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1   /*
2    * Copyright (C) 2010, Google Inc.
3    * and other copyright owners as documented in the project's IP log.
4    *
5    * This program and the accompanying materials are made available
6    * under the terms of the Eclipse Distribution License v1.0 which
7    * accompanies this distribution, is reproduced below, and is
8    * available at http://www.eclipse.org/org/documents/edl-v10.php
9    *
10   * All rights reserved.
11   *
12   * Redistribution and use in source and binary forms, with or
13   * without modification, are permitted provided that the following
14   * conditions are met:
15   *
16   * - Redistributions of source code must retain the above copyright
17   *   notice, this list of conditions and the following disclaimer.
18   *
19   * - Redistributions in binary form must reproduce the above
20   *   copyright notice, this list of conditions and the following
21   *   disclaimer in the documentation and/or other materials provided
22   *   with the distribution.
23   *
24   * - Neither the name of the Eclipse Foundation, Inc. nor the
25   *   names of its contributors may be used to endorse or promote
26   *   products derived from this software without specific prior
27   *   written permission.
28   *
29   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30   * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42   */
43  
44  package org.eclipse.jgit.internal.storage.pack;
45  
46  import org.eclipse.jgit.lib.ObjectId;
47  
48  /**
49   * An object representation
50   * {@link org.eclipse.jgit.internal.storage.pack.PackWriter} can consider for
51   * packing.
52   */
53  public class StoredObjectRepresentation {
54  	/** Special unknown value for {@link #getWeight()}. */
55  	public static final int WEIGHT_UNKNOWN = Integer.MAX_VALUE;
56  
57  	/** Stored in pack format, as a delta to another object. */
58  	public static final int PACK_DELTA = 0;
59  
60  	/** Stored in pack format, without delta. */
61  	public static final int PACK_WHOLE = 1;
62  
63  	/** Only available after inflating to canonical format. */
64  	public static final int FORMAT_OTHER = 2;
65  
66  	/**
67  	 * Get relative size of this object's packed form.
68  	 *
69  	 * @return relative size of this object's packed form. The special value
70  	 *         {@link #WEIGHT_UNKNOWN} can be returned to indicate the
71  	 *         implementation doesn't know, or cannot supply the weight up
72  	 *         front.
73  	 */
74  	public int getWeight() {
75  		return WEIGHT_UNKNOWN;
76  	}
77  
78  	/**
79  	 * Get the storage format type
80  	 *
81  	 * @return the storage format type, which must be one of
82  	 *         {@link #PACK_DELTA}, {@link #PACK_WHOLE}, or
83  	 *         {@link #FORMAT_OTHER}.
84  	 */
85  	public int getFormat() {
86  		return FORMAT_OTHER;
87  	}
88  
89  	/**
90  	 * Get identity of the object this delta applies to in order to recover the
91  	 * original object content.
92  	 *
93  	 * @return identity of the object this delta applies to in order to recover
94  	 *         the original object content. This method should only be called if
95  	 *         {@link #getFormat()} returned {@link #PACK_DELTA}.
96  	 */
97  	public ObjectId getDeltaBase() {
98  		return null;
99  	}
100 
101 	/**
102 	 * Whether the current representation of the object has had delta
103 	 * compression attempted on it.
104 	 *
105 	 * @return whether the current representation of the object has had delta
106 	 *         compression attempted on it.
107 	 */
108 	public boolean wasDeltaAttempted() {
109 		int fmt = getFormat();
110 		return fmt == PACK_DELTA || fmt == PACK_WHOLE;
111 	}
112 }