/*
* 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 org.apache.xml.dtm.DTM;
import java.io.PrintWriter;
import java.io.StringWriter;
import javax.xml.transform.TransformerException;
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;
/**
* 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;
}
/** Stylesheet Template node */
ElemTemplateElement m_xslRule;
/** Source node */
int m_sourceXML;
/** Stack where ElemTempalteElements will be pushed */
java.util.Stack stack = new java.util.Stack();
/**
* Constructor StackGuard
*
*/
public StackGuard(){}
/**
* Constructor StackGuard
*
*
* @param xslTemplate Current template node
* @param sourceXML Source Node
*/
public StackGuard(ElemTemplateElement xslTemplate, int sourceXML)
{
m_xslRule = xslTemplate;
m_sourceXML = sourceXML;
}
/**
* Overide equal method for StackGuard objects
*
*
* @param obj StackGuard object to compare
*
* @return True if the given object matches this StackGuard object
*/
public boolean equals(Object obj)
{
if (((StackGuard) obj).m_xslRule.equals(m_xslRule)
&& ((StackGuard) obj).m_sourceXML == m_sourceXML)
{
return true;
}
return false;
}
/**
* Output diagnostics if in an infinite loop
*
*
* @param pw Non-null PrintWriter instance to use
*/
public void print(PrintWriter pw)
{
// for the moment, these diagnostics are really bad...
// %DTBD% We need an execution context.
// if (m_sourceXML instanceof Text)
// {
// Text tx = (Text) m_sourceXML;
//
// pw.println(tx.getData());
// }
// else if (m_sourceXML instanceof Element)
// {
// Element elem = (Element) m_sourceXML;
//
// pw.println(elem.getNodeName());
// }
}
/**
* Check if we are in an infinite loop
*
*
* @param guard Current StackGuard object (matching current template)
*
* @throws TransformerException
*/
public void checkForInfinateLoop(StackGuard guard) throws TransformerException
{
int nRules = stack.size();
int loopCount = 0;
for (int i = (nRules - 1); i >= 0; i--)
{
if (stack.elementAt(i).equals(guard))
{
loopCount++;
}
if (loopCount >= m_recursionLimit)
{
// Print out really bad diagnostics.
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
pw.println("Infinite loop diagnosed! Stack trace:");
int k;
for (k = 0; k < nRules; k++)
{
pw.println("Source Elem #" + k + " ");
StackGuard guardOnStack = (StackGuard) stack.elementAt(i);
guardOnStack.print(pw);
}
pw.println("Source Elem #" + k + " ");
guard.print(pw);
pw.println("End of infinite loop diagnosis.");
throw new TransformerException(sw.getBuffer().toString());
}
}
}
/**
* Push in a StackGuard object mathing given template
*
*
* @param xslTemplate Current template being processed
* @param sourceXML Current Source Node
*
* @throws TransformerException
*/
public void push(ElemTemplateElement xslTemplate, int sourceXML)
throws TransformerException
{
StackGuard guard = new StackGuard(xslTemplate, sourceXML);
checkForInfinateLoop(guard);
stack.push(guard);
}
/**
* Pop out Stack of StackGuard objects
*
*/
public void pop()
{
stack.pop();
}
}