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/*
* 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"
#if ENABLE(XPATH)
#include "XPathNodeSet.h"
#include "Attr.h"
#include "Element.h"
#include "Node.h"
namespace WebCore {
namespace XPath {
static inline Node* parentWithDepth(unsigned depth, const Vector<Node*>& parents)
{
ASSERT(parents.size() >= depth + 1);
return parents[parents.size() - 1 - depth];
}
static void sortBlock(unsigned from, unsigned to, Vector<Vector<Node*> >& parentMatrix, bool mayContainAttributeNodes)
{
ASSERT(from + 1 < to); // Should not call this function with less that two nodes to sort.
unsigned minDepth = UINT_MAX;
for (unsigned i = from; i < to; ++i) {
unsigned depth = parentMatrix[i].size() - 1;
if (minDepth > depth)
minDepth = depth;
}
// Find the common ancestor.
unsigned commonAncestorDepth = minDepth;
Node* commonAncestor;
while (true) {
commonAncestor = parentWithDepth(commonAncestorDepth, parentMatrix[from]);
if (commonAncestorDepth == 0)
break;
bool allEqual = true;
for (unsigned i = from + 1; i < to; ++i) {
if (commonAncestor != parentWithDepth(commonAncestorDepth, parentMatrix[i])) {
allEqual = false;
break;
}
}
if (allEqual)
break;
--commonAncestorDepth;
}
if (commonAncestorDepth == minDepth) {
// One of the nodes is the common ancestor => it is the first in document order.
// Find it and move it to the beginning.
for (unsigned i = from; i < to; ++i)
if (commonAncestor == parentMatrix[i][0]) {
parentMatrix[i].swap(parentMatrix[from]);
if (from + 2 < to)
sortBlock(from + 1, to, parentMatrix, mayContainAttributeNodes);
return;
}
}
if (mayContainAttributeNodes && commonAncestor->isElementNode()) {
// The attribute nodes and namespace nodes of an element occur before the children of the element.
// The namespace nodes are defined to occur before the attribute nodes.
// The relative order of namespace nodes is implementation-dependent.
// The relative order of attribute nodes is implementation-dependent.
unsigned sortedEnd = from;
// FIXME: namespace nodes are not implemented.
for (unsigned i = sortedEnd; i < to; ++i) {
Node* n = parentMatrix[i][0];
if (n->isAttributeNode() && static_cast<Attr*>(n)->ownerElement() == commonAncestor)
parentMatrix[i].swap(parentMatrix[sortedEnd++]);
}
if (sortedEnd != from) {
if (to - sortedEnd > 1)
sortBlock(sortedEnd, to, parentMatrix, mayContainAttributeNodes);
return;
}
}
// Children nodes of the common ancestor induce a subdivision of our node-set.
// Sort it according to this subdivision, and recursively sort each group.
HashSet<Node*> parentNodes;
for (unsigned i = from; i < to; ++i)
parentNodes.add(parentWithDepth(commonAncestorDepth + 1, parentMatrix[i]));
unsigned previousGroupEnd = from;
unsigned groupEnd = from;
for (Node* n = commonAncestor->firstChild(); n; n = n->nextSibling()) {
// If parentNodes contains the node, perform a linear search to move its children in the node-set to the beginning.
if (parentNodes.contains(n)) {
for (unsigned i = groupEnd; i < to; ++i)
if (parentWithDepth(commonAncestorDepth + 1, parentMatrix[i]) == n)
parentMatrix[i].swap(parentMatrix[groupEnd++]);
if (groupEnd - previousGroupEnd > 1)
sortBlock(previousGroupEnd, groupEnd, parentMatrix, mayContainAttributeNodes);
ASSERT(previousGroupEnd != groupEnd);
previousGroupEnd = groupEnd;
#ifndef NDEBUG
parentNodes.remove(n);
#endif
}
}
ASSERT(parentNodes.isEmpty());
}
void NodeSet::sort() const
{
if (m_isSorted)
return;
unsigned nodeCount = m_nodes.size();
if (nodeCount < 2) {
const_cast<bool&>(m_isSorted) = true;
return;
}
bool containsAttributeNodes = false;
Vector<Vector<Node*> > parentMatrix(nodeCount);
for (unsigned i = 0; i < nodeCount; ++i) {
Vector<Node*>& parentsVector = parentMatrix[i];
Node* n = m_nodes[i].get();
parentsVector.append(n);
if (n->isAttributeNode()) {
n = static_cast<Attr*>(n)->ownerElement();
parentsVector.append(n);
containsAttributeNodes = true;
}
while ((n = n->parentNode()))
parentsVector.append(n);
}
sortBlock(0, nodeCount, parentMatrix, containsAttributeNodes);
// It is not possible to just assign the result to m_nodes, because some nodes may get dereferenced and destroyed.
Vector<RefPtr<Node> > sortedNodes;
sortedNodes.reserveInitialCapacity(nodeCount);
for (unsigned i = 0; i < nodeCount; ++i)
sortedNodes.append(parentMatrix[i][0]);
const_cast<Vector<RefPtr<Node> >& >(m_nodes).swap(sortedNodes);
}
void NodeSet::reverse()
{
if (m_nodes.isEmpty())
return;
unsigned from = 0;
unsigned to = m_nodes.size() - 1;
while (from < to) {
m_nodes[from].swap(m_nodes[to]);
++from;
--to;
}
}
Node* NodeSet::firstNode() const
{
if (isEmpty())
return 0;
sort(); // FIXME: fully sorting the node-set just to find its first node is wasteful.
return m_nodes.at(0).get();
}
Node* NodeSet::anyNode() const
{
if (isEmpty())
return 0;
return m_nodes.at(0).get();
}
}
}
#endif // ENABLE(XPATH)
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