    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 * <p>
    034 * Each AR archive starts with "!&lt;arch&gt;" followed by a LF. After these 8 bytes the archive entries are listed. The format of an entry header is as it
    035 * follows:
    036 * </p>
    037 *
    038 * <pre>
    039 * START BYTE   END BYTE    NAME                    FORMAT      LENGTH
    040 * 0            15          File name               ASCII       16
    041 * 16           27          Modification timestamp  Decimal     12
    042 * 28           33          Owner ID                Decimal     6
    043 * 34           39          Group ID                Decimal     6
    044 * 40           47          File mode               Octal       8
    045 * 48           57          File size (bytes)       Decimal     10
    046 * 58           59          File magic              \140\012    2
    047 * </pre>
    048 * <p>
    049 * This specifies that an ar archive entry header contains 60 bytes.
    050 * </p>
    051 * <p>
    052 * Due to the limitation of the file name length to 16 bytes GNU and BSD has their own variants of this format. Currently Commons Compress can read but not
    053 * write the GNU variant. It fully supports the BSD variant.
    054 * </p>
    055 *
    056 * @see <a href="https://www.freebsd.org/cgi/man.cgi?query=ar&sektion=5">ar man page</a>
    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    /**
    070     * SVR4/GNU adds a trailing / to names; BSD does not. They also vary in how names longer than 16 characters are represented. (Not yet fully supported by
    071     * 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     *
    083     * @param inputFile the file to create an entry from
    084     * @param entryName the name of the entry
    085     */
    086    public ArArchiveEntry(final File inputFile, final String entryName) {
    087        // TODO sort out mode
    088        this(entryName, inputFile.isFile() ? inputFile.length() : 0, 0, 0, DEFAULT_MODE, inputFile.lastModified() / 1000);
    089    }
    090
    091    /**
    092     * Creates a new instance using the attributes of the given file
    093     *
    094     * @param inputPath the file to create an entry from
    095     * @param entryName the name of the entry
    096     * @param options   options indicating how symbolic links are handled.
    097     * @throws IOException if an I/O error occurs.
    098     * @since 1.21
    099     */
    100    public ArArchiveEntry(final Path inputPath, final String entryName, final LinkOption... options) throws IOException {
    101        this(entryName, Files.isRegularFile(inputPath, options) ? Files.size(inputPath) : 0, 0, 0, DEFAULT_MODE,
    102                Files.getLastModifiedTime(inputPath, options).toMillis() / 1000);
    103    }
    104
    105    /**
    106     * Constructs a new instance using a couple of default values.
    107     *
    108     * <p>
    109     * Sets userId and groupId to 0, the octal file mode to 644 and the last modified time to the current time.
    110     * </p>
    111     *
    112     * @param name   name of the entry
    113     * @param length length of the entry in bytes
    114     */
    115    public ArArchiveEntry(final String name, final long length) {
    116        this(name, length, 0, 0, DEFAULT_MODE, System.currentTimeMillis() / 1000);
    117    }
    118
    119    /**
    120     * Constructs a new instance.
    121     *
    122     * @param name         name of the entry
    123     * @param length       length of the entry in bytes
    124     * @param userId       numeric user id
    125     * @param groupId      numeric group id
    126     * @param mode         file mode
    127     * @param lastModified last modified time in seconds since the epoch
    128     */
    129    public ArArchiveEntry(final String name, final long length, final int userId, final int groupId, 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    /**
    157     * Gets the group ID.
    158     *
    159     * @return the group ID.
    160     */
    161    public int getGroupId() {
    162        return groupId;
    163    }
    164
    165    /**
    166     * Gets the last modified time in seconds since the epoch.
    167     *
    168     * @return the last modified date.
    169     */
    170    public long getLastModified() {
    171        return lastModified;
    172    }
    173
    174    @Override
    175    public Date getLastModifiedDate() {
    176        return new Date(1000 * getLastModified());
    177    }
    178
    179    /**
    180     * Gets the length.
    181     *
    182     * @return the length.
    183     */
    184    public long getLength() {
    185        return length;
    186    }
    187
    188    /**
    189     * Gets the mode.
    190     *
    191     * @return the mode.
    192     */
    193    public int getMode() {
    194        return mode;
    195    }
    196
    197    @Override
    198    public String getName() {
    199        return name;
    200    }
    201
    202    @Override
    203    public long getSize() {
    204        return this.getLength();
    205    }
    206
    207    /**
    208     * Gets the user ID.
    209     *
    210     * @return the user ID.
    211     */
    212    public int getUserId() {
    213        return userId;
    214    }
    215
    216    @Override
    217    public int hashCode() {
    218        return Objects.hash(name);
    219    }
    220
    221    @Override
    222    public boolean isDirectory() {
    223        return false;
    224    }
    225}