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/*
* 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) 2013 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 "SelectorCheckerFastPath.h"
#include "HTMLDocument.h"
#include "HTMLNames.h"
#include "StyledElement.h"
namespace WebCore {
using namespace HTMLNames;
namespace {
template <bool checkValue(const Element*, const CSSSelector*)>
inline bool fastCheckSingleSelector(const CSSSelector*& selector, const Element*& element, const CSSSelector*& topChildOrSubselector, const Element*& topChildOrSubselectorMatchElement)
{
for (; element; element = element->parentElement()) {
if (checkValue(element, selector)) {
if (selector->relation() == CSSSelector::Descendant)
topChildOrSubselector = 0;
else if (!topChildOrSubselector) {
ASSERT(selector->relation() == CSSSelector::Child || selector->relation() == CSSSelector::SubSelector);
topChildOrSubselector = selector;
topChildOrSubselectorMatchElement = element;
}
if (selector->relation() != CSSSelector::SubSelector)
element = element->parentElement();
selector = selector->tagHistory();
return true;
}
if (topChildOrSubselector) {
// Child or subselector check failed.
// If the match element is null, topChildOrSubselector was also the very topmost selector and had to match
// the original element we were checking.
if (!topChildOrSubselectorMatchElement)
return false;
// There may be other matches down the ancestor chain.
// Rewind to the topmost child or subselector and the element it matched, continue checking ancestors.
selector = topChildOrSubselector;
element = topChildOrSubselectorMatchElement->parentElement();
topChildOrSubselector = 0;
return true;
}
}
return false;
}
inline bool checkClassValue(const Element* element, const CSSSelector* selector)
{
return element->hasClass() && element->classNames().contains(selector->value());
}
inline bool checkIDValue(const Element* element, const CSSSelector* selector)
{
return element->hasID() && element->idForStyleResolution().impl() == selector->value().impl();
}
inline bool checkExactAttributeValue(const Element* element, const CSSSelector* selector)
{
return SelectorChecker::checkExactAttribute(element, selector, selector->attribute(), selector->value().impl());
}
inline bool checkTagValue(const Element* element, const CSSSelector* selector)
{
return SelectorChecker::tagMatches(element, selector->tagQName());
}
}
SelectorCheckerFastPath::SelectorCheckerFastPath(const CSSSelector* selector, const Element* element)
: m_selector(selector)
, m_element(element)
{
}
bool SelectorCheckerFastPath::matchesRightmostSelector(SelectorChecker::VisitedMatchType visitedMatchType) const
{
ASSERT(SelectorCheckerFastPath::canUse(m_selector));
switch (m_selector->m_match) {
case CSSSelector::Tag:
return checkTagValue(m_element, m_selector);
case CSSSelector::Class:
return checkClassValue(m_element, m_selector);
case CSSSelector::Id:
return checkIDValue(m_element, m_selector);
case CSSSelector::Exact:
case CSSSelector::Set:
return checkExactAttributeValue(m_element, m_selector);
case CSSSelector::PseudoClass:
return commonPseudoClassSelectorMatches(visitedMatchType);
default:
ASSERT_NOT_REACHED();
}
return false;
}
bool SelectorCheckerFastPath::matches() const
{
ASSERT(matchesRightmostSelector(SelectorChecker::VisitedMatchEnabled));
const CSSSelector* selector = m_selector;
const Element* element = m_element;
const CSSSelector* topChildOrSubselector = 0;
const Element* topChildOrSubselectorMatchElement = 0;
if (selector->relation() == CSSSelector::Child || selector->relation() == CSSSelector::SubSelector)
topChildOrSubselector = selector;
if (selector->relation() != CSSSelector::SubSelector)
element = element->parentElement();
selector = selector->tagHistory();
// We know this compound selector has descendant, child and subselector combinators only and all components are simple.
while (selector) {
switch (selector->m_match) {
case CSSSelector::Class:
if (!fastCheckSingleSelector<checkClassValue>(selector, element, topChildOrSubselector, topChildOrSubselectorMatchElement))
return false;
break;
case CSSSelector::Id:
if (!fastCheckSingleSelector<checkIDValue>(selector, element, topChildOrSubselector, topChildOrSubselectorMatchElement))
return false;
break;
case CSSSelector::Tag:
if (!fastCheckSingleSelector<checkTagValue>(selector, element, topChildOrSubselector, topChildOrSubselectorMatchElement))
return false;
break;
case CSSSelector::Set:
case CSSSelector::Exact:
if (!fastCheckSingleSelector<checkExactAttributeValue>(selector, element, topChildOrSubselector, topChildOrSubselectorMatchElement))
return false;
break;
default:
ASSERT_NOT_REACHED();
}
}
return true;
}
static inline bool isFastCheckableRelation(CSSSelector::Relation relation)
{
return relation == CSSSelector::Descendant || relation == CSSSelector::Child || relation == CSSSelector::SubSelector;
}
static inline bool isFastCheckableMatch(const CSSSelector* selector)
{
if (selector->m_match == CSSSelector::Set) {
// Style attribute is generated lazily but the fast path doesn't trigger it.
// Disallow them here rather than making the fast path more branchy.
return selector->attribute() != styleAttr;
}
if (selector->m_match == CSSSelector::Exact)
return selector->attribute() != styleAttr && HTMLDocument::isCaseSensitiveAttribute(selector->attribute());
return selector->m_match == CSSSelector::Tag || selector->m_match == CSSSelector::Id || selector->m_match == CSSSelector::Class;
}
static inline bool isFastCheckableRightmostSelector(const CSSSelector* selector)
{
if (!isFastCheckableRelation(selector->relation()))
return false;
return isFastCheckableMatch(selector) || SelectorChecker::isCommonPseudoClassSelector(selector);
}
bool SelectorCheckerFastPath::canUse(const CSSSelector* selector)
{
if (!isFastCheckableRightmostSelector(selector))
return false;
for (selector = selector->tagHistory(); selector; selector = selector->tagHistory()) {
if (!isFastCheckableRelation(selector->relation()))
return false;
if (!isFastCheckableMatch(selector))
return false;
}
return true;
}
bool SelectorCheckerFastPath::commonPseudoClassSelectorMatches(SelectorChecker::VisitedMatchType visitedMatchType) const
{
ASSERT(SelectorChecker::isCommonPseudoClassSelector(m_selector));
switch (m_selector->pseudoType()) {
case CSSSelector::PseudoLink:
case CSSSelector::PseudoAnyLink:
return m_element->isLink();
case CSSSelector::PseudoVisited:
return m_element->isLink() && visitedMatchType == SelectorChecker::VisitedMatchEnabled;
case CSSSelector::PseudoFocus:
return SelectorChecker::matchesFocusPseudoClass(m_element);
default:
ASSERT_NOT_REACHED();
}
return true;
}
}
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