Source/WebCore/style/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 "config.h"
#include "PageRuleCollector.h"

#include "CSSDefaultStyleSheets.h"
#include "StyleProperties.h"
#include "StyleRule.h"

namespace WebCore {
namespace Style {

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

bool PageRuleCollector::isLeftPage(int pageIndex) const
{
    bool isFirstPageLeft = false;
    if (!m_state.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 emptyString();
}

void PageRuleCollector::matchAllPageRules(int pageIndex)
{
    const bool isLeft = isLeftPage(pageIndex);
    const bool isFirst = isFirstPage(pageIndex);
    const String page = pageName(pageIndex);
    
    matchPageRules(CSSDefaultStyleSheets::defaultPrintStyle, isLeft, isFirst, page);
    matchPageRules(m_ruleSets.userStyle(), isLeft, isFirst, page);
    // Only consider the global author RuleSet for @page rules, as per the HTML5 spec.
    if (m_ruleSets.isAuthorStyleDefined())
        matchPageRules(&m_ruleSets.authorStyle(), isLeft, isFirst, page);
}

void PageRuleCollector::matchPageRules(RuleSet* rules, bool isLeftPage, bool isFirstPage, const String& pageName)
{
    if (!rules)
        return;

    Vector<StyleRulePage*> matchedPageRules;
    matchPageRulesForList(matchedPageRules, rules->pageRules(), isLeftPage, isFirstPage, pageName);
    if (matchedPageRules.isEmpty())
        return;

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

    for (unsigned i = 0; i < matchedPageRules.size(); i++)
        m_result.authorDeclarations.append({ &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 AtomString& localName = component->tagQName().localName();
            if (localName != starAtom() && localName != pageName)
                return false;
        } else if (component->match() == CSSSelector::PagePseudoClass) {
            CSSSelector::PagePseudoClassType pseudoType = component->pagePseudoClassType();
            if ((pseudoType == CSSSelector::PagePseudoClassLeft && !isLeftPage)
                || (pseudoType == CSSSelector::PagePseudoClassRight && isLeftPage)
                || (pseudoType == CSSSelector::PagePseudoClassFirst && !isFirstPage))
            {
                return false;
            }
        }
    }
    return true;
}

void PageRuleCollector::matchPageRulesForList(Vector<StyleRulePage*>& matchedRules, const Vector<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 StyleProperties& properties = rule->properties();
        if (properties.isEmpty())
            continue;

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

} // namespace Style
} // namespace WebCore