Cherry-pick 1ffbfef. rdar://problem/108758349

Disallow caching of StyleSheetContents that uses nesting https://bugs.webkit.org/show_bug.cgi?id=256449 rdar://108758349 Reviewed by Alan Baradlay. Mutations to cached document may affect other stylesheets. * Source/WebCore/css/CSSGroupingRule.cpp: (WebCore::CSSGroupingRule::prepareChildStyleRuleForNesting): * Source/WebCore/css/CSSStyleSheet.cpp: (WebCore::CSSStyleSheet::prepareChildStyleRuleForNesting): * Source/WebCore/css/StyleSheetContents.cpp: (WebCore::StyleSheetContents::isCacheable const): * Source/WebCore/css/StyleSheetContents.h: * Source/WebCore/css/parser/CSSParserImpl.cpp: (WebCore::CSSParserImpl::consumeRegularRuleList): (WebCore::CSSParserImpl::consumeStyleRule): Canonical link: https://commits.webkit.org/263799@main Identifier: 259548.747@safari-7615.3.3.13-branch
WebKit · May 8, 2023 · dc3172f · dc3172f
1 parent 22a068a
commit dc3172f
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Showing 5 changed files with 14 additions and 1 deletion.
diff --git a/Source/WebCore/css/CSSGroupingRule.cpp b/Source/WebCore/css/CSSGroupingRule.cpp
@@ -176,6 +176,8 @@ RefPtr<StyleRuleWithNesting> CSSGroupingRule::prepareChildStyleRuleForNesting(St
         if (rule == &styleRule) {
             auto styleRuleWithNesting = StyleRuleWithNesting::create(WTFMove(styleRule));
             rules[i] = styleRuleWithNesting.ptr();
+            if (auto* styleSheet = parentStyleSheet())
+                styleSheet->contents().setHasNestingRules();
             return styleRuleWithNesting;
         }        
     }

diff --git a/Source/WebCore/css/CSSStyleSheet.cpp b/Source/WebCore/css/CSSStyleSheet.cpp
@@ -176,6 +176,7 @@ RefPtr<StyleRuleWithNesting> CSSStyleSheet::prepareChildStyleRuleForNesting(Styl
         if (rules[i] == &styleRule) {
             auto styleRuleWithNesting = StyleRuleWithNesting::create(WTFMove(styleRule));
             rules[i] = styleRuleWithNesting.ptr();
+            m_contents->setHasNestingRules();
             return styleRuleWithNesting;
         }        
     }

diff --git a/Source/WebCore/css/StyleSheetContents.cpp b/Source/WebCore/css/StyleSheetContents.cpp
@@ -132,6 +132,8 @@ bool StyleSheetContents::isCacheable() const
     // FIXME: Valid mime type avoids the check too.
     if (!m_hasSyntacticallyValidCSSHeader)
         return false;
+    if (m_hasNestingRules)
+        return false;
     return true;
 }
 

diff --git a/Source/WebCore/css/StyleSheetContents.h b/Source/WebCore/css/StyleSheetContents.h
@@ -139,6 +139,9 @@ class StyleSheetContents final : public RefCounted<StyleSheetContents>, public C
     bool isMutable() const { return m_isMutable; }
     void setMutable() { m_isMutable = true; }
 
+    bool hasNestingRules() const { return m_hasNestingRules; }
+    void setHasNestingRules() { m_hasNestingRules = true; }
+
     bool isInMemoryCache() const { return m_inMemoryCacheCount; }
     void addedToMemoryCache();
     void removedFromMemoryCache();
@@ -177,6 +180,7 @@ class StyleSheetContents final : public RefCounted<StyleSheetContents>, public C
     bool m_didLoadErrorOccur { false };
     bool m_usesStyleBasedEditability { false };
     bool m_isMutable { false };
+    bool m_hasNestingRules { false };
     unsigned m_inMemoryCacheCount { 0 };
 
     CSSParserContext m_parserContext;

diff --git a/Source/WebCore/css/parser/CSSParserImpl.cpp b/Source/WebCore/css/parser/CSSParserImpl.cpp
@@ -589,6 +589,8 @@ Vector<RefPtr<StyleRuleBase>> CSSParserImpl::consumeRegularRuleList(CSSParserTok
                 // property declarations.
                 rules.append(createNestingParentRule());
 
+                m_styleSheet->setHasNestingRules();
+
                 if (m_observerWrapper)
                     m_observerWrapper->observer().markRuleBodyContainsImplicitlyNestedProperties();
             }
@@ -1092,8 +1094,10 @@ RefPtr<StyleRuleBase> CSSParserImpl::consumeStyleRule(CSSParserTokenRange prelud
         // We save memory by creating a simple StyleRule instead of a heavier StyleWithNestingSupportRule when we don't need the CSS Nesting features.
         if (nestedRules.isEmpty() && !selectorList->hasExplicitNestingParent() && !isNestedContext())
             styleRule = StyleRule::create(WTFMove(properties), m_context.hasDocumentSecurityOrigin, WTFMove(*selectorList));
-        else
+        else {
             styleRule = StyleRuleWithNesting::create(WTFMove(properties), m_context.hasDocumentSecurityOrigin, WTFMove(*selectorList), WTFMove(nestedRules));
+            m_styleSheet->setHasNestingRules();
+        }
     });
 
     return styleRule;