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

/*
 * @(#)$Id$
 *
 * 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
 *
 */

package org.apache.xalan.xsltc.compiler;

import org.apache.bcel.generic.ALOAD;
import org.apache.bcel.generic.ASTORE;
import org.apache.bcel.generic.BranchHandle;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.IFEQ;
import org.apache.bcel.generic.IFNULL;
import org.apache.bcel.generic.ILOAD;
import org.apache.bcel.generic.INVOKEINTERFACE;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.ISTORE;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.LocalVariableGen;
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.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
import org.apache.xalan.xsltc.compiler.util.Util;

final class Copy extends Instruction {
    private UseAttributeSets _useSets;
    
    public void parseContents(Parser parser) {
	final String useSets = getAttribute("use-attribute-sets");
	if (useSets.length() > 0) {
            if (!Util.isValidQNames(useSets)) {
                ErrorMsg err = new ErrorMsg(ErrorMsg.INVALID_QNAME_ERR, useSets, this);
                parser.reportError(Constants.ERROR, err);	
            }		
	    _useSets = new UseAttributeSets(useSets, parser);
	}
	parseChildren(parser);
    }
    
    public void display(int indent) {
	indent(indent);
	Util.println("Copy");
	indent(indent + IndentIncrement);
	displayContents(indent + IndentIncrement);
    }

    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	if (_useSets != null) {
	    _useSets.typeCheck(stable);
	}
	typeCheckContents(stable);
	return Type.Void;
    }
	
    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();

	final LocalVariableGen name =
	    methodGen.addLocalVariable2("name",
					Util.getJCRefType(STRING_SIG),
					il.getEnd());
	final LocalVariableGen length =
	    methodGen.addLocalVariable2("length",
					Util.getJCRefType("I"),
					il.getEnd());

	// Get the name of the node to copy and save for later
	il.append(methodGen.loadDOM());
	il.append(methodGen.loadCurrentNode());
	il.append(methodGen.loadHandler());
	final int cpy = cpg.addInterfaceMethodref(DOM_INTF,
						  "shallowCopy",
						  "("
						  + NODE_SIG
						  + TRANSLET_OUTPUT_SIG
						  + ")" + STRING_SIG); 
	il.append(new INVOKEINTERFACE(cpy, 3));
	il.append(DUP);
	il.append(new ASTORE(name.getIndex()));
	final BranchHandle ifBlock1 = il.append(new IFNULL(null));

	// Get the length of the node name and save for later
	il.append(new ALOAD(name.getIndex()));
	final int lengthMethod = cpg.addMethodref(STRING_CLASS,"length","()I");
	il.append(new INVOKEVIRTUAL(lengthMethod));
	il.append(new ISTORE(length.getIndex()));

	// Copy in attribute sets if specified
	if (_useSets != null) {
	    // If the parent of this element will result in an element being
	    // output then we know that it is safe to copy out the attributes
	    final SyntaxTreeNode parent = getParent();
	    if ((parent instanceof LiteralElement) ||
		(parent instanceof LiteralElement)) {
		_useSets.translate(classGen, methodGen);
	    }
	    // If not we have to check to see if the copy will result in an
	    // element being output.
	    else {
		// check if element; if not skip to translate body
		il.append(new ILOAD(length.getIndex()));
		final BranchHandle ifBlock2 = il.append(new IFEQ(null));
		// length != 0 -> element -> do attribute sets
		_useSets.translate(classGen, methodGen);
		// not an element; root
		ifBlock2.setTarget(il.append(NOP));
	    }
	}

	// Instantiate body of xsl:copy
	translateContents(classGen, methodGen);

	// Call the output handler's endElement() if we copied an element
	// (The DOM.shallowCopy() method calls startElement().)
	il.append(new ILOAD(length.getIndex()));
	final BranchHandle ifBlock3 = il.append(new IFEQ(null));
	il.append(methodGen.loadHandler());
	il.append(new ALOAD(name.getIndex()));
	il.append(methodGen.endElement());
	
	final InstructionHandle end = il.append(NOP);
	ifBlock1.setTarget(end);
	ifBlock3.setTarget(end);
	methodGen.removeLocalVariable(name);
	methodGen.removeLocalVariable(length);
    }
}