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   1 /*
   2  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
   3  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
   4  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
   5  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Apple Inc. All rights reserved.
   6  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
   7  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
   8  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
   9  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  10  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  11  *
  12  * This library is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU Library General Public
  14  * License as published by the Free Software Foundation; either
  15  * version 2 of the License, or (at your option) any later version.
  16  *
  17  * This library is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public License
  23  * along with this library; see the file COPYING.LIB.  If not, write to
  24  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  25  * Boston, MA 02110-1301, USA.
  26  */
  27
  28 #include "config.h"
  29 #include "SelectorChecker.h"
  30
  31 #include "CSSSelector.h"
  32 #include "CSSSelectorList.h"
  33 #include "Document.h"
  34 #include "ElementTraversal.h"
  35 #include "FocusController.h"
  36 #include "Frame.h"
  37 #include "FrameSelection.h"
  38 #include "HTMLAnchorElement.h"
  39 #include "HTMLDocument.h"
  40 #include "HTMLFrameElementBase.h"
  41 #include "HTMLInputElement.h"
  42 #include "HTMLNames.h"
  43 #include "HTMLOptGroupElement.h"
  44 #include "HTMLOptionElement.h"
  45 #include "HTMLProgressElement.h"
  46 #include "HTMLStyleElement.h"
  47 #include "InsertionPoint.h"
  48 #include "InspectorInstrumentation.h"
  49 #include "NodeRenderStyle.h"
  50 #include "Page.h"
  51 #include "RenderElement.h"
  52 #include "RenderScrollbar.h"
  53 #include "RenderStyle.h"
  54 #include "ScrollableArea.h"
  55 #include "ScrollbarTheme.h"
  56 #include "SelectorCheckerTestFunctions.h"
  57 #include "ShadowRoot.h"
  58 #include "StyledElement.h"
  59 #include "Text.h"
  60
  61 namespace WebCore {
  62
  63 using namespace HTMLNames;
  64
  65 static inline bool isFirstChildElement(const Element* element)
  66 {
  67     return !ElementTraversal::previousSibling(element);
  68 }
  69
  70 static inline bool isLastChildElement(const Element* element)
  71 {
  72     return !ElementTraversal::nextSibling(element);
  73 }
  74
  75 static inline bool isFirstOfType(const Element* element, const QualifiedName& type)
  76 {
  77     for (const Element* sibling = ElementTraversal::previousSibling(element); sibling; sibling = ElementTraversal::previousSibling(sibling)) {
  78         if (sibling->hasTagName(type))
  79             return false;
  80     }
  81     return true;
  82 }
  83
  84 static inline bool isLastOfType(const Element* element, const QualifiedName& type)
  85 {
  86     for (const Element* sibling = ElementTraversal::nextSibling(element); sibling; sibling = ElementTraversal::nextSibling(sibling)) {
  87         if (sibling->hasTagName(type))
  88             return false;
  89     }
  90     return true;
  91 }
  92
  93 static inline int countElementsBefore(const Element* element)
  94 {
  95     int count = 0;
  96     for (const Element* sibling = ElementTraversal::previousSibling(element); sibling; sibling = ElementTraversal::previousSibling(sibling)) {
  97         unsigned index = sibling->childIndex();
  98         if (index) {
  99             count += index;
 100             break;
 101         }
 102         count++;
 103     }
 104     return count;
 105 }
 106
 107 static inline int countElementsOfTypeBefore(const Element* element, const QualifiedName& type)
 108 {
 109     int count = 0;
 110     for (const Element* sibling = ElementTraversal::previousSibling(element); sibling; sibling = ElementTraversal::previousSibling(sibling)) {
 111         if (sibling->hasTagName(type))
 112             ++count;
 113     }
 114     return count;
 115 }
 116
 117 static inline int countElementsAfter(const Element* element)
 118 {
 119     int count = 0;
 120     for (const Element* sibling = ElementTraversal::nextSibling(element); sibling; sibling = ElementTraversal::nextSibling(sibling))
 121         ++count;
 122     return count;
 123 }
 124
 125 static inline int countElementsOfTypeAfter(const Element* element, const QualifiedName& type)
 126 {
 127     int count = 0;
 128     for (const Element* sibling = ElementTraversal::nextSibling(element); sibling; sibling = ElementTraversal::nextSibling(sibling)) {
 129         if (sibling->hasTagName(type))
 130             ++count;
 131     }
 132     return count;
 133 }
 134
 135 SelectorChecker::SelectorChecker(Document& document, Mode mode)
 136     : m_strictParsing(!document.inQuirksMode())
 137     , m_documentIsHTML(document.isHTMLDocument())
 138     , m_mode(mode)
 139 {
 140 }
 141
 142 bool SelectorChecker::match(const SelectorCheckingContext& context) const
 143 {
 144     PseudoId pseudoId = NOPSEUDO;
 145     if (matchRecursively(context, pseudoId) != SelectorMatches)
 146         return false;
 147     if (context.pseudoId != NOPSEUDO && context.pseudoId != pseudoId)
 148         return false;
 149     if (context.pseudoId == NOPSEUDO && pseudoId != NOPSEUDO) {
 150         if (m_mode == ResolvingStyle && pseudoId < FIRST_INTERNAL_PSEUDOID)
 151             context.elementStyle->setHasPseudoStyle(pseudoId);
 152
 153         // For SharingRules testing, any match is good enough, we don't care what is matched.
 154         return m_mode == SharingRules || m_mode == StyleInvalidation;
 155     }
 156     return true;
 157 }
 158
 159 // Recursive check of selectors and combinators
 160 // It can return 4 different values:
 161 // * SelectorMatches          - the selector matches the element e
 162 // * SelectorFailsLocally     - the selector fails for the element e
 163 // * SelectorFailsAllSiblings - the selector fails for e and any sibling of e
 164 // * SelectorFailsCompletely  - the selector fails for e and any sibling or ancestor of e
 165 SelectorChecker::Match SelectorChecker::matchRecursively(const SelectorCheckingContext& context, PseudoId& dynamicPseudo) const
 166 {
 167     // The first selector has to match.
 168     if (!checkOne(context))
 169         return SelectorFailsLocally;
 170
 171     if (context.selector->m_match == CSSSelector::PseudoElement) {
 172         if (context.selector->isCustomPseudoElement()) {
 173             if (ShadowRoot* root = context.element->containingShadowRoot()) {
 174                 if (context.element->shadowPseudoId() != context.selector->value())
 175                     return SelectorFailsLocally;
 176
 177                 if (context.selector->pseudoElementType() == CSSSelector::PseudoElementWebKitCustom && root->type() != ShadowRoot::UserAgentShadowRoot)
 178                     return SelectorFailsLocally;
 179             } else if (m_mode != StyleInvalidation)
 180                 return SelectorFailsLocally;
 181         } else {
 182             if ((!context.elementStyle && m_mode == ResolvingStyle) || m_mode == QueryingRules)
 183                 return SelectorFailsLocally;
 184
 185             // When invalidating style all pseudo elements need to match.
 186             PseudoId pseudoId = m_mode == StyleInvalidation ? NOPSEUDO : CSSSelector::pseudoId(context.selector->pseudoElementType());
 187             if (pseudoId != NOPSEUDO) {
 188                 dynamicPseudo = pseudoId;
 189
 190                 if (pseudoId == FIRST_LETTER)
 191                     context.element->document().styleSheetCollection().setUsesFirstLetterRules(true);
 192             }
 193         }
 194     }
 195
 196     // The rest of the selectors has to match
 197     CSSSelector::Relation relation = context.selector->relation();
 198
 199     // Prepare next selector
 200     const CSSSelector* historySelector = context.selector->tagHistory();
 201     if (!historySelector)
 202         return SelectorMatches;
 203
 204     SelectorCheckingContext nextContext(context);
 205     nextContext.selector = historySelector;
 206
 207     PseudoId ignoreDynamicPseudo = NOPSEUDO;
 208     if (relation != CSSSelector::SubSelector) {
 209         // Bail-out if this selector is irrelevant for the pseudoId
 210         if (context.pseudoId != NOPSEUDO && context.pseudoId != dynamicPseudo)
 211             return SelectorFailsCompletely;
 212
 213         // Disable :visited matching when we see the first link or try to match anything else than an ancestors.
 214         if (context.firstSelectorOfTheFragment == context.selector && (context.element->isLink() || (relation != CSSSelector::Descendant && relation != CSSSelector::Child)))
 215             nextContext.visitedMatchType = VisitedMatchDisabled;
 216
 217         nextContext.pseudoId = NOPSEUDO;
 218     }
 219
 220     switch (relation) {
 221     case CSSSelector::Descendant:
 222         nextContext.element = context.element->parentElement();
 223         nextContext.firstSelectorOfTheFragment = nextContext.selector;
 224         nextContext.elementStyle = 0;
 225         for (; nextContext.element; nextContext.element = nextContext.element->parentElement()) {
 226             Match match = this->matchRecursively(nextContext, ignoreDynamicPseudo);
 227             if (match == SelectorMatches || match == SelectorFailsCompletely)
 228                 return match;
 229         }
 230         return SelectorFailsCompletely;
 231
 232     case CSSSelector::Child:
 233         {
 234             nextContext.element = context.element->parentElement();
 235             if (!nextContext.element)
 236                 return SelectorFailsCompletely;
 237             nextContext.firstSelectorOfTheFragment = nextContext.selector;
 238             nextContext.elementStyle = nullptr;
 239             Match match = matchRecursively(nextContext, ignoreDynamicPseudo);
 240             if (match == SelectorMatches || match == SelectorFailsCompletely)
 241                 return match;
 242             return SelectorFailsAllSiblings;
 243         }
 244
 245     case CSSSelector::DirectAdjacent:
 246         if (m_mode == ResolvingStyle) {
 247             if (Element* parentElement = context.element->parentElement())
 248                 parentElement->setChildrenAffectedByDirectAdjacentRules();
 249         }
 250         nextContext.element = context.element->previousElementSibling();
 251         if (!nextContext.element)
 252             return SelectorFailsAllSiblings;
 253         nextContext.firstSelectorOfTheFragment = nextContext.selector;
 254         nextContext.elementStyle = 0;
 255         return matchRecursively(nextContext, ignoreDynamicPseudo);
 256
 257     case CSSSelector::IndirectAdjacent:
 258         if (m_mode == ResolvingStyle) {
 259             if (Element* parentElement = context.element->parentElement())
 260                 parentElement->setChildrenAffectedByForwardPositionalRules();
 261         }
 262         nextContext.element = context.element->previousElementSibling();
 263         nextContext.firstSelectorOfTheFragment = nextContext.selector;
 264         nextContext.elementStyle = 0;
 265         for (; nextContext.element; nextContext.element = nextContext.element->previousElementSibling()) {
 266             Match match = this->matchRecursively(nextContext, ignoreDynamicPseudo);
 267             if (match == SelectorMatches || match == SelectorFailsAllSiblings || match == SelectorFailsCompletely)
 268                 return match;
 269         };
 270         return SelectorFailsAllSiblings;
 271
 272     case CSSSelector::SubSelector:
 273         // a selector is invalid if something follows a pseudo-element
 274         // We make an exception for scrollbar pseudo elements and allow a set of pseudo classes (but nothing else)
 275         // to follow the pseudo elements.
 276         nextContext.hasScrollbarPseudo = dynamicPseudo != NOPSEUDO && (context.scrollbar || dynamicPseudo == SCROLLBAR_CORNER || dynamicPseudo == RESIZER);
 277         nextContext.hasSelectionPseudo = dynamicPseudo == SELECTION;
 278         if ((context.elementStyle || m_mode == CollectingRules || m_mode == QueryingRules) && dynamicPseudo != NOPSEUDO
 279             && !nextContext.hasSelectionPseudo
 280             && !(nextContext.hasScrollbarPseudo && nextContext.selector->m_match == CSSSelector::PseudoClass))
 281             return SelectorFailsCompletely;
 282         return matchRecursively(nextContext, dynamicPseudo);
 283
 284     case CSSSelector::ShadowDescendant:
 285         {
 286             Element* shadowHostNode = context.element->shadowHost();
 287             if (!shadowHostNode)
 288                 return SelectorFailsCompletely;
 289             nextContext.element = shadowHostNode;
 290             nextContext.firstSelectorOfTheFragment = nextContext.selector;
 291             nextContext.elementStyle = 0;
 292             return matchRecursively(nextContext, ignoreDynamicPseudo);
 293         }
 294     }
 295
 296     ASSERT_NOT_REACHED();
 297     return SelectorFailsCompletely;
 298 }
 299
 300 static bool attributeValueMatches(const Attribute& attribute, CSSSelector::Match match, const AtomicString& selectorValue, bool caseSensitive)
 301 {
 302     const AtomicString& value = attribute.value();
 303     ASSERT(!value.isNull());
 304
 305     switch (match) {
 306     case CSSSelector::Set:
 307         break;
 308     case CSSSelector::Exact:
 309         if (caseSensitive ? selectorValue != value : !equalIgnoringCase(selectorValue, value))
 310             return false;
 311         break;
 312     case CSSSelector::List:
 313         {
 314             // Ignore empty selectors or selectors containing spaces
 315             if (selectorValue.contains(' ') || selectorValue.isEmpty())
 316                 return false;
 317
 318             unsigned startSearchAt = 0;
 319             while (true) {
 320                 size_t foundPos = value.find(selectorValue, startSearchAt, caseSensitive);
 321                 if (foundPos == notFound)
 322                     return false;
 323                 if (!foundPos || value[foundPos - 1] == ' ') {
 324                     unsigned endStr = foundPos + selectorValue.length();
 325                     if (endStr == value.length() || value[endStr] == ' ')
 326                         break; // We found a match.
 327                 }
 328
 329                 // No match. Keep looking.
 330                 startSearchAt = foundPos + 1;
 331             }
 332             break;
 333         }
 334     case CSSSelector::Contain:
 335         if (!value.contains(selectorValue, caseSensitive) || selectorValue.isEmpty())
 336             return false;
 337         break;
 338     case CSSSelector::Begin:
 339         if (!value.startsWith(selectorValue, caseSensitive) || selectorValue.isEmpty())
 340             return false;
 341         break;
 342     case CSSSelector::End:
 343         if (!value.endsWith(selectorValue, caseSensitive) || selectorValue.isEmpty())
 344             return false;
 345         break;
 346     case CSSSelector::Hyphen:
 347         if (value.length() < selectorValue.length())
 348             return false;
 349         if (!value.startsWith(selectorValue, caseSensitive))
 350             return false;
 351         // It they start the same, check for exact match or following '-':
 352         if (value.length() != selectorValue.length() && value[selectorValue.length()] != '-')
 353             return false;
 354         break;
 355     default:
 356         ASSERT_NOT_REACHED();
 357         return false;
 358     }
 359
 360     return true;
 361 }
 362
 363 static bool anyAttributeMatches(Element* element, const CSSSelector* selector, const QualifiedName& selectorAttr, bool caseSensitive)
 364 {
 365     ASSERT(element->hasAttributesWithoutUpdate());
 366     for (const Attribute& attribute : element->attributesIterator()) {
 367         if (!attribute.matches(selectorAttr.prefix(), element->isHTMLElement() ? selector->attributeCanonicalLocalName() : selectorAttr.localName(), selectorAttr.namespaceURI()))
 368             continue;
 369
 370         if (attributeValueMatches(attribute, static_cast<CSSSelector::Match>(selector->m_match), selector->value(), caseSensitive))
 371             return true;
 372     }
 373
 374     return false;
 375 }
 376
 377 static bool canMatchHoverOrActiveInQuirksMode(const SelectorChecker::SelectorCheckingContext& context)
 378 {
 379     // For quirks mode, follow this: http://quirks.spec.whatwg.org/#the-:active-and-:hover-quirk
 380     // In quirks mode, a compound selector 'selector' that matches the following conditions must not match elements that would not also match the ':any-link' selector.
 381     //
 382     //    selector uses the ':active' or ':hover' pseudo-classes.
 383     //    selector does not use a type selector.
 384     //    selector does not use an attribute selector.
 385     //    selector does not use an ID selector.
 386     //    selector does not use a class selector.
 387     //    selector does not use a pseudo-class selector other than ':active' and ':hover'.
 388     //    selector does not use a pseudo-element selector.
 389     //    selector is not part of an argument to a functional pseudo-class or pseudo-element.
 390     if (context.inFunctionalPseudoClass)
 391         return true;
 392
 393     for (const CSSSelector* selector = context.firstSelectorOfTheFragment; selector; selector = selector->tagHistory()) {
 394         switch (selector->m_match) {
 395         case CSSSelector::Tag:
 396             if (selector->tagQName() != anyQName())
 397                 return true;
 398             break;
 399         case CSSSelector::PseudoClass: {
 400             CSSSelector::PseudoClassType pseudoClassType = selector->pseudoClassType();
 401             if (pseudoClassType != CSSSelector::PseudoClassHover && pseudoClassType != CSSSelector::PseudoClassActive)
 402                 return true;
 403             break;
 404         }
 405         case CSSSelector::Id:
 406         case CSSSelector::Class:
 407         case CSSSelector::Exact:
 408         case CSSSelector::Set:
 409         case CSSSelector::List:
 410         case CSSSelector::Hyphen:
 411         case CSSSelector::Contain:
 412         case CSSSelector::Begin:
 413         case CSSSelector::End:
 414         case CSSSelector::PagePseudoClass:
 415         case CSSSelector::PseudoElement:
 416             return true;
 417         case CSSSelector::Unknown:
 418             ASSERT_NOT_REACHED();
 419             break;
 420         }
 421
 422         CSSSelector::Relation relation = selector->relation();
 423         if (relation == CSSSelector::ShadowDescendant)
 424             return true;
 425
 426         if (relation != CSSSelector::SubSelector)
 427             return false;
 428     }
 429     return false;
 430 }
 431
 432 bool SelectorChecker::checkOne(const SelectorCheckingContext& context) const
 433 {
 434     Element* const & element = context.element;
 435     const CSSSelector* const & selector = context.selector;
 436     ASSERT(element);
 437     ASSERT(selector);
 438
 439     if (selector->m_match == CSSSelector::Tag)
 440         return SelectorChecker::tagMatches(element, selector->tagQName());
 441
 442     if (selector->m_match == CSSSelector::Class)
 443         return element->hasClass() && element->classNames().contains(selector->value());
 444
 445     if (selector->m_match == CSSSelector::Id)
 446         return element->hasID() && element->idForStyleResolution() == selector->value();
 447
 448     if (selector->isAttributeSelector()) {
 449         if (!element->hasAttributes())
 450             return false;
 451
 452         const QualifiedName& attr = selector->attribute();
 453         bool caseSensitive = !(m_documentIsHTML && element->isHTMLElement()) || HTMLDocument::isCaseSensitiveAttribute(attr);
 454
 455         if (!anyAttributeMatches(element, selector, attr, caseSensitive))
 456             return false;
 457     }
 458
 459     if (selector->m_match == CSSSelector::PseudoClass) {
 460         // Handle :not up front.
 461         if (selector->pseudoClassType() == CSSSelector::PseudoClassNot) {
 462             const CSSSelectorList* selectorList = selector->selectorList();
 463
 464             // FIXME: We probably should fix the parser and make it never produce :not rules with missing selector list.
 465             if (!selectorList)
 466                 return false;
 467
 468             SelectorCheckingContext subContext(context);
 469             subContext.inFunctionalPseudoClass = true;
 470             subContext.firstSelectorOfTheFragment = selectorList->first();
 471             for (subContext.selector = selectorList->first(); subContext.selector; subContext.selector = subContext.selector->tagHistory()) {
 472                 if (subContext.selector->m_match == CSSSelector::PseudoClass) {
 473                     // :not cannot nest. I don't really know why this is a
 474                     // restriction in CSS3, but it is, so let's honor it.
 475                     // the parser enforces that this never occurs
 476                     ASSERT(subContext.selector->pseudoClassType() != CSSSelector::PseudoClassNot);
 477                     // We select between :visited and :link when applying. We don't know which one applied (or not) yet.
 478                     if (subContext.selector->pseudoClassType() == CSSSelector::PseudoClassVisited || (subContext.selector->pseudoClassType() == CSSSelector::PseudoClassLink && subContext.visitedMatchType == VisitedMatchEnabled))
 479                         return true;
 480                 }
 481                 if (!checkOne(subContext))
 482                     return true;
 483             }
 484         } else if (context.hasScrollbarPseudo) {
 485             // CSS scrollbars match a specific subset of pseudo classes, and they have specialized rules for each
 486             // (since there are no elements involved).
 487             return checkScrollbarPseudoClass(context, &element->document(), selector);
 488         } else if (context.hasSelectionPseudo) {
 489             if (selector->pseudoClassType() == CSSSelector::PseudoClassWindowInactive)
 490                 return !element->document().page()->focusController().isActive();
 491         }
 492
 493         // Normal element pseudo class checking.
 494         switch (selector->pseudoClassType()) {
 495             // Pseudo classes:
 496         case CSSSelector::PseudoClassNot:
 497             break; // Already handled up above.
 498         case CSSSelector::PseudoClassEmpty:
 499             {
 500                 bool result = true;
 501                 for (Node* n = element->firstChild(); n; n = n->nextSibling()) {
 502                     if (n->isElementNode()) {
 503                         result = false;
 504                         break;
 505                     }
 506                     if (n->isTextNode()) {
 507                         Text* textNode = toText(n);
 508                         if (!textNode->data().isEmpty()) {
 509                             result = false;
 510                             break;
 511                         }
 512                     }
 513                 }
 514                 if (m_mode == ResolvingStyle) {
 515                     element->setStyleAffectedByEmpty();
 516                     if (context.elementStyle)
 517                         context.elementStyle->setEmptyState(result);
 518                     else if (element->renderStyle() && (element->document().styleSheetCollection().usesSiblingRules() || element->renderStyle()->unique()))
 519                         element->renderStyle()->setEmptyState(result);
 520                 }
 521                 return result;
 522             }
 523         case CSSSelector::PseudoClassFirstChild:
 524             // first-child matches the first child that is an element
 525             if (Element* parentElement = element->parentElement()) {
 526                 bool result = isFirstChildElement(element);
 527                 if (m_mode == ResolvingStyle) {
 528                     RenderStyle* childStyle = context.elementStyle ? context.elementStyle : element->renderStyle();
 529                     parentElement->setChildrenAffectedByFirstChildRules();
 530                     if (result && childStyle)
 531                         childStyle->setFirstChildState();
 532                 }
 533                 return result;
 534             }
 535             break;
 536         case CSSSelector::PseudoClassFirstOfType:
 537             // first-of-type matches the first element of its type
 538             if (Element* parentElement = element->parentElement()) {
 539                 bool result = isFirstOfType(element, element->tagQName());
 540                 if (m_mode == ResolvingStyle)
 541                     parentElement->setChildrenAffectedByForwardPositionalRules();
 542                 return result;
 543             }
 544             break;
 545         case CSSSelector::PseudoClassLastChild:
 546             // last-child matches the last child that is an element
 547             if (Element* parentElement = element->parentElement()) {
 548                 bool result = parentElement->isFinishedParsingChildren() && isLastChildElement(element);
 549                 if (m_mode == ResolvingStyle) {
 550                     RenderStyle* childStyle = context.elementStyle ? context.elementStyle : element->renderStyle();
 551                     parentElement->setChildrenAffectedByLastChildRules();
 552                     if (result && childStyle)
 553                         childStyle->setLastChildState();
 554                 }
 555                 return result;
 556             }
 557             break;
 558         case CSSSelector::PseudoClassLastOfType:
 559             // last-of-type matches the last element of its type
 560             if (Element* parentElement = element->parentElement()) {
 561                 if (m_mode == ResolvingStyle)
 562                     parentElement->setChildrenAffectedByBackwardPositionalRules();
 563                 if (!parentElement->isFinishedParsingChildren())
 564                     return false;
 565                 return isLastOfType(element, element->tagQName());
 566             }
 567             break;
 568         case CSSSelector::PseudoClassOnlyChild:
 569             if (Element* parentElement = element->parentElement()) {
 570                 bool firstChild = isFirstChildElement(element);
 571                 bool onlyChild = firstChild && parentElement->isFinishedParsingChildren() && isLastChildElement(element);
 572                 if (m_mode == ResolvingStyle) {
 573                     RenderStyle* childStyle = context.elementStyle ? context.elementStyle : element->renderStyle();
 574                     parentElement->setChildrenAffectedByFirstChildRules();
 575                     parentElement->setChildrenAffectedByLastChildRules();
 576                     if (firstChild && childStyle)
 577                         childStyle->setFirstChildState();
 578                     if (onlyChild && childStyle)
 579                         childStyle->setLastChildState();
 580                 }
 581                 return onlyChild;
 582             }
 583             break;
 584         case CSSSelector::PseudoClassOnlyOfType:
 585             // FIXME: This selector is very slow.
 586             if (Element* parentElement = element->parentElement()) {
 587                 if (m_mode == ResolvingStyle) {
 588                     parentElement->setChildrenAffectedByForwardPositionalRules();
 589                     parentElement->setChildrenAffectedByBackwardPositionalRules();
 590                 }
 591                 if (!parentElement->isFinishedParsingChildren())
 592                     return false;
 593                 return isFirstOfType(element, element->tagQName()) && isLastOfType(element, element->tagQName());
 594             }
 595             break;
 596         case CSSSelector::PseudoClassNthChild:
 597             if (!selector->parseNth())
 598                 break;
 599             if (Element* parentElement = element->parentElement()) {
 600                 int count = 1 + countElementsBefore(element);
 601                 if (m_mode == ResolvingStyle) {
 602                     RenderStyle* childStyle = context.elementStyle ? context.elementStyle : element->renderStyle();
 603                     element->setChildIndex(count);
 604                     if (childStyle)
 605                         childStyle->setUnique();
 606                     parentElement->setChildrenAffectedByForwardPositionalRules();
 607                 }
 608
 609                 if (selector->matchNth(count))
 610                     return true;
 611             }
 612             break;
 613         case CSSSelector::PseudoClassNthOfType:
 614             if (!selector->parseNth())
 615                 break;
 616             if (Element* parentElement = element->parentElement()) {
 617                 int count = 1 + countElementsOfTypeBefore(element, element->tagQName());
 618                 if (m_mode == ResolvingStyle)
 619                     parentElement->setChildrenAffectedByForwardPositionalRules();
 620
 621                 if (selector->matchNth(count))
 622                     return true;
 623             }
 624             break;
 625         case CSSSelector::PseudoClassNthLastChild:
 626             if (!selector->parseNth())
 627                 break;
 628             if (Element* parentElement = element->parentElement()) {
 629                 if (m_mode == ResolvingStyle)
 630                     parentElement->setChildrenAffectedByBackwardPositionalRules();
 631                 if (!parentElement->isFinishedParsingChildren())
 632                     return false;
 633                 int count = 1 + countElementsAfter(element);
 634                 if (selector->matchNth(count))
 635                     return true;
 636             }
 637             break;
 638         case CSSSelector::PseudoClassNthLastOfType:
 639             if (!selector->parseNth())
 640                 break;
 641             if (Element* parentElement = element->parentElement()) {
 642                 if (m_mode == ResolvingStyle)
 643                     parentElement->setChildrenAffectedByBackwardPositionalRules();
 644                 if (!parentElement->isFinishedParsingChildren())
 645                     return false;
 646
 647                 int count = 1 + countElementsOfTypeAfter(element, element->tagQName());
 648                 if (selector->matchNth(count))
 649                     return true;
 650             }
 651             break;
 652         case CSSSelector::PseudoClassTarget:
 653             if (element == element->document().cssTarget())
 654                 return true;
 655             break;
 656         case CSSSelector::PseudoClassAny:
 657             {
 658                 SelectorCheckingContext subContext(context);
 659                 subContext.inFunctionalPseudoClass = true;
 660                 PseudoId ignoreDynamicPseudo = NOPSEUDO;
 661                 for (subContext.selector = selector->selectorList()->first(); subContext.selector; subContext.selector = CSSSelectorList::next(subContext.selector)) {
 662                     subContext.firstSelectorOfTheFragment = subContext.selector;
 663                     if (matchRecursively(subContext, ignoreDynamicPseudo) == SelectorMatches)
 664                         return true;
 665                 }
 666             }
 667             break;
 668         case CSSSelector::PseudoClassAutofill:
 669             return isAutofilled(element);
 670         case CSSSelector::PseudoClassAnyLink:
 671         case CSSSelector::PseudoClassLink:
 672             // :visited and :link matches are separated later when applying the style. Here both classes match all links...
 673             return element->isLink();
 674         case CSSSelector::PseudoClassVisited:
 675             // ...except if :visited matching is disabled for ancestor/sibling matching.
 676             return element->isLink() && context.visitedMatchType == VisitedMatchEnabled;
 677         case CSSSelector::PseudoClassDrag:
 678             if (m_mode == ResolvingStyle) {
 679                 if (context.elementStyle)
 680                     context.elementStyle->setAffectedByDrag();
 681                 else
 682                     element->setChildrenAffectedByDrag();
 683             }
 684             if (element->renderer() && element->renderer()->isDragging())
 685                 return true;
 686             break;
 687         case CSSSelector::PseudoClassFocus:
 688             return matchesFocusPseudoClass(element);
 689         case CSSSelector::PseudoClassHover:
 690             if (m_strictParsing || element->isLink() || canMatchHoverOrActiveInQuirksMode(context)) {
 691                 if (m_mode == ResolvingStyle) {
 692                     if (context.elementStyle)
 693                         context.elementStyle->setAffectedByHover();
 694                     else
 695                         element->setChildrenAffectedByHover();
 696                 }
 697                 if (element->hovered() || InspectorInstrumentation::forcePseudoState(element, CSSSelector::PseudoClassHover))
 698                     return true;
 699             }
 700             break;
 701         case CSSSelector::PseudoClassActive:
 702             if (m_strictParsing || element->isLink() || canMatchHoverOrActiveInQuirksMode(context)) {
 703                 if (m_mode == ResolvingStyle) {
 704                     if (context.elementStyle)
 705                         context.elementStyle->setAffectedByActive();
 706                     else
 707                         element->setChildrenAffectedByActive();
 708                 }
 709                 if (element->active() || InspectorInstrumentation::forcePseudoState(element, CSSSelector::PseudoClassActive))
 710                     return true;
 711             }
 712             break;
 713         case CSSSelector::PseudoClassEnabled:
 714             return isEnabled(element);
 715         case CSSSelector::PseudoClassFullPageMedia:
 716             return element->document().isMediaDocument();
 717         case CSSSelector::PseudoClassDefault:
 718             return isDefaultButtonForForm(element);
 719         case CSSSelector::PseudoClassDisabled:
 720             return isDisabled(element);
 721         case CSSSelector::PseudoClassReadOnly:
 722             return matchesReadOnlyPseudoClass(element);
 723         case CSSSelector::PseudoClassReadWrite:
 724             return matchesReadWritePseudoClass(element);
 725         case CSSSelector::PseudoClassOptional:
 726             return isOptionalFormControl(element);
 727         case CSSSelector::PseudoClassRequired:
 728             return isRequiredFormControl(element);
 729         case CSSSelector::PseudoClassValid:
 730             return isValid(element);
 731         case CSSSelector::PseudoClassInvalid:
 732             return isInvalid(element);
 733         case CSSSelector::PseudoClassChecked:
 734             return isChecked(element);
 735         case CSSSelector::PseudoClassIndeterminate:
 736             return shouldAppearIndeterminate(element);
 737         case CSSSelector::PseudoClassRoot:
 738             if (element == element->document().documentElement())
 739                 return true;
 740             break;
 741         case CSSSelector::PseudoClassLang:
 742             {
 743                 const AtomicString& argument = selector->argument();
 744                 if (argument.isNull())
 745                     return false;
 746                 return matchesLangPseudoClass(element, argument.impl());
 747             }
 748 #if ENABLE(FULLSCREEN_API)
 749         case CSSSelector::PseudoClassFullScreen:
 750             return matchesFullScreenPseudoClass(element);
 751         case CSSSelector::PseudoClassAnimatingFullScreenTransition:
 752             if (element != element->document().webkitCurrentFullScreenElement())
 753                 return false;
 754             return element->document().isAnimatingFullScreen();
 755         case CSSSelector::PseudoClassFullScreenAncestor:
 756             return element->containsFullScreenElement();
 757         case CSSSelector::PseudoClassFullScreenDocument:
 758             // While a Document is in the fullscreen state, the 'full-screen-document' pseudoclass applies
 759             // to all elements of that Document.
 760             if (!element->document().webkitIsFullScreen())
 761                 return false;
 762             return true;
 763 #endif
 764         case CSSSelector::PseudoClassInRange:
 765             return isInRange(element);
 766         case CSSSelector::PseudoClassOutOfRange:
 767             return isOutOfRange(element);
 768 #if ENABLE(VIDEO_TRACK)
 769         case CSSSelector::PseudoClassFuture:
 770             return matchesFutureCuePseudoClass(element);
 771         case CSSSelector::PseudoClassPast:
 772             return matchesPastCuePseudoClass(element);
 773 #endif
 774
 775         case CSSSelector::PseudoClassScope:
 776             {
 777                 const Node* contextualReferenceNode = !context.scope ? element->document().documentElement() : context.scope;
 778                 if (element == contextualReferenceNode)
 779                     return true;
 780                 break;
 781             }
 782
 783         case CSSSelector::PseudoClassHorizontal:
 784         case CSSSelector::PseudoClassVertical:
 785         case CSSSelector::PseudoClassDecrement:
 786         case CSSSelector::PseudoClassIncrement:
 787         case CSSSelector::PseudoClassStart:
 788         case CSSSelector::PseudoClassEnd:
 789         case CSSSelector::PseudoClassDoubleButton:
 790         case CSSSelector::PseudoClassSingleButton:
 791         case CSSSelector::PseudoClassNoButton:
 792         case CSSSelector::PseudoClassCornerPresent:
 793             return false;
 794
 795         case CSSSelector::PseudoClassUnknown:
 796         default:
 797             ASSERT_NOT_REACHED();
 798             break;
 799         }
 800         return false;
 801     }
 802 #if ENABLE(VIDEO_TRACK)
 803     else if (selector->m_match == CSSSelector::PseudoElement && selector->pseudoElementType() == CSSSelector::PseudoElementCue) {
 804         SelectorCheckingContext subContext(context);
 805
 806         PseudoId ignoreDynamicPseudo = NOPSEUDO;
 807         const CSSSelector* const & selector = context.selector;
 808         for (subContext.selector = selector->selectorList()->first(); subContext.selector; subContext.selector = CSSSelectorList::next(subContext.selector)) {
 809             subContext.firstSelectorOfTheFragment = subContext.selector;
 810             subContext.inFunctionalPseudoClass = true;
 811             if (matchRecursively(subContext, ignoreDynamicPseudo) == SelectorMatches)
 812                 return true;
 813         }
 814         return false;
 815     }
 816 #endif
 817     // ### add the rest of the checks...
 818     return true;
 819 }
 820
 821 bool SelectorChecker::checkScrollbarPseudoClass(const SelectorCheckingContext& context, Document* document, const CSSSelector* selector) const
 822 {
 823     ASSERT(selector->m_match == CSSSelector::PseudoClass);
 824
 825     RenderScrollbar* scrollbar = context.scrollbar;
 826     ScrollbarPart part = context.scrollbarPart;
 827
 828     // FIXME: This is a temporary hack for resizers and scrollbar corners. Eventually :window-inactive should become a real
 829     // pseudo class and just apply to everything.
 830     if (selector->pseudoClassType() == CSSSelector::PseudoClassWindowInactive)
 831         return !document->page()->focusController().isActive();
 832
 833     if (!scrollbar)
 834         return false;
 835
 836     switch (selector->pseudoClassType()) {
 837     case CSSSelector::PseudoClassEnabled:
 838         return scrollbar->enabled();
 839     case CSSSelector::PseudoClassDisabled:
 840         return !scrollbar->enabled();
 841     case CSSSelector::PseudoClassHover:
 842         {
 843             ScrollbarPart hoveredPart = scrollbar->hoveredPart();
 844             if (part == ScrollbarBGPart)
 845                 return hoveredPart != NoPart;
 846             if (part == TrackBGPart)
 847                 return hoveredPart == BackTrackPart || hoveredPart == ForwardTrackPart || hoveredPart == ThumbPart;
 848             return part == hoveredPart;
 849         }
 850     case CSSSelector::PseudoClassActive:
 851         {
 852             ScrollbarPart pressedPart = scrollbar->pressedPart();
 853             if (part == ScrollbarBGPart)
 854                 return pressedPart != NoPart;
 855             if (part == TrackBGPart)
 856                 return pressedPart == BackTrackPart || pressedPart == ForwardTrackPart || pressedPart == ThumbPart;
 857             return part == pressedPart;
 858         }
 859     case CSSSelector::PseudoClassHorizontal:
 860         return scrollbar->orientation() == HorizontalScrollbar;
 861     case CSSSelector::PseudoClassVertical:
 862         return scrollbar->orientation() == VerticalScrollbar;
 863     case CSSSelector::PseudoClassDecrement:
 864         return part == BackButtonStartPart || part == BackButtonEndPart || part == BackTrackPart;
 865     case CSSSelector::PseudoClassIncrement:
 866         return part == ForwardButtonStartPart || part == ForwardButtonEndPart || part == ForwardTrackPart;
 867     case CSSSelector::PseudoClassStart:
 868         return part == BackButtonStartPart || part == ForwardButtonStartPart || part == BackTrackPart;
 869     case CSSSelector::PseudoClassEnd:
 870         return part == BackButtonEndPart || part == ForwardButtonEndPart || part == ForwardTrackPart;
 871     case CSSSelector::PseudoClassDoubleButton:
 872         {
 873             ScrollbarButtonsPlacement buttonsPlacement = scrollbar->theme()->buttonsPlacement();
 874             if (part == BackButtonStartPart || part == ForwardButtonStartPart || part == BackTrackPart)
 875                 return buttonsPlacement == ScrollbarButtonsDoubleStart || buttonsPlacement == ScrollbarButtonsDoubleBoth;
 876             if (part == BackButtonEndPart || part == ForwardButtonEndPart || part == ForwardTrackPart)
 877                 return buttonsPlacement == ScrollbarButtonsDoubleEnd || buttonsPlacement == ScrollbarButtonsDoubleBoth;
 878             return false;
 879         }
 880     case CSSSelector::PseudoClassSingleButton:
 881         {
 882             ScrollbarButtonsPlacement buttonsPlacement = scrollbar->theme()->buttonsPlacement();
 883             if (part == BackButtonStartPart || part == ForwardButtonEndPart || part == BackTrackPart || part == ForwardTrackPart)
 884                 return buttonsPlacement == ScrollbarButtonsSingle;
 885             return false;
 886         }
 887     case CSSSelector::PseudoClassNoButton:
 888         {
 889             ScrollbarButtonsPlacement buttonsPlacement = scrollbar->theme()->buttonsPlacement();
 890             if (part == BackTrackPart)
 891                 return buttonsPlacement == ScrollbarButtonsNone || buttonsPlacement == ScrollbarButtonsDoubleEnd;
 892             if (part == ForwardTrackPart)
 893                 return buttonsPlacement == ScrollbarButtonsNone || buttonsPlacement == ScrollbarButtonsDoubleStart;
 894             return false;
 895         }
 896     case CSSSelector::PseudoClassCornerPresent:
 897         return scrollbar->scrollableArea()->isScrollCornerVisible();
 898     default:
 899         return false;
 900     }
 901 }
 902
 903 unsigned SelectorChecker::determineLinkMatchType(const CSSSelector* selector)
 904 {
 905     unsigned linkMatchType = MatchAll;
 906
 907     // Statically determine if this selector will match a link in visited, unvisited or any state, or never.
 908     // :visited never matches other elements than the innermost link element.
 909     for (; selector; selector = selector->tagHistory()) {
 910         if (selector->m_match == CSSSelector::PseudoClass) {
 911             switch (selector->pseudoClassType()) {
 912             case CSSSelector::PseudoClassNot:
 913                 {
 914                     // :not(:visited) is equivalent to :link. Parser enforces that :not can't nest.
 915                     const CSSSelectorList* selectorList = selector->selectorList();
 916                     if (!selectorList)
 917                         break;
 918
 919                     for (const CSSSelector* subSelector = selectorList->first(); subSelector; subSelector = subSelector->tagHistory()) {
 920                         if (subSelector->m_match == CSSSelector::PseudoClass) {
 921                             CSSSelector::PseudoClassType subType = subSelector->pseudoClassType();
 922                             if (subType == CSSSelector::PseudoClassVisited)
 923                                 linkMatchType &= ~SelectorChecker::MatchVisited;
 924                             else if (subType == CSSSelector::PseudoClassLink)
 925                                 linkMatchType &= ~SelectorChecker::MatchLink;
 926                         }
 927                     }
 928                 }
 929                 break;
 930             case CSSSelector::PseudoClassLink:
 931                 linkMatchType &= ~SelectorChecker::MatchVisited;
 932                 break;
 933             case CSSSelector::PseudoClassVisited:
 934                 linkMatchType &= ~SelectorChecker::MatchLink;
 935                 break;
 936             default:
 937                 // We don't support :link and :visited inside :-webkit-any.
 938                 break;
 939             }
 940         }
 941         CSSSelector::Relation relation = selector->relation();
 942         if (relation == CSSSelector::SubSelector)
 943             continue;
 944         if (relation != CSSSelector::Descendant && relation != CSSSelector::Child)
 945             return linkMatchType;
 946         if (linkMatchType != MatchAll)
 947             return linkMatchType;
 948     }
 949     return linkMatchType;
 950 }
 951
 952 static bool isFrameFocused(const Element* element)
 953 {
 954     return element->document().frame() && element->document().frame()->selection().isFocusedAndActive();
 955 }
 956
 957 bool SelectorChecker::matchesFocusPseudoClass(const Element* element)
 958 {
 959     if (InspectorInstrumentation::forcePseudoState(const_cast<Element*>(element), CSSSelector::PseudoClassFocus))
 960         return true;
 961     return element->focused() && isFrameFocused(element);
 962 }
 963
 964 }