBehavior::NeverMatch);
                 ASSERT_WITH_MESSAGE(ignoreVisitedMode == VisitedMode::None, ":visited is disabled in the functional pseudo classes");
 
                 // Since this is not pseudo class filter, CannotMatchAnything implies this filter always passes.
@@ -1312,16 +1312,17 @@ static inline FunctionType addPseudoClassType(const CSSSelector& selector, Selec
         {
             SelectorList matchesList;
             const CSSSelectorList* selectorList = selector.selectorList();
+            ASSERT(selectorList);
             FunctionType functionType = FunctionType::SimpleSelectorChecker;
             SelectorFragmentList* selectorFragments = nullptr;
-            for (const CSSSelector* subselector = selectorList->first(); subselector; subselector = CSSSelectorList::next(subselector)) {
+            for (const auto& subselector : *selectorList) {
                 if (!selectorFragments) {
                     matchesList.append(SelectorFragmentList());
                     selectorFragments = &matchesList.last();
                 }
 
                 VisitedMode ignoreVisitedMode = VisitedMode::None;
-                FunctionType localFunctionType = constructFragments(subselector, selectorContext, *selectorFragments, FragmentsLevel::InFunctionalPseudoType, positionInRootFragments, visitedMatchEnabled, ignoreVisitedMode, pseudoElementMatchingBehavior);
+                FunctionType localFunctionType = constructFragments(&subselector, selectorContext, *selectorFragments, FragmentsLevel::InFunctionalPseudoType, positionInRootFragments, visitedMatchEnabled, ignoreVisitedMode, pseudoElementMatchingBehavior);
                 ASSERT_WITH_MESSAGE(ignoreVisitedMode == VisitedMode::None, ":visited is disabled in the functional pseudo classes");
 
                 // Since this fragment never matches against the element, don't insert it to matchesList.