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 * http://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.ar;
020
021import java.io.File;
022import java.io.IOException;
023import java.nio.file.Files;
024import java.nio.file.LinkOption;
025import java.nio.file.Path;
026import java.util.Date;
027import java.util.Objects;
028
029import org.apache.commons.compress.archivers.ArchiveEntry;
030
031/**
032 * Represents an archive entry in the "ar" format.
033 *
034 * Each AR archive starts with "!<arch>" followed by a LF. After these 8 bytes
035 * the archive entries are listed. The format of an entry header is as it follows:
036 *
037 * <pre>
038 * START BYTE   END BYTE    NAME                    FORMAT      LENGTH
039 * 0            15          File name               ASCII       16
040 * 16           27          Modification timestamp  Decimal     12
041 * 28           33          Owner ID                Decimal     6
042 * 34           39          Group ID                Decimal     6
043 * 40           47          File mode               Octal       8
044 * 48           57          File size (bytes)       Decimal     10
045 * 58           59          File magic              \140\012    2
046 * </pre>
047 *
048 * This specifies that an ar archive entry header contains 60 bytes.
049 *
050 * Due to the limitation of the file name length to 16 bytes GNU and
051 * BSD has their own variants of this format. Currently Commons
052 * Compress can read but not write the GNU variant.  It fully supports
053 * the BSD variant.
054 *
055 * @see <a href="https://www.freebsd.org/cgi/man.cgi?query=ar&sektion=5">ar man page</a>
056 *
057 * @Immutable
058 */
059public class ArArchiveEntry implements ArchiveEntry {
060
061    /** The header for each entry */
062    public static final String HEADER = "!<arch>\n";
063
064    /** The trailer for each entry */
065    public static final String TRAILER = "`\012";
066
067    private static final int DEFAULT_MODE = 33188; // = (octal) 0100644
068    /**
069     * SVR4/GNU adds a trailing / to names; BSD does not.
070     * They also vary in how names longer than 16 characters are represented.
071     * (Not yet fully supported by this implementation)
072     */
073    private final String name;
074    private final int userId;
075    private final int groupId;
076    private final int mode;
077    private final long lastModified;
078    private final long length;
079
080    /**
081     * Creates a new instance using the attributes of the given file
082     * @param inputFile the file to create an entry from
083     * @param entryName the name of the entry
084     */
085    public ArArchiveEntry(final File inputFile, final String entryName) {
086        // TODO sort out mode
087        this(entryName, inputFile.isFile() ? inputFile.length() : 0,
088             0, 0, DEFAULT_MODE, inputFile.lastModified() / 1000);
089    }
090
091    /**
092     * Creates a new instance using the attributes of the given file
093     * @param inputPath the file to create an entry from
094     * @param entryName the name of the entry
095     * @param options options indicating how symbolic links are handled.
096     * @throws IOException if an I/O error occurs.
097     * @since 1.21
098     */
099    public ArArchiveEntry(final Path inputPath, final String entryName, final LinkOption... options) throws IOException {
100        this(entryName, Files.isRegularFile(inputPath, options) ? Files.size(inputPath) : 0, 0, 0, DEFAULT_MODE,
101            Files.getLastModifiedTime(inputPath, options).toMillis() / 1000);
102    }
103
104    /**
105     * Create a new instance using a couple of default values.
106     *
107     * <p>Sets userId and groupId to 0, the octal file mode to 644 and
108     * the last modified time to the current time.</p>
109     *
110     * @param name name of the entry
111     * @param length length of the entry in bytes
112     */
113    public ArArchiveEntry(final String name, final long length) {
114        this(name, length, 0, 0, DEFAULT_MODE,
115             System.currentTimeMillis() / 1000);
116    }
117
118    /**
119     * Create a new instance.
120     *
121     * @param name name of the entry
122     * @param length length of the entry in bytes
123     * @param userId numeric user id
124     * @param groupId numeric group id
125     * @param mode file mode
126     * @param lastModified last modified time in seconds since the epoch
127     */
128    public ArArchiveEntry(final String name, final long length, final int userId, final int groupId,
129                          final int mode, final long lastModified) {
130        this.name = name;
131        if (length < 0) {
132            throw new IllegalArgumentException("length must not be negative");
133        }
134        this.length = length;
135        this.userId = userId;
136        this.groupId = groupId;
137        this.mode = mode;
138        this.lastModified = lastModified;
139    }
140
141    @Override
142    public boolean equals(final Object obj) {
143        if (this == obj) {
144            return true;
145        }
146        if (obj == null || getClass() != obj.getClass()) {
147            return false;
148        }
149        final ArArchiveEntry other = (ArArchiveEntry) obj;
150        if (name == null) {
151            return other.name == null;
152        }
153        return name.equals(other.name);
154    }
155
156    public int getGroupId() {
157        return groupId;
158    }
159
160    /**
161     * Last modified time in seconds since the epoch.
162     * @return the last modified date
163     */
164    public long getLastModified() {
165        return lastModified;
166    }
167
168    @Override
169    public Date getLastModifiedDate() {
170        return new Date(1000 * getLastModified());
171    }
172
173    public long getLength() {
174        return length;
175    }
176
177    public int getMode() {
178        return mode;
179    }
180
181    @Override
182    public String getName() {
183        return name;
184    }
185
186    @Override
187    public long getSize() {
188        return this.getLength();
189    }
190
191    public int getUserId() {
192        return userId;
193    }
194
195    @Override
196    public int hashCode() {
197        return Objects.hash(name);
198    }
199
200    @Override
201    public boolean isDirectory() {
202        return false;
203    }
204}