midx: use existing midx when writing new one
[git/git.git] / midx.c
1 #include "cache.h"
2 #include "config.h"
3 #include "csum-file.h"
4 #include "dir.h"
5 #include "lockfile.h"
6 #include "packfile.h"
7 #include "object-store.h"
8 #include "sha1-lookup.h"
9 #include "midx.h"
10
11 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
12 #define MIDX_VERSION 1
13 #define MIDX_BYTE_FILE_VERSION 4
14 #define MIDX_BYTE_HASH_VERSION 5
15 #define MIDX_BYTE_NUM_CHUNKS 6
16 #define MIDX_BYTE_NUM_PACKS 8
17 #define MIDX_HASH_VERSION 1
18 #define MIDX_HEADER_SIZE 12
19 #define MIDX_HASH_LEN 20
20 #define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN)
21
22 #define MIDX_MAX_CHUNKS 5
23 #define MIDX_CHUNK_ALIGNMENT 4
24 #define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
25 #define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
26 #define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
27 #define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
28 #define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
29 #define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
30 #define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
31 #define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
32 #define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
33 #define MIDX_LARGE_OFFSET_NEEDED 0x80000000
34
35 static char *get_midx_filename(const char *object_dir)
36 {
37 return xstrfmt("%s/pack/multi-pack-index", object_dir);
38 }
39
40 struct multi_pack_index *load_multi_pack_index(const char *object_dir)
41 {
42 struct multi_pack_index *m = NULL;
43 int fd;
44 struct stat st;
45 size_t midx_size;
46 void *midx_map = NULL;
47 uint32_t hash_version;
48 char *midx_name = get_midx_filename(object_dir);
49 uint32_t i;
50 const char *cur_pack_name;
51
52 fd = git_open(midx_name);
53
54 if (fd < 0)
55 goto cleanup_fail;
56 if (fstat(fd, &st)) {
57 error_errno(_("failed to read %s"), midx_name);
58 goto cleanup_fail;
59 }
60
61 midx_size = xsize_t(st.st_size);
62
63 if (midx_size < MIDX_MIN_SIZE) {
64 error(_("multi-pack-index file %s is too small"), midx_name);
65 goto cleanup_fail;
66 }
67
68 FREE_AND_NULL(midx_name);
69
70 midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
71
72 FLEX_ALLOC_MEM(m, object_dir, object_dir, strlen(object_dir));
73 m->fd = fd;
74 m->data = midx_map;
75 m->data_len = midx_size;
76
77 m->signature = get_be32(m->data);
78 if (m->signature != MIDX_SIGNATURE) {
79 error(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
80 m->signature, MIDX_SIGNATURE);
81 goto cleanup_fail;
82 }
83
84 m->version = m->data[MIDX_BYTE_FILE_VERSION];
85 if (m->version != MIDX_VERSION) {
86 error(_("multi-pack-index version %d not recognized"),
87 m->version);
88 goto cleanup_fail;
89 }
90
91 hash_version = m->data[MIDX_BYTE_HASH_VERSION];
92 if (hash_version != MIDX_HASH_VERSION) {
93 error(_("hash version %u does not match"), hash_version);
94 goto cleanup_fail;
95 }
96 m->hash_len = MIDX_HASH_LEN;
97
98 m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
99
100 m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
101
102 for (i = 0; i < m->num_chunks; i++) {
103 uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
104 MIDX_CHUNKLOOKUP_WIDTH * i);
105 uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
106 MIDX_CHUNKLOOKUP_WIDTH * i);
107
108 switch (chunk_id) {
109 case MIDX_CHUNKID_PACKNAMES:
110 m->chunk_pack_names = m->data + chunk_offset;
111 break;
112
113 case MIDX_CHUNKID_OIDFANOUT:
114 m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset);
115 break;
116
117 case MIDX_CHUNKID_OIDLOOKUP:
118 m->chunk_oid_lookup = m->data + chunk_offset;
119 break;
120
121 case MIDX_CHUNKID_OBJECTOFFSETS:
122 m->chunk_object_offsets = m->data + chunk_offset;
123 break;
124
125 case MIDX_CHUNKID_LARGEOFFSETS:
126 m->chunk_large_offsets = m->data + chunk_offset;
127 break;
128
129 case 0:
130 die(_("terminating multi-pack-index chunk id appears earlier than expected"));
131 break;
132
133 default:
134 /*
135 * Do nothing on unrecognized chunks, allowing future
136 * extensions to add optional chunks.
137 */
138 break;
139 }
140 }
141
142 if (!m->chunk_pack_names)
143 die(_("multi-pack-index missing required pack-name chunk"));
144 if (!m->chunk_oid_fanout)
145 die(_("multi-pack-index missing required OID fanout chunk"));
146 if (!m->chunk_oid_lookup)
147 die(_("multi-pack-index missing required OID lookup chunk"));
148 if (!m->chunk_object_offsets)
149 die(_("multi-pack-index missing required object offsets chunk"));
150
151 m->num_objects = ntohl(m->chunk_oid_fanout[255]);
152
153 m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
154 m->packs = xcalloc(m->num_packs, sizeof(*m->packs));
155
156 cur_pack_name = (const char *)m->chunk_pack_names;
157 for (i = 0; i < m->num_packs; i++) {
158 m->pack_names[i] = cur_pack_name;
159
160 cur_pack_name += strlen(cur_pack_name) + 1;
161
162 if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0) {
163 error(_("multi-pack-index pack names out of order: '%s' before '%s'"),
164 m->pack_names[i - 1],
165 m->pack_names[i]);
166 goto cleanup_fail;
167 }
168 }
169
170 return m;
171
172 cleanup_fail:
173 free(m);
174 free(midx_name);
175 if (midx_map)
176 munmap(midx_map, midx_size);
177 if (0 <= fd)
178 close(fd);
179 return NULL;
180 }
181
182 static void close_midx(struct multi_pack_index *m)
183 {
184 uint32_t i;
185 munmap((unsigned char *)m->data, m->data_len);
186 close(m->fd);
187 m->fd = -1;
188
189 for (i = 0; i < m->num_packs; i++) {
190 if (m->packs[i]) {
191 close_pack(m->packs[i]);
192 free(m->packs);
193 }
194 }
195 FREE_AND_NULL(m->packs);
196 FREE_AND_NULL(m->pack_names);
197 }
198
199 static int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
200 {
201 struct strbuf pack_name = STRBUF_INIT;
202
203 if (pack_int_id >= m->num_packs)
204 BUG("bad pack-int-id");
205
206 if (m->packs[pack_int_id])
207 return 0;
208
209 strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
210 m->pack_names[pack_int_id]);
211
212 m->packs[pack_int_id] = add_packed_git(pack_name.buf, pack_name.len, 1);
213 strbuf_release(&pack_name);
214 return !m->packs[pack_int_id];
215 }
216
217 int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
218 {
219 return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
220 MIDX_HASH_LEN, result);
221 }
222
223 struct object_id *nth_midxed_object_oid(struct object_id *oid,
224 struct multi_pack_index *m,
225 uint32_t n)
226 {
227 if (n >= m->num_objects)
228 return NULL;
229
230 hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
231 return oid;
232 }
233
234 static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
235 {
236 const unsigned char *offset_data;
237 uint32_t offset32;
238
239 offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH;
240 offset32 = get_be32(offset_data + sizeof(uint32_t));
241
242 if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
243 if (sizeof(offset32) < sizeof(uint64_t))
244 die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
245
246 offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
247 return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
248 }
249
250 return offset32;
251 }
252
253 static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
254 {
255 return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH);
256 }
257
258 static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *e, uint32_t pos)
259 {
260 uint32_t pack_int_id;
261 struct packed_git *p;
262
263 if (pos >= m->num_objects)
264 return 0;
265
266 pack_int_id = nth_midxed_pack_int_id(m, pos);
267
268 if (prepare_midx_pack(m, pack_int_id))
269 die(_("error preparing packfile from multi-pack-index"));
270 p = m->packs[pack_int_id];
271
272 /*
273 * We are about to tell the caller where they can locate the
274 * requested object. We better make sure the packfile is
275 * still here and can be accessed before supplying that
276 * answer, as it may have been deleted since the MIDX was
277 * loaded!
278 */
279 if (!is_pack_valid(p))
280 return 0;
281
282 e->offset = nth_midxed_offset(m, pos);
283 e->p = p;
284
285 return 1;
286 }
287
288 int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m)
289 {
290 uint32_t pos;
291
292 if (!bsearch_midx(oid, m, &pos))
293 return 0;
294
295 return nth_midxed_pack_entry(m, e, pos);
296 }
297
298 int midx_contains_pack(struct multi_pack_index *m, const char *idx_name)
299 {
300 uint32_t first = 0, last = m->num_packs;
301
302 while (first < last) {
303 uint32_t mid = first + (last - first) / 2;
304 const char *current;
305 int cmp;
306
307 current = m->pack_names[mid];
308 cmp = strcmp(idx_name, current);
309 if (!cmp)
310 return 1;
311 if (cmp > 0) {
312 first = mid + 1;
313 continue;
314 }
315 last = mid;
316 }
317
318 return 0;
319 }
320
321 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir)
322 {
323 struct multi_pack_index *m = r->objects->multi_pack_index;
324 struct multi_pack_index *m_search;
325 int config_value;
326
327 if (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
328 !config_value)
329 return 0;
330
331 for (m_search = m; m_search; m_search = m_search->next)
332 if (!strcmp(object_dir, m_search->object_dir))
333 return 1;
334
335 r->objects->multi_pack_index = load_multi_pack_index(object_dir);
336
337 if (r->objects->multi_pack_index) {
338 r->objects->multi_pack_index->next = m;
339 return 1;
340 }
341
342 return 0;
343 }
344
345 static size_t write_midx_header(struct hashfile *f,
346 unsigned char num_chunks,
347 uint32_t num_packs)
348 {
349 unsigned char byte_values[4];
350
351 hashwrite_be32(f, MIDX_SIGNATURE);
352 byte_values[0] = MIDX_VERSION;
353 byte_values[1] = MIDX_HASH_VERSION;
354 byte_values[2] = num_chunks;
355 byte_values[3] = 0; /* unused */
356 hashwrite(f, byte_values, sizeof(byte_values));
357 hashwrite_be32(f, num_packs);
358
359 return MIDX_HEADER_SIZE;
360 }
361
362 struct pack_list {
363 struct packed_git **list;
364 char **names;
365 uint32_t nr;
366 uint32_t alloc_list;
367 uint32_t alloc_names;
368 size_t pack_name_concat_len;
369 struct multi_pack_index *m;
370 };
371
372 static void add_pack_to_midx(const char *full_path, size_t full_path_len,
373 const char *file_name, void *data)
374 {
375 struct pack_list *packs = (struct pack_list *)data;
376
377 if (ends_with(file_name, ".idx")) {
378 if (packs->m && midx_contains_pack(packs->m, file_name))
379 return;
380
381 ALLOC_GROW(packs->list, packs->nr + 1, packs->alloc_list);
382 ALLOC_GROW(packs->names, packs->nr + 1, packs->alloc_names);
383
384 packs->list[packs->nr] = add_packed_git(full_path,
385 full_path_len,
386 0);
387
388 if (!packs->list[packs->nr]) {
389 warning(_("failed to add packfile '%s'"),
390 full_path);
391 return;
392 }
393
394 if (open_pack_index(packs->list[packs->nr])) {
395 warning(_("failed to open pack-index '%s'"),
396 full_path);
397 close_pack(packs->list[packs->nr]);
398 FREE_AND_NULL(packs->list[packs->nr]);
399 return;
400 }
401
402 packs->names[packs->nr] = xstrdup(file_name);
403 packs->pack_name_concat_len += strlen(file_name) + 1;
404 packs->nr++;
405 }
406 }
407
408 struct pack_pair {
409 uint32_t pack_int_id;
410 char *pack_name;
411 };
412
413 static int pack_pair_compare(const void *_a, const void *_b)
414 {
415 struct pack_pair *a = (struct pack_pair *)_a;
416 struct pack_pair *b = (struct pack_pair *)_b;
417 return strcmp(a->pack_name, b->pack_name);
418 }
419
420 static void sort_packs_by_name(char **pack_names, uint32_t nr_packs, uint32_t *perm)
421 {
422 uint32_t i;
423 struct pack_pair *pairs;
424
425 ALLOC_ARRAY(pairs, nr_packs);
426
427 for (i = 0; i < nr_packs; i++) {
428 pairs[i].pack_int_id = i;
429 pairs[i].pack_name = pack_names[i];
430 }
431
432 QSORT(pairs, nr_packs, pack_pair_compare);
433
434 for (i = 0; i < nr_packs; i++) {
435 pack_names[i] = pairs[i].pack_name;
436 perm[pairs[i].pack_int_id] = i;
437 }
438
439 free(pairs);
440 }
441
442 struct pack_midx_entry {
443 struct object_id oid;
444 uint32_t pack_int_id;
445 time_t pack_mtime;
446 uint64_t offset;
447 };
448
449 static int midx_oid_compare(const void *_a, const void *_b)
450 {
451 const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
452 const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
453 int cmp = oidcmp(&a->oid, &b->oid);
454
455 if (cmp)
456 return cmp;
457
458 if (a->pack_mtime > b->pack_mtime)
459 return -1;
460 else if (a->pack_mtime < b->pack_mtime)
461 return 1;
462
463 return a->pack_int_id - b->pack_int_id;
464 }
465
466 static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
467 uint32_t *pack_perm,
468 struct pack_midx_entry *e,
469 uint32_t pos)
470 {
471 if (pos >= m->num_objects)
472 return 1;
473
474 nth_midxed_object_oid(&e->oid, m, pos);
475 e->pack_int_id = pack_perm[nth_midxed_pack_int_id(m, pos)];
476 e->offset = nth_midxed_offset(m, pos);
477
478 /* consider objects in midx to be from "old" packs */
479 e->pack_mtime = 0;
480 return 0;
481 }
482
483 static void fill_pack_entry(uint32_t pack_int_id,
484 struct packed_git *p,
485 uint32_t cur_object,
486 struct pack_midx_entry *entry)
487 {
488 if (!nth_packed_object_oid(&entry->oid, p, cur_object))
489 die(_("failed to locate object %d in packfile"), cur_object);
490
491 entry->pack_int_id = pack_int_id;
492 entry->pack_mtime = p->mtime;
493
494 entry->offset = nth_packed_object_offset(p, cur_object);
495 }
496
497 /*
498 * It is possible to artificially get into a state where there are many
499 * duplicate copies of objects. That can create high memory pressure if
500 * we are to create a list of all objects before de-duplication. To reduce
501 * this memory pressure without a significant performance drop, automatically
502 * group objects by the first byte of their object id. Use the IDX fanout
503 * tables to group the data, copy to a local array, then sort.
504 *
505 * Copy only the de-duplicated entries (selected by most-recent modified time
506 * of a packfile containing the object).
507 */
508 static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
509 struct packed_git **p,
510 uint32_t *perm,
511 uint32_t nr_packs,
512 uint32_t *nr_objects)
513 {
514 uint32_t cur_fanout, cur_pack, cur_object;
515 uint32_t alloc_fanout, alloc_objects, total_objects = 0;
516 struct pack_midx_entry *entries_by_fanout = NULL;
517 struct pack_midx_entry *deduplicated_entries = NULL;
518 uint32_t start_pack = m ? m->num_packs : 0;
519
520 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
521 total_objects += p[cur_pack]->num_objects;
522
523 /*
524 * As we de-duplicate by fanout value, we expect the fanout
525 * slices to be evenly distributed, with some noise. Hence,
526 * allocate slightly more than one 256th.
527 */
528 alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
529
530 ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
531 ALLOC_ARRAY(deduplicated_entries, alloc_objects);
532 *nr_objects = 0;
533
534 for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
535 uint32_t nr_fanout = 0;
536
537 if (m) {
538 uint32_t start = 0, end;
539
540 if (cur_fanout)
541 start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
542 end = ntohl(m->chunk_oid_fanout[cur_fanout]);
543
544 for (cur_object = start; cur_object < end; cur_object++) {
545 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
546 nth_midxed_pack_midx_entry(m, perm,
547 &entries_by_fanout[nr_fanout],
548 cur_object);
549 nr_fanout++;
550 }
551 }
552
553 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
554 uint32_t start = 0, end;
555
556 if (cur_fanout)
557 start = get_pack_fanout(p[cur_pack], cur_fanout - 1);
558 end = get_pack_fanout(p[cur_pack], cur_fanout);
559
560 for (cur_object = start; cur_object < end; cur_object++) {
561 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
562 fill_pack_entry(perm[cur_pack], p[cur_pack], cur_object, &entries_by_fanout[nr_fanout]);
563 nr_fanout++;
564 }
565 }
566
567 QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
568
569 /*
570 * The batch is now sorted by OID and then mtime (descending).
571 * Take only the first duplicate.
572 */
573 for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
574 if (cur_object && !oidcmp(&entries_by_fanout[cur_object - 1].oid,
575 &entries_by_fanout[cur_object].oid))
576 continue;
577
578 ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
579 memcpy(&deduplicated_entries[*nr_objects],
580 &entries_by_fanout[cur_object],
581 sizeof(struct pack_midx_entry));
582 (*nr_objects)++;
583 }
584 }
585
586 free(entries_by_fanout);
587 return deduplicated_entries;
588 }
589
590 static size_t write_midx_pack_names(struct hashfile *f,
591 char **pack_names,
592 uint32_t num_packs)
593 {
594 uint32_t i;
595 unsigned char padding[MIDX_CHUNK_ALIGNMENT];
596 size_t written = 0;
597
598 for (i = 0; i < num_packs; i++) {
599 size_t writelen = strlen(pack_names[i]) + 1;
600
601 if (i && strcmp(pack_names[i], pack_names[i - 1]) <= 0)
602 BUG("incorrect pack-file order: %s before %s",
603 pack_names[i - 1],
604 pack_names[i]);
605
606 hashwrite(f, pack_names[i], writelen);
607 written += writelen;
608 }
609
610 /* add padding to be aligned */
611 i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
612 if (i < MIDX_CHUNK_ALIGNMENT) {
613 memset(padding, 0, sizeof(padding));
614 hashwrite(f, padding, i);
615 written += i;
616 }
617
618 return written;
619 }
620
621 static size_t write_midx_oid_fanout(struct hashfile *f,
622 struct pack_midx_entry *objects,
623 uint32_t nr_objects)
624 {
625 struct pack_midx_entry *list = objects;
626 struct pack_midx_entry *last = objects + nr_objects;
627 uint32_t count = 0;
628 uint32_t i;
629
630 /*
631 * Write the first-level table (the list is sorted,
632 * but we use a 256-entry lookup to be able to avoid
633 * having to do eight extra binary search iterations).
634 */
635 for (i = 0; i < 256; i++) {
636 struct pack_midx_entry *next = list;
637
638 while (next < last && next->oid.hash[0] == i) {
639 count++;
640 next++;
641 }
642
643 hashwrite_be32(f, count);
644 list = next;
645 }
646
647 return MIDX_CHUNK_FANOUT_SIZE;
648 }
649
650 static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
651 struct pack_midx_entry *objects,
652 uint32_t nr_objects)
653 {
654 struct pack_midx_entry *list = objects;
655 uint32_t i;
656 size_t written = 0;
657
658 for (i = 0; i < nr_objects; i++) {
659 struct pack_midx_entry *obj = list++;
660
661 if (i < nr_objects - 1) {
662 struct pack_midx_entry *next = list;
663 if (oidcmp(&obj->oid, &next->oid) >= 0)
664 BUG("OIDs not in order: %s >= %s",
665 oid_to_hex(&obj->oid),
666 oid_to_hex(&next->oid));
667 }
668
669 hashwrite(f, obj->oid.hash, (int)hash_len);
670 written += hash_len;
671 }
672
673 return written;
674 }
675
676 static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
677 struct pack_midx_entry *objects, uint32_t nr_objects)
678 {
679 struct pack_midx_entry *list = objects;
680 uint32_t i, nr_large_offset = 0;
681 size_t written = 0;
682
683 for (i = 0; i < nr_objects; i++) {
684 struct pack_midx_entry *obj = list++;
685
686 hashwrite_be32(f, obj->pack_int_id);
687
688 if (large_offset_needed && obj->offset >> 31)
689 hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
690 else if (!large_offset_needed && obj->offset >> 32)
691 BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
692 oid_to_hex(&obj->oid),
693 obj->offset);
694 else
695 hashwrite_be32(f, (uint32_t)obj->offset);
696
697 written += MIDX_CHUNK_OFFSET_WIDTH;
698 }
699
700 return written;
701 }
702
703 static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset,
704 struct pack_midx_entry *objects, uint32_t nr_objects)
705 {
706 struct pack_midx_entry *list = objects;
707 size_t written = 0;
708
709 while (nr_large_offset) {
710 struct pack_midx_entry *obj = list++;
711 uint64_t offset = obj->offset;
712
713 if (!(offset >> 31))
714 continue;
715
716 hashwrite_be32(f, offset >> 32);
717 hashwrite_be32(f, offset & 0xffffffffUL);
718 written += 2 * sizeof(uint32_t);
719
720 nr_large_offset--;
721 }
722
723 return written;
724 }
725
726 int write_midx_file(const char *object_dir)
727 {
728 unsigned char cur_chunk, num_chunks = 0;
729 char *midx_name;
730 uint32_t i;
731 struct hashfile *f = NULL;
732 struct lock_file lk;
733 struct pack_list packs;
734 uint32_t *pack_perm = NULL;
735 uint64_t written = 0;
736 uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1];
737 uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
738 uint32_t nr_entries, num_large_offsets = 0;
739 struct pack_midx_entry *entries = NULL;
740 int large_offsets_needed = 0;
741
742 midx_name = get_midx_filename(object_dir);
743 if (safe_create_leading_directories(midx_name)) {
744 UNLEAK(midx_name);
745 die_errno(_("unable to create leading directories of %s"),
746 midx_name);
747 }
748
749 packs.m = load_multi_pack_index(object_dir);
750
751 packs.nr = 0;
752 packs.alloc_list = packs.m ? packs.m->num_packs : 16;
753 packs.alloc_names = packs.alloc_list;
754 packs.list = NULL;
755 packs.names = NULL;
756 packs.pack_name_concat_len = 0;
757 ALLOC_ARRAY(packs.list, packs.alloc_list);
758 ALLOC_ARRAY(packs.names, packs.alloc_names);
759
760 if (packs.m) {
761 for (i = 0; i < packs.m->num_packs; i++) {
762 ALLOC_GROW(packs.list, packs.nr + 1, packs.alloc_list);
763 ALLOC_GROW(packs.names, packs.nr + 1, packs.alloc_names);
764
765 packs.list[packs.nr] = NULL;
766 packs.names[packs.nr] = xstrdup(packs.m->pack_names[i]);
767 packs.pack_name_concat_len += strlen(packs.names[packs.nr]) + 1;
768 packs.nr++;
769 }
770 }
771
772 for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
773
774 if (packs.m && packs.nr == packs.m->num_packs)
775 goto cleanup;
776
777 if (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
778 packs.pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
779 (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
780
781 ALLOC_ARRAY(pack_perm, packs.nr);
782 sort_packs_by_name(packs.names, packs.nr, pack_perm);
783
784 entries = get_sorted_entries(packs.m, packs.list, pack_perm, packs.nr, &nr_entries);
785
786 for (i = 0; i < nr_entries; i++) {
787 if (entries[i].offset > 0x7fffffff)
788 num_large_offsets++;
789 if (entries[i].offset > 0xffffffff)
790 large_offsets_needed = 1;
791 }
792
793 hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
794 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
795 FREE_AND_NULL(midx_name);
796
797 if (packs.m)
798 close_midx(packs.m);
799
800 cur_chunk = 0;
801 num_chunks = large_offsets_needed ? 5 : 4;
802
803 written = write_midx_header(f, num_chunks, packs.nr);
804
805 chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES;
806 chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
807
808 cur_chunk++;
809 chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT;
810 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len;
811
812 cur_chunk++;
813 chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
814 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE;
815
816 cur_chunk++;
817 chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
818 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN;
819
820 cur_chunk++;
821 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
822 if (large_offsets_needed) {
823 chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS;
824
825 cur_chunk++;
826 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] +
827 num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH;
828 }
829
830 chunk_ids[cur_chunk] = 0;
831
832 for (i = 0; i <= num_chunks; i++) {
833 if (i && chunk_offsets[i] < chunk_offsets[i - 1])
834 BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
835 chunk_offsets[i - 1],
836 chunk_offsets[i]);
837
838 if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT)
839 BUG("chunk offset %"PRIu64" is not properly aligned",
840 chunk_offsets[i]);
841
842 hashwrite_be32(f, chunk_ids[i]);
843 hashwrite_be32(f, chunk_offsets[i] >> 32);
844 hashwrite_be32(f, chunk_offsets[i]);
845
846 written += MIDX_CHUNKLOOKUP_WIDTH;
847 }
848
849 for (i = 0; i < num_chunks; i++) {
850 if (written != chunk_offsets[i])
851 BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
852 chunk_offsets[i],
853 written,
854 chunk_ids[i]);
855
856 switch (chunk_ids[i]) {
857 case MIDX_CHUNKID_PACKNAMES:
858 written += write_midx_pack_names(f, packs.names, packs.nr);
859 break;
860
861 case MIDX_CHUNKID_OIDFANOUT:
862 written += write_midx_oid_fanout(f, entries, nr_entries);
863 break;
864
865 case MIDX_CHUNKID_OIDLOOKUP:
866 written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries);
867 break;
868
869 case MIDX_CHUNKID_OBJECTOFFSETS:
870 written += write_midx_object_offsets(f, large_offsets_needed, entries, nr_entries);
871 break;
872
873 case MIDX_CHUNKID_LARGEOFFSETS:
874 written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries);
875 break;
876
877 default:
878 BUG("trying to write unknown chunk id %"PRIx32,
879 chunk_ids[i]);
880 }
881 }
882
883 if (written != chunk_offsets[num_chunks])
884 BUG("incorrect final offset %"PRIu64" != %"PRIu64,
885 written,
886 chunk_offsets[num_chunks]);
887
888 finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
889 commit_lock_file(&lk);
890
891 cleanup:
892 for (i = 0; i < packs.nr; i++) {
893 if (packs.list[i]) {
894 close_pack(packs.list[i]);
895 free(packs.list[i]);
896 }
897 free(packs.names[i]);
898 }
899
900 free(packs.list);
901 free(packs.names);
902 free(entries);
903 free(pack_perm);
904 free(midx_name);
905 return 0;
906 }