Source/core/dom/StyleEngine.cpp

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
m_fontSelector
detachFromDocument
master
insertTreeScopeInDocumentOrder
ensureStyleSheetCollectionFor
styleSheetCollectionFor
styleSheetsForStyleSheetList
activeAuthorStyleSheets
combineCSSFeatureFlags
resetCSSFeatureFlags
injectedAuthorStyleSheets
updateInjectedStyleSheetCache
invalidateInjectedStyleSheetCache
addAuthorSheet
addPendingSheet
removePendingSheet
modifiedStyleSheet
addStyleSheetCandidateNode
removeStyleSheetCandidateNode
removeStyleSheetCandidateNode
modifiedStyleSheetCandidateNode
shouldUpdateShadowTreeStyleSheetCollection
clearMediaQueryRuleSetOnTreeScopeStyleSheets
clearMediaQueryRuleSetStyleSheets
updateStyleSheetsInImport
updateActiveStyleSheets
activeStyleSheetsForInspector
didRemoveShadowRoot
appendActiveAuthorStyleSheets
createResolver
clearResolver
clearMasterResolver
resolverAccessCount
didDetach
shouldClearResolver
resolverChanged
clearFontCache
updateGenericFontFamilySettings
removeFontFaceRules
markTreeScopeDirty
markDocumentDirty
isCacheableForStyleElement
createSheet
parseSheet
removeSheet
trace
/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2001 Dirk Mueller (mueller@kde.org)
 *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) Research In Motion Limited 2010-2011. 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,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "core/dom/StyleEngine.h"

#include "HTMLNames.h"
#include "SVGNames.h"
#include "core/css/CSSFontSelector.h"
#include "core/css/CSSStyleSheet.h"
#include "core/css/FontFaceCache.h"
#include "core/css/StyleSheetContents.h"
#include "core/dom/DocumentStyleSheetCollector.h"
#include "core/dom/Element.h"
#include "core/dom/ProcessingInstruction.h"
#include "core/dom/ShadowTreeStyleSheetCollection.h"
#include "core/dom/shadow/ShadowRoot.h"
#include "core/html/HTMLIFrameElement.h"
#include "core/html/HTMLLinkElement.h"
#include "core/html/imports/HTMLImport.h"
#include "core/inspector/InspectorInstrumentation.h"
#include "core/page/InjectedStyleSheets.h"
#include "core/page/Page.h"
#include "core/frame/Settings.h"
#include "core/svg/SVGStyleElement.h"
#include "platform/URLPatternMatcher.h"

namespace WebCore {

using namespace HTMLNames;

StyleEngine::StyleEngine(Document& document)
    : m_document(document)
    , m_isMaster(HTMLImport::isMaster(&document))
    , m_pendingStylesheets(0)
    , m_injectedStyleSheetCacheValid(false)
    , m_documentStyleSheetCollection(document)
    , m_documentScopeDirty(true)
    , m_usesSiblingRules(false)
    , m_usesSiblingRulesOverride(false)
    , m_usesFirstLineRules(false)
    , m_usesFirstLetterRules(false)
    , m_usesRemUnits(false)
    , m_maxDirectAdjacentSelectors(0)
    , m_ignorePendingStylesheets(false)
    , m_didCalculateResolver(false)
    // We don't need to create CSSFontSelector for imported document or
    // HTMLTemplateElement's document, because those documents have no frame.
    , m_fontSelector(document.frame() ? CSSFontSelector::create(&document) : nullptr)
{
}

StyleEngine::~StyleEngine()
{
}

void StyleEngine::detachFromDocument()
{
    // Cleanup is performed eagerly when the StyleEngine is removed from the
    // document. The StyleEngine is unreachable after this, since only the
    // document has a reference to it.
    for (unsigned i = 0; i < m_injectedAuthorStyleSheets.size(); ++i)
        m_injectedAuthorStyleSheets[i]->clearOwnerNode();
    for (unsigned i = 0; i < m_authorStyleSheets.size(); ++i)
        m_authorStyleSheets[i]->clearOwnerNode();

    if (m_fontSelector) {
        m_fontSelector->clearDocument();
#if !ENABLE(OILPAN)
        if (m_resolver)
            m_fontSelector->unregisterForInvalidationCallbacks(m_resolver.get());
#endif
    }

    // Decrement reference counts for things we could be keeping alive.
    m_fontSelector.clear();
    m_resolver.clear();
    m_styleSheetCollectionMap.clear();
}

inline Document* StyleEngine::master()
{
    if (isMaster())
        return &m_document;
    HTMLImport* import = m_document.import();
    if (!import) // Document::import() can return null while executing its destructor.
        return 0;
    return import->master();
}

void StyleEngine::insertTreeScopeInDocumentOrder(TreeScopeSet& treeScopes, TreeScope* treeScope)
{
    if (treeScopes.isEmpty()) {
        treeScopes.add(treeScope);
        return;
    }
    if (treeScopes.contains(treeScope))
        return;

    TreeScopeSet::iterator begin = treeScopes.begin();
    TreeScopeSet::iterator end = treeScopes.end();
    TreeScopeSet::iterator it = end;
    TreeScope* followingTreeScope = 0;
    do {
        --it;
        TreeScope* n = *it;
        unsigned short position = n->comparePosition(*treeScope);
        if (position & Node::DOCUMENT_POSITION_FOLLOWING) {
            treeScopes.insertBefore(followingTreeScope, treeScope);
            return;
        }
        followingTreeScope = n;
    } while (it != begin);

    treeScopes.insertBefore(followingTreeScope, treeScope);
}

TreeScopeStyleSheetCollection* StyleEngine::ensureStyleSheetCollectionFor(TreeScope& treeScope)
{
    if (treeScope == m_document)
        return &m_documentStyleSheetCollection;

    WillBeHeapHashMap<TreeScope*, OwnPtrWillBeMember<ShadowTreeStyleSheetCollection> >::AddResult result = m_styleSheetCollectionMap.add(&treeScope, nullptr);
    if (result.isNewEntry)
        result.storedValue->value = adoptPtrWillBeNoop(new ShadowTreeStyleSheetCollection(toShadowRoot(treeScope)));
    return result.storedValue->value.get();
}

TreeScopeStyleSheetCollection* StyleEngine::styleSheetCollectionFor(TreeScope& treeScope)
{
    if (treeScope == m_document)
        return &m_documentStyleSheetCollection;

    WillBeHeapHashMap<TreeScope*, OwnPtrWillBeMember<ShadowTreeStyleSheetCollection> >::iterator it = m_styleSheetCollectionMap.find(&treeScope);
    if (it == m_styleSheetCollectionMap.end())
        return 0;
    return it->value.get();
}

const WillBeHeapVector<RefPtrWillBeMember<StyleSheet> >& StyleEngine::styleSheetsForStyleSheetList(TreeScope& treeScope)
{
    if (treeScope == m_document)
        return m_documentStyleSheetCollection.styleSheetsForStyleSheetList();

    return ensureStyleSheetCollectionFor(treeScope)->styleSheetsForStyleSheetList();
}

const WillBeHeapVector<RefPtrWillBeMember<CSSStyleSheet> >& StyleEngine::activeAuthorStyleSheets() const
{
    return m_documentStyleSheetCollection.activeAuthorStyleSheets();
}

void StyleEngine::combineCSSFeatureFlags(const RuleFeatureSet& features)
{
    // Delay resetting the flags until after next style recalc since unapplying the style may not work without these set (this is true at least with before/after).
    m_usesSiblingRules = m_usesSiblingRules || features.usesSiblingRules();
    m_usesFirstLineRules = m_usesFirstLineRules || features.usesFirstLineRules();
    m_maxDirectAdjacentSelectors = max(m_maxDirectAdjacentSelectors, features.maxDirectAdjacentSelectors());
}

void StyleEngine::resetCSSFeatureFlags(const RuleFeatureSet& features)
{
    m_usesSiblingRules = features.usesSiblingRules();
    m_usesFirstLineRules = features.usesFirstLineRules();
    m_maxDirectAdjacentSelectors = features.maxDirectAdjacentSelectors();
}

const WillBeHeapVector<RefPtrWillBeMember<CSSStyleSheet> >& StyleEngine::injectedAuthorStyleSheets() const
{
    updateInjectedStyleSheetCache();
    return m_injectedAuthorStyleSheets;
}

void StyleEngine::updateInjectedStyleSheetCache() const
{
    if (m_injectedStyleSheetCacheValid)
        return;
    m_injectedStyleSheetCacheValid = true;
    m_injectedAuthorStyleSheets.clear();

    Page* owningPage = m_document.page();
    if (!owningPage)
        return;

    const InjectedStyleSheetEntryVector& entries = InjectedStyleSheets::instance().entries();
    for (unsigned i = 0; i < entries.size(); ++i) {
        const InjectedStyleSheetEntry* entry = entries[i].get();
        if (entry->injectedFrames() == InjectStyleInTopFrameOnly && m_document.ownerElement())
            continue;
        if (!URLPatternMatcher::matchesPatterns(m_document.url(), entry->whitelist()))
            continue;
        RefPtrWillBeRawPtr<CSSStyleSheet> groupSheet = CSSStyleSheet::createInline(const_cast<Document*>(&m_document), KURL());
        m_injectedAuthorStyleSheets.append(groupSheet);
        groupSheet->contents()->parseString(entry->source());
    }
}

void StyleEngine::invalidateInjectedStyleSheetCache()
{
    m_injectedStyleSheetCacheValid = false;
    markDocumentDirty();
    // FIXME: updateInjectedStyleSheetCache is called inside StyleSheetCollection::updateActiveStyleSheets
    // and batch updates lots of sheets so we can't call addedStyleSheet() or removedStyleSheet().
    m_document.styleResolverChanged(RecalcStyleDeferred);
}

void StyleEngine::addAuthorSheet(PassRefPtrWillBeRawPtr<StyleSheetContents> authorSheet)
{
    m_authorStyleSheets.append(CSSStyleSheet::create(authorSheet, &m_document));
    m_document.addedStyleSheet(m_authorStyleSheets.last().get(), RecalcStyleImmediately);
    markDocumentDirty();
}

void StyleEngine::addPendingSheet()
{
    m_pendingStylesheets++;
}

// This method is called whenever a top-level stylesheet has finished loading.
void StyleEngine::removePendingSheet(Node* styleSheetCandidateNode, RemovePendingSheetNotificationType notification)
{
    ASSERT(styleSheetCandidateNode);
    TreeScope* treeScope = isHTMLStyleElement(*styleSheetCandidateNode) ? &styleSheetCandidateNode->treeScope() : &m_document;
    markTreeScopeDirty(*treeScope);

    // Make sure we knew this sheet was pending, and that our count isn't out of sync.
    ASSERT(m_pendingStylesheets > 0);

    m_pendingStylesheets--;
    if (m_pendingStylesheets)
        return;

    if (notification == RemovePendingSheetNotifyLater) {
        m_document.setNeedsNotifyRemoveAllPendingStylesheet();
        return;
    }

    // FIXME: We can't call addedStyleSheet or removedStyleSheet here because we don't know
    // what's new. We should track that to tell the style system what changed.
    m_document.didRemoveAllPendingStylesheet();
}

void StyleEngine::modifiedStyleSheet(StyleSheet* sheet)
{
    if (!sheet)
        return;

    Node* node = sheet->ownerNode();
    if (!node || !node->inDocument())
        return;

    TreeScope& treeScope = isHTMLStyleElement(*node) ? node->treeScope() : m_document;
    ASSERT(isHTMLStyleElement(node) || treeScope == m_document);

    markTreeScopeDirty(treeScope);
}

void StyleEngine::addStyleSheetCandidateNode(Node* node, bool createdByParser)
{
    if (!node->inDocument())
        return;

    TreeScope& treeScope = isHTMLStyleElement(*node) ? node->treeScope() : m_document;
    ASSERT(isHTMLStyleElement(node) || treeScope == m_document);

    TreeScopeStyleSheetCollection* collection = ensureStyleSheetCollectionFor(treeScope);
    ASSERT(collection);
    collection->addStyleSheetCandidateNode(node, createdByParser);

    markTreeScopeDirty(treeScope);
    if (treeScope != m_document)
        insertTreeScopeInDocumentOrder(m_activeTreeScopes, &treeScope);
}

void StyleEngine::removeStyleSheetCandidateNode(Node* node)
{
    removeStyleSheetCandidateNode(node, 0, m_document);
}

void StyleEngine::removeStyleSheetCandidateNode(Node* node, ContainerNode* scopingNode, TreeScope& treeScope)
{
    ASSERT(isHTMLStyleElement(node) || treeScope == m_document);

    TreeScopeStyleSheetCollection* collection = styleSheetCollectionFor(treeScope);
    ASSERT(collection);
    collection->removeStyleSheetCandidateNode(node, scopingNode);

    markTreeScopeDirty(treeScope);
    m_activeTreeScopes.remove(&treeScope);
}

void StyleEngine::modifiedStyleSheetCandidateNode(Node* node)
{
    if (!node->inDocument())
        return;

    TreeScope& treeScope = isHTMLStyleElement(*node) ? node->treeScope() : m_document;
    ASSERT(isHTMLStyleElement(node) || treeScope == m_document);
    markTreeScopeDirty(treeScope);
}

bool StyleEngine::shouldUpdateShadowTreeStyleSheetCollection(StyleResolverUpdateMode updateMode)
{
    return !m_dirtyTreeScopes.isEmpty() || updateMode == FullStyleUpdate;
}

void StyleEngine::clearMediaQueryRuleSetOnTreeScopeStyleSheets(TreeScopeSet treeScopes)
{
    for (TreeScopeSet::iterator it = treeScopes.begin(); it != treeScopes.end(); ++it) {
        TreeScope& treeScope = **it;
        ASSERT(treeScope != m_document);
        ShadowTreeStyleSheetCollection* collection = static_cast<ShadowTreeStyleSheetCollection*>(styleSheetCollectionFor(treeScope));
        ASSERT(collection);
        collection->clearMediaQueryRuleSetStyleSheets();
    }
}

void StyleEngine::clearMediaQueryRuleSetStyleSheets()
{
    m_documentStyleSheetCollection.clearMediaQueryRuleSetStyleSheets();
    clearMediaQueryRuleSetOnTreeScopeStyleSheets(m_activeTreeScopes);
    clearMediaQueryRuleSetOnTreeScopeStyleSheets(m_dirtyTreeScopes);
}

void StyleEngine::updateStyleSheetsInImport(DocumentStyleSheetCollector& parentCollector)
{
    ASSERT(!isMaster());
    WillBeHeapVector<RefPtrWillBeMember<StyleSheet> > sheetsForList;
    ImportedDocumentStyleSheetCollector subcollector(parentCollector, sheetsForList);
    m_documentStyleSheetCollection.collectStyleSheets(this, subcollector);
    m_documentStyleSheetCollection.swapSheetsForSheetList(sheetsForList);
}

bool StyleEngine::updateActiveStyleSheets(StyleResolverUpdateMode updateMode)
{
    ASSERT(isMaster());
    ASSERT(!m_document.inStyleRecalc());

    if (!m_document.isActive())
        return false;

    bool requiresFullStyleRecalc = false;
    if (m_documentScopeDirty || updateMode == FullStyleUpdate)
        requiresFullStyleRecalc = m_documentStyleSheetCollection.updateActiveStyleSheets(this, updateMode);

    if (shouldUpdateShadowTreeStyleSheetCollection(updateMode)) {
        TreeScopeSet treeScopes = updateMode == FullStyleUpdate ? m_activeTreeScopes : m_dirtyTreeScopes;
        HashSet<TreeScope*> treeScopesRemoved;

        for (TreeScopeSet::iterator it = treeScopes.begin(); it != treeScopes.end(); ++it) {
            TreeScope* treeScope = *it;
            ASSERT(treeScope != m_document);
            ShadowTreeStyleSheetCollection* collection = static_cast<ShadowTreeStyleSheetCollection*>(styleSheetCollectionFor(*treeScope));
            ASSERT(collection);
            collection->updateActiveStyleSheets(this, updateMode);
            if (!collection->hasStyleSheetCandidateNodes())
                treeScopesRemoved.add(treeScope);
        }
        if (!treeScopesRemoved.isEmpty())
            for (HashSet<TreeScope*>::iterator it = treeScopesRemoved.begin(); it != treeScopesRemoved.end(); ++it)
                m_activeTreeScopes.remove(*it);
    }

    InspectorInstrumentation::activeStyleSheetsUpdated(&m_document);
    m_usesRemUnits = m_documentStyleSheetCollection.usesRemUnits();

    m_dirtyTreeScopes.clear();
    m_documentScopeDirty = false;

    return requiresFullStyleRecalc;
}

const WillBeHeapVector<RefPtrWillBeMember<StyleSheet> > StyleEngine::activeStyleSheetsForInspector() const
{
    if (m_activeTreeScopes.isEmpty())
        return m_documentStyleSheetCollection.styleSheetsForStyleSheetList();

    WillBeHeapVector<RefPtrWillBeMember<StyleSheet> > activeStyleSheets;

    activeStyleSheets.appendVector(m_documentStyleSheetCollection.styleSheetsForStyleSheetList());

    TreeScopeSet::const_iterator begin = m_activeTreeScopes.begin();
    TreeScopeSet::const_iterator end = m_activeTreeScopes.end();
    for (TreeScopeSet::const_iterator it = begin; it != end; ++it) {
        if (TreeScopeStyleSheetCollection* collection = m_styleSheetCollectionMap.get(*it))
            activeStyleSheets.appendVector(collection->styleSheetsForStyleSheetList());
    }

    // FIXME: Inspector needs a vector which has all active stylesheets.
    // However, creating such a large vector might cause performance regression.
    // Need to implement some smarter solution.
    return activeStyleSheets;
}

void StyleEngine::didRemoveShadowRoot(ShadowRoot* shadowRoot)
{
    m_styleSheetCollectionMap.remove(shadowRoot);
}

void StyleEngine::appendActiveAuthorStyleSheets()
{
    ASSERT(isMaster());

    m_resolver->setBuildScopedStyleTreeInDocumentOrder(true);
    m_resolver->appendAuthorStyleSheets(0, m_documentStyleSheetCollection.activeAuthorStyleSheets());

    TreeScopeSet::iterator begin = m_activeTreeScopes.begin();
    TreeScopeSet::iterator end = m_activeTreeScopes.end();
    for (TreeScopeSet::iterator it = begin; it != end; ++it) {
        if (TreeScopeStyleSheetCollection* collection = m_styleSheetCollectionMap.get(*it)) {
            m_resolver->setBuildScopedStyleTreeInDocumentOrder(!collection->scopingNodesForStyleScoped());
            m_resolver->appendAuthorStyleSheets(0, collection->activeAuthorStyleSheets());
        }
    }
    m_resolver->finishAppendAuthorStyleSheets();
    m_resolver->setBuildScopedStyleTreeInDocumentOrder(false);
}

void StyleEngine::createResolver()
{
    // It is a programming error to attempt to resolve style on a Document
    // which is not in a frame. Code which hits this should have checked
    // Document::isActive() before calling into code which could get here.

    ASSERT(m_document.frame());
    ASSERT(m_fontSelector);

    m_resolver = adoptPtrWillBeNoop(new StyleResolver(m_document));
    appendActiveAuthorStyleSheets();
    m_fontSelector->registerForInvalidationCallbacks(m_resolver.get());
    combineCSSFeatureFlags(m_resolver->ensureUpdatedRuleFeatureSet());
}

void StyleEngine::clearResolver()
{
    ASSERT(!m_document.inStyleRecalc());
    ASSERT(isMaster() || !m_resolver);
    ASSERT(m_fontSelector || !m_resolver);
    if (m_resolver) {
        m_document.updateStyleInvalidationIfNeeded();
#if !ENABLE(OILPAN)
        m_fontSelector->unregisterForInvalidationCallbacks(m_resolver.get());
#endif
    }
    m_resolver.clear();
}

void StyleEngine::clearMasterResolver()
{
    if (Document* master = this->master())
        master->styleEngine()->clearResolver();
}

unsigned StyleEngine::resolverAccessCount() const
{
    return m_resolver ? m_resolver->accessCount() : 0;
}

void StyleEngine::didDetach()
{
    clearResolver();
}

bool StyleEngine::shouldClearResolver() const
{
    return !m_didCalculateResolver && !haveStylesheetsLoaded();
}

StyleResolverChange StyleEngine::resolverChanged(RecalcStyleTime time, StyleResolverUpdateMode mode)
{
    StyleResolverChange change;

    if (!isMaster()) {
        if (Document* master = this->master())
            master->styleResolverChanged(time, mode);
        return change;
    }

    // Don't bother updating, since we haven't loaded all our style info yet
    // and haven't calculated the style selector for the first time.
    if (!m_document.isActive() || shouldClearResolver()) {
        clearResolver();
        return change;
    }

    m_didCalculateResolver = true;
    if (m_document.didLayoutWithPendingStylesheets() && !hasPendingSheets())
        change.setNeedsRepaint();

    if (updateActiveStyleSheets(mode))
        change.setNeedsStyleRecalc();

    return change;
}

void StyleEngine::clearFontCache()
{
    // We should not recreate FontSelector. Instead, clear fontFaceCache.
    if (m_fontSelector)
        m_fontSelector->fontFaceCache()->clear();
    if (m_resolver)
        m_resolver->invalidateMatchedPropertiesCache();
}

void StyleEngine::updateGenericFontFamilySettings()
{
    if (!m_fontSelector)
        return;

    m_fontSelector->updateGenericFontFamilySettings(m_document);
    if (m_resolver)
        m_resolver->invalidateMatchedPropertiesCache();
}

void StyleEngine::removeFontFaceRules(const WillBeHeapVector<RawPtrWillBeMember<const StyleRuleFontFace> >& fontFaceRules)
{
    if (!m_fontSelector)
        return;

    FontFaceCache* cache = m_fontSelector->fontFaceCache();
    for (unsigned i = 0; i < fontFaceRules.size(); ++i)
        cache->remove(fontFaceRules[i]);
    if (m_resolver)
        m_resolver->invalidateMatchedPropertiesCache();
}

void StyleEngine::markTreeScopeDirty(TreeScope& scope)
{
    if (scope == m_document) {
        markDocumentDirty();
        return;
    }

    m_dirtyTreeScopes.add(&scope);
}

void StyleEngine::markDocumentDirty()
{
    m_documentScopeDirty = true;
    if (!HTMLImport::isMaster(&m_document))
        m_document.import()->master()->styleEngine()->markDocumentDirty();
}

static bool isCacheableForStyleElement(const StyleSheetContents& contents)
{
    // FIXME: Support copying import rules.
    if (!contents.importRules().isEmpty())
        return false;
    // Until import rules are supported in cached sheets it's not possible for loading to fail.
    ASSERT(!contents.didLoadErrorOccur());
    // It is not the original sheet anymore.
    if (contents.isMutable())
        return false;
    if (!contents.hasSyntacticallyValidCSSHeader())
        return false;
    return true;
}

PassRefPtrWillBeRawPtr<CSSStyleSheet> StyleEngine::createSheet(Element* e, const String& text, TextPosition startPosition, bool createdByParser)
{
    RefPtrWillBeRawPtr<CSSStyleSheet> styleSheet = nullptr;

    e->document().styleEngine()->addPendingSheet();

    if (!e->document().inQuirksMode()) {
        AtomicString textContent(text);

        WillBeHeapHashMap<AtomicString, RawPtrWillBeMember<StyleSheetContents> >::AddResult result = m_textToSheetCache.add(textContent, nullptr);
        if (result.isNewEntry || !result.storedValue->value) {
            styleSheet = StyleEngine::parseSheet(e, text, startPosition, createdByParser);
            if (result.isNewEntry && isCacheableForStyleElement(*styleSheet->contents())) {
                result.storedValue->value = styleSheet->contents();
                m_sheetToTextCache.add(styleSheet->contents(), textContent);
            }
        } else {
            StyleSheetContents* contents = result.storedValue->value;
            ASSERT(contents);
            ASSERT(isCacheableForStyleElement(*contents));
            ASSERT(contents->singleOwnerDocument() == e->document());
            styleSheet = CSSStyleSheet::createInline(contents, e, startPosition);
        }
    } else {
        // FIXME: currently we don't cache StyleSheetContents inQuirksMode.
        styleSheet = StyleEngine::parseSheet(e, text, startPosition, createdByParser);
    }

    ASSERT(styleSheet);
    styleSheet->setTitle(e->title());
    return styleSheet;
}

PassRefPtrWillBeRawPtr<CSSStyleSheet> StyleEngine::parseSheet(Element* e, const String& text, TextPosition startPosition, bool createdByParser)
{
    RefPtrWillBeRawPtr<CSSStyleSheet> styleSheet = nullptr;
    styleSheet = CSSStyleSheet::createInline(e, KURL(), startPosition, e->document().inputEncoding());
    styleSheet->contents()->parseStringAtPosition(text, startPosition, createdByParser);
    return styleSheet;
}

void StyleEngine::removeSheet(StyleSheetContents* contents)
{
    WillBeHeapHashMap<RawPtrWillBeMember<StyleSheetContents>, AtomicString>::iterator it = m_sheetToTextCache.find(contents);
    if (it == m_sheetToTextCache.end())
        return;

    m_textToSheetCache.remove(it->value);
    m_sheetToTextCache.remove(contents);
}

void StyleEngine::trace(Visitor* visitor)
{
    visitor->trace(m_injectedAuthorStyleSheets);
    visitor->trace(m_authorStyleSheets);
    visitor->trace(m_documentStyleSheetCollection);
    visitor->trace(m_styleSheetCollectionMap);
    visitor->trace(m_resolver);
    visitor->trace(m_textToSheetCache);
    visitor->trace(m_sheetToTextCache);
}

}
/* [<][>][^][v][top][bottom][index][help] */
root/Source/core/dom/StyleEngine.cpp

DEFINITIONS
