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/*
* Copyright (C) 2005 Frerich Raabe <raabe@kde.org>
* Copyright (C) 2006, 2009, 2013 Apple Inc. All rights reserved.
* Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "XPathPath.h"
#include "Document.h"
#include "XPathPredicate.h"
#include "XPathStep.h"
namespace WebCore {
namespace XPath {
Filter::Filter(std::unique_ptr<Expression> expression, Vector<std::unique_ptr<Expression>> predicates)
: m_expression(WTFMove(expression)), m_predicates(WTFMove(predicates))
{
setIsContextNodeSensitive(m_expression->isContextNodeSensitive());
setIsContextPositionSensitive(m_expression->isContextPositionSensitive());
setIsContextSizeSensitive(m_expression->isContextSizeSensitive());
}
Value Filter::evaluate() const
{
Value result = m_expression->evaluate();
NodeSet& nodes = result.modifiableNodeSet();
nodes.sort();
EvaluationContext& evaluationContext = Expression::evaluationContext();
for (auto& predicate : m_predicates) {
NodeSet newNodes;
evaluationContext.size = nodes.size();
evaluationContext.position = 0;
for (auto& node : nodes) {
evaluationContext.node = node;
++evaluationContext.position;
if (evaluatePredicate(*predicate))
newNodes.append(node.copyRef());
}
nodes = WTFMove(newNodes);
}
return result;
}
LocationPath::LocationPath()
: m_isAbsolute(false)
{
setIsContextNodeSensitive(true);
}
Value LocationPath::evaluate() const
{
EvaluationContext& evaluationContext = Expression::evaluationContext();
EvaluationContext backupContext = evaluationContext;
// http://www.w3.org/TR/xpath/
// Section 2, Location Paths:
// "/ selects the document root (which is always the parent of the document element)"
// "A / by itself selects the root node of the document containing the context node."
// In the case of a tree that is detached from the document, we violate
// the spec and treat / as the root node of the detached tree.
// This is for compatibility with Firefox, and also seems like a more
// logical treatment of where you would expect the "root" to be.
Node* context = evaluationContext.node.get();
if (m_isAbsolute && !context->isDocumentNode())
context = &context->rootNode();
NodeSet nodes;
nodes.append(context);
evaluate(nodes);
evaluationContext = backupContext;
return Value(WTFMove(nodes));
}
void LocationPath::evaluate(NodeSet& nodes) const
{
bool resultIsSorted = nodes.isSorted();
for (auto& step : m_steps) {
NodeSet newNodes;
HashSet<Node*> newNodesSet;
bool needToCheckForDuplicateNodes = !nodes.subtreesAreDisjoint() || (step->axis() != Step::ChildAxis && step->axis() != Step::SelfAxis
&& step->axis() != Step::DescendantAxis && step->axis() != Step::DescendantOrSelfAxis && step->axis() != Step::AttributeAxis);
if (needToCheckForDuplicateNodes)
resultIsSorted = false;
// This is a simplified check that can be improved to handle more cases.
if (nodes.subtreesAreDisjoint() && (step->axis() == Step::ChildAxis || step->axis() == Step::SelfAxis))
newNodes.markSubtreesDisjoint(true);
for (auto& node : nodes) {
NodeSet matches;
step->evaluate(*node, matches);
if (!matches.isSorted())
resultIsSorted = false;
for (auto& match : matches) {
if (!needToCheckForDuplicateNodes || newNodesSet.add(match.get()).isNewEntry)
newNodes.append(match.copyRef());
}
}
nodes = WTFMove(newNodes);
}
nodes.markSorted(resultIsSorted);
}
void LocationPath::appendStep(std::unique_ptr<Step> step)
{
unsigned stepCount = m_steps.size();
if (stepCount) {
bool dropSecondStep;
optimizeStepPair(*m_steps[stepCount - 1], *step, dropSecondStep);
if (dropSecondStep)
return;
}
step->optimize();
m_steps.append(WTFMove(step));
}
void LocationPath::prependStep(std::unique_ptr<Step> step)
{
if (m_steps.size()) {
bool dropSecondStep;
optimizeStepPair(*step, *m_steps[0], dropSecondStep);
if (dropSecondStep) {
m_steps[0] = WTFMove(step);
return;
}
}
step->optimize();
m_steps.insert(0, WTFMove(step));
}
Path::Path(std::unique_ptr<Expression> filter, std::unique_ptr<LocationPath> path)
: m_filter(WTFMove(filter))
, m_path(WTFMove(path))
{
setIsContextNodeSensitive(m_filter->isContextNodeSensitive());
setIsContextPositionSensitive(m_filter->isContextPositionSensitive());
setIsContextSizeSensitive(m_filter->isContextSizeSensitive());
}
Value Path::evaluate() const
{
Value result = m_filter->evaluate();
NodeSet& nodes = result.modifiableNodeSet();
m_path->evaluate(nodes);
return result;
}
}
}