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.INVOKEINTERFACE;
  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.Type;
  import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
  import org.apache.xalan.xsltc.compiler.util.Util;
  
  /**
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   * @author Morten Jorgensen
   */
  final class ValueOf extends Instruction {
      private Expression _select;
      private boolean _escaping = true;
      private boolean _isString = false;
  
      public void display(int indent) {
          indent(indent);
          Util.println("ValueOf");
          indent(indent + IndentIncrement);
          Util.println("select " + _select.toString());
      }
  
      public void parseContents(Parser parser) {
          _select = parser.parseExpression(this, "select", null);
  
          // make sure required attribute(s) have been set
          if (_select.isDummy()) {
              reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "select");
              return;
          }
          final String str = getAttribute("disable-output-escaping");
          if ((str != null) && (str.equals("yes"))) _escaping = false;
      }
  
      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
          Type type = _select.typeCheck(stable);
  
          // Prefer to handle the value as a node; fall back to String, otherwise
          if (type != null && !type.identicalTo(Type.Node)) {
              /***
               *** %HZ% Would like to treat result-tree fragments in the same
               *** %HZ% way as node sets for value-of, but that's running into
               *** %HZ% some snags.  Instead, they'll be converted to String
              if (type.identicalTo(Type.ResultTree)) {
                  _select = new CastExpr(new CastExpr(_select, Type.NodeSet),
                                         Type.Node);
              } else
              ***/
              if (type.identicalTo(Type.NodeSet)) {
                  _select = new CastExpr(_select, Type.Node);
              } else {
                  _isString = true;
                  if (!type.identicalTo(Type.String)) {
                      _select = new CastExpr(_select, Type.String);
                  }
                  _isString = true;
              }
          }
          return Type.Void;
      }
  
      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
          final ConstantPoolGen cpg = classGen.getConstantPool();
          final InstructionList il = methodGen.getInstructionList();
          final int setEscaping = cpg.addInterfaceMethodref(OUTPUT_HANDLER,
                                                            "setEscaping","(Z)Z");
  
          // Turn off character escaping if so is wanted.
          if (!_escaping) {
              il.append(methodGen.loadHandler());
              il.append(new PUSH(cpg,false));
              il.append(new INVOKEINTERFACE(setEscaping,2));
          }
  
          // Translate the contents.  If the value is a string, use the
          // translet.characters(String, TranslatOutputHandler) method.
          // Otherwise, the value is a node, and the
          // dom.characters(int node, TransletOutputHandler) method can dispatch
          // the string value of the node to the output handler more efficiently.
          if (_isString) {
              final int characters = cpg.addMethodref(TRANSLET_CLASS,
                                                      CHARACTERSW,
                                                      CHARACTERSW_SIG);
  
              il.append(classGen.loadTranslet());
              _select.translate(classGen, methodGen);
              il.append(methodGen.loadHandler());
              il.append(new INVOKEVIRTUAL(characters));
          } else {
              final int characters = cpg.addInterfaceMethodref(DOM_INTF,
                                                               CHARACTERS,
                                                               CHARACTERS_SIG);
  
              il.append(methodGen.loadDOM());
              _select.translate(classGen, methodGen);
              il.append(methodGen.loadHandler());
              il.append(new INVOKEINTERFACE(characters, 3));
          }
  
          // Restore character escaping setting to whatever it was.
          if (!_escaping) {
              il.append(methodGen.loadHandler());
              il.append(SWAP);
              il.append(new INVOKEINTERFACE(setEscaping,2));
              il.append(POP);
          }
      }
  }
  