third_party/WebKit/Source/core/css/PageRuleCollector.cpp

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
 * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
 * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc.
 * All rights reserved.
 * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
 * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
 * (http://www.torchmobile.com/)
 * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
 * Copyright (C) Research In Motion Limited 2011. All rights reserved.
 * Copyright (C) 2012 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "core/css/PageRuleCollector.h"

#include "core/css/StylePropertySet.h"
#include "core/css/StyleRule.h"
#include "core/css/resolver/StyleResolverState.h"
#include <algorithm>

namespace blink {

static inline bool comparePageRules(const StyleRulePage* r1,
                                    const StyleRulePage* r2) {
  return r1->selector()->specificity() < r2->selector()->specificity();
}

bool PageRuleCollector::isLeftPage(const ComputedStyle* rootElementStyle,
                                   int pageIndex) const {
  bool isFirstPageLeft = false;
  ASSERT(rootElementStyle);
  if (!rootElementStyle->isLeftToRightDirection())
    isFirstPageLeft = true;

  return (pageIndex + (isFirstPageLeft ? 1 : 0)) % 2;
}

bool PageRuleCollector::isFirstPage(int pageIndex) const {
  // FIXME: In case of forced left/right page, page at index 1 (not 0) can be
  // the first page.
  return (!pageIndex);
}

String PageRuleCollector::pageName(int /* pageIndex */) const {
  // FIXME: Implement page index to page name mapping.
  return "";
}

PageRuleCollector::PageRuleCollector(const ComputedStyle* rootElementStyle,
                                     int pageIndex)
    : m_isLeftPage(isLeftPage(rootElementStyle, pageIndex)),
      m_isFirstPage(isFirstPage(pageIndex)),
      m_pageName(pageName(pageIndex)) {}

void PageRuleCollector::matchPageRules(RuleSet* rules) {
  if (!rules)
    return;

  rules->compactRulesIfNeeded();
  HeapVector<Member<StyleRulePage>> matchedPageRules;
  matchPageRulesForList(matchedPageRules, rules->pageRules(), m_isLeftPage,
                        m_isFirstPage, m_pageName);
  if (matchedPageRules.isEmpty())
    return;

  std::stable_sort(matchedPageRules.begin(), matchedPageRules.end(),
                   comparePageRules);

  for (unsigned i = 0; i < matchedPageRules.size(); i++)
    m_result.addMatchedProperties(&matchedPageRules[i]->properties());
}

static bool checkPageSelectorComponents(const CSSSelector* selector,
                                        bool isLeftPage,
                                        bool isFirstPage,
                                        const String& pageName) {
  for (const CSSSelector* component = selector; component;
       component = component->tagHistory()) {
    if (component->match() == CSSSelector::Tag) {
      const AtomicString& localName = component->tagQName().localName();
      if (localName != starAtom && localName != pageName)
        return false;
    }

    CSSSelector::PseudoType pseudoType = component->getPseudoType();
    if ((pseudoType == CSSSelector::PseudoLeftPage && !isLeftPage) ||
        (pseudoType == CSSSelector::PseudoRightPage && isLeftPage) ||
        (pseudoType == CSSSelector::PseudoFirstPage && !isFirstPage)) {
      return false;
    }
  }
  return true;
}

void PageRuleCollector::matchPageRulesForList(
    HeapVector<Member<StyleRulePage>>& matchedRules,
    const HeapVector<Member<StyleRulePage>>& rules,
    bool isLeftPage,
    bool isFirstPage,
    const String& pageName) {
  for (unsigned i = 0; i < rules.size(); ++i) {
    StyleRulePage* rule = rules[i];

    if (!checkPageSelectorComponents(rule->selector(), isLeftPage, isFirstPage,
                                     pageName))
      continue;

    // If the rule has no properties to apply, then ignore it.
    const StylePropertySet& properties = rule->properties();
    if (properties.isEmpty())
      continue;

    // Add this rule to our list of matched rules.
    matchedRules.append(rule);
  }
}

}  // namespace blink