src/third_party/WebKit/Source/core/dom/SelectorQuery.cpp

   1 /*
   2  * Copyright (C) 2011, 2013 Apple Inc. All rights reserved.
   3  * Copyright (C) 2014 Samsung Electronics. All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1.  Redistributions of source code must retain the above copyright
  10  *     notice, this list of conditions and the following disclaimer.
  11  * 2.  Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  16  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  18  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  19  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "config.h"
  28 #include "core/dom/SelectorQuery.h"
  29
  30 #include "bindings/core/v8/ExceptionState.h"
  31 #include "core/css/SelectorChecker.h"
  32 #include "core/css/SiblingTraversalStrategies.h"
  33 #include "core/css/parser/CSSParser.h"
  34 #include "core/dom/Document.h"
  35 #include "core/dom/ElementTraversal.h"
  36 #include "core/dom/Node.h"
  37 #include "core/dom/StaticNodeList.h"
  38 #include "core/dom/shadow/ElementShadow.h"
  39 #include "core/dom/shadow/ShadowRoot.h"
  40
  41 namespace blink {
  42
  43 struct SingleElementSelectorQueryTrait {
  44     typedef Element* OutputType;
  45     static const bool shouldOnlyMatchFirstElement = true;
  46     ALWAYS_INLINE static void appendElement(OutputType& output, Element& element)
  47     {
  48         ASSERT(!output);
  49         output = &element;
  50     }
  51 };
  52
  53 struct AllElementsSelectorQueryTrait {
  54     typedef WillBeHeapVector<RefPtrWillBeMember<Element> > OutputType;
  55     static const bool shouldOnlyMatchFirstElement = false;
  56     ALWAYS_INLINE static void appendElement(OutputType& output, Element& element)
  57     {
  58         output.append(&element);
  59     }
  60 };
  61
  62 enum ClassElementListBehavior { AllElements, OnlyRoots };
  63
  64 template <ClassElementListBehavior onlyRoots>
  65 class ClassElementList {
  66     STACK_ALLOCATED();
  67 public:
  68     ClassElementList(ContainerNode& rootNode, const AtomicString& className)
  69         : m_className(className)
  70         , m_rootNode(&rootNode)
  71         , m_currentElement(nextInternal(ElementTraversal::firstWithin(rootNode))) { }
  72
  73     bool isEmpty() const { return !m_currentElement; }
  74
  75     Element* next()
  76     {
  77         Element* current = m_currentElement;
  78         ASSERT(current);
  79         if (onlyRoots)
  80             m_currentElement = nextInternal(ElementTraversal::nextSkippingChildren(*m_currentElement, m_rootNode));
  81         else
  82             m_currentElement = nextInternal(ElementTraversal::next(*m_currentElement, m_rootNode));
  83         return current;
  84     }
  85
  86 private:
  87     Element* nextInternal(Element* element)
  88     {
  89         for (; element; element = ElementTraversal::next(*element, m_rootNode)) {
  90             if (element->hasClass() && element->classNames().contains(m_className))
  91                 return element;
  92         }
  93         return 0;
  94     }
  95
  96     const AtomicString& m_className;
  97     RawPtrWillBeMember<ContainerNode> m_rootNode;
  98     RawPtrWillBeMember<Element> m_currentElement;
  99 };
 100
 101 void SelectorDataList::initialize(const CSSSelectorList& selectorList)
 102 {
 103     ASSERT(m_selectors.isEmpty());
 104
 105     unsigned selectorCount = 0;
 106     for (const CSSSelector* selector = selectorList.first(); selector; selector = CSSSelectorList::next(*selector))
 107         selectorCount++;
 108
 109     m_crossesTreeBoundary = false;
 110     m_selectors.reserveInitialCapacity(selectorCount);
 111     unsigned index = 0;
 112     for (const CSSSelector* selector = selectorList.first(); selector; selector = CSSSelectorList::next(*selector), ++index) {
 113         m_selectors.uncheckedAppend(selector);
 114         m_crossesTreeBoundary |= selectorList.selectorCrossesTreeScopes(index);
 115     }
 116 }
 117
 118 inline bool SelectorDataList::selectorMatches(const CSSSelector& selector, Element& element, const ContainerNode& rootNode) const
 119 {
 120     SelectorChecker selectorChecker(element.document(), SelectorChecker::QueryingRules);
 121     SelectorChecker::SelectorCheckingContext selectorCheckingContext(selector, &element, SelectorChecker::VisitedMatchDisabled);
 122     selectorCheckingContext.scope = !rootNode.isDocumentNode() ? &rootNode : 0;
 123     if (selectorCheckingContext.scope)
 124         selectorCheckingContext.contextFlags = SelectorChecker::ScopeContainsLastMatchedElement;
 125     return selectorChecker.match(selectorCheckingContext, DOMSiblingTraversalStrategy()) == SelectorChecker::SelectorMatches;
 126 }
 127
 128 bool SelectorDataList::matches(Element& targetElement) const
 129 {
 130     unsigned selectorCount = m_selectors.size();
 131     for (unsigned i = 0; i < selectorCount; ++i) {
 132         if (selectorMatches(*m_selectors[i], targetElement, targetElement))
 133             return true;
 134     }
 135
 136     return false;
 137 }
 138
 139 PassRefPtrWillBeRawPtr<StaticElementList> SelectorDataList::queryAll(ContainerNode& rootNode) const
 140 {
 141     WillBeHeapVector<RefPtrWillBeMember<Element> > result;
 142     execute<AllElementsSelectorQueryTrait>(rootNode, result);
 143     return StaticElementList::adopt(result);
 144 }
 145
 146 PassRefPtrWillBeRawPtr<Element> SelectorDataList::queryFirst(ContainerNode& rootNode) const
 147 {
 148     Element* matchedElement = 0;
 149     execute<SingleElementSelectorQueryTrait>(rootNode, matchedElement);
 150     return matchedElement;
 151 }
 152
 153 template <typename SelectorQueryTrait>
 154 void SelectorDataList::collectElementsByClassName(ContainerNode& rootNode, const AtomicString& className,  typename SelectorQueryTrait::OutputType& output) const
 155 {
 156     for (Element* element = ElementTraversal::firstWithin(rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
 157         if (element->hasClass() && element->classNames().contains(className)) {
 158             SelectorQueryTrait::appendElement(output, *element);
 159             if (SelectorQueryTrait::shouldOnlyMatchFirstElement)
 160                 return;
 161         }
 162     }
 163 }
 164
 165 template <typename SelectorQueryTrait>
 166 void SelectorDataList::collectElementsByTagName(ContainerNode& rootNode, const QualifiedName& tagName,  typename SelectorQueryTrait::OutputType& output) const
 167 {
 168     for (Element* element = ElementTraversal::firstWithin(rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
 169         if (SelectorChecker::tagMatches(*element, tagName)) {
 170             SelectorQueryTrait::appendElement(output, *element);
 171             if (SelectorQueryTrait::shouldOnlyMatchFirstElement)
 172                 return;
 173         }
 174     }
 175 }
 176
 177 inline bool SelectorDataList::canUseFastQuery(const ContainerNode& rootNode) const
 178 {
 179     return m_selectors.size() == 1 && !m_crossesTreeBoundary && rootNode.inDocument() && !rootNode.document().inQuirksMode();
 180 }
 181
 182 inline bool ancestorHasClassName(ContainerNode& rootNode, const AtomicString& className)
 183 {
 184     if (!rootNode.isElementNode())
 185         return false;
 186
 187     for (Element* element = &toElement(rootNode); element; element = element->parentElement()) {
 188         if (element->hasClass() && element->classNames().contains(className))
 189             return true;
 190     }
 191     return false;
 192 }
 193
 194
 195 // If returns true, traversalRoots has the elements that may match the selector query.
 196 //
 197 // If returns false, traversalRoots has the rootNode parameter or descendants of rootNode representing
 198 // the subtree for which we can limit the querySelector traversal.
 199 //
 200 // The travseralRoots may be empty, regardless of the returned bool value, if this method finds that the selectors won't
 201 // match any element.
 202 template <typename SelectorQueryTrait>
 203 void SelectorDataList::findTraverseRootsAndExecute(ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 204 {
 205     // We need to return the matches in document order. To use id lookup while there is possiblity of multiple matches
 206     // we would need to sort the results. For now, just traverse the document in that case.
 207     ASSERT(m_selectors.size() == 1);
 208
 209     bool isRightmostSelector = true;
 210     bool startFromParent = false;
 211
 212     for (const CSSSelector* selector = m_selectors[0]; selector; selector = selector->tagHistory()) {
 213         if (selector->match() == CSSSelector::Id && !rootNode.document().containsMultipleElementsWithId(selector->value())) {
 214             Element* element = rootNode.treeScope().getElementById(selector->value());
 215             ContainerNode* adjustedNode = &rootNode;
 216             if (element && (isTreeScopeRoot(rootNode) || element->isDescendantOf(&rootNode)))
 217                 adjustedNode = element;
 218             else if (!element || isRightmostSelector)
 219                 adjustedNode = 0;
 220             if (isRightmostSelector) {
 221                 executeForTraverseRoot<SelectorQueryTrait>(*m_selectors[0], adjustedNode, MatchesTraverseRoots, rootNode, output);
 222                 return;
 223             }
 224
 225             if (startFromParent && adjustedNode)
 226                 adjustedNode = adjustedNode->parentNode();
 227
 228             executeForTraverseRoot<SelectorQueryTrait>(*m_selectors[0], adjustedNode, DoesNotMatchTraverseRoots, rootNode, output);
 229             return;
 230         }
 231
 232         // If we have both CSSSelector::Id and CSSSelector::Class at the same time, we should use Id
 233         // to find traverse root.
 234         if (!SelectorQueryTrait::shouldOnlyMatchFirstElement && !startFromParent && selector->match() == CSSSelector::Class) {
 235             if (isRightmostSelector) {
 236                 ClassElementList<AllElements> traverseRoots(rootNode, selector->value());
 237                 executeForTraverseRoots<SelectorQueryTrait>(*m_selectors[0], traverseRoots, MatchesTraverseRoots, rootNode, output);
 238                 return;
 239             }
 240             // Since there exists some ancestor element which has the class name, we need to see all children of rootNode.
 241             if (ancestorHasClassName(rootNode, selector->value())) {
 242                 executeForTraverseRoot<SelectorQueryTrait>(*m_selectors[0], &rootNode, DoesNotMatchTraverseRoots, rootNode, output);
 243                 return;
 244             }
 245
 246             ClassElementList<OnlyRoots> traverseRoots(rootNode, selector->value());
 247             executeForTraverseRoots<SelectorQueryTrait>(*m_selectors[0], traverseRoots, DoesNotMatchTraverseRoots, rootNode, output);
 248             return;
 249         }
 250
 251         if (selector->relation() == CSSSelector::SubSelector)
 252             continue;
 253         isRightmostSelector = false;
 254         if (selector->relation() == CSSSelector::DirectAdjacent || selector->relation() == CSSSelector::IndirectAdjacent)
 255             startFromParent = true;
 256         else
 257             startFromParent = false;
 258     }
 259
 260     executeForTraverseRoot<SelectorQueryTrait>(*m_selectors[0], &rootNode, DoesNotMatchTraverseRoots, rootNode, output);
 261 }
 262
 263 template <typename SelectorQueryTrait>
 264 void SelectorDataList::executeForTraverseRoot(const CSSSelector& selector, ContainerNode* traverseRoot, MatchTraverseRootState matchTraverseRoot, ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 265 {
 266     if (!traverseRoot)
 267         return;
 268
 269     if (matchTraverseRoot) {
 270         if (selectorMatches(selector, toElement(*traverseRoot), rootNode))
 271             SelectorQueryTrait::appendElement(output, toElement(*traverseRoot));
 272         return;
 273     }
 274
 275     for (Element* element = ElementTraversal::firstWithin(*traverseRoot); element; element = ElementTraversal::next(*element, traverseRoot)) {
 276         if (selectorMatches(selector, *element, rootNode)) {
 277             SelectorQueryTrait::appendElement(output, *element);
 278             if (SelectorQueryTrait::shouldOnlyMatchFirstElement)
 279                 return;
 280         }
 281     }
 282 }
 283
 284 template <typename SelectorQueryTrait, typename SimpleElementListType>
 285 void SelectorDataList::executeForTraverseRoots(const CSSSelector& selector, SimpleElementListType& traverseRoots, MatchTraverseRootState matchTraverseRoots, ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 286 {
 287     if (traverseRoots.isEmpty())
 288         return;
 289
 290     if (matchTraverseRoots) {
 291         while (!traverseRoots.isEmpty()) {
 292             Element& element = *traverseRoots.next();
 293             if (selectorMatches(selector, element, rootNode)) {
 294                 SelectorQueryTrait::appendElement(output, element);
 295                 if (SelectorQueryTrait::shouldOnlyMatchFirstElement)
 296                     return;
 297             }
 298         }
 299         return;
 300     }
 301
 302     while (!traverseRoots.isEmpty()) {
 303         Element& traverseRoot = *traverseRoots.next();
 304         for (Element* element = ElementTraversal::firstWithin(traverseRoot); element; element = ElementTraversal::next(*element, &traverseRoot)) {
 305             if (selectorMatches(selector, *element, rootNode)) {
 306                 SelectorQueryTrait::appendElement(output, *element);
 307                 if (SelectorQueryTrait::shouldOnlyMatchFirstElement)
 308                     return;
 309             }
 310         }
 311     }
 312 }
 313
 314 template <typename SelectorQueryTrait>
 315 bool SelectorDataList::selectorListMatches(ContainerNode& rootNode, Element& element, typename SelectorQueryTrait::OutputType& output) const
 316 {
 317     for (unsigned i = 0; i < m_selectors.size(); ++i) {
 318         if (selectorMatches(*m_selectors[i], element, rootNode)) {
 319             SelectorQueryTrait::appendElement(output, element);
 320             return true;
 321         }
 322     }
 323     return false;
 324 }
 325
 326 template <typename SelectorQueryTrait>
 327 void SelectorDataList::executeSlow(ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 328 {
 329     for (Element* element = ElementTraversal::firstWithin(rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
 330         if (selectorListMatches<SelectorQueryTrait>(rootNode, *element, output) && SelectorQueryTrait::shouldOnlyMatchFirstElement)
 331             return;
 332     }
 333 }
 334
 335 // FIXME: Move the following helper functions, authorShadowRootOf, firstWithinTraversingShadowTree,
 336 // nextTraversingShadowTree to the best place, e.g. NodeTraversal.
 337 static ShadowRoot* authorShadowRootOf(const ContainerNode& node)
 338 {
 339     if (!node.isElementNode() || !isShadowHost(&node))
 340         return 0;
 341
 342     ElementShadow* shadow = toElement(node).shadow();
 343     ASSERT(shadow);
 344     for (ShadowRoot* shadowRoot = shadow->oldestShadowRoot(); shadowRoot; shadowRoot = shadowRoot->youngerShadowRoot()) {
 345         if (shadowRoot->type() == ShadowRoot::AuthorShadowRoot)
 346             return shadowRoot;
 347     }
 348     return 0;
 349 }
 350
 351 static ContainerNode* firstWithinTraversingShadowTree(const ContainerNode& rootNode)
 352 {
 353     if (ShadowRoot* shadowRoot = authorShadowRootOf(rootNode))
 354         return shadowRoot;
 355     return ElementTraversal::firstWithin(rootNode);
 356 }
 357
 358 static ContainerNode* nextTraversingShadowTree(const ContainerNode& node, const ContainerNode* rootNode)
 359 {
 360     if (ShadowRoot* shadowRoot = authorShadowRootOf(node))
 361         return shadowRoot;
 362
 363     const ContainerNode* current = &node;
 364     while (current) {
 365         if (Element* next = ElementTraversal::next(*current, rootNode))
 366             return next;
 367
 368         if (!current->isInShadowTree())
 369             return 0;
 370
 371         ShadowRoot* shadowRoot = current->containingShadowRoot();
 372         if (shadowRoot == rootNode)
 373             return 0;
 374         if (ShadowRoot* youngerShadowRoot = shadowRoot->youngerShadowRoot()) {
 375             // Should not obtain any elements in user-agent shadow root.
 376             ASSERT(youngerShadowRoot->type() == ShadowRoot::AuthorShadowRoot);
 377             return youngerShadowRoot;
 378         }
 379
 380         current = shadowRoot->host();
 381     }
 382     return 0;
 383 }
 384
 385 template <typename SelectorQueryTrait>
 386 void SelectorDataList::executeSlowTraversingShadowTree(ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 387 {
 388     for (ContainerNode* node = firstWithinTraversingShadowTree(rootNode); node; node = nextTraversingShadowTree(*node, &rootNode)) {
 389         if (!node->isElementNode())
 390             continue;
 391         Element* element = toElement(node);
 392         if (selectorListMatches<SelectorQueryTrait>(rootNode, *element, output) && SelectorQueryTrait::shouldOnlyMatchFirstElement)
 393             return;
 394     }
 395 }
 396
 397 const CSSSelector* SelectorDataList::selectorForIdLookup(const CSSSelector& firstSelector) const
 398 {
 399     for (const CSSSelector* selector = &firstSelector; selector; selector = selector->tagHistory()) {
 400         if (selector->match() == CSSSelector::Id)
 401             return selector;
 402         if (selector->relation() != CSSSelector::SubSelector)
 403             break;
 404     }
 405     return 0;
 406 }
 407
 408 template <typename SelectorQueryTrait>
 409 void SelectorDataList::execute(ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 410 {
 411     if (!canUseFastQuery(rootNode)) {
 412         if (m_crossesTreeBoundary) {
 413             rootNode.document().updateDistributionForNodeIfNeeded(&rootNode);
 414             executeSlowTraversingShadowTree<SelectorQueryTrait>(rootNode, output);
 415         } else {
 416             executeSlow<SelectorQueryTrait>(rootNode, output);
 417         }
 418         return;
 419     }
 420
 421     ASSERT(m_selectors.size() == 1);
 422
 423     const CSSSelector& selector = *m_selectors[0];
 424     const CSSSelector& firstSelector = selector;
 425
 426     // Fast path for querySelector*('#id'), querySelector*('tag#id').
 427     if (const CSSSelector* idSelector = selectorForIdLookup(firstSelector)) {
 428         const AtomicString& idToMatch = idSelector->value();
 429         if (rootNode.treeScope().containsMultipleElementsWithId(idToMatch)) {
 430             const WillBeHeapVector<RawPtrWillBeMember<Element> >& elements = rootNode.treeScope().getAllElementsById(idToMatch);
 431             size_t count = elements.size();
 432             for (size_t i = 0; i < count; ++i) {
 433                 Element& element = *elements[i];
 434                 if (!(isTreeScopeRoot(rootNode) || element.isDescendantOf(&rootNode)))
 435                     continue;
 436                 if (selectorMatches(selector, element, rootNode)) {
 437                     SelectorQueryTrait::appendElement(output, element);
 438                     if (SelectorQueryTrait::shouldOnlyMatchFirstElement)
 439                         return;
 440                 }
 441             }
 442             return;
 443         }
 444         Element* element = rootNode.treeScope().getElementById(idToMatch);
 445         if (!element || !(isTreeScopeRoot(rootNode) || element->isDescendantOf(&rootNode)))
 446             return;
 447         if (selectorMatches(selector, *element, rootNode))
 448             SelectorQueryTrait::appendElement(output, *element);
 449         return;
 450     }
 451
 452     if (!firstSelector.tagHistory()) {
 453         // Fast path for querySelector*('.foo'), and querySelector*('div').
 454         switch (firstSelector.match()) {
 455         case CSSSelector::Class:
 456             collectElementsByClassName<SelectorQueryTrait>(rootNode, firstSelector.value(), output);
 457             return;
 458         case CSSSelector::Tag:
 459             collectElementsByTagName<SelectorQueryTrait>(rootNode, firstSelector.tagQName(), output);
 460             return;
 461         default:
 462             break; // If we need another fast path, add here.
 463         }
 464     }
 465
 466     findTraverseRootsAndExecute<SelectorQueryTrait>(rootNode, output);
 467 }
 468
 469 PassOwnPtr<SelectorQuery> SelectorQuery::adopt(CSSSelectorList& selectorList)
 470 {
 471     return adoptPtr(new SelectorQuery(selectorList));
 472 }
 473
 474 SelectorQuery::SelectorQuery(CSSSelectorList& selectorList)
 475 {
 476     m_selectorList.adopt(selectorList);
 477     m_selectors.initialize(m_selectorList);
 478 }
 479
 480 bool SelectorQuery::matches(Element& element) const
 481 {
 482     return m_selectors.matches(element);
 483 }
 484
 485 PassRefPtrWillBeRawPtr<StaticElementList> SelectorQuery::queryAll(ContainerNode& rootNode) const
 486 {
 487     return m_selectors.queryAll(rootNode);
 488 }
 489
 490 PassRefPtrWillBeRawPtr<Element> SelectorQuery::queryFirst(ContainerNode& rootNode) const
 491 {
 492     return m_selectors.queryFirst(rootNode);
 493 }
 494
 495 SelectorQuery* SelectorQueryCache::add(const AtomicString& selectors, const Document& document, ExceptionState& exceptionState)
 496 {
 497     HashMap<AtomicString, OwnPtr<SelectorQuery> >::iterator it = m_entries.find(selectors);
 498     if (it != m_entries.end())
 499         return it->value.get();
 500
 501     CSSParser parser(CSSParserContext(document, 0));
 502     CSSSelectorList selectorList;
 503     parser.parseSelector(selectors, selectorList);
 504
 505     if (!selectorList.first()) {
 506         exceptionState.throwDOMException(SyntaxError, "'" + selectors + "' is not a valid selector.");
 507         return 0;
 508     }
 509
 510     // throw a NamespaceError if the selector includes any namespace prefixes.
 511     if (selectorList.selectorsNeedNamespaceResolution()) {
 512         exceptionState.throwDOMException(NamespaceError, "'" + selectors + "' contains namespaces, which are not supported.");
 513         return 0;
 514     }
 515
 516     const unsigned maximumSelectorQueryCacheSize = 256;
 517     if (m_entries.size() == maximumSelectorQueryCacheSize)
 518         m_entries.remove(m_entries.begin());
 519
 520     return m_entries.add(selectors, SelectorQuery::adopt(selectorList)).storedValue->value.get();
 521 }
 522
 523 void SelectorQueryCache::invalidate()
 524 {
 525     m_entries.clear();
 526 }
 527
 528 }