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
35static char *get_midx_filename(const char *object_dir)
36{
37 return xstrfmt("%s/pack/multi-pack-index", object_dir);
38}
39
40struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
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 m->local = local;
77
78 m->signature = get_be32(m->data);
79 if (m->signature != MIDX_SIGNATURE) {
80 error(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
81 m->signature, MIDX_SIGNATURE);
82 goto cleanup_fail;
83 }
84
85 m->version = m->data[MIDX_BYTE_FILE_VERSION];
86 if (m->version != MIDX_VERSION) {
87 error(_("multi-pack-index version %d not recognized"),
88 m->version);
89 goto cleanup_fail;
90 }
91
92 hash_version = m->data[MIDX_BYTE_HASH_VERSION];
93 if (hash_version != MIDX_HASH_VERSION) {
94 error(_("hash version %u does not match"), hash_version);
95 goto cleanup_fail;
96 }
97 m->hash_len = MIDX_HASH_LEN;
98
99 m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
100
101 m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
102
103 for (i = 0; i < m->num_chunks; i++) {
104 uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
105 MIDX_CHUNKLOOKUP_WIDTH * i);
106 uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
107 MIDX_CHUNKLOOKUP_WIDTH * i);
108
109 switch (chunk_id) {
110 case MIDX_CHUNKID_PACKNAMES:
111 m->chunk_pack_names = m->data + chunk_offset;
112 break;
113
114 case MIDX_CHUNKID_OIDFANOUT:
115 m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset);
116 break;
117
118 case MIDX_CHUNKID_OIDLOOKUP:
119 m->chunk_oid_lookup = m->data + chunk_offset;
120 break;
121
122 case MIDX_CHUNKID_OBJECTOFFSETS:
123 m->chunk_object_offsets = m->data + chunk_offset;
124 break;
125
126 case MIDX_CHUNKID_LARGEOFFSETS:
127 m->chunk_large_offsets = m->data + chunk_offset;
128 break;
129
130 case 0:
131 die(_("terminating multi-pack-index chunk id appears earlier than expected"));
132 break;
133
134 default:
135 /*
136 * Do nothing on unrecognized chunks, allowing future
137 * extensions to add optional chunks.
138 */
139 break;
140 }
141 }
142
143 if (!m->chunk_pack_names)
144 die(_("multi-pack-index missing required pack-name chunk"));
145 if (!m->chunk_oid_fanout)
146 die(_("multi-pack-index missing required OID fanout chunk"));
147 if (!m->chunk_oid_lookup)
148 die(_("multi-pack-index missing required OID lookup chunk"));
149 if (!m->chunk_object_offsets)
150 die(_("multi-pack-index missing required object offsets chunk"));
151
152 m->num_objects = ntohl(m->chunk_oid_fanout[255]);
153
154 m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
155 m->packs = xcalloc(m->num_packs, sizeof(*m->packs));
156
157 cur_pack_name = (const char *)m->chunk_pack_names;
158 for (i = 0; i < m->num_packs; i++) {
159 m->pack_names[i] = cur_pack_name;
160
161 cur_pack_name += strlen(cur_pack_name) + 1;
162
163 if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0) {
164 error(_("multi-pack-index pack names out of order: '%s' before '%s'"),
165 m->pack_names[i - 1],
166 m->pack_names[i]);
167 goto cleanup_fail;
168 }
169 }
170
171 return m;
172
173cleanup_fail:
174 free(m);
175 free(midx_name);
176 if (midx_map)
177 munmap(midx_map, midx_size);
178 if (0 <= fd)
179 close(fd);
180 return NULL;
181}
182
183void close_midx(struct multi_pack_index *m)
184{
185 uint32_t i;
186
187 if (!m)
188 return;
189
190 munmap((unsigned char *)m->data, m->data_len);
191 close(m->fd);
192 m->fd = -1;
193
194 for (i = 0; i < m->num_packs; i++) {
195 if (m->packs[i]) {
196 close_pack(m->packs[i]);
197 free(m->packs[i]);
198 }
199 }
200 FREE_AND_NULL(m->packs);
201 FREE_AND_NULL(m->pack_names);
202}
203
204int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
205{
206 struct strbuf pack_name = STRBUF_INIT;
207
208 if (pack_int_id >= m->num_packs)
209 BUG("bad pack-int-id");
210
211 if (m->packs[pack_int_id])
212 return 0;
213
214 strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
215 m->pack_names[pack_int_id]);
216
217 m->packs[pack_int_id] = add_packed_git(pack_name.buf, pack_name.len, m->local);
218 strbuf_release(&pack_name);
219 return !m->packs[pack_int_id];
220}
221
222int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
223{
224 return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
225 MIDX_HASH_LEN, result);
226}
227
228struct object_id *nth_midxed_object_oid(struct object_id *oid,
229 struct multi_pack_index *m,
230 uint32_t n)
231{
232 if (n >= m->num_objects)
233 return NULL;
234
235 hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
236 return oid;
237}
238
239static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
240{
241 const unsigned char *offset_data;
242 uint32_t offset32;
243
244 offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH;
245 offset32 = get_be32(offset_data + sizeof(uint32_t));
246
247 if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
248 if (sizeof(offset32) < sizeof(uint64_t))
249 die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
250
251 offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
252 return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
253 }
254
255 return offset32;
256}
257
258static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
259{
260 return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH);
261}
262
263static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *e, uint32_t pos)
264{
265 uint32_t pack_int_id;
266 struct packed_git *p;
267
268 if (pos >= m->num_objects)
269 return 0;
270
271 pack_int_id = nth_midxed_pack_int_id(m, pos);
272
273 if (prepare_midx_pack(m, pack_int_id))
274 die(_("error preparing packfile from multi-pack-index"));
275 p = m->packs[pack_int_id];
276
277 /*
278 * We are about to tell the caller where they can locate the
279 * requested object. We better make sure the packfile is
280 * still here and can be accessed before supplying that
281 * answer, as it may have been deleted since the MIDX was
282 * loaded!
283 */
284 if (!is_pack_valid(p))
285 return 0;
286
287 if (p->num_bad_objects) {
288 uint32_t i;
289 struct object_id oid;
290 nth_midxed_object_oid(&oid, m, pos);
291 for (i = 0; i < p->num_bad_objects; i++)
292 if (!hashcmp(oid.hash,
293 p->bad_object_sha1 + the_hash_algo->rawsz * i))
294 return 0;
295 }
296
297 e->offset = nth_midxed_offset(m, pos);
298 e->p = p;
299
300 return 1;
301}
302
303int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m)
304{
305 uint32_t pos;
306
307 if (!bsearch_midx(oid, m, &pos))
308 return 0;
309
310 return nth_midxed_pack_entry(m, e, pos);
311}
312
313int midx_contains_pack(struct multi_pack_index *m, const char *idx_name)
314{
315 uint32_t first = 0, last = m->num_packs;
316
317 while (first < last) {
318 uint32_t mid = first + (last - first) / 2;
319 const char *current;
320 int cmp;
321
322 current = m->pack_names[mid];
323 cmp = strcmp(idx_name, current);
324 if (!cmp)
325 return 1;
326 if (cmp > 0) {
327 first = mid + 1;
328 continue;
329 }
330 last = mid;
331 }
332
333 return 0;
334}
335
336int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local)
337{
338 struct multi_pack_index *m;
339 struct multi_pack_index *m_search;
340 int config_value;
341 static int env_value = -1;
342
343 if (env_value < 0)
344 env_value = git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0);
345
346 if (!env_value &&
347 (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
348 !config_value))
349 return 0;
350
351 for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
352 if (!strcmp(object_dir, m_search->object_dir))
353 return 1;
354
355 m = load_multi_pack_index(object_dir, local);
356
357 if (m) {
358 m->next = r->objects->multi_pack_index;
359 r->objects->multi_pack_index = m;
360 return 1;
361 }
362
363 return 0;
364}
365
366static size_t write_midx_header(struct hashfile *f,
367 unsigned char num_chunks,
368 uint32_t num_packs)
369{
370 unsigned char byte_values[4];
371
372 hashwrite_be32(f, MIDX_SIGNATURE);
373 byte_values[0] = MIDX_VERSION;
374 byte_values[1] = MIDX_HASH_VERSION;
375 byte_values[2] = num_chunks;
376 byte_values[3] = 0; /* unused */
377 hashwrite(f, byte_values, sizeof(byte_values));
378 hashwrite_be32(f, num_packs);
379
380 return MIDX_HEADER_SIZE;
381}
382
383struct pack_list {
384 struct packed_git **list;
385 char **names;
386 uint32_t nr;
387 uint32_t alloc_list;
388 uint32_t alloc_names;
389 size_t pack_name_concat_len;
390 struct multi_pack_index *m;
391};
392
393static void add_pack_to_midx(const char *full_path, size_t full_path_len,
394 const char *file_name, void *data)
395{
396 struct pack_list *packs = (struct pack_list *)data;
397
398 if (ends_with(file_name, ".idx")) {
399 if (packs->m && midx_contains_pack(packs->m, file_name))
400 return;
401
402 ALLOC_GROW(packs->list, packs->nr + 1, packs->alloc_list);
403 ALLOC_GROW(packs->names, packs->nr + 1, packs->alloc_names);
404
405 packs->list[packs->nr] = add_packed_git(full_path,
406 full_path_len,
407 0);
408
409 if (!packs->list[packs->nr]) {
410 warning(_("failed to add packfile '%s'"),
411 full_path);
412 return;
413 }
414
415 if (open_pack_index(packs->list[packs->nr])) {
416 warning(_("failed to open pack-index '%s'"),
417 full_path);
418 close_pack(packs->list[packs->nr]);
419 FREE_AND_NULL(packs->list[packs->nr]);
420 return;
421 }
422
423 packs->names[packs->nr] = xstrdup(file_name);
424 packs->pack_name_concat_len += strlen(file_name) + 1;
425 packs->nr++;
426 }
427}
428
429struct pack_pair {
430 uint32_t pack_int_id;
431 char *pack_name;
432};
433
434static int pack_pair_compare(const void *_a, const void *_b)
435{
436 struct pack_pair *a = (struct pack_pair *)_a;
437 struct pack_pair *b = (struct pack_pair *)_b;
438 return strcmp(a->pack_name, b->pack_name);
439}
440
441static void sort_packs_by_name(char **pack_names, uint32_t nr_packs, uint32_t *perm)
442{
443 uint32_t i;
444 struct pack_pair *pairs;
445
446 ALLOC_ARRAY(pairs, nr_packs);
447
448 for (i = 0; i < nr_packs; i++) {
449 pairs[i].pack_int_id = i;
450 pairs[i].pack_name = pack_names[i];
451 }
452
453 QSORT(pairs, nr_packs, pack_pair_compare);
454
455 for (i = 0; i < nr_packs; i++) {
456 pack_names[i] = pairs[i].pack_name;
457 perm[pairs[i].pack_int_id] = i;
458 }
459
460 free(pairs);
461}
462
463struct pack_midx_entry {
464 struct object_id oid;
465 uint32_t pack_int_id;
466 time_t pack_mtime;
467 uint64_t offset;
468};
469
470static int midx_oid_compare(const void *_a, const void *_b)
471{
472 const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
473 const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
474 int cmp = oidcmp(&a->oid, &b->oid);
475
476 if (cmp)
477 return cmp;
478
479 if (a->pack_mtime > b->pack_mtime)
480 return -1;
481 else if (a->pack_mtime < b->pack_mtime)
482 return 1;
483
484 return a->pack_int_id - b->pack_int_id;
485}
486
487static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
488 uint32_t *pack_perm,
489 struct pack_midx_entry *e,
490 uint32_t pos)
491{
492 if (pos >= m->num_objects)
493 return 1;
494
495 nth_midxed_object_oid(&e->oid, m, pos);
496 e->pack_int_id = pack_perm[nth_midxed_pack_int_id(m, pos)];
497 e->offset = nth_midxed_offset(m, pos);
498
499 /* consider objects in midx to be from "old" packs */
500 e->pack_mtime = 0;
501 return 0;
502}
503
504static void fill_pack_entry(uint32_t pack_int_id,
505 struct packed_git *p,
506 uint32_t cur_object,
507 struct pack_midx_entry *entry)
508{
509 if (!nth_packed_object_oid(&entry->oid, p, cur_object))
510 die(_("failed to locate object %d in packfile"), cur_object);
511
512 entry->pack_int_id = pack_int_id;
513 entry->pack_mtime = p->mtime;
514
515 entry->offset = nth_packed_object_offset(p, cur_object);
516}
517
518/*
519 * It is possible to artificially get into a state where there are many
520 * duplicate copies of objects. That can create high memory pressure if
521 * we are to create a list of all objects before de-duplication. To reduce
522 * this memory pressure without a significant performance drop, automatically
523 * group objects by the first byte of their object id. Use the IDX fanout
524 * tables to group the data, copy to a local array, then sort.
525 *
526 * Copy only the de-duplicated entries (selected by most-recent modified time
527 * of a packfile containing the object).
528 */
529static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
530 struct packed_git **p,
531 uint32_t *perm,
532 uint32_t nr_packs,
533 uint32_t *nr_objects)
534{
535 uint32_t cur_fanout, cur_pack, cur_object;
536 uint32_t alloc_fanout, alloc_objects, total_objects = 0;
537 struct pack_midx_entry *entries_by_fanout = NULL;
538 struct pack_midx_entry *deduplicated_entries = NULL;
539 uint32_t start_pack = m ? m->num_packs : 0;
540
541 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
542 total_objects += p[cur_pack]->num_objects;
543
544 /*
545 * As we de-duplicate by fanout value, we expect the fanout
546 * slices to be evenly distributed, with some noise. Hence,
547 * allocate slightly more than one 256th.
548 */
549 alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
550
551 ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
552 ALLOC_ARRAY(deduplicated_entries, alloc_objects);
553 *nr_objects = 0;
554
555 for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
556 uint32_t nr_fanout = 0;
557
558 if (m) {
559 uint32_t start = 0, end;
560
561 if (cur_fanout)
562 start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
563 end = ntohl(m->chunk_oid_fanout[cur_fanout]);
564
565 for (cur_object = start; cur_object < end; cur_object++) {
566 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
567 nth_midxed_pack_midx_entry(m, perm,
568 &entries_by_fanout[nr_fanout],
569 cur_object);
570 nr_fanout++;
571 }
572 }
573
574 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
575 uint32_t start = 0, end;
576
577 if (cur_fanout)
578 start = get_pack_fanout(p[cur_pack], cur_fanout - 1);
579 end = get_pack_fanout(p[cur_pack], cur_fanout);
580
581 for (cur_object = start; cur_object < end; cur_object++) {
582 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
583 fill_pack_entry(perm[cur_pack], p[cur_pack], cur_object, &entries_by_fanout[nr_fanout]);
584 nr_fanout++;
585 }
586 }
587
588 QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
589
590 /*
591 * The batch is now sorted by OID and then mtime (descending).
592 * Take only the first duplicate.
593 */
594 for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
595 if (cur_object && !oidcmp(&entries_by_fanout[cur_object - 1].oid,
596 &entries_by_fanout[cur_object].oid))
597 continue;
598
599 ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
600 memcpy(&deduplicated_entries[*nr_objects],
601 &entries_by_fanout[cur_object],
602 sizeof(struct pack_midx_entry));
603 (*nr_objects)++;
604 }
605 }
606
607 free(entries_by_fanout);
608 return deduplicated_entries;
609}
610
611static size_t write_midx_pack_names(struct hashfile *f,
612 char **pack_names,
613 uint32_t num_packs)
614{
615 uint32_t i;
616 unsigned char padding[MIDX_CHUNK_ALIGNMENT];
617 size_t written = 0;
618
619 for (i = 0; i < num_packs; i++) {
620 size_t writelen = strlen(pack_names[i]) + 1;
621
622 if (i && strcmp(pack_names[i], pack_names[i - 1]) <= 0)
623 BUG("incorrect pack-file order: %s before %s",
624 pack_names[i - 1],
625 pack_names[i]);
626
627 hashwrite(f, pack_names[i], writelen);
628 written += writelen;
629 }
630
631 /* add padding to be aligned */
632 i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
633 if (i < MIDX_CHUNK_ALIGNMENT) {
634 memset(padding, 0, sizeof(padding));
635 hashwrite(f, padding, i);
636 written += i;
637 }
638
639 return written;
640}
641
642static size_t write_midx_oid_fanout(struct hashfile *f,
643 struct pack_midx_entry *objects,
644 uint32_t nr_objects)
645{
646 struct pack_midx_entry *list = objects;
647 struct pack_midx_entry *last = objects + nr_objects;
648 uint32_t count = 0;
649 uint32_t i;
650
651 /*
652 * Write the first-level table (the list is sorted,
653 * but we use a 256-entry lookup to be able to avoid
654 * having to do eight extra binary search iterations).
655 */
656 for (i = 0; i < 256; i++) {
657 struct pack_midx_entry *next = list;
658
659 while (next < last && next->oid.hash[0] == i) {
660 count++;
661 next++;
662 }
663
664 hashwrite_be32(f, count);
665 list = next;
666 }
667
668 return MIDX_CHUNK_FANOUT_SIZE;
669}
670
671static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
672 struct pack_midx_entry *objects,
673 uint32_t nr_objects)
674{
675 struct pack_midx_entry *list = objects;
676 uint32_t i;
677 size_t written = 0;
678
679 for (i = 0; i < nr_objects; i++) {
680 struct pack_midx_entry *obj = list++;
681
682 if (i < nr_objects - 1) {
683 struct pack_midx_entry *next = list;
684 if (oidcmp(&obj->oid, &next->oid) >= 0)
685 BUG("OIDs not in order: %s >= %s",
686 oid_to_hex(&obj->oid),
687 oid_to_hex(&next->oid));
688 }
689
690 hashwrite(f, obj->oid.hash, (int)hash_len);
691 written += hash_len;
692 }
693
694 return written;
695}
696
697static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
698 struct pack_midx_entry *objects, uint32_t nr_objects)
699{
700 struct pack_midx_entry *list = objects;
701 uint32_t i, nr_large_offset = 0;
702 size_t written = 0;
703
704 for (i = 0; i < nr_objects; i++) {
705 struct pack_midx_entry *obj = list++;
706
707 hashwrite_be32(f, obj->pack_int_id);
708
709 if (large_offset_needed && obj->offset >> 31)
710 hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
711 else if (!large_offset_needed && obj->offset >> 32)
712 BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
713 oid_to_hex(&obj->oid),
714 obj->offset);
715 else
716 hashwrite_be32(f, (uint32_t)obj->offset);
717
718 written += MIDX_CHUNK_OFFSET_WIDTH;
719 }
720
721 return written;
722}
723
724static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset,
725 struct pack_midx_entry *objects, uint32_t nr_objects)
726{
727 struct pack_midx_entry *list = objects;
728 size_t written = 0;
729
730 while (nr_large_offset) {
731 struct pack_midx_entry *obj = list++;
732 uint64_t offset = obj->offset;
733
734 if (!(offset >> 31))
735 continue;
736
737 hashwrite_be32(f, offset >> 32);
738 hashwrite_be32(f, offset & 0xffffffffUL);
739 written += 2 * sizeof(uint32_t);
740
741 nr_large_offset--;
742 }
743
744 return written;
745}
746
747int write_midx_file(const char *object_dir)
748{
749 unsigned char cur_chunk, num_chunks = 0;
750 char *midx_name;
751 uint32_t i;
752 struct hashfile *f = NULL;
753 struct lock_file lk;
754 struct pack_list packs;
755 uint32_t *pack_perm = NULL;
756 uint64_t written = 0;
757 uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1];
758 uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
759 uint32_t nr_entries, num_large_offsets = 0;
760 struct pack_midx_entry *entries = NULL;
761 int large_offsets_needed = 0;
762
763 midx_name = get_midx_filename(object_dir);
764 if (safe_create_leading_directories(midx_name)) {
765 UNLEAK(midx_name);
766 die_errno(_("unable to create leading directories of %s"),
767 midx_name);
768 }
769
770 packs.m = load_multi_pack_index(object_dir, 1);
771
772 packs.nr = 0;
773 packs.alloc_list = packs.m ? packs.m->num_packs : 16;
774 packs.alloc_names = packs.alloc_list;
775 packs.list = NULL;
776 packs.names = NULL;
777 packs.pack_name_concat_len = 0;
778 ALLOC_ARRAY(packs.list, packs.alloc_list);
779 ALLOC_ARRAY(packs.names, packs.alloc_names);
780
781 if (packs.m) {
782 for (i = 0; i < packs.m->num_packs; i++) {
783 ALLOC_GROW(packs.list, packs.nr + 1, packs.alloc_list);
784 ALLOC_GROW(packs.names, packs.nr + 1, packs.alloc_names);
785
786 packs.list[packs.nr] = NULL;
787 packs.names[packs.nr] = xstrdup(packs.m->pack_names[i]);
788 packs.pack_name_concat_len += strlen(packs.names[packs.nr]) + 1;
789 packs.nr++;
790 }
791 }
792
793 for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
794
795 if (packs.m && packs.nr == packs.m->num_packs)
796 goto cleanup;
797
798 if (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
799 packs.pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
800 (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
801
802 ALLOC_ARRAY(pack_perm, packs.nr);
803 sort_packs_by_name(packs.names, packs.nr, pack_perm);
804
805 entries = get_sorted_entries(packs.m, packs.list, pack_perm, packs.nr, &nr_entries);
806
807 for (i = 0; i < nr_entries; i++) {
808 if (entries[i].offset > 0x7fffffff)
809 num_large_offsets++;
810 if (entries[i].offset > 0xffffffff)
811 large_offsets_needed = 1;
812 }
813
814 hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
815 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
816 FREE_AND_NULL(midx_name);
817
818 if (packs.m)
819 close_midx(packs.m);
820
821 cur_chunk = 0;
822 num_chunks = large_offsets_needed ? 5 : 4;
823
824 written = write_midx_header(f, num_chunks, packs.nr);
825
826 chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES;
827 chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
828
829 cur_chunk++;
830 chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT;
831 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len;
832
833 cur_chunk++;
834 chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
835 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE;
836
837 cur_chunk++;
838 chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
839 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN;
840
841 cur_chunk++;
842 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
843 if (large_offsets_needed) {
844 chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS;
845
846 cur_chunk++;
847 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] +
848 num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH;
849 }
850
851 chunk_ids[cur_chunk] = 0;
852
853 for (i = 0; i <= num_chunks; i++) {
854 if (i && chunk_offsets[i] < chunk_offsets[i - 1])
855 BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
856 chunk_offsets[i - 1],
857 chunk_offsets[i]);
858
859 if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT)
860 BUG("chunk offset %"PRIu64" is not properly aligned",
861 chunk_offsets[i]);
862
863 hashwrite_be32(f, chunk_ids[i]);
864 hashwrite_be32(f, chunk_offsets[i] >> 32);
865 hashwrite_be32(f, chunk_offsets[i]);
866
867 written += MIDX_CHUNKLOOKUP_WIDTH;
868 }
869
870 for (i = 0; i < num_chunks; i++) {
871 if (written != chunk_offsets[i])
872 BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
873 chunk_offsets[i],
874 written,
875 chunk_ids[i]);
876
877 switch (chunk_ids[i]) {
878 case MIDX_CHUNKID_PACKNAMES:
879 written += write_midx_pack_names(f, packs.names, packs.nr);
880 break;
881
882 case MIDX_CHUNKID_OIDFANOUT:
883 written += write_midx_oid_fanout(f, entries, nr_entries);
884 break;
885
886 case MIDX_CHUNKID_OIDLOOKUP:
887 written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries);
888 break;
889
890 case MIDX_CHUNKID_OBJECTOFFSETS:
891 written += write_midx_object_offsets(f, large_offsets_needed, entries, nr_entries);
892 break;
893
894 case MIDX_CHUNKID_LARGEOFFSETS:
895 written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries);
896 break;
897
898 default:
899 BUG("trying to write unknown chunk id %"PRIx32,
900 chunk_ids[i]);
901 }
902 }
903
904 if (written != chunk_offsets[num_chunks])
905 BUG("incorrect final offset %"PRIu64" != %"PRIu64,
906 written,
907 chunk_offsets[num_chunks]);
908
909 finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
910 commit_lock_file(&lk);
911
912cleanup:
913 for (i = 0; i < packs.nr; i++) {
914 if (packs.list[i]) {
915 close_pack(packs.list[i]);
916 free(packs.list[i]);
917 }
918 free(packs.names[i]);
919 }
920
921 free(packs.list);
922 free(packs.names);
923 free(entries);
924 free(pack_perm);
925 free(midx_name);
926 return 0;
927}
928
929void clear_midx_file(struct repository *r)
930{
931 char *midx = get_midx_filename(r->objects->objectdir);
932
933 if (r->objects && r->objects->multi_pack_index) {
934 close_midx(r->objects->multi_pack_index);
935 r->objects->multi_pack_index = NULL;
936 }
937
938 if (remove_path(midx)) {
939 UNLEAK(midx);
940 die(_("failed to clear multi-pack-index at %s"), midx);
941 }
942
943 free(midx);
944}