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.scopeContainsLastMatchedElement = true;
 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::descendantsOf(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::descendantsOf(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::descendantsOf(*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         for (Element& element : ElementTraversal::descendantsOf(*traverseRoots.next())) {
 304             if (selectorMatches(selector, element, rootNode)) {
 305                 SelectorQueryTrait::appendElement(output, element);
 306                 if (SelectorQueryTrait::shouldOnlyMatchFirstElement)
 307                     return;
 308             }
 309         }
 310     }
 311 }
 312
 313 template <typename SelectorQueryTrait>
 314 bool SelectorDataList::selectorListMatches(ContainerNode& rootNode, Element& element, typename SelectorQueryTrait::OutputType& output) const
 315 {
 316     for (unsigned i = 0; i < m_selectors.size(); ++i) {
 317         if (selectorMatches(*m_selectors[i], element, rootNode)) {
 318             SelectorQueryTrait::appendElement(output, element);
 319             return true;
 320         }
 321     }
 322     return false;
 323 }
 324
 325 template <typename SelectorQueryTrait>
 326 void SelectorDataList::executeSlow(ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 327 {
 328     for (Element& element : ElementTraversal::descendantsOf(rootNode)) {
 329         if (selectorListMatches<SelectorQueryTrait>(rootNode, element, output) && SelectorQueryTrait::shouldOnlyMatchFirstElement)
 330             return;
 331     }
 332 }
 333
 334 // FIXME: Move the following helper functions, authorShadowRootOf, firstWithinTraversingShadowTree,
 335 // nextTraversingShadowTree to the best place, e.g. NodeTraversal.
 336 static ShadowRoot* authorShadowRootOf(const ContainerNode& node)
 337 {
 338     if (!node.isElementNode() || !isShadowHost(&node))
 339         return 0;
 340
 341     ElementShadow* shadow = toElement(node).shadow();
 342     ASSERT(shadow);
 343     for (ShadowRoot* shadowRoot = shadow->oldestShadowRoot(); shadowRoot; shadowRoot = shadowRoot->youngerShadowRoot()) {
 344         if (shadowRoot->type() == ShadowRoot::AuthorShadowRoot)
 345             return shadowRoot;
 346     }
 347     return 0;
 348 }
 349
 350 static ContainerNode* firstWithinTraversingShadowTree(const ContainerNode& rootNode)
 351 {
 352     if (ShadowRoot* shadowRoot = authorShadowRootOf(rootNode))
 353         return shadowRoot;
 354     return ElementTraversal::firstWithin(rootNode);
 355 }
 356
 357 static ContainerNode* nextTraversingShadowTree(const ContainerNode& node, const ContainerNode* rootNode)
 358 {
 359     if (ShadowRoot* shadowRoot = authorShadowRootOf(node))
 360         return shadowRoot;
 361
 362     const ContainerNode* current = &node;
 363     while (current) {
 364         if (Element* next = ElementTraversal::next(*current, rootNode))
 365             return next;
 366
 367         if (!current->isInShadowTree())
 368             return 0;
 369
 370         ShadowRoot* shadowRoot = current->containingShadowRoot();
 371         if (shadowRoot == rootNode)
 372             return 0;
 373         if (ShadowRoot* youngerShadowRoot = shadowRoot->youngerShadowRoot()) {
 374             // Should not obtain any elements in user-agent shadow root.
 375             ASSERT(youngerShadowRoot->type() == ShadowRoot::AuthorShadowRoot);
 376             return youngerShadowRoot;
 377         }
 378
 379         current = shadowRoot->host();
 380     }
 381     return 0;
 382 }
 383
 384 template <typename SelectorQueryTrait>
 385 void SelectorDataList::executeSlowTraversingShadowTree(ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 386 {
 387     for (ContainerNode* node = firstWithinTraversingShadowTree(rootNode); node; node = nextTraversingShadowTree(*node, &rootNode)) {
 388         if (!node->isElementNode())
 389             continue;
 390         Element* element = toElement(node);
 391         if (selectorListMatches<SelectorQueryTrait>(rootNode, *element, output) && SelectorQueryTrait::shouldOnlyMatchFirstElement)
 392             return;
 393     }
 394 }
 395
 396 const CSSSelector* SelectorDataList::selectorForIdLookup(const CSSSelector& firstSelector) const
 397 {
 398     for (const CSSSelector* selector = &firstSelector; selector; selector = selector->tagHistory()) {
 399         if (selector->match() == CSSSelector::Id)
 400             return selector;
 401         if (selector->relation() != CSSSelector::SubSelector)
 402             break;
 403     }
 404     return 0;
 405 }
 406
 407 template <typename SelectorQueryTrait>
 408 void SelectorDataList::execute(ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 409 {
 410     if (!canUseFastQuery(rootNode)) {
 411         if (m_crossesTreeBoundary) {
 412             rootNode.document().updateDistributionForNodeIfNeeded(&rootNode);
 413             executeSlowTraversingShadowTree<SelectorQueryTrait>(rootNode, output);
 414         } else {
 415             executeSlow<SelectorQueryTrait>(rootNode, output);
 416         }
 417         return;
 418     }
 419
 420     ASSERT(m_selectors.size() == 1);
 421
 422     const CSSSelector& selector = *m_selectors[0];
 423     const CSSSelector& firstSelector = selector;
 424
 425     // Fast path for querySelector*('#id'), querySelector*('tag#id').
 426     if (const CSSSelector* idSelector = selectorForIdLookup(firstSelector)) {
 427         const AtomicString& idToMatch = idSelector->value();
 428         if (rootNode.treeScope().containsMultipleElementsWithId(idToMatch)) {
 429             const WillBeHeapVector<RawPtrWillBeMember<Element> >& elements = rootNode.treeScope().getAllElementsById(idToMatch);
 430             size_t count = elements.size();
 431             for (size_t i = 0; i < count; ++i) {
 432                 Element& element = *elements[i];
 433                 if (!(isTreeScopeRoot(rootNode) || element.isDescendantOf(&rootNode)))
 434                     continue;
 435                 if (selectorMatches(selector, element, rootNode)) {
 436                     SelectorQueryTrait::appendElement(output, element);
 437                     if (SelectorQueryTrait::shouldOnlyMatchFirstElement)
 438                         return;
 439                 }
 440             }
 441             return;
 442         }
 443         Element* element = rootNode.treeScope().getElementById(idToMatch);
 444         if (!element || !(isTreeScopeRoot(rootNode) || element->isDescendantOf(&rootNode)))
 445             return;
 446         if (selectorMatches(selector, *element, rootNode))
 447             SelectorQueryTrait::appendElement(output, *element);
 448         return;
 449     }
 450
 451     if (!firstSelector.tagHistory()) {
 452         // Fast path for querySelector*('.foo'), and querySelector*('div').
 453         switch (firstSelector.match()) {
 454         case CSSSelector::Class:
 455             collectElementsByClassName<SelectorQueryTrait>(rootNode, firstSelector.value(), output);
 456             return;
 457         case CSSSelector::Tag:
 458             collectElementsByTagName<SelectorQueryTrait>(rootNode, firstSelector.tagQName(), output);
 459             return;
 460         default:
 461             break; // If we need another fast path, add here.
 462         }
 463     }
 464
 465     findTraverseRootsAndExecute<SelectorQueryTrait>(rootNode, output);
 466 }
 467
 468 PassOwnPtr<SelectorQuery> SelectorQuery::adopt(CSSSelectorList& selectorList)
 469 {
 470     return adoptPtr(new SelectorQuery(selectorList));
 471 }
 472
 473 SelectorQuery::SelectorQuery(CSSSelectorList& selectorList)
 474 {
 475     m_selectorList.adopt(selectorList);
 476     m_selectors.initialize(m_selectorList);
 477 }
 478
 479 bool SelectorQuery::matches(Element& element) const
 480 {
 481     return m_selectors.matches(element);
 482 }
 483
 484 PassRefPtrWillBeRawPtr<StaticElementList> SelectorQuery::queryAll(ContainerNode& rootNode) const
 485 {
 486     return m_selectors.queryAll(rootNode);
 487 }
 488
 489 PassRefPtrWillBeRawPtr<Element> SelectorQuery::queryFirst(ContainerNode& rootNode) const
 490 {
 491     return m_selectors.queryFirst(rootNode);
 492 }
 493
 494 SelectorQuery* SelectorQueryCache::add(const AtomicString& selectors, const Document& document, ExceptionState& exceptionState)
 495 {
 496     HashMap<AtomicString, OwnPtr<SelectorQuery> >::iterator it = m_entries.find(selectors);
 497     if (it != m_entries.end())
 498         return it->value.get();
 499
 500     CSSParser parser(CSSParserContext(document, 0));
 501     CSSSelectorList selectorList;
 502     parser.parseSelector(selectors, selectorList);
 503
 504     if (!selectorList.first()) {
 505         exceptionState.throwDOMException(SyntaxError, "'" + selectors + "' is not a valid selector.");
 506         return 0;
 507     }
 508
 509     // throw a NamespaceError if the selector includes any namespace prefixes.
 510     if (selectorList.selectorsNeedNamespaceResolution()) {
 511         exceptionState.throwDOMException(NamespaceError, "'" + selectors + "' contains namespaces, which are not supported.");
 512         return 0;
 513     }
 514
 515     const unsigned maximumSelectorQueryCacheSize = 256;
 516     if (m_entries.size() == maximumSelectorQueryCacheSize)
 517         m_entries.remove(m_entries.begin());
 518
 519     return m_entries.add(selectors, SelectorQuery::adopt(selectorList)).storedValue->value.get();
 520 }
 521
 522 void SelectorQueryCache::invalidate()
 523 {
 524     m_entries.clear();
 525 }
 526
 527 }