/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */

package org.apache.xalan.xsltc.compiler;

import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.GETFIELD;
import org.apache.bcel.generic.INVOKEINTERFACE;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.PUSH;
import org.apache.bcel.generic.InstructionList;
import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
import org.apache.xalan.xsltc.compiler.util.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Morten Jorgensen
 */
final class Comment extends Instruction {

    public void parseContents(Parser parser) {
	parseChildren(parser);
    }

    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
	typeCheckContents(stable);
	return Type.String;
    }

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

        // Shortcut for literal strings
        Text rawText = null;
        if (elementCount() == 1) {
            Object content = elementAt(0);
            if (content instanceof Text) {
                rawText = (Text) content;
            }
        }

        // If the content is literal text, call comment(char[],int,int) or
        // comment(String), as appropriate.  Otherwise, use a
        // StringValueHandler to gather the textual content of the xsl:comment
        // and call comment(String) with the result.
        if (rawText != null) {
            il.append(methodGen.loadHandler());

            if (rawText.canLoadAsArrayOffsetLength()) {
                rawText.loadAsArrayOffsetLength(classGen, methodGen);
                final int comment =
                        cpg.addInterfaceMethodref(TRANSLET_OUTPUT_INTERFACE,
                                                  "comment",
                                                  "([CII)V");
                il.append(new INVOKEINTERFACE(comment, 4));
            } else {
                il.append(new PUSH(cpg, rawText.getText()));
                final int comment =
                        cpg.addInterfaceMethodref(TRANSLET_OUTPUT_INTERFACE,
                                                  "comment",
                                                  "(" + STRING_SIG + ")V");
                il.append(new INVOKEINTERFACE(comment, 2));
            }
        } else {
            // Save the current handler base on the stack
            il.append(methodGen.loadHandler());
            il.append(DUP);             // first arg to "comment" call

            // Get the translet's StringValueHandler
            il.append(classGen.loadTranslet());
            il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
                                                   "stringValueHandler",
                                                   STRING_VALUE_HANDLER_SIG)));
            il.append(DUP);
            il.append(methodGen.storeHandler());

            // translate contents with substituted handler
            translateContents(classGen, methodGen);

            // get String out of the handler
            il.append(new INVOKEVIRTUAL(cpg.addMethodref(STRING_VALUE_HANDLER,
                                                         "getValue",
                                                         "()" + STRING_SIG)));
            // call "comment"
            final int comment =
                        cpg.addInterfaceMethodref(TRANSLET_OUTPUT_INTERFACE,
                                                  "comment",
                                                  "(" + STRING_SIG + ")V");
            il.append(new INVOKEINTERFACE(comment, 2));
            // Restore old handler base from stack
            il.append(methodGen.storeHandler());
        }
    }
}
