/*
 * @(#)$Id$
 *
 * 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
 * @author Morten Jorgensen
 *
 */

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.*;

final class VariableRef extends Expression {
    private final Variable _variable;
    private boolean _escaped;
	
    public VariableRef(Variable variable) {
	_variable = variable;
	variable.addReference(this);
    }

    public Variable getVariable() {
	return(_variable);
    }

    public String toString() {
	return "variable-ref(" + _variable.getName() + ')';
    }

    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	if (_variable.isLocal()) {
	    if (_escaped = isEscaped()) {
		_variable.setEscapes();
	    }
	    else {
		_variable.setUsedLocally();
	    }
	}
	return _type = _variable.getType();
    }

    private boolean isEscaped() {
	final SyntaxTreeNode limit = _variable.getParent();
	SyntaxTreeNode parent = getParent();
	do {
	    if (parent.isClosureBoundary()) {
		return true;
	    }
	    else {
		parent = parent.getParent();
	    }
	}
	while (parent != limit);
	return limit.isClosureBoundary();
    }

    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();
		
	final Type varType = _variable.getType();
	final String varName = _variable.getName().getLocalPart();

	if (_variable.isLocal()) {
	    if (varType.implementedAsMethod() == false) {
		if (classGen.isExternal() || _escaped) {
		    il.append(classGen.loadTranslet());
		    il.append(new PUSH(cpg, _variable.getStackIndex()));
		    final int getVar = cpg.addMethodref(TRANSLET_CLASS, 
							GET_VARIABLE,
							GET_VARIABLE_SIG);
		    il.append(new INVOKEVIRTUAL(getVar));
		    _type.translateUnBox(classGen, methodGen);
		}
		else {
		     il.append(_variable.loadInstruction());
		    _variable.removeReference(this, methodGen);
		}
	    }
	    else {
		// falls through -> result trees + variables
	    }
	}
	else {
	    if (varType.implementedAsMethod() == false) {
		final String className = classGen.getClassName();
		String signature = varType.toSignature();
		if (signature.equals(DOM_IMPL_SIG))
		    signature = classGen.getDOMClassSig();
		
		il.append(classGen.loadTranslet());
		
		// If inside a predicate we must cast this ref down
		if (classGen.isExternal()) {
		    il.append(new CHECKCAST(cpg.addClass(className)));
		}
		il.append(new GETFIELD(cpg.addFieldref(className,
						       varName, signature)));
	    }
	    else {
		// falls through -> result trees + variables
	    }
	}
    }
}