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 #include "trace2.h"
  12
  13 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
  14 #define MIDX_VERSION 1
  15 #define MIDX_BYTE_FILE_VERSION 4
  16 #define MIDX_BYTE_HASH_VERSION 5
  17 #define MIDX_BYTE_NUM_CHUNKS 6
  18 #define MIDX_BYTE_NUM_PACKS 8
  19 #define MIDX_HASH_VERSION 1
  20 #define MIDX_HEADER_SIZE 12
  21 #define MIDX_HASH_LEN 20
  22 #define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN)
  23
  24 #define MIDX_MAX_CHUNKS 5
  25 #define MIDX_CHUNK_ALIGNMENT 4
  26 #define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
  27 #define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  28 #define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  29 #define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
  30 #define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
  31 #define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
  32 #define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
  33 #define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
  34 #define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
  35 #define MIDX_LARGE_OFFSET_NEEDED 0x80000000
  36
  37 static char *get_midx_filename(const char *object_dir)
  38 {
  39         return xstrfmt("%s/pack/multi-pack-index", object_dir);
  40 }
  41
  42 struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
  43 {
  44         struct multi_pack_index *m = NULL;
  45         int fd;
  46         struct stat st;
  47         size_t midx_size;
  48         void *midx_map = NULL;
  49         uint32_t hash_version;
  50         char *midx_name = get_midx_filename(object_dir);
  51         uint32_t i;
  52         const char *cur_pack_name;
  53
  54         fd = git_open(midx_name);
  55
  56         if (fd < 0)
  57                 goto cleanup_fail;
  58         if (fstat(fd, &st)) {
  59                 error_errno(_("failed to read %s"), midx_name);
  60                 goto cleanup_fail;
  61         }
  62
  63         midx_size = xsize_t(st.st_size);
  64
  65         if (midx_size < MIDX_MIN_SIZE) {
  66                 error(_("multi-pack-index file %s is too small"), midx_name);
  67                 goto cleanup_fail;
  68         }
  69
  70         FREE_AND_NULL(midx_name);
  71
  72         midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
  73
  74         FLEX_ALLOC_MEM(m, object_dir, object_dir, strlen(object_dir));
  75         m->fd = fd;
  76         m->data = midx_map;
  77         m->data_len = midx_size;
  78         m->local = local;
  79
  80         m->signature = get_be32(m->data);
  81         if (m->signature != MIDX_SIGNATURE)
  82                 die(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
  83                       m->signature, MIDX_SIGNATURE);
  84
  85         m->version = m->data[MIDX_BYTE_FILE_VERSION];
  86         if (m->version != MIDX_VERSION)
  87                 die(_("multi-pack-index version %d not recognized"),
  88                       m->version);
  89
  90         hash_version = m->data[MIDX_BYTE_HASH_VERSION];
  91         if (hash_version != MIDX_HASH_VERSION)
  92                 die(_("hash version %u does not match"), hash_version);
  93         m->hash_len = MIDX_HASH_LEN;
  94
  95         m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
  96
  97         m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
  98
  99         for (i = 0; i < m->num_chunks; i++) {
 100                 uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
 101                                              MIDX_CHUNKLOOKUP_WIDTH * i);
 102                 uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
 103                                                  MIDX_CHUNKLOOKUP_WIDTH * i);
 104
 105                 if (chunk_offset >= m->data_len)
 106                         die(_("invalid chunk offset (too large)"));
 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                         die(_("multi-pack-index pack names out of order: '%s' before '%s'"),
 164                               m->pack_names[i - 1],
 165                               m->pack_names[i]);
 166         }
 167
 168         trace2_data_intmax("midx", the_repository, "load/num_packs", m->num_packs);
 169         trace2_data_intmax("midx", the_repository, "load/num_objects", m->num_objects);
 170
 171         return m;
 172
 173 cleanup_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
 183 void 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
 204 int 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                 die(_("bad pack-int-id: %u (%u total packs)"),
 210                     pack_int_id, m->num_packs);
 211
 212         if (m->packs[pack_int_id])
 213                 return 0;
 214
 215         strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
 216                     m->pack_names[pack_int_id]);
 217
 218         m->packs[pack_int_id] = add_packed_git(pack_name.buf, pack_name.len, m->local);
 219         strbuf_release(&pack_name);
 220         return !m->packs[pack_int_id];
 221 }
 222
 223 int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
 224 {
 225         return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
 226                             MIDX_HASH_LEN, result);
 227 }
 228
 229 struct object_id *nth_midxed_object_oid(struct object_id *oid,
 230                                         struct multi_pack_index *m,
 231                                         uint32_t n)
 232 {
 233         if (n >= m->num_objects)
 234                 return NULL;
 235
 236         hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
 237         return oid;
 238 }
 239
 240 static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
 241 {
 242         const unsigned char *offset_data;
 243         uint32_t offset32;
 244
 245         offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH;
 246         offset32 = get_be32(offset_data + sizeof(uint32_t));
 247
 248         if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
 249                 if (sizeof(off_t) < sizeof(uint64_t))
 250                         die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
 251
 252                 offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
 253                 return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
 254         }
 255
 256         return offset32;
 257 }
 258
 259 static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
 260 {
 261         return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH);
 262 }
 263
 264 static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *e, uint32_t pos)
 265 {
 266         uint32_t pack_int_id;
 267         struct packed_git *p;
 268
 269         if (pos >= m->num_objects)
 270                 return 0;
 271
 272         pack_int_id = nth_midxed_pack_int_id(m, pos);
 273
 274         if (prepare_midx_pack(m, pack_int_id))
 275                 die(_("error preparing packfile from multi-pack-index"));
 276         p = m->packs[pack_int_id];
 277
 278         /*
 279         * We are about to tell the caller where they can locate the
 280         * requested object.  We better make sure the packfile is
 281         * still here and can be accessed before supplying that
 282         * answer, as it may have been deleted since the MIDX was
 283         * loaded!
 284         */
 285         if (!is_pack_valid(p))
 286                 return 0;
 287
 288         if (p->num_bad_objects) {
 289                 uint32_t i;
 290                 struct object_id oid;
 291                 nth_midxed_object_oid(&oid, m, pos);
 292                 for (i = 0; i < p->num_bad_objects; i++)
 293                         if (hasheq(oid.hash,
 294                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
 295                                 return 0;
 296         }
 297
 298         e->offset = nth_midxed_offset(m, pos);
 299         e->p = p;
 300
 301         return 1;
 302 }
 303
 304 int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m)
 305 {
 306         uint32_t pos;
 307
 308         if (!bsearch_midx(oid, m, &pos))
 309                 return 0;
 310
 311         return nth_midxed_pack_entry(m, e, pos);
 312 }
 313
 314 int midx_contains_pack(struct multi_pack_index *m, const char *idx_name)
 315 {
 316         uint32_t first = 0, last = m->num_packs;
 317
 318         while (first < last) {
 319                 uint32_t mid = first + (last - first) / 2;
 320                 const char *current;
 321                 int cmp;
 322
 323                 current = m->pack_names[mid];
 324                 cmp = strcmp(idx_name, current);
 325                 if (!cmp)
 326                         return 1;
 327                 if (cmp > 0) {
 328                         first = mid + 1;
 329                         continue;
 330                 }
 331                 last = mid;
 332         }
 333
 334         return 0;
 335 }
 336
 337 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local)
 338 {
 339         struct multi_pack_index *m;
 340         struct multi_pack_index *m_search;
 341         int config_value;
 342         static int env_value = -1;
 343
 344         if (env_value < 0)
 345                 env_value = git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0);
 346
 347         if (!env_value &&
 348             (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
 349             !config_value))
 350                 return 0;
 351
 352         for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
 353                 if (!strcmp(object_dir, m_search->object_dir))
 354                         return 1;
 355
 356         m = load_multi_pack_index(object_dir, local);
 357
 358         if (m) {
 359                 m->next = r->objects->multi_pack_index;
 360                 r->objects->multi_pack_index = m;
 361                 return 1;
 362         }
 363
 364         return 0;
 365 }
 366
 367 static size_t write_midx_header(struct hashfile *f,
 368                                 unsigned char num_chunks,
 369                                 uint32_t num_packs)
 370 {
 371         unsigned char byte_values[4];
 372
 373         hashwrite_be32(f, MIDX_SIGNATURE);
 374         byte_values[0] = MIDX_VERSION;
 375         byte_values[1] = MIDX_HASH_VERSION;
 376         byte_values[2] = num_chunks;
 377         byte_values[3] = 0; /* unused */
 378         hashwrite(f, byte_values, sizeof(byte_values));
 379         hashwrite_be32(f, num_packs);
 380
 381         return MIDX_HEADER_SIZE;
 382 }
 383
 384 struct pack_list {
 385         struct packed_git **list;
 386         char **names;
 387         uint32_t nr;
 388         uint32_t alloc_list;
 389         uint32_t alloc_names;
 390         size_t pack_name_concat_len;
 391         struct multi_pack_index *m;
 392 };
 393
 394 static void add_pack_to_midx(const char *full_path, size_t full_path_len,
 395                              const char *file_name, void *data)
 396 {
 397         struct pack_list *packs = (struct pack_list *)data;
 398
 399         if (ends_with(file_name, ".idx")) {
 400                 if (packs->m && midx_contains_pack(packs->m, file_name))
 401                         return;
 402
 403                 ALLOC_GROW(packs->list, packs->nr + 1, packs->alloc_list);
 404                 ALLOC_GROW(packs->names, packs->nr + 1, packs->alloc_names);
 405
 406                 packs->list[packs->nr] = add_packed_git(full_path,
 407                                                         full_path_len,
 408                                                         0);
 409
 410                 if (!packs->list[packs->nr]) {
 411                         warning(_("failed to add packfile '%s'"),
 412                                 full_path);
 413                         return;
 414                 }
 415
 416                 if (open_pack_index(packs->list[packs->nr])) {
 417                         warning(_("failed to open pack-index '%s'"),
 418                                 full_path);
 419                         close_pack(packs->list[packs->nr]);
 420                         FREE_AND_NULL(packs->list[packs->nr]);
 421                         return;
 422                 }
 423
 424                 packs->names[packs->nr] = xstrdup(file_name);
 425                 packs->pack_name_concat_len += strlen(file_name) + 1;
 426                 packs->nr++;
 427         }
 428 }
 429
 430 struct pack_pair {
 431         uint32_t pack_int_id;
 432         char *pack_name;
 433 };
 434
 435 static int pack_pair_compare(const void *_a, const void *_b)
 436 {
 437         struct pack_pair *a = (struct pack_pair *)_a;
 438         struct pack_pair *b = (struct pack_pair *)_b;
 439         return strcmp(a->pack_name, b->pack_name);
 440 }
 441
 442 static void sort_packs_by_name(char **pack_names, uint32_t nr_packs, uint32_t *perm)
 443 {
 444         uint32_t i;
 445         struct pack_pair *pairs;
 446
 447         ALLOC_ARRAY(pairs, nr_packs);
 448
 449         for (i = 0; i < nr_packs; i++) {
 450                 pairs[i].pack_int_id = i;
 451                 pairs[i].pack_name = pack_names[i];
 452         }
 453
 454         QSORT(pairs, nr_packs, pack_pair_compare);
 455
 456         for (i = 0; i < nr_packs; i++) {
 457                 pack_names[i] = pairs[i].pack_name;
 458                 perm[pairs[i].pack_int_id] = i;
 459         }
 460
 461         free(pairs);
 462 }
 463
 464 struct pack_midx_entry {
 465         struct object_id oid;
 466         uint32_t pack_int_id;
 467         time_t pack_mtime;
 468         uint64_t offset;
 469 };
 470
 471 static int midx_oid_compare(const void *_a, const void *_b)
 472 {
 473         const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
 474         const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
 475         int cmp = oidcmp(&a->oid, &b->oid);
 476
 477         if (cmp)
 478                 return cmp;
 479
 480         if (a->pack_mtime > b->pack_mtime)
 481                 return -1;
 482         else if (a->pack_mtime < b->pack_mtime)
 483                 return 1;
 484
 485         return a->pack_int_id - b->pack_int_id;
 486 }
 487
 488 static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
 489                                       uint32_t *pack_perm,
 490                                       struct pack_midx_entry *e,
 491                                       uint32_t pos)
 492 {
 493         if (pos >= m->num_objects)
 494                 return 1;
 495
 496         nth_midxed_object_oid(&e->oid, m, pos);
 497         e->pack_int_id = pack_perm[nth_midxed_pack_int_id(m, pos)];
 498         e->offset = nth_midxed_offset(m, pos);
 499
 500         /* consider objects in midx to be from "old" packs */
 501         e->pack_mtime = 0;
 502         return 0;
 503 }
 504
 505 static void fill_pack_entry(uint32_t pack_int_id,
 506                             struct packed_git *p,
 507                             uint32_t cur_object,
 508                             struct pack_midx_entry *entry)
 509 {
 510         if (!nth_packed_object_oid(&entry->oid, p, cur_object))
 511                 die(_("failed to locate object %d in packfile"), cur_object);
 512
 513         entry->pack_int_id = pack_int_id;
 514         entry->pack_mtime = p->mtime;
 515
 516         entry->offset = nth_packed_object_offset(p, cur_object);
 517 }
 518
 519 /*
 520  * It is possible to artificially get into a state where there are many
 521  * duplicate copies of objects. That can create high memory pressure if
 522  * we are to create a list of all objects before de-duplication. To reduce
 523  * this memory pressure without a significant performance drop, automatically
 524  * group objects by the first byte of their object id. Use the IDX fanout
 525  * tables to group the data, copy to a local array, then sort.
 526  *
 527  * Copy only the de-duplicated entries (selected by most-recent modified time
 528  * of a packfile containing the object).
 529  */
 530 static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
 531                                                   struct packed_git **p,
 532                                                   uint32_t *perm,
 533                                                   uint32_t nr_packs,
 534                                                   uint32_t *nr_objects)
 535 {
 536         uint32_t cur_fanout, cur_pack, cur_object;
 537         uint32_t alloc_fanout, alloc_objects, total_objects = 0;
 538         struct pack_midx_entry *entries_by_fanout = NULL;
 539         struct pack_midx_entry *deduplicated_entries = NULL;
 540         uint32_t start_pack = m ? m->num_packs : 0;
 541
 542         for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
 543                 total_objects += p[cur_pack]->num_objects;
 544
 545         /*
 546          * As we de-duplicate by fanout value, we expect the fanout
 547          * slices to be evenly distributed, with some noise. Hence,
 548          * allocate slightly more than one 256th.
 549          */
 550         alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
 551
 552         ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
 553         ALLOC_ARRAY(deduplicated_entries, alloc_objects);
 554         *nr_objects = 0;
 555
 556         for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
 557                 uint32_t nr_fanout = 0;
 558
 559                 if (m) {
 560                         uint32_t start = 0, end;
 561
 562                         if (cur_fanout)
 563                                 start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
 564                         end = ntohl(m->chunk_oid_fanout[cur_fanout]);
 565
 566                         for (cur_object = start; cur_object < end; cur_object++) {
 567                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 568                                 nth_midxed_pack_midx_entry(m, perm,
 569                                                            &entries_by_fanout[nr_fanout],
 570                                                            cur_object);
 571                                 nr_fanout++;
 572                         }
 573                 }
 574
 575                 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
 576                         uint32_t start = 0, end;
 577
 578                         if (cur_fanout)
 579                                 start = get_pack_fanout(p[cur_pack], cur_fanout - 1);
 580                         end = get_pack_fanout(p[cur_pack], cur_fanout);
 581
 582                         for (cur_object = start; cur_object < end; cur_object++) {
 583                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 584                                 fill_pack_entry(perm[cur_pack], p[cur_pack], cur_object, &entries_by_fanout[nr_fanout]);
 585                                 nr_fanout++;
 586                         }
 587                 }
 588
 589                 QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
 590
 591                 /*
 592                  * The batch is now sorted by OID and then mtime (descending).
 593                  * Take only the first duplicate.
 594                  */
 595                 for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
 596                         if (cur_object && oideq(&entries_by_fanout[cur_object - 1].oid,
 597                                                 &entries_by_fanout[cur_object].oid))
 598                                 continue;
 599
 600                         ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
 601                         memcpy(&deduplicated_entries[*nr_objects],
 602                                &entries_by_fanout[cur_object],
 603                                sizeof(struct pack_midx_entry));
 604                         (*nr_objects)++;
 605                 }
 606         }
 607
 608         free(entries_by_fanout);
 609         return deduplicated_entries;
 610 }
 611
 612 static size_t write_midx_pack_names(struct hashfile *f,
 613                                     char **pack_names,
 614                                     uint32_t num_packs)
 615 {
 616         uint32_t i;
 617         unsigned char padding[MIDX_CHUNK_ALIGNMENT];
 618         size_t written = 0;
 619
 620         for (i = 0; i < num_packs; i++) {
 621                 size_t writelen = strlen(pack_names[i]) + 1;
 622
 623                 if (i && strcmp(pack_names[i], pack_names[i - 1]) <= 0)
 624                         BUG("incorrect pack-file order: %s before %s",
 625                             pack_names[i - 1],
 626                             pack_names[i]);
 627
 628                 hashwrite(f, pack_names[i], writelen);
 629                 written += writelen;
 630         }
 631
 632         /* add padding to be aligned */
 633         i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
 634         if (i < MIDX_CHUNK_ALIGNMENT) {
 635                 memset(padding, 0, sizeof(padding));
 636                 hashwrite(f, padding, i);
 637                 written += i;
 638         }
 639
 640         return written;
 641 }
 642
 643 static size_t write_midx_oid_fanout(struct hashfile *f,
 644                                     struct pack_midx_entry *objects,
 645                                     uint32_t nr_objects)
 646 {
 647         struct pack_midx_entry *list = objects;
 648         struct pack_midx_entry *last = objects + nr_objects;
 649         uint32_t count = 0;
 650         uint32_t i;
 651
 652         /*
 653         * Write the first-level table (the list is sorted,
 654         * but we use a 256-entry lookup to be able to avoid
 655         * having to do eight extra binary search iterations).
 656         */
 657         for (i = 0; i < 256; i++) {
 658                 struct pack_midx_entry *next = list;
 659
 660                 while (next < last && next->oid.hash[0] == i) {
 661                         count++;
 662                         next++;
 663                 }
 664
 665                 hashwrite_be32(f, count);
 666                 list = next;
 667         }
 668
 669         return MIDX_CHUNK_FANOUT_SIZE;
 670 }
 671
 672 static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
 673                                     struct pack_midx_entry *objects,
 674                                     uint32_t nr_objects)
 675 {
 676         struct pack_midx_entry *list = objects;
 677         uint32_t i;
 678         size_t written = 0;
 679
 680         for (i = 0; i < nr_objects; i++) {
 681                 struct pack_midx_entry *obj = list++;
 682
 683                 if (i < nr_objects - 1) {
 684                         struct pack_midx_entry *next = list;
 685                         if (oidcmp(&obj->oid, &next->oid) >= 0)
 686                                 BUG("OIDs not in order: %s >= %s",
 687                                     oid_to_hex(&obj->oid),
 688                                     oid_to_hex(&next->oid));
 689                 }
 690
 691                 hashwrite(f, obj->oid.hash, (int)hash_len);
 692                 written += hash_len;
 693         }
 694
 695         return written;
 696 }
 697
 698 static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
 699                                         struct pack_midx_entry *objects, uint32_t nr_objects)
 700 {
 701         struct pack_midx_entry *list = objects;
 702         uint32_t i, nr_large_offset = 0;
 703         size_t written = 0;
 704
 705         for (i = 0; i < nr_objects; i++) {
 706                 struct pack_midx_entry *obj = list++;
 707
 708                 hashwrite_be32(f, obj->pack_int_id);
 709
 710                 if (large_offset_needed && obj->offset >> 31)
 711                         hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
 712                 else if (!large_offset_needed && obj->offset >> 32)
 713                         BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
 714                             oid_to_hex(&obj->oid),
 715                             obj->offset);
 716                 else
 717                         hashwrite_be32(f, (uint32_t)obj->offset);
 718
 719                 written += MIDX_CHUNK_OFFSET_WIDTH;
 720         }
 721
 722         return written;
 723 }
 724
 725 static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset,
 726                                        struct pack_midx_entry *objects, uint32_t nr_objects)
 727 {
 728         struct pack_midx_entry *list = objects, *end = objects + nr_objects;
 729         size_t written = 0;
 730
 731         while (nr_large_offset) {
 732                 struct pack_midx_entry *obj;
 733                 uint64_t offset;
 734
 735                 if (list >= end)
 736                         BUG("too many large-offset objects");
 737
 738                 obj = list++;
 739                 offset = obj->offset;
 740
 741                 if (!(offset >> 31))
 742                         continue;
 743
 744                 hashwrite_be32(f, offset >> 32);
 745                 hashwrite_be32(f, offset & 0xffffffffUL);
 746                 written += 2 * sizeof(uint32_t);
 747
 748                 nr_large_offset--;
 749         }
 750
 751         return written;
 752 }
 753
 754 int write_midx_file(const char *object_dir)
 755 {
 756         unsigned char cur_chunk, num_chunks = 0;
 757         char *midx_name;
 758         uint32_t i;
 759         struct hashfile *f = NULL;
 760         struct lock_file lk;
 761         struct pack_list packs;
 762         uint32_t *pack_perm = NULL;
 763         uint64_t written = 0;
 764         uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1];
 765         uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
 766         uint32_t nr_entries, num_large_offsets = 0;
 767         struct pack_midx_entry *entries = NULL;
 768         int large_offsets_needed = 0;
 769
 770         midx_name = get_midx_filename(object_dir);
 771         if (safe_create_leading_directories(midx_name)) {
 772                 UNLEAK(midx_name);
 773                 die_errno(_("unable to create leading directories of %s"),
 774                           midx_name);
 775         }
 776
 777         packs.m = load_multi_pack_index(object_dir, 1);
 778
 779         packs.nr = 0;
 780         packs.alloc_list = packs.m ? packs.m->num_packs : 16;
 781         packs.alloc_names = packs.alloc_list;
 782         packs.list = NULL;
 783         packs.names = NULL;
 784         packs.pack_name_concat_len = 0;
 785         ALLOC_ARRAY(packs.list, packs.alloc_list);
 786         ALLOC_ARRAY(packs.names, packs.alloc_names);
 787
 788         if (packs.m) {
 789                 for (i = 0; i < packs.m->num_packs; i++) {
 790                         ALLOC_GROW(packs.list, packs.nr + 1, packs.alloc_list);
 791                         ALLOC_GROW(packs.names, packs.nr + 1, packs.alloc_names);
 792
 793                         packs.list[packs.nr] = NULL;
 794                         packs.names[packs.nr] = xstrdup(packs.m->pack_names[i]);
 795                         packs.pack_name_concat_len += strlen(packs.names[packs.nr]) + 1;
 796                         packs.nr++;
 797                 }
 798         }
 799
 800         for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
 801
 802         if (packs.m && packs.nr == packs.m->num_packs)
 803                 goto cleanup;
 804
 805         if (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
 806                 packs.pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
 807                                               (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
 808
 809         ALLOC_ARRAY(pack_perm, packs.nr);
 810         sort_packs_by_name(packs.names, packs.nr, pack_perm);
 811
 812         entries = get_sorted_entries(packs.m, packs.list, pack_perm, packs.nr, &nr_entries);
 813
 814         for (i = 0; i < nr_entries; i++) {
 815                 if (entries[i].offset > 0x7fffffff)
 816                         num_large_offsets++;
 817                 if (entries[i].offset > 0xffffffff)
 818                         large_offsets_needed = 1;
 819         }
 820
 821         hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
 822         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
 823         FREE_AND_NULL(midx_name);
 824
 825         if (packs.m)
 826                 close_midx(packs.m);
 827
 828         cur_chunk = 0;
 829         num_chunks = large_offsets_needed ? 5 : 4;
 830
 831         written = write_midx_header(f, num_chunks, packs.nr);
 832
 833         chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES;
 834         chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
 835
 836         cur_chunk++;
 837         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT;
 838         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len;
 839
 840         cur_chunk++;
 841         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
 842         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE;
 843
 844         cur_chunk++;
 845         chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
 846         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN;
 847
 848         cur_chunk++;
 849         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
 850         if (large_offsets_needed) {
 851                 chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS;
 852
 853                 cur_chunk++;
 854                 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] +
 855                                            num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH;
 856         }
 857
 858         chunk_ids[cur_chunk] = 0;
 859
 860         for (i = 0; i <= num_chunks; i++) {
 861                 if (i && chunk_offsets[i] < chunk_offsets[i - 1])
 862                         BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
 863                             chunk_offsets[i - 1],
 864                             chunk_offsets[i]);
 865
 866                 if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT)
 867                         BUG("chunk offset %"PRIu64" is not properly aligned",
 868                             chunk_offsets[i]);
 869
 870                 hashwrite_be32(f, chunk_ids[i]);
 871                 hashwrite_be32(f, chunk_offsets[i] >> 32);
 872                 hashwrite_be32(f, chunk_offsets[i]);
 873
 874                 written += MIDX_CHUNKLOOKUP_WIDTH;
 875         }
 876
 877         for (i = 0; i < num_chunks; i++) {
 878                 if (written != chunk_offsets[i])
 879                         BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
 880                             chunk_offsets[i],
 881                             written,
 882                             chunk_ids[i]);
 883
 884                 switch (chunk_ids[i]) {
 885                         case MIDX_CHUNKID_PACKNAMES:
 886                                 written += write_midx_pack_names(f, packs.names, packs.nr);
 887                                 break;
 888
 889                         case MIDX_CHUNKID_OIDFANOUT:
 890                                 written += write_midx_oid_fanout(f, entries, nr_entries);
 891                                 break;
 892
 893                         case MIDX_CHUNKID_OIDLOOKUP:
 894                                 written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries);
 895                                 break;
 896
 897                         case MIDX_CHUNKID_OBJECTOFFSETS:
 898                                 written += write_midx_object_offsets(f, large_offsets_needed, entries, nr_entries);
 899                                 break;
 900
 901                         case MIDX_CHUNKID_LARGEOFFSETS:
 902                                 written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries);
 903                                 break;
 904
 905                         default:
 906                                 BUG("trying to write unknown chunk id %"PRIx32,
 907                                     chunk_ids[i]);
 908                 }
 909         }
 910
 911         if (written != chunk_offsets[num_chunks])
 912                 BUG("incorrect final offset %"PRIu64" != %"PRIu64,
 913                     written,
 914                     chunk_offsets[num_chunks]);
 915
 916         finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
 917         commit_lock_file(&lk);
 918
 919 cleanup:
 920         for (i = 0; i < packs.nr; i++) {
 921                 if (packs.list[i]) {
 922                         close_pack(packs.list[i]);
 923                         free(packs.list[i]);
 924                 }
 925                 free(packs.names[i]);
 926         }
 927
 928         free(packs.list);
 929         free(packs.names);
 930         free(entries);
 931         free(pack_perm);
 932         free(midx_name);
 933         return 0;
 934 }
 935
 936 void clear_midx_file(struct repository *r)
 937 {
 938         char *midx = get_midx_filename(r->objects->odb->path);
 939
 940         if (r->objects && r->objects->multi_pack_index) {
 941                 close_midx(r->objects->multi_pack_index);
 942                 r->objects->multi_pack_index = NULL;
 943         }
 944
 945         if (remove_path(midx)) {
 946                 UNLEAK(midx);
 947                 die(_("failed to clear multi-pack-index at %s"), midx);
 948         }
 949
 950         free(midx);
 951 }
 952
 953 static int verify_midx_error;
 954
 955 static void midx_report(const char *fmt, ...)
 956 {
 957         va_list ap;
 958         verify_midx_error = 1;
 959         va_start(ap, fmt);
 960         vfprintf(stderr, fmt, ap);
 961         fprintf(stderr, "\n");
 962         va_end(ap);
 963 }
 964
 965 struct pair_pos_vs_id
 966 {
 967         uint32_t pos;
 968         uint32_t pack_int_id;
 969 };
 970
 971 static int compare_pair_pos_vs_id(const void *_a, const void *_b)
 972 {
 973         struct pair_pos_vs_id *a = (struct pair_pos_vs_id *)_a;
 974         struct pair_pos_vs_id *b = (struct pair_pos_vs_id *)_b;
 975
 976         return b->pack_int_id - a->pack_int_id;
 977 }
 978
 979 /*
 980  * Limit calls to display_progress() for performance reasons.
 981  * The interval here was arbitrarily chosen.
 982  */
 983 #define SPARSE_PROGRESS_INTERVAL (1 << 12)
 984 #define midx_display_sparse_progress(progress, n) \
 985         do { \
 986                 uint64_t _n = (n); \
 987                 if ((_n & (SPARSE_PROGRESS_INTERVAL - 1)) == 0) \
 988                         display_progress(progress, _n); \
 989         } while (0)
 990
 991 int verify_midx_file(const char *object_dir)
 992 {
 993         struct pair_pos_vs_id *pairs = NULL;
 994         uint32_t i;
 995         struct progress *progress;
 996         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
 997         verify_midx_error = 0;
 998
 999         if (!m)
1000                 return 0;
1001
1002         progress = start_progress(_("Looking for referenced packfiles"),
1003                                   m->num_packs);
1004         for (i = 0; i < m->num_packs; i++) {
1005                 if (prepare_midx_pack(m, i))
1006                         midx_report("failed to load pack in position %d", i);
1007
1008                 display_progress(progress, i + 1);
1009         }
1010         stop_progress(&progress);
1011
1012         for (i = 0; i < 255; i++) {
1013                 uint32_t oid_fanout1 = ntohl(m->chunk_oid_fanout[i]);
1014                 uint32_t oid_fanout2 = ntohl(m->chunk_oid_fanout[i + 1]);
1015
1016                 if (oid_fanout1 > oid_fanout2)
1017                         midx_report(_("oid fanout out of order: fanout[%d] = %"PRIx32" > %"PRIx32" = fanout[%d]"),
1018                                     i, oid_fanout1, oid_fanout2, i + 1);
1019         }
1020
1021         progress = start_sparse_progress(_("Verifying OID order in MIDX"),
1022                                          m->num_objects - 1);
1023         for (i = 0; i < m->num_objects - 1; i++) {
1024                 struct object_id oid1, oid2;
1025
1026                 nth_midxed_object_oid(&oid1, m, i);
1027                 nth_midxed_object_oid(&oid2, m, i + 1);
1028
1029                 if (oidcmp(&oid1, &oid2) >= 0)
1030                         midx_report(_("oid lookup out of order: oid[%d] = %s >= %s = oid[%d]"),
1031                                     i, oid_to_hex(&oid1), oid_to_hex(&oid2), i + 1);
1032
1033                 midx_display_sparse_progress(progress, i + 1);
1034         }
1035         stop_progress(&progress);
1036
1037         /*
1038          * Create an array mapping each object to its packfile id.  Sort it
1039          * to group the objects by packfile.  Use this permutation to visit
1040          * each of the objects and only require 1 packfile to be open at a
1041          * time.
1042          */
1043         ALLOC_ARRAY(pairs, m->num_objects);
1044         for (i = 0; i < m->num_objects; i++) {
1045                 pairs[i].pos = i;
1046                 pairs[i].pack_int_id = nth_midxed_pack_int_id(m, i);
1047         }
1048
1049         progress = start_sparse_progress(_("Sorting objects by packfile"),
1050                                          m->num_objects);
1051         display_progress(progress, 0); /* TODO: Measure QSORT() progress */
1052         QSORT(pairs, m->num_objects, compare_pair_pos_vs_id);
1053         stop_progress(&progress);
1054
1055         progress = start_sparse_progress(_("Verifying object offsets"), m->num_objects);
1056         for (i = 0; i < m->num_objects; i++) {
1057                 struct object_id oid;
1058                 struct pack_entry e;
1059                 off_t m_offset, p_offset;
1060
1061                 if (i > 0 && pairs[i-1].pack_int_id != pairs[i].pack_int_id &&
1062                     m->packs[pairs[i-1].pack_int_id])
1063                 {
1064                         close_pack_fd(m->packs[pairs[i-1].pack_int_id]);
1065                         close_pack_index(m->packs[pairs[i-1].pack_int_id]);
1066                 }
1067
1068                 nth_midxed_object_oid(&oid, m, pairs[i].pos);
1069
1070                 if (!fill_midx_entry(&oid, &e, m)) {
1071                         midx_report(_("failed to load pack entry for oid[%d] = %s"),
1072                                     pairs[i].pos, oid_to_hex(&oid));
1073                         continue;
1074                 }
1075
1076                 if (open_pack_index(e.p)) {
1077                         midx_report(_("failed to load pack-index for packfile %s"),
1078                                     e.p->pack_name);
1079                         break;
1080                 }
1081
1082                 m_offset = e.offset;
1083                 p_offset = find_pack_entry_one(oid.hash, e.p);
1084
1085                 if (m_offset != p_offset)
1086                         midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
1087                                     pairs[i].pos, oid_to_hex(&oid), m_offset, p_offset);
1088
1089                 midx_display_sparse_progress(progress, i + 1);
1090         }
1091         stop_progress(&progress);
1092
1093         free(pairs);
1094
1095         return verify_midx_error;
1096 }