StyleResolver should update RuleSets lazily.

Source/core/css/resolver/StyleResolver.cpp

Index: Source/core/css/resolver/StyleResolver.cpp
diff --git a/Source/core/css/resolver/StyleResolver.cpp b/Source/core/css/resolver/StyleResolver.cpp
index 547c0a81ca61db86859492dadcf69ad437050a9b..71c714ff23c76b63bd992b1d0ba54ef52f8e4701 100644
--- a/Source/core/css/resolver/StyleResolver.cpp
+++ b/Source/core/css/resolver/StyleResolver.cpp
@@ -57,6 +57,8 @@
 #include "core/css/PageRuleCollector.h"
 #include "core/css/RuleSet.h"
 #include "core/css/StylePropertySet.h"
+#include "core/css/StyleRuleImport.h"
+#include "core/css/StyleSheetContents.h"
 #include "core/css/resolver/AnimatedStyleBuilder.h"
 #include "core/css/resolver/MatchResult.h"
 #include "core/css/resolver/MediaQueryResult.h"
@@ -106,6 +108,12 @@ using namespace HTMLNames;
 
 RenderStyle* StyleResolver::s_styleNotYetAvailable;
 
+inline bool isDocumentScope(const ContainerNode* scope)
+{
+    // FIXME: scope should not be null. scope should be a ShadowRoot or a Document.
+    return !scope || scope->isDocumentNode();
+}
+
 static StylePropertySet* leftToRightDeclaration()
 {
     DEFINE_STATIC_REF(MutableStylePropertySet, leftToRightDecl, (MutableStylePropertySet::create()));
@@ -126,6 +134,7 @@ StyleResolver::StyleResolver(Document& document)
     : m_document(document)
     , m_fontSelector(CSSFontSelector::create(&document))
     , m_viewportStyleResolver(ViewportStyleResolver::create(&document))
+    , m_needCollectFeatures(false)
     , m_styleResourceLoader(document.fetcher())
     , m_styleResolverStatsSequence(0)
     , m_accessCount(0)
@@ -179,6 +188,106 @@ void StyleResolver::initWatchedSelectorRules(const Vector<RefPtr<StyleRule> >& w
         m_watchedSelectorsRules->addStyleRule(watchedSelectors[i].get(), RuleHasNoSpecialState);
 }
 
+bool StyleResolver::filterViewportRules(const Vector<RefPtr<StyleRuleBase> >& rules)
+{
+    bool needsResolveViewport = false;
+
+    for (unsigned i = 0; i < rules.size(); ++i) {
+        StyleRuleBase* rule = rules[i].get();
+
+        if (rule->isViewportRule()) {
+            m_styleTree.ensureScopedStyleResolver(m_document)->addViewportRule(toStyleRuleViewport(rule));
+            needsResolveViewport = true;
+        } else if (rule->isMediaRule()) {
+            const StyleRuleMedia* mediaRule = toStyleRuleMedia(rule);
+            if ((!mediaRule->mediaQueries() || m_medium->eval(mediaRule->mediaQueries(), viewportDependentMediaQueryResults()))) {
+                if (filterViewportRules(mediaRule->childRules()))
+                    needsResolveViewport = true;
+            }
+        }
+    }
+    return needsResolveViewport;
+}
+
+bool StyleResolver::filterViewportRulesFromSheet(StyleSheetContents* sheet)
+{
+    if (!sheet)
+        return false;
+
+    bool needsResolveViewport = false;
+    const Vector<RefPtr<StyleRuleImport> >& importRules = sheet->importRules();
+    for (unsigned i = 0; i < importRules.size(); ++i) {
+        StyleRuleImport* importRule = importRules[i].get();
+        if (filterViewportRulesFromSheet(importRule->styleSheet()))
+            needsResolveViewport = true;
+    }
+
+    if (filterViewportRules(sheet->childRules()))
+        needsResolveViewport = true;
+    return needsResolveViewport;
+}
+
+bool StyleResolver::filterViewportRulesFromAuthorStyleSheets(unsigned firstNew, const Vector<RefPtr<CSSStyleSheet> >& styleSheets)
+{
+    bool needsResolveViewport = false;
+
+    unsigned size = styleSheets.size();
+    for (unsigned i = firstNew; i < size; ++i) {
+        CSSStyleSheet* cssSheet = styleSheets[i].get();
+        ASSERT(!cssSheet->disabled());
+        if (cssSheet->mediaQueries() && !m_medium->eval(cssSheet->mediaQueries(), &m_viewportDependentMediaQueryResults))
+            continue;
+        if (cssSheet->ownerNode()->isInShadowTree() || !isDocumentScope(ScopedStyleResolver::scopingNodeFor(cssSheet)))
+            continue;
+        if (filterViewportRulesFromSheet(cssSheet->contents()))
+            needsResolveViewport = true;
+    }
+    return needsResolveViewport;
+}
+
+void StyleResolver::lazyAppendAuthorStyleSheets(unsigned firstNew, const Vector<RefPtr<CSSStyleSheet> >& styleSheets)
+{
+    // FIXME: Currently We cannot lazy apppend stylesheets if the sheets have @viewport rules.
+    // Need to find the best place to update pending stylesheets for "viewport" rules.
+    bool needsResolveViewport = filterViewportRulesFromAuthorStyleSheets(firstNew, styleSheets);
+
+    unsigned size = styleSheets.size();
+    for (unsigned i = firstNew; i < size; ++i)
+        m_pendingStyleSheets.add(styleSheets[i].get());
+
+    if (needsResolveViewport)
+        collectViewportRules();
+}
+
+void StyleResolver::removePendingAuthorStyleSheets(const Vector<RefPtr<CSSStyleSheet> >& styleSheets)
+{
+    for (unsigned i = 0; i < styleSheets.size(); ++i)
+        m_pendingStyleSheets.remove(styleSheets[i].get());
+}
+
+void StyleResolver::appendPendingAuthorStyleSheets()
+{
+    setBuildScopedStyleTreeInDocumentOrder(false);
+    for (ListHashSet<CSSStyleSheet*, 16>::iterator it = m_pendingStyleSheets.begin(); it != m_pendingStyleSheets.end(); ++it) {

[ojan, 2013/11/19 17:35:05]

Is it safe for StyleResolver to hold raw pointers to CSSStyleSheets like this?
What happens if you append a stylesheet to the document and then remove it
before we've processed the pending sheets? Won't that use-after-free?

+        CSSStyleSheet* cssSheet = *it;
+        ASSERT(!cssSheet->disabled());
+        if (cssSheet->mediaQueries() && !m_medium->eval(cssSheet->mediaQueries(), &m_viewportDependentMediaQueryResults))
+            continue;
+
+        StyleSheetContents* sheet = cssSheet->contents();
+        ContainerNode* scopingNode = ScopedStyleResolver::scopingNodeFor(cssSheet);
+        if (!scopingNode && cssSheet->ownerNode() && cssSheet->ownerNode()->isInShadowTree())
+            continue;
+
+        ScopedStyleResolver* resolver = ensureScopedStyleResolver(scopingNode);
+        ASSERT(resolver);
+        resolver->addRulesFromSheet(sheet, *m_medium, this, true);
+        m_inspectorCSSOMWrappers.collectFromStyleSheetIfNeeded(cssSheet);
+    }
+    m_pendingStyleSheets.clear();
+    finishAppendAuthorStyleSheets();
+}
+
 void StyleResolver::appendAuthorStyleSheets(unsigned firstNew, const Vector<RefPtr<CSSStyleSheet> >& styleSheets)
 {
     // This handles sheets added to the end of the stylesheet list only. In other cases the style resolver
@@ -197,7 +306,7 @@ void StyleResolver::appendAuthorStyleSheets(unsigned firstNew, const Vector<RefP
 
         ScopedStyleResolver* resolver = ensureScopedStyleResolver(scopingNode);
         ASSERT(resolver);
-        resolver->addRulesFromSheet(sheet, *m_medium, this);
+        resolver->addRulesFromSheet(sheet, *m_medium, this, false);
         m_inspectorCSSOMWrappers.collectFromStyleSheetIfNeeded(cssSheet);
     }
 }
@@ -210,6 +319,17 @@ void StyleResolver::finishAppendAuthorStyleSheets()
         document().renderer()->style()->font().update(fontSelector());
 
     collectViewportRules();
+
+    document().styleEngine()->resetCSSFeatureFlags(m_features);
+}
+
+void StyleResolver::resetRuleFeatures()
+{
+    // Need to recreate RuleFeatureSet.
+    m_features.clear();
+    m_siblingRuleSet.clear();
+    m_uncommonAttributeRuleSet.clear();
+    m_needCollectFeatures = true;
 }
 
 void StyleResolver::addTreeBoundaryCrossingRules(const Vector<MinimalRuleData>& rules, ContainerNode* scope)
@@ -272,6 +392,7 @@ void StyleResolver::resetAuthorStyle(const ContainerNode* scopingNode)
     treeBoundaryCrossingRules().reset(scopingNode);
 
     resolver->resetAuthorStyle();
+    resetRuleFeatures();
     if (!scopingNode)
         return;
 
@@ -334,6 +455,7 @@ void StyleResolver::collectFeatures()
 
     m_siblingRuleSet = makeRuleSet(m_features.siblingRules);
     m_uncommonAttributeRuleSet = makeRuleSet(m_features.uncommonAttributeRules);
+    m_needCollectFeatures = false;
 }
 
 bool StyleResolver::hasRulesForId(const AtomicString& id) const
@@ -662,6 +784,8 @@ PassRefPtr<RenderStyle> StyleResolver::styleForElement(Element* element, RenderS
 {
     ASSERT(document().frame());
     ASSERT(documentSettings());
+    ASSERT(!hasPendingAuthorStyleSheets());
+    ASSERT(!m_needCollectFeatures);
 
     // Once an element has a renderer, we don't try to destroy it, since otherwise the renderer
     // will vanish if a style recalc happens during loading.
@@ -755,6 +879,7 @@ PassRefPtr<RenderStyle> StyleResolver::styleForKeyframe(Element* e, const Render
 {
     ASSERT(document().frame());
     ASSERT(documentSettings());
+    ASSERT(!hasPendingAuthorStyleSheets());
 
     if (e == document().documentElement())
         resetDirectionAndWritingModeOnDocument(document());
@@ -814,6 +939,7 @@ void StyleResolver::keyframeStylesForAnimation(Element* e, const RenderStyle& el
     if (!e || list.animationName().isEmpty())
         return;
 
+    ASSERT(!hasPendingAuthorStyleSheets());
     const StyleRuleKeyframes* keyframesRule = CSSAnimations::matchScopedKeyframesRule(this, e, list.animationName().impl());
     if (!keyframesRule)
         return;
@@ -922,6 +1048,7 @@ PassRefPtr<RenderStyle> StyleResolver::pseudoStyleForElement(Element* e, const P
 
 PassRefPtr<RenderStyle> StyleResolver::styleForPage(int pageIndex)
 {
+    ASSERT(!hasPendingAuthorStyleSheets());
     resetDirectionAndWritingModeOnDocument(document());
     StyleResolverState state(document(), document().documentElement()); // m_rootElementStyle will be set to the document style.