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Commit | Line | Data |
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27225f2e | 1 | #include <ctype.h> |
c323ac7d LT |
2 | #include "cache.h" |
3 | #include "object.h" | |
4 | #include "delta.h" | |
a733cb60 | 5 | #include "pack.h" |
c38138cd | 6 | #include "csum-file.h" |
c323ac7d | 7 | |
d22b9290 | 8 | static const char pack_usage[] = "git-pack-objects [--window=N] [--depth=N] {--stdout | base-name} < object-list"; |
c323ac7d | 9 | |
c323ac7d LT |
10 | struct object_entry { |
11 | unsigned char sha1[20]; | |
12 | unsigned long size; | |
13 | unsigned long offset; | |
14 | unsigned int depth; | |
27225f2e | 15 | unsigned int hash; |
a733cb60 | 16 | enum object_type type; |
c323ac7d LT |
17 | unsigned long delta_size; |
18 | struct object_entry *delta; | |
19 | }; | |
20 | ||
21 | static struct object_entry **sorted_by_sha, **sorted_by_type; | |
22 | static struct object_entry *objects = NULL; | |
23 | static int nr_objects = 0, nr_alloc = 0; | |
c323ac7d | 24 | static const char *base_name; |
e1808845 | 25 | static unsigned char pack_file_sha1[20]; |
c323ac7d | 26 | |
c323ac7d LT |
27 | static void *delta_against(void *buf, unsigned long size, struct object_entry *entry) |
28 | { | |
29 | unsigned long othersize, delta_size; | |
30 | char type[10]; | |
31 | void *otherbuf = read_sha1_file(entry->delta->sha1, type, &othersize); | |
32 | void *delta_buf; | |
33 | ||
34 | if (!otherbuf) | |
35 | die("unable to read %s", sha1_to_hex(entry->delta->sha1)); | |
8ee378a0 JH |
36 | delta_buf = diff_delta(otherbuf, othersize, |
37 | buf, size, &delta_size, ~0UL); | |
75c42d8c | 38 | if (!delta_buf || delta_size != entry->delta_size) |
c323ac7d LT |
39 | die("delta size changed"); |
40 | free(buf); | |
41 | free(otherbuf); | |
42 | return delta_buf; | |
43 | } | |
44 | ||
a733cb60 LT |
45 | /* |
46 | * The per-object header is a pretty dense thing, which is | |
47 | * - first byte: low four bits are "size", then three bits of "type", | |
48 | * and the high bit is "size continues". | |
49 | * - each byte afterwards: low seven bits are size continuation, | |
50 | * with the high bit being "size continues" | |
51 | */ | |
52 | static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr) | |
53 | { | |
54 | int n = 1, i; | |
55 | unsigned char c; | |
56 | ||
57 | if (type < OBJ_COMMIT || type > OBJ_DELTA) | |
58 | die("bad type %d", type); | |
59 | ||
60 | /* | |
61 | * Shift the size up by 7 bits at a time, | |
62 | * until you get bits in the "high four". | |
63 | * That will be our beginning. We'll have | |
64 | * four size bits in 28..31, then groups | |
65 | * of seven in 21..27, 14..20, 7..13 and | |
66 | * finally 0..6. | |
67 | */ | |
68 | if (size) { | |
69 | n = 5; | |
70 | while (!(size & 0xfe000000)) { | |
71 | size <<= 7; | |
72 | n--; | |
73 | } | |
74 | } | |
75 | c = (type << 4) | (size >> 28); | |
76 | for (i = 1; i < n; i++) { | |
77 | *hdr++ = c | 0x80; | |
78 | c = (size >> 21) & 0x7f; | |
79 | size <<= 7; | |
80 | } | |
81 | *hdr = c; | |
82 | return n; | |
83 | } | |
84 | ||
c38138cd | 85 | static unsigned long write_object(struct sha1file *f, struct object_entry *entry) |
c323ac7d LT |
86 | { |
87 | unsigned long size; | |
88 | char type[10]; | |
89 | void *buf = read_sha1_file(entry->sha1, type, &size); | |
a733cb60 | 90 | unsigned char header[10]; |
c323ac7d | 91 | unsigned hdrlen, datalen; |
a733cb60 | 92 | enum object_type obj_type; |
c323ac7d LT |
93 | |
94 | if (!buf) | |
95 | die("unable to read %s", sha1_to_hex(entry->sha1)); | |
96 | if (size != entry->size) | |
97 | die("object %s size inconsistency (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size); | |
98 | ||
99 | /* | |
e1ddc976 JH |
100 | * The object header is a byte of 'type' followed by zero or |
101 | * more bytes of length. For deltas, the 20 bytes of delta sha1 | |
102 | * follows that. | |
c323ac7d | 103 | */ |
a733cb60 | 104 | obj_type = entry->type; |
c323ac7d | 105 | if (entry->delta) { |
c323ac7d LT |
106 | buf = delta_against(buf, size, entry); |
107 | size = entry->delta_size; | |
a733cb60 | 108 | obj_type = OBJ_DELTA; |
c323ac7d | 109 | } |
a733cb60 | 110 | hdrlen = encode_header(obj_type, size, header); |
c38138cd | 111 | sha1write(f, header, hdrlen); |
a733cb60 LT |
112 | if (entry->delta) { |
113 | sha1write(f, entry->delta, 20); | |
114 | hdrlen += 20; | |
115 | } | |
c38138cd | 116 | datalen = sha1write_compressed(f, buf, size); |
c323ac7d LT |
117 | free(buf); |
118 | return hdrlen + datalen; | |
119 | } | |
120 | ||
121 | static void write_pack_file(void) | |
122 | { | |
123 | int i; | |
d22b9290 | 124 | struct sha1file *f; |
a733cb60 | 125 | unsigned long offset; |
c323ac7d | 126 | unsigned long mb; |
a733cb60 | 127 | struct pack_header hdr; |
c323ac7d | 128 | |
d22b9290 LT |
129 | if (!base_name) |
130 | f = sha1fd(1, "<stdout>"); | |
131 | else | |
132 | f = sha1create("%s.%s", base_name, "pack"); | |
a733cb60 LT |
133 | hdr.hdr_signature = htonl(PACK_SIGNATURE); |
134 | hdr.hdr_version = htonl(1); | |
135 | hdr.hdr_entries = htonl(nr_objects); | |
136 | sha1write(f, &hdr, sizeof(hdr)); | |
137 | offset = sizeof(hdr); | |
c323ac7d LT |
138 | for (i = 0; i < nr_objects; i++) { |
139 | struct object_entry *entry = objects + i; | |
140 | entry->offset = offset; | |
141 | offset += write_object(f, entry); | |
142 | } | |
e1808845 | 143 | sha1close(f, pack_file_sha1, 1); |
c323ac7d LT |
144 | mb = offset >> 20; |
145 | offset &= 0xfffff; | |
146 | } | |
147 | ||
148 | static void write_index_file(void) | |
149 | { | |
150 | int i; | |
c38138cd | 151 | struct sha1file *f = sha1create("%s.%s", base_name, "idx"); |
c323ac7d LT |
152 | struct object_entry **list = sorted_by_sha; |
153 | struct object_entry **last = list + nr_objects; | |
154 | unsigned int array[256]; | |
155 | ||
156 | /* | |
157 | * Write the first-level table (the list is sorted, | |
158 | * but we use a 256-entry lookup to be able to avoid | |
e1808845 | 159 | * having to do eight extra binary search iterations). |
c323ac7d LT |
160 | */ |
161 | for (i = 0; i < 256; i++) { | |
162 | struct object_entry **next = list; | |
163 | while (next < last) { | |
164 | struct object_entry *entry = *next; | |
165 | if (entry->sha1[0] != i) | |
166 | break; | |
167 | next++; | |
168 | } | |
169 | array[i] = htonl(next - sorted_by_sha); | |
170 | list = next; | |
171 | } | |
c38138cd | 172 | sha1write(f, array, 256 * sizeof(int)); |
c323ac7d LT |
173 | |
174 | /* | |
175 | * Write the actual SHA1 entries.. | |
176 | */ | |
177 | list = sorted_by_sha; | |
49397104 | 178 | for (i = 0; i < nr_objects; i++) { |
c323ac7d LT |
179 | struct object_entry *entry = *list++; |
180 | unsigned int offset = htonl(entry->offset); | |
c38138cd LT |
181 | sha1write(f, &offset, 4); |
182 | sha1write(f, entry->sha1, 20); | |
c323ac7d | 183 | } |
e1808845 LT |
184 | sha1write(f, pack_file_sha1, 20); |
185 | sha1close(f, NULL, 1); | |
c323ac7d LT |
186 | } |
187 | ||
27225f2e | 188 | static void add_object_entry(unsigned char *sha1, unsigned int hash) |
c323ac7d LT |
189 | { |
190 | unsigned int idx = nr_objects; | |
191 | struct object_entry *entry; | |
192 | ||
193 | if (idx >= nr_alloc) { | |
194 | unsigned int needed = (idx + 1024) * 3 / 2; | |
195 | objects = xrealloc(objects, needed * sizeof(*entry)); | |
196 | nr_alloc = needed; | |
197 | } | |
198 | entry = objects + idx; | |
199 | memset(entry, 0, sizeof(*entry)); | |
200 | memcpy(entry->sha1, sha1, 20); | |
27225f2e | 201 | entry->hash = hash; |
c323ac7d LT |
202 | nr_objects = idx+1; |
203 | } | |
204 | ||
205 | static void check_object(struct object_entry *entry) | |
206 | { | |
36e4d74a JH |
207 | char type[20]; |
208 | ||
209 | if (!sha1_object_info(entry->sha1, type, &entry->size)) { | |
210 | if (!strcmp(type, "commit")) { | |
a733cb60 | 211 | entry->type = OBJ_COMMIT; |
36e4d74a | 212 | } else if (!strcmp(type, "tree")) { |
a733cb60 | 213 | entry->type = OBJ_TREE; |
36e4d74a | 214 | } else if (!strcmp(type, "blob")) { |
a733cb60 | 215 | entry->type = OBJ_BLOB; |
a69d0943 | 216 | } else if (!strcmp(type, "tag")) { |
a733cb60 | 217 | entry->type = OBJ_TAG; |
36e4d74a JH |
218 | } else |
219 | die("unable to pack object %s of type %s", | |
220 | sha1_to_hex(entry->sha1), type); | |
221 | } | |
222 | else | |
223 | die("unable to get type of object %s", | |
224 | sha1_to_hex(entry->sha1)); | |
c323ac7d LT |
225 | } |
226 | ||
227 | static void get_object_details(void) | |
228 | { | |
229 | int i; | |
230 | struct object_entry *entry = objects; | |
231 | ||
232 | for (i = 0; i < nr_objects; i++) | |
233 | check_object(entry++); | |
234 | } | |
235 | ||
236 | typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *); | |
237 | ||
238 | static entry_sort_t current_sort; | |
239 | ||
240 | static int sort_comparator(const void *_a, const void *_b) | |
241 | { | |
242 | struct object_entry *a = *(struct object_entry **)_a; | |
243 | struct object_entry *b = *(struct object_entry **)_b; | |
244 | return current_sort(a,b); | |
245 | } | |
246 | ||
247 | static struct object_entry **create_sorted_list(entry_sort_t sort) | |
248 | { | |
249 | struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *)); | |
250 | int i; | |
251 | ||
252 | for (i = 0; i < nr_objects; i++) | |
253 | list[i] = objects + i; | |
254 | current_sort = sort; | |
255 | qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator); | |
256 | return list; | |
257 | } | |
258 | ||
259 | static int sha1_sort(const struct object_entry *a, const struct object_entry *b) | |
260 | { | |
261 | return memcmp(a->sha1, b->sha1, 20); | |
262 | } | |
263 | ||
264 | static int type_size_sort(const struct object_entry *a, const struct object_entry *b) | |
265 | { | |
266 | if (a->type < b->type) | |
267 | return -1; | |
268 | if (a->type > b->type) | |
269 | return 1; | |
27225f2e LT |
270 | if (a->hash < b->hash) |
271 | return -1; | |
272 | if (a->hash > b->hash) | |
273 | return 1; | |
c323ac7d LT |
274 | if (a->size < b->size) |
275 | return -1; | |
276 | if (a->size > b->size) | |
277 | return 1; | |
278 | return a < b ? -1 : (a > b); | |
279 | } | |
280 | ||
281 | struct unpacked { | |
282 | struct object_entry *entry; | |
283 | void *data; | |
284 | }; | |
285 | ||
286 | /* | |
521a4f4c LT |
287 | * We search for deltas _backwards_ in a list sorted by type and |
288 | * by size, so that we see progressively smaller and smaller files. | |
289 | * That's because we prefer deltas to be from the bigger file | |
290 | * to the smaller - deletes are potentially cheaper, but perhaps | |
291 | * more importantly, the bigger file is likely the more recent | |
292 | * one. | |
c323ac7d | 293 | */ |
d116a45a | 294 | static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_depth) |
c323ac7d LT |
295 | { |
296 | struct object_entry *cur_entry = cur->entry; | |
297 | struct object_entry *old_entry = old->entry; | |
521a4f4c | 298 | unsigned long size, oldsize, delta_size, sizediff; |
75c42d8c | 299 | long max_size; |
c323ac7d LT |
300 | void *delta_buf; |
301 | ||
302 | /* Don't bother doing diffs between different types */ | |
303 | if (cur_entry->type != old_entry->type) | |
304 | return -1; | |
305 | ||
c323ac7d | 306 | size = cur_entry->size; |
75c42d8c LT |
307 | if (size < 50) |
308 | return -1; | |
c323ac7d | 309 | oldsize = old_entry->size; |
521a4f4c LT |
310 | sizediff = oldsize > size ? oldsize - size : size - oldsize; |
311 | if (sizediff > size / 8) | |
c323ac7d | 312 | return -1; |
d116a45a LT |
313 | if (old_entry->depth >= max_depth) |
314 | return 0; | |
c323ac7d LT |
315 | |
316 | /* | |
317 | * NOTE! | |
318 | * | |
319 | * We always delta from the bigger to the smaller, since that's | |
320 | * more space-efficient (deletes don't have to say _what_ they | |
321 | * delete). | |
322 | */ | |
75c42d8c LT |
323 | max_size = size / 2 - 20; |
324 | if (cur_entry->delta) | |
325 | max_size = cur_entry->delta_size-1; | |
27225f2e LT |
326 | if (sizediff >= max_size) |
327 | return -1; | |
8ee378a0 JH |
328 | delta_buf = diff_delta(old->data, oldsize, |
329 | cur->data, size, &delta_size, max_size); | |
c323ac7d | 330 | if (!delta_buf) |
75c42d8c LT |
331 | return 0; |
332 | cur_entry->delta = old_entry; | |
333 | cur_entry->delta_size = delta_size; | |
d116a45a | 334 | cur_entry->depth = old_entry->depth + 1; |
c323ac7d | 335 | free(delta_buf); |
eb41ab11 | 336 | return 0; |
c323ac7d LT |
337 | } |
338 | ||
d116a45a | 339 | static void find_deltas(struct object_entry **list, int window, int depth) |
c323ac7d | 340 | { |
521a4f4c | 341 | int i, idx; |
c323ac7d LT |
342 | unsigned int array_size = window * sizeof(struct unpacked); |
343 | struct unpacked *array = xmalloc(array_size); | |
344 | ||
345 | memset(array, 0, array_size); | |
521a4f4c LT |
346 | i = nr_objects; |
347 | idx = 0; | |
348 | while (--i >= 0) { | |
c323ac7d LT |
349 | struct object_entry *entry = list[i]; |
350 | struct unpacked *n = array + idx; | |
351 | unsigned long size; | |
352 | char type[10]; | |
353 | int j; | |
354 | ||
355 | free(n->data); | |
356 | n->entry = entry; | |
357 | n->data = read_sha1_file(entry->sha1, type, &size); | |
358 | if (size != entry->size) | |
359 | die("object %s inconsistent object length (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size); | |
78817c15 LT |
360 | j = window; |
361 | while (--j > 0) { | |
362 | unsigned int other_idx = idx + j; | |
c323ac7d | 363 | struct unpacked *m; |
78817c15 LT |
364 | if (other_idx >= window) |
365 | other_idx -= window; | |
c323ac7d LT |
366 | m = array + other_idx; |
367 | if (!m->entry) | |
368 | break; | |
d116a45a | 369 | if (try_delta(n, m, depth) < 0) |
c323ac7d LT |
370 | break; |
371 | } | |
521a4f4c LT |
372 | idx++; |
373 | if (idx >= window) | |
374 | idx = 0; | |
c323ac7d LT |
375 | } |
376 | } | |
377 | ||
378 | int main(int argc, char **argv) | |
379 | { | |
27225f2e | 380 | char line[PATH_MAX + 20]; |
d22b9290 | 381 | int window = 10, depth = 10, pack_to_stdout = 0; |
c323ac7d LT |
382 | int i; |
383 | ||
384 | for (i = 1; i < argc; i++) { | |
385 | const char *arg = argv[i]; | |
386 | ||
387 | if (*arg == '-') { | |
388 | if (!strncmp("--window=", arg, 9)) { | |
389 | char *end; | |
f846bbff | 390 | window = strtoul(arg+9, &end, 0); |
c323ac7d LT |
391 | if (!arg[9] || *end) |
392 | usage(pack_usage); | |
393 | continue; | |
394 | } | |
d116a45a LT |
395 | if (!strncmp("--depth=", arg, 8)) { |
396 | char *end; | |
397 | depth = strtoul(arg+8, &end, 0); | |
398 | if (!arg[8] || *end) | |
399 | usage(pack_usage); | |
400 | continue; | |
401 | } | |
d22b9290 LT |
402 | if (!strcmp("--stdout", arg)) { |
403 | pack_to_stdout = 1; | |
404 | continue; | |
405 | } | |
c323ac7d LT |
406 | usage(pack_usage); |
407 | } | |
408 | if (base_name) | |
409 | usage(pack_usage); | |
410 | base_name = arg; | |
411 | } | |
412 | ||
d22b9290 | 413 | if (pack_to_stdout != !base_name) |
c323ac7d LT |
414 | usage(pack_usage); |
415 | ||
416 | while (fgets(line, sizeof(line), stdin) != NULL) { | |
27225f2e LT |
417 | unsigned int hash; |
418 | char *p; | |
c323ac7d | 419 | unsigned char sha1[20]; |
27225f2e | 420 | |
c323ac7d LT |
421 | if (get_sha1_hex(line, sha1)) |
422 | die("expected sha1, got garbage"); | |
27225f2e LT |
423 | hash = 0; |
424 | p = line+40; | |
425 | while (*p) { | |
426 | unsigned char c = *p++; | |
427 | if (isspace(c)) | |
428 | continue; | |
429 | hash = hash * 11 + c; | |
430 | } | |
431 | add_object_entry(sha1, hash); | |
c323ac7d LT |
432 | } |
433 | get_object_details(); | |
434 | ||
d22b9290 | 435 | fprintf(stderr, "Packing %d objects\n", nr_objects); |
c323ac7d LT |
436 | |
437 | sorted_by_sha = create_sorted_list(sha1_sort); | |
438 | sorted_by_type = create_sorted_list(type_size_sort); | |
d116a45a LT |
439 | if (window && depth) |
440 | find_deltas(sorted_by_type, window+1, depth); | |
c323ac7d LT |
441 | |
442 | write_pack_file(); | |
d22b9290 LT |
443 | if (!pack_to_stdout) |
444 | write_index_file(); | |
c323ac7d LT |
445 | return 0; |
446 | } |