/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999 The Apache Software Foundation. All rights
* reserved.
*
* 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.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.xalan.transformer;
//import org.w3c.dom.Node;
//import org.w3c.dom.Text;
//import org.w3c.dom.Element;
import javax.xml.transform.TransformerException;
import org.apache.xalan.res.XSLMessages;
import org.apache.xalan.templates.Constants;
import org.apache.xalan.templates.ElemTemplate;
import org.apache.xalan.templates.ElemTemplateElement;
/**
* Class to guard against recursion getting too deep.
*/
public class StackGuard
{
/**
* Used for infinite loop check. If the value is -1, do not
* check for infinite loops. Anyone who wants to enable that
* check should change the value of this variable to be the
* level of recursion that they want to check. Be careful setting
* this variable, if the number is too low, it may report an
* infinite loop situation, when there is none.
* Post version 1.0.0, we'll make this a runtime feature.
*/
public static int m_recursionLimit = -1;
TransformerImpl m_transformer;
/**
* Get the recursion limit.
* Used for infinite loop check. If the value is -1, do not
* check for infinite loops. Anyone who wants to enable that
* check should change the value of this variable to be the
* level of recursion that they want to check. Be careful setting
* this variable, if the number is too low, it may report an
* infinite loop situation, when there is none.
* Post version 1.0.0, we'll make this a runtime feature.
*
* @return The recursion limit.
*/
public int getRecursionLimit()
{
return m_recursionLimit;
}
/**
* Set the recursion limit.
* Used for infinite loop check. If the value is -1, do not
* check for infinite loops. Anyone who wants to enable that
* check should change the value of this variable to be the
* level of recursion that they want to check. Be careful setting
* this variable, if the number is too low, it may report an
* infinite loop situation, when there is none.
* Post version 1.0.0, we'll make this a runtime feature.
*
* @param limit The recursion limit.
*/
public void setRecursionLimit(int limit)
{
m_recursionLimit = limit;
}
/**
* Constructor StackGuard
*
*
* @param xslTemplate Current template node
* @param sourceXML Source Node
*/
public StackGuard(TransformerImpl transformerImpl)
{
m_transformer = transformerImpl;
}
/**
* Overide equal method for StackGuard objects
*
*
* @param obj StackGuard object to compare
*
* @return True if the given object matches this StackGuard object
*/
public int countLikeTemplates(ElemTemplate templ, int pos)
{
ElemTemplateElement[] elems = m_transformer.getCurrentTemplateElements();
int count = 1;
for (int i = pos-1; i >= 0; i--)
{
if(elems[i] == templ)
count++;
}
return count;
}
/**
* Get the next named or match template down from and including
* the given position.
* @param pos the current index position in the stack.
* @return null if no matched or named template found, otherwise
* the next named or matched template at or below the position.
*/
private ElemTemplate getNextMatchOrNamedTemplate(int pos)
{
ElemTemplateElement[] elems = m_transformer.getCurrentTemplateElements();
for (int i = pos; i >= 0; i--)
{
ElemTemplateElement elem = elems[i];
if(null != elem)
{
if(elem.getXSLToken() == Constants.ELEMNAME_TEMPLATE)
{
return (ElemTemplate)elem;
}
}
}
return null;
}
/**
* Check if we are in an infinite loop
*
*
* @param guard Current StackGuard object (matching current template)
*
* @throws TransformerException
*/
public void checkForInfinateLoop() throws TransformerException
{
int nTemplates = m_transformer.getCurrentTemplateElementsCount();
if(nTemplates < m_recursionLimit)
return;
if(m_recursionLimit <= 0)
return; // Safety check.
// loop from the top index down to the recursion limit (I don't think
// there's any need to go below that).
for (int i = (nTemplates - 1); i >= m_recursionLimit; i--)
{
ElemTemplate template = getNextMatchOrNamedTemplate(i);
if(null == template)
break;
int loopCount = countLikeTemplates(template, i);
if (loopCount >= m_recursionLimit)
{
// throw new TransformerException("Template nesting too deep. nesting = "+loopCount+
// ", template "+((null == template.getName()) ? "name = " : "match = ")+
// ((null != template.getName()) ? template.getName().toString()
// : template.getMatch().getPatternString()));
String idIs = XSLMessages.createMessage(((null != template.getName()) ? "nameIs" : "matchPatternIs"), null);
Object[] msgArgs = new Object[]{ new Integer(loopCount), idIs,
((null != template.getName()) ? template.getName().toString()
: template.getMatch().getPatternString()) };
String msg = XSLMessages.createMessage("recursionTooDeep", msgArgs);
throw new TransformerException(msg);
}
}
}
}