1 /*
2 * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
3 */
4 /*
5 * Licensed to the Apache Software Foundation (ASF) under one or more
6 * contributor license agreements. See the NOTICE file distributed with
7 * this work for additional information regarding copyright ownership.
8 * The ASF licenses this file to You under the Apache License, Version 2.0
9 * (the "License"); you may not use this file except in compliance with
10 * the License. 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
18 * limitations under the License.
19 */
20
21 package com.sun.org.apache.bcel.internal.classfile;
22
23 import java.io.DataInput;
24 import java.io.DataOutputStream;
25 import java.io.IOException;
26
27 import com.sun.org.apache.bcel.internal.Const;
28
29 /**
30 * This class represents a local variable within a method. It contains its
31 * scope, name, signature and index on the method's frame.
32 *
33 * @version $Id$
34 * @see LocalVariableTable
35 * @LastModified: Jun 2019
36 */
37 public final class LocalVariable implements Cloneable, Node {
38
39 private int start_pc; // Range in which the variable is valid
40 private int length;
41 private int name_index; // Index in constant pool of variable name
42 private int signature_index; // Index of variable signature
43 private int index; /* Variable is `index'th local variable on
44 * this method's frame.
45 */
46 private ConstantPool constant_pool;
47 private int orig_index; // never changes; used to match up with LocalVariableTypeTable entries
48
49
50 /**
51 * Initialize from another object. Note that both objects use the same
52 * references (shallow copy). Use copy() for a physical copy.
53 */
54 public LocalVariable(final LocalVariable c) {
55 this(c.getStartPC(), c.getLength(), c.getNameIndex(), c.getSignatureIndex(), c.getIndex(),
56 c.getConstantPool());
57 this.orig_index = c.getOrigIndex();
58 }
59
60
61 /**
62 * Construct object from file stream.
63 * @param file Input stream
64 * @throws IOException
65 */
66 LocalVariable(final DataInput file, final ConstantPool constant_pool) throws IOException {
67 this(file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), file
68 .readUnsignedShort(), file.readUnsignedShort(), constant_pool);
69 }
70
71
72 /**
73 * @param start_pc Range in which the variable
74 * @param length ... is valid
75 * @param name_index Index in constant pool of variable name
76 * @param signature_index Index of variable's signature
77 * @param index Variable is `index'th local variable on the method's frame
78 * @param constant_pool Array of constants
79 */
80 public LocalVariable(final int start_pc, final int length, final int name_index, final int signature_index, final int index,
81 final ConstantPool constant_pool) {
82 this.start_pc = start_pc;
83 this.length = length;
84 this.name_index = name_index;
85 this.signature_index = signature_index;
86 this.index = index;
87 this.constant_pool = constant_pool;
88 this.orig_index = index;
89 }
90
91
92 /**
93 * @param start_pc Range in which the variable
94 * @param length ... is valid
95 * @param name_index Index in constant pool of variable name
96 * @param signature_index Index of variable's signature
97 * @param index Variable is `index'th local variable on the method's frame
98 * @param constant_pool Array of constants
99 * @param orig_index Variable is `index'th local variable on the method's frame prior to any changes
100 */
101 public LocalVariable(final int start_pc, final int length, final int name_index, final int signature_index, final int index,
102 final ConstantPool constant_pool, final int orig_index) {
103 this.start_pc = start_pc;
104 this.length = length;
105 this.name_index = name_index;
106 this.signature_index = signature_index;
107 this.index = index;
108 this.constant_pool = constant_pool;
109 this.orig_index = orig_index;
110 }
111
112
113 /**
114 * Called by objects that are traversing the nodes of the tree implicitely
115 * defined by the contents of a Java class. I.e., the hierarchy of methods,
116 * fields, attributes, etc. spawns a tree of objects.
117 *
118 * @param v Visitor object
119 */
120 @Override
121 public void accept( final Visitor v ) {
122 v.visitLocalVariable(this);
123 }
124
125
126 /**
127 * Dump local variable to file stream in binary format.
128 *
129 * @param file Output file stream
130 * @throws IOException
131 */
132 public final void dump( final DataOutputStream file ) throws IOException {
133 file.writeShort(start_pc);
134 file.writeShort(length);
135 file.writeShort(name_index);
136 file.writeShort(signature_index);
137 file.writeShort(index);
138 }
139
140
141 /**
142 * @return Constant pool used by this object.
143 */
144 public final ConstantPool getConstantPool() {
145 return constant_pool;
146 }
147
148
149 /**
150 * @return Variable is valid within getStartPC() .. getStartPC()+getLength()
151 */
152 public final int getLength() {
153 return length;
154 }
155
156
157 /**
158 * @return Variable name.
159 */
160 public final String getName() {
161 ConstantUtf8 c;
162 c = (ConstantUtf8) constant_pool.getConstant(name_index, Const.CONSTANT_Utf8);
163 return c.getBytes();
164 }
165
166
167 /**
168 * @return Index in constant pool of variable name.
169 */
170 public final int getNameIndex() {
171 return name_index;
172 }
173
174
175 /**
176 * @return Signature.
177 */
178 public final String getSignature() {
179 ConstantUtf8 c;
180 c = (ConstantUtf8) constant_pool.getConstant(signature_index, Const.CONSTANT_Utf8);
181 return c.getBytes();
182 }
183
184
185 /**
186 * @return Index in constant pool of variable signature.
187 */
188 public final int getSignatureIndex() {
189 return signature_index;
190 }
191
192
193 /**
194 * @return index of register where variable is stored
195 */
196 public final int getIndex() {
197 return index;
198 }
199
200
201 /**
202 * @return index of register where variable was originally stored
203 */
204 public final int getOrigIndex() {
205 return orig_index;
206 }
207
208
209 /**
210 * @return Start of range where he variable is valid
211 */
212 public final int getStartPC() {
213 return start_pc;
214 }
215
216
217 /*
218 * Helper method shared with LocalVariableTypeTable
219 */
220 final String toStringShared( final boolean typeTable ) {
221 final String name = getName();
222 final String signature = Utility.signatureToString(getSignature(), false);
223 final String label = "LocalVariable" + (typeTable ? "Types" : "" );
224 return label + "(start_pc = " + start_pc + ", length = " + length + ", index = "
225 + index + ":" + signature + " " + name + ")";
226 }
227
228
229 /**
230 * @param constant_pool Constant pool to be used for this object.
231 */
232 public final void setConstantPool( final ConstantPool constant_pool ) {
233 this.constant_pool = constant_pool;
234 }
235
236
237 /**
238 * @param length the length of this local variable
239 */
240 public final void setLength( final int length ) {
241 this.length = length;
242 }
243
244
245 /**
246 * @param name_index the index into the constant pool for the name of this variable
247 */
248 public final void setNameIndex( final int name_index ) { // TODO unused
249 this.name_index = name_index;
250 }
251
252
253 /**
254 * @param signature_index the index into the constant pool for the signature of this variable
255 */
256 public final void setSignatureIndex( final int signature_index ) { // TODO unused
257 this.signature_index = signature_index;
258 }
259
260
261 /**
262 * @param index the index in the local variable table of this variable
263 */
264 public final void setIndex( final int index ) { // TODO unused
265 this.index = index;
266 }
267
268
269 /**
270 * @param start_pc Specify range where the local variable is valid.
271 */
272 public final void setStartPC( final int start_pc ) { // TODO unused
273 this.start_pc = start_pc;
274 }
275
276
277 /**
278 * @return string representation.
279 */
280 @Override
281 public final String toString() {
282 return toStringShared(false);
283 }
284
285
286 /**
287 * @return deep copy of this object
288 */
289 public LocalVariable copy() {
290 try {
291 return (LocalVariable) clone();
292 } catch (final CloneNotSupportedException e) {
293 // TODO should this throw?
294 }
295 return null;
296 }
297 }