src/org/apache/xalan/xsltc/compiler/ParentLocationPath.java

/*
 * @(#)$Id$
 *
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001 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) 2001, Sun
 * Microsystems., http://www.sun.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 *
 */

package org.apache.xalan.xsltc.compiler;

import org.apache.xalan.xsltc.compiler.util.Type;
import de.fub.bytecode.generic.*;
import org.apache.xalan.xsltc.compiler.util.*;
import org.apache.xalan.xsltc.dom.Axis;

final class ParentLocationPath extends RelativeLocationPath {
    private Expression _step;
    private final RelativeLocationPath _path;
    private Type stype;
    private boolean _orderNodes = false;

    public ParentLocationPath(RelativeLocationPath path, Expression step) {
	_path = path;
	_step = step;
	_path.setParent(this);
	_step.setParent(this);
    }
		
    public void setAxis(int axis) {
	_path.setAxis(axis);
    }

    public RelativeLocationPath getPath() {
	return(_path);
    }

    public Expression getStep() {
	return(_step);
    }

    public void setParser(Parser parser) {
	super.setParser(parser);
	_step.setParser(parser);
	_path.setParser(parser);
    }
    
    public String toString() {
	return "ParentLocationPath(" + _path + ", " + _step + ')';
    }

    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	stype = _step.typeCheck(stable);
	_path.typeCheck(stable);

	if (descendantAxis() && _path.descendantAxis())
	    _orderNodes = true;

	return _type = Type.NodeSet;	
    }

    public boolean descendantAxis() {
	if (_step instanceof Step) {
	    return ((Step)_step).descendantAxis();
	}
	else if (_step instanceof ParentLocationPath) {
	    return ((ParentLocationPath)_step).descendantAxis();
	}
	return(false);
    }

    /*
    public void blockIteratorReset() {
	if (_path instanceof RelativeLocationPath)
	    ((RelativeLocationPath)_path).blockIteratorReset();
	if (_step instanceof Step)
	    ((Step)_step).blockIteratorReset();
    }
    */

    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();

	// Create new StepIterator
	final int initSI = cpg.addMethodref(STEP_ITERATOR_CLASS,
					    "<init>",
					    "("
					    +NODE_ITERATOR_SIG
					    +NODE_ITERATOR_SIG
					    +")V");
	il.append(new NEW(cpg.addClass(STEP_ITERATOR_CLASS)));
	il.append(DUP);

	// Compile path iterator
	_path.translate(classGen, methodGen); // iterator on stack....
	_step.translate(classGen, methodGen);


	// Initialize StepIterator with iterators from the stack
	il.append(new INVOKESPECIAL(initSI));

	/*
	 * If this pattern contains a sequence of descendant iterators we
	 * run the risk of returning the same node several times. We put
	 * a new iterator on top of the existing one to assure node order
	 * and prevent returning a single node multiple times.
	 */
	if (_orderNodes) {
	    final String params = "("+NODE_ITERATOR_SIG+"I)"+NODE_ITERATOR_SIG;
	    final int order = cpg.addInterfaceMethodref(DOM_INTF,
							"orderNodes",
							params);
	    il.append(methodGen.loadDOM());
	    il.append(SWAP);
	    il.append(methodGen.loadContextNode());
	    il.append(new INVOKEINTERFACE(order, 3));
	}
    }
}