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.commons.compress.archivers.zip;
020
021import java.util.zip.ZipException;
022
023import org.apache.commons.compress.utils.ByteUtils;
024
025/**
026 * If this extra field is added as the very first extra field of the archive, Solaris will consider it an executable jar file.
027 *
028 * @Immutable
029 */
030public final class JarMarker implements ZipExtraField {
031
032    static final ZipShort ID = new ZipShort(0xCAFE);
033    private static final ZipShort NULL = new ZipShort(0);
034    private static final JarMarker DEFAULT = new JarMarker();
035
036    /**
037     * Since JarMarker is stateless we can always use the same instance.
038     *
039     * @return the DEFAULT jarmaker.
040     */
041    public static JarMarker getInstance() {
042        return DEFAULT;
043    }
044
045    /** No-arg constructor */
046    public JarMarker() {
047        // empty
048    }
049
050    /**
051     * The actual data to put central directory - without Header-ID or length specifier.
052     *
053     * @return the data
054     */
055    @Override
056    public byte[] getCentralDirectoryData() {
057        return ByteUtils.EMPTY_BYTE_ARRAY;
058    }
059
060    /**
061     * Length of the extra field in the central directory - without Header-ID or length specifier.
062     *
063     * @return 0
064     */
065    @Override
066    public ZipShort getCentralDirectoryLength() {
067        return NULL;
068    }
069
070    /**
071     * The Header-ID.
072     *
073     * @return the header id
074     */
075    @Override
076    public ZipShort getHeaderId() {
077        return ID;
078    }
079
080    /**
081     * The actual data to put into local file data - without Header-ID or length specifier.
082     *
083     * @return the data
084     */
085    @Override
086    public byte[] getLocalFileDataData() {
087        return ByteUtils.EMPTY_BYTE_ARRAY;
088    }
089
090    /**
091     * Length of the extra field in the local file data - without Header-ID or length specifier.
092     *
093     * @return 0
094     */
095    @Override
096    public ZipShort getLocalFileDataLength() {
097        return NULL;
098    }
099
100    /**
101     * Doesn't do anything special since this class always uses the same data in central directory and local file data.
102     */
103    @Override
104    public void parseFromCentralDirectoryData(final byte[] buffer, final int offset, final int length) throws ZipException {
105        parseFromLocalFileData(buffer, offset, length);
106    }
107
108    /**
109     * Populate data from this array as if it was in local file data.
110     *
111     * @param data   an array of bytes
112     * @param offset the start offset
113     * @param length the number of bytes in the array from offset
114     * @throws ZipException on error
115     */
116    @Override
117    public void parseFromLocalFileData(final byte[] data, final int offset, final int length) throws ZipException {
118        if (length != 0) {
119            throw new ZipException("JarMarker doesn't expect any data");
120        }
121    }
122}