git.oblomov.eu Git - git/blob - 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 #include "progress.h"
  11
  12 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
  13 #define MIDX_VERSION 1
  14 #define MIDX_BYTE_FILE_VERSION 4
  15 #define MIDX_BYTE_HASH_VERSION 5
  16 #define MIDX_BYTE_NUM_CHUNKS 6
  17 #define MIDX_BYTE_NUM_PACKS 8
  18 #define MIDX_HASH_VERSION 1
  19 #define MIDX_HEADER_SIZE 12
  20 #define MIDX_HASH_LEN 20
  21 #define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN)
  22
  23 #define MIDX_MAX_CHUNKS 5
  24 #define MIDX_CHUNK_ALIGNMENT 4
  25 #define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
  26 #define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  27 #define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  28 #define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
  29 #define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
  30 #define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
  31 #define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
  32 #define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
  33 #define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
  34 #define MIDX_LARGE_OFFSET_NEEDED 0x80000000
  35
  36 static char *get_midx_filename(const char *object_dir)
  37 {
  38         return xstrfmt("%s/pack/multi-pack-index", object_dir);
  39 }
  40
  41 struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
  42 {
  43         struct multi_pack_index *m = NULL;
  44         int fd;
  45         struct stat st;
  46         size_t midx_size;
  47         void *midx_map = NULL;
  48         uint32_t hash_version;
  49         char *midx_name = get_midx_filename(object_dir);
  50         uint32_t i;
  51         const char *cur_pack_name;
  52
  53         fd = git_open(midx_name);
  54
  55         if (fd < 0)
  56                 goto cleanup_fail;
  57         if (fstat(fd, &st)) {
  58                 error_errno(_("failed to read %s"), midx_name);
  59                 goto cleanup_fail;
  60         }
  61
  62         midx_size = xsize_t(st.st_size);
  63
  64         if (midx_size < MIDX_MIN_SIZE) {
  65                 error(_("multi-pack-index file %s is too small"), midx_name);
  66                 goto cleanup_fail;
  67         }
  68
  69         FREE_AND_NULL(midx_name);
  70
  71         midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
  72
  73         FLEX_ALLOC_MEM(m, object_dir, object_dir, strlen(object_dir));
  74         m->fd = fd;
  75         m->data = midx_map;
  76         m->data_len = midx_size;
  77         m->local = local;
  78
  79         m->signature = get_be32(m->data);
  80         if (m->signature != MIDX_SIGNATURE)
  81                 die(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
  82                       m->signature, MIDX_SIGNATURE);
  83
  84         m->version = m->data[MIDX_BYTE_FILE_VERSION];
  85         if (m->version != MIDX_VERSION)
  86                 die(_("multi-pack-index version %d not recognized"),
  87                       m->version);
  88
  89         hash_version = m->data[MIDX_BYTE_HASH_VERSION];
  90         if (hash_version != MIDX_HASH_VERSION)
  91                 die(_("hash version %u does not match"), hash_version);
  92         m->hash_len = MIDX_HASH_LEN;
  93
  94         m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
  95
  96         m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
  97
  98         for (i = 0; i < m->num_chunks; i++) {
  99                 uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
 100                                              MIDX_CHUNKLOOKUP_WIDTH * i);
 101                 uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
 102                                                  MIDX_CHUNKLOOKUP_WIDTH * i);
 103
 104                 if (chunk_offset >= m->data_len)
 105                         die(_("invalid chunk offset (too large)"));
 106
 107                 switch (chunk_id) {
 108                         case MIDX_CHUNKID_PACKNAMES:
 109                                 m->chunk_pack_names = m->data + chunk_offset;
 110                                 break;
 111
 112                         case MIDX_CHUNKID_OIDFANOUT:
 113                                 m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset);
 114                                 break;
 115
 116                         case MIDX_CHUNKID_OIDLOOKUP:
 117                                 m->chunk_oid_lookup = m->data + chunk_offset;
 118                                 break;
 119
 120                         case MIDX_CHUNKID_OBJECTOFFSETS:
 121                                 m->chunk_object_offsets = m->data + chunk_offset;
 122                                 break;
 123
 124                         case MIDX_CHUNKID_LARGEOFFSETS:
 125                                 m->chunk_large_offsets = m->data + chunk_offset;
 126                                 break;
 127
 128                         case 0:
 129                                 die(_("terminating multi-pack-index chunk id appears earlier than expected"));
 130                                 break;
 131
 132                         default:
 133                                 /*
 134                                  * Do nothing on unrecognized chunks, allowing future
 135                                  * extensions to add optional chunks.
 136                                  */
 137                                 break;
 138                 }
 139         }
 140
 141         if (!m->chunk_pack_names)
 142                 die(_("multi-pack-index missing required pack-name chunk"));
 143         if (!m->chunk_oid_fanout)
 144                 die(_("multi-pack-index missing required OID fanout chunk"));
 145         if (!m->chunk_oid_lookup)
 146                 die(_("multi-pack-index missing required OID lookup chunk"));
 147         if (!m->chunk_object_offsets)
 148                 die(_("multi-pack-index missing required object offsets chunk"));
 149
 150         m->num_objects = ntohl(m->chunk_oid_fanout[255]);
 151
 152         m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
 153         m->packs = xcalloc(m->num_packs, sizeof(*m->packs));
 154
 155         cur_pack_name = (const char *)m->chunk_pack_names;
 156         for (i = 0; i < m->num_packs; i++) {
 157                 m->pack_names[i] = cur_pack_name;
 158
 159                 cur_pack_name += strlen(cur_pack_name) + 1;
 160
 161                 if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0)
 162                         die(_("multi-pack-index pack names out of order: '%s' before '%s'"),
 163                               m->pack_names[i - 1],
 164                               m->pack_names[i]);
 165         }
 166
 167         return m;
 168
 169 cleanup_fail:
 170         free(m);
 171         free(midx_name);
 172         if (midx_map)
 173                 munmap(midx_map, midx_size);
 174         if (0 <= fd)
 175                 close(fd);
 176         return NULL;
 177 }
 178
 179 void close_midx(struct multi_pack_index *m)
 180 {
 181         uint32_t i;
 182
 183         if (!m)
 184                 return;
 185
 186         munmap((unsigned char *)m->data, m->data_len);
 187         close(m->fd);
 188         m->fd = -1;
 189
 190         for (i = 0; i < m->num_packs; i++) {
 191                 if (m->packs[i]) {
 192                         close_pack(m->packs[i]);
 193                         free(m->packs[i]);
 194                 }
 195         }
 196         FREE_AND_NULL(m->packs);
 197         FREE_AND_NULL(m->pack_names);
 198 }
 199
 200 int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
 201 {
 202         struct strbuf pack_name = STRBUF_INIT;
 203
 204         if (pack_int_id >= m->num_packs)
 205                 die(_("bad pack-int-id: %u (%u total packs"),
 206                     pack_int_id, m->num_packs);
 207
 208         if (m->packs[pack_int_id])
 209                 return 0;
 210
 211         strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
 212                     m->pack_names[pack_int_id]);
 213
 214         m->packs[pack_int_id] = add_packed_git(pack_name.buf, pack_name.len, m->local);
 215         strbuf_release(&pack_name);
 216         return !m->packs[pack_int_id];
 217 }
 218
 219 int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
 220 {
 221         return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
 222                             MIDX_HASH_LEN, result);
 223 }
 224
 225 struct object_id *nth_midxed_object_oid(struct object_id *oid,
 226                                         struct multi_pack_index *m,
 227                                         uint32_t n)
 228 {
 229         if (n >= m->num_objects)
 230                 return NULL;
 231
 232         hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
 233         return oid;
 234 }
 235
 236 static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
 237 {
 238         const unsigned char *offset_data;
 239         uint32_t offset32;
 240
 241         offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH;
 242         offset32 = get_be32(offset_data + sizeof(uint32_t));
 243
 244         if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
 245                 if (sizeof(off_t) < sizeof(uint64_t))
 246                         die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
 247
 248                 offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
 249                 return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
 250         }
 251
 252         return offset32;
 253 }
 254
 255 static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
 256 {
 257         return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH);
 258 }
 259
 260 static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *e, uint32_t pos)
 261 {
 262         uint32_t pack_int_id;
 263         struct packed_git *p;
 264
 265         if (pos >= m->num_objects)
 266                 return 0;
 267
 268         pack_int_id = nth_midxed_pack_int_id(m, pos);
 269
 270         if (prepare_midx_pack(m, pack_int_id))
 271                 die(_("error preparing packfile from multi-pack-index"));
 272         p = m->packs[pack_int_id];
 273
 274         /*
 275         * We are about to tell the caller where they can locate the
 276         * requested object.  We better make sure the packfile is
 277         * still here and can be accessed before supplying that
 278         * answer, as it may have been deleted since the MIDX was
 279         * loaded!
 280         */
 281         if (!is_pack_valid(p))
 282                 return 0;
 283
 284         if (p->num_bad_objects) {
 285                 uint32_t i;
 286                 struct object_id oid;
 287                 nth_midxed_object_oid(&oid, m, pos);
 288                 for (i = 0; i < p->num_bad_objects; i++)
 289                         if (hasheq(oid.hash,
 290                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
 291                                 return 0;
 292         }
 293
 294         e->offset = nth_midxed_offset(m, pos);
 295         e->p = p;
 296
 297         return 1;
 298 }
 299
 300 int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m)
 301 {
 302         uint32_t pos;
 303
 304         if (!bsearch_midx(oid, m, &pos))
 305                 return 0;
 306
 307         return nth_midxed_pack_entry(m, e, pos);
 308 }
 309
 310 int midx_contains_pack(struct multi_pack_index *m, const char *idx_name)
 311 {
 312         uint32_t first = 0, last = m->num_packs;
 313
 314         while (first < last) {
 315                 uint32_t mid = first + (last - first) / 2;
 316                 const char *current;
 317                 int cmp;
 318
 319                 current = m->pack_names[mid];
 320                 cmp = strcmp(idx_name, current);
 321                 if (!cmp)
 322                         return 1;
 323                 if (cmp > 0) {
 324                         first = mid + 1;
 325                         continue;
 326                 }
 327                 last = mid;
 328         }
 329
 330         return 0;
 331 }
 332
 333 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local)
 334 {
 335         struct multi_pack_index *m;
 336         struct multi_pack_index *m_search;
 337         int config_value;
 338         static int env_value = -1;
 339
 340         if (env_value < 0)
 341                 env_value = git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0);
 342
 343         if (!env_value &&
 344             (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
 345             !config_value))
 346                 return 0;
 347
 348         for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
 349                 if (!strcmp(object_dir, m_search->object_dir))
 350                         return 1;
 351
 352         m = load_multi_pack_index(object_dir, local);
 353
 354         if (m) {
 355                 m->next = r->objects->multi_pack_index;
 356                 r->objects->multi_pack_index = m;
 357                 return 1;
 358         }
 359
 360         return 0;
 361 }
 362
 363 static size_t write_midx_header(struct hashfile *f,
 364                                 unsigned char num_chunks,
 365                                 uint32_t num_packs)
 366 {
 367         unsigned char byte_values[4];
 368
 369         hashwrite_be32(f, MIDX_SIGNATURE);
 370         byte_values[0] = MIDX_VERSION;
 371         byte_values[1] = MIDX_HASH_VERSION;
 372         byte_values[2] = num_chunks;
 373         byte_values[3] = 0; /* unused */
 374         hashwrite(f, byte_values, sizeof(byte_values));
 375         hashwrite_be32(f, num_packs);
 376
 377         return MIDX_HEADER_SIZE;
 378 }
 379
 380 struct pack_list {
 381         struct packed_git **list;
 382         char **names;
 383         uint32_t nr;
 384         uint32_t alloc_list;
 385         uint32_t alloc_names;
 386         size_t pack_name_concat_len;
 387         struct multi_pack_index *m;
 388 };
 389
 390 static void add_pack_to_midx(const char *full_path, size_t full_path_len,
 391                              const char *file_name, void *data)
 392 {
 393         struct pack_list *packs = (struct pack_list *)data;
 394
 395         if (ends_with(file_name, ".idx")) {
 396                 if (packs->m && midx_contains_pack(packs->m, file_name))
 397                         return;
 398
 399                 ALLOC_GROW(packs->list, packs->nr + 1, packs->alloc_list);
 400                 ALLOC_GROW(packs->names, packs->nr + 1, packs->alloc_names);
 401
 402                 packs->list[packs->nr] = add_packed_git(full_path,
 403                                                         full_path_len,
 404                                                         0);
 405
 406                 if (!packs->list[packs->nr]) {
 407                         warning(_("failed to add packfile '%s'"),
 408                                 full_path);
 409                         return;
 410                 }
 411
 412                 if (open_pack_index(packs->list[packs->nr])) {
 413                         warning(_("failed to open pack-index '%s'"),
 414                                 full_path);
 415                         close_pack(packs->list[packs->nr]);
 416                         FREE_AND_NULL(packs->list[packs->nr]);
 417                         return;
 418                 }
 419
 420                 packs->names[packs->nr] = xstrdup(file_name);
 421                 packs->pack_name_concat_len += strlen(file_name) + 1;
 422                 packs->nr++;
 423         }
 424 }
 425
 426 struct pack_pair {
 427         uint32_t pack_int_id;
 428         char *pack_name;
 429 };
 430
 431 static int pack_pair_compare(const void *_a, const void *_b)
 432 {
 433         struct pack_pair *a = (struct pack_pair *)_a;
 434         struct pack_pair *b = (struct pack_pair *)_b;
 435         return strcmp(a->pack_name, b->pack_name);
 436 }
 437
 438 static void sort_packs_by_name(char **pack_names, uint32_t nr_packs, uint32_t *perm)
 439 {
 440         uint32_t i;
 441         struct pack_pair *pairs;
 442
 443         ALLOC_ARRAY(pairs, nr_packs);
 444
 445         for (i = 0; i < nr_packs; i++) {
 446                 pairs[i].pack_int_id = i;
 447                 pairs[i].pack_name = pack_names[i];
 448         }
 449
 450         QSORT(pairs, nr_packs, pack_pair_compare);
 451
 452         for (i = 0; i < nr_packs; i++) {
 453                 pack_names[i] = pairs[i].pack_name;
 454                 perm[pairs[i].pack_int_id] = i;
 455         }
 456
 457         free(pairs);
 458 }
 459
 460 struct pack_midx_entry {
 461         struct object_id oid;
 462         uint32_t pack_int_id;
 463         time_t pack_mtime;
 464         uint64_t offset;
 465 };
 466
 467 static int midx_oid_compare(const void *_a, const void *_b)
 468 {
 469         const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
 470         const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
 471         int cmp = oidcmp(&a->oid, &b->oid);
 472
 473         if (cmp)
 474                 return cmp;
 475
 476         if (a->pack_mtime > b->pack_mtime)
 477                 return -1;
 478         else if (a->pack_mtime < b->pack_mtime)
 479                 return 1;
 480
 481         return a->pack_int_id - b->pack_int_id;
 482 }
 483
 484 static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
 485                                       uint32_t *pack_perm,
 486                                       struct pack_midx_entry *e,
 487                                       uint32_t pos)
 488 {
 489         if (pos >= m->num_objects)
 490                 return 1;
 491
 492         nth_midxed_object_oid(&e->oid, m, pos);
 493         e->pack_int_id = pack_perm[nth_midxed_pack_int_id(m, pos)];
 494         e->offset = nth_midxed_offset(m, pos);
 495
 496         /* consider objects in midx to be from "old" packs */
 497         e->pack_mtime = 0;
 498         return 0;
 499 }
 500
 501 static void fill_pack_entry(uint32_t pack_int_id,
 502                             struct packed_git *p,
 503                             uint32_t cur_object,
 504                             struct pack_midx_entry *entry)
 505 {
 506         if (!nth_packed_object_oid(&entry->oid, p, cur_object))
 507                 die(_("failed to locate object %d in packfile"), cur_object);
 508
 509         entry->pack_int_id = pack_int_id;
 510         entry->pack_mtime = p->mtime;
 511
 512         entry->offset = nth_packed_object_offset(p, cur_object);
 513 }
 514
 515 /*
 516  * It is possible to artificially get into a state where there are many
 517  * duplicate copies of objects. That can create high memory pressure if
 518  * we are to create a list of all objects before de-duplication. To reduce
 519  * this memory pressure without a significant performance drop, automatically
 520  * group objects by the first byte of their object id. Use the IDX fanout
 521  * tables to group the data, copy to a local array, then sort.
 522  *
 523  * Copy only the de-duplicated entries (selected by most-recent modified time
 524  * of a packfile containing the object).
 525  */
 526 static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
 527                                                   struct packed_git **p,
 528                                                   uint32_t *perm,
 529                                                   uint32_t nr_packs,
 530                                                   uint32_t *nr_objects)
 531 {
 532         uint32_t cur_fanout, cur_pack, cur_object;
 533         uint32_t alloc_fanout, alloc_objects, total_objects = 0;
 534         struct pack_midx_entry *entries_by_fanout = NULL;
 535         struct pack_midx_entry *deduplicated_entries = NULL;
 536         uint32_t start_pack = m ? m->num_packs : 0;
 537
 538         for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
 539                 total_objects += p[cur_pack]->num_objects;
 540
 541         /*
 542          * As we de-duplicate by fanout value, we expect the fanout
 543          * slices to be evenly distributed, with some noise. Hence,
 544          * allocate slightly more than one 256th.
 545          */
 546         alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
 547
 548         ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
 549         ALLOC_ARRAY(deduplicated_entries, alloc_objects);
 550         *nr_objects = 0;
 551
 552         for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
 553                 uint32_t nr_fanout = 0;
 554
 555                 if (m) {
 556                         uint32_t start = 0, end;
 557
 558                         if (cur_fanout)
 559                                 start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
 560                         end = ntohl(m->chunk_oid_fanout[cur_fanout]);
 561
 562                         for (cur_object = start; cur_object < end; cur_object++) {
 563                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 564                                 nth_midxed_pack_midx_entry(m, perm,
 565                                                            &entries_by_fanout[nr_fanout],
 566                                                            cur_object);
 567                                 nr_fanout++;
 568                         }
 569                 }
 570
 571                 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
 572                         uint32_t start = 0, end;
 573
 574                         if (cur_fanout)
 575                                 start = get_pack_fanout(p[cur_pack], cur_fanout - 1);
 576                         end = get_pack_fanout(p[cur_pack], cur_fanout);
 577
 578                         for (cur_object = start; cur_object < end; cur_object++) {
 579                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 580                                 fill_pack_entry(perm[cur_pack], p[cur_pack], cur_object, &entries_by_fanout[nr_fanout]);
 581                                 nr_fanout++;
 582                         }
 583                 }
 584
 585                 QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
 586
 587                 /*
 588                  * The batch is now sorted by OID and then mtime (descending).
 589                  * Take only the first duplicate.
 590                  */
 591                 for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
 592                         if (cur_object && oideq(&entries_by_fanout[cur_object - 1].oid,
 593                                                 &entries_by_fanout[cur_object].oid))
 594                                 continue;
 595
 596                         ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
 597                         memcpy(&deduplicated_entries[*nr_objects],
 598                                &entries_by_fanout[cur_object],
 599                                sizeof(struct pack_midx_entry));
 600                         (*nr_objects)++;
 601                 }
 602         }
 603
 604         free(entries_by_fanout);
 605         return deduplicated_entries;
 606 }
 607
 608 static size_t write_midx_pack_names(struct hashfile *f,
 609                                     char **pack_names,
 610                                     uint32_t num_packs)
 611 {
 612         uint32_t i;
 613         unsigned char padding[MIDX_CHUNK_ALIGNMENT];
 614         size_t written = 0;
 615
 616         for (i = 0; i < num_packs; i++) {
 617                 size_t writelen = strlen(pack_names[i]) + 1;
 618
 619                 if (i && strcmp(pack_names[i], pack_names[i - 1]) <= 0)
 620                         BUG("incorrect pack-file order: %s before %s",
 621                             pack_names[i - 1],
 622                             pack_names[i]);
 623
 624                 hashwrite(f, pack_names[i], writelen);
 625                 written += writelen;
 626         }
 627
 628         /* add padding to be aligned */
 629         i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
 630         if (i < MIDX_CHUNK_ALIGNMENT) {
 631                 memset(padding, 0, sizeof(padding));
 632                 hashwrite(f, padding, i);
 633                 written += i;
 634         }
 635
 636         return written;
 637 }
 638
 639 static size_t write_midx_oid_fanout(struct hashfile *f,
 640                                     struct pack_midx_entry *objects,
 641                                     uint32_t nr_objects)
 642 {
 643         struct pack_midx_entry *list = objects;
 644         struct pack_midx_entry *last = objects + nr_objects;
 645         uint32_t count = 0;
 646         uint32_t i;
 647
 648         /*
 649         * Write the first-level table (the list is sorted,
 650         * but we use a 256-entry lookup to be able to avoid
 651         * having to do eight extra binary search iterations).
 652         */
 653         for (i = 0; i < 256; i++) {
 654                 struct pack_midx_entry *next = list;
 655
 656                 while (next < last && next->oid.hash[0] == i) {
 657                         count++;
 658                         next++;
 659                 }
 660
 661                 hashwrite_be32(f, count);
 662                 list = next;
 663         }
 664
 665         return MIDX_CHUNK_FANOUT_SIZE;
 666 }
 667
 668 static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
 669                                     struct pack_midx_entry *objects,
 670                                     uint32_t nr_objects)
 671 {
 672         struct pack_midx_entry *list = objects;
 673         uint32_t i;
 674         size_t written = 0;
 675
 676         for (i = 0; i < nr_objects; i++) {
 677                 struct pack_midx_entry *obj = list++;
 678
 679                 if (i < nr_objects - 1) {
 680                         struct pack_midx_entry *next = list;
 681                         if (oidcmp(&obj->oid, &next->oid) >= 0)
 682                                 BUG("OIDs not in order: %s >= %s",
 683                                     oid_to_hex(&obj->oid),
 684                                     oid_to_hex(&next->oid));
 685                 }
 686
 687                 hashwrite(f, obj->oid.hash, (int)hash_len);
 688                 written += hash_len;
 689         }
 690
 691         return written;
 692 }
 693
 694 static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
 695                                         struct pack_midx_entry *objects, uint32_t nr_objects)
 696 {
 697         struct pack_midx_entry *list = objects;
 698         uint32_t i, nr_large_offset = 0;
 699         size_t written = 0;
 700
 701         for (i = 0; i < nr_objects; i++) {
 702                 struct pack_midx_entry *obj = list++;
 703
 704                 hashwrite_be32(f, obj->pack_int_id);
 705
 706                 if (large_offset_needed && obj->offset >> 31)
 707                         hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
 708                 else if (!large_offset_needed && obj->offset >> 32)
 709                         BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
 710                             oid_to_hex(&obj->oid),
 711                             obj->offset);
 712                 else
 713                         hashwrite_be32(f, (uint32_t)obj->offset);
 714
 715                 written += MIDX_CHUNK_OFFSET_WIDTH;
 716         }
 717
 718         return written;
 719 }
 720
 721 static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset,
 722                                        struct pack_midx_entry *objects, uint32_t nr_objects)
 723 {
 724         struct pack_midx_entry *list = objects, *end = objects + nr_objects;
 725         size_t written = 0;
 726
 727         while (nr_large_offset) {
 728                 struct pack_midx_entry *obj;
 729                 uint64_t offset;
 730
 731                 if (list >= end)
 732                         BUG("too many large-offset objects");
 733
 734                 obj = list++;
 735                 offset = obj->offset;
 736
 737                 if (!(offset >> 31))
 738                         continue;
 739
 740                 hashwrite_be32(f, offset >> 32);
 741                 hashwrite_be32(f, offset & 0xffffffffUL);
 742                 written += 2 * sizeof(uint32_t);
 743
 744                 nr_large_offset--;
 745         }
 746
 747         return written;
 748 }
 749
 750 int write_midx_file(const char *object_dir)
 751 {
 752         unsigned char cur_chunk, num_chunks = 0;
 753         char *midx_name;
 754         uint32_t i;
 755         struct hashfile *f = NULL;
 756         struct lock_file lk;
 757         struct pack_list packs;
 758         uint32_t *pack_perm = NULL;
 759         uint64_t written = 0;
 760         uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1];
 761         uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
 762         uint32_t nr_entries, num_large_offsets = 0;
 763         struct pack_midx_entry *entries = NULL;
 764         int large_offsets_needed = 0;
 765
 766         midx_name = get_midx_filename(object_dir);
 767         if (safe_create_leading_directories(midx_name)) {
 768                 UNLEAK(midx_name);
 769                 die_errno(_("unable to create leading directories of %s"),
 770                           midx_name);
 771         }
 772
 773         packs.m = load_multi_pack_index(object_dir, 1);
 774
 775         packs.nr = 0;
 776         packs.alloc_list = packs.m ? packs.m->num_packs : 16;
 777         packs.alloc_names = packs.alloc_list;
 778         packs.list = NULL;
 779         packs.names = NULL;
 780         packs.pack_name_concat_len = 0;
 781         ALLOC_ARRAY(packs.list, packs.alloc_list);
 782         ALLOC_ARRAY(packs.names, packs.alloc_names);
 783
 784         if (packs.m) {
 785                 for (i = 0; i < packs.m->num_packs; i++) {
 786                         ALLOC_GROW(packs.list, packs.nr + 1, packs.alloc_list);
 787                         ALLOC_GROW(packs.names, packs.nr + 1, packs.alloc_names);
 788
 789                         packs.list[packs.nr] = NULL;
 790                         packs.names[packs.nr] = xstrdup(packs.m->pack_names[i]);
 791                         packs.pack_name_concat_len += strlen(packs.names[packs.nr]) + 1;
 792                         packs.nr++;
 793                 }
 794         }
 795
 796         for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
 797
 798         if (packs.m && packs.nr == packs.m->num_packs)
 799                 goto cleanup;
 800
 801         if (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
 802                 packs.pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
 803                                               (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
 804
 805         ALLOC_ARRAY(pack_perm, packs.nr);
 806         sort_packs_by_name(packs.names, packs.nr, pack_perm);
 807
 808         entries = get_sorted_entries(packs.m, packs.list, pack_perm, packs.nr, &nr_entries);
 809
 810         for (i = 0; i < nr_entries; i++) {
 811                 if (entries[i].offset > 0x7fffffff)
 812                         num_large_offsets++;
 813                 if (entries[i].offset > 0xffffffff)
 814                         large_offsets_needed = 1;
 815         }
 816
 817         hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
 818         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
 819         FREE_AND_NULL(midx_name);
 820
 821         if (packs.m)
 822                 close_midx(packs.m);
 823
 824         cur_chunk = 0;
 825         num_chunks = large_offsets_needed ? 5 : 4;
 826
 827         written = write_midx_header(f, num_chunks, packs.nr);
 828
 829         chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES;
 830         chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
 831
 832         cur_chunk++;
 833         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT;
 834         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len;
 835
 836         cur_chunk++;
 837         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
 838         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE;
 839
 840         cur_chunk++;
 841         chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
 842         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN;
 843
 844         cur_chunk++;
 845         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
 846         if (large_offsets_needed) {
 847                 chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS;
 848
 849                 cur_chunk++;
 850                 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] +
 851                                            num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH;
 852         }
 853
 854         chunk_ids[cur_chunk] = 0;
 855
 856         for (i = 0; i <= num_chunks; i++) {
 857                 if (i && chunk_offsets[i] < chunk_offsets[i - 1])
 858                         BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
 859                             chunk_offsets[i - 1],
 860                             chunk_offsets[i]);
 861
 862                 if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT)
 863                         BUG("chunk offset %"PRIu64" is not properly aligned",
 864                             chunk_offsets[i]);
 865
 866                 hashwrite_be32(f, chunk_ids[i]);
 867                 hashwrite_be32(f, chunk_offsets[i] >> 32);
 868                 hashwrite_be32(f, chunk_offsets[i]);
 869
 870                 written += MIDX_CHUNKLOOKUP_WIDTH;
 871         }
 872
 873         for (i = 0; i < num_chunks; i++) {
 874                 if (written != chunk_offsets[i])
 875                         BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
 876                             chunk_offsets[i],
 877                             written,
 878                             chunk_ids[i]);
 879
 880                 switch (chunk_ids[i]) {
 881                         case MIDX_CHUNKID_PACKNAMES:
 882                                 written += write_midx_pack_names(f, packs.names, packs.nr);
 883                                 break;
 884
 885                         case MIDX_CHUNKID_OIDFANOUT:
 886                                 written += write_midx_oid_fanout(f, entries, nr_entries);
 887                                 break;
 888
 889                         case MIDX_CHUNKID_OIDLOOKUP:
 890                                 written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries);
 891                                 break;
 892
 893                         case MIDX_CHUNKID_OBJECTOFFSETS:
 894                                 written += write_midx_object_offsets(f, large_offsets_needed, entries, nr_entries);
 895                                 break;
 896
 897                         case MIDX_CHUNKID_LARGEOFFSETS:
 898                                 written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries);
 899                                 break;
 900
 901                         default:
 902                                 BUG("trying to write unknown chunk id %"PRIx32,
 903                                     chunk_ids[i]);
 904                 }
 905         }
 906
 907         if (written != chunk_offsets[num_chunks])
 908                 BUG("incorrect final offset %"PRIu64" != %"PRIu64,
 909                     written,
 910                     chunk_offsets[num_chunks]);
 911
 912         finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
 913         commit_lock_file(&lk);
 914
 915 cleanup:
 916         for (i = 0; i < packs.nr; i++) {
 917                 if (packs.list[i]) {
 918                         close_pack(packs.list[i]);
 919                         free(packs.list[i]);
 920                 }
 921                 free(packs.names[i]);
 922         }
 923
 924         free(packs.list);
 925         free(packs.names);
 926         free(entries);
 927         free(pack_perm);
 928         free(midx_name);
 929         return 0;
 930 }
 931
 932 void clear_midx_file(struct repository *r)
 933 {
 934         char *midx = get_midx_filename(r->objects->objectdir);
 935
 936         if (r->objects && r->objects->multi_pack_index) {
 937                 close_midx(r->objects->multi_pack_index);
 938                 r->objects->multi_pack_index = NULL;
 939         }
 940
 941         if (remove_path(midx)) {
 942                 UNLEAK(midx);
 943                 die(_("failed to clear multi-pack-index at %s"), midx);
 944         }
 945
 946         free(midx);
 947 }
 948
 949 static int verify_midx_error;
 950
 951 static void midx_report(const char *fmt, ...)
 952 {
 953         va_list ap;
 954         verify_midx_error = 1;
 955         va_start(ap, fmt);
 956         vfprintf(stderr, fmt, ap);
 957         fprintf(stderr, "\n");
 958         va_end(ap);
 959 }
 960
 961 int verify_midx_file(const char *object_dir)
 962 {
 963         uint32_t i;
 964         struct progress *progress;
 965         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
 966         verify_midx_error = 0;
 967
 968         if (!m)
 969                 return 0;
 970
 971         for (i = 0; i < m->num_packs; i++) {
 972                 if (prepare_midx_pack(m, i))
 973                         midx_report("failed to load pack in position %d", i);
 974         }
 975
 976         for (i = 0; i < 255; i++) {
 977                 uint32_t oid_fanout1 = ntohl(m->chunk_oid_fanout[i]);
 978                 uint32_t oid_fanout2 = ntohl(m->chunk_oid_fanout[i + 1]);
 979
 980                 if (oid_fanout1 > oid_fanout2)
 981                         midx_report(_("oid fanout out of order: fanout[%d] = %"PRIx32" > %"PRIx32" = fanout[%d]"),
 982                                     i, oid_fanout1, oid_fanout2, i + 1);
 983         }
 984
 985         for (i = 0; i < m->num_objects - 1; i++) {
 986                 struct object_id oid1, oid2;
 987
 988                 nth_midxed_object_oid(&oid1, m, i);
 989                 nth_midxed_object_oid(&oid2, m, i + 1);
 990
 991                 if (oidcmp(&oid1, &oid2) >= 0)
 992                         midx_report(_("oid lookup out of order: oid[%d] = %s >= %s = oid[%d]"),
 993                                     i, oid_to_hex(&oid1), oid_to_hex(&oid2), i + 1);
 994         }
 995
 996         progress = start_progress(_("Verifying object offsets"), m->num_objects);
 997         for (i = 0; i < m->num_objects; i++) {
 998                 struct object_id oid;
 999                 struct pack_entry e;
1000                 off_t m_offset, p_offset;
1001
1002                 nth_midxed_object_oid(&oid, m, i);
1003                 if (!fill_midx_entry(&oid, &e, m)) {
1004                         midx_report(_("failed to load pack entry for oid[%d] = %s"),
1005                                     i, oid_to_hex(&oid));
1006                         continue;
1007                 }
1008
1009                 if (open_pack_index(e.p)) {
1010                         midx_report(_("failed to load pack-index for packfile %s"),
1011                                     e.p->pack_name);
1012                         break;
1013                 }
1014
1015                 m_offset = e.offset;
1016                 p_offset = find_pack_entry_one(oid.hash, e.p);
1017
1018                 if (m_offset != p_offset)
1019                         midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
1020                                     i, oid_to_hex(&oid), m_offset, p_offset);
1021
1022                 display_progress(progress, i + 1);
1023         }
1024         stop_progress(&progress);
1025
1026         return verify_midx_error;
1027 }