package net.sf.saxon.instruct;
import net.sf.saxon.Controller;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.expr.XPathContextMajor;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.NodeInfo;
import net.sf.saxon.om.StandardNames;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trace.Location;
import net.sf.saxon.trans.Mode;
import net.sf.saxon.trans.Rule;
import net.sf.saxon.trans.XPathException;
import java.util.Arrays;
/**
* An xsl:next-match element in the stylesheet
*/
public class NextMatch extends ApplyImports {
boolean useTailRecursion;
public NextMatch(boolean useTailRecursion) {
this.useTailRecursion = useTailRecursion;
}
/**
* Get the name of this instruction for diagnostic and tracing purposes
*/
public int getInstructionNameCode() {
return StandardNames.XSL_NEXT_MATCH;
}
public TailCall processLeavingTail(XPathContext context) throws XPathException {
Controller controller = context.getController();
// handle parameters if any
ParameterSet params = assembleParams(context, actualParams);
ParameterSet tunnels = assembleTunnelParams(context, tunnelParams);
Rule currentRule = context.getCurrentTemplateRule();
if (currentRule==null) {
XPathException e = new XPathException("There is no current template rule");
e.setXPathContext(context);
e.setErrorCode("XTDE0560");
throw e;
}
Mode mode = context.getCurrentMode();
if (mode == null) {
mode = controller.getRuleManager().getDefaultMode();
}
if (context.getCurrentIterator()==null) {
XPathException e = new XPathException("There is no context item");
e.setXPathContext(context);
e.setErrorCode("XTDE0565");
throw e;
}
Item currentItem = context.getCurrentIterator().current();
if (!(currentItem instanceof NodeInfo)) {
XPathException e = new XPathException("Cannot call xsl:next-match when context item is not a node");
e.setXPathContext(context);
e.setErrorCode("XTDE0565");
throw e;
}
NodeInfo node = (NodeInfo)currentItem;
Rule rule = controller.getRuleManager().getNextMatchHandler(node, mode, currentRule, context);
if (rule==null) { // use the default action for the node
ApplyTemplates.defaultAction(node, params, tunnels, context, getLocationId());
} else if (useTailRecursion) {
//Template nh = (Template)rule.getAction();
// clear all the local variables: they are no longer needed
Arrays.fill(context.getStackFrame().getStackFrameValues(), null);
return new NextMatchPackage(rule, params, tunnels, context);
} else {
Template nh = (Template)rule.getAction();
XPathContextMajor c2 = context.newContext();
c2.setOrigin(this);
c2.setOriginatingConstructType(Location.TEMPLATE);
c2.openStackFrame(nh.getStackFrameMap());
c2.setLocalParameters(params);
c2.setTunnelParameters(tunnels);
c2.setCurrentTemplateRule(rule);
nh.apply(c2);
}
return null;
}
/**
* Diagnostic print of expression structure. The abstract expression tree
* is written to the supplied output destination.
*/
public void explain(ExpressionPresenter out) {
out.startElement("nextMatch");
if (actualParams != null && actualParams.length > 0) {
out.startSubsidiaryElement("withParams");
WithParam.displayExpressions(actualParams, out);
out.endSubsidiaryElement();
}
if (tunnelParams != null && tunnelParams.length > 0) {
out.startSubsidiaryElement("tunnelParams");
WithParam.displayExpressions(tunnelParams, out);
out.endSubsidiaryElement();
}
out.endElement();
}
/**
* A NextMatchPackage is an object that encapsulates the name of a template to be called,
* the parameters to be supplied, and the execution context. This object can be returned as a tail
* call, so that the actual call is made from a lower point on the stack, allowing a tail-recursive
* template to execute in a finite stack size
*/
private class NextMatchPackage implements TailCall {
private Rule rule;
private ParameterSet params;
private ParameterSet tunnelParams;
private XPathContext evaluationContext;
/**
* Construct a NextMatchPackage that contains information about a call.
* @param rule the rule identifying the Template to be called
* @param params the parameters to be supplied to the called template
* @param tunnelParams the tunnel parameter supplied to the called template
* @param evaluationContext saved context information from the Controller (current mode, etc)
* which must be reset to ensure that the template is called with all the context information
* intact
*/
public NextMatchPackage(Rule rule,
ParameterSet params,
ParameterSet tunnelParams,
XPathContext evaluationContext) {
this.rule = rule;
this.params = params;
this.tunnelParams = tunnelParams;
this.evaluationContext = evaluationContext;
}
/**
* Process the template call encapsulated by this package.
* @return another TailCall. This will never be the original call, but it may be the next
* recursive call. For example, if A calls B which calls C which calls D, then B may return
* a TailCall to A representing the call from B to C; when this is processed, the result may be
* a TailCall representing the call from C to D.
* @throws XPathException if a dynamic error occurs
*/
public TailCall processLeavingTail() throws XPathException {
Template nh = (Template)rule.getAction();
XPathContextMajor c2 = evaluationContext.newContext();
c2.setOrigin(NextMatch.this);
c2.setOriginatingConstructType(Location.TEMPLATE);
c2.setLocalParameters(params);
c2.setTunnelParameters(tunnelParams);
c2.openStackFrame(nh.getStackFrameMap());
c2.setCurrentTemplateRule(rule);
// System.err.println("Tail call on template");
return nh.applyLeavingTail(c2);
}
}
}
//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
// you may not use this file except in compliance with the License. You may obtain a copy of the
// License at http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file.
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//