    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;
    020
    021import java.io.File;
    022import java.io.IOException;
    023import java.io.OutputStream;
    024import java.nio.file.LinkOption;
    025import java.nio.file.Path;
    026
    027/**
    028 * Archive output stream implementations are expected to override the
    029 * {@link #write(byte[], int, int)} method to improve performance.
    030 * They should also override {@link #close()} to ensure that any necessary
    031 * trailers are added.
    032 *
    033 * <p>The normal sequence of calls when working with ArchiveOutputStreams is:</p>
    034 * <ul>
    035 *   <li>Create ArchiveOutputStream object,</li>
    036 *   <li>optionally write SFX header (Zip only),</li>
    037 *   <li>repeat as needed:
    038 *     <ul>
    039 *       <li>{@link #putArchiveEntry(ArchiveEntry)} (writes entry header),
    040 *       <li>{@link #write(byte[])} (writes entry data, as often as needed),
    041 *       <li>{@link #closeArchiveEntry()} (closes entry),
    042 *     </ul>
    043 *   </li>
    044 *   <li> {@link #finish()} (ends the addition of entries),</li>
    045 *   <li> optionally write additional data, provided format supports it,</li>
    046 *   <li>{@link #close()}.</li>
    047 * </ul>
    048 */
    049public abstract class ArchiveOutputStream extends OutputStream {
    050
    051    static final int BYTE_MASK = 0xFF;
    052    /** Temporary buffer used for the {@link #write(int)} method */
    053    private final byte[] oneByte = new byte[1];
    054
    055    /** holds the number of bytes written to this stream */
    056    private long bytesWritten;
    057    // Methods specific to ArchiveOutputStream
    058
    059    /**
    060     * Whether this stream is able to write the given entry.
    061     *
    062     * <p>Some archive formats support variants or details that are
    063     * not supported (yet).</p>
    064     *
    065     * @param archiveEntry
    066     *            the entry to test
    067     * @return This implementation always returns true.
    068     * @since 1.1
    069     */
    070    public boolean canWriteEntryData(final ArchiveEntry archiveEntry) {
    071        return true;
    072    }
    073
    074    /**
    075     * Closes the archive entry, writing any trailer information that may
    076     * be required.
    077     * @throws IOException if an I/O error occurs
    078     */
    079    public abstract void closeArchiveEntry() throws IOException;
    080
    081    /**
    082     * Increments the counter of already written bytes.
    083     * Doesn't increment if EOF has been hit ({@code written == -1}).
    084     *
    085     * @param written the number of bytes written
    086     */
    087    protected void count(final int written) {
    088        count((long) written);
    089    }
    090
    091    /**
    092     * Increments the counter of already written bytes.
    093     * Doesn't increment if EOF has been hit ({@code written == -1}).
    094     *
    095     * @param written the number of bytes written
    096     * @since 1.1
    097     */
    098    protected void count(final long written) {
    099        if (written != -1) {
    100            bytesWritten = bytesWritten + written;
    101        }
    102    }
    103
    104    /**
    105     * Create an archive entry using the inputFile and entryName provided.
    106     *
    107     * @param inputFile the file to create the entry from
    108     * @param entryName name to use for the entry
    109     * @return the ArchiveEntry set up with details from the file
    110     *
    111     * @throws IOException if an I/O error occurs
    112     */
    113    public abstract ArchiveEntry createArchiveEntry(File inputFile, String entryName) throws IOException;
    114
    115    // Generic implementations of OutputStream methods that may be useful to sub-classes
    116
    117    /**
    118     * Create an archive entry using the inputPath and entryName provided.
    119     *
    120     * The default implementation calls simply delegates as:
    121     * <pre>return createArchiveEntry(inputFile.toFile(), entryName);</pre>
    122     *
    123     * Subclasses should override this method.
    124     *
    125     * @param inputPath the file to create the entry from
    126     * @param entryName name to use for the entry
    127     * @param options options indicating how symbolic links are handled.
    128     * @return the ArchiveEntry set up with details from the file
    129     *
    130     * @throws IOException if an I/O error occurs
    131     * @since 1.21
    132     */
    133    public ArchiveEntry createArchiveEntry(final Path inputPath, final String entryName, final LinkOption... options) throws IOException {
    134        return createArchiveEntry(inputPath.toFile(), entryName);
    135    }
    136
    137    /**
    138     * Finishes the addition of entries to this stream, without closing it.
    139     * Additional data can be written, if the format supports it.
    140     *
    141     * @throws IOException if the user forgets to close the entry.
    142     */
    143    public abstract void finish() throws IOException;
    144
    145    /**
    146     * Returns the current number of bytes written to this stream.
    147     * @return the number of written bytes
    148     * @since 1.1
    149     */
    150    public long getBytesWritten() {
    151        return bytesWritten;
    152    }
    153
    154    /**
    155     * Returns the current number of bytes written to this stream.
    156     * @return the number of written bytes
    157     * @deprecated this method may yield wrong results for large
    158     * archives, use #getBytesWritten instead
    159     */
    160    @Deprecated
    161    public int getCount() {
    162        return (int) bytesWritten;
    163    }
    164
    165    /**
    166     * Writes the headers for an archive entry to the output stream.
    167     * The caller must then write the content to the stream and call
    168     * {@link #closeArchiveEntry()} to complete the process.
    169     *
    170     * @param entry describes the entry
    171     * @throws IOException if an I/O error occurs
    172     */
    173    public abstract void putArchiveEntry(ArchiveEntry entry) throws IOException;
    174
    175    /**
    176     * Writes a byte to the current archive entry.
    177     *
    178     * <p>This method simply calls {@code write( byte[], 0, 1 )}.
    179     *
    180     * <p>MUST be overridden if the {@link #write(byte[], int, int)} method
    181     * is not overridden; may be overridden otherwise.
    182     *
    183     * @param b The byte to be written.
    184     * @throws IOException on error
    185     */
    186    @Override
    187    public void write(final int b) throws IOException {
    188        oneByte[0] = (byte) (b & BYTE_MASK);
    189        write(oneByte, 0, 1);
    190    }
    191}