/*
 * @(#)$Id$
 *
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001-2003 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
 * @author Morten Jorgensen
 * @author John Howard <JohnH@schemasoft.com>
 *
 */

package org.apache.xalan.xsltc.compiler;

import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.PUSH;
import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
import org.apache.xalan.xsltc.compiler.util.ErrorMsg;
import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
import org.apache.xalan.xsltc.compiler.util.ReferenceType;
import org.apache.xalan.xsltc.compiler.util.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
import org.apache.xalan.xsltc.compiler.util.Util;

final class WithParam extends Instruction {

    private QName _name;
    private Expression _select;

    // %OPT% This is set to true when the WithParam is used in a
    // CallTemplate for a simple named template. If this is true,
    // the parameters are passed to the named template through method
    // arguments rather than using the expensive Translet.addParameter()
    // call.
    private boolean _doParameterOptimization = false;

    /**
     * Displays the contents of this element
     */
    public void display(int indent) {
	indent(indent);
	Util.println("with-param " + _name);
	if (_select != null) {
	    indent(indent + IndentIncrement);
	    Util.println("select " + _select.toString());
	}
	displayContents(indent + IndentIncrement);
    }
    
    /**
     * Return the name of this WithParam.
     */
    public QName getName() {
        return _name;	
    }
    
    /**
     * Set the do parameter optimization flag
     */
    public void setDoParameterOptimization(boolean flag) {
    	_doParameterOptimization = flag;
    }
    

    /**
     * The contents of a <xsl:with-param> elements are either in the element's
     * 'select' attribute (this has precedence) or in the element body.
     */
    public void parseContents(Parser parser) {
	final String name = getAttribute("name");
	if (name.length() > 0) {
	    _name = parser.getQName(name);
	}
        else {
	    reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "name");
        }
	
	final String select = getAttribute("select");
	if (select.length() > 0) {
	    _select = parser.parseExpression(this, "select", null);
	}
	
	parseChildren(parser);
    }

    /**
     * Type-check either the select attribute or the element body, depending
     * on which is in use.
     */
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	if (_select != null) {
	    final Type tselect = _select.typeCheck(stable);
	    if (tselect instanceof ReferenceType == false) {
		_select = new CastExpr(_select, Type.Reference);
	    }
	}
	else {
	    typeCheckContents(stable);
	}
	return Type.Void;
    }

    /**
     * Compile the value of the parameter, which is either in an expression in
     * a 'select' attribute, or in the with-param element's body
     */
    public void translateValue(ClassGenerator classGen,
			       MethodGenerator methodGen) {
	// Compile expression is 'select' attribute if present
	if (_select != null) {
	    _select.translate(classGen, methodGen);
	    _select.startResetIterator(classGen, methodGen);
	}
	// If not, compile result tree from parameter body if present.
	else if (hasContents()) {
	    compileResultTree(classGen, methodGen);
	}
	// If neither are present then store empty string in parameter slot
	else {
	    final ConstantPoolGen cpg = classGen.getConstantPool();
	    final InstructionList il = methodGen.getInstructionList();
	    il.append(new PUSH(cpg, Constants.EMPTYSTRING));
	}
    }

    /**
     * This code generates a sequence of bytecodes that call the
     * addParameter() method in AbstractTranslet. The method call will add
     * (or update) the parameter frame with the new parameter value.
     */
    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();

	// Translate the value and put it on the stack
	if (_doParameterOptimization) {
	    translateValue(classGen, methodGen);
	    return;
	}
	
	// Make name acceptable for use as field name in class
	String name = Util.escape(_name.getLocalPart());

	// Load reference to the translet (method is in AbstractTranslet)
	il.append(classGen.loadTranslet());

	// Load the name of the parameter
	il.append(new PUSH(cpg, name)); // TODO: namespace ?
	// Generete the value of the parameter (use value in 'select' by def.)
	translateValue(classGen, methodGen);
	// Mark this parameter value is not being the default value
	il.append(new PUSH(cpg, false));
	// Pass the parameter to the template
	il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,
						     ADD_PARAMETER,
						     ADD_PARAMETER_SIG)));
	il.append(POP); // cleanup stack
    }
}