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 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 * @param nameIndex Index in constant pool to CONSTANT_Utf8, which should represent the string "SourceFile".
54 * @param length Content length in bytes, the value should be 2.
55 * @param constantPool The constant pool that this attribute is associated with.
56 * @param sourceFileIndex Index in constant pool to CONSTANT_Utf8. This string will be interpreted as the name of the
57 * file from which this class was compiled. It will not be interpreted as indicating the name of the directory
58 * contqining the file or an absolute path; this information has to be supplied the consumer of this attribute -
59 * in many cases, the JVM.
60 */
61 public SourceFile(final int nameIndex, final int length, final int sourceFileIndex, final ConstantPool constantPool) {
62 super(Const.ATTR_SOURCE_FILE, nameIndex, Args.require(length, 2, "SourceFile length attribute"), constantPool);
63 this.sourceFileIndex = Args.requireU2(sourceFileIndex, 0, constantPool.getLength(), "SourceFile source file index");
64 }
65
66 /**
67 * Initialize from another object. Note that both objects use the same references (shallow copy). Use clone() for a
68 * physical copy.
69 *
70 * @param c Source to copy.
71 */
72 public SourceFile(final SourceFile c) {
73 this(c.getNameIndex(), c.getLength(), c.getSourceFileIndex(), c.getConstantPool());
74 }
75
76 /**
77 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
78 * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
79 *
80 * @param v Visitor object
81 */
82 @Override
83 public void accept(final Visitor v) {
84 v.visitSourceFile(this);
85 }
86
87 /**
88 * @return deep copy of this attribute
89 */
90 @Override
91 public Attribute copy(final ConstantPool constantPool) {
92 return (Attribute) clone();
93 }
94
95 /**
96 * Dump source file attribute to file stream in binary format.
97 *
98 * @param file Output file stream
99 * @throws IOException if an I/O error occurs.
100 */
101 @Override
102 public void dump(final DataOutputStream file) throws IOException {
103 super.dump(file);
104 file.writeShort(sourceFileIndex);
105 }
106
107 /**
108 * @return Index in constant pool of source file name.
109 */
110 public int getSourceFileIndex() {
111 return sourceFileIndex;
112 }
113
114 /**
115 * @return Source file name.
116 */
117 public String getSourceFileName() {
118 return super.getConstantPool().getConstantUtf8(sourceFileIndex).getBytes();
119 }
120
121 /**
122 * @param sourceFileIndex
123 */
124 public void setSourceFileIndex(final int sourceFileIndex) {
125 this.sourceFileIndex = sourceFileIndex;
126 }
127
128 /**
129 * @return String representation
130 */
131 @Override
132 public String toString() {
133 return "SourceFile: " + getSourceFileName();
134 }
135 }