Move StyleSheet to the oilpan heap using transition types.

Source/core/css/StyleSheetContents.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 356 matching lines @@
     return false;
 }
 
 bool StyleSheetContents::loadCompleted() const
 {
     StyleSheetContents* parentSheet = parentStyleSheet();
     if (parentSheet)
         return parentSheet->loadCompleted();
 
     StyleSheetContents* root = rootStyleSheet();
-    for (unsigned i = 0; i < root->m_clients.size(); ++i) {
-        if (!root->m_clients[i]->loadCompleted())
+    for (ClientsIterator it = root->m_clients.begin(); it != root->m_clients.end(); ++it) {
+        if (!(*it)->loadCompleted())
             return false;
     }
     return true;
 }
 
 void StyleSheetContents::checkLoaded()
 {
     if (isLoading())
         return;
 
     // Avoid |this| being deleted by scripts that run via
     // ScriptableDocumentParser::executeScriptsWaitingForResources().
     // See https://bugs.webkit.org/show_bug.cgi?id=95106
     RefPtrWillBeRawPtr<StyleSheetContents> protect(this);
 
     StyleSheetContents* parentSheet = parentStyleSheet();
     if (parentSheet) {
         parentSheet->checkLoaded();
         return;
     }
 
     StyleSheetContents* root = rootStyleSheet();
     if (root->m_clients.isEmpty())
         return;
 
-    Vector<CSSStyleSheet*> clients(root->m_clients);
-    for (unsigned i = 0; i < clients.size(); ++i) {
-        // Avoid |CSSSStyleSheet| and |ownerNode| being deleted by scripts that run via
-        // ScriptableDocumentParser::executeScriptsWaitingForResources().
-        RefPtr<CSSStyleSheet> protectClient(clients[i]);
+    // Avoid |CSSSStyleSheet| and |ownerNode| being deleted by scripts that run via

[Mads Ager (chromium), 2014/03/05 11:16:36]

The protection during iteration has changed here. The protection that was going
on here was shaky. It turned out that the last sheet in all layout tests was the
only one that had an owner and therefore the old protection worked. That is
pretty funky. Instead of protecting each element one at a time during the
iteration, we protect them all up front and let them die after the iteration.
That seems saner in any case in the current system and can be removed once we
ship with oilpan.

+    // ScriptableDocumentParser::executeScriptsWaitingForResources().
+    //
+    // FIXME: oilpan: with oilpan we do not need to protect the CSSStyleSheets
+    // explicitly during the iteration. The iterator will make the pointers
+    // strong during iteration so we can just directly iterate root->m_clients.
+    WillBeHeapHashSet<RefPtrWillBeMember<CSSStyleSheet> > protectedClients;

[Erik Corry, 2014/03/05 11:33:29]

I think this can be a vector, then you don't have to rehash and it makes the
iteration a little simpler.

Also you need to revisit the comment.

[Mads Ager (chromium), 2014/03/05 11:36:04]

Good idea, that will simplify. I have replaced it with a Vector with inline
capacity 5 and I then iterate that. Thanks.

+    for (ClientsIterator it = root->m_clients.begin(); it != root->m_clients.end(); ++it)
+        protectedClients.add(*it);
 
-        if (clients[i]->loadCompleted())
+    for (WillBeHeapHashSet<RefPtrWillBeMember<CSSStyleSheet> >::iterator it = protectedClients.begin(); it != protectedClients.end(); ++it) {
+        if ((*it)->loadCompleted())
             continue;
 
         // sheetLoaded might be invoked after its owner node is removed from document.
-        if (RefPtr<Node> ownerNode = clients[i]->ownerNode()) {
-            if (clients[i]->sheetLoaded())
+        if (RefPtr<Node> ownerNode = (*it)->ownerNode()) {
+            if ((*it)->sheetLoaded())
                 ownerNode->notifyLoadedSheetAndAllCriticalSubresources(m_didLoadErrorOccur);
         }
     }
 }
 
 void StyleSheetContents::notifyLoadedSheet(const CSSStyleSheetResource* sheet)
 {
     ASSERT(sheet);
     m_didLoadErrorOccur |= sheet->errorOccurred();
     // updateLayoutIgnorePendingStyleSheets can cause us to create the RuleSet on this
     // sheet before its imports have loaded. So clear the RuleSet when the imports
     // load since the import's subrules are flattened into its parent sheet's RuleSet.
     clearRuleSet();
 }
 
 void StyleSheetContents::startLoadingDynamicSheet()
 {
     StyleSheetContents* root = rootStyleSheet();
-    for (unsigned i = 0; i < root->m_clients.size(); ++i)
-        root->m_clients[i]->startLoadingDynamicSheet();
+    for (ClientsIterator it = root->m_clients.begin(); it != root->m_clients.end(); ++it)
+        (*it)->startLoadingDynamicSheet();
 }
 
 StyleSheetContents* StyleSheetContents::rootStyleSheet() const
 {
     const StyleSheetContents* root = this;
     while (root->parentStyleSheet())
         root = root->parentStyleSheet();
     return const_cast<StyleSheetContents*>(root);
 }
 
 bool StyleSheetContents::hasSingleOwnerNode() const
 {
     StyleSheetContents* root = rootStyleSheet();
     if (root->m_clients.isEmpty())
         return false;
     return root->m_clients.size() == 1;
 }
 
 Node* StyleSheetContents::singleOwnerNode() const
 {
     StyleSheetContents* root = rootStyleSheet();
     if (root->m_clients.isEmpty())
         return 0;
     ASSERT(root->m_clients.size() == 1);
-    return root->m_clients[0]->ownerNode();
+    return (*root->m_clients.begin())->ownerNode();
 }
 
 Document* StyleSheetContents::singleOwnerDocument() const
 {
     Node* ownerNode = singleOwnerNode();
     return ownerNode ? &ownerNode->document() : 0;
 }
 
 KURL StyleSheetContents::completeURL(const String& url) const
 {
@@ skipping 41 matching lines @@
 }
 
 StyleSheetContents* StyleSheetContents::parentStyleSheet() const
 {
     return m_ownerRule ? m_ownerRule->parentStyleSheet() : 0;
 }
 
 void StyleSheetContents::registerClient(CSSStyleSheet* sheet)
 {
     ASSERT(!m_clients.contains(sheet));
-    m_clients.append(sheet);
+    m_clients.add(sheet);
 }
 
 void StyleSheetContents::unregisterClient(CSSStyleSheet* sheet)
 {
-    size_t position = m_clients.find(sheet);
-    ASSERT(position != kNotFound);
-    m_clients.remove(position);
+    ASSERT(m_clients.contains(sheet));
+    m_clients.remove(sheet);
 }
 
 void StyleSheetContents::addedToMemoryCache()
 {
     ASSERT(!m_isInMemoryCache);
     ASSERT(isCacheable());
     m_isInMemoryCache = true;
 }
 
 void StyleSheetContents::removedFromMemoryCache()
@@ skipping 24 matching lines @@
         parentSheet->clearRuleSet();
 
     // Don't want to clear the StyleResolver if the RuleSet hasn't been created
     // since we only clear the StyleResolver so that it's members are properly
     // updated in ScopedStyleResolver::addRulesFromSheet.
     if (!m_ruleSet)
         return;
 
     // Clearing the ruleSet means we need to recreate the styleResolver data structures.
     // See the StyleResolver calls in ScopedStyleResolver::addRulesFromSheet.
-    for (size_t i = 0; i < m_clients.size(); ++i) {
-        if (Document* document = m_clients[i]->ownerDocument())
+    for (ClientsIterator it = m_clients.begin(); it != m_clients.end(); ++it) {
+        if (Document* document = (*it)->ownerDocument())
             document->styleEngine()->clearResolver();
     }
     m_ruleSet.clear();
 }
 
 void StyleSheetContents::notifyRemoveFontFaceRule(const StyleRuleFontFace* fontFaceRule)
 {
     StyleSheetContents* root = rootStyleSheet();
 
-    for (unsigned i = 0; i < root->m_clients.size(); ++i) {
-        if (Node* ownerNode = root->m_clients[0]->ownerNode())
+    for (ClientsIterator it = root->m_clients.begin(); it != root->m_clients.end(); ++it) {
+        if (Node* ownerNode = (*it)->ownerNode())
             ownerNode->document().styleEngine()->removeFontFaceRules(WillBeHeapVector<RawPtrWillBeMember<const StyleRuleFontFace> >(1, fontFaceRule));
     }
 }
 
 static void findFontFaceRulesFromRules(const WillBeHeapVector<RefPtrWillBeMember<StyleRuleBase> >& rules, WillBeHeapVector<RawPtrWillBeMember<const StyleRuleFontFace> >& fontFaceRules)
 {
     for (unsigned i = 0; i < rules.size(); ++i) {
         StyleRuleBase* rule = rules[i].get();
 
         if (rule->isFontFaceRule()) {
@@ skipping 16 matching lines @@
     }
 
     findFontFaceRulesFromRules(childRules(), fontFaceRules);
 }
 
 void StyleSheetContents::trace(Visitor* visitor)
 {
     visitor->trace(m_ownerRule);
     visitor->trace(m_importRules);
     visitor->trace(m_childRules);
+    visitor->trace(m_clients);
 }
 
 }