    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}