org.spearce.jgit/src/org/spearce/jgit/transport/PackedObjectInfo.java

   1 /*
   2  * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
   3  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
   4  *
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or
   8  * without modification, are permitted provided that the following
   9  * conditions are met:
  10  *
  11  * - Redistributions of source code must retain the above copyright
  12  *   notice, this list of conditions and the following disclaimer.
  13  *
  14  * - Redistributions in binary form must reproduce the above
  15  *   copyright notice, this list of conditions and the following
  16  *   disclaimer in the documentation and/or other materials provided
  17  *   with the distribution.
  18  *
  19  * - Neither the name of the Git Development Community nor the
  20  *   names of its contributors may be used to endorse or promote
  21  *   products derived from this software without specific prior
  22  *   written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  25  * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  26  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  29  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  32  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  33  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  34  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  36  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 package org.spearce.jgit.transport;
  40
  41 import org.spearce.jgit.lib.AnyObjectId;
  42 import org.spearce.jgit.lib.ObjectId;
  43
  44 /**
  45  * Description of an object stored in a pack file, including offset.
  46  * <p>
  47  * When objects are stored in packs Git needs the ObjectId and the offset
  48  * (starting position of the object data) to perform random-access reads of
  49  * objects from the pack. This extension of ObjectId includes the offset.
  50  */
  51 public class PackedObjectInfo extends ObjectId {
  52         private long offset;
  53
  54         private int crc;
  55
  56         PackedObjectInfo(final long headerOffset, final int packedCRC,
  57                         final AnyObjectId id) {
  58                 super(id);
  59                 offset = headerOffset;
  60                 crc = packedCRC;
  61         }
  62
  63         /**
  64          * Create a new structure to remember information about an object.
  65          *
  66          * @param id
  67          *            the identity of the object the new instance tracks.
  68          */
  69         public PackedObjectInfo(final AnyObjectId id) {
  70                 super(id);
  71         }
  72
  73         /**
  74          * @return offset in pack when object has been already written, or 0 if it
  75          *         has not been written yet
  76          */
  77         public long getOffset() {
  78                 return offset;
  79         }
  80
  81         /**
  82          * Set the offset in pack when object has been written to.
  83          *
  84          * @param offset
  85          *            offset where written object starts
  86          */
  87         public void setOffset(final long offset) {
  88                 this.offset = offset;
  89         }
  90
  91         /**
  92          * @return the 32 bit CRC checksum for the packed data.
  93          */
  94         public int getCRC() {
  95                 return crc;
  96         }
  97
  98         /**
  99          * Record the 32 bit CRC checksum for the packed data.
 100          *
 101          * @param crc
 102          *            checksum of all packed data (including object type code,
 103          *            inflated length and delta base reference) as computed by
 104          *            {@link java.util.zip.CRC32}.
 105          */
 106         public void setCRC(final int crc) {
 107                 this.crc = crc;
 108         }
 109 }