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5   /*
6    * Copyright 2001-2004 The Apache Software Foundation.
7    *
8    * Licensed under the Apache License, Version 2.0 (the "License");
9    * you may not use this file except in compliance with the License.
10   * You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
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19   */
20  /*
21   * $Id: ValueOf.java,v 1.2.4.1 2005/09/05 09:30:04 pvedula Exp $
22   */
23  
24  package com.sun.org.apache.xalan.internal.xsltc.compiler;
25  
26  import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
27  import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
28  import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
29  import com.sun.org.apache.bcel.internal.generic.InstructionList;
30  import com.sun.org.apache.bcel.internal.generic.PUSH;
31  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
32  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
33  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
34  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
35  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
36  import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;
37  
38  /**
39   * @author Jacek Ambroziak
40   * @author Santiago Pericas-Geertsen
41   * @author Morten Jorgensen
42   */
43  final class ValueOf extends Instruction {
44      private Expression _select;
45      private boolean _escaping = true;
46      private boolean _isString = false;
47  
48      public void display(int indent) {
49          indent(indent);
50          Util.println("ValueOf");
51          indent(indent + IndentIncrement);
52          Util.println("select " + _select.toString());
53      }
54  
55      public void parseContents(Parser parser) {
56          _select = parser.parseExpression(this, "select", null);
57  
58          // make sure required attribute(s) have been set
59          if (_select.isDummy()) {
60              reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "select");
61              return;
62          }
63          final String str = getAttribute("disable-output-escaping");
64          if ((str != null) && (str.equals("yes"))) _escaping = false;
65      }
66  
67      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
68          Type type = _select.typeCheck(stable);
69  
70          // Prefer to handle the value as a node; fall back to String, otherwise
71          if (type != null && !type.identicalTo(Type.Node)) {
72              /***
73               *** %HZ% Would like to treat result-tree fragments in the same
74               *** %HZ% way as node sets for value-of, but that's running into
75               *** %HZ% some snags.  Instead, they'll be converted to String
76              if (type.identicalTo(Type.ResultTree)) {
77                  _select = new CastExpr(new CastExpr(_select, Type.NodeSet),
78                                         Type.Node);
79              } else
80              ***/
81              if (type.identicalTo(Type.NodeSet)) {
82                  _select = new CastExpr(_select, Type.Node);
83              } else {
84                  _isString = true;
85                  if (!type.identicalTo(Type.String)) {
86                      _select = new CastExpr(_select, Type.String);
87                  }
88                  _isString = true;
89              }
90          }
91          return Type.Void;
92      }
93  
94      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
95          final ConstantPoolGen cpg = classGen.getConstantPool();
96          final InstructionList il = methodGen.getInstructionList();
97          final int setEscaping = cpg.addInterfaceMethodref(OUTPUT_HANDLER,
98                                                            "setEscaping","(Z)Z");
99  
100         // Turn off character escaping if so is wanted.
101         if (!_escaping) {
102             il.append(methodGen.loadHandler());
103             il.append(new PUSH(cpg,false));
104             il.append(new INVOKEINTERFACE(setEscaping,2));
105         }
106 
107         // Translate the contents.  If the value is a string, use the
108         // translet.characters(String, TranslatOutputHandler) method.
109         // Otherwise, the value is a node, and the
110         // dom.characters(int node, TransletOutputHandler) method can dispatch
111         // the string value of the node to the output handler more efficiently.
112         if (_isString) {
113             final int characters = cpg.addMethodref(TRANSLET_CLASS,
114                                                     CHARACTERSW,
115                                                     CHARACTERSW_SIG);
116 
117             il.append(classGen.loadTranslet());
118             _select.translate(classGen, methodGen);
119             il.append(methodGen.loadHandler());
120             il.append(new INVOKEVIRTUAL(characters));
121         } else {
122             final int characters = cpg.addInterfaceMethodref(DOM_INTF,
123                                                              CHARACTERS,
124                                                              CHARACTERS_SIG);
125 
126             il.append(methodGen.loadDOM());
127             _select.translate(classGen, methodGen);
128             il.append(methodGen.loadHandler());
129             il.append(new INVOKEINTERFACE(characters, 3));
130         }
131 
132         // Restore character escaping setting to whatever it was.
133         if (!_escaping) {
134             il.append(methodGen.loadHandler());
135             il.append(SWAP);
136             il.append(new INVOKEINTERFACE(setEscaping,2));
137             il.append(POP);
138         }
139     }
140 }