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 "hash-lookup.h"
   9 #include "midx.h"
  10 #include "progress.h"
  11 #include "trace2.h"
  12 #include "run-command.h"
  13 #include "repository.h"
  14 #include "chunk-format.h"
  15
  16 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
  17 #define MIDX_VERSION 1
  18 #define MIDX_BYTE_FILE_VERSION 4
  19 #define MIDX_BYTE_HASH_VERSION 5
  20 #define MIDX_BYTE_NUM_CHUNKS 6
  21 #define MIDX_BYTE_NUM_PACKS 8
  22 #define MIDX_HEADER_SIZE 12
  23 #define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + the_hash_algo->rawsz)
  24
  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_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
  32 #define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
  33 #define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
  34 #define MIDX_LARGE_OFFSET_NEEDED 0x80000000
  35
  36 #define PACK_EXPIRED UINT_MAX
  37
  38 static uint8_t oid_version(void)
  39 {
  40         switch (hash_algo_by_ptr(the_hash_algo)) {
  41         case GIT_HASH_SHA1:
  42                 return 1;
  43         case GIT_HASH_SHA256:
  44                 return 2;
  45         default:
  46                 die(_("invalid hash version"));
  47         }
  48 }
  49
  50 static char *get_midx_filename(const char *object_dir)
  51 {
  52         return xstrfmt("%s/pack/multi-pack-index", object_dir);
  53 }
  54
  55 static int midx_read_oid_fanout(const unsigned char *chunk_start,
  56                                 size_t chunk_size, void *data)
  57 {
  58         struct multi_pack_index *m = data;
  59         m->chunk_oid_fanout = (uint32_t *)chunk_start;
  60
  61         if (chunk_size != 4 * 256) {
  62                 error(_("multi-pack-index OID fanout is of the wrong size"));
  63                 return 1;
  64         }
  65         return 0;
  66 }
  67
  68 struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
  69 {
  70         struct multi_pack_index *m = NULL;
  71         int fd;
  72         struct stat st;
  73         size_t midx_size;
  74         void *midx_map = NULL;
  75         uint32_t hash_version;
  76         char *midx_name = get_midx_filename(object_dir);
  77         uint32_t i;
  78         const char *cur_pack_name;
  79         struct chunkfile *cf = NULL;
  80
  81         fd = git_open(midx_name);
  82
  83         if (fd < 0)
  84                 goto cleanup_fail;
  85         if (fstat(fd, &st)) {
  86                 error_errno(_("failed to read %s"), midx_name);
  87                 goto cleanup_fail;
  88         }
  89
  90         midx_size = xsize_t(st.st_size);
  91
  92         if (midx_size < MIDX_MIN_SIZE) {
  93                 error(_("multi-pack-index file %s is too small"), midx_name);
  94                 goto cleanup_fail;
  95         }
  96
  97         FREE_AND_NULL(midx_name);
  98
  99         midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 100         close(fd);
 101
 102         FLEX_ALLOC_STR(m, object_dir, object_dir);
 103         m->data = midx_map;
 104         m->data_len = midx_size;
 105         m->local = local;
 106
 107         m->signature = get_be32(m->data);
 108         if (m->signature != MIDX_SIGNATURE)
 109                 die(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
 110                       m->signature, MIDX_SIGNATURE);
 111
 112         m->version = m->data[MIDX_BYTE_FILE_VERSION];
 113         if (m->version != MIDX_VERSION)
 114                 die(_("multi-pack-index version %d not recognized"),
 115                       m->version);
 116
 117         hash_version = m->data[MIDX_BYTE_HASH_VERSION];
 118         if (hash_version != oid_version()) {
 119                 error(_("multi-pack-index hash version %u does not match version %u"),
 120                       hash_version, oid_version());
 121                 goto cleanup_fail;
 122         }
 123         m->hash_len = the_hash_algo->rawsz;
 124
 125         m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
 126
 127         m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
 128
 129         cf = init_chunkfile(NULL);
 130
 131         if (read_table_of_contents(cf, m->data, midx_size,
 132                                    MIDX_HEADER_SIZE, m->num_chunks))
 133                 goto cleanup_fail;
 134
 135         if (pair_chunk(cf, MIDX_CHUNKID_PACKNAMES, &m->chunk_pack_names) == CHUNK_NOT_FOUND)
 136                 die(_("multi-pack-index missing required pack-name chunk"));
 137         if (read_chunk(cf, MIDX_CHUNKID_OIDFANOUT, midx_read_oid_fanout, m) == CHUNK_NOT_FOUND)
 138                 die(_("multi-pack-index missing required OID fanout chunk"));
 139         if (pair_chunk(cf, MIDX_CHUNKID_OIDLOOKUP, &m->chunk_oid_lookup) == CHUNK_NOT_FOUND)
 140                 die(_("multi-pack-index missing required OID lookup chunk"));
 141         if (pair_chunk(cf, MIDX_CHUNKID_OBJECTOFFSETS, &m->chunk_object_offsets) == CHUNK_NOT_FOUND)
 142                 die(_("multi-pack-index missing required object offsets chunk"));
 143
 144         pair_chunk(cf, MIDX_CHUNKID_LARGEOFFSETS, &m->chunk_large_offsets);
 145
 146         m->num_objects = ntohl(m->chunk_oid_fanout[255]);
 147
 148         m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
 149         m->packs = xcalloc(m->num_packs, sizeof(*m->packs));
 150
 151         cur_pack_name = (const char *)m->chunk_pack_names;
 152         for (i = 0; i < m->num_packs; i++) {
 153                 m->pack_names[i] = cur_pack_name;
 154
 155                 cur_pack_name += strlen(cur_pack_name) + 1;
 156
 157                 if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0)
 158                         die(_("multi-pack-index pack names out of order: '%s' before '%s'"),
 159                               m->pack_names[i - 1],
 160                               m->pack_names[i]);
 161         }
 162
 163         trace2_data_intmax("midx", the_repository, "load/num_packs", m->num_packs);
 164         trace2_data_intmax("midx", the_repository, "load/num_objects", m->num_objects);
 165
 166         return m;
 167
 168 cleanup_fail:
 169         free(m);
 170         free(midx_name);
 171         free(cf);
 172         if (midx_map)
 173                 munmap(midx_map, midx_size);
 174         if (0 <= fd)
 175                 close(fd);
 176         return NULL;
 177 }
 178
 179 void close_midx(struct multi_pack_index *m)
 180 {
 181         uint32_t i;
 182
 183         if (!m)
 184                 return;
 185
 186         munmap((unsigned char *)m->data, m->data_len);
 187
 188         for (i = 0; i < m->num_packs; i++) {
 189                 if (m->packs[i])
 190                         m->packs[i]->multi_pack_index = 0;
 191         }
 192         FREE_AND_NULL(m->packs);
 193         FREE_AND_NULL(m->pack_names);
 194 }
 195
 196 int prepare_midx_pack(struct repository *r, struct multi_pack_index *m, uint32_t pack_int_id)
 197 {
 198         struct strbuf pack_name = STRBUF_INIT;
 199         struct packed_git *p;
 200
 201         if (pack_int_id >= m->num_packs)
 202                 die(_("bad pack-int-id: %u (%u total packs)"),
 203                     pack_int_id, m->num_packs);
 204
 205         if (m->packs[pack_int_id])
 206                 return 0;
 207
 208         strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
 209                     m->pack_names[pack_int_id]);
 210
 211         p = add_packed_git(pack_name.buf, pack_name.len, m->local);
 212         strbuf_release(&pack_name);
 213
 214         if (!p)
 215                 return 1;
 216
 217         p->multi_pack_index = 1;
 218         m->packs[pack_int_id] = p;
 219         install_packed_git(r, p);
 220         list_add_tail(&p->mru, &r->objects->packed_git_mru);
 221
 222         return 0;
 223 }
 224
 225 int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
 226 {
 227         return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
 228                             the_hash_algo->rawsz, result);
 229 }
 230
 231 struct object_id *nth_midxed_object_oid(struct object_id *oid,
 232                                         struct multi_pack_index *m,
 233                                         uint32_t n)
 234 {
 235         if (n >= m->num_objects)
 236                 return NULL;
 237
 238         hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
 239         return oid;
 240 }
 241
 242 static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
 243 {
 244         const unsigned char *offset_data;
 245         uint32_t offset32;
 246
 247         offset_data = m->chunk_object_offsets + (off_t)pos * MIDX_CHUNK_OFFSET_WIDTH;
 248         offset32 = get_be32(offset_data + sizeof(uint32_t));
 249
 250         if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
 251                 if (sizeof(off_t) < sizeof(uint64_t))
 252                         die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
 253
 254                 offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
 255                 return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
 256         }
 257
 258         return offset32;
 259 }
 260
 261 static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
 262 {
 263         return get_be32(m->chunk_object_offsets +
 264                         (off_t)pos * MIDX_CHUNK_OFFSET_WIDTH);
 265 }
 266
 267 static int nth_midxed_pack_entry(struct repository *r,
 268                                  struct multi_pack_index *m,
 269                                  struct pack_entry *e,
 270                                  uint32_t pos)
 271 {
 272         uint32_t pack_int_id;
 273         struct packed_git *p;
 274
 275         if (pos >= m->num_objects)
 276                 return 0;
 277
 278         pack_int_id = nth_midxed_pack_int_id(m, pos);
 279
 280         if (prepare_midx_pack(r, m, pack_int_id))
 281                 return 0;
 282         p = m->packs[pack_int_id];
 283
 284         /*
 285         * We are about to tell the caller where they can locate the
 286         * requested object.  We better make sure the packfile is
 287         * still here and can be accessed before supplying that
 288         * answer, as it may have been deleted since the MIDX was
 289         * loaded!
 290         */
 291         if (!is_pack_valid(p))
 292                 return 0;
 293
 294         if (p->num_bad_objects) {
 295                 uint32_t i;
 296                 struct object_id oid;
 297                 nth_midxed_object_oid(&oid, m, pos);
 298                 for (i = 0; i < p->num_bad_objects; i++)
 299                         if (hasheq(oid.hash,
 300                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
 301                                 return 0;
 302         }
 303
 304         e->offset = nth_midxed_offset(m, pos);
 305         e->p = p;
 306
 307         return 1;
 308 }
 309
 310 int fill_midx_entry(struct repository * r,
 311                     const struct object_id *oid,
 312                     struct pack_entry *e,
 313                     struct multi_pack_index *m)
 314 {
 315         uint32_t pos;
 316
 317         if (!bsearch_midx(oid, m, &pos))
 318                 return 0;
 319
 320         return nth_midxed_pack_entry(r, m, e, pos);
 321 }
 322
 323 /* Match "foo.idx" against either "foo.pack" _or_ "foo.idx". */
 324 static int cmp_idx_or_pack_name(const char *idx_or_pack_name,
 325                                 const char *idx_name)
 326 {
 327         /* Skip past any initial matching prefix. */
 328         while (*idx_name && *idx_name == *idx_or_pack_name) {
 329                 idx_name++;
 330                 idx_or_pack_name++;
 331         }
 332
 333         /*
 334          * If we didn't match completely, we may have matched "pack-1234." and
 335          * be left with "idx" and "pack" respectively, which is also OK. We do
 336          * not have to check for "idx" and "idx", because that would have been
 337          * a complete match (and in that case these strcmps will be false, but
 338          * we'll correctly return 0 from the final strcmp() below.
 339          *
 340          * Technically this matches "fooidx" and "foopack", but we'd never have
 341          * such names in the first place.
 342          */
 343         if (!strcmp(idx_name, "idx") && !strcmp(idx_or_pack_name, "pack"))
 344                 return 0;
 345
 346         /*
 347          * This not only checks for a complete match, but also orders based on
 348          * the first non-identical character, which means our ordering will
 349          * match a raw strcmp(). That makes it OK to use this to binary search
 350          * a naively-sorted list.
 351          */
 352         return strcmp(idx_or_pack_name, idx_name);
 353 }
 354
 355 int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name)
 356 {
 357         uint32_t first = 0, last = m->num_packs;
 358
 359         while (first < last) {
 360                 uint32_t mid = first + (last - first) / 2;
 361                 const char *current;
 362                 int cmp;
 363
 364                 current = m->pack_names[mid];
 365                 cmp = cmp_idx_or_pack_name(idx_or_pack_name, current);
 366                 if (!cmp)
 367                         return 1;
 368                 if (cmp > 0) {
 369                         first = mid + 1;
 370                         continue;
 371                 }
 372                 last = mid;
 373         }
 374
 375         return 0;
 376 }
 377
 378 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local)
 379 {
 380         struct multi_pack_index *m;
 381         struct multi_pack_index *m_search;
 382
 383         prepare_repo_settings(r);
 384         if (!r->settings.core_multi_pack_index)
 385                 return 0;
 386
 387         for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
 388                 if (!strcmp(object_dir, m_search->object_dir))
 389                         return 1;
 390
 391         m = load_multi_pack_index(object_dir, local);
 392
 393         if (m) {
 394                 struct multi_pack_index *mp = r->objects->multi_pack_index;
 395                 if (mp) {
 396                         m->next = mp->next;
 397                         mp->next = m;
 398                 } else
 399                         r->objects->multi_pack_index = m;
 400                 return 1;
 401         }
 402
 403         return 0;
 404 }
 405
 406 static size_t write_midx_header(struct hashfile *f,
 407                                 unsigned char num_chunks,
 408                                 uint32_t num_packs)
 409 {
 410         hashwrite_be32(f, MIDX_SIGNATURE);
 411         hashwrite_u8(f, MIDX_VERSION);
 412         hashwrite_u8(f, oid_version());
 413         hashwrite_u8(f, num_chunks);
 414         hashwrite_u8(f, 0); /* unused */
 415         hashwrite_be32(f, num_packs);
 416
 417         return MIDX_HEADER_SIZE;
 418 }
 419
 420 struct pack_info {
 421         uint32_t orig_pack_int_id;
 422         char *pack_name;
 423         struct packed_git *p;
 424         unsigned expired : 1;
 425 };
 426
 427 static int pack_info_compare(const void *_a, const void *_b)
 428 {
 429         struct pack_info *a = (struct pack_info *)_a;
 430         struct pack_info *b = (struct pack_info *)_b;
 431         return strcmp(a->pack_name, b->pack_name);
 432 }
 433
 434 static int idx_or_pack_name_cmp(const void *_va, const void *_vb)
 435 {
 436         const char *pack_name = _va;
 437         const struct pack_info *compar = _vb;
 438
 439         return cmp_idx_or_pack_name(pack_name, compar->pack_name);
 440 }
 441
 442 struct write_midx_context {
 443         struct pack_info *info;
 444         uint32_t nr;
 445         uint32_t alloc;
 446         struct multi_pack_index *m;
 447         struct progress *progress;
 448         unsigned pack_paths_checked;
 449
 450         struct pack_midx_entry *entries;
 451         uint32_t entries_nr;
 452
 453         uint32_t *pack_perm;
 454         unsigned large_offsets_needed:1;
 455         uint32_t num_large_offsets;
 456
 457         int preferred_pack_idx;
 458 };
 459
 460 static void add_pack_to_midx(const char *full_path, size_t full_path_len,
 461                              const char *file_name, void *data)
 462 {
 463         struct write_midx_context *ctx = data;
 464
 465         if (ends_with(file_name, ".idx")) {
 466                 display_progress(ctx->progress, ++ctx->pack_paths_checked);
 467                 if (ctx->m && midx_contains_pack(ctx->m, file_name))
 468                         return;
 469
 470                 ALLOC_GROW(ctx->info, ctx->nr + 1, ctx->alloc);
 471
 472                 ctx->info[ctx->nr].p = add_packed_git(full_path,
 473                                                       full_path_len,
 474                                                       0);
 475
 476                 if (!ctx->info[ctx->nr].p) {
 477                         warning(_("failed to add packfile '%s'"),
 478                                 full_path);
 479                         return;
 480                 }
 481
 482                 if (open_pack_index(ctx->info[ctx->nr].p)) {
 483                         warning(_("failed to open pack-index '%s'"),
 484                                 full_path);
 485                         close_pack(ctx->info[ctx->nr].p);
 486                         FREE_AND_NULL(ctx->info[ctx->nr].p);
 487                         return;
 488                 }
 489
 490                 ctx->info[ctx->nr].pack_name = xstrdup(file_name);
 491                 ctx->info[ctx->nr].orig_pack_int_id = ctx->nr;
 492                 ctx->info[ctx->nr].expired = 0;
 493                 ctx->nr++;
 494         }
 495 }
 496
 497 struct pack_midx_entry {
 498         struct object_id oid;
 499         uint32_t pack_int_id;
 500         time_t pack_mtime;
 501         uint64_t offset;
 502         unsigned preferred : 1;
 503 };
 504
 505 static int midx_oid_compare(const void *_a, const void *_b)
 506 {
 507         const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
 508         const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
 509         int cmp = oidcmp(&a->oid, &b->oid);
 510
 511         if (cmp)
 512                 return cmp;
 513
 514         /* Sort objects in a preferred pack first when multiple copies exist. */
 515         if (a->preferred > b->preferred)
 516                 return -1;
 517         if (a->preferred < b->preferred)
 518                 return 1;
 519
 520         if (a->pack_mtime > b->pack_mtime)
 521                 return -1;
 522         else if (a->pack_mtime < b->pack_mtime)
 523                 return 1;
 524
 525         return a->pack_int_id - b->pack_int_id;
 526 }
 527
 528 static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
 529                                       struct pack_midx_entry *e,
 530                                       uint32_t pos)
 531 {
 532         if (pos >= m->num_objects)
 533                 return 1;
 534
 535         nth_midxed_object_oid(&e->oid, m, pos);
 536         e->pack_int_id = nth_midxed_pack_int_id(m, pos);
 537         e->offset = nth_midxed_offset(m, pos);
 538
 539         /* consider objects in midx to be from "old" packs */
 540         e->pack_mtime = 0;
 541         return 0;
 542 }
 543
 544 static void fill_pack_entry(uint32_t pack_int_id,
 545                             struct packed_git *p,
 546                             uint32_t cur_object,
 547                             struct pack_midx_entry *entry,
 548                             int preferred)
 549 {
 550         if (nth_packed_object_id(&entry->oid, p, cur_object) < 0)
 551                 die(_("failed to locate object %d in packfile"), cur_object);
 552
 553         entry->pack_int_id = pack_int_id;
 554         entry->pack_mtime = p->mtime;
 555
 556         entry->offset = nth_packed_object_offset(p, cur_object);
 557         entry->preferred = !!preferred;
 558 }
 559
 560 /*
 561  * It is possible to artificially get into a state where there are many
 562  * duplicate copies of objects. That can create high memory pressure if
 563  * we are to create a list of all objects before de-duplication. To reduce
 564  * this memory pressure without a significant performance drop, automatically
 565  * group objects by the first byte of their object id. Use the IDX fanout
 566  * tables to group the data, copy to a local array, then sort.
 567  *
 568  * Copy only the de-duplicated entries (selected by most-recent modified time
 569  * of a packfile containing the object).
 570  */
 571 static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
 572                                                   struct pack_info *info,
 573                                                   uint32_t nr_packs,
 574                                                   uint32_t *nr_objects,
 575                                                   int preferred_pack)
 576 {
 577         uint32_t cur_fanout, cur_pack, cur_object;
 578         uint32_t alloc_fanout, alloc_objects, total_objects = 0;
 579         struct pack_midx_entry *entries_by_fanout = NULL;
 580         struct pack_midx_entry *deduplicated_entries = NULL;
 581         uint32_t start_pack = m ? m->num_packs : 0;
 582
 583         for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
 584                 total_objects += info[cur_pack].p->num_objects;
 585
 586         /*
 587          * As we de-duplicate by fanout value, we expect the fanout
 588          * slices to be evenly distributed, with some noise. Hence,
 589          * allocate slightly more than one 256th.
 590          */
 591         alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
 592
 593         ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
 594         ALLOC_ARRAY(deduplicated_entries, alloc_objects);
 595         *nr_objects = 0;
 596
 597         for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
 598                 uint32_t nr_fanout = 0;
 599
 600                 if (m) {
 601                         uint32_t start = 0, end;
 602
 603                         if (cur_fanout)
 604                                 start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
 605                         end = ntohl(m->chunk_oid_fanout[cur_fanout]);
 606
 607                         for (cur_object = start; cur_object < end; cur_object++) {
 608                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 609                                 nth_midxed_pack_midx_entry(m,
 610                                                            &entries_by_fanout[nr_fanout],
 611                                                            cur_object);
 612                                 if (nth_midxed_pack_int_id(m, cur_object) == preferred_pack)
 613                                         entries_by_fanout[nr_fanout].preferred = 1;
 614                                 else
 615                                         entries_by_fanout[nr_fanout].preferred = 0;
 616                                 nr_fanout++;
 617                         }
 618                 }
 619
 620                 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
 621                         uint32_t start = 0, end;
 622                         int preferred = cur_pack == preferred_pack;
 623
 624                         if (cur_fanout)
 625                                 start = get_pack_fanout(info[cur_pack].p, cur_fanout - 1);
 626                         end = get_pack_fanout(info[cur_pack].p, cur_fanout);
 627
 628                         for (cur_object = start; cur_object < end; cur_object++) {
 629                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 630                                 fill_pack_entry(cur_pack,
 631                                                 info[cur_pack].p,
 632                                                 cur_object,
 633                                                 &entries_by_fanout[nr_fanout],
 634                                                 preferred);
 635                                 nr_fanout++;
 636                         }
 637                 }
 638
 639                 QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
 640
 641                 /*
 642                  * The batch is now sorted by OID and then mtime (descending).
 643                  * Take only the first duplicate.
 644                  */
 645                 for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
 646                         if (cur_object && oideq(&entries_by_fanout[cur_object - 1].oid,
 647                                                 &entries_by_fanout[cur_object].oid))
 648                                 continue;
 649
 650                         ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
 651                         memcpy(&deduplicated_entries[*nr_objects],
 652                                &entries_by_fanout[cur_object],
 653                                sizeof(struct pack_midx_entry));
 654                         (*nr_objects)++;
 655                 }
 656         }
 657
 658         free(entries_by_fanout);
 659         return deduplicated_entries;
 660 }
 661
 662 static int write_midx_pack_names(struct hashfile *f, void *data)
 663 {
 664         struct write_midx_context *ctx = data;
 665         uint32_t i;
 666         unsigned char padding[MIDX_CHUNK_ALIGNMENT];
 667         size_t written = 0;
 668
 669         for (i = 0; i < ctx->nr; i++) {
 670                 size_t writelen;
 671
 672                 if (ctx->info[i].expired)
 673                         continue;
 674
 675                 if (i && strcmp(ctx->info[i].pack_name, ctx->info[i - 1].pack_name) <= 0)
 676                         BUG("incorrect pack-file order: %s before %s",
 677                             ctx->info[i - 1].pack_name,
 678                             ctx->info[i].pack_name);
 679
 680                 writelen = strlen(ctx->info[i].pack_name) + 1;
 681                 hashwrite(f, ctx->info[i].pack_name, writelen);
 682                 written += writelen;
 683         }
 684
 685         /* add padding to be aligned */
 686         i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
 687         if (i < MIDX_CHUNK_ALIGNMENT) {
 688                 memset(padding, 0, sizeof(padding));
 689                 hashwrite(f, padding, i);
 690         }
 691
 692         return 0;
 693 }
 694
 695 static int write_midx_oid_fanout(struct hashfile *f,
 696                                  void *data)
 697 {
 698         struct write_midx_context *ctx = data;
 699         struct pack_midx_entry *list = ctx->entries;
 700         struct pack_midx_entry *last = ctx->entries + ctx->entries_nr;
 701         uint32_t count = 0;
 702         uint32_t i;
 703
 704         /*
 705         * Write the first-level table (the list is sorted,
 706         * but we use a 256-entry lookup to be able to avoid
 707         * having to do eight extra binary search iterations).
 708         */
 709         for (i = 0; i < 256; i++) {
 710                 struct pack_midx_entry *next = list;
 711
 712                 while (next < last && next->oid.hash[0] == i) {
 713                         count++;
 714                         next++;
 715                 }
 716
 717                 hashwrite_be32(f, count);
 718                 list = next;
 719         }
 720
 721         return 0;
 722 }
 723
 724 static int write_midx_oid_lookup(struct hashfile *f,
 725                                  void *data)
 726 {
 727         struct write_midx_context *ctx = data;
 728         unsigned char hash_len = the_hash_algo->rawsz;
 729         struct pack_midx_entry *list = ctx->entries;
 730         uint32_t i;
 731
 732         for (i = 0; i < ctx->entries_nr; i++) {
 733                 struct pack_midx_entry *obj = list++;
 734
 735                 if (i < ctx->entries_nr - 1) {
 736                         struct pack_midx_entry *next = list;
 737                         if (oidcmp(&obj->oid, &next->oid) >= 0)
 738                                 BUG("OIDs not in order: %s >= %s",
 739                                     oid_to_hex(&obj->oid),
 740                                     oid_to_hex(&next->oid));
 741                 }
 742
 743                 hashwrite(f, obj->oid.hash, (int)hash_len);
 744         }
 745
 746         return 0;
 747 }
 748
 749 static int write_midx_object_offsets(struct hashfile *f,
 750                                      void *data)
 751 {
 752         struct write_midx_context *ctx = data;
 753         struct pack_midx_entry *list = ctx->entries;
 754         uint32_t i, nr_large_offset = 0;
 755
 756         for (i = 0; i < ctx->entries_nr; i++) {
 757                 struct pack_midx_entry *obj = list++;
 758
 759                 if (ctx->pack_perm[obj->pack_int_id] == PACK_EXPIRED)
 760                         BUG("object %s is in an expired pack with int-id %d",
 761                             oid_to_hex(&obj->oid),
 762                             obj->pack_int_id);
 763
 764                 hashwrite_be32(f, ctx->pack_perm[obj->pack_int_id]);
 765
 766                 if (ctx->large_offsets_needed && obj->offset >> 31)
 767                         hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
 768                 else if (!ctx->large_offsets_needed && obj->offset >> 32)
 769                         BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
 770                             oid_to_hex(&obj->oid),
 771                             obj->offset);
 772                 else
 773                         hashwrite_be32(f, (uint32_t)obj->offset);
 774         }
 775
 776         return 0;
 777 }
 778
 779 static int write_midx_large_offsets(struct hashfile *f,
 780                                     void *data)
 781 {
 782         struct write_midx_context *ctx = data;
 783         struct pack_midx_entry *list = ctx->entries;
 784         struct pack_midx_entry *end = ctx->entries + ctx->entries_nr;
 785         uint32_t nr_large_offset = ctx->num_large_offsets;
 786
 787         while (nr_large_offset) {
 788                 struct pack_midx_entry *obj;
 789                 uint64_t offset;
 790
 791                 if (list >= end)
 792                         BUG("too many large-offset objects");
 793
 794                 obj = list++;
 795                 offset = obj->offset;
 796
 797                 if (!(offset >> 31))
 798                         continue;
 799
 800                 hashwrite_be64(f, offset);
 801
 802                 nr_large_offset--;
 803         }
 804
 805         return 0;
 806 }
 807
 808 static int write_midx_internal(const char *object_dir, struct multi_pack_index *m,
 809                                struct string_list *packs_to_drop,
 810                                const char *preferred_pack_name,
 811                                unsigned flags)
 812 {
 813         char *midx_name;
 814         uint32_t i;
 815         struct hashfile *f = NULL;
 816         struct lock_file lk;
 817         struct write_midx_context ctx = { 0 };
 818         int pack_name_concat_len = 0;
 819         int dropped_packs = 0;
 820         int result = 0;
 821         struct chunkfile *cf;
 822
 823         midx_name = get_midx_filename(object_dir);
 824         if (safe_create_leading_directories(midx_name))
 825                 die_errno(_("unable to create leading directories of %s"),
 826                           midx_name);
 827
 828         if (m)
 829                 ctx.m = m;
 830         else
 831                 ctx.m = load_multi_pack_index(object_dir, 1);
 832
 833         ctx.nr = 0;
 834         ctx.alloc = ctx.m ? ctx.m->num_packs : 16;
 835         ctx.info = NULL;
 836         ALLOC_ARRAY(ctx.info, ctx.alloc);
 837
 838         if (ctx.m) {
 839                 for (i = 0; i < ctx.m->num_packs; i++) {
 840                         ALLOC_GROW(ctx.info, ctx.nr + 1, ctx.alloc);
 841
 842                         ctx.info[ctx.nr].orig_pack_int_id = i;
 843                         ctx.info[ctx.nr].pack_name = xstrdup(ctx.m->pack_names[i]);
 844                         ctx.info[ctx.nr].p = NULL;
 845                         ctx.info[ctx.nr].expired = 0;
 846                         ctx.nr++;
 847                 }
 848         }
 849
 850         ctx.pack_paths_checked = 0;
 851         if (flags & MIDX_PROGRESS)
 852                 ctx.progress = start_delayed_progress(_("Adding packfiles to multi-pack-index"), 0);
 853         else
 854                 ctx.progress = NULL;
 855
 856         for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &ctx);
 857         stop_progress(&ctx.progress);
 858
 859         if (ctx.m && ctx.nr == ctx.m->num_packs && !packs_to_drop)
 860                 goto cleanup;
 861
 862         ctx.preferred_pack_idx = -1;
 863         if (preferred_pack_name) {
 864                 for (i = 0; i < ctx.nr; i++) {
 865                         if (!cmp_idx_or_pack_name(preferred_pack_name,
 866                                                   ctx.info[i].pack_name)) {
 867                                 ctx.preferred_pack_idx = i;
 868                                 break;
 869                         }
 870                 }
 871         }
 872
 873         ctx.entries = get_sorted_entries(ctx.m, ctx.info, ctx.nr, &ctx.entries_nr,
 874                                          ctx.preferred_pack_idx);
 875
 876         ctx.large_offsets_needed = 0;
 877         for (i = 0; i < ctx.entries_nr; i++) {
 878                 if (ctx.entries[i].offset > 0x7fffffff)
 879                         ctx.num_large_offsets++;
 880                 if (ctx.entries[i].offset > 0xffffffff)
 881                         ctx.large_offsets_needed = 1;
 882         }
 883
 884         QSORT(ctx.info, ctx.nr, pack_info_compare);
 885
 886         if (packs_to_drop && packs_to_drop->nr) {
 887                 int drop_index = 0;
 888                 int missing_drops = 0;
 889
 890                 for (i = 0; i < ctx.nr && drop_index < packs_to_drop->nr; i++) {
 891                         int cmp = strcmp(ctx.info[i].pack_name,
 892                                          packs_to_drop->items[drop_index].string);
 893
 894                         if (!cmp) {
 895                                 drop_index++;
 896                                 ctx.info[i].expired = 1;
 897                         } else if (cmp > 0) {
 898                                 error(_("did not see pack-file %s to drop"),
 899                                       packs_to_drop->items[drop_index].string);
 900                                 drop_index++;
 901                                 missing_drops++;
 902                                 i--;
 903                         } else {
 904                                 ctx.info[i].expired = 0;
 905                         }
 906                 }
 907
 908                 if (missing_drops) {
 909                         result = 1;
 910                         goto cleanup;
 911                 }
 912         }
 913
 914         /*
 915          * pack_perm stores a permutation between pack-int-ids from the
 916          * previous multi-pack-index to the new one we are writing:
 917          *
 918          * pack_perm[old_id] = new_id
 919          */
 920         ALLOC_ARRAY(ctx.pack_perm, ctx.nr);
 921         for (i = 0; i < ctx.nr; i++) {
 922                 if (ctx.info[i].expired) {
 923                         dropped_packs++;
 924                         ctx.pack_perm[ctx.info[i].orig_pack_int_id] = PACK_EXPIRED;
 925                 } else {
 926                         ctx.pack_perm[ctx.info[i].orig_pack_int_id] = i - dropped_packs;
 927                 }
 928         }
 929
 930         for (i = 0; i < ctx.nr; i++) {
 931                 if (!ctx.info[i].expired)
 932                         pack_name_concat_len += strlen(ctx.info[i].pack_name) + 1;
 933         }
 934
 935         /* Check that the preferred pack wasn't expired (if given). */
 936         if (preferred_pack_name) {
 937                 struct pack_info *preferred = bsearch(preferred_pack_name,
 938                                                       ctx.info, ctx.nr,
 939                                                       sizeof(*ctx.info),
 940                                                       idx_or_pack_name_cmp);
 941
 942                 if (!preferred)
 943                         warning(_("unknown preferred pack: '%s'"),
 944                                 preferred_pack_name);
 945                 else {
 946                         uint32_t perm = ctx.pack_perm[preferred->orig_pack_int_id];
 947                         if (perm == PACK_EXPIRED)
 948                                 warning(_("preferred pack '%s' is expired"),
 949                                         preferred_pack_name);
 950                 }
 951         }
 952
 953         if (pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
 954                 pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
 955                                         (pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
 956
 957         hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
 958         f = hashfd(get_lock_file_fd(&lk), get_lock_file_path(&lk));
 959         FREE_AND_NULL(midx_name);
 960
 961         if (ctx.m)
 962                 close_midx(ctx.m);
 963
 964         if (ctx.nr - dropped_packs == 0) {
 965                 error(_("no pack files to index."));
 966                 result = 1;
 967                 goto cleanup;
 968         }
 969
 970         cf = init_chunkfile(f);
 971
 972         add_chunk(cf, MIDX_CHUNKID_PACKNAMES, pack_name_concat_len,
 973                   write_midx_pack_names);
 974         add_chunk(cf, MIDX_CHUNKID_OIDFANOUT, MIDX_CHUNK_FANOUT_SIZE,
 975                   write_midx_oid_fanout);
 976         add_chunk(cf, MIDX_CHUNKID_OIDLOOKUP,
 977                   (size_t)ctx.entries_nr * the_hash_algo->rawsz,
 978                   write_midx_oid_lookup);
 979         add_chunk(cf, MIDX_CHUNKID_OBJECTOFFSETS,
 980                   (size_t)ctx.entries_nr * MIDX_CHUNK_OFFSET_WIDTH,
 981                   write_midx_object_offsets);
 982
 983         if (ctx.large_offsets_needed)
 984                 add_chunk(cf, MIDX_CHUNKID_LARGEOFFSETS,
 985                         (size_t)ctx.num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH,
 986                         write_midx_large_offsets);
 987
 988         write_midx_header(f, get_num_chunks(cf), ctx.nr - dropped_packs);
 989         write_chunkfile(cf, &ctx);
 990
 991         finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
 992         free_chunkfile(cf);
 993         commit_lock_file(&lk);
 994
 995 cleanup:
 996         for (i = 0; i < ctx.nr; i++) {
 997                 if (ctx.info[i].p) {
 998                         close_pack(ctx.info[i].p);
 999                         free(ctx.info[i].p);
1000                 }
1001                 free(ctx.info[i].pack_name);
1002         }
1003
1004         free(ctx.info);
1005         free(ctx.entries);
1006         free(ctx.pack_perm);
1007         free(midx_name);
1008         return result;
1009 }
1010
1011 int write_midx_file(const char *object_dir,
1012                     const char *preferred_pack_name,
1013                     unsigned flags)
1014 {
1015         return write_midx_internal(object_dir, NULL, NULL, preferred_pack_name,
1016                                    flags);
1017 }
1018
1019 void clear_midx_file(struct repository *r)
1020 {
1021         char *midx = get_midx_filename(r->objects->odb->path);
1022
1023         if (r->objects && r->objects->multi_pack_index) {
1024                 close_midx(r->objects->multi_pack_index);
1025                 r->objects->multi_pack_index = NULL;
1026         }
1027
1028         if (remove_path(midx))
1029                 die(_("failed to clear multi-pack-index at %s"), midx);
1030
1031         free(midx);
1032 }
1033
1034 static int verify_midx_error;
1035
1036 static void midx_report(const char *fmt, ...)
1037 {
1038         va_list ap;
1039         verify_midx_error = 1;
1040         va_start(ap, fmt);
1041         vfprintf(stderr, fmt, ap);
1042         fprintf(stderr, "\n");
1043         va_end(ap);
1044 }
1045
1046 struct pair_pos_vs_id
1047 {
1048         uint32_t pos;
1049         uint32_t pack_int_id;
1050 };
1051
1052 static int compare_pair_pos_vs_id(const void *_a, const void *_b)
1053 {
1054         struct pair_pos_vs_id *a = (struct pair_pos_vs_id *)_a;
1055         struct pair_pos_vs_id *b = (struct pair_pos_vs_id *)_b;
1056
1057         return b->pack_int_id - a->pack_int_id;
1058 }
1059
1060 /*
1061  * Limit calls to display_progress() for performance reasons.
1062  * The interval here was arbitrarily chosen.
1063  */
1064 #define SPARSE_PROGRESS_INTERVAL (1 << 12)
1065 #define midx_display_sparse_progress(progress, n) \
1066         do { \
1067                 uint64_t _n = (n); \
1068                 if ((_n & (SPARSE_PROGRESS_INTERVAL - 1)) == 0) \
1069                         display_progress(progress, _n); \
1070         } while (0)
1071
1072 int verify_midx_file(struct repository *r, const char *object_dir, unsigned flags)
1073 {
1074         struct pair_pos_vs_id *pairs = NULL;
1075         uint32_t i;
1076         struct progress *progress = NULL;
1077         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
1078         verify_midx_error = 0;
1079
1080         if (!m) {
1081                 int result = 0;
1082                 struct stat sb;
1083                 char *filename = get_midx_filename(object_dir);
1084                 if (!stat(filename, &sb)) {
1085                         error(_("multi-pack-index file exists, but failed to parse"));
1086                         result = 1;
1087                 }
1088                 free(filename);
1089                 return result;
1090         }
1091
1092         if (flags & MIDX_PROGRESS)
1093                 progress = start_delayed_progress(_("Looking for referenced packfiles"),
1094                                           m->num_packs);
1095         for (i = 0; i < m->num_packs; i++) {
1096                 if (prepare_midx_pack(r, m, i))
1097                         midx_report("failed to load pack in position %d", i);
1098
1099                 display_progress(progress, i + 1);
1100         }
1101         stop_progress(&progress);
1102
1103         for (i = 0; i < 255; i++) {
1104                 uint32_t oid_fanout1 = ntohl(m->chunk_oid_fanout[i]);
1105                 uint32_t oid_fanout2 = ntohl(m->chunk_oid_fanout[i + 1]);
1106
1107                 if (oid_fanout1 > oid_fanout2)
1108                         midx_report(_("oid fanout out of order: fanout[%d] = %"PRIx32" > %"PRIx32" = fanout[%d]"),
1109                                     i, oid_fanout1, oid_fanout2, i + 1);
1110         }
1111
1112         if (m->num_objects == 0) {
1113                 midx_report(_("the midx contains no oid"));
1114                 /*
1115                  * Remaining tests assume that we have objects, so we can
1116                  * return here.
1117                  */
1118                 return verify_midx_error;
1119         }
1120
1121         if (flags & MIDX_PROGRESS)
1122                 progress = start_sparse_progress(_("Verifying OID order in multi-pack-index"),
1123                                                  m->num_objects - 1);
1124         for (i = 0; i < m->num_objects - 1; i++) {
1125                 struct object_id oid1, oid2;
1126
1127                 nth_midxed_object_oid(&oid1, m, i);
1128                 nth_midxed_object_oid(&oid2, m, i + 1);
1129
1130                 if (oidcmp(&oid1, &oid2) >= 0)
1131                         midx_report(_("oid lookup out of order: oid[%d] = %s >= %s = oid[%d]"),
1132                                     i, oid_to_hex(&oid1), oid_to_hex(&oid2), i + 1);
1133
1134                 midx_display_sparse_progress(progress, i + 1);
1135         }
1136         stop_progress(&progress);
1137
1138         /*
1139          * Create an array mapping each object to its packfile id.  Sort it
1140          * to group the objects by packfile.  Use this permutation to visit
1141          * each of the objects and only require 1 packfile to be open at a
1142          * time.
1143          */
1144         ALLOC_ARRAY(pairs, m->num_objects);
1145         for (i = 0; i < m->num_objects; i++) {
1146                 pairs[i].pos = i;
1147                 pairs[i].pack_int_id = nth_midxed_pack_int_id(m, i);
1148         }
1149
1150         if (flags & MIDX_PROGRESS)
1151                 progress = start_sparse_progress(_("Sorting objects by packfile"),
1152                                                  m->num_objects);
1153         display_progress(progress, 0); /* TODO: Measure QSORT() progress */
1154         QSORT(pairs, m->num_objects, compare_pair_pos_vs_id);
1155         stop_progress(&progress);
1156
1157         if (flags & MIDX_PROGRESS)
1158                 progress = start_sparse_progress(_("Verifying object offsets"), m->num_objects);
1159         for (i = 0; i < m->num_objects; i++) {
1160                 struct object_id oid;
1161                 struct pack_entry e;
1162                 off_t m_offset, p_offset;
1163
1164                 if (i > 0 && pairs[i-1].pack_int_id != pairs[i].pack_int_id &&
1165                     m->packs[pairs[i-1].pack_int_id])
1166                 {
1167                         close_pack_fd(m->packs[pairs[i-1].pack_int_id]);
1168                         close_pack_index(m->packs[pairs[i-1].pack_int_id]);
1169                 }
1170
1171                 nth_midxed_object_oid(&oid, m, pairs[i].pos);
1172
1173                 if (!fill_midx_entry(r, &oid, &e, m)) {
1174                         midx_report(_("failed to load pack entry for oid[%d] = %s"),
1175                                     pairs[i].pos, oid_to_hex(&oid));
1176                         continue;
1177                 }
1178
1179                 if (open_pack_index(e.p)) {
1180                         midx_report(_("failed to load pack-index for packfile %s"),
1181                                     e.p->pack_name);
1182                         break;
1183                 }
1184
1185                 m_offset = e.offset;
1186                 p_offset = find_pack_entry_one(oid.hash, e.p);
1187
1188                 if (m_offset != p_offset)
1189                         midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
1190                                     pairs[i].pos, oid_to_hex(&oid), m_offset, p_offset);
1191
1192                 midx_display_sparse_progress(progress, i + 1);
1193         }
1194         stop_progress(&progress);
1195
1196         free(pairs);
1197
1198         return verify_midx_error;
1199 }
1200
1201 int expire_midx_packs(struct repository *r, const char *object_dir, unsigned flags)
1202 {
1203         uint32_t i, *count, result = 0;
1204         struct string_list packs_to_drop = STRING_LIST_INIT_DUP;
1205         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
1206         struct progress *progress = NULL;
1207
1208         if (!m)
1209                 return 0;
1210
1211         count = xcalloc(m->num_packs, sizeof(uint32_t));
1212
1213         if (flags & MIDX_PROGRESS)
1214                 progress = start_delayed_progress(_("Counting referenced objects"),
1215                                           m->num_objects);
1216         for (i = 0; i < m->num_objects; i++) {
1217                 int pack_int_id = nth_midxed_pack_int_id(m, i);
1218                 count[pack_int_id]++;
1219                 display_progress(progress, i + 1);
1220         }
1221         stop_progress(&progress);
1222
1223         if (flags & MIDX_PROGRESS)
1224                 progress = start_delayed_progress(_("Finding and deleting unreferenced packfiles"),
1225                                           m->num_packs);
1226         for (i = 0; i < m->num_packs; i++) {
1227                 char *pack_name;
1228                 display_progress(progress, i + 1);
1229
1230                 if (count[i])
1231                         continue;
1232
1233                 if (prepare_midx_pack(r, m, i))
1234                         continue;
1235
1236                 if (m->packs[i]->pack_keep)
1237                         continue;
1238
1239                 pack_name = xstrdup(m->packs[i]->pack_name);
1240                 close_pack(m->packs[i]);
1241
1242                 string_list_insert(&packs_to_drop, m->pack_names[i]);
1243                 unlink_pack_path(pack_name, 0);
1244                 free(pack_name);
1245         }
1246         stop_progress(&progress);
1247
1248         free(count);
1249
1250         if (packs_to_drop.nr)
1251                 result = write_midx_internal(object_dir, m, &packs_to_drop, NULL, flags);
1252
1253         string_list_clear(&packs_to_drop, 0);
1254         return result;
1255 }
1256
1257 struct repack_info {
1258         timestamp_t mtime;
1259         uint32_t referenced_objects;
1260         uint32_t pack_int_id;
1261 };
1262
1263 static int compare_by_mtime(const void *a_, const void *b_)
1264 {
1265         const struct repack_info *a, *b;
1266
1267         a = (const struct repack_info *)a_;
1268         b = (const struct repack_info *)b_;
1269
1270         if (a->mtime < b->mtime)
1271                 return -1;
1272         if (a->mtime > b->mtime)
1273                 return 1;
1274         return 0;
1275 }
1276
1277 static int fill_included_packs_all(struct repository *r,
1278                                    struct multi_pack_index *m,
1279                                    unsigned char *include_pack)
1280 {
1281         uint32_t i, count = 0;
1282         int pack_kept_objects = 0;
1283
1284         repo_config_get_bool(r, "repack.packkeptobjects", &pack_kept_objects);
1285
1286         for (i = 0; i < m->num_packs; i++) {
1287                 if (prepare_midx_pack(r, m, i))
1288                         continue;
1289                 if (!pack_kept_objects && m->packs[i]->pack_keep)
1290                         continue;
1291
1292                 include_pack[i] = 1;
1293                 count++;
1294         }
1295
1296         return count < 2;
1297 }
1298
1299 static int fill_included_packs_batch(struct repository *r,
1300                                      struct multi_pack_index *m,
1301                                      unsigned char *include_pack,
1302                                      size_t batch_size)
1303 {
1304         uint32_t i, packs_to_repack;
1305         size_t total_size;
1306         struct repack_info *pack_info = xcalloc(m->num_packs, sizeof(struct repack_info));
1307         int pack_kept_objects = 0;
1308
1309         repo_config_get_bool(r, "repack.packkeptobjects", &pack_kept_objects);
1310
1311         for (i = 0; i < m->num_packs; i++) {
1312                 pack_info[i].pack_int_id = i;
1313
1314                 if (prepare_midx_pack(r, m, i))
1315                         continue;
1316
1317                 pack_info[i].mtime = m->packs[i]->mtime;
1318         }
1319
1320         for (i = 0; batch_size && i < m->num_objects; i++) {
1321                 uint32_t pack_int_id = nth_midxed_pack_int_id(m, i);
1322                 pack_info[pack_int_id].referenced_objects++;
1323         }
1324
1325         QSORT(pack_info, m->num_packs, compare_by_mtime);
1326
1327         total_size = 0;
1328         packs_to_repack = 0;
1329         for (i = 0; total_size < batch_size && i < m->num_packs; i++) {
1330                 int pack_int_id = pack_info[i].pack_int_id;
1331                 struct packed_git *p = m->packs[pack_int_id];
1332                 size_t expected_size;
1333
1334                 if (!p)
1335                         continue;
1336                 if (!pack_kept_objects && p->pack_keep)
1337                         continue;
1338                 if (open_pack_index(p) || !p->num_objects)
1339                         continue;
1340
1341                 expected_size = (size_t)(p->pack_size
1342                                          * pack_info[i].referenced_objects);
1343                 expected_size /= p->num_objects;
1344
1345                 if (expected_size >= batch_size)
1346                         continue;
1347
1348                 packs_to_repack++;
1349                 total_size += expected_size;
1350                 include_pack[pack_int_id] = 1;
1351         }
1352
1353         free(pack_info);
1354
1355         if (packs_to_repack < 2)
1356                 return 1;
1357
1358         return 0;
1359 }
1360
1361 int midx_repack(struct repository *r, const char *object_dir, size_t batch_size, unsigned flags)
1362 {
1363         int result = 0;
1364         uint32_t i;
1365         unsigned char *include_pack;
1366         struct child_process cmd = CHILD_PROCESS_INIT;
1367         FILE *cmd_in;
1368         struct strbuf base_name = STRBUF_INIT;
1369         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
1370
1371         /*
1372          * When updating the default for these configuration
1373          * variables in builtin/repack.c, these must be adjusted
1374          * to match.
1375          */
1376         int delta_base_offset = 1;
1377         int use_delta_islands = 0;
1378
1379         if (!m)
1380                 return 0;
1381
1382         include_pack = xcalloc(m->num_packs, sizeof(unsigned char));
1383
1384         if (batch_size) {
1385                 if (fill_included_packs_batch(r, m, include_pack, batch_size))
1386                         goto cleanup;
1387         } else if (fill_included_packs_all(r, m, include_pack))
1388                 goto cleanup;
1389
1390         repo_config_get_bool(r, "repack.usedeltabaseoffset", &delta_base_offset);
1391         repo_config_get_bool(r, "repack.usedeltaislands", &use_delta_islands);
1392
1393         strvec_push(&cmd.args, "pack-objects");
1394
1395         strbuf_addstr(&base_name, object_dir);
1396         strbuf_addstr(&base_name, "/pack/pack");
1397         strvec_push(&cmd.args, base_name.buf);
1398
1399         if (delta_base_offset)
1400                 strvec_push(&cmd.args, "--delta-base-offset");
1401         if (use_delta_islands)
1402                 strvec_push(&cmd.args, "--delta-islands");
1403
1404         if (flags & MIDX_PROGRESS)
1405                 strvec_push(&cmd.args, "--progress");
1406         else
1407                 strvec_push(&cmd.args, "-q");
1408
1409         strbuf_release(&base_name);
1410
1411         cmd.git_cmd = 1;
1412         cmd.in = cmd.out = -1;
1413
1414         if (start_command(&cmd)) {
1415                 error(_("could not start pack-objects"));
1416                 result = 1;
1417                 goto cleanup;
1418         }
1419
1420         cmd_in = xfdopen(cmd.in, "w");
1421
1422         for (i = 0; i < m->num_objects; i++) {
1423                 struct object_id oid;
1424                 uint32_t pack_int_id = nth_midxed_pack_int_id(m, i);
1425
1426                 if (!include_pack[pack_int_id])
1427                         continue;
1428
1429                 nth_midxed_object_oid(&oid, m, i);
1430                 fprintf(cmd_in, "%s\n", oid_to_hex(&oid));
1431         }
1432         fclose(cmd_in);
1433
1434         if (finish_command(&cmd)) {
1435                 error(_("could not finish pack-objects"));
1436                 result = 1;
1437                 goto cleanup;
1438         }
1439
1440         result = write_midx_internal(object_dir, m, NULL, NULL, flags);
1441         m = NULL;
1442
1443 cleanup:
1444         if (m)
1445                 close_midx(m);
1446         free(include_pack);
1447         return result;
1448 }