third_party/WebKit/Source/core/html/HTMLContentElement.cpp

/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#include "core/html/HTMLContentElement.h"

#include "core/HTMLNames.h"
#include "core/css/SelectorChecker.h"
#include "core/css/parser/CSSParser.h"
#include "core/dom/QualifiedName.h"
#include "core/dom/shadow/ElementShadow.h"
#include "core/dom/shadow/ElementShadowV0.h"
#include "core/dom/shadow/ShadowRoot.h"
#include "core/frame/UseCounter.h"
#include "platform/RuntimeEnabledFeatures.h"

namespace blink {

using namespace HTMLNames;

HTMLContentElement* HTMLContentElement::create(
    Document& document,
    HTMLContentSelectFilter* filter) {
  return new HTMLContentElement(document, filter);
}

inline HTMLContentElement::HTMLContentElement(Document& document,
                                              HTMLContentSelectFilter* filter)
    : InsertionPoint(contentTag, document),
      m_shouldParseSelect(false),
      m_isValidSelector(true),
      m_filter(filter) {
  UseCounter::count(document, UseCounter::HTMLContentElement);
}

HTMLContentElement::~HTMLContentElement() {}

DEFINE_TRACE(HTMLContentElement) {
  visitor->trace(m_filter);
  InsertionPoint::trace(visitor);
}

void HTMLContentElement::parseSelect() {
  DCHECK(m_shouldParseSelect);

  m_selectorList = CSSParser::parseSelector(
      CSSParserContext::create(document()), nullptr, m_select);
  m_shouldParseSelect = false;
  m_isValidSelector = validateSelect();
  if (!m_isValidSelector)
    m_selectorList = CSSSelectorList();
}

void HTMLContentElement::parseAttribute(
    const AttributeModificationParams& params) {
  if (params.name == selectAttr) {
    if (ShadowRoot* root = containingShadowRoot()) {
      if (!root->isV1() && root->owner())
        root->owner()->v0().willAffectSelector();
    }
    m_shouldParseSelect = true;
    m_select = params.newValue;
  } else {
    InsertionPoint::parseAttribute(params);
  }
}

static inline bool includesDisallowedPseudoClass(const CSSSelector& selector) {
  if (selector.getPseudoType() == CSSSelector::PseudoNot) {
    const CSSSelector* subSelector = selector.selectorList()->first();
    return subSelector->match() == CSSSelector::PseudoClass;
  }
  return selector.match() == CSSSelector::PseudoClass;
}

bool HTMLContentElement::validateSelect() const {
  DCHECK(!m_shouldParseSelect);

  if (m_select.isNull() || m_select.isEmpty())
    return true;

  if (!m_selectorList.isValid())
    return false;

  for (const CSSSelector* selector = m_selectorList.first(); selector;
       selector = m_selectorList.next(*selector)) {
    if (!selector->isCompound())
      return false;
    for (const CSSSelector* subSelector = selector; subSelector;
         subSelector = subSelector->tagHistory()) {
      if (includesDisallowedPseudoClass(*subSelector))
        return false;
    }
  }
  return true;
}

// TODO(esprehn): element should really be const, but matching a selector is not
// const for some SelectorCheckingModes (mainly ResolvingStyle) where it sets
// dynamic restyle flags on elements.
bool HTMLContentElement::matchSelector(Element& element) const {
  SelectorChecker::Init init;
  init.mode = SelectorChecker::QueryingRules;
  SelectorChecker checker(init);
  SelectorChecker::SelectorCheckingContext context(
      &element, SelectorChecker::VisitedMatchDisabled);
  for (const CSSSelector* selector = selectorList().first(); selector;
       selector = CSSSelectorList::next(*selector)) {
    context.selector = selector;
    if (checker.match(context))
      return true;
  }
  return false;
}

}  // namespace blink