code: /*
   * 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());
          }
      }
  }
  