xref: /external/webkit/Source/WebCore/css/CSSStyleSelector.cpp

/*
 * Copyright (C) 1999 Lars Knoll (knoll (at) kde.org)
 *           (C) 2004-2005 Allan Sandfeld Jensen (kde (at) carewolf.com)
 * Copyright (C) 2006, 2007 Nicholas Shanks (webkit (at) nickshanks.com)
 * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
 * Copyright (C) 2007 Alexey Proskuryakov <ap (at) webkit.org>
 * Copyright (C) 2007, 2008 Eric Seidel <eric (at) webkit.org>
 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 * Copyright (c) 2011, Code Aurora Forum. 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 "CSSStyleSelector.h"

#include "Attribute.h"
#include "ContentData.h"
#include "CounterContent.h"
#include "CursorList.h"
#include "CSSBorderImageValue.h"
#include "CSSCursorImageValue.h"
#include "CSSFontFaceRule.h"
#include "CSSImportRule.h"
#include "CSSLineBoxContainValue.h"
#include "CSSMediaRule.h"
#include "CSSPageRule.h"
#include "CSSParser.h"
#include "CSSPrimitiveValueMappings.h"
#include "CSSPropertyNames.h"
#include "CSSReflectValue.h"
#include "CSSRuleList.h"
#include "CSSSelector.h"
#include "CSSSelectorList.h"
#include "CSSStyleApplyProperty.h"
#include "CSSStyleRule.h"
#include "CSSStyleSheet.h"
#include "CSSTimingFunctionValue.h"
#include "CSSValueList.h"
#include "CachedImage.h"
#include "Counter.h"
#include "FocusController.h"
#include "FontFamilyValue.h"
#include "FontValue.h"
#include "Frame.h"
#include "FrameView.h"
#include "HTMLDocument.h"
#include "HTMLElement.h"
#include "HTMLInputElement.h"
#include "HTMLNames.h"
#include "HTMLTextAreaElement.h"
#include "KeyframeList.h"
#include "LinkHash.h"
#include "Matrix3DTransformOperation.h"
#include "MatrixTransformOperation.h"
#include "MediaList.h"
#include "MediaQueryEvaluator.h"
#include "NodeRenderStyle.h"
#include "Page.h"
#include "PageGroup.h"
#include "Pair.h"
#include "PerspectiveTransformOperation.h"
#include "QuotesData.h"
#include "Rect.h"
#include "RenderScrollbar.h"
#include "RenderScrollbarTheme.h"
#include "RenderStyleConstants.h"
#include "RenderTheme.h"
#include "RotateTransformOperation.h"
#include "ScaleTransformOperation.h"
#include "SelectionController.h"
#include "Settings.h"
#include "ShadowData.h"
#include "ShadowValue.h"
#include "SkewTransformOperation.h"
#include "StyleCachedImage.h"
#include "StylePendingImage.h"
#include "StyleGeneratedImage.h"
#include "StyleSheetList.h"
#include "Text.h"
#include "TransformationMatrix.h"
#include "TranslateTransformOperation.h"
#include "UserAgentStyleSheets.h"
#include "WebKitCSSKeyframeRule.h"
#include "WebKitCSSKeyframesRule.h"
#include "WebKitCSSTransformValue.h"
#include "XMLNames.h"
#include <wtf/StdLibExtras.h>
#include <wtf/Vector.h>

#if USE(PLATFORM_STRATEGIES)
#include "PlatformStrategies.h"
#include "VisitedLinkStrategy.h"
#endif

#if ENABLE(DASHBOARD_SUPPORT)
#include "DashboardRegion.h"
#endif

#if ENABLE(SVG)
#include "XLinkNames.h"
#include "SVGNames.h"
#endif

#if ENABLE(WML)
#include "WMLNames.h"
#endif

#if PLATFORM(QT)
#include <qwebhistoryinterface.h>
#endif

using namespace std;

namespace WebCore {

using namespace HTMLNames;

#define HANDLE_INHERIT(prop, Prop) \
if (isInherit) { \
    m_style->set##Prop(m_parentStyle->prop()); \
    return; \
}

#define HANDLE_INHERIT_AND_INITIAL(prop, Prop) \
HANDLE_INHERIT(prop, Prop) \
if (isInitial) { \
    m_style->set##Prop(RenderStyle::initial##Prop()); \
    return; \
}

#define HANDLE_INHERIT_AND_INITIAL_WITH_VALUE(prop, Prop, Value) \
HANDLE_INHERIT(prop, Prop) \
if (isInitial) { \
    m_style->set##Prop(RenderStyle::initial##Value());\
    return;\
}

#define HANDLE_INHERIT_AND_INITIAL_AND_PRIMITIVE(prop, Prop) \
HANDLE_INHERIT_AND_INITIAL(prop, Prop) \
if (primitiveValue) \
    m_style->set##Prop(*primitiveValue);

#define HANDLE_INHERIT_AND_INITIAL_AND_PRIMITIVE_WITH_VALUE(prop, Prop, Value) \
HANDLE_INHERIT_AND_INITIAL_WITH_VALUE(prop, Prop, Value) \
if (primitiveValue) \
    m_style->set##Prop(*primitiveValue);

#define HANDLE_ANIMATION_INHERIT_AND_INITIAL(prop, Prop) \
if (isInherit) { \
    AnimationList* list = m_style->accessAnimations(); \
    const AnimationList* parentList = m_parentStyle->animations(); \
    size_t i = 0, parentSize = parentList ? parentList->size() : 0; \
    for ( ; i < parentSize && parentList->animation(i)->is##Prop##Set(); ++i) { \
        if (list->size() <= i) \
            list->append(Animation::create()); \
        list->animation(i)->set##Prop(parentList->animation(i)->prop()); \
    } \
    \
    /* Reset any remaining animations to not have the property set. */ \
    for ( ; i < list->size(); ++i) \
        list->animation(i)->clear##Prop(); \
} else if (isInitial) { \
    AnimationList* list = m_style->accessAnimations(); \
    if (list->isEmpty()) \
        list->append(Animation::create()); \
    list->animation(0)->set##Prop(Animation::initialAnimation##Prop()); \
    for (size_t i = 1; i < list->size(); ++i) \
        list->animation(0)->clear##Prop(); \
}

#define HANDLE_ANIMATION_VALUE(prop, Prop, value) { \
HANDLE_ANIMATION_INHERIT_AND_INITIAL(prop, Prop) \
if (isInherit || isInitial) \
    return; \
AnimationList* list = m_style->accessAnimations(); \
size_t childIndex = 0; \
if (value->isValueList()) { \
    /* Walk each value and put it into an animation, creating new animations as needed. */ \
    CSSValueList* valueList = static_cast<CSSValueList*>(value); \
    for (unsigned int i = 0; i < valueList->length(); i++) { \
        if (childIndex <= list->size()) \
            list->append(Animation::create()); \
        mapAnimation##Prop(list->animation(childIndex), valueList->itemWithoutBoundsCheck(i)); \
        ++childIndex; \
    } \
} else { \
    if (list->isEmpty()) \
        list->append(Animation::create()); \
    mapAnimation##Prop(list->animation(childIndex), value); \
    childIndex = 1; \
} \
for ( ; childIndex < list->size(); ++childIndex) { \
    /* Reset all remaining animations to not have the property set. */ \
    list->animation(childIndex)->clear##Prop(); \
} \
}

#define HANDLE_TRANSITION_INHERIT_AND_INITIAL(prop, Prop) \
if (isInherit) { \
    AnimationList* list = m_style->accessTransitions(); \
    const AnimationList* parentList = m_parentStyle->transitions(); \
    size_t i = 0, parentSize = parentList ? parentList->size() : 0; \
    for ( ; i < parentSize && parentList->animation(i)->is##Prop##Set(); ++i) { \
        if (list->size() <= i) \
            list->append(Animation::create()); \
        list->animation(i)->set##Prop(parentList->animation(i)->prop()); \
    } \
    \
    /* Reset any remaining transitions to not have the property set. */ \
    for ( ; i < list->size(); ++i) \
        list->animation(i)->clear##Prop(); \
} else if (isInitial) { \
    AnimationList* list = m_style->accessTransitions(); \
    if (list->isEmpty()) \
        list->append(Animation::create()); \
    list->animation(0)->set##Prop(Animation::initialAnimation##Prop()); \
    for (size_t i = 1; i < list->size(); ++i) \
        list->animation(0)->clear##Prop(); \
}

#define HANDLE_TRANSITION_VALUE(prop, Prop, value) { \
HANDLE_TRANSITION_INHERIT_AND_INITIAL(prop, Prop) \
if (isInherit || isInitial) \
    return; \
AnimationList* list = m_style->accessTransitions(); \
size_t childIndex = 0; \
if (value->isValueList()) { \
    /* Walk each value and put it into a transition, creating new animations as needed. */ \
    CSSValueList* valueList = static_cast<CSSValueList*>(value); \
    for (unsigned int i = 0; i < valueList->length(); i++) { \
        if (childIndex <= list->size()) \
            list->append(Animation::create()); \
        mapAnimation##Prop(list->animation(childIndex), valueList->itemWithoutBoundsCheck(i)); \
        ++childIndex; \
    } \
} else { \
    if (list->isEmpty()) \
        list->append(Animation::create()); \
    mapAnimation##Prop(list->animation(childIndex), value); \
    childIndex = 1; \
} \
for ( ; childIndex < list->size(); ++childIndex) { \
    /* Reset all remaining transitions to not have the property set. */ \
    list->animation(childIndex)->clear##Prop(); \
} \
}

#define HANDLE_INHERIT_COND(propID, prop, Prop) \
if (id == propID) { \
    m_style->set##Prop(m_parentStyle->prop()); \
    return; \
}

#define HANDLE_INHERIT_COND_WITH_BACKUP(propID, prop, propAlt, Prop) \
if (id == propID) { \
    if (m_parentStyle->prop().isValid()) \
        m_style->set##Prop(m_parentStyle->prop()); \
    else \
        m_style->set##Prop(m_parentStyle->propAlt()); \
    return; \
}

#define HANDLE_INITIAL_COND(propID, Prop) \
if (id == propID) { \
    m_style->set##Prop(RenderStyle::initial##Prop()); \
    return; \
}

#define HANDLE_INITIAL_COND_WITH_VALUE(propID, Prop, Value) \
if (id == propID) { \
    m_style->set##Prop(RenderStyle::initial##Value()); \
    return; \
}

class RuleData {
public:
    RuleData(CSSStyleRule*, CSSSelector*, unsigned position);

    unsigned position() const { return m_position; }
    CSSStyleRule* rule() const { return m_rule; }
    CSSSelector* selector() const { return m_selector; }

    bool hasFastCheckableSelector() const { return m_hasFastCheckableSelector; }
    bool hasMultipartSelector() const { return m_hasMultipartSelector; }
    bool hasTopSelectorMatchingHTMLBasedOnRuleHash() const { return m_hasTopSelectorMatchingHTMLBasedOnRuleHash; }
    unsigned specificity() const { return m_specificity; }

    // Try to balance between memory usage (there can be lots of RuleData objects) and good filtering performance.
    static const unsigned maximumIdentifierCount = 4;
    const unsigned* descendantSelectorIdentifierHashes() const { return m_descendantSelectorIdentifierHashes; }

private:
    void collectDescendantSelectorIdentifierHashes();
    void collectIdentifierHashes(const CSSSelector*, unsigned& identifierCount);

    CSSStyleRule* m_rule;
    CSSSelector* m_selector;
    unsigned m_specificity;
    unsigned m_position : 29;
    bool m_hasFastCheckableSelector : 1;
    bool m_hasMultipartSelector : 1;
    bool m_hasTopSelectorMatchingHTMLBasedOnRuleHash : 1;
    // Use plain array instead of a Vector to minimize memory overhead.
    unsigned m_descendantSelectorIdentifierHashes[maximumIdentifierCount];
};

class RuleSet {
    WTF_MAKE_NONCOPYABLE(RuleSet);
public:
    RuleSet();
    ~RuleSet();

    typedef HashMap<AtomicStringImpl*, Vector<RuleData>*> AtomRuleMap;

    void addRulesFromSheet(CSSStyleSheet*, const MediaQueryEvaluator&, CSSStyleSelector* = 0);

    void addStyleRule(CSSStyleRule* item);
    void addRule(CSSStyleRule* rule, CSSSelector* sel);
    void addPageRule(CSSStyleRule* rule, CSSSelector* sel);
    void addToRuleSet(AtomicStringImpl* key, AtomRuleMap& map,
                      CSSStyleRule* rule, CSSSelector* sel);
    void shrinkToFit();
    void disableAutoShrinkToFit() { m_autoShrinkToFitEnabled = false; }

    void collectFeatures(CSSStyleSelector::Features&) const;

    const Vector<RuleData>* getIDRules(AtomicStringImpl* key) const { return m_idRules.get(key); }
    const Vector<RuleData>* getClassRules(AtomicStringImpl* key) const { return m_classRules.get(key); }
    const Vector<RuleData>* getTagRules(AtomicStringImpl* key) const { return m_tagRules.get(key); }
    const Vector<RuleData>* getPseudoRules(AtomicStringImpl* key) const { return m_pseudoRules.get(key); }
    const Vector<RuleData>* getUniversalRules() const { return &m_universalRules; }
    const Vector<RuleData>* getPageRules() const { return &m_pageRules; }

public:
    AtomRuleMap m_idRules;
    AtomRuleMap m_classRules;
    AtomRuleMap m_tagRules;
    AtomRuleMap m_pseudoRules;
    Vector<RuleData> m_universalRules;
    Vector<RuleData> m_pageRules;
    unsigned m_ruleCount;
    bool m_autoShrinkToFitEnabled;
};

static RuleSet* defaultStyle;
static RuleSet* defaultQuirksStyle;
static RuleSet* defaultPrintStyle;
static RuleSet* defaultViewSourceStyle;
static CSSStyleSheet* simpleDefaultStyleSheet;

static RuleSet* siblingRulesInDefaultStyle;

RenderStyle* CSSStyleSelector::s_styleNotYetAvailable;

static void loadFullDefaultStyle();
static void loadSimpleDefaultStyle();
// FIXME: It would be nice to use some mechanism that guarantees this is in sync with the real UA stylesheet.
static const char* simpleUserAgentStyleSheet = "html,body,div{display:block}head{display:none}body{margin:8px}div:focus,span:focus{outline:auto 5px -webkit-focus-ring-color}a:-webkit-any-link{color:-webkit-link;text-decoration:underline}a:-webkit-any-link:active{color:-webkit-activelink}";

static inline bool elementCanUseSimpleDefaultStyle(Element* e)
{
    return e->hasTagName(htmlTag) || e->hasTagName(headTag) || e->hasTagName(bodyTag) || e->hasTagName(divTag) || e->hasTagName(spanTag) || e->hasTagName(brTag) || e->hasTagName(aTag);
}

static inline void collectSiblingRulesInDefaultStyle()
{
    CSSStyleSelector::Features features;
    defaultStyle->collectFeatures(features);
    ASSERT(features.idsInRules.isEmpty());
    delete siblingRulesInDefaultStyle;
    siblingRulesInDefaultStyle = features.siblingRules.leakPtr();
}

static inline void assertNoSiblingRulesInDefaultStyle()
{
#ifndef NDEBUG
    if (siblingRulesInDefaultStyle)
        return;
    collectSiblingRulesInDefaultStyle();
    ASSERT(!siblingRulesInDefaultStyle);
#endif
}

static const MediaQueryEvaluator& screenEval()
{
    DEFINE_STATIC_LOCAL(const MediaQueryEvaluator, staticScreenEval, ("screen"));
    return staticScreenEval;
}

static const MediaQueryEvaluator& printEval()
{
    DEFINE_STATIC_LOCAL(const MediaQueryEvaluator, staticPrintEval, ("print"));
    return staticPrintEval;
}

static CSSMutableStyleDeclaration* leftToRightDeclaration()
{
    DEFINE_STATIC_LOCAL(RefPtr<CSSMutableStyleDeclaration>, leftToRightDecl, (CSSMutableStyleDeclaration::create()));
    if (!leftToRightDecl->length()) {
        leftToRightDecl->setProperty(CSSPropertyDirection, "ltr", false, false);
        leftToRightDecl->setStrictParsing(false);
    }
    return leftToRightDecl.get();
}

static CSSMutableStyleDeclaration* rightToLeftDeclaration()
{
    DEFINE_STATIC_LOCAL(RefPtr<CSSMutableStyleDeclaration>, rightToLeftDecl, (CSSMutableStyleDeclaration::create()));
    if (!rightToLeftDecl->length()) {
        rightToLeftDecl->setProperty(CSSPropertyDirection, "rtl", false, false);
        rightToLeftDecl->setStrictParsing(false);
    }
    return rightToLeftDecl.get();
}

CSSStyleSelector::CSSStyleSelector(Document* document, StyleSheetList* styleSheets, CSSStyleSheet* mappedElementSheet,
                                   CSSStyleSheet* pageUserSheet, const Vector<RefPtr<CSSStyleSheet> >* pageGroupUserSheets,
                                   bool strictParsing, bool matchAuthorAndUserStyles)
    : m_backgroundData(BackgroundFillLayer)
    , m_checker(document, strictParsing)
    , m_element(0)
    , m_styledElement(0)
    , m_elementLinkState(NotInsideLink)
    , m_fontSelector(CSSFontSelector::create(document))
    , m_applyProperty(CSSStyleApplyProperty::sharedCSSStyleApplyProperty())
{
    m_matchAuthorAndUserStyles = matchAuthorAndUserStyles;

    Element* root = document->documentElement();

    if (!defaultStyle) {
        if (!root || elementCanUseSimpleDefaultStyle(root))
            loadSimpleDefaultStyle();
        else {
            loadFullDefaultStyle();
        }
    }

    // construct document root element default style. this is needed
    // to evaluate media queries that contain relative constraints, like "screen and (max-width: 10em)"
    // This is here instead of constructor, because when constructor is run,
    // document doesn't have documentElement
    // NOTE: this assumes that element that gets passed to styleForElement -call
    // is always from the document that owns the style selector
    FrameView* view = document->view();
    if (view)
        m_medium = adoptPtr(new MediaQueryEvaluator(view->mediaType()));
    else
        m_medium = adoptPtr(new MediaQueryEvaluator("all"));

    if (root)
        m_rootDefaultStyle = styleForElement(root, 0, false, true); // don't ref, because the RenderStyle is allocated from global heap

    if (m_rootDefaultStyle && view)
        m_medium = adoptPtr(new MediaQueryEvaluator(view->mediaType(), view->frame(), m_rootDefaultStyle.get()));

    m_authorStyle = adoptPtr(new RuleSet);
    // Adding rules from multiple sheets, shrink at the end.
    m_authorStyle->disableAutoShrinkToFit();

    // FIXME: This sucks! The user sheet is reparsed every time!
    OwnPtr<RuleSet> tempUserStyle = adoptPtr(new RuleSet);
    if (pageUserSheet)
        tempUserStyle->addRulesFromSheet(pageUserSheet, *m_medium, this);
    if (pageGroupUserSheets) {
        unsigned length = pageGroupUserSheets->size();
        for (unsigned i = 0; i < length; i++) {
            if (pageGroupUserSheets->at(i)->isUserStyleSheet())
                tempUserStyle->addRulesFromSheet(pageGroupUserSheets->at(i).get(), *m_medium, this);
            else
                m_authorStyle->addRulesFromSheet(pageGroupUserSheets->at(i).get(), *m_medium, this);
        }
    }

    if (tempUserStyle->m_ruleCount > 0 || tempUserStyle->m_pageRules.size() > 0)
        m_userStyle = tempUserStyle.release();

    // Add rules from elements like SVG's <font-face>
    if (mappedElementSheet)
        m_authorStyle->addRulesFromSheet(mappedElementSheet, *m_medium, this);

    // add stylesheets from document
    unsigned length = styleSheets->length();
    for (unsigned i = 0; i < length; i++) {
        StyleSheet* sheet = styleSheets->item(i);
        if (sheet->isCSSStyleSheet() && !sheet->disabled())
            m_authorStyle->addRulesFromSheet(static_cast<CSSStyleSheet*>(sheet), *m_medium, this);
    }
    // Collect all ids and rules using sibling selectors (:first-child and similar)
    // in the current set of stylesheets. Style sharing code uses this information to reject
    // sharing candidates.
    // Usually there are no sibling rules in the default style but the MathML sheet has some.
    if (siblingRulesInDefaultStyle)
        siblingRulesInDefaultStyle->collectFeatures(m_features);
    m_authorStyle->collectFeatures(m_features);
    if (m_userStyle)
        m_userStyle->collectFeatures(m_features);

    m_authorStyle->shrinkToFit();
    if (m_features.siblingRules)
        m_features.siblingRules->shrinkToFit();

    if (document->renderer() && document->renderer()->style())
        document->renderer()->style()->font().update(fontSelector());
}

// This is a simplified style setting function for keyframe styles
void CSSStyleSelector::addKeyframeStyle(PassRefPtr<WebKitCSSKeyframesRule> rule)
{
    AtomicString s(rule->name());
    m_keyframesRuleMap.add(s.impl(), rule);
}

CSSStyleSelector::~CSSStyleSelector()
{
    m_fontSelector->clearDocument();
    deleteAllValues(m_viewportDependentMediaQueryResults);
}

CSSStyleSelector::Features::Features()
    : usesFirstLineRules(false)
    , usesBeforeAfterRules(false)
    , usesLinkRules(false)
{
}

CSSStyleSelector::Features::~Features()
{
}

static CSSStyleSheet* parseUASheet(const String& str)
{
    CSSStyleSheet* sheet = CSSStyleSheet::create().releaseRef(); // leak the sheet on purpose
    sheet->parseString(str);
    return sheet;
}

static CSSStyleSheet* parseUASheet(const char* characters, unsigned size)
{
    return parseUASheet(String(characters, size));
}

static void loadFullDefaultStyle()
{
    if (simpleDefaultStyleSheet) {
        ASSERT(defaultStyle);
        delete defaultStyle;
        simpleDefaultStyleSheet->deref();
        defaultStyle = new RuleSet;
        simpleDefaultStyleSheet = 0;
    } else {
        ASSERT(!defaultStyle);
        defaultStyle = new RuleSet;
        defaultPrintStyle = new RuleSet;
        defaultQuirksStyle = new RuleSet;
    }

    // Strict-mode rules.
    String defaultRules = String(htmlUserAgentStyleSheet, sizeof(htmlUserAgentStyleSheet)) + RenderTheme::defaultTheme()->extraDefaultStyleSheet();
    CSSStyleSheet* defaultSheet = parseUASheet(defaultRules);
    defaultStyle->addRulesFromSheet(defaultSheet, screenEval());
    defaultPrintStyle->addRulesFromSheet(defaultSheet, printEval());

    // Quirks-mode rules.
    String quirksRules = String(quirksUserAgentStyleSheet, sizeof(quirksUserAgentStyleSheet)) + RenderTheme::defaultTheme()->extraQuirksStyleSheet();
    CSSStyleSheet* quirksSheet = parseUASheet(quirksRules);
    defaultQuirksStyle->addRulesFromSheet(quirksSheet, screenEval());
}

static void loadSimpleDefaultStyle()
{
    ASSERT(!defaultStyle);
    ASSERT(!simpleDefaultStyleSheet);

    defaultStyle = new RuleSet;
    defaultPrintStyle = new RuleSet;
    defaultQuirksStyle = new RuleSet;

    simpleDefaultStyleSheet = parseUASheet(simpleUserAgentStyleSheet, strlen(simpleUserAgentStyleSheet));
    defaultStyle->addRulesFromSheet(simpleDefaultStyleSheet, screenEval());

    // No need to initialize quirks sheet yet as there are no quirk rules for elements allowed in simple default style.
}

static void loadViewSourceStyle()
{
    ASSERT(!defaultViewSourceStyle);
    defaultViewSourceStyle = new RuleSet;
    defaultViewSourceStyle->addRulesFromSheet(parseUASheet(sourceUserAgentStyleSheet, sizeof(sourceUserAgentStyleSheet)), screenEval());
}

static inline void collectElementIdentifierHashes(const Element* element, Vector<unsigned, 4>& identifierHashes)
{
    identifierHashes.append(element->localName().impl()->existingHash());
    if (element->hasID())
        identifierHashes.append(element->idForStyleResolution().impl()->existingHash());
    const StyledElement* styledElement = element->isStyledElement() ? static_cast<const StyledElement*>(element) : 0;
    if (styledElement && styledElement->hasClass()) {
        const SpaceSplitString& classNames = styledElement->classNames();
        size_t count = classNames.size();
        for (size_t i = 0; i < count; ++i)
            identifierHashes.append(classNames[i].impl()->existingHash());
    }
}

void CSSStyleSelector::pushParentStackFrame(Element* parent)
{
    ASSERT(m_ancestorIdentifierFilter);
    ASSERT(m_parentStack.isEmpty() || m_parentStack.last().element == parent->parentElement());
    ASSERT(!m_parentStack.isEmpty() || !parent->parentElement());
    m_parentStack.append(ParentStackFrame(parent));
    ParentStackFrame& parentFrame = m_parentStack.last();
    // Mix tags, class names and ids into some sort of weird bouillabaisse.
    // The filter is used for fast rejection of child and descendant selectors.
    collectElementIdentifierHashes(parent, parentFrame.identifierHashes);
    size_t count = parentFrame.identifierHashes.size();
    for (size_t i = 0; i < count; ++i)
        m_ancestorIdentifierFilter->add(parentFrame.identifierHashes[i]);
}

void CSSStyleSelector::popParentStackFrame()
{
    ASSERT(!m_parentStack.isEmpty());
    ASSERT(m_ancestorIdentifierFilter);
    const ParentStackFrame& parentFrame = m_parentStack.last();
    size_t count = parentFrame.identifierHashes.size();
    for (size_t i = 0; i < count; ++i)
        m_ancestorIdentifierFilter->remove(parentFrame.identifierHashes[i]);
    m_parentStack.removeLast();
    if (m_parentStack.isEmpty()) {
        ASSERT(m_ancestorIdentifierFilter->likelyEmpty());
        m_ancestorIdentifierFilter.clear();
    }
}

void CSSStyleSelector::pushParent(Element* parent)
{
    if (m_parentStack.isEmpty()) {
        ASSERT(!m_ancestorIdentifierFilter);
        m_ancestorIdentifierFilter = adoptPtr(new BloomFilter<bloomFilterKeyBits>);
        // If the element is not the root itself, build the stack starting from the root.
        if (parent->parentElement()) {
            Vector<Element*, 30> ancestors;
            for (Element* ancestor = parent; ancestor; ancestor = ancestor->parentElement())
                ancestors.append(ancestor);
            int count = ancestors.size();
            for (int n = count - 1; n >= 0; --n)
                pushParentStackFrame(ancestors[n]);
            return;
        }
    } else if (!parent->parentElement()) {
        // We are not always invoked consistently. For example, script execution can cause us to enter
        // style recalc in the middle of tree building. Reset the stack if we see a new root element.
        ASSERT(m_ancestorIdentifierFilter);
        m_ancestorIdentifierFilter->clear();
        m_parentStack.resize(0);
    } else {
        ASSERT(m_ancestorIdentifierFilter);
        // We may get invoked for some random elements in some wacky cases during style resolve.
        // Pause maintaining the stack in this case.
        if (m_parentStack.last().element != parent->parentElement())
            return;
    }
    pushParentStackFrame(parent);
}

void CSSStyleSelector::popParent(Element* parent)
{
    if (m_parentStack.isEmpty() || m_parentStack.last().element != parent)
        return;
    popParentStackFrame();
}

void CSSStyleSelector::addMatchedDeclaration(CSSMutableStyleDeclaration* decl)
{
    m_matchedDecls.append(decl);
}

void CSSStyleSelector::matchRules(RuleSet* rules, int& firstRuleIndex, int& lastRuleIndex, bool includeEmptyRules)
{
    m_matchedRules.clear();

    if (!rules || !m_element)
        return;

    // We need to collect the rules for id, class, tag, and everything else into a buffer and
    // then sort the buffer.
    if (m_element->hasID())
        matchRulesForList(rules->getIDRules(m_element->idForStyleResolution().impl()), firstRuleIndex, lastRuleIndex, includeEmptyRules);
    if (m_element->hasClass()) {
        ASSERT(m_styledElement);
        const SpaceSplitString& classNames = m_styledElement->classNames();
        size_t size = classNames.size();
        for (size_t i = 0; i < size; ++i)
            matchRulesForList(rules->getClassRules(classNames[i].impl()), firstRuleIndex, lastRuleIndex, includeEmptyRules);
    }
    if (!m_element->shadowPseudoId().isEmpty()) {
        ASSERT(m_styledElement);
        matchRulesForList(rules->getPseudoRules(m_element->shadowPseudoId().impl()), firstRuleIndex, lastRuleIndex, includeEmptyRules);
    }
    matchRulesForList(rules->getTagRules(m_element->localName().impl()), firstRuleIndex, lastRuleIndex, includeEmptyRules);
    matchRulesForList(rules->getUniversalRules(), firstRuleIndex, lastRuleIndex, includeEmptyRules);

    // If we didn't match any rules, we're done.
    if (m_matchedRules.isEmpty())
        return;

    // Sort the set of matched rules.
    sortMatchedRules();

    // Now transfer the set of matched rules over to our list of decls.
    if (!m_checker.m_collectRulesOnly) {
        for (unsigned i = 0; i < m_matchedRules.size(); i++)
            addMatchedDeclaration(m_matchedRules[i]->rule()->declaration());
    } else {
        for (unsigned i = 0; i < m_matchedRules.size(); i++) {
            if (!m_ruleList)
                m_ruleList = CSSRuleList::create();
            m_ruleList->append(m_matchedRules[i]->rule());
        }
    }
}

inline bool CSSStyleSelector::fastRejectSelector(const RuleData& ruleData) const
{
    ASSERT(m_ancestorIdentifierFilter);
    const unsigned* descendantSelectorIdentifierHashes = ruleData.descendantSelectorIdentifierHashes();
    for (unsigned n = 0; n < RuleData::maximumIdentifierCount && descendantSelectorIdentifierHashes[n]; ++n) {
        if (!m_ancestorIdentifierFilter->mayContain(descendantSelectorIdentifierHashes[n]))
            return true;
    }
    return false;
}

void CSSStyleSelector::matchRulesForList(const Vector<RuleData>* rules, int& firstRuleIndex, int& lastRuleIndex, bool includeEmptyRules)
{
    if (!rules)
        return;
    // In some cases we may end up looking up style for random elements in the middle of a recursive tree resolve.
    // Ancestor identifier filter won't be up-to-date in that case and we can't use the fast path.
    bool canUseFastReject = !m_parentStack.isEmpty() && m_parentStack.last().element == m_parentNode;

    unsigned size = rules->size();
    for (unsigned i = 0; i < size; ++i) {
        const RuleData& ruleData = rules->at(i);
        if (canUseFastReject && fastRejectSelector(ruleData))
            continue;
        if (checkSelector(ruleData)) {
            // If the rule has no properties to apply, then ignore it in the non-debug mode.
            CSSStyleRule* rule = ruleData.rule();
            CSSMutableStyleDeclaration* decl = rule->declaration();
            if (!decl || (!decl->length() && !includeEmptyRules))
                continue;
            if (m_checker.m_sameOriginOnly && !m_checker.m_document->securityOrigin()->canRequest(rule->baseURL()))
                continue;
            // If we're matching normal rules, set a pseudo bit if
            // we really just matched a pseudo-element.
            if (m_dynamicPseudo != NOPSEUDO && m_checker.m_pseudoStyle == NOPSEUDO) {
                if (m_checker.m_collectRulesOnly)
                    continue;
                if (m_dynamicPseudo < FIRST_INTERNAL_PSEUDOID)
                    m_style->setHasPseudoStyle(m_dynamicPseudo);
            } else {
                // Update our first/last rule indices in the matched rules array.
                lastRuleIndex = m_matchedDecls.size() + m_matchedRules.size();
                if (firstRuleIndex == -1)
                    firstRuleIndex = lastRuleIndex;

                // Add this rule to our list of matched rules.
                addMatchedRule(&ruleData);
            }
        }
    }
}

static inline bool compareRules(const RuleData* r1, const RuleData* r2)
{
    unsigned specificity1 = r1->specificity();
    unsigned specificity2 = r2->specificity();
    return (specificity1 == specificity2) ? r1->position() < r2->position() : specificity1 < specificity2;
}

void CSSStyleSelector::sortMatchedRules()
{
    std::sort(m_matchedRules.begin(), m_matchedRules.end(), compareRules);
}

inline EInsideLink CSSStyleSelector::SelectorChecker::determineLinkState(Element* element) const
{
    if (!element || !element->isLink())
        return NotInsideLink;
    return determineLinkStateSlowCase(element);
}

inline void CSSStyleSelector::initElement(Element* e)
{
    if (m_element != e) {
        m_element = e;
        m_styledElement = m_element && m_element->isStyledElement() ? static_cast<StyledElement*>(m_element) : 0;
        m_elementLinkState = m_checker.determineLinkState(m_element);
        if (e && e == e->document()->documentElement()) {
            e->document()->setDirectionSetOnDocumentElement(false);
            e->document()->setWritingModeSetOnDocumentElement(false);
        }
    }
}

inline void CSSStyleSelector::initForStyleResolve(Element* e, RenderStyle* parentStyle, PseudoId pseudoID)
{
    m_checker.m_pseudoStyle = pseudoID;

    m_parentNode = e ? e->parentNodeForRenderingAndStyle() : 0;

    if (parentStyle)
        m_parentStyle = parentStyle;
    else
        m_parentStyle = m_parentNode ? m_parentNode->renderStyle() : 0;

    Node* docElement = e ? e->document()->documentElement() : 0;
    RenderStyle* docStyle = m_checker.m_document->renderStyle();
    m_rootElementStyle = docElement && e != docElement ? docElement->renderStyle() : docStyle;

    m_style = 0;

    m_matchedDecls.clear();

    m_pendingImageProperties.clear();

    m_ruleList = 0;

    m_fontDirty = false;
}

static inline const AtomicString* linkAttribute(Node* node)
{
    if (!node->isLink())
        return 0;

    ASSERT(node->isElementNode());
    Element* element = static_cast<Element*>(node);
    if (element->isHTMLElement())
        return &element->fastGetAttribute(hrefAttr);

#if ENABLE(WML)
    if (element->isWMLElement()) {
        // <anchor> elements don't have href attributes, but we still want to
        // appear as link, so linkAttribute() has to return a non-null value!
        if (element->hasTagName(WMLNames::anchorTag))
            return &emptyAtom;

        return &element->fastGetAttribute(hrefAttr);
    }
#endif

#if ENABLE(SVG)
    if (element->isSVGElement())
        return &element->fastGetAttribute(XLinkNames::hrefAttr);
#endif

    return 0;
}

CSSStyleSelector::SelectorChecker::SelectorChecker(Document* document, bool strictParsing)
    : m_document(document)
    , m_strictParsing(strictParsing)
    , m_collectRulesOnly(false)
    , m_sameOriginOnly(false)
    , m_pseudoStyle(NOPSEUDO)
    , m_documentIsHTML(document->isHTMLDocument())
    , m_matchVisitedPseudoClass(false)
{
}

EInsideLink CSSStyleSelector::SelectorChecker::determineLinkStateSlowCase(Element* element) const
{
    ASSERT(element->isLink());

    const AtomicString* attr = linkAttribute(element);
    if (!attr || attr->isNull())
        return NotInsideLink;

#if PLATFORM(QT)
    Vector<UChar, 512> url;
    visitedURL(m_document->baseURL(), *attr, url);
    if (url.isEmpty())
        return InsideUnvisitedLink;

    // If the Qt4.4 interface for the history is used, we will have to fallback
    // to the old global history.
    QWebHistoryInterface* iface = QWebHistoryInterface::defaultInterface();
    if (iface)
        return iface->historyContains(QString(reinterpret_cast<QChar*>(url.data()), url.size())) ? InsideVisitedLink : InsideUnvisitedLink;

    LinkHash hash = visitedLinkHash(url.data(), url.size());
    if (!hash)
        return InsideUnvisitedLink;
#else
    LinkHash hash = visitedLinkHash(m_document->baseURL(), *attr);
    if (!hash)
        return InsideUnvisitedLink;
#endif

    Frame* frame = m_document->frame();
    if (!frame)
        return InsideUnvisitedLink;

    Page* page = frame->page();
    if (!page)
        return InsideUnvisitedLink;

    m_linksCheckedForVisitedState.add(hash);

#if USE(PLATFORM_STRATEGIES)
    return platformStrategies()->visitedLinkStrategy()->isLinkVisited(page, hash) ? InsideVisitedLink : InsideUnvisitedLink;
#else
    return page->group().isLinkVisited(hash) ? InsideVisitedLink : InsideUnvisitedLink;
#endif
}

bool CSSStyleSelector::SelectorChecker::checkSelector(CSSSelector* sel, Element* element) const
{
    PseudoId dynamicPseudo = NOPSEUDO;
    return checkSelector(sel, element, 0, dynamicPseudo, false, false) == SelectorMatches;
}

static const unsigned cStyleSearchThreshold = 10;
static const unsigned cStyleSearchLevelThreshold = 10;

Node* CSSStyleSelector::locateCousinList(Element* parent, unsigned& visitedNodeCount) const
{
    if (visitedNodeCount >= cStyleSearchThreshold * cStyleSearchLevelThreshold)
        return 0;
    if (!parent || !parent->isStyledElement())
        return 0;
    StyledElement* p = static_cast<StyledElement*>(parent);
    if (p->inlineStyleDecl())
        return 0;
    if (p->hasID() && m_features.idsInRules.contains(p->idForStyleResolution().impl()))
        return 0;

    RenderStyle* parentStyle = p->renderStyle();
    unsigned subcount = 0;
    Node* thisCousin = p;
    Node* currentNode = p->previousSibling();

    // Reserve the tries for this level. This effectively makes sure that the algorithm
    // will never go deeper than cStyleSearchLevelThreshold levels into recursion.
    visitedNodeCount += cStyleSearchThreshold;
    while (thisCousin) {
        while (currentNode) {
            ++subcount;
            if (currentNode->renderStyle() == parentStyle && currentNode->lastChild()) {
                // Adjust for unused reserved tries.
                visitedNodeCount -= cStyleSearchThreshold - subcount;
                return currentNode->lastChild();
            }
            if (subcount >= cStyleSearchThreshold)
                return 0;
            currentNode = currentNode->previousSibling();
        }
        currentNode = locateCousinList(thisCousin->parentElement(), visitedNodeCount);
        thisCousin = currentNode;
    }

    return 0;
}

bool CSSStyleSelector::matchesSiblingRules()
{
    int firstSiblingRule = -1, lastSiblingRule = -1;
    matchRules(m_features.siblingRules.get(), firstSiblingRule, lastSiblingRule, false);
    if (m_matchedDecls.isEmpty())
        return false;
    m_matchedDecls.clear();
    return true;
}

bool CSSStyleSelector::canShareStyleWithElement(Node* node) const
{
    if (!node->isStyledElement())
        return false;

    StyledElement* element = static_cast<StyledElement*>(node);
    RenderStyle* style = element->renderStyle();

    if (!style)
        return false;
    if (style->unique())
        return false;
    if (element->tagQName() != m_element->tagQName())
        return false;
    if (element->hasClass() != m_element->hasClass())
        return false;
    if (element->inlineStyleDecl())
        return false;
    if (element->hasMappedAttributes() != m_styledElement->hasMappedAttributes())
        return false;
    if (element->isLink() != m_element->isLink())
        return false;
    if (style->affectedByAttributeSelectors())
        return false;
    if (element->hovered() != m_element->hovered())
        return false;
    if (element->active() != m_element->active())
        return false;
    if (element->focused() != m_element->focused())
        return false;
    if (element->shadowPseudoId() != m_element->shadowPseudoId())
        return false;
    if (element == element->document()->cssTarget())
        return false;
    if (m_element == m_element->document()->cssTarget())
        return false;
    if (element->fastGetAttribute(typeAttr) != m_element->fastGetAttribute(typeAttr))
        return false;
    if (element->fastGetAttribute(XMLNames::langAttr) != m_element->fastGetAttribute(XMLNames::langAttr))
        return false;
    if (element->fastGetAttribute(langAttr) != m_element->fastGetAttribute(langAttr))
        return false;
    if (element->fastGetAttribute(readonlyAttr) != m_element->fastGetAttribute(readonlyAttr))
        return false;
    if (element->fastGetAttribute(cellpaddingAttr) != m_element->fastGetAttribute(cellpaddingAttr))
        return false;

    if (element->hasID() && m_features.idsInRules.contains(element->idForStyleResolution().impl()))
        return false;

    bool isControl = element->isFormControlElement();

    if (isControl != m_element->isFormControlElement())
        return false;

    if (isControl) {
        InputElement* thisInputElement = element->toInputElement();
        InputElement* otherInputElement = m_element->toInputElement();

        if (!thisInputElement || !otherInputElement)
            return false;

        if (thisInputElement->isAutofilled() != otherInputElement->isAutofilled())
            return false;
        if (thisInputElement->isChecked() != otherInputElement->isChecked())
            return false;
        if (thisInputElement->isIndeterminate() != otherInputElement->isIndeterminate())
            return false;

        if (element->isEnabledFormControl() != m_element->isEnabledFormControl())
            return false;

        if (element->isDefaultButtonForForm() != m_element->isDefaultButtonForForm())
            return false;

        if (!m_element->document()->containsValidityStyleRules())
            return false;

        bool willValidate = element->willValidate();

        if (willValidate != m_element->willValidate())
            return false;

        if (willValidate && (element->isValidFormControlElement() != m_element->isValidFormControlElement()))
            return false;

        if (element->isInRange() != m_element->isInRange())
            return false;

        if (element->isOutOfRange() != m_element->isOutOfRange())
            return false;
    }

    if (style->transitions() || style->animations())
        return false;

#if USE(ACCELERATED_COMPOSITING)
    // Turn off style sharing for elements that can gain layers for reasons outside of the style system.
    // See comments in RenderObject::setStyle().
    if (element->hasTagName(iframeTag) || element->hasTagName(frameTag) || element->hasTagName(embedTag) || element->hasTagName(objectTag) || element->hasTagName(appletTag))
        return false;
#endif

    if (equalIgnoringCase(element->fastGetAttribute(dirAttr), "auto") || equalIgnoringCase(m_element->fastGetAttribute(dirAttr), "auto"))
        return false;

    if (element->hasClass() && m_element->fastGetAttribute(classAttr) != element->fastGetAttribute(classAttr))
        return false;

    if (element->hasMappedAttributes() && !element->attributeMap()->mappedMapsEquivalent(m_styledElement->attributeMap()))
        return false;

    if (element->isLink() && m_elementLinkState != style->insideLink())
        return false;

    return true;
}

inline Node* CSSStyleSelector::findSiblingForStyleSharing(Node* node, unsigned& count) const
{
    for (; node; node = node->previousSibling()) {
        if (!node->isElementNode())
            continue;
        if (canShareStyleWithElement(node))
            break;
        if (count++ == cStyleSearchThreshold)
            return 0;
    }
    return node;
}

static inline bool parentStylePreventsSharing(const RenderStyle* parentStyle)
{
    return parentStyle->childrenAffectedByPositionalRules()
        || parentStyle->childrenAffectedByFirstChildRules()
        || parentStyle->childrenAffectedByLastChildRules()
        || parentStyle->childrenAffectedByDirectAdjacentRules();
}

ALWAYS_INLINE RenderStyle* CSSStyleSelector::locateSharedStyle()
{
    if (!m_styledElement || !m_parentStyle)
        return 0;
    // If the element has inline style it is probably unique.
    if (m_styledElement->inlineStyleDecl())
        return 0;
    // Ids stop style sharing if they show up in the stylesheets.
    if (m_styledElement->hasID() && m_features.idsInRules.contains(m_styledElement->idForStyleResolution().impl()))
        return 0;
    if (parentStylePreventsSharing(m_parentStyle))
        return 0;

    // Check previous siblings and their cousins.
    unsigned count = 0;
    unsigned visitedNodeCount = 0;
    Node* shareNode = 0;
    Node* cousinList = m_styledElement->previousSibling();
    while (cousinList) {
        shareNode = findSiblingForStyleSharing(cousinList, count);
        if (shareNode)
            break;
        cousinList = locateCousinList(cousinList->parentElement(), visitedNodeCount);
    }

    // If we have exhausted all our budget or our cousins.
    if (!shareNode)
        return 0;

    // Can't share if sibling rules apply. This is checked at the end as it should rarely fail.
    if (matchesSiblingRules())
        return 0;
    // Tracking child index requires unique style for each node. This may get set by the sibling rule match above.
    if (parentStylePreventsSharing(m_parentStyle))
        return 0;
    return shareNode->renderStyle();
}

void CSSStyleSelector::matchUARules(int& firstUARule, int& lastUARule)
{
    // First we match rules from the user agent sheet.
    RuleSet* userAgentStyleSheet = m_medium->mediaTypeMatchSpecific("print")
        ? defaultPrintStyle : defaultStyle;
    matchRules(userAgentStyleSheet, firstUARule, lastUARule, false);

    // In quirks mode, we match rules from the quirks user agent sheet.
    if (!m_checker.m_strictParsing)
        matchRules(defaultQuirksStyle, firstUARule, lastUARule, false);

    // If document uses view source styles (in view source mode or in xml viewer mode), then we match rules from the view source style sheet.
    if (m_checker.m_document->usesViewSourceStyles()) {
        if (!defaultViewSourceStyle)
            loadViewSourceStyle();
        matchRules(defaultViewSourceStyle, firstUARule, lastUARule, false);
    }
}

PassRefPtr<RenderStyle> CSSStyleSelector::styleForDocument(Document* document)
{
    Frame* frame = document->frame();

    RefPtr<RenderStyle> documentStyle = RenderStyle::create();
    documentStyle->setDisplay(BLOCK);
    documentStyle->setVisuallyOrdered(document->visuallyOrdered());
    documentStyle->setZoom(frame ? frame->pageZoomFactor() : 1);
    documentStyle->setPageScaleTransform(frame ? frame->pageScaleFactor() : 1);
    documentStyle->setUserModify(document->inDesignMode() ? READ_WRITE : READ_ONLY);

    Element* docElement = document->documentElement();
    RenderObject* docElementRenderer = docElement ? docElement->renderer() : 0;
    if (docElementRenderer) {
        // Use the direction and writing-mode of the body to set the
        // viewport's direction and writing-mode unless the property is set on the document element.
        // If there is no body, then use the document element.
        RenderObject* bodyRenderer = document->body() ? document->body()->renderer() : 0;
        if (bodyRenderer && !document->writingModeSetOnDocumentElement())
            documentStyle->setWritingMode(bodyRenderer->style()->writingMode());
        else
            documentStyle->setWritingMode(docElementRenderer->style()->writingMode());
        if (bodyRenderer && !document->directionSetOnDocumentElement())
            documentStyle->setDirection(bodyRenderer->style()->direction());
        else
            documentStyle->setDirection(docElementRenderer->style()->direction());
    }

    FontDescription fontDescription;
    fontDescription.setUsePrinterFont(document->printing());
    if (Settings* settings = document->settings()) {
        fontDescription.setRenderingMode(settings->fontRenderingMode());
        if (document->printing() && !settings->shouldPrintBackgrounds())
            documentStyle->setForceBackgroundsToWhite(true);
        const AtomicString& stdfont = settings->standardFontFamily();
        if (!stdfont.isEmpty()) {
            fontDescription.firstFamily().setFamily(stdfont);
            fontDescription.firstFamily().appendFamily(0);
        }
        fontDescription.setKeywordSize(CSSValueMedium - CSSValueXxSmall + 1);
        int size = CSSStyleSelector::fontSizeForKeyword(document, CSSValueMedium, false);
        fontDescription.setSpecifiedSize(size);
        bool useSVGZoomRules = document->isSVGDocument();
        fontDescription.setComputedSize(CSSStyleSelector::getComputedSizeFromSpecifiedSize(document, documentStyle.get(), fontDescription.isAbsoluteSize(), size, useSVGZoomRules));
    }

    documentStyle->setFontDescription(fontDescription);
    documentStyle->font().update(0);

    return documentStyle.release();
}

// If resolveForRootDefault is true, style based on user agent style sheet only. This is used in media queries, where
// relative units are interpreted according to document root element style, styled only with UA stylesheet

PassRefPtr<RenderStyle> CSSStyleSelector::styleForElement(Element* e, RenderStyle* defaultParent, bool allowSharing, bool resolveForRootDefault, bool matchVisitedPseudoClass)
{
    // 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.
    if (allowSharing && !e->document()->haveStylesheetsLoaded() && !e->renderer()) {
        if (!s_styleNotYetAvailable) {
            s_styleNotYetAvailable = RenderStyle::create().releaseRef();
            s_styleNotYetAvailable->ref();
            s_styleNotYetAvailable->setDisplay(NONE);
            s_styleNotYetAvailable->font().update(m_fontSelector);
        }
        s_styleNotYetAvailable->ref();
        e->document()->setHasNodesWithPlaceholderStyle();
        return s_styleNotYetAvailable;
    }

    initElement(e);
    initForStyleResolve(e, defaultParent);
    if (allowSharing) {
        RenderStyle* sharedStyle = locateSharedStyle();
        if (sharedStyle)
            return sharedStyle;
    }

    // Compute our style allowing :visited to match first.
    RefPtr<RenderStyle> visitedStyle;
    if (!matchVisitedPseudoClass && m_parentStyle && (m_parentStyle->insideLink() || e->isLink()) && e->document()->usesLinkRules()) {
        // Fetch our parent style.
        RenderStyle* parentStyle = m_parentStyle;
        if (!e->isLink()) {
            // Use the parent's visited style if one exists.
            RenderStyle* parentVisitedStyle = m_parentStyle->getCachedPseudoStyle(VISITED_LINK);
            if (parentVisitedStyle)
                parentStyle = parentVisitedStyle;
        }
        visitedStyle = styleForElement(e, parentStyle, false, false, true);
        initForStyleResolve(e, defaultParent);
    }

    m_checker.m_matchVisitedPseudoClass = matchVisitedPseudoClass;

    m_style = RenderStyle::create();

    if (m_parentStyle)
        m_style->inheritFrom(m_parentStyle);
    else {
        m_parentStyle = style();
        // Make sure our fonts are initialized if we don't inherit them from our parent style.
        m_style->font().update(0);
    }

    if (e->isLink()) {
        m_style->setIsLink(true);
        m_style->setInsideLink(m_elementLinkState);
    }

    if (visitedStyle) {
        // Copy any pseudo bits that the visited style has to the primary style so that
        // pseudo element styles will continue to work for pseudo elements inside :visited
        // links.
        for (unsigned pseudo = FIRST_PUBLIC_PSEUDOID; pseudo < FIRST_INTERNAL_PSEUDOID; ++pseudo) {
            if (visitedStyle->hasPseudoStyle(static_cast<PseudoId>(pseudo)))
                m_style->setHasPseudoStyle(static_cast<PseudoId>(pseudo));
        }
        if (m_elementLinkState == InsideUnvisitedLink)
            visitedStyle = 0;  // We made the style to avoid timing attacks. Just throw it away now that we did that, since we don't need it.
        else
            visitedStyle->setStyleType(VISITED_LINK);
    }

    if (simpleDefaultStyleSheet && !elementCanUseSimpleDefaultStyle(e)) {
        loadFullDefaultStyle();
        assertNoSiblingRulesInDefaultStyle();
    }

#if ENABLE(SVG)
    static bool loadedSVGUserAgentSheet;
    if (e->isSVGElement() && !loadedSVGUserAgentSheet) {
        // SVG rules.
        loadedSVGUserAgentSheet = true;
        CSSStyleSheet* svgSheet = parseUASheet(svgUserAgentStyleSheet, sizeof(svgUserAgentStyleSheet));
        defaultStyle->addRulesFromSheet(svgSheet, screenEval());
        defaultPrintStyle->addRulesFromSheet(svgSheet, printEval());
        assertNoSiblingRulesInDefaultStyle();
    }
#endif

#if ENABLE(MATHML)
    static bool loadedMathMLUserAgentSheet;
    if (e->isMathMLElement() && !loadedMathMLUserAgentSheet) {
        // MathML rules.
        loadedMathMLUserAgentSheet = true;
        CSSStyleSheet* mathMLSheet = parseUASheet(mathmlUserAgentStyleSheet, sizeof(mathmlUserAgentStyleSheet));
        defaultStyle->addRulesFromSheet(mathMLSheet, screenEval());
        defaultPrintStyle->addRulesFromSheet(mathMLSheet, printEval());
        // There are some sibling rules here.
        collectSiblingRulesInDefaultStyle();
    }
#endif

#if ENABLE(WML)
    static bool loadedWMLUserAgentSheet;
    if (e->isWMLElement() && !loadedWMLUserAgentSheet) {
        // WML rules.
        loadedWMLUserAgentSheet = true;
        CSSStyleSheet* wmlSheet = parseUASheet(wmlUserAgentStyleSheet, sizeof(wmlUserAgentStyleSheet));
        defaultStyle->addRulesFromSheet(wmlSheet, screenEval());
        defaultPrintStyle->addRulesFromSheet(wmlSheet, printEval());
        assertNoSiblingRulesInDefaultStyle();
    }
#endif

#if ENABLE(VIDEO)
    static bool loadedMediaStyleSheet;
    if (!loadedMediaStyleSheet && (e->hasTagName(videoTag) || e->hasTagName(audioTag))) {
        loadedMediaStyleSheet = true;
        String mediaRules = String(mediaControlsUserAgentStyleSheet, sizeof(mediaControlsUserAgentStyleSheet)) + RenderTheme::themeForPage(e->document()->page())->extraMediaControlsStyleSheet();
        CSSStyleSheet* mediaControlsSheet = parseUASheet(mediaRules);
        defaultStyle->addRulesFromSheet(mediaControlsSheet, screenEval());
        defaultPrintStyle->addRulesFromSheet(mediaControlsSheet, printEval());
        assertNoSiblingRulesInDefaultStyle();
    }
#endif

#if ENABLE(FULLSCREEN_API)
    static bool loadedFullScreenStyleSheet;
    if (!loadedFullScreenStyleSheet && e->document()->webkitIsFullScreen()) {
        loadedFullScreenStyleSheet = true;
        String fullscreenRules = String(fullscreenUserAgentStyleSheet, sizeof(fullscreenUserAgentStyleSheet)) + RenderTheme::defaultTheme()->extraFullScreenStyleSheet();
        CSSStyleSheet* fullscreenSheet = parseUASheet(fullscreenRules);
        defaultStyle->addRulesFromSheet(fullscreenSheet, screenEval());
        defaultQuirksStyle->addRulesFromSheet(fullscreenSheet, screenEval());
    }
#endif

    int firstUARule = -1, lastUARule = -1;
    int firstUserRule = -1, lastUserRule = -1;
    int firstAuthorRule = -1, lastAuthorRule = -1;
    matchUARules(firstUARule, lastUARule);

    if (!resolveForRootDefault) {
        // 4. Now we check user sheet rules.
        if (m_matchAuthorAndUserStyles)
            matchRules(m_userStyle.get(), firstUserRule, lastUserRule, false);

        // 5. Now check author rules, beginning first with presentational attributes
        // mapped from HTML.
        if (m_styledElement) {
            // Ask if the HTML element has mapped attributes.
            if (m_styledElement->hasMappedAttributes()) {
                // Walk our attribute list and add in each decl.
                const NamedNodeMap* map = m_styledElement->attributeMap();
                for (unsigned i = 0; i < map->length(); i++) {
                    Attribute* attr = map->attributeItem(i);
                    if (attr->isMappedAttribute() && attr->decl()) {
                        lastAuthorRule = m_matchedDecls.size();
                        if (firstAuthorRule == -1)
                            firstAuthorRule = lastAuthorRule;
                        addMatchedDeclaration(attr->decl());
                    }
                }
            }

            // Now we check additional mapped declarations.
            // Tables and table cells share an additional mapped rule that must be applied
            // after all attributes, since their mapped style depends on the values of multiple attributes.
            if (m_styledElement->canHaveAdditionalAttributeStyleDecls()) {
                m_additionalAttributeStyleDecls.clear();
                m_styledElement->additionalAttributeStyleDecls(m_additionalAttributeStyleDecls);
                if (!m_additionalAttributeStyleDecls.isEmpty()) {
                    unsigned additionalDeclsSize = m_additionalAttributeStyleDecls.size();
                    if (firstAuthorRule == -1)
                        firstAuthorRule = m_matchedDecls.size();
                    lastAuthorRule = m_matchedDecls.size() + additionalDeclsSize - 1;
                    for (unsigned i = 0; i < additionalDeclsSize; i++)
                        addMatchedDeclaration(m_additionalAttributeStyleDecls[i]);
                }
            }
            if (m_styledElement->isHTMLElement()) {
                bool isAuto;
                TextDirection textDirection = toHTMLElement(m_styledElement)->directionalityIfhasDirAutoAttribute(isAuto);
                if (isAuto)
                    addMatchedDeclaration(textDirection == LTR ? leftToRightDeclaration() : rightToLeftDeclaration());
            }
        }

        // 6. Check the rules in author sheets next.
        if (m_matchAuthorAndUserStyles)
            matchRules(m_authorStyle.get(), firstAuthorRule, lastAuthorRule, false);

        // 7. Now check our inline style attribute.
        if (m_matchAuthorAndUserStyles && m_styledElement) {
            CSSMutableStyleDeclaration* inlineDecl = m_styledElement->inlineStyleDecl();
            if (inlineDecl) {
                lastAuthorRule = m_matchedDecls.size();
                if (firstAuthorRule == -1)
                    firstAuthorRule = lastAuthorRule;
                addMatchedDeclaration(inlineDecl);
            }
        }
    }

    // Reset the value back before applying properties, so that -webkit-link knows what color to use.
    m_checker.m_matchVisitedPseudoClass = matchVisitedPseudoClass;

    // Now we have all of the matched rules in the appropriate order.  Walk the rules and apply
    // high-priority properties first, i.e., those properties that other properties depend on.
    // The order is (1) high-priority not important, (2) high-priority important, (3) normal not important
    // and (4) normal important.
    m_lineHeightValue = 0;
    applyDeclarations<true>(false, 0, m_matchedDecls.size() - 1);
    if (!resolveForRootDefault) {
        applyDeclarations<true>(true, firstAuthorRule, lastAuthorRule);
        applyDeclarations<true>(true, firstUserRule, lastUserRule);
    }
    applyDeclarations<true>(true, firstUARule, lastUARule);

    // If our font got dirtied, go ahead and update it now.
    if (m_fontDirty)
        updateFont();

    // Line-height is set when we are sure we decided on the font-size
    if (m_lineHeightValue)
        applyProperty(CSSPropertyLineHeight, m_lineHeightValue);

    // Now do the normal priority UA properties.
    applyDeclarations<false>(false, firstUARule, lastUARule);

    // Cache our border and background so that we can examine them later.
    cacheBorderAndBackground();

    // Now do the author and user normal priority properties and all the !important properties.
    if (!resolveForRootDefault) {
        applyDeclarations<false>(false, lastUARule + 1, m_matchedDecls.size() - 1);
        applyDeclarations<false>(true, firstAuthorRule, lastAuthorRule);
        applyDeclarations<false>(true, firstUserRule, lastUserRule);
    }
    applyDeclarations<false>(true, firstUARule, lastUARule);

    ASSERT(!m_fontDirty);
    // If our font got dirtied by one of the non-essential font props,
    // go ahead and update it a second time.
    if (m_fontDirty)
        updateFont();

    // Clean up our style object's display and text decorations (among other fixups).
    adjustRenderStyle(style(), m_parentStyle, e);

    // Start loading images referenced by this style.
    loadPendingImages();

    // If we have first-letter pseudo style, do not share this style
    if (m_style->hasPseudoStyle(FIRST_LETTER))
        m_style->setUnique();

    if (visitedStyle) {
        // Add the visited style off the main style.
        m_style->addCachedPseudoStyle(visitedStyle.release());
    }

    if (!matchVisitedPseudoClass)
        initElement(0); // Clear out for the next resolve.

    // Now return the style.
    return m_style.release();
}

PassRefPtr<RenderStyle> CSSStyleSelector::styleForKeyframe(const RenderStyle* elementStyle, const WebKitCSSKeyframeRule* keyframeRule, KeyframeValue& keyframe)
{
    if (keyframeRule->style())
        addMatchedDeclaration(keyframeRule->style());

    ASSERT(!m_style);

    // Create the style
    m_style = RenderStyle::clone(elementStyle);

    m_lineHeightValue = 0;

    // We don't need to bother with !important. Since there is only ever one
    // decl, there's nothing to override. So just add the first properties.
    if (keyframeRule->style())
        applyDeclarations<true>(false, 0, m_matchedDecls.size() - 1);

    // If our font got dirtied, go ahead and update it now.
    if (m_fontDirty)
        updateFont();

    // Line-height is set when we are sure we decided on the font-size
    if (m_lineHeightValue)
        applyProperty(CSSPropertyLineHeight, m_lineHeightValue);

    // Now do rest of the properties.
    if (keyframeRule->style())
        applyDeclarations<false>(false, 0, m_matchedDecls.size() - 1);

    // If our font got dirtied by one of the non-essential font props,
    // go ahead and update it a second time.
    if (m_fontDirty)
        updateFont();

    // Start loading images referenced by this style.
    loadPendingImages();

    // Add all the animating properties to the keyframe.
    if (keyframeRule->style()) {
        CSSMutableStyleDeclaration::const_iterator end = keyframeRule->style()->end();
        for (CSSMutableStyleDeclaration::const_iterator it = keyframeRule->style()->begin(); it != end; ++it) {
            int property = (*it).id();
            // Timing-function within keyframes is special, because it is not animated; it just
            // describes the timing function between this keyframe and the next.
            if (property != CSSPropertyWebkitAnimationTimingFunction)
                keyframe.addProperty(property);
        }
    }

    return m_style.release();
}

void CSSStyleSelector::keyframeStylesForAnimation(Element* e, const RenderStyle* elementStyle, KeyframeList& list)
{
    list.clear();

    // Get the keyframesRule for this name
    if (!e || list.animationName().isEmpty())
        return;

    m_keyframesRuleMap.checkConsistency();

    if (!m_keyframesRuleMap.contains(list.animationName().impl()))
        return;

    const WebKitCSSKeyframesRule* rule = m_keyframesRuleMap.find(list.animationName().impl()).get()->second.get();

    // Construct and populate the style for each keyframe
    for (unsigned i = 0; i < rule->length(); ++i) {
        // Apply the declaration to the style. This is a simplified version of the logic in styleForElement
        initElement(e);
        initForStyleResolve(e);

        const WebKitCSSKeyframeRule* keyframeRule = rule->item(i);

        KeyframeValue keyframe(0, 0);
        keyframe.setStyle(styleForKeyframe(elementStyle, keyframeRule, keyframe));

        // Add this keyframe style to all the indicated key times
        Vector<float> keys;
        keyframeRule->getKeys(keys);
        for (size_t keyIndex = 0; keyIndex < keys.size(); ++keyIndex) {
            keyframe.setKey(keys[keyIndex]);
            list.insert(keyframe);
        }
    }

    // If the 0% keyframe is missing, create it (but only if there is at least one other keyframe)
    int initialListSize = list.size();
    if (initialListSize > 0 && list[0].key() != 0) {
        RefPtr<WebKitCSSKeyframeRule> keyframeRule = WebKitCSSKeyframeRule::create();
        keyframeRule->setKeyText("0%");
        KeyframeValue keyframe(0, 0);
        keyframe.setStyle(styleForKeyframe(elementStyle, keyframeRule.get(), keyframe));
        list.insert(keyframe);
    }

    // If the 100% keyframe is missing, create it (but only if there is at least one other keyframe)
    if (initialListSize > 0 && (list[list.size() - 1].key() != 1)) {
        RefPtr<WebKitCSSKeyframeRule> keyframeRule = WebKitCSSKeyframeRule::create();
        keyframeRule->setKeyText("100%");
        KeyframeValue keyframe(1, 0);
        keyframe.setStyle(styleForKeyframe(elementStyle, keyframeRule.get(), keyframe));
        list.insert(keyframe);
    }
}

PassRefPtr<RenderStyle> CSSStyleSelector::pseudoStyleForElement(PseudoId pseudo, Element* e, RenderStyle* parentStyle, bool matchVisitedPseudoClass)
{
    if (!e)
        return 0;

    initElement(e);

    // Compute our :visited style first, so that we know whether or not we'll need to create a normal style just to hang it
    // off of.
    RefPtr<RenderStyle> visitedStyle;
    if (!matchVisitedPseudoClass && parentStyle && parentStyle->insideLink()) {
        // Fetch our parent style with :visited in effect.
        RenderStyle* parentVisitedStyle = parentStyle->getCachedPseudoStyle(VISITED_LINK);
        visitedStyle = pseudoStyleForElement(pseudo, e, parentVisitedStyle ? parentVisitedStyle : parentStyle, true);
        if (visitedStyle)
            visitedStyle->setStyleType(VISITED_LINK);
    }

    initForStyleResolve(e, parentStyle, pseudo);
    m_style = RenderStyle::create();
    if (parentStyle)
        m_style->inheritFrom(parentStyle);

    m_checker.m_matchVisitedPseudoClass = matchVisitedPseudoClass;

    // Since we don't use pseudo-elements in any of our quirk/print user agent rules, don't waste time walking
    // those rules.

    // Check UA, user and author rules.
    int firstUARule = -1, lastUARule = -1, firstUserRule = -1, lastUserRule = -1, firstAuthorRule = -1, lastAuthorRule = -1;
    matchUARules(firstUARule, lastUARule);

    if (m_matchAuthorAndUserStyles) {
        matchRules(m_userStyle.get(), firstUserRule, lastUserRule, false);
        matchRules(m_authorStyle.get(), firstAuthorRule, lastAuthorRule, false);
    }

    if (m_matchedDecls.isEmpty() && !visitedStyle)
        return 0;

    m_style->setStyleType(pseudo);

    m_lineHeightValue = 0;

    // Reset the value back before applying properties, so that -webkit-link knows what color to use.
    m_checker.m_matchVisitedPseudoClass = matchVisitedPseudoClass;

    // High-priority properties.
    applyDeclarations<true>(false, 0, m_matchedDecls.size() - 1);
    applyDeclarations<true>(true, firstAuthorRule, lastAuthorRule);
    applyDeclarations<true>(true, firstUserRule, lastUserRule);
    applyDeclarations<true>(true, firstUARule, lastUARule);

    // If our font got dirtied, go ahead and update it now.
    if (m_fontDirty)
        updateFont();

    // Line-height is set when we are sure we decided on the font-size
    if (m_lineHeightValue)
        applyProperty(CSSPropertyLineHeight, m_lineHeightValue);

    // Now do the normal priority properties.
    applyDeclarations<false>(false, firstUARule, lastUARule);

    // Cache our border and background so that we can examine them later.
    cacheBorderAndBackground();

    applyDeclarations<false>(false, lastUARule + 1, m_matchedDecls.size() - 1);
    applyDeclarations<false>(true, firstAuthorRule, lastAuthorRule);
    applyDeclarations<false>(true, firstUserRule, lastUserRule);
    applyDeclarations<false>(true, firstUARule, lastUARule);

    // If our font got dirtied by one of the non-essential font props,
    // go ahead and update it a second time.
    if (m_fontDirty)
        updateFont();

    // Clean up our style object's display and text decorations (among other fixups).
    adjustRenderStyle(style(), parentStyle, 0);

    // Start loading images referenced by this style.
    loadPendingImages();

    // Hang our visited style off m_style.
    if (visitedStyle)
        m_style->addCachedPseudoStyle(visitedStyle.release());

    // Now return the style.
    return m_style.release();
}

PassRefPtr<RenderStyle> CSSStyleSelector::styleForPage(int pageIndex)
{
    initForStyleResolve(m_checker.m_document->documentElement()); // m_rootElementStyle will be set to the document style.

    m_style = RenderStyle::create();
    m_style->inheritFrom(m_rootElementStyle);

    const bool isLeft = isLeftPage(pageIndex);
    const bool isFirst = isFirstPage(pageIndex);
    const String page = pageName(pageIndex);
    matchPageRules(defaultPrintStyle, isLeft, isFirst, page);
    matchPageRules(m_userStyle.get(), isLeft, isFirst, page);
    matchPageRules(m_authorStyle.get(), isLeft, isFirst, page);
    m_lineHeightValue = 0;
    applyDeclarations<true>(false, 0, m_matchedDecls.size() - 1);

    // If our font got dirtied, go ahead and update it now.
    if (m_fontDirty)
        updateFont();

    // Line-height is set when we are sure we decided on the font-size
    if (m_lineHeightValue)
        applyProperty(CSSPropertyLineHeight, m_lineHeightValue);

    applyDeclarations<false>(false, 0, m_matchedDecls.size() - 1);

    // Start loading images referenced by this style.
    loadPendingImages();

    // Now return the style.
    return m_style.release();
}

#if ENABLE(DATAGRID)

PassRefPtr<RenderStyle> CSSStyleSelector::pseudoStyleForDataGridColumn(DataGridColumn*, RenderStyle*)
{
    // FIXME: Implement
    return 0;
}

PassRefPtr<RenderStyle> CSSStyleSelector::pseudoStyleForDataGridColumnHeader(DataGridColumn*, RenderStyle*)
{
    // FIXME: Implement
    return 0;
}

#endif

static void addIntrinsicMargins(RenderStyle* style)
{
    // Intrinsic margin value.
    const int intrinsicMargin = 2 * style->effectiveZoom();

    // FIXME: Using width/height alone and not also dealing with min-width/max-width is flawed.
    // FIXME: Using "quirk" to decide the margin wasn't set is kind of lame.
    if (style->width().isIntrinsicOrAuto()) {
        if (style->marginLeft().quirk())
            style->setMarginLeft(Length(intrinsicMargin, Fixed));
        if (style->marginRight().quirk())
            style->setMarginRight(Length(intrinsicMargin, Fixed));
    }

    if (style->height().isAuto()) {
        if (style->marginTop().quirk())
            style->setMarginTop(Length(intrinsicMargin, Fixed));
        if (style->marginBottom().quirk())
            style->setMarginBottom(Length(intrinsicMargin, Fixed));
    }
}

static inline bool isAtShadowBoundary(Element* element)
{
    if (!element)
        return false;

    ContainerNode* parentNode = element->parentNode();
    return parentNode && parentNode->isShadowBoundary();
}

void CSSStyleSelector::adjustRenderStyle(RenderStyle* style, RenderStyle* parentStyle, Element *e)
{
    // Cache our original display.
    style->setOriginalDisplay(style->display());

    if (style->display() != NONE) {
        // If we have a <td> that specifies a float property, in quirks mode we just drop the float
        // property.
        // Sites also commonly use display:inline/block on <td>s and <table>s.  In quirks mode we force
        // these tags to retain their display types.
        if (!m_checker.m_strictParsing && e) {
            if (e->hasTagName(tdTag)) {
                style->setDisplay(TABLE_CELL);
                style->setFloating(FNONE);
            }
            else if (e->hasTagName(tableTag))
                style->setDisplay(style->isDisplayInlineType() ? INLINE_TABLE : TABLE);
        }

        if (e && (e->hasTagName(tdTag) || e->hasTagName(thTag))) {
            if (style->whiteSpace() == KHTML_NOWRAP) {
                // Figure out if we are really nowrapping or if we should just
                // use normal instead.  If the width of the cell is fixed, then
                // we don't actually use NOWRAP.
                if (style->width().isFixed())
                    style->setWhiteSpace(NORMAL);
                else
                    style->setWhiteSpace(NOWRAP);
            }
        }

        // Tables never support the -webkit-* values for text-align and will reset back to the default.
        if (e && e->hasTagName(tableTag) && (style->textAlign() == WEBKIT_LEFT || style->textAlign() == WEBKIT_CENTER || style->textAlign() == WEBKIT_RIGHT))
            style->setTextAlign(TAAUTO);

        // Frames and framesets never honor position:relative or position:absolute.  This is necessary to
        // fix a crash where a site tries to position these objects.  They also never honor display.
        if (e && (e->hasTagName(frameTag) || e->hasTagName(framesetTag))) {
            style->setPosition(StaticPosition);
            style->setDisplay(BLOCK);
        }

        // Table headers with a text-align of auto will change the text-align to center.
        if (e && e->hasTagName(thTag) && style->textAlign() == TAAUTO)
            style->setTextAlign(CENTER);

        if (e && e->hasTagName(legendTag))
            style->setDisplay(BLOCK);

        // Mutate the display to BLOCK or TABLE for certain cases, e.g., if someone attempts to
        // position or float an inline, compact, or run-in.  Cache the original display, since it
        // may be needed for positioned elements that have to compute their static normal flow
        // positions.  We also force inline-level roots to be block-level.
        if (style->display() != BLOCK && style->display() != TABLE && style->display() != BOX &&
            (style->position() == AbsolutePosition || style->position() == FixedPosition || style->floating() != FNONE ||
             (e && e->document()->documentElement() == e))) {
            if (style->display() == INLINE_TABLE)
                style->setDisplay(TABLE);
            else if (style->display() == INLINE_BOX)
                style->setDisplay(BOX);
            else if (style->display() == LIST_ITEM) {
                // It is a WinIE bug that floated list items lose their bullets, so we'll emulate the quirk,
                // but only in quirks mode.
                if (!m_checker.m_strictParsing && style->floating() != FNONE)
                    style->setDisplay(BLOCK);
            }
            else
                style->setDisplay(BLOCK);
        }

        // FIXME: Don't support this mutation for pseudo styles like first-letter or first-line, since it's not completely
        // clear how that should work.
        if (style->display() == INLINE && style->styleType() == NOPSEUDO && parentStyle && style->writingMode() != parentStyle->writingMode())
            style->setDisplay(INLINE_BLOCK);

        // After performing the display mutation, check table rows.  We do not honor position:relative on
        // table rows or cells.  This has been established in CSS2.1 (and caused a crash in containingBlock()
        // on some sites).
        if ((style->display() == TABLE_HEADER_GROUP || style->display() == TABLE_ROW_GROUP
             || style->display() == TABLE_FOOTER_GROUP || style->display() == TABLE_ROW) &&
             style->position() == RelativePosition)
            style->setPosition(StaticPosition);

        // writing-mode does not apply to table row groups, table column groups, table rows, and table columns.
        // FIXME: Table cells should be allowed to be perpendicular or flipped with respect to the table, though.
        if (style->display() == TABLE_COLUMN || style->display() == TABLE_COLUMN_GROUP || style->display() == TABLE_FOOTER_GROUP
            || style->display() == TABLE_HEADER_GROUP || style->display() == TABLE_ROW || style->display() == TABLE_ROW_GROUP
            || style->display() == TABLE_CELL)
            style->setWritingMode(parentStyle->writingMode());

        // FIXME: Since we don't support block-flow on flexible boxes yet, disallow setting
        // of block-flow to anything other than TopToBottomWritingMode.
        // https://bugs.webkit.org/show_bug.cgi?id=46418 - Flexible box support.
        if (style->writingMode() != TopToBottomWritingMode && (style->display() == BOX || style->display() == INLINE_BOX))
            style->setWritingMode(TopToBottomWritingMode);
    }

    // Make sure our z-index value is only applied if the object is positioned.
    if (style->position() == StaticPosition)
        style->setHasAutoZIndex();

    // Auto z-index becomes 0 for the root element and transparent objects.  This prevents
    // cases where objects that should be blended as a single unit end up with a non-transparent
    // object wedged in between them.  Auto z-index also becomes 0 for objects that specify transforms/masks/reflections.
    if (style->hasAutoZIndex() && ((e && e->document()->documentElement() == e) || style->opacity() < 1.0f ||
        style->hasTransformRelatedProperty() || style->hasMask() || style->boxReflect()))
        style->setZIndex(0);

#if ENABLE(WML)
    if (e && (e->hasTagName(WMLNames::insertedLegendTag)
              || e->hasTagName(WMLNames::inputTag))
            && style->width().isAuto())
        style->setWidth(Length(Intrinsic));
#endif

    // Textarea considers overflow visible as auto.
    if (e && e->hasTagName(textareaTag)) {
        style->setOverflowX(style->overflowX() == OVISIBLE ? OAUTO : style->overflowX());
        style->setOverflowY(style->overflowY() == OVISIBLE ? OAUTO : style->overflowY());
    }

    // Finally update our text decorations in effect, but don't allow text-decoration to percolate through
    // tables, inline blocks, inline tables, run-ins, or shadow DOM.
    if (style->display() == TABLE || style->display() == INLINE_TABLE || style->display() == RUN_IN
        || style->display() == INLINE_BLOCK || style->display() == INLINE_BOX || isAtShadowBoundary(e))
        style->setTextDecorationsInEffect(style->textDecoration());
    else
        style->addToTextDecorationsInEffect(style->textDecoration());

    // If either overflow value is not visible, change to auto.
    if (style->overflowX() == OMARQUEE && style->overflowY() != OMARQUEE)
        style->setOverflowY(OMARQUEE);
    else if (style->overflowY() == OMARQUEE && style->overflowX() != OMARQUEE)
        style->setOverflowX(OMARQUEE);
    else if (style->overflowX() == OVISIBLE && style->overflowY() != OVISIBLE)
        style->setOverflowX(OAUTO);
    else if (style->overflowY() == OVISIBLE && style->overflowX() != OVISIBLE)
        style->setOverflowY(OAUTO);

    // Table rows, sections and the table itself will support overflow:hidden and will ignore scroll/auto.
    // FIXME: Eventually table sections will support auto and scroll.
    if (style->display() == TABLE || style->display() == INLINE_TABLE ||
        style->display() == TABLE_ROW_GROUP || style->display() == TABLE_ROW) {
        if (style->overflowX() != OVISIBLE && style->overflowX() != OHIDDEN)
            style->setOverflowX(OVISIBLE);
        if (style->overflowY() != OVISIBLE && style->overflowY() != OHIDDEN)
            style->setOverflowY(OVISIBLE);
    }

    // Menulists should have visible overflow
    if (style->appearance() == MenulistPart) {
        style->setOverflowX(OVISIBLE);
        style->setOverflowY(OVISIBLE);
    }

    // Cull out any useless layers and also repeat patterns into additional layers.
    style->adjustBackgroundLayers();
    style->adjustMaskLayers();

    // Do the same for animations and transitions.
    style->adjustAnimations();
    style->adjustTransitions();

    // Important: Intrinsic margins get added to controls before the theme has adjusted the style, since the theme will
    // alter fonts and heights/widths.
    if (e && e->isFormControlElement() && style->fontSize() >= 11) {
        // Don't apply intrinsic margins to image buttons.  The designer knows how big the images are,
        // so we have to treat all image buttons as though they were explicitly sized.
        if (!e->hasTagName(inputTag) || !static_cast<HTMLInputElement*>(e)->isImageButton())
            addIntrinsicMargins(style);
    }

    // Let the theme also have a crack at adjusting the style.
    if (style->hasAppearance())
        RenderTheme::defaultTheme()->adjustStyle(this, style, e, m_hasUAAppearance, m_borderData, m_backgroundData, m_backgroundColor);

#if ENABLE(SVG)
    if (e && e->isSVGElement()) {
        // Spec: http://www.w3.org/TR/SVG/masking.html#OverflowProperty
        if (style->overflowY() == OSCROLL)
            style->setOverflowY(OHIDDEN);
        else if (style->overflowY() == OAUTO)
            style->setOverflowY(OVISIBLE);

        if (style->overflowX() == OSCROLL)
            style->setOverflowX(OHIDDEN);
        else if (style->overflowX() == OAUTO)
            style->setOverflowX(OVISIBLE);

        // Only the root <svg> element in an SVG document fragment tree honors css position
        if (!(e->hasTagName(SVGNames::svgTag) && e->parentNode() && !e->parentNode()->isSVGElement()))
            style->setPosition(RenderStyle::initialPosition());
    }
#endif
}

void CSSStyleSelector::updateFont()
{
    checkForTextSizeAdjust();
    checkForGenericFamilyChange(style(), m_parentStyle);
    checkForZoomChange(style(), m_parentStyle);
    m_style->font().update(m_fontSelector);
    m_fontDirty = false;
}

void CSSStyleSelector::cacheBorderAndBackground()
{
    m_hasUAAppearance = m_style->hasAppearance();
    if (m_hasUAAppearance) {
        m_borderData = m_style->border();
        m_backgroundData = *m_style->backgroundLayers();
        m_backgroundColor = m_style->backgroundColor();
    }
}

PassRefPtr<CSSRuleList> CSSStyleSelector::styleRulesForElement(Element* e, bool authorOnly, bool includeEmptyRules, CSSRuleFilter filter)
{
    return pseudoStyleRulesForElement(e, NOPSEUDO, authorOnly, includeEmptyRules, filter);
}

PassRefPtr<CSSRuleList> CSSStyleSelector::pseudoStyleRulesForElement(Element* e, PseudoId pseudoId, bool authorOnly, bool includeEmptyRules, CSSRuleFilter filter)
{
    if (!e || !e->document()->haveStylesheetsLoaded())
        return 0;

    m_checker.m_collectRulesOnly = true;

    initElement(e);
    initForStyleResolve(e, 0, pseudoId);

    if (!authorOnly) {
        int firstUARule = -1, lastUARule = -1;
        // First we match rules from the user agent sheet.
        matchUARules(firstUARule, lastUARule);

        // Now we check user sheet rules.
        if (m_matchAuthorAndUserStyles) {
            int firstUserRule = -1, lastUserRule = -1;
            matchRules(m_userStyle.get(), firstUserRule, lastUserRule, includeEmptyRules);
        }
    }

    if (m_matchAuthorAndUserStyles) {
        m_checker.m_sameOriginOnly = (filter == SameOriginCSSRulesOnly);

        // Check the rules in author sheets.
        int firstAuthorRule = -1, lastAuthorRule = -1;
        matchRules(m_authorStyle.get(), firstAuthorRule, lastAuthorRule, includeEmptyRules);

        m_checker.m_sameOriginOnly = false;
    }

    m_checker.m_collectRulesOnly = false;

    return m_ruleList.release();
}

inline bool CSSStyleSelector::checkSelector(const RuleData& ruleData)
{
    m_dynamicPseudo = NOPSEUDO;

    // Let the slow path handle SVG as it has some additional rules regarding shadow trees.
    if (ruleData.hasFastCheckableSelector() && !m_element->isSVGElement()) {
        // We know this selector does not include any pseudo selectors.
        if (m_checker.m_pseudoStyle != NOPSEUDO)
            return false;
        // We know a sufficiently simple single part selector matches simply because we found it from the rule hash.
        // This is limited to HTML only so we don't need to check the namespace.
        if (ruleData.hasTopSelectorMatchingHTMLBasedOnRuleHash() && !ruleData.hasMultipartSelector() && m_element->isHTMLElement())
            return true;
        return SelectorChecker::fastCheckSelector(ruleData.selector(), m_element);
    }

    // Slow path.
    SelectorMatch match = m_checker.checkSelector(ruleData.selector(), m_element, &m_selectorAttrs, m_dynamicPseudo, false, false, style(), m_parentNode ? m_parentNode->renderStyle() : 0);
    if (match != SelectorMatches)
        return false;
    if (m_checker.m_pseudoStyle != NOPSEUDO && m_checker.m_pseudoStyle != m_dynamicPseudo)
        return false;
    return true;
}

static inline bool selectorTagMatches(const Element* element, const CSSSelector* selector)
{
    if (!selector->hasTag())
        return true;
    const AtomicString& localName = selector->tag().localName();
    if (localName != starAtom && localName != element->localName())
        return false;
    const AtomicString& namespaceURI = selector->tag().namespaceURI();
    return namespaceURI == starAtom || namespaceURI == element->namespaceURI();
}

static inline bool isFastCheckableSelector(const CSSSelector* selector)
{
    for (; selector; selector = selector->tagHistory()) {
        if (selector->relation() != CSSSelector::Descendant && selector->relation() != CSSSelector::Child && selector->relation() != CSSSelector::SubSelector)
            return false;
        if (selector->m_match != CSSSelector::None && selector->m_match != CSSSelector::Id && selector->m_match != CSSSelector::Class)
            return false;
    }
    return true;
}

template <class ValueChecker>
inline bool fastCheckSingleSelector(const CSSSelector*& selector, const Element*& element, const CSSSelector*& topChildOrSubselector, const Element*& topChildOrSubselectorMatchElement)
{
    AtomicStringImpl* value = selector->value().impl();
    for (; element; element = element->parentElement()) {
        if (ValueChecker::checkValue(element, value) && selectorTagMatches(element, selector)) {
            if (selector->relation() == CSSSelector::Descendant)
                topChildOrSubselector = 0;
            else if (!topChildOrSubselector) {
                ASSERT(selector->relation() == CSSSelector::Child || selector->relation() == CSSSelector::SubSelector);
                topChildOrSubselector = selector;
                topChildOrSubselectorMatchElement = element;
            }
            if (selector->relation() != CSSSelector::SubSelector)
                element = element->parentElement();
            selector = selector->tagHistory();
            return true;
        }
        if (topChildOrSubselector) {
            // Child or subselector check failed.
            // If the match element is null, topChildOrSubselector was also the very topmost selector and had to match
            // the original element we were checking.
            if (!topChildOrSubselectorMatchElement)
                return false;
            // There may be other matches down the ancestor chain.
            // Rewind to the topmost child or subselector and the element it matched, continue checking ancestors.
            selector = topChildOrSubselector;
            element = topChildOrSubselectorMatchElement->parentElement();
            topChildOrSubselector = 0;
            return true;
        }
    }
    return false;
}

struct ClassCheck {
    static bool checkValue(const Element* element, AtomicStringImpl* value)
    {
        return element->hasClass() && static_cast<const StyledElement*>(element)->classNames().contains(value);
    }
};
struct IdCheck {
    static bool checkValue(const Element* element, AtomicStringImpl* value)
    {
        return element->hasID() && element->idForStyleResolution().impl() == value;
    }
};
struct TagCheck {
    static bool checkValue(const Element*, AtomicStringImpl*)
    {
        return true;
    }
};

bool CSSStyleSelector::SelectorChecker::fastCheckSelector(const CSSSelector* selector, const Element* element)
{
    ASSERT(isFastCheckableSelector(selector));

    // The top selector requires tag check only as rule hashes have already handled id and class matches.
    if (!selectorTagMatches(element, selector))
        return false;

    const CSSSelector* topChildOrSubselector = 0;
    const Element* topChildOrSubselectorMatchElement = 0;
    if (selector->relation() == CSSSelector::Child || selector->relation() == CSSSelector::SubSelector)
        topChildOrSubselector = selector;

    if (selector->relation() != CSSSelector::SubSelector)
        element = element->parentElement();

    selector = selector->tagHistory();

    // We know this compound selector has descendant, child and subselector combinators only and all components are simple.
    while (selector) {
        switch (selector->m_match) {
        case CSSSelector::Class:
            if (!fastCheckSingleSelector<ClassCheck>(selector, element, topChildOrSubselector, topChildOrSubselectorMatchElement))
                return false;
            break;
        case CSSSelector::Id:
            if (!fastCheckSingleSelector<IdCheck>(selector, element, topChildOrSubselector, topChildOrSubselectorMatchElement))
                return false;
            break;
        case CSSSelector::None:
            if (!fastCheckSingleSelector<TagCheck>(selector, element, topChildOrSubselector, topChildOrSubselectorMatchElement))
                return false;
            break;
        default:
            ASSERT_NOT_REACHED();
        }
    }
    return true;
}

// Recursive check of selectors and combinators
// It can return 3 different values:
// * SelectorMatches         - the selector matches the element e
// * SelectorFailsLocally    - the selector fails for the element e
// * SelectorFailsCompletely - the selector fails for e and any sibling or ancestor of e
CSSStyleSelector::SelectorMatch CSSStyleSelector::SelectorChecker::checkSelector(CSSSelector* sel, Element* e, HashSet<AtomicStringImpl*>* selectorAttrs, PseudoId& dynamicPseudo, bool isSubSelector, bool encounteredLink, RenderStyle* elementStyle, RenderStyle* elementParentStyle) const
{
#if ENABLE(SVG)
    // Spec: CSS2 selectors cannot be applied to the (conceptually) cloned DOM tree
    // because its contents are not part of the formal document structure.
    if (e->isSVGElement() && e->isShadowRoot())
        return SelectorFailsCompletely;
#endif

    // first selector has to match
    if (!checkOneSelector(sel, e, selectorAttrs, dynamicPseudo, isSubSelector, encounteredLink, elementStyle, elementParentStyle))
        return SelectorFailsLocally;

    // The rest of the selectors has to match
    CSSSelector::Relation relation = sel->relation();

    // Prepare next sel
    sel = sel->tagHistory();
    if (!sel)
        return SelectorMatches;

    if (relation != CSSSelector::SubSelector)
        // Bail-out if this selector is irrelevant for the pseudoStyle
        if (m_pseudoStyle != NOPSEUDO && m_pseudoStyle != dynamicPseudo)
            return SelectorFailsCompletely;

    // Check for nested links.
    if (m_matchVisitedPseudoClass && !isSubSelector) {
        RenderStyle* currentStyle = elementStyle ? elementStyle : e->renderStyle();
        if (currentStyle && currentStyle->insideLink() && e->isLink()) {
            if (encounteredLink)
                m_matchVisitedPseudoClass = false; // This link is not relevant to the style being resolved, so disable matching.
            else
                encounteredLink = true;
        }
    }

    switch (relation) {
        case CSSSelector::Descendant:
            while (true) {
                ContainerNode* n = e->parentNode();
                if (!n || !n->isElementNode())
                    return SelectorFailsCompletely;
                e = static_cast<Element*>(n);
                SelectorMatch match = checkSelector(sel, e, selectorAttrs, dynamicPseudo, false, encounteredLink);
                if (match != SelectorFailsLocally)
                    return match;
            }
            break;
        case CSSSelector::Child:
        {
            ContainerNode* n = e->parentNode();
            if (!n || !n->isElementNode())
                return SelectorFailsCompletely;
            e = static_cast<Element*>(n);
            return checkSelector(sel, e, selectorAttrs, dynamicPseudo, false, encounteredLink);
        }
        case CSSSelector::DirectAdjacent:
        {
            if (!m_collectRulesOnly && e->parentNode() && e->parentNode()->isElementNode()) {
                RenderStyle* parentStyle = elementStyle ? elementParentStyle : e->parentNode()->renderStyle();
                if (parentStyle)
                    parentStyle->setChildrenAffectedByDirectAdjacentRules();
            }
            Node* n = e->previousSibling();
            while (n && !n->isElementNode())
                n = n->previousSibling();
            if (!n)
                return SelectorFailsLocally;
            e = static_cast<Element*>(n);
            m_matchVisitedPseudoClass = false;
            return checkSelector(sel, e, selectorAttrs, dynamicPseudo, false, encounteredLink);
        }
        case CSSSelector::IndirectAdjacent:
            if (!m_collectRulesOnly && e->parentNode() && e->parentNode()->isElementNode()) {
                RenderStyle* parentStyle = elementStyle ? elementParentStyle : e->parentNode()->renderStyle();
                if (parentStyle)
                    parentStyle->setChildrenAffectedByForwardPositionalRules();
            }
            while (true) {
                Node* n = e->previousSibling();
                while (n && !n->isElementNode())
                    n = n->previousSibling();
                if (!n)
                    return SelectorFailsLocally;
                e = static_cast<Element*>(n);
                m_matchVisitedPseudoClass = false;
                SelectorMatch match = checkSelector(sel, e, selectorAttrs, dynamicPseudo, false, encounteredLink);
                if (match != SelectorFailsLocally)
                    return match;
            };
            break;
        case CSSSelector::SubSelector:
            // a selector is invalid if something follows a pseudo-element
            // We make an exception for scrollbar pseudo elements and allow a set of pseudo classes (but nothing else)
            // to follow the pseudo elements.
            if ((elementStyle || m_collectRulesOnly) && dynamicPseudo != NOPSEUDO && dynamicPseudo != SELECTION &&
                !((RenderScrollbar::scrollbarForStyleResolve() || dynamicPseudo == SCROLLBAR_CORNER || dynamicPseudo == RESIZER) && sel->m_match == CSSSelector::PseudoClass))
                return SelectorFailsCompletely;
            return checkSelector(sel, e, selectorAttrs, dynamicPseudo, true, encounteredLink, elementStyle, elementParentStyle);
        case CSSSelector::ShadowDescendant:
        {
            Node* shadowHostNode = e->shadowAncestorNode();
            if (shadowHostNode == e || !shadowHostNode->isElementNode())
                return SelectorFailsCompletely;
            e = static_cast<Element*>(shadowHostNode);
            return checkSelector(sel, e, selectorAttrs, dynamicPseudo, false, encounteredLink);
        }
    }

    return SelectorFailsCompletely;
}

static void addLocalNameToSet(HashSet<AtomicStringImpl*>* set, const QualifiedName& qName)
{
    set->add(qName.localName().impl());
}

static HashSet<AtomicStringImpl*>* createHtmlCaseInsensitiveAttributesSet()
{
    // This is the list of attributes in HTML 4.01 with values marked as "[CI]" or case-insensitive
    // Mozilla treats all other values as case-sensitive, thus so do we.
    HashSet<AtomicStringImpl*>* attrSet = new HashSet<AtomicStringImpl*>;

    addLocalNameToSet(attrSet, accept_charsetAttr);
    addLocalNameToSet(attrSet, acceptAttr);
    addLocalNameToSet(attrSet, alignAttr);
    addLocalNameToSet(attrSet, alinkAttr);
    addLocalNameToSet(attrSet, axisAttr);
    addLocalNameToSet(attrSet, bgcolorAttr);
    addLocalNameToSet(attrSet, charsetAttr);
    addLocalNameToSet(attrSet, checkedAttr);
    addLocalNameToSet(attrSet, clearAttr);
    addLocalNameToSet(attrSet, codetypeAttr);
    addLocalNameToSet(attrSet, colorAttr);
    addLocalNameToSet(attrSet, compactAttr);
    addLocalNameToSet(attrSet, declareAttr);
    addLocalNameToSet(attrSet, deferAttr);
    addLocalNameToSet(attrSet, dirAttr);
    addLocalNameToSet(attrSet, disabledAttr);
    addLocalNameToSet(attrSet, enctypeAttr);
    addLocalNameToSet(attrSet, faceAttr);
    addLocalNameToSet(attrSet, frameAttr);
    addLocalNameToSet(attrSet, hreflangAttr);
    addLocalNameToSet(attrSet, http_equivAttr);
    addLocalNameToSet(attrSet, langAttr);
    addLocalNameToSet(attrSet, languageAttr);
    addLocalNameToSet(attrSet, linkAttr);
    addLocalNameToSet(attrSet, mediaAttr);
    addLocalNameToSet(attrSet, methodAttr);
    addLocalNameToSet(attrSet, multipleAttr);
    addLocalNameToSet(attrSet, nohrefAttr);
    addLocalNameToSet(attrSet, noresizeAttr);
    addLocalNameToSet(attrSet, noshadeAttr);
    addLocalNameToSet(attrSet, nowrapAttr);
    addLocalNameToSet(attrSet, readonlyAttr);
    addLocalNameToSet(attrSet, relAttr);
    addLocalNameToSet(attrSet, revAttr);
    addLocalNameToSet(attrSet, rulesAttr);
    addLocalNameToSet(attrSet, scopeAttr);
    addLocalNameToSet(attrSet, scrollingAttr);
    addLocalNameToSet(attrSet, selectedAttr);
    addLocalNameToSet(attrSet, shapeAttr);
    addLocalNameToSet(attrSet, targetAttr);
    addLocalNameToSet(attrSet, textAttr);
    addLocalNameToSet(attrSet, typeAttr);
    addLocalNameToSet(attrSet, valignAttr);
    addLocalNameToSet(attrSet, valuetypeAttr);
    addLocalNameToSet(attrSet, vlinkAttr);

    return attrSet;
}

static bool htmlAttributeHasCaseInsensitiveValue(const QualifiedName& attr)
{
    static HashSet<AtomicStringImpl*>* htmlCaseInsensitiveAttributesSet = createHtmlCaseInsensitiveAttributesSet();
    bool isPossibleHTMLAttr = !attr.hasPrefix() && (attr.namespaceURI() == nullAtom);
    return isPossibleHTMLAttr && htmlCaseInsensitiveAttributesSet->contains(attr.localName().impl());
}

bool CSSStyleSelector::SelectorChecker::checkOneSelector(CSSSelector* sel, Element* e, HashSet<AtomicStringImpl*>* selectorAttrs, PseudoId& dynamicPseudo, bool isSubSelector, bool encounteredLink, RenderStyle* elementStyle, RenderStyle* elementParentStyle) const
{
    ASSERT(e);
    if (!e)
        return false;

    if (!selectorTagMatches(e, sel))
        return false;

    if (sel->hasAttribute()) {
        if (sel->m_match == CSSSelector::Class)
            return e->hasClass() && static_cast<StyledElement*>(e)->classNames().contains(sel->value());

        if (sel->m_match == CSSSelector::Id)
            return e->hasID() && e->idForStyleResolution() == sel->value();

        const QualifiedName& attr = sel->attribute();

        // FIXME: Handle the case were elementStyle is 0.
        if (elementStyle && (!e->isStyledElement() || (!static_cast<StyledElement*>(e)->isMappedAttribute(attr) && attr != typeAttr && attr != readonlyAttr))) {
            elementStyle->setAffectedByAttributeSelectors(); // Special-case the "type" and "readonly" attributes so input form controls can share style.
            if (selectorAttrs)
                selectorAttrs->add(attr.localName().impl());
        }

        const AtomicString& value = e->getAttribute(attr);
        if (value.isNull())
            return false; // attribute is not set

        bool caseSensitive = !m_documentIsHTML || !htmlAttributeHasCaseInsensitiveValue(attr);

        switch (sel->m_match) {
        case CSSSelector::Exact:
            if (caseSensitive ? sel->value() != value : !equalIgnoringCase(sel->value(), value))
                return false;
            break;
        case CSSSelector::List:
        {
            // Ignore empty selectors or selectors containing spaces
            if (sel->value().contains(' ') || sel->value().isEmpty())
                return false;

            unsigned startSearchAt = 0;
            while (true) {
                size_t foundPos = value.find(sel->value(), startSearchAt, caseSensitive);
                if (foundPos == notFound)
                    return false;
                if (foundPos == 0 || value[foundPos - 1] == ' ') {
                    unsigned endStr = foundPos + sel->value().length();
                    if (endStr == value.length() || value[endStr] == ' ')
                        break; // We found a match.
                }

                // No match. Keep looking.
                startSearchAt = foundPos + 1;
            }
            break;
        }
        case CSSSelector::Contain:
            if (!value.contains(sel->value(), caseSensitive) || sel->value().isEmpty())
                return false;
            break;
        case CSSSelector::Begin:
            if (!value.startsWith(sel->value(), caseSensitive) || sel->value().isEmpty())
                return false;
            break;
        case CSSSelector::End:
            if (!value.endsWith(sel->value(), caseSensitive) || sel->value().isEmpty())
                return false;
            break;
        case CSSSelector::Hyphen:
            if (value.length() < sel->value().length())
                return false;
            if (!value.startsWith(sel->value(), caseSensitive))
                return false;
            // It they start the same, check for exact match or following '-':
            if (value.length() != sel->value().length() && value[sel->value().length()] != '-')
                return false;
            break;
        case CSSSelector::PseudoClass:
        case CSSSelector::PseudoElement:
        default:
            break;
        }
    }

    if (sel->m_match == CSSSelector::PseudoClass) {
        // Handle :not up front.
        if (sel->pseudoType() == CSSSelector::PseudoNot) {
            ASSERT(sel->selectorList());
            for (CSSSelector* subSel = sel->selectorList()->first(); subSel; subSel = subSel->tagHistory()) {
                // :not cannot nest. I don't really know why this is a
                // restriction in CSS3, but it is, so let's honor it.
                // the parser enforces that this never occurs
                ASSERT(subSel->pseudoType() != CSSSelector::PseudoNot);

                if (!checkOneSelector(subSel, e, selectorAttrs, dynamicPseudo, true, encounteredLink, elementStyle, elementParentStyle))
                    return true;
            }
        } else if (dynamicPseudo != NOPSEUDO && (RenderScrollbar::scrollbarForStyleResolve() || dynamicPseudo == SCROLLBAR_CORNER || dynamicPseudo == RESIZER)) {
            // CSS scrollbars match a specific subset of pseudo classes, and they have specialized rules for each
            // (since there are no elements involved).
            return checkScrollbarPseudoClass(sel, dynamicPseudo);
        } else if (dynamicPseudo == SELECTION) {
            if (sel->pseudoType() == CSSSelector::PseudoWindowInactive)
                return !m_document->page()->focusController()->isActive();
        }

        // Normal element pseudo class checking.
        switch (sel->pseudoType()) {
            // Pseudo classes:
            case CSSSelector::PseudoNot:
                break; // Already handled up above.
            case CSSSelector::PseudoEmpty: {
                bool result = true;
                for (Node* n = e->firstChild(); n; n = n->nextSibling()) {
                    if (n->isElementNode()) {
                        result = false;
                        break;
                    } else if (n->isTextNode()) {
                        Text* textNode = static_cast<Text*>(n);
                        if (!textNode->data().isEmpty()) {
                            result = false;
                            break;
                        }
                    }
                }
                if (!m_collectRulesOnly) {
                    if (elementStyle)
                        elementStyle->setEmptyState(result);
                    else if (e->renderStyle() && (e->document()->usesSiblingRules() || e->renderStyle()->unique()))
                        e->renderStyle()->setEmptyState(result);
                }
                return result;
            }
            case CSSSelector::PseudoFirstChild: {
                // first-child matches the first child that is an element
                if (e->parentNode() && e->parentNode()->isElementNode()) {
                    bool result = false;
                    Node* n = e->previousSibling();
                    while (n && !n->isElementNode())
                        n = n->previousSibling();
                    if (!n)
                        result = true;
                    if (!m_collectRulesOnly) {
                        RenderStyle* childStyle = elementStyle ? elementStyle : e->renderStyle();
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : e->parentNode()->renderStyle();
                        if (parentStyle)
                            parentStyle->setChildrenAffectedByFirstChildRules();
                        if (result && childStyle)
                            childStyle->setFirstChildState();
                    }
                    return result;
                }
                break;
            }
            case CSSSelector::PseudoFirstOfType: {
                // first-of-type matches the first element of its type
                if (e->parentNode() && e->parentNode()->isElementNode()) {
                    bool result = false;
                    const QualifiedName& type = e->tagQName();
                    Node* n = e->previousSibling();
                    while (n) {
                        if (n->isElementNode() && static_cast<Element*>(n)->hasTagName(type))
                            break;
                        n = n->previousSibling();
                    }
                    if (!n)
                        result = true;
                    if (!m_collectRulesOnly) {
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : e->parentNode()->renderStyle();
                        if (parentStyle)
                            parentStyle->setChildrenAffectedByForwardPositionalRules();
                    }
                    return result;
                }
                break;
            }
            case CSSSelector::PseudoLastChild: {
                // last-child matches the last child that is an element
                if (Element* parentElement = e->parentElement()) {
                    bool result = false;
                    if (parentElement->isFinishedParsingChildren()) {
                        Node* n = e->nextSibling();
                        while (n && !n->isElementNode())
                            n = n->nextSibling();
                        if (!n)
                            result = true;
                    }
                    if (!m_collectRulesOnly) {
                        RenderStyle* childStyle = elementStyle ? elementStyle : e->renderStyle();
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : parentElement->renderStyle();
                        if (parentStyle)
                            parentStyle->setChildrenAffectedByLastChildRules();
                        if (result && childStyle)
                            childStyle->setLastChildState();
                    }
                    return result;
                }
                break;
            }
            case CSSSelector::PseudoLastOfType: {
                // last-of-type matches the last element of its type
                if (Element* parentElement = e->parentElement()) {
                    if (!m_collectRulesOnly) {
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : parentElement->renderStyle();
                        if (parentStyle)
                            parentStyle->setChildrenAffectedByBackwardPositionalRules();
                    }
                    if (!parentElement->isFinishedParsingChildren())
                        return false;
                    bool result = false;
                    const QualifiedName& type = e->tagQName();
                    Node* n = e->nextSibling();
                    while (n) {
                        if (n->isElementNode() && static_cast<Element*>(n)->hasTagName(type))
                            break;
                        n = n->nextSibling();
                    }
                    if (!n)
                        result = true;
                    return result;
                }
                break;
            }
            case CSSSelector::PseudoOnlyChild: {
                if (Element* parentElement = e->parentElement()) {
                    bool firstChild = false;
                    bool lastChild = false;

                    Node* n = e->previousSibling();
                    while (n && !n->isElementNode())
                        n = n->previousSibling();
                    if (!n)
                        firstChild = true;
                    if (firstChild && parentElement->isFinishedParsingChildren()) {
                        n = e->nextSibling();
                        while (n && !n->isElementNode())
                            n = n->nextSibling();
                        if (!n)
                            lastChild = true;
                    }
                    if (!m_collectRulesOnly) {
                        RenderStyle* childStyle = elementStyle ? elementStyle : e->renderStyle();
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : parentElement->renderStyle();
                        if (parentStyle) {
                            parentStyle->setChildrenAffectedByFirstChildRules();
                            parentStyle->setChildrenAffectedByLastChildRules();
                        }
                        if (firstChild && childStyle)
                            childStyle->setFirstChildState();
                        if (lastChild && childStyle)
                            childStyle->setLastChildState();
                    }
                    return firstChild && lastChild;
                }
                break;
            }
            case CSSSelector::PseudoOnlyOfType: {
                // FIXME: This selector is very slow.
                if (Element* parentElement = e->parentElement()) {
                    if (!m_collectRulesOnly) {
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : parentElement->renderStyle();
                        if (parentStyle) {
                            parentStyle->setChildrenAffectedByForwardPositionalRules();
                            parentStyle->setChildrenAffectedByBackwardPositionalRules();
                        }
                    }
                    if (!parentElement->isFinishedParsingChildren())
                        return false;
                    bool firstChild = false;
                    bool lastChild = false;
                    const QualifiedName& type = e->tagQName();
                    Node* n = e->previousSibling();
                    while (n) {
                        if (n->isElementNode() && static_cast<Element*>(n)->hasTagName(type))
                            break;
                        n = n->previousSibling();
                    }
                    if (!n)
                        firstChild = true;
                    if (firstChild) {
                        n = e->nextSibling();
                        while (n) {
                            if (n->isElementNode() && static_cast<Element*>(n)->hasTagName(type))
                                break;
                            n = n->nextSibling();
                        }
                        if (!n)
                            lastChild = true;
                    }
                    return firstChild && lastChild;
                }
                break;
            }
            case CSSSelector::PseudoNthChild: {
                if (!sel->parseNth())
                    break;
                if (Element* parentElement = e->parentElement()) {
                    int count = 1;
                    Node* n = e->previousSibling();
                    while (n) {
                        if (n->isElementNode()) {
                            RenderStyle* s = n->renderStyle();
                            unsigned index = s ? s->childIndex() : 0;
                            if (index) {
                                count += index;
                                break;
                            }
                            count++;
                        }
                        n = n->previousSibling();
                    }

                    if (!m_collectRulesOnly) {
                        RenderStyle* childStyle = elementStyle ? elementStyle : e->renderStyle();
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : parentElement->renderStyle();
                        if (childStyle)
                            childStyle->setChildIndex(count);
                        if (parentStyle)
                            parentStyle->setChildrenAffectedByForwardPositionalRules();
                    }

                    if (sel->matchNth(count))
                        return true;
                }
                break;
            }
            case CSSSelector::PseudoNthOfType: {
                if (!sel->parseNth())
                    break;
                if (Element* parentElement = e->parentElement()) {
                    int count = 1;
                    const QualifiedName& type = e->tagQName();
                    Node* n = e->previousSibling();
                    while (n) {
                        if (n->isElementNode() && static_cast<Element*>(n)->hasTagName(type))
                            count++;
                        n = n->previousSibling();
                    }

                    if (!m_collectRulesOnly) {
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : parentElement->renderStyle();
                        if (parentStyle)
                            parentStyle->setChildrenAffectedByForwardPositionalRules();
                    }

                    if (sel->matchNth(count))
                        return true;
                }
                break;
            }
            case CSSSelector::PseudoNthLastChild: {
                if (!sel->parseNth())
                    break;
                if (Element* parentElement = e->parentElement()) {
                    if (!m_collectRulesOnly) {
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : parentElement->renderStyle();
                        if (parentStyle)
                            parentStyle->setChildrenAffectedByBackwardPositionalRules();
                    }
                    if (!parentElement->isFinishedParsingChildren())
                        return false;
                    int count = 1;
                    Node* n = e->nextSibling();
                    while (n) {
                        if (n->isElementNode())
                            count++;
                        n = n->nextSibling();
                    }
                    if (sel->matchNth(count))
                        return true;
                }
                break;
            }
            case CSSSelector::PseudoNthLastOfType: {
                if (!sel->parseNth())
                    break;
                if (Element* parentElement = e->parentElement()) {
                    if (!m_collectRulesOnly) {
                        RenderStyle* parentStyle = elementStyle ? elementParentStyle : parentElement->renderStyle();
                        if (parentStyle)
                            parentStyle->setChildrenAffectedByBackwardPositionalRules();
                    }
                    if (!parentElement->isFinishedParsingChildren())
                        return false;
                    int count = 1;
                    const QualifiedName& type = e->tagQName();
                    Node* n = e->nextSibling();
                    while (n) {
                        if (n->isElementNode() && static_cast<Element*>(n)->hasTagName(type))
                            count++;
                        n = n->nextSibling();
                    }
                    if (sel->matchNth(count))
                        return true;
                }
                break;
            }
            case CSSSelector::PseudoTarget:
                if (e == e->document()->cssTarget())
                    return true;
                break;
            case CSSSelector::PseudoAny:
                for (CSSSelector* selector = sel->selectorList()->first(); selector; selector = CSSSelectorList::next(selector)) {
                    if (checkSelector(selector, e, selectorAttrs, dynamicPseudo, true, encounteredLink, elementStyle, elementParentStyle) == SelectorMatches)
                        return true;
                }
                break;
            case CSSSelector::PseudoAnyLink:
                if (e && e->isLink())
                    return true;
                break;
            case CSSSelector::PseudoAutofill: {
                if (!e || !e->isFormControlElement())
                    break;
                if (InputElement* inputElement = e->toInputElement())
                    return inputElement->isAutofilled();
                break;
            }
            case CSSSelector::PseudoLink:
                if (e && e->isLink())
                    return !m_matchVisitedPseudoClass;
                break;
            case CSSSelector::PseudoVisited:
                if (e && e->isLink())
                    return m_matchVisitedPseudoClass;
                break;
            case CSSSelector::PseudoDrag: {
                if (elementStyle)
                    elementStyle->setAffectedByDragRules(true);
                else if (e->renderStyle())
                    e->renderStyle()->setAffectedByDragRules(true);
                if (e->renderer() && e->renderer()->isDragging())
                    return true;
                break;
            }
            case CSSSelector::PseudoFocus:
                if (e && e->focused() && e->document()->frame() && e->document()->frame()->selection()->isFocusedAndActive())
                    return true;
                break;
            case CSSSelector::PseudoHover: {
                // If we're in quirks mode, then hover should never match anchors with no
                // href and *:hover should not match anything.  This is important for sites like wsj.com.
                if (m_strictParsing || isSubSelector || (sel->hasTag() && !e->hasTagName(aTag)) || e->isLink()) {
                    if (elementStyle)
                        elementStyle->setAffectedByHoverRules(true);
                    else if (e->renderStyle())
                        e->renderStyle()->setAffectedByHoverRules(true);
                    if (e->hovered())
                        return true;
                }
                break;
            }
            case CSSSelector::PseudoActive:
                // If we're in quirks mode, then :active should never match anchors with no
                // href and *:active should not match anything.
                if (m_strictParsing || isSubSelector || (sel->hasTag() && !e->hasTagName(aTag)) || e->isLink()) {
                    if (elementStyle)
                        elementStyle->setAffectedByActiveRules(true);
                    else if (e->renderStyle())
                        e->renderStyle()->setAffectedByActiveRules(true);
                    if (e->active())
                        return true;
                }
                break;
            case CSSSelector::PseudoEnabled:
                if (e && e->isFormControlElement())
                    return e->isEnabledFormControl();
                break;
            case CSSSelector::PseudoFullPageMedia:
                return e && e->document() && e->document()->isMediaDocument();
                break;
            case CSSSelector::PseudoDefault:
                return e && e->isDefaultButtonForForm();
            case CSSSelector::PseudoDisabled:
                if (e && e->isFormControlElement())
                    return !e->isEnabledFormControl();
                break;
            case CSSSelector::PseudoReadOnly: {
                if (!e || !e->isFormControlElement())
                    return false;
                return e->isTextFormControl() && e->isReadOnlyFormControl();
            }
            case CSSSelector::PseudoReadWrite: {
                if (!e || !e->isFormControlElement())
                    return false;
                return e->isTextFormControl() && !e->isReadOnlyFormControl();
            }
            case CSSSelector::PseudoOptional:
                return e && e->isOptionalFormControl();
            case CSSSelector::PseudoRequired:
                return e && e->isRequiredFormControl();
            case CSSSelector::PseudoValid: {
                if (!e)
                    return false;
                e->document()->setContainsValidityStyleRules();
                return e->willValidate() && e->isValidFormControlElement();
            } case CSSSelector::PseudoInvalid: {
                if (!e)
                    return false;
                e->document()->setContainsValidityStyleRules();
                return (e->willValidate() && !e->isValidFormControlElement()) || e->hasUnacceptableValue();
            } case CSSSelector::PseudoChecked: {
                if (!e || !e->isFormControlElement())
                    break;
                // Even though WinIE allows checked and indeterminate to co-exist, the CSS selector spec says that
                // you can't be both checked and indeterminate.  We will behave like WinIE behind the scenes and just
                // obey the CSS spec here in the test for matching the pseudo.
                InputElement* inputElement = e->toInputElement();
                if (inputElement && inputElement->isChecked() && !inputElement->isIndeterminate())
                    return true;
                break;
            }
            case CSSSelector::PseudoIndeterminate: {
                if (!e || !e->isFormControlElement())
                    break;
                InputElement* inputElement = e->toInputElement();
                if (inputElement && inputElement->isIndeterminate())
                    return true;
                break;
            }
            case CSSSelector::PseudoRoot:
                if (e == e->document()->documentElement())
                    return true;
                break;
            case CSSSelector::PseudoLang: {
                AtomicString value = e->computeInheritedLanguage();
                const AtomicString& argument = sel->argument();
                if (value.isEmpty() || !value.startsWith(argument, false))
                    break;
                if (value.length() != argument.length() && value[argument.length()] != '-')
                    break;
                return true;
            }
#if ENABLE(FULLSCREEN_API)
            case CSSSelector::PseudoFullScreen:
                // While a Document is in the fullscreen state, and the document's current fullscreen
                // element is an element in the document, the 'full-screen' pseudoclass applies to
                // that element. Also, an <iframe>, <object> or <embed> element whose child browsing
                // context's Document is in the fullscreen state has the 'full-screen' pseudoclass applied.
                if (!e->document()->webkitIsFullScreen())
                    return false;
                if (e != e->document()->webkitCurrentFullScreenElement())
                    return false;
                return true;
            case CSSSelector::PseudoFullScreenDocument:
                // While a Document is in the fullscreen state, the 'full-screen-document' pseudoclass applies
                // t