001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.bcel.classfile;
020
021import java.io.DataInput;
022import java.io.DataOutputStream;
023import java.io.IOException;
024
025import org.apache.bcel.Const;
026import org.apache.bcel.util.Args;
027
028/**
029 * This class is derived from <em>Attribute</em> and represents a reference to the source file of this class. At most
030 * one SourceFile attribute should appear per classfile. The intention of this class is that it is instantiated from the
031 * <em>Attribute.readAttribute()</em> method.
032 *
033 * @see Attribute
034 */
035public final class SourceFile extends Attribute {
036
037    private int sourceFileIndex;
038
039    /**
040     * Constructs object from input stream.
041     *
042     * @param nameIndex Index in constant pool to CONSTANT_Utf8
043     * @param length Content length in bytes
044     * @param input Input stream
045     * @param constantPool Array of constants
046     * @throws IOException if an I/O error occurs.
047     */
048    SourceFile(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
049        this(nameIndex, length, input.readUnsignedShort(), constantPool);
050    }
051
052    /**
053     * @param nameIndex Index in constant pool to CONSTANT_Utf8, which should represent the string "SourceFile".
054     * @param length Content length in bytes, the value should be 2.
055     * @param constantPool The constant pool that this attribute is associated with.
056     * @param sourceFileIndex Index in constant pool to CONSTANT_Utf8. This string will be interpreted as the name of the
057     *        file from which this class was compiled. It will not be interpreted as indicating the name of the directory
058     *        contqining the file or an absolute path; this information has to be supplied the consumer of this attribute -
059     *        in many cases, the JVM.
060     */
061    public SourceFile(final int nameIndex, final int length, final int sourceFileIndex, final ConstantPool constantPool) {
062        super(Const.ATTR_SOURCE_FILE, nameIndex, Args.require(length, 2, "SourceFile length attribute"), constantPool);
063        this.sourceFileIndex = Args.requireU2(sourceFileIndex, 0, constantPool.getLength(), "SourceFile source file index");
064    }
065
066    /**
067     * Initialize from another object. Note that both objects use the same references (shallow copy). Use clone() for a
068     * physical copy.
069     *
070     * @param c Source to copy.
071     */
072    public SourceFile(final SourceFile c) {
073        this(c.getNameIndex(), c.getLength(), c.getSourceFileIndex(), c.getConstantPool());
074    }
075
076    /**
077     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
078     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
079     *
080     * @param v Visitor object
081     */
082    @Override
083    public void accept(final Visitor v) {
084        v.visitSourceFile(this);
085    }
086
087    /**
088     * @return deep copy of this attribute
089     */
090    @Override
091    public Attribute copy(final ConstantPool constantPool) {
092        return (Attribute) clone();
093    }
094
095    /**
096     * Dump source file attribute to file stream in binary format.
097     *
098     * @param file Output file stream
099     * @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}