PackedObjectInfo.java

/*
 * Copyright (C) 2008-2009, Robin Rosenberg <robin.rosenberg@dewire.com>
 * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
 * and other copyright owners as documented in the project's IP log.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Distribution License v1.0 which
 * accompanies this distribution, is reproduced below, and is
 * available at http://www.eclipse.org/org/documents/edl-v10.php
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 * - Neither the name of the Eclipse Foundation, Inc. nor the
 *   names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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package org.eclipse.jgit.transport;

import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.ObjectIdOwnerMap;

/**
 * Description of an object stored in a pack file, including offset.
 * <p>
 * When objects are stored in packs Git needs the ObjectId and the offset
 * (starting position of the object data) to perform random-access reads of
 * objects from the pack. This extension of ObjectId includes the offset.
 */
public class PackedObjectInfo extends ObjectIdOwnerMap.Entry {
    private long offset;

    private int crc;

    private int type = Constants.OBJ_BAD;

    PackedObjectInfo(final long headerOffset, final int packedCRC,
            final AnyObjectId id) {
        super(id);
        offset = headerOffset;
        crc = packedCRC;
    }

    /**
     * Create a new structure to remember information about an object.
     *
     * @param id
     *            the identity of the object the new instance tracks.
     */
    public PackedObjectInfo(AnyObjectId id) {
        super(id);
    }

    /**
     * Get offset in pack when object has been already written
     *
     * @return offset in pack when object has been already written, or 0 if it
     *         has not been written yet
     */
    public long getOffset() {
        return offset;
    }

    /**
     * Set the offset in pack when object has been written to.
     *
     * @param offset
     *            offset where written object starts
     */
    public void setOffset(long offset) {
        this.offset = offset;
    }

    /**
     * Get the 32 bit CRC checksum for the packed data.
     *
     * @return the 32 bit CRC checksum for the packed data.
     */
    public int getCRC() {
        return crc;
    }

    /**
     * Record the 32 bit CRC checksum for the packed data.
     *
     * @param crc
     *            checksum of all packed data (including object type code,
     *            inflated length and delta base reference) as computed by
     *            {@link java.util.zip.CRC32}.
     */
    public void setCRC(int crc) {
        this.crc = crc;
    }

    /**
     * Get the object type.
     *
     * @return the object type. The default type is OBJ_BAD, which is considered
     *         as unknown or invalid type.
     * @since 4.9
     */
    public int getType() {
        return type;
    }

    /**
     * Record the object type if applicable.
     *
     * @param type
     *            the object type.
     * @since 4.9
     */
    public void setType(int type) {
        this.type = type;
    }
}