1 /*
2 * Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
3 * Copyright (C) 2006-2008, Shawn O. Pearce <spearce@spearce.org>
4 * and other copyright owners as documented in the project's IP log.
5 *
6 * This program and the accompanying materials are made available
7 * under the terms of the Eclipse Distribution License v1.0 which
8 * accompanies this distribution, is reproduced below, and is
9 * available at http://www.eclipse.org/org/documents/edl-v10.php
10 *
11 * All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or
14 * without modification, are permitted provided that the following
15 * conditions are met:
16 *
17 * - Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * - Redistributions in binary form must reproduce the above
21 * copyright notice, this list of conditions and the following
22 * disclaimer in the documentation and/or other materials provided
23 * with the distribution.
24 *
25 * - Neither the name of the Eclipse Foundation, Inc. nor the
26 * names of its contributors may be used to endorse or promote
27 * products derived from this software without specific prior
28 * written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
31 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
32 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
34 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
35 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
36 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
38 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
39 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
41 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
42 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43 */
44
45 package org.eclipse.jgit.lib;
46
47 import java.io.IOException;
48 import java.io.ObjectInputStream;
49 import java.io.ObjectOutputStream;
50 import java.io.Serializable;
51
52 import org.eclipse.jgit.errors.InvalidObjectIdException;
53 import org.eclipse.jgit.util.NB;
54 import org.eclipse.jgit.util.RawParseUtils;
55
56 /**
57 * A SHA-1 abstraction.
58 */
59 public class ObjectId extends AnyObjectId implements Serializable {
60 private static final long serialVersionUID = 1L;
61
62 private static final ObjectId ZEROID;
63
64 private static final String ZEROID_STR;
65
66 static {
67 ZEROID = new ObjectId(0, 0, 0, 0, 0);
68 ZEROID_STR = ZEROID.name();
69 }
70
71 /**
72 * Get the special all-null ObjectId.
73 *
74 * @return the all-null ObjectId, often used to stand-in for no object.
75 */
76 public static final ObjectId zeroId() {
77 return ZEROID;
78 }
79
80 /**
81 * Test a string of characters to verify it is a hex format.
82 * <p>
83 * If true the string can be parsed with {@link #fromString(String)}.
84 *
85 * @param id
86 * the string to test.
87 * @return true if the string can converted into an ObjectId.
88 */
89 public static final boolean isId(final String id) {
90 if (id.length() != Constants.OBJECT_ID_STRING_LENGTH)
91 return false;
92 try {
93 for (int i = 0; i < Constants.OBJECT_ID_STRING_LENGTH; i++) {
94 RawParseUtils.parseHexInt4((byte) id.charAt(i));
95 }
96 return true;
97 } catch (ArrayIndexOutOfBoundsException e) {
98 return false;
99 }
100 }
101
102 /**
103 * Convert an ObjectId into a hex string representation.
104 *
105 * @param i
106 * the id to convert. May be null.
107 * @return the hex string conversion of this id's content.
108 */
109 public static final String toString(final ObjectId i) {
110 return i != null ? i.name() : ZEROID_STR;
111 }
112
113 /**
114 * Compare two object identifier byte sequences for equality.
115 *
116 * @param firstBuffer
117 * the first buffer to compare against. Must have at least 20
118 * bytes from position fi through the end of the buffer.
119 * @param fi
120 * first offset within firstBuffer to begin testing.
121 * @param secondBuffer
122 * the second buffer to compare against. Must have at least 20
123 * bytes from position si through the end of the buffer.
124 * @param si
125 * first offset within secondBuffer to begin testing.
126 * @return true if the two identifiers are the same.
127 */
128 public static boolean equals(final byte[] firstBuffer, final int fi,
129 final byte[] secondBuffer, final int si) {
130 return firstBuffer[fi] == secondBuffer[si]
131 && firstBuffer[fi + 1] == secondBuffer[si + 1]
132 && firstBuffer[fi + 2] == secondBuffer[si + 2]
133 && firstBuffer[fi + 3] == secondBuffer[si + 3]
134 && firstBuffer[fi + 4] == secondBuffer[si + 4]
135 && firstBuffer[fi + 5] == secondBuffer[si + 5]
136 && firstBuffer[fi + 6] == secondBuffer[si + 6]
137 && firstBuffer[fi + 7] == secondBuffer[si + 7]
138 && firstBuffer[fi + 8] == secondBuffer[si + 8]
139 && firstBuffer[fi + 9] == secondBuffer[si + 9]
140 && firstBuffer[fi + 10] == secondBuffer[si + 10]
141 && firstBuffer[fi + 11] == secondBuffer[si + 11]
142 && firstBuffer[fi + 12] == secondBuffer[si + 12]
143 && firstBuffer[fi + 13] == secondBuffer[si + 13]
144 && firstBuffer[fi + 14] == secondBuffer[si + 14]
145 && firstBuffer[fi + 15] == secondBuffer[si + 15]
146 && firstBuffer[fi + 16] == secondBuffer[si + 16]
147 && firstBuffer[fi + 17] == secondBuffer[si + 17]
148 && firstBuffer[fi + 18] == secondBuffer[si + 18]
149 && firstBuffer[fi + 19] == secondBuffer[si + 19];
150 }
151
152 /**
153 * Convert an ObjectId from raw binary representation.
154 *
155 * @param bs
156 * the raw byte buffer to read from. At least 20 bytes must be
157 * available within this byte array.
158 * @return the converted object id.
159 */
160 public static final ObjectId fromRaw(final byte[] bs) {
161 return fromRaw(bs, 0);
162 }
163
164 /**
165 * Convert an ObjectId from raw binary representation.
166 *
167 * @param bs
168 * the raw byte buffer to read from. At least 20 bytes after p
169 * must be available within this byte array.
170 * @param p
171 * position to read the first byte of data from.
172 * @return the converted object id.
173 */
174 public static final ObjectId fromRaw(final byte[] bs, final int p) {
175 final int a = NB.decodeInt32(bs, p);
176 final int b = NB.decodeInt32(bs, p + 4);
177 final int c = NB.decodeInt32(bs, p + 8);
178 final int d = NB.decodeInt32(bs, p + 12);
179 final int e = NB.decodeInt32(bs, p + 16);
180 return new ObjectId(a, b, c, d, e);
181 }
182
183 /**
184 * Convert an ObjectId from raw binary representation.
185 *
186 * @param is
187 * the raw integers buffer to read from. At least 5 integers must
188 * be available within this int array.
189 * @return the converted object id.
190 */
191 public static final ObjectId fromRaw(final int[] is) {
192 return fromRaw(is, 0);
193 }
194
195 /**
196 * Convert an ObjectId from raw binary representation.
197 *
198 * @param is
199 * the raw integers buffer to read from. At least 5 integers
200 * after p must be available within this int array.
201 * @param p
202 * position to read the first integer of data from.
203 * @return the converted object id.
204 */
205 public static final ObjectId fromRaw(final int[] is, final int p) {
206 return new ObjectId(is[p], is[p + 1], is[p + 2], is[p + 3], is[p + 4]);
207 }
208
209 /**
210 * Convert an ObjectId from hex characters (US-ASCII).
211 *
212 * @param buf
213 * the US-ASCII buffer to read from. At least 40 bytes after
214 * offset must be available within this byte array.
215 * @param offset
216 * position to read the first character from.
217 * @return the converted object id.
218 */
219 public static final ObjectId fromString(final byte[] buf, final int offset) {
220 return fromHexString(buf, offset);
221 }
222
223 /**
224 * Convert an ObjectId from hex characters.
225 *
226 * @param str
227 * the string to read from. Must be 40 characters long.
228 * @return the converted object id.
229 */
230 public static ObjectId fromString(final String str) {
231 if (str.length() != Constants.OBJECT_ID_STRING_LENGTH) {
232 throw new InvalidObjectIdException(str);
233 }
234 return fromHexString(Constants.encodeASCII(str), 0);
235 }
236
237 private static final ObjectId fromHexString(final byte[] bs, int p) {
238 try {
239 final int a = RawParseUtils.parseHexInt32(bs, p);
240 final int b = RawParseUtils.parseHexInt32(bs, p + 8);
241 final int c = RawParseUtils.parseHexInt32(bs, p + 16);
242 final int d = RawParseUtils.parseHexInt32(bs, p + 24);
243 final int e = RawParseUtils.parseHexInt32(bs, p + 32);
244 return new ObjectId(a, b, c, d, e);
245 } catch (ArrayIndexOutOfBoundsException e1) {
246 throw new InvalidObjectIdException(bs, p,
247 Constants.OBJECT_ID_STRING_LENGTH);
248 }
249 }
250
251 /**
252 * Construct an ObjectId from 160 bits provided in 5 words.
253 *
254 * @param new_1
255 * @param new_2
256 * @param new_3
257 * @param new_4
258 * @param new_5
259 * @since 4.7
260 */
261 public ObjectId(int new_1, int new_2, int new_3, int new_4, int new_5) {
262 w1 = new_1;
263 w2 = new_2;
264 w3 = new_3;
265 w4 = new_4;
266 w5 = new_5;
267 }
268
269 /**
270 * Initialize this instance by copying another existing ObjectId.
271 * <p>
272 * This constructor is mostly useful for subclasses who want to extend an
273 * ObjectId with more properties, but initialize from an existing ObjectId
274 * instance acquired by other means.
275 *
276 * @param src
277 * another already parsed ObjectId to copy the value out of.
278 */
279 protected ObjectId(final AnyObjectId src) {
280 w1 = src.w1;
281 w2 = src.w2;
282 w3 = src.w3;
283 w4 = src.w4;
284 w5 = src.w5;
285 }
286
287 @Override
288 public ObjectId toObjectId() {
289 return this;
290 }
291
292 private void writeObject(ObjectOutputStream os) throws IOException {
293 os.writeInt(w1);
294 os.writeInt(w2);
295 os.writeInt(w3);
296 os.writeInt(w4);
297 os.writeInt(w5);
298 }
299
300 private void readObject(ObjectInputStream ois) throws IOException {
301 w1 = ois.readInt();
302 w2 = ois.readInt();
303 w3 = ois.readInt();
304 w4 = ois.readInt();
305 w5 = ois.readInt();
306 }
307 }