1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 package com.sun.org.apache.bcel.internal.generic;
6
7 /* ====================================================================
8 * The Apache Software License, Version 1.1
9 *
10 * Copyright (c) 2001 The Apache Software Foundation. All rights
11 * reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 *
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in
22 * the documentation and/or other materials provided with the
23 * distribution.
24 *
25 * 3. The end-user documentation included with the redistribution,
26 * if any, must include the following acknowledgment:
27 * "This product includes software developed by the
28 * Apache Software Foundation (http://www.apache.org/)."
29 * Alternately, this acknowledgment may appear in the software itself,
30 * if and wherever such third-party acknowledgments normally appear.
31 *
32 * 4. The names "Apache" and "Apache Software Foundation" and
33 * "Apache BCEL" must not be used to endorse or promote products
34 * derived from this software without prior written permission. For
35 * written permission, please contact apache@apache.org.
36 *
37 * 5. Products derived from this software may not be called "Apache",
38 * "Apache BCEL", nor may "Apache" appear in their name, without
39 * prior written permission of the Apache Software Foundation.
40 *
41 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52 * SUCH DAMAGE.
53 * ====================================================================
54 *
55 * This software consists of voluntary contributions made by many
56 * individuals on behalf of the Apache Software Foundation. For more
57 * information on the Apache Software Foundation, please see
58 * <http://www.apache.org/>.
59 */
60
61 import com.sun.org.apache.bcel.internal.Constants;
62 import com.sun.org.apache.bcel.internal.classfile.*;
63
64 /**
65 * This class represents a local variable within a method. It contains its
66 * scope, name and type. The generated LocalVariable object can be obtained
67 * with getLocalVariable which needs the instruction list and the constant
68 * pool as parameters.
69 *
70 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
71 * @see LocalVariable
72 * @see MethodGen
73 */
74 public class LocalVariableGen
75 implements InstructionTargeter, NamedAndTyped, Cloneable,
76 java.io.Serializable
77 {
78 private int index;
79 private String name;
80 private Type type;
81 private InstructionHandle start, end;
82
83 /**
84 * Generate a local variable that with index `index'. Note that double and long
85 * variables need two indexs. Index indices have to be provided by the user.
86 *
87 * @param index index of local variable
88 * @param name its name
89 * @param type its type
90 * @param start from where the instruction is valid (null means from the start)
91 * @param end until where the instruction is valid (null means to the end)
92 */
93 public LocalVariableGen(int index, String name, Type type,
94 InstructionHandle start, InstructionHandle end) {
95 if((index < 0) || (index > Constants.MAX_SHORT))
96 throw new ClassGenException("Invalid index index: " + index);
97
98 this.name = name;
99 this.type = type;
100 this.index = index;
101 setStart(start);
102 setEnd(end);
103 }
104
105 /**
106 * Get LocalVariable object.
107 *
108 * This relies on that the instruction list has already been dumped to byte code or
109 * or that the `setPositions' methods has been called for the instruction list.
110 *
111 * Note that for local variables whose scope end at the last
112 * instruction of the method's code, the JVM specification is ambiguous:
113 * both a start_pc+length ending at the last instruction and
114 * start_pc+length ending at first index beyond the end of the code are
115 * valid.
116 *
117 * @param il instruction list (byte code) which this variable belongs to
118 * @param cp constant pool
119 */
120 public LocalVariable getLocalVariable(ConstantPoolGen cp) {
121 int start_pc = start.getPosition();
122 int length = end.getPosition() - start_pc;
123
124 if(length > 0)
125 length += end.getInstruction().getLength();
126
127 int name_index = cp.addUtf8(name);
128 int signature_index = cp.addUtf8(type.getSignature());
129
130 return new LocalVariable(start_pc, length, name_index,
131 signature_index, index, cp.getConstantPool());
132 }
133
134 public void setIndex(int index) { this.index = index; }
135 public int getIndex() { return index; }
136 public void setName(String name) { this.name = name; }
137 public String getName() { return name; }
138 public void setType(Type type) { this.type = type; }
139 public Type getType() { return type; }
140
141 public InstructionHandle getStart() { return start; }
142 public InstructionHandle getEnd() { return end; }
143
144 public void setStart(InstructionHandle start) {
145 BranchInstruction.notifyTarget(this.start, start, this);
146 this.start = start;
147 }
148
149 public void setEnd(InstructionHandle end) {
150 BranchInstruction.notifyTarget(this.end, end, this);
151 this.end = end;
152 }
153
154 /**
155 * @param old_ih old target, either start or end
156 * @param new_ih new target
157 */
158 public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih) {
159 boolean targeted = false;
160
161 if(start == old_ih) {
162 targeted = true;
163 setStart(new_ih);
164 }
165
166 if(end == old_ih) {
167 targeted = true;
168 setEnd(new_ih);
169 }
170
171 if(!targeted)
172 throw new ClassGenException("Not targeting " + old_ih + ", but {" + start + ", " +
173 end + "}");
174 }
175
176 /**
177 * @return true, if ih is target of this variable
178 */
179 public boolean containsTarget(InstructionHandle ih) {
180 return (start == ih) || (end == ih);
181 }
182
183 /**
184 * We consider to local variables to be equal, if the use the same index and
185 * are valid in the same range.
186 */
187 public boolean equals(Object o) {
188 if(!(o instanceof LocalVariableGen))
189 return false;
190
191 LocalVariableGen l = (LocalVariableGen)o;
192 return (l.index == index) && (l.start == start) && (l.end == end);
193 }
194
195 public String toString() {
196 return "LocalVariableGen(" + name + ", " + type + ", " + start + ", " + end + ")";
197 }
198
199 public Object clone() {
200 try {
201 return super.clone();
202 } catch(CloneNotSupportedException e) {
203 System.err.println(e);
204 return null;
205 }
206 }
207 }