308 lines
9.5 KiB
C++
308 lines
9.5 KiB
C++
/*
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* (C) Copyright The MITRE Corporation 1999 All rights reserved.
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*
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* The contents of this file are subject to the Mozilla Public License
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* Version 1.0 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* The program provided "as is" without any warranty express or
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* implied, including the warranty of non-infringement and the implied
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* warranties of merchantibility and fitness for a particular purpose.
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* The Copyright owner will not be liable for any damages suffered by
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* you as a result of using the Program. In no event will the Copyright
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* owner be liable for any special, indirect or consequential damages or
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* lost profits even if the Copyright owner has been advised of the
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* possibility of their occurrence.
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*
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* Please see release.txt distributed with this file for more information.
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*
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*/
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/**
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* LocationStep
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* @author <a href="mailto:kvisco@mitre.org">Keith Visco</a>
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**/
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#include "Expr.h"
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/**
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* Creates a new LocationStep using the default Axis Identifier and no
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* NodeExpr (which matches nothing)
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**/
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LocationStep::LocationStep() : PredicateList() {
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nodeExpr = 0;
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this->axisIdentifier = CHILD_AXIS;
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} //-- LocationStep
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/**
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* Creates a new LocationStep using the default Axis Identifier and
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* the given NodeExpr
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* @param nodeExpr the NodeExpr to use when matching Nodes
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**/
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LocationStep::LocationStep(NodeExpr* nodeExpr) : PredicateList() {
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this->nodeExpr = nodeExpr;
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this->axisIdentifier = CHILD_AXIS;
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} //-- LocationStep
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/**
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* Creates a new LocationStep using the given NodeExpr and Axis Identifier
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* @param nodeExpr the NodeExpr to use when matching Nodes
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* @param axisIdentifier the Axis Identifier in which to search for nodes
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**/
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LocationStep::LocationStep(NodeExpr* nodeExpr, short axisIdentifier) : PredicateList() {
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this->nodeExpr = nodeExpr;
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this->axisIdentifier = axisIdentifier;
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} //-- LocationStep
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/**
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* Destroys this LocationStep
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* All predicates will be deleted
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* The NodeExpr will be deleted
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**/
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LocationStep::~LocationStep() {
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delete nodeExpr;
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} //-- ~LocationStep
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/**
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* Sets the Axis Identifier for this LocationStep
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* @param axisIdentifier the Axis in which to search for nodes
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**/
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void LocationStep::setAxisIdentifier(short axisIdentifier) {
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this->axisIdentifier = axisIdentifier;
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} //-- setAxisIdentifier
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/**
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* Sets the NodeExpr of this LocationStep for use when matching nodes
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* @param nodeExpr the NodeExpr to use when matching nodes
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**/
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void LocationStep::setNodeExpr(NodeExpr* nodeExpr) {
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this->nodeExpr = nodeExpr;
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} //-- setNodeExpr
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//------------------------------------/
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//- Virtual methods from PatternExpr -/
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//------------------------------------/
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/**
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* Evaluates this Expr based on the given context node and processor state
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* @param context the context node for evaluation of this Expr
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* @param ps the ProcessorState containing the stack information needed
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* for evaluation
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* @return the result of the evaluation
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* @see PatternExpr
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**/
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ExprResult* LocationStep::evaluate(Node* context, ContextState* cs) {
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NodeSet* nodes = new NodeSet();
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if (( !context ) || (! nodeExpr )) return nodes;
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Node* node = context;
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switch (axisIdentifier) {
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case ANCESTOR_AXIS :
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if (node) node = context->getParentNode();
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//-- do not break here
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case ANCESTOR_OR_SELF_AXIS :
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while (node) {
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if (nodeExpr->matches(node, context, cs)) {
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nodes->add(node);
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}
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node = node->getParentNode();
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}
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break;
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case ATTRIBUTE_AXIS :
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{
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NamedNodeMap* atts = context->getAttributes();
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if ( atts ) {
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for ( int i = 0; i < atts->getLength(); i++ ) {
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Attr* attr = (Attr*)atts->item(i);
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if ( nodeExpr->matches(attr, context, cs) ) nodes->add(attr);
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}
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}
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break;
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}
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case DESCENDANT_OR_SELF_AXIS :
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if ( nodeExpr->matches(context, context, cs))
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nodes->add(context);
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//-- do not break here
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case DESCENDANT_AXIS :
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fromDescendants(context, cs, nodes);
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break;
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case FOLLOWING_AXIS :
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{
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node = context->getNextSibling();
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while (node) {
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if (nodeExpr->matches(node, context, cs))
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nodes->add(node);
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if (node->hasChildNodes())
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fromDescendants(node, cs, nodes);
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Node* tmpNode = node->getNextSibling();
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if (!tmpNode) {
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node = node->getParentNode();
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if ((node) && (node->getNodeType() != Node::DOCUMENT_NODE))
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node = node->getNextSibling();
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}
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else node = tmpNode;
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}
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break;
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}
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case FOLLOWING_SIBLING_AXIS :
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node = context->getNextSibling();
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while (node) {
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if (nodeExpr->matches(node, context, cs))
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nodes->add(node);
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node = node->getNextSibling();
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}
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break;
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case NAMESPACE_AXIS : //-- not yet implemented
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cout << "namespace axis not yet implemented"<<endl;
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break;
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case PARENT_AXIS :
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{
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Node* parent = context->getParentNode();
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if ( nodeExpr->matches(parent, context, cs) )
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nodes->add(parent);
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break;
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}
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case PRECEDING_AXIS :
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node = context->getPreviousSibling();
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if ( !node ) node = context->getParentNode();
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while (node) {
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if (nodeExpr->matches(node, context, cs))
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nodes->add(node);
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Node* temp = node->getPreviousSibling();
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if (!temp) node = node->getParentNode();
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else node = temp;
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}
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break;
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case PRECEDING_SIBLING_AXIS:
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node = context->getPreviousSibling();
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while (node) {
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if (nodeExpr->matches(node, context, cs))
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nodes->add(node);
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node = node->getPreviousSibling();
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}
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break;
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case SELF_AXIS :
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if ( nodeExpr->matches(context, context, cs) )
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nodes->add(context);
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break;
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default: //-- Children Axis
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{
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NodeList* nl = context->getChildNodes();
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for (int i = 0; i < nl->getLength(); i++ ) {
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if ( nodeExpr->matches(nl->item(i), context, cs) )
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nodes->add(nl->item(i));
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}
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break;
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}
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} //-- switch
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//-- apply predicates
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evaluatePredicates(nodes, cs);
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return nodes;
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} //-- evaluate
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/**
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* Returns the default priority of this Pattern based on the given Node,
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* context Node, and ContextState.
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* If this pattern does not match the given Node under the current context Node and
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* ContextState then Negative Infinity is returned.
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**/
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double LocationStep::getDefaultPriority(Node* node, Node* context, ContextState* cs) {
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if ( !nodeExpr ) {
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return Double::NEGATIVE_INFINITY;
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}
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if (!PredicateList::isEmpty()) {
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return 0.5;
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}
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return nodeExpr->getDefaultPriority(node, context, cs);
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} //-- getDefaultPriority
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void LocationStep::fromDescendants(Node* context, ContextState* cs, NodeSet* nodes) {
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if (( !context ) || (! nodeExpr )) return;
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NodeList* nl = context->getChildNodes();
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for (int i = 0; i < nl->getLength(); i++) {
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Node* child = nl->item(i);
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if (nodeExpr->matches(child, context, cs))
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nodes->add(child);
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//-- check childs descendants
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if (child->hasChildNodes()) fromDescendants(child, cs, nodes);
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}
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} //-- fromDescendants
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/**
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* Determines whether this PatternExpr matches the given node within
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* the given context
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**/
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MBool LocationStep::matches(Node* node, Node* context, ContextState* cs) {
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if ( !nodeExpr ) return MB_FALSE;
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NodeSet* nodes = (NodeSet*) evaluate(context, cs);
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MBool result = nodes->contains(node);
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delete nodes;
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return result;
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} //-- matches
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/**
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* Creates a String representation of this Expr
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* @param str the destination String to append to
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* @see Expr
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**/
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void LocationStep::toString(String& str) {
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switch (axisIdentifier) {
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case ANCESTOR_AXIS :
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str.append("ancestor::");
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break;
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case ANCESTOR_OR_SELF_AXIS :
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str.append("ancestor-or-self::");
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break;
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case DESCENDANT_AXIS:
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str.append("descendant::");
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break;
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case DESCENDANT_OR_SELF_AXIS:
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str.append("descendant-or-self::");
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break;
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case FOLLOWING_AXIS :
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str.append("following::");
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break;
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case FOLLOWING_SIBLING_AXIS:
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str.append("following-sibling::");
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break;
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case NAMESPACE_AXIS:
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str.append("namespace::");
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break;
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case PARENT_AXIS :
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str.append("parent::");
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break;
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case PRECEDING_AXIS :
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str.append("preceding::");
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break;
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case PRECEDING_SIBLING_AXIS :
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str.append("preceding-sibling::");
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break;
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case SELF_AXIS :
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str.append("self::");
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break;
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default:
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break;
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}
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if ( nodeExpr ) nodeExpr->toString(str);
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else str.append("null");
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PredicateList::toString(str);
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} //-- toString
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