Mercurial > hg4j

comparison src/org/tmatesoft/hg/core/Nodeid.java @ 598:d29d9dc6c128

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Utilize the fact nodeids are very different and are read anyway to speed up reverse lookup
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Fri, 03 May 2013 15:19:18 +0200
parents d9c07e1432c4
children
comparison
equal deleted inserted replaced
597:c895b5556937 598:d29d9dc6c128
31 * @author Artem Tikhomirov 31 * @author Artem Tikhomirov
32 * @author TMate Software Ltd. 32 * @author TMate Software Ltd.
33 * 33 *
34 */ 34 */
35 public final class Nodeid implements Comparable<Nodeid> { 35 public final class Nodeid implements Comparable<Nodeid> {
36 36
37 /**
38 * Length of the nodeid in bytes
39 */
40 public static final int SIZE = 20;
41
42 /**
43 * Length of nodeid string representation, in bytes
44 */
45 public static final int SIZE_ASCII = 40;
46
37 /** 47 /**
38 * <b>nullid</b>, empty root revision. 48 * <b>nullid</b>, empty root revision.
39 */ 49 */
40 public static final Nodeid NULL = new Nodeid(new byte[20], false); 50 public static final Nodeid NULL = new Nodeid(new byte[SIZE], false);
41 51
42 private final byte[] binaryData; 52 private final byte[] binaryData;
43 53
44 /** 54 /**
45 * @param binaryRepresentation - array of exactly 20 bytes 55 * @param binaryRepresentation - array of exactly 20 bytes
47 * @throws HgBadNodeidFormatException custom {@link IllegalArgumentException} subclass if supplied binary representation doesn't correspond to 20 bytes of sha1 digest 57 * @throws HgBadNodeidFormatException custom {@link IllegalArgumentException} subclass if supplied binary representation doesn't correspond to 20 bytes of sha1 digest
48 */ 58 */
49 public Nodeid(byte[] binaryRepresentation, boolean shallClone) { 59 public Nodeid(byte[] binaryRepresentation, boolean shallClone) {
50 // 5 int fields => 32 bytes 60 // 5 int fields => 32 bytes
51 // byte[20] => 48 bytes (16 bytes is Nodeid with one field, 32 bytes for byte[20] 61 // byte[20] => 48 bytes (16 bytes is Nodeid with one field, 32 bytes for byte[20]
52 if (binaryRepresentation == null || binaryRepresentation.length != 20) { 62 if (binaryRepresentation == null || binaryRepresentation.length != SIZE) {
53 throw new HgBadNodeidFormatException(String.format("Bad value: %s", String.valueOf(binaryRepresentation))); 63 throw new HgBadNodeidFormatException(String.format("Bad value: %s", String.valueOf(binaryRepresentation)));
54 } 64 }
55 /* 65 /*
56 * byte[].clone() is not reflected when ran with -agentlib:hprof=heap=sites 66 * byte[].clone() is not reflected when ran with -agentlib:hprof=heap=sites
57 * thus not to get puzzled why there are N Nodeids and much less byte[] instances, 67 * thus not to get puzzled why there are N Nodeids and much less byte[] instances,
67 binaryData = shallClone ? binaryRepresentation.clone() : binaryRepresentation; 77 binaryData = shallClone ? binaryRepresentation.clone() : binaryRepresentation;
68 } 78 }
69 79
70 @Override 80 @Override
71 public int hashCode() { 81 public int hashCode() {
82 return hashCode(binaryData);
83 }
84
85 /**
86 * Handy alternative to calculate hashcode without need to get {@link Nodeid} instance
87 * @param binaryNodeid array of exactly 20 bytes
88 * @return same value as <code>new Nodeid(binaryNodeid, false).hashCode()</code>
89 */
90 public static int hashCode(byte[] binaryNodeid) {
91 assert binaryNodeid.length == SIZE;
72 // digest (part thereof) seems to be nice candidate for the hashCode 92 // digest (part thereof) seems to be nice candidate for the hashCode
73 byte[] b = binaryData; 93 byte[] b = binaryNodeid;
74 return b[0] << 24 | (b[1] & 0xFF) << 16 | (b[2] & 0xFF) << 8 | (b[3] & 0xFF); 94 return b[0] << 24 | (b[1] & 0xFF) << 16 | (b[2] & 0xFF) << 8 | (b[3] & 0xFF);
75 } 95 }
76 96
77 @Override 97 @Override
78 public boolean equals(Object o) { 98 public boolean equals(Object o) {
91 111
92 public int compareTo(Nodeid o) { 112 public int compareTo(Nodeid o) {
93 if (this == o) { 113 if (this == o) {
94 return 0; 114 return 0;
95 } 115 }
96 for (int i = 0; i < 20; i++) { 116 for (int i = 0; i < SIZE; i++) {
97 if (binaryData[i] != o.binaryData[i]) { 117 if (binaryData[i] != o.binaryData[i]) {
98 // if we need truly ascending sort, need to respect byte sign 118 // if we need truly ascending sort, need to respect byte sign
99 // return (binaryData[i] & 0xFF) < (o.binaryData[i] & 0xFF) ? -1 : 1; 119 // return (binaryData[i] & 0xFF) < (o.binaryData[i] & 0xFF) ? -1 : 1;
100 // however, for our purposes partial sort is pretty enough 120 // however, for our purposes partial sort is pretty enough
101 return binaryData[i] < o.binaryData[i] ? -1 : 1; 121 return binaryData[i] < o.binaryData[i] ? -1 : 1;
119 139
120 public boolean isNull() { 140 public boolean isNull() {
121 if (this == NULL) { 141 if (this == NULL) {
122 return true; 142 return true;
123 } 143 }
124 for (int i = 0; i < 20; i++) { 144 for (int i = 0; i < SIZE; i++) {
125 if (this.binaryData[i] != 0) { 145 if (this.binaryData[i] != 0) {
126 return false; 146 return false;
127 } 147 }
128 } 148 }
129 return true; 149 return true;
141 * @param binaryRepresentation - byte array of a length at least offset + 20 161 * @param binaryRepresentation - byte array of a length at least offset + 20
142 * @param offset - index in the array to start from 162 * @param offset - index in the array to start from
143 * @throws HgBadNodeidFormatException custom {@link IllegalArgumentException} subclass when arguments don't select 20 bytes 163 * @throws HgBadNodeidFormatException custom {@link IllegalArgumentException} subclass when arguments don't select 20 bytes
144 */ 164 */
145 public static Nodeid fromBinary(byte[] binaryRepresentation, int offset) { 165 public static Nodeid fromBinary(byte[] binaryRepresentation, int offset) {
146 if (binaryRepresentation == null || binaryRepresentation.length - offset < 20) { 166 if (binaryRepresentation == null || binaryRepresentation.length - offset < SIZE) {
147 throw new HgBadNodeidFormatException(String.format("Bad value: %s", String.valueOf(binaryRepresentation))); 167 throw new HgBadNodeidFormatException(String.format("Bad value: %s", String.valueOf(binaryRepresentation)));
148 } 168 }
149 int i = 0; 169 int i = 0;
150 while (i < 20 && binaryRepresentation[offset+i] == 0) i++; 170 while (i < SIZE && binaryRepresentation[offset+i] == 0) i++;
151 if (i == 20) { 171 if (i == SIZE) {
152 return NULL; 172 return NULL;
153 } 173 }
154 if (offset == 0 && binaryRepresentation.length == 20) { 174 if (offset == 0 && binaryRepresentation.length == SIZE) {
155 return new Nodeid(binaryRepresentation, true); 175 return new Nodeid(binaryRepresentation, true);
156 } 176 }
157 byte[] b = new byte[20]; // create new instance if no other reasonable guesses possible 177 byte[] b = new byte[SIZE]; // create new instance if no other reasonable guesses possible
158 System.arraycopy(binaryRepresentation, offset, b, 0, 20); 178 System.arraycopy(binaryRepresentation, offset, b, 0, SIZE);
159 return new Nodeid(b, false); 179 return new Nodeid(b, false);
160 } 180 }
161 181
162 /** 182 /**
163 * Parse encoded representation. 183 * Parse encoded representation.
165 * @param asciiRepresentation - encoded form of the Nodeid. 185 * @param asciiRepresentation - encoded form of the Nodeid.
166 * @return object representation 186 * @return object representation
167 * @throws HgBadNodeidFormatException custom {@link IllegalArgumentException} subclass when argument doesn't match encoded form of 20-bytes sha1 digest. 187 * @throws HgBadNodeidFormatException custom {@link IllegalArgumentException} subclass when argument doesn't match encoded form of 20-bytes sha1 digest.
168 */ 188 */
169 public static Nodeid fromAscii(String asciiRepresentation) throws HgBadNodeidFormatException { 189 public static Nodeid fromAscii(String asciiRepresentation) throws HgBadNodeidFormatException {
170 if (asciiRepresentation.length() != 40) { 190 if (asciiRepresentation.length() != SIZE_ASCII) {
171 throw new HgBadNodeidFormatException(String.format("Bad value: %s", asciiRepresentation)); 191 throw new HgBadNodeidFormatException(String.format("Bad value: %s", asciiRepresentation));
172 } 192 }
173 // XXX is better impl for String possible? 193 // XXX is better impl for String possible?
174 return fromAscii(asciiRepresentation.toCharArray(), 0, 40); 194 return fromAscii(asciiRepresentation.toCharArray(), 0, SIZE_ASCII);
175 } 195 }
176 196
177 /** 197 /**
178 * Parse encoded representation. Similar to {@link #fromAscii(String)}. 198 * Parse encoded representation. Similar to {@link #fromAscii(String)}.
179 * @throws HgBadNodeidFormatException custom {@link IllegalArgumentException} subclass when bytes are not hex digits or number of bytes != 40 (160 bits) 199 * @throws HgBadNodeidFormatException custom {@link IllegalArgumentException} subclass when bytes are not hex digits or number of bytes != 40 (160 bits)
180 */ 200 */
181 public static Nodeid fromAscii(byte[] asciiRepresentation, int offset, int length) throws HgBadNodeidFormatException { 201 public static Nodeid fromAscii(byte[] asciiRepresentation, int offset, int length) throws HgBadNodeidFormatException {
182 if (length != 40) { 202 if (length != SIZE_ASCII) {
183 throw new HgBadNodeidFormatException(String.format("Expected 40 hex characters for nodeid, not %d", length)); 203 throw new HgBadNodeidFormatException(String.format("Expected %d hex characters for nodeid, not %d", SIZE_ASCII, length));
184 } 204 }
185 try { 205 try {
186 byte[] data = new byte[20]; 206 byte[] data = new byte[SIZE];
187 boolean zeroBytes = DigestHelper.ascii2bin(asciiRepresentation, offset, length, data); 207 boolean zeroBytes = DigestHelper.ascii2bin(asciiRepresentation, offset, length, data);
188 if (zeroBytes) { 208 if (zeroBytes) {
189 return NULL; 209 return NULL;
190 } 210 }
191 return new Nodeid(data, false); 211 return new Nodeid(data, false);