1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * https://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.bcel.classfile;
20
21 import java.io.DataInput;
22 import java.io.DataOutputStream;
23 import java.io.IOException;
24
25 import org.apache.bcel.Const;
26 import org.apache.bcel.util.Args;
27
28 /**
29 * This class is derived from <em>Attribute</em> and represents a reference to the source file of this class. At most
30 * one SourceFile attribute should appear per classfile. The intention of this class is that it is instantiated from the
31 * <em>Attribute.readAttribute()</em> method.
32 *
33 * @see Attribute
34 */
35 public final class SourceFile extends Attribute {
36
37 private int sourceFileIndex;
38
39 /**
40 * Constructs object from input stream.
41 *
42 * @param nameIndex Index in constant pool to CONSTANT_Utf8.
43 * @param length Content length in bytes.
44 * @param input Input stream.
45 * @param constantPool Array of constants.
46 * @throws IOException Thrown if an I/O error occurs.
47 */
48 SourceFile(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
49 this(nameIndex, length, input.readUnsignedShort(), constantPool);
50 }
51
52 /**
53 * Constructs a SourceFile.
54 *
55 * @param nameIndex Index in constant pool to CONSTANT_Utf8, which should represent the string "SourceFile".
56 * @param length Content length in bytes, the value should be 2.
57 * @param constantPool The constant pool that this attribute is associated with.
58 * @param sourceFileIndex Index in constant pool to CONSTANT_Utf8. This string will be interpreted as the name of the
59 * file from which this class was compiled. It will not be interpreted as indicating the name of the directory
60 * contqining the file or an absolute path; this information has to be supplied the consumer of this attribute -
61 * in many cases, the JVM.
62 */
63 public SourceFile(final int nameIndex, final int length, final int sourceFileIndex, final ConstantPool constantPool) {
64 super(Const.ATTR_SOURCE_FILE, nameIndex, Args.require(length, 2, "SourceFile length attribute"), constantPool);
65 this.sourceFileIndex = Args.requireU2(sourceFileIndex, 0, constantPool.getLength(), "SourceFile source file index");
66 }
67
68 /**
69 * Initialize from another object. Note that both objects use the same references (shallow copy). Use clone() for a
70 * physical copy.
71 *
72 * @param c Source to copy.
73 */
74 public SourceFile(final SourceFile c) {
75 this(c.getNameIndex(), c.getLength(), c.getSourceFileIndex(), c.getConstantPool());
76 }
77
78 /**
79 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
80 * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
81 *
82 * @param v Visitor object.
83 */
84 @Override
85 public void accept(final Visitor v) {
86 v.visitSourceFile(this);
87 }
88
89 /**
90 * @return deep copy of this attribute.
91 */
92 @Override
93 public Attribute copy(final ConstantPool constantPool) {
94 return (Attribute) clone();
95 }
96
97 /**
98 * Dumps source file attribute to file stream in binary format.
99 *
100 * @param file Output file stream.
101 * @throws IOException Thrown if an I/O error occurs.
102 */
103 @Override
104 public void dump(final DataOutputStream file) throws IOException {
105 super.dump(file);
106 file.writeShort(sourceFileIndex);
107 }
108
109 /**
110 * Gets the source file index.
111 *
112 * @return Index in constant pool of source file name.
113 */
114 public int getSourceFileIndex() {
115 return sourceFileIndex;
116 }
117
118 /**
119 * Gets the source file name.
120 *
121 * @return Source file name.
122 */
123 public String getSourceFileName() {
124 return super.getConstantPool().getConstantUtf8(sourceFileIndex).getBytes();
125 }
126
127 /**
128 * Sets the source file index.
129 *
130 * @param sourceFileIndex The source file index to set.
131 */
132 public void setSourceFileIndex(final int sourceFileIndex) {
133 this.sourceFileIndex = sourceFileIndex;
134 }
135
136 /**
137 * @return String representation.
138 */
139 @Override
140 public String toString() {
141 return "SourceFile: " + getSourceFileName();
142 }
143 }