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 #include "run-command.h"
  13 #include "repository.h"
  14
  15 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
  16 #define MIDX_VERSION 1
  17 #define MIDX_BYTE_FILE_VERSION 4
  18 #define MIDX_BYTE_HASH_VERSION 5
  19 #define MIDX_BYTE_NUM_CHUNKS 6
  20 #define MIDX_BYTE_NUM_PACKS 8
  21 #define MIDX_HASH_VERSION 1
  22 #define MIDX_HEADER_SIZE 12
  23 #define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + the_hash_algo->rawsz)
  24
  25 #define MIDX_MAX_CHUNKS 5
  26 #define MIDX_CHUNK_ALIGNMENT 4
  27 #define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
  28 #define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  29 #define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  30 #define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
  31 #define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
  32 #define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
  33 #define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
  34 #define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
  35 #define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
  36 #define MIDX_LARGE_OFFSET_NEEDED 0x80000000
  37
  38 #define PACK_EXPIRED UINT_MAX
  39
  40 static char *get_midx_filename(const char *object_dir)
  41 {
  42         return xstrfmt("%s/pack/multi-pack-index", object_dir);
  43 }
  44
  45 struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
  46 {
  47         struct multi_pack_index *m = NULL;
  48         int fd;
  49         struct stat st;
  50         size_t midx_size;
  51         void *midx_map = NULL;
  52         uint32_t hash_version;
  53         char *midx_name = get_midx_filename(object_dir);
  54         uint32_t i;
  55         const char *cur_pack_name;
  56
  57         fd = git_open(midx_name);
  58
  59         if (fd < 0)
  60                 goto cleanup_fail;
  61         if (fstat(fd, &st)) {
  62                 error_errno(_("failed to read %s"), midx_name);
  63                 goto cleanup_fail;
  64         }
  65
  66         midx_size = xsize_t(st.st_size);
  67
  68         if (midx_size < MIDX_MIN_SIZE) {
  69                 error(_("multi-pack-index file %s is too small"), midx_name);
  70                 goto cleanup_fail;
  71         }
  72
  73         FREE_AND_NULL(midx_name);
  74
  75         midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
  76         close(fd);
  77
  78         FLEX_ALLOC_STR(m, object_dir, object_dir);
  79         m->data = midx_map;
  80         m->data_len = midx_size;
  81         m->local = local;
  82
  83         m->signature = get_be32(m->data);
  84         if (m->signature != MIDX_SIGNATURE)
  85                 die(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
  86                       m->signature, MIDX_SIGNATURE);
  87
  88         m->version = m->data[MIDX_BYTE_FILE_VERSION];
  89         if (m->version != MIDX_VERSION)
  90                 die(_("multi-pack-index version %d not recognized"),
  91                       m->version);
  92
  93         hash_version = m->data[MIDX_BYTE_HASH_VERSION];
  94         if (hash_version != MIDX_HASH_VERSION)
  95                 die(_("hash version %u does not match"), hash_version);
  96         m->hash_len = the_hash_algo->rawsz;
  97
  98         m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
  99
 100         m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
 101
 102         for (i = 0; i < m->num_chunks; i++) {
 103                 uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
 104                                              MIDX_CHUNKLOOKUP_WIDTH * i);
 105                 uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
 106                                                  MIDX_CHUNKLOOKUP_WIDTH * i);
 107
 108                 if (chunk_offset >= m->data_len)
 109                         die(_("invalid chunk offset (too large)"));
 110
 111                 switch (chunk_id) {
 112                         case MIDX_CHUNKID_PACKNAMES:
 113                                 m->chunk_pack_names = m->data + chunk_offset;
 114                                 break;
 115
 116                         case MIDX_CHUNKID_OIDFANOUT:
 117                                 m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset);
 118                                 break;
 119
 120                         case MIDX_CHUNKID_OIDLOOKUP:
 121                                 m->chunk_oid_lookup = m->data + chunk_offset;
 122                                 break;
 123
 124                         case MIDX_CHUNKID_OBJECTOFFSETS:
 125                                 m->chunk_object_offsets = m->data + chunk_offset;
 126                                 break;
 127
 128                         case MIDX_CHUNKID_LARGEOFFSETS:
 129                                 m->chunk_large_offsets = m->data + chunk_offset;
 130                                 break;
 131
 132                         case 0:
 133                                 die(_("terminating multi-pack-index chunk id appears earlier than expected"));
 134                                 break;
 135
 136                         default:
 137                                 /*
 138                                  * Do nothing on unrecognized chunks, allowing future
 139                                  * extensions to add optional chunks.
 140                                  */
 141                                 break;
 142                 }
 143         }
 144
 145         if (!m->chunk_pack_names)
 146                 die(_("multi-pack-index missing required pack-name chunk"));
 147         if (!m->chunk_oid_fanout)
 148                 die(_("multi-pack-index missing required OID fanout chunk"));
 149         if (!m->chunk_oid_lookup)
 150                 die(_("multi-pack-index missing required OID lookup chunk"));
 151         if (!m->chunk_object_offsets)
 152                 die(_("multi-pack-index missing required object offsets chunk"));
 153
 154         m->num_objects = ntohl(m->chunk_oid_fanout[255]);
 155
 156         m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
 157         m->packs = xcalloc(m->num_packs, sizeof(*m->packs));
 158
 159         cur_pack_name = (const char *)m->chunk_pack_names;
 160         for (i = 0; i < m->num_packs; i++) {
 161                 m->pack_names[i] = cur_pack_name;
 162
 163                 cur_pack_name += strlen(cur_pack_name) + 1;
 164
 165                 if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0)
 166                         die(_("multi-pack-index pack names out of order: '%s' before '%s'"),
 167                               m->pack_names[i - 1],
 168                               m->pack_names[i]);
 169         }
 170
 171         trace2_data_intmax("midx", the_repository, "load/num_packs", m->num_packs);
 172         trace2_data_intmax("midx", the_repository, "load/num_objects", m->num_objects);
 173
 174         return m;
 175
 176 cleanup_fail:
 177         free(m);
 178         free(midx_name);
 179         if (midx_map)
 180                 munmap(midx_map, midx_size);
 181         if (0 <= fd)
 182                 close(fd);
 183         return NULL;
 184 }
 185
 186 void close_midx(struct multi_pack_index *m)
 187 {
 188         uint32_t i;
 189
 190         if (!m)
 191                 return;
 192
 193         munmap((unsigned char *)m->data, m->data_len);
 194
 195         for (i = 0; i < m->num_packs; i++) {
 196                 if (m->packs[i])
 197                         m->packs[i]->multi_pack_index = 0;
 198         }
 199         FREE_AND_NULL(m->packs);
 200         FREE_AND_NULL(m->pack_names);
 201 }
 202
 203 int prepare_midx_pack(struct repository *r, struct multi_pack_index *m, uint32_t pack_int_id)
 204 {
 205         struct strbuf pack_name = STRBUF_INIT;
 206         struct packed_git *p;
 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         p = add_packed_git(pack_name.buf, pack_name.len, m->local);
 219         strbuf_release(&pack_name);
 220
 221         if (!p)
 222                 return 1;
 223
 224         p->multi_pack_index = 1;
 225         m->packs[pack_int_id] = p;
 226         install_packed_git(r, p);
 227         list_add_tail(&p->mru, &r->objects->packed_git_mru);
 228
 229         return 0;
 230 }
 231
 232 int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
 233 {
 234         return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
 235                             the_hash_algo->rawsz, result);
 236 }
 237
 238 struct object_id *nth_midxed_object_oid(struct object_id *oid,
 239                                         struct multi_pack_index *m,
 240                                         uint32_t n)
 241 {
 242         if (n >= m->num_objects)
 243                 return NULL;
 244
 245         hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
 246         return oid;
 247 }
 248
 249 static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
 250 {
 251         const unsigned char *offset_data;
 252         uint32_t offset32;
 253
 254         offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH;
 255         offset32 = get_be32(offset_data + sizeof(uint32_t));
 256
 257         if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
 258                 if (sizeof(off_t) < sizeof(uint64_t))
 259                         die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
 260
 261                 offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
 262                 return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
 263         }
 264
 265         return offset32;
 266 }
 267
 268 static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
 269 {
 270         return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH);
 271 }
 272
 273 static int nth_midxed_pack_entry(struct repository *r,
 274                                  struct multi_pack_index *m,
 275                                  struct pack_entry *e,
 276                                  uint32_t pos)
 277 {
 278         uint32_t pack_int_id;
 279         struct packed_git *p;
 280
 281         if (pos >= m->num_objects)
 282                 return 0;
 283
 284         pack_int_id = nth_midxed_pack_int_id(m, pos);
 285
 286         if (prepare_midx_pack(r, m, pack_int_id))
 287                 die(_("error preparing packfile from multi-pack-index"));
 288         p = m->packs[pack_int_id];
 289
 290         /*
 291         * We are about to tell the caller where they can locate the
 292         * requested object.  We better make sure the packfile is
 293         * still here and can be accessed before supplying that
 294         * answer, as it may have been deleted since the MIDX was
 295         * loaded!
 296         */
 297         if (!is_pack_valid(p))
 298                 return 0;
 299
 300         if (p->num_bad_objects) {
 301                 uint32_t i;
 302                 struct object_id oid;
 303                 nth_midxed_object_oid(&oid, m, pos);
 304                 for (i = 0; i < p->num_bad_objects; i++)
 305                         if (hasheq(oid.hash,
 306                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
 307                                 return 0;
 308         }
 309
 310         e->offset = nth_midxed_offset(m, pos);
 311         e->p = p;
 312
 313         return 1;
 314 }
 315
 316 int fill_midx_entry(struct repository * r,
 317                     const struct object_id *oid,
 318                     struct pack_entry *e,
 319                     struct multi_pack_index *m)
 320 {
 321         uint32_t pos;
 322
 323         if (!bsearch_midx(oid, m, &pos))
 324                 return 0;
 325
 326         return nth_midxed_pack_entry(r, m, e, pos);
 327 }
 328
 329 /* Match "foo.idx" against either "foo.pack" _or_ "foo.idx". */
 330 static int cmp_idx_or_pack_name(const char *idx_or_pack_name,
 331                                 const char *idx_name)
 332 {
 333         /* Skip past any initial matching prefix. */
 334         while (*idx_name && *idx_name == *idx_or_pack_name) {
 335                 idx_name++;
 336                 idx_or_pack_name++;
 337         }
 338
 339         /*
 340          * If we didn't match completely, we may have matched "pack-1234." and
 341          * be left with "idx" and "pack" respectively, which is also OK. We do
 342          * not have to check for "idx" and "idx", because that would have been
 343          * a complete match (and in that case these strcmps will be false, but
 344          * we'll correctly return 0 from the final strcmp() below.
 345          *
 346          * Technically this matches "fooidx" and "foopack", but we'd never have
 347          * such names in the first place.
 348          */
 349         if (!strcmp(idx_name, "idx") && !strcmp(idx_or_pack_name, "pack"))
 350                 return 0;
 351
 352         /*
 353          * This not only checks for a complete match, but also orders based on
 354          * the first non-identical character, which means our ordering will
 355          * match a raw strcmp(). That makes it OK to use this to binary search
 356          * a naively-sorted list.
 357          */
 358         return strcmp(idx_or_pack_name, idx_name);
 359 }
 360
 361 int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name)
 362 {
 363         uint32_t first = 0, last = m->num_packs;
 364
 365         while (first < last) {
 366                 uint32_t mid = first + (last - first) / 2;
 367                 const char *current;
 368                 int cmp;
 369
 370                 current = m->pack_names[mid];
 371                 cmp = cmp_idx_or_pack_name(idx_or_pack_name, current);
 372                 if (!cmp)
 373                         return 1;
 374                 if (cmp > 0) {
 375                         first = mid + 1;
 376                         continue;
 377                 }
 378                 last = mid;
 379         }
 380
 381         return 0;
 382 }
 383
 384 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local)
 385 {
 386         struct multi_pack_index *m;
 387         struct multi_pack_index *m_search;
 388
 389         prepare_repo_settings(r);
 390         if (!r->settings.core_multi_pack_index)
 391                 return 0;
 392
 393         for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
 394                 if (!strcmp(object_dir, m_search->object_dir))
 395                         return 1;
 396
 397         m = load_multi_pack_index(object_dir, local);
 398
 399         if (m) {
 400                 m->next = r->objects->multi_pack_index;
 401                 r->objects->multi_pack_index = m;
 402                 return 1;
 403         }
 404
 405         return 0;
 406 }
 407
 408 static size_t write_midx_header(struct hashfile *f,
 409                                 unsigned char num_chunks,
 410                                 uint32_t num_packs)
 411 {
 412         unsigned char byte_values[4];
 413
 414         hashwrite_be32(f, MIDX_SIGNATURE);
 415         byte_values[0] = MIDX_VERSION;
 416         byte_values[1] = MIDX_HASH_VERSION;
 417         byte_values[2] = num_chunks;
 418         byte_values[3] = 0; /* unused */
 419         hashwrite(f, byte_values, sizeof(byte_values));
 420         hashwrite_be32(f, num_packs);
 421
 422         return MIDX_HEADER_SIZE;
 423 }
 424
 425 struct pack_info {
 426         uint32_t orig_pack_int_id;
 427         char *pack_name;
 428         struct packed_git *p;
 429         unsigned expired : 1;
 430 };
 431
 432 static int pack_info_compare(const void *_a, const void *_b)
 433 {
 434         struct pack_info *a = (struct pack_info *)_a;
 435         struct pack_info *b = (struct pack_info *)_b;
 436         return strcmp(a->pack_name, b->pack_name);
 437 }
 438
 439 struct pack_list {
 440         struct pack_info *info;
 441         uint32_t nr;
 442         uint32_t alloc;
 443         struct multi_pack_index *m;
 444         struct progress *progress;
 445         unsigned pack_paths_checked;
 446 };
 447
 448 static void add_pack_to_midx(const char *full_path, size_t full_path_len,
 449                              const char *file_name, void *data)
 450 {
 451         struct pack_list *packs = (struct pack_list *)data;
 452
 453         if (ends_with(file_name, ".idx")) {
 454                 display_progress(packs->progress, ++packs->pack_paths_checked);
 455                 if (packs->m && midx_contains_pack(packs->m, file_name))
 456                         return;
 457
 458                 ALLOC_GROW(packs->info, packs->nr + 1, packs->alloc);
 459
 460                 packs->info[packs->nr].p = add_packed_git(full_path,
 461                                                           full_path_len,
 462                                                           0);
 463
 464                 if (!packs->info[packs->nr].p) {
 465                         warning(_("failed to add packfile '%s'"),
 466                                 full_path);
 467                         return;
 468                 }
 469
 470                 if (open_pack_index(packs->info[packs->nr].p)) {
 471                         warning(_("failed to open pack-index '%s'"),
 472                                 full_path);
 473                         close_pack(packs->info[packs->nr].p);
 474                         FREE_AND_NULL(packs->info[packs->nr].p);
 475                         return;
 476                 }
 477
 478                 packs->info[packs->nr].pack_name = xstrdup(file_name);
 479                 packs->info[packs->nr].orig_pack_int_id = packs->nr;
 480                 packs->info[packs->nr].expired = 0;
 481                 packs->nr++;
 482         }
 483 }
 484
 485 struct pack_midx_entry {
 486         struct object_id oid;
 487         uint32_t pack_int_id;
 488         time_t pack_mtime;
 489         uint64_t offset;
 490 };
 491
 492 static int midx_oid_compare(const void *_a, const void *_b)
 493 {
 494         const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
 495         const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
 496         int cmp = oidcmp(&a->oid, &b->oid);
 497
 498         if (cmp)
 499                 return cmp;
 500
 501         if (a->pack_mtime > b->pack_mtime)
 502                 return -1;
 503         else if (a->pack_mtime < b->pack_mtime)
 504                 return 1;
 505
 506         return a->pack_int_id - b->pack_int_id;
 507 }
 508
 509 static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
 510                                       struct pack_midx_entry *e,
 511                                       uint32_t pos)
 512 {
 513         if (pos >= m->num_objects)
 514                 return 1;
 515
 516         nth_midxed_object_oid(&e->oid, m, pos);
 517         e->pack_int_id = nth_midxed_pack_int_id(m, pos);
 518         e->offset = nth_midxed_offset(m, pos);
 519
 520         /* consider objects in midx to be from "old" packs */
 521         e->pack_mtime = 0;
 522         return 0;
 523 }
 524
 525 static void fill_pack_entry(uint32_t pack_int_id,
 526                             struct packed_git *p,
 527                             uint32_t cur_object,
 528                             struct pack_midx_entry *entry)
 529 {
 530         if (nth_packed_object_id(&entry->oid, p, cur_object) < 0)
 531                 die(_("failed to locate object %d in packfile"), cur_object);
 532
 533         entry->pack_int_id = pack_int_id;
 534         entry->pack_mtime = p->mtime;
 535
 536         entry->offset = nth_packed_object_offset(p, cur_object);
 537 }
 538
 539 /*
 540  * It is possible to artificially get into a state where there are many
 541  * duplicate copies of objects. That can create high memory pressure if
 542  * we are to create a list of all objects before de-duplication. To reduce
 543  * this memory pressure without a significant performance drop, automatically
 544  * group objects by the first byte of their object id. Use the IDX fanout
 545  * tables to group the data, copy to a local array, then sort.
 546  *
 547  * Copy only the de-duplicated entries (selected by most-recent modified time
 548  * of a packfile containing the object).
 549  */
 550 static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
 551                                                   struct pack_info *info,
 552                                                   uint32_t nr_packs,
 553                                                   uint32_t *nr_objects)
 554 {
 555         uint32_t cur_fanout, cur_pack, cur_object;
 556         uint32_t alloc_fanout, alloc_objects, total_objects = 0;
 557         struct pack_midx_entry *entries_by_fanout = NULL;
 558         struct pack_midx_entry *deduplicated_entries = NULL;
 559         uint32_t start_pack = m ? m->num_packs : 0;
 560
 561         for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
 562                 total_objects += info[cur_pack].p->num_objects;
 563
 564         /*
 565          * As we de-duplicate by fanout value, we expect the fanout
 566          * slices to be evenly distributed, with some noise. Hence,
 567          * allocate slightly more than one 256th.
 568          */
 569         alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
 570
 571         ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
 572         ALLOC_ARRAY(deduplicated_entries, alloc_objects);
 573         *nr_objects = 0;
 574
 575         for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
 576                 uint32_t nr_fanout = 0;
 577
 578                 if (m) {
 579                         uint32_t start = 0, end;
 580
 581                         if (cur_fanout)
 582                                 start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
 583                         end = ntohl(m->chunk_oid_fanout[cur_fanout]);
 584
 585                         for (cur_object = start; cur_object < end; cur_object++) {
 586                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 587                                 nth_midxed_pack_midx_entry(m,
 588                                                            &entries_by_fanout[nr_fanout],
 589                                                            cur_object);
 590                                 nr_fanout++;
 591                         }
 592                 }
 593
 594                 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
 595                         uint32_t start = 0, end;
 596
 597                         if (cur_fanout)
 598                                 start = get_pack_fanout(info[cur_pack].p, cur_fanout - 1);
 599                         end = get_pack_fanout(info[cur_pack].p, cur_fanout);
 600
 601                         for (cur_object = start; cur_object < end; cur_object++) {
 602                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 603                                 fill_pack_entry(cur_pack, info[cur_pack].p, cur_object, &entries_by_fanout[nr_fanout]);
 604                                 nr_fanout++;
 605                         }
 606                 }
 607
 608                 QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
 609
 610                 /*
 611                  * The batch is now sorted by OID and then mtime (descending).
 612                  * Take only the first duplicate.
 613                  */
 614                 for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
 615                         if (cur_object && oideq(&entries_by_fanout[cur_object - 1].oid,
 616                                                 &entries_by_fanout[cur_object].oid))
 617                                 continue;
 618
 619                         ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
 620                         memcpy(&deduplicated_entries[*nr_objects],
 621                                &entries_by_fanout[cur_object],
 622                                sizeof(struct pack_midx_entry));
 623                         (*nr_objects)++;
 624                 }
 625         }
 626
 627         free(entries_by_fanout);
 628         return deduplicated_entries;
 629 }
 630
 631 static size_t write_midx_pack_names(struct hashfile *f,
 632                                     struct pack_info *info,
 633                                     uint32_t num_packs)
 634 {
 635         uint32_t i;
 636         unsigned char padding[MIDX_CHUNK_ALIGNMENT];
 637         size_t written = 0;
 638
 639         for (i = 0; i < num_packs; i++) {
 640                 size_t writelen;
 641
 642                 if (info[i].expired)
 643                         continue;
 644
 645                 if (i && strcmp(info[i].pack_name, info[i - 1].pack_name) <= 0)
 646                         BUG("incorrect pack-file order: %s before %s",
 647                             info[i - 1].pack_name,
 648                             info[i].pack_name);
 649
 650                 writelen = strlen(info[i].pack_name) + 1;
 651                 hashwrite(f, info[i].pack_name, writelen);
 652                 written += writelen;
 653         }
 654
 655         /* add padding to be aligned */
 656         i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
 657         if (i < MIDX_CHUNK_ALIGNMENT) {
 658                 memset(padding, 0, sizeof(padding));
 659                 hashwrite(f, padding, i);
 660                 written += i;
 661         }
 662
 663         return written;
 664 }
 665
 666 static size_t write_midx_oid_fanout(struct hashfile *f,
 667                                     struct pack_midx_entry *objects,
 668                                     uint32_t nr_objects)
 669 {
 670         struct pack_midx_entry *list = objects;
 671         struct pack_midx_entry *last = objects + nr_objects;
 672         uint32_t count = 0;
 673         uint32_t i;
 674
 675         /*
 676         * Write the first-level table (the list is sorted,
 677         * but we use a 256-entry lookup to be able to avoid
 678         * having to do eight extra binary search iterations).
 679         */
 680         for (i = 0; i < 256; i++) {
 681                 struct pack_midx_entry *next = list;
 682
 683                 while (next < last && next->oid.hash[0] == i) {
 684                         count++;
 685                         next++;
 686                 }
 687
 688                 hashwrite_be32(f, count);
 689                 list = next;
 690         }
 691
 692         return MIDX_CHUNK_FANOUT_SIZE;
 693 }
 694
 695 static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
 696                                     struct pack_midx_entry *objects,
 697                                     uint32_t nr_objects)
 698 {
 699         struct pack_midx_entry *list = objects;
 700         uint32_t i;
 701         size_t written = 0;
 702
 703         for (i = 0; i < nr_objects; i++) {
 704                 struct pack_midx_entry *obj = list++;
 705
 706                 if (i < nr_objects - 1) {
 707                         struct pack_midx_entry *next = list;
 708                         if (oidcmp(&obj->oid, &next->oid) >= 0)
 709                                 BUG("OIDs not in order: %s >= %s",
 710                                     oid_to_hex(&obj->oid),
 711                                     oid_to_hex(&next->oid));
 712                 }
 713
 714                 hashwrite(f, obj->oid.hash, (int)hash_len);
 715                 written += hash_len;
 716         }
 717
 718         return written;
 719 }
 720
 721 static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
 722                                         uint32_t *perm,
 723                                         struct pack_midx_entry *objects, uint32_t nr_objects)
 724 {
 725         struct pack_midx_entry *list = objects;
 726         uint32_t i, nr_large_offset = 0;
 727         size_t written = 0;
 728
 729         for (i = 0; i < nr_objects; i++) {
 730                 struct pack_midx_entry *obj = list++;
 731
 732                 if (perm[obj->pack_int_id] == PACK_EXPIRED)
 733                         BUG("object %s is in an expired pack with int-id %d",
 734                             oid_to_hex(&obj->oid),
 735                             obj->pack_int_id);
 736
 737                 hashwrite_be32(f, perm[obj->pack_int_id]);
 738
 739                 if (large_offset_needed && obj->offset >> 31)
 740                         hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
 741                 else if (!large_offset_needed && obj->offset >> 32)
 742                         BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
 743                             oid_to_hex(&obj->oid),
 744                             obj->offset);
 745                 else
 746                         hashwrite_be32(f, (uint32_t)obj->offset);
 747
 748                 written += MIDX_CHUNK_OFFSET_WIDTH;
 749         }
 750
 751         return written;
 752 }
 753
 754 static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset,
 755                                        struct pack_midx_entry *objects, uint32_t nr_objects)
 756 {
 757         struct pack_midx_entry *list = objects, *end = objects + nr_objects;
 758         size_t written = 0;
 759
 760         while (nr_large_offset) {
 761                 struct pack_midx_entry *obj;
 762                 uint64_t offset;
 763
 764                 if (list >= end)
 765                         BUG("too many large-offset objects");
 766
 767                 obj = list++;
 768                 offset = obj->offset;
 769
 770                 if (!(offset >> 31))
 771                         continue;
 772
 773                 hashwrite_be32(f, offset >> 32);
 774                 hashwrite_be32(f, offset & 0xffffffffUL);
 775                 written += 2 * sizeof(uint32_t);
 776
 777                 nr_large_offset--;
 778         }
 779
 780         return written;
 781 }
 782
 783 static int write_midx_internal(const char *object_dir, struct multi_pack_index *m,
 784                                struct string_list *packs_to_drop, unsigned flags)
 785 {
 786         unsigned char cur_chunk, num_chunks = 0;
 787         char *midx_name;
 788         uint32_t i;
 789         struct hashfile *f = NULL;
 790         struct lock_file lk;
 791         struct pack_list packs;
 792         uint32_t *pack_perm = NULL;
 793         uint64_t written = 0;
 794         uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1];
 795         uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
 796         uint32_t nr_entries, num_large_offsets = 0;
 797         struct pack_midx_entry *entries = NULL;
 798         struct progress *progress = NULL;
 799         int large_offsets_needed = 0;
 800         int pack_name_concat_len = 0;
 801         int dropped_packs = 0;
 802         int result = 0;
 803
 804         midx_name = get_midx_filename(object_dir);
 805         if (safe_create_leading_directories(midx_name)) {
 806                 UNLEAK(midx_name);
 807                 die_errno(_("unable to create leading directories of %s"),
 808                           midx_name);
 809         }
 810
 811         if (m)
 812                 packs.m = m;
 813         else
 814                 packs.m = load_multi_pack_index(object_dir, 1);
 815
 816         packs.nr = 0;
 817         packs.alloc = packs.m ? packs.m->num_packs : 16;
 818         packs.info = NULL;
 819         ALLOC_ARRAY(packs.info, packs.alloc);
 820
 821         if (packs.m) {
 822                 for (i = 0; i < packs.m->num_packs; i++) {
 823                         ALLOC_GROW(packs.info, packs.nr + 1, packs.alloc);
 824
 825                         packs.info[packs.nr].orig_pack_int_id = i;
 826                         packs.info[packs.nr].pack_name = xstrdup(packs.m->pack_names[i]);
 827                         packs.info[packs.nr].p = NULL;
 828                         packs.info[packs.nr].expired = 0;
 829                         packs.nr++;
 830                 }
 831         }
 832
 833         packs.pack_paths_checked = 0;
 834         if (flags & MIDX_PROGRESS)
 835                 packs.progress = start_delayed_progress(_("Adding packfiles to multi-pack-index"), 0);
 836         else
 837                 packs.progress = NULL;
 838
 839         for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
 840         stop_progress(&packs.progress);
 841
 842         if (packs.m && packs.nr == packs.m->num_packs && !packs_to_drop)
 843                 goto cleanup;
 844
 845         entries = get_sorted_entries(packs.m, packs.info, packs.nr, &nr_entries);
 846
 847         for (i = 0; i < nr_entries; i++) {
 848                 if (entries[i].offset > 0x7fffffff)
 849                         num_large_offsets++;
 850                 if (entries[i].offset > 0xffffffff)
 851                         large_offsets_needed = 1;
 852         }
 853
 854         QSORT(packs.info, packs.nr, pack_info_compare);
 855
 856         if (packs_to_drop && packs_to_drop->nr) {
 857                 int drop_index = 0;
 858                 int missing_drops = 0;
 859
 860                 for (i = 0; i < packs.nr && drop_index < packs_to_drop->nr; i++) {
 861                         int cmp = strcmp(packs.info[i].pack_name,
 862                                          packs_to_drop->items[drop_index].string);
 863
 864                         if (!cmp) {
 865                                 drop_index++;
 866                                 packs.info[i].expired = 1;
 867                         } else if (cmp > 0) {
 868                                 error(_("did not see pack-file %s to drop"),
 869                                       packs_to_drop->items[drop_index].string);
 870                                 drop_index++;
 871                                 missing_drops++;
 872                                 i--;
 873                         } else {
 874                                 packs.info[i].expired = 0;
 875                         }
 876                 }
 877
 878                 if (missing_drops) {
 879                         result = 1;
 880                         goto cleanup;
 881                 }
 882         }
 883
 884         /*
 885          * pack_perm stores a permutation between pack-int-ids from the
 886          * previous multi-pack-index to the new one we are writing:
 887          *
 888          * pack_perm[old_id] = new_id
 889          */
 890         ALLOC_ARRAY(pack_perm, packs.nr);
 891         for (i = 0; i < packs.nr; i++) {
 892                 if (packs.info[i].expired) {
 893                         dropped_packs++;
 894                         pack_perm[packs.info[i].orig_pack_int_id] = PACK_EXPIRED;
 895                 } else {
 896                         pack_perm[packs.info[i].orig_pack_int_id] = i - dropped_packs;
 897                 }
 898         }
 899
 900         for (i = 0; i < packs.nr; i++) {
 901                 if (!packs.info[i].expired)
 902                         pack_name_concat_len += strlen(packs.info[i].pack_name) + 1;
 903         }
 904
 905         if (pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
 906                 pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
 907                                         (pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
 908
 909         hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
 910         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
 911         FREE_AND_NULL(midx_name);
 912
 913         if (packs.m)
 914                 close_midx(packs.m);
 915
 916         cur_chunk = 0;
 917         num_chunks = large_offsets_needed ? 5 : 4;
 918
 919         if (packs.nr - dropped_packs == 0) {
 920                 error(_("no pack files to index."));
 921                 result = 1;
 922                 goto cleanup;
 923         }
 924
 925         written = write_midx_header(f, num_chunks, packs.nr - dropped_packs);
 926
 927         chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES;
 928         chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
 929
 930         cur_chunk++;
 931         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT;
 932         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + pack_name_concat_len;
 933
 934         cur_chunk++;
 935         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
 936         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE;
 937
 938         cur_chunk++;
 939         chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
 940         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * the_hash_algo->rawsz;
 941
 942         cur_chunk++;
 943         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
 944         if (large_offsets_needed) {
 945                 chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS;
 946
 947                 cur_chunk++;
 948                 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] +
 949                                            num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH;
 950         }
 951
 952         chunk_ids[cur_chunk] = 0;
 953
 954         for (i = 0; i <= num_chunks; i++) {
 955                 if (i && chunk_offsets[i] < chunk_offsets[i - 1])
 956                         BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
 957                             chunk_offsets[i - 1],
 958                             chunk_offsets[i]);
 959
 960                 if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT)
 961                         BUG("chunk offset %"PRIu64" is not properly aligned",
 962                             chunk_offsets[i]);
 963
 964                 hashwrite_be32(f, chunk_ids[i]);
 965                 hashwrite_be32(f, chunk_offsets[i] >> 32);
 966                 hashwrite_be32(f, chunk_offsets[i]);
 967
 968                 written += MIDX_CHUNKLOOKUP_WIDTH;
 969         }
 970
 971         if (flags & MIDX_PROGRESS)
 972                 progress = start_delayed_progress(_("Writing chunks to multi-pack-index"),
 973                                           num_chunks);
 974         for (i = 0; i < num_chunks; i++) {
 975                 if (written != chunk_offsets[i])
 976                         BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
 977                             chunk_offsets[i],
 978                             written,
 979                             chunk_ids[i]);
 980
 981                 switch (chunk_ids[i]) {
 982                         case MIDX_CHUNKID_PACKNAMES:
 983                                 written += write_midx_pack_names(f, packs.info, packs.nr);
 984                                 break;
 985
 986                         case MIDX_CHUNKID_OIDFANOUT:
 987                                 written += write_midx_oid_fanout(f, entries, nr_entries);
 988                                 break;
 989
 990                         case MIDX_CHUNKID_OIDLOOKUP:
 991                                 written += write_midx_oid_lookup(f, the_hash_algo->rawsz, entries, nr_entries);
 992                                 break;
 993
 994                         case MIDX_CHUNKID_OBJECTOFFSETS:
 995                                 written += write_midx_object_offsets(f, large_offsets_needed, pack_perm, entries, nr_entries);
 996                                 break;
 997
 998                         case MIDX_CHUNKID_LARGEOFFSETS:
 999                                 written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries);
1000                                 break;
1001
1002                         default:
1003                                 BUG("trying to write unknown chunk id %"PRIx32,
1004                                     chunk_ids[i]);
1005                 }
1006
1007                 display_progress(progress, i + 1);
1008         }
1009         stop_progress(&progress);
1010
1011         if (written != chunk_offsets[num_chunks])
1012                 BUG("incorrect final offset %"PRIu64" != %"PRIu64,
1013                     written,
1014                     chunk_offsets[num_chunks]);
1015
1016         finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
1017         commit_lock_file(&lk);
1018
1019 cleanup:
1020         for (i = 0; i < packs.nr; i++) {
1021                 if (packs.info[i].p) {
1022                         close_pack(packs.info[i].p);
1023                         free(packs.info[i].p);
1024                 }
1025                 free(packs.info[i].pack_name);
1026         }
1027
1028         free(packs.info);
1029         free(entries);
1030         free(pack_perm);
1031         free(midx_name);
1032         return result;
1033 }
1034
1035 int write_midx_file(const char *object_dir, unsigned flags)
1036 {
1037         return write_midx_internal(object_dir, NULL, NULL, flags);
1038 }
1039
1040 void clear_midx_file(struct repository *r)
1041 {
1042         char *midx = get_midx_filename(r->objects->odb->path);
1043
1044         if (r->objects && r->objects->multi_pack_index) {
1045                 close_midx(r->objects->multi_pack_index);
1046                 r->objects->multi_pack_index = NULL;
1047         }
1048
1049         if (remove_path(midx)) {
1050                 UNLEAK(midx);
1051                 die(_("failed to clear multi-pack-index at %s"), midx);
1052         }
1053
1054         free(midx);
1055 }
1056
1057 static int verify_midx_error;
1058
1059 static void midx_report(const char *fmt, ...)
1060 {
1061         va_list ap;
1062         verify_midx_error = 1;
1063         va_start(ap, fmt);
1064         vfprintf(stderr, fmt, ap);
1065         fprintf(stderr, "\n");
1066         va_end(ap);
1067 }
1068
1069 struct pair_pos_vs_id
1070 {
1071         uint32_t pos;
1072         uint32_t pack_int_id;
1073 };
1074
1075 static int compare_pair_pos_vs_id(const void *_a, const void *_b)
1076 {
1077         struct pair_pos_vs_id *a = (struct pair_pos_vs_id *)_a;
1078         struct pair_pos_vs_id *b = (struct pair_pos_vs_id *)_b;
1079
1080         return b->pack_int_id - a->pack_int_id;
1081 }
1082
1083 /*
1084  * Limit calls to display_progress() for performance reasons.
1085  * The interval here was arbitrarily chosen.
1086  */
1087 #define SPARSE_PROGRESS_INTERVAL (1 << 12)
1088 #define midx_display_sparse_progress(progress, n) \
1089         do { \
1090                 uint64_t _n = (n); \
1091                 if ((_n & (SPARSE_PROGRESS_INTERVAL - 1)) == 0) \
1092                         display_progress(progress, _n); \
1093         } while (0)
1094
1095 int verify_midx_file(struct repository *r, const char *object_dir, unsigned flags)
1096 {
1097         struct pair_pos_vs_id *pairs = NULL;
1098         uint32_t i;
1099         struct progress *progress = NULL;
1100         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
1101         verify_midx_error = 0;
1102
1103         if (!m)
1104                 return 0;
1105
1106         if (flags & MIDX_PROGRESS)
1107                 progress = start_delayed_progress(_("Looking for referenced packfiles"),
1108                                           m->num_packs);
1109         for (i = 0; i < m->num_packs; i++) {
1110                 if (prepare_midx_pack(r, m, i))
1111                         midx_report("failed to load pack in position %d", i);
1112
1113                 display_progress(progress, i + 1);
1114         }
1115         stop_progress(&progress);
1116
1117         for (i = 0; i < 255; i++) {
1118                 uint32_t oid_fanout1 = ntohl(m->chunk_oid_fanout[i]);
1119                 uint32_t oid_fanout2 = ntohl(m->chunk_oid_fanout[i + 1]);
1120
1121                 if (oid_fanout1 > oid_fanout2)
1122                         midx_report(_("oid fanout out of order: fanout[%d] = %"PRIx32" > %"PRIx32" = fanout[%d]"),
1123                                     i, oid_fanout1, oid_fanout2, i + 1);
1124         }
1125
1126         if (m->num_objects == 0) {
1127                 midx_report(_("the midx contains no oid"));
1128                 /*
1129                  * Remaining tests assume that we have objects, so we can
1130                  * return here.
1131                  */
1132                 return verify_midx_error;
1133         }
1134
1135         if (flags & MIDX_PROGRESS)
1136                 progress = start_sparse_progress(_("Verifying OID order in multi-pack-index"),
1137                                                  m->num_objects - 1);
1138         for (i = 0; i < m->num_objects - 1; i++) {
1139                 struct object_id oid1, oid2;
1140
1141                 nth_midxed_object_oid(&oid1, m, i);
1142                 nth_midxed_object_oid(&oid2, m, i + 1);
1143
1144                 if (oidcmp(&oid1, &oid2) >= 0)
1145                         midx_report(_("oid lookup out of order: oid[%d] = %s >= %s = oid[%d]"),
1146                                     i, oid_to_hex(&oid1), oid_to_hex(&oid2), i + 1);
1147
1148                 midx_display_sparse_progress(progress, i + 1);
1149         }
1150         stop_progress(&progress);
1151
1152         /*
1153          * Create an array mapping each object to its packfile id.  Sort it
1154          * to group the objects by packfile.  Use this permutation to visit
1155          * each of the objects and only require 1 packfile to be open at a
1156          * time.
1157          */
1158         ALLOC_ARRAY(pairs, m->num_objects);
1159         for (i = 0; i < m->num_objects; i++) {
1160                 pairs[i].pos = i;
1161                 pairs[i].pack_int_id = nth_midxed_pack_int_id(m, i);
1162         }
1163
1164         if (flags & MIDX_PROGRESS)
1165                 progress = start_sparse_progress(_("Sorting objects by packfile"),
1166                                                  m->num_objects);
1167         display_progress(progress, 0); /* TODO: Measure QSORT() progress */
1168         QSORT(pairs, m->num_objects, compare_pair_pos_vs_id);
1169         stop_progress(&progress);
1170
1171         if (flags & MIDX_PROGRESS)
1172                 progress = start_sparse_progress(_("Verifying object offsets"), m->num_objects);
1173         for (i = 0; i < m->num_objects; i++) {
1174                 struct object_id oid;
1175                 struct pack_entry e;
1176                 off_t m_offset, p_offset;
1177
1178                 if (i > 0 && pairs[i-1].pack_int_id != pairs[i].pack_int_id &&
1179                     m->packs[pairs[i-1].pack_int_id])
1180                 {
1181                         close_pack_fd(m->packs[pairs[i-1].pack_int_id]);
1182                         close_pack_index(m->packs[pairs[i-1].pack_int_id]);
1183                 }
1184
1185                 nth_midxed_object_oid(&oid, m, pairs[i].pos);
1186
1187                 if (!fill_midx_entry(r, &oid, &e, m)) {
1188                         midx_report(_("failed to load pack entry for oid[%d] = %s"),
1189                                     pairs[i].pos, oid_to_hex(&oid));
1190                         continue;
1191                 }
1192
1193                 if (open_pack_index(e.p)) {
1194                         midx_report(_("failed to load pack-index for packfile %s"),
1195                                     e.p->pack_name);
1196                         break;
1197                 }
1198
1199                 m_offset = e.offset;
1200                 p_offset = find_pack_entry_one(oid.hash, e.p);
1201
1202                 if (m_offset != p_offset)
1203                         midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
1204                                     pairs[i].pos, oid_to_hex(&oid), m_offset, p_offset);
1205
1206                 midx_display_sparse_progress(progress, i + 1);
1207         }
1208         stop_progress(&progress);
1209
1210         free(pairs);
1211
1212         return verify_midx_error;
1213 }
1214
1215 int expire_midx_packs(struct repository *r, const char *object_dir, unsigned flags)
1216 {
1217         uint32_t i, *count, result = 0;
1218         struct string_list packs_to_drop = STRING_LIST_INIT_DUP;
1219         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
1220         struct progress *progress = NULL;
1221
1222         if (!m)
1223                 return 0;
1224
1225         count = xcalloc(m->num_packs, sizeof(uint32_t));
1226
1227         if (flags & MIDX_PROGRESS)
1228                 progress = start_delayed_progress(_("Counting referenced objects"),
1229                                           m->num_objects);
1230         for (i = 0; i < m->num_objects; i++) {
1231                 int pack_int_id = nth_midxed_pack_int_id(m, i);
1232                 count[pack_int_id]++;
1233                 display_progress(progress, i + 1);
1234         }
1235         stop_progress(&progress);
1236
1237         if (flags & MIDX_PROGRESS)
1238                 progress = start_delayed_progress(_("Finding and deleting unreferenced packfiles"),
1239                                           m->num_packs);
1240         for (i = 0; i < m->num_packs; i++) {
1241                 char *pack_name;
1242                 display_progress(progress, i + 1);
1243
1244                 if (count[i])
1245                         continue;
1246
1247                 if (prepare_midx_pack(r, m, i))
1248                         continue;
1249
1250                 if (m->packs[i]->pack_keep)
1251                         continue;
1252
1253                 pack_name = xstrdup(m->packs[i]->pack_name);
1254                 close_pack(m->packs[i]);
1255
1256                 string_list_insert(&packs_to_drop, m->pack_names[i]);
1257                 unlink_pack_path(pack_name, 0);
1258                 free(pack_name);
1259         }
1260         stop_progress(&progress);
1261
1262         free(count);
1263
1264         if (packs_to_drop.nr)
1265                 result = write_midx_internal(object_dir, m, &packs_to_drop, flags);
1266
1267         string_list_clear(&packs_to_drop, 0);
1268         return result;
1269 }
1270
1271 struct repack_info {
1272         timestamp_t mtime;
1273         uint32_t referenced_objects;
1274         uint32_t pack_int_id;
1275 };
1276
1277 static int compare_by_mtime(const void *a_, const void *b_)
1278 {
1279         const struct repack_info *a, *b;
1280
1281         a = (const struct repack_info *)a_;
1282         b = (const struct repack_info *)b_;
1283
1284         if (a->mtime < b->mtime)
1285                 return -1;
1286         if (a->mtime > b->mtime)
1287                 return 1;
1288         return 0;
1289 }
1290
1291 static int fill_included_packs_all(struct repository *r,
1292                                    struct multi_pack_index *m,
1293                                    unsigned char *include_pack)
1294 {
1295         uint32_t i, count = 0;
1296         int pack_kept_objects = 0;
1297
1298         repo_config_get_bool(r, "repack.packkeptobjects", &pack_kept_objects);
1299
1300         for (i = 0; i < m->num_packs; i++) {
1301                 if (prepare_midx_pack(r, m, i))
1302                         continue;
1303                 if (!pack_kept_objects && m->packs[i]->pack_keep)
1304                         continue;
1305
1306                 include_pack[i] = 1;
1307                 count++;
1308         }
1309
1310         return count < 2;
1311 }
1312
1313 static int fill_included_packs_batch(struct repository *r,
1314                                      struct multi_pack_index *m,
1315                                      unsigned char *include_pack,
1316                                      size_t batch_size)
1317 {
1318         uint32_t i, packs_to_repack;
1319         size_t total_size;
1320         struct repack_info *pack_info = xcalloc(m->num_packs, sizeof(struct repack_info));
1321         int pack_kept_objects = 0;
1322
1323         repo_config_get_bool(r, "repack.packkeptobjects", &pack_kept_objects);
1324
1325         for (i = 0; i < m->num_packs; i++) {
1326                 pack_info[i].pack_int_id = i;
1327
1328                 if (prepare_midx_pack(r, m, i))
1329                         continue;
1330
1331                 pack_info[i].mtime = m->packs[i]->mtime;
1332         }
1333
1334         for (i = 0; batch_size && i < m->num_objects; i++) {
1335                 uint32_t pack_int_id = nth_midxed_pack_int_id(m, i);
1336                 pack_info[pack_int_id].referenced_objects++;
1337         }
1338
1339         QSORT(pack_info, m->num_packs, compare_by_mtime);
1340
1341         total_size = 0;
1342         packs_to_repack = 0;
1343         for (i = 0; total_size < batch_size && i < m->num_packs; i++) {
1344                 int pack_int_id = pack_info[i].pack_int_id;
1345                 struct packed_git *p = m->packs[pack_int_id];
1346                 size_t expected_size;
1347
1348                 if (!p)
1349                         continue;
1350                 if (!pack_kept_objects && p->pack_keep)
1351                         continue;
1352                 if (open_pack_index(p) || !p->num_objects)
1353                         continue;
1354
1355                 expected_size = (size_t)(p->pack_size
1356                                          * pack_info[i].referenced_objects);
1357                 expected_size /= p->num_objects;
1358
1359                 if (expected_size >= batch_size)
1360                         continue;
1361
1362                 packs_to_repack++;
1363                 total_size += expected_size;
1364                 include_pack[pack_int_id] = 1;
1365         }
1366
1367         free(pack_info);
1368
1369         if (total_size < batch_size || packs_to_repack < 2)
1370                 return 1;
1371
1372         return 0;
1373 }
1374
1375 int midx_repack(struct repository *r, const char *object_dir, size_t batch_size, unsigned flags)
1376 {
1377         int result = 0;
1378         uint32_t i;
1379         unsigned char *include_pack;
1380         struct child_process cmd = CHILD_PROCESS_INIT;
1381         struct strbuf base_name = STRBUF_INIT;
1382         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
1383
1384         /*
1385          * When updating the default for these configuration
1386          * variables in builtin/repack.c, these must be adjusted
1387          * to match.
1388          */
1389         int delta_base_offset = 1;
1390         int use_delta_islands = 0;
1391
1392         if (!m)
1393                 return 0;
1394
1395         include_pack = xcalloc(m->num_packs, sizeof(unsigned char));
1396
1397         if (batch_size) {
1398                 if (fill_included_packs_batch(r, m, include_pack, batch_size))
1399                         goto cleanup;
1400         } else if (fill_included_packs_all(r, m, include_pack))
1401                 goto cleanup;
1402
1403         repo_config_get_bool(r, "repack.usedeltabaseoffset", &delta_base_offset);
1404         repo_config_get_bool(r, "repack.usedeltaislands", &use_delta_islands);
1405
1406         strvec_push(&cmd.args, "pack-objects");
1407
1408         strbuf_addstr(&base_name, object_dir);
1409         strbuf_addstr(&base_name, "/pack/pack");
1410         strvec_push(&cmd.args, base_name.buf);
1411
1412         if (delta_base_offset)
1413                 strvec_push(&cmd.args, "--delta-base-offset");
1414         if (use_delta_islands)
1415                 strvec_push(&cmd.args, "--delta-islands");
1416
1417         if (flags & MIDX_PROGRESS)
1418                 strvec_push(&cmd.args, "--progress");
1419         else
1420                 strvec_push(&cmd.args, "-q");
1421
1422         strbuf_release(&base_name);
1423
1424         cmd.git_cmd = 1;
1425         cmd.in = cmd.out = -1;
1426
1427         if (start_command(&cmd)) {
1428                 error(_("could not start pack-objects"));
1429                 result = 1;
1430                 goto cleanup;
1431         }
1432
1433         for (i = 0; i < m->num_objects; i++) {
1434                 struct object_id oid;
1435                 uint32_t pack_int_id = nth_midxed_pack_int_id(m, i);
1436
1437                 if (!include_pack[pack_int_id])
1438                         continue;
1439
1440                 nth_midxed_object_oid(&oid, m, i);
1441                 xwrite(cmd.in, oid_to_hex(&oid), the_hash_algo->hexsz);
1442                 xwrite(cmd.in, "\n", 1);
1443         }
1444         close(cmd.in);
1445
1446         if (finish_command(&cmd)) {
1447                 error(_("could not finish pack-objects"));
1448                 result = 1;
1449                 goto cleanup;
1450         }
1451
1452         result = write_midx_internal(object_dir, m, NULL, flags);
1453         m = NULL;
1454
1455 cleanup:
1456         if (m)
1457                 close_midx(m);
1458         free(include_pack);
1459         return result;
1460 }