git.oblomov.eu Git - git/blob - pack-bitmap.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "tag.h"
   4 #include "diff.h"
   5 #include "revision.h"
   6 #include "progress.h"
   7 #include "list-objects.h"
   8 #include "pack.h"
   9 #include "pack-bitmap.h"
  10 #include "pack-revindex.h"
  11 #include "pack-objects.h"
  12 #include "packfile.h"
  13 #include "repository.h"
  14 #include "object-store.h"
  15 #include "list-objects-filter-options.h"
  16
  17 /*
  18  * An entry on the bitmap index, representing the bitmap for a given
  19  * commit.
  20  */
  21 struct stored_bitmap {
  22         struct object_id oid;
  23         struct ewah_bitmap *root;
  24         struct stored_bitmap *xor;
  25         int flags;
  26 };
  27
  28 /*
  29  * The active bitmap index for a repository. By design, repositories only have
  30  * a single bitmap index available (the index for the biggest packfile in
  31  * the repository), since bitmap indexes need full closure.
  32  *
  33  * If there is more than one bitmap index available (e.g. because of alternates),
  34  * the active bitmap index is the largest one.
  35  */
  36 struct bitmap_index {
  37         /* Packfile to which this bitmap index belongs to */
  38         struct packed_git *pack;
  39
  40         /*
  41          * Mark the first `reuse_objects` in the packfile as reused:
  42          * they will be sent as-is without using them for repacking
  43          * calculations
  44          */
  45         uint32_t reuse_objects;
  46
  47         /* mmapped buffer of the whole bitmap index */
  48         unsigned char *map;
  49         size_t map_size; /* size of the mmaped buffer */
  50         size_t map_pos; /* current position when loading the index */
  51
  52         /*
  53          * Type indexes.
  54          *
  55          * Each bitmap marks which objects in the packfile  are of the given
  56          * type. This provides type information when yielding the objects from
  57          * the packfile during a walk, which allows for better delta bases.
  58          */
  59         struct ewah_bitmap *commits;
  60         struct ewah_bitmap *trees;
  61         struct ewah_bitmap *blobs;
  62         struct ewah_bitmap *tags;
  63
  64         /* Map from object ID -> `stored_bitmap` for all the bitmapped commits */
  65         kh_oid_map_t *bitmaps;
  66
  67         /* Number of bitmapped commits */
  68         uint32_t entry_count;
  69
  70         /* If not NULL, this is a name-hash cache pointing into map. */
  71         uint32_t *hashes;
  72
  73         /*
  74          * Extended index.
  75          *
  76          * When trying to perform bitmap operations with objects that are not
  77          * packed in `pack`, these objects are added to this "fake index" and
  78          * are assumed to appear at the end of the packfile for all operations
  79          */
  80         struct eindex {
  81                 struct object **objects;
  82                 uint32_t *hashes;
  83                 uint32_t count, alloc;
  84                 kh_oid_pos_t *positions;
  85         } ext_index;
  86
  87         /* Bitmap result of the last performed walk */
  88         struct bitmap *result;
  89
  90         /* "have" bitmap from the last performed walk */
  91         struct bitmap *haves;
  92
  93         /* Version of the bitmap index */
  94         unsigned int version;
  95 };
  96
  97 static struct ewah_bitmap *lookup_stored_bitmap(struct stored_bitmap *st)
  98 {
  99         struct ewah_bitmap *parent;
 100         struct ewah_bitmap *composed;
 101
 102         if (st->xor == NULL)
 103                 return st->root;
 104
 105         composed = ewah_pool_new();
 106         parent = lookup_stored_bitmap(st->xor);
 107         ewah_xor(st->root, parent, composed);
 108
 109         ewah_pool_free(st->root);
 110         st->root = composed;
 111         st->xor = NULL;
 112
 113         return composed;
 114 }
 115
 116 /*
 117  * Read a bitmap from the current read position on the mmaped
 118  * index, and increase the read position accordingly
 119  */
 120 static struct ewah_bitmap *read_bitmap_1(struct bitmap_index *index)
 121 {
 122         struct ewah_bitmap *b = ewah_pool_new();
 123
 124         ssize_t bitmap_size = ewah_read_mmap(b,
 125                 index->map + index->map_pos,
 126                 index->map_size - index->map_pos);
 127
 128         if (bitmap_size < 0) {
 129                 error("Failed to load bitmap index (corrupted?)");
 130                 ewah_pool_free(b);
 131                 return NULL;
 132         }
 133
 134         index->map_pos += bitmap_size;
 135         return b;
 136 }
 137
 138 static int load_bitmap_header(struct bitmap_index *index)
 139 {
 140         struct bitmap_disk_header *header = (void *)index->map;
 141
 142         if (index->map_size < sizeof(*header) + the_hash_algo->rawsz)
 143                 return error("Corrupted bitmap index (missing header data)");
 144
 145         if (memcmp(header->magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE)) != 0)
 146                 return error("Corrupted bitmap index file (wrong header)");
 147
 148         index->version = ntohs(header->version);
 149         if (index->version != 1)
 150                 return error("Unsupported version for bitmap index file (%d)", index->version);
 151
 152         /* Parse known bitmap format options */
 153         {
 154                 uint32_t flags = ntohs(header->options);
 155
 156                 if ((flags & BITMAP_OPT_FULL_DAG) == 0)
 157                         return error("Unsupported options for bitmap index file "
 158                                 "(Git requires BITMAP_OPT_FULL_DAG)");
 159
 160                 if (flags & BITMAP_OPT_HASH_CACHE) {
 161                         unsigned char *end = index->map + index->map_size - the_hash_algo->rawsz;
 162                         index->hashes = ((uint32_t *)end) - index->pack->num_objects;
 163                 }
 164         }
 165
 166         index->entry_count = ntohl(header->entry_count);
 167         index->map_pos += sizeof(*header) - GIT_MAX_RAWSZ + the_hash_algo->rawsz;
 168         return 0;
 169 }
 170
 171 static struct stored_bitmap *store_bitmap(struct bitmap_index *index,
 172                                           struct ewah_bitmap *root,
 173                                           const struct object_id *oid,
 174                                           struct stored_bitmap *xor_with,
 175                                           int flags)
 176 {
 177         struct stored_bitmap *stored;
 178         khiter_t hash_pos;
 179         int ret;
 180
 181         stored = xmalloc(sizeof(struct stored_bitmap));
 182         stored->root = root;
 183         stored->xor = xor_with;
 184         stored->flags = flags;
 185         oidcpy(&stored->oid, oid);
 186
 187         hash_pos = kh_put_oid_map(index->bitmaps, stored->oid, &ret);
 188
 189         /* a 0 return code means the insertion succeeded with no changes,
 190          * because the SHA1 already existed on the map. this is bad, there
 191          * shouldn't be duplicated commits in the index */
 192         if (ret == 0) {
 193                 error("Duplicate entry in bitmap index: %s", oid_to_hex(oid));
 194                 return NULL;
 195         }
 196
 197         kh_value(index->bitmaps, hash_pos) = stored;
 198         return stored;
 199 }
 200
 201 static inline uint32_t read_be32(const unsigned char *buffer, size_t *pos)
 202 {
 203         uint32_t result = get_be32(buffer + *pos);
 204         (*pos) += sizeof(result);
 205         return result;
 206 }
 207
 208 static inline uint8_t read_u8(const unsigned char *buffer, size_t *pos)
 209 {
 210         return buffer[(*pos)++];
 211 }
 212
 213 #define MAX_XOR_OFFSET 160
 214
 215 static int load_bitmap_entries_v1(struct bitmap_index *index)
 216 {
 217         uint32_t i;
 218         struct stored_bitmap *recent_bitmaps[MAX_XOR_OFFSET] = { NULL };
 219
 220         for (i = 0; i < index->entry_count; ++i) {
 221                 int xor_offset, flags;
 222                 struct ewah_bitmap *bitmap = NULL;
 223                 struct stored_bitmap *xor_bitmap = NULL;
 224                 uint32_t commit_idx_pos;
 225                 struct object_id oid;
 226
 227                 commit_idx_pos = read_be32(index->map, &index->map_pos);
 228                 xor_offset = read_u8(index->map, &index->map_pos);
 229                 flags = read_u8(index->map, &index->map_pos);
 230
 231                 nth_packed_object_id(&oid, index->pack, commit_idx_pos);
 232
 233                 bitmap = read_bitmap_1(index);
 234                 if (!bitmap)
 235                         return -1;
 236
 237                 if (xor_offset > MAX_XOR_OFFSET || xor_offset > i)
 238                         return error("Corrupted bitmap pack index");
 239
 240                 if (xor_offset > 0) {
 241                         xor_bitmap = recent_bitmaps[(i - xor_offset) % MAX_XOR_OFFSET];
 242
 243                         if (xor_bitmap == NULL)
 244                                 return error("Invalid XOR offset in bitmap pack index");
 245                 }
 246
 247                 recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
 248                         index, bitmap, &oid, xor_bitmap, flags);
 249         }
 250
 251         return 0;
 252 }
 253
 254 static char *pack_bitmap_filename(struct packed_git *p)
 255 {
 256         size_t len;
 257
 258         if (!strip_suffix(p->pack_name, ".pack", &len))
 259                 BUG("pack_name does not end in .pack");
 260         return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
 261 }
 262
 263 static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git *packfile)
 264 {
 265         int fd;
 266         struct stat st;
 267         char *idx_name;
 268
 269         if (open_pack_index(packfile))
 270                 return -1;
 271
 272         idx_name = pack_bitmap_filename(packfile);
 273         fd = git_open(idx_name);
 274         free(idx_name);
 275
 276         if (fd < 0)
 277                 return -1;
 278
 279         if (fstat(fd, &st)) {
 280                 close(fd);
 281                 return -1;
 282         }
 283
 284         if (bitmap_git->pack) {
 285                 warning("ignoring extra bitmap file: %s", packfile->pack_name);
 286                 close(fd);
 287                 return -1;
 288         }
 289
 290         bitmap_git->pack = packfile;
 291         bitmap_git->map_size = xsize_t(st.st_size);
 292         bitmap_git->map = xmmap(NULL, bitmap_git->map_size, PROT_READ, MAP_PRIVATE, fd, 0);
 293         bitmap_git->map_pos = 0;
 294         close(fd);
 295
 296         if (load_bitmap_header(bitmap_git) < 0) {
 297                 munmap(bitmap_git->map, bitmap_git->map_size);
 298                 bitmap_git->map = NULL;
 299                 bitmap_git->map_size = 0;
 300                 return -1;
 301         }
 302
 303         return 0;
 304 }
 305
 306 static int load_pack_bitmap(struct bitmap_index *bitmap_git)
 307 {
 308         assert(bitmap_git->map);
 309
 310         bitmap_git->bitmaps = kh_init_oid_map();
 311         bitmap_git->ext_index.positions = kh_init_oid_pos();
 312         if (load_pack_revindex(bitmap_git->pack))
 313                 goto failed;
 314
 315         if (!(bitmap_git->commits = read_bitmap_1(bitmap_git)) ||
 316                 !(bitmap_git->trees = read_bitmap_1(bitmap_git)) ||
 317                 !(bitmap_git->blobs = read_bitmap_1(bitmap_git)) ||
 318                 !(bitmap_git->tags = read_bitmap_1(bitmap_git)))
 319                 goto failed;
 320
 321         if (load_bitmap_entries_v1(bitmap_git) < 0)
 322                 goto failed;
 323
 324         return 0;
 325
 326 failed:
 327         munmap(bitmap_git->map, bitmap_git->map_size);
 328         bitmap_git->map = NULL;
 329         bitmap_git->map_size = 0;
 330
 331         kh_destroy_oid_map(bitmap_git->bitmaps);
 332         bitmap_git->bitmaps = NULL;
 333
 334         kh_destroy_oid_pos(bitmap_git->ext_index.positions);
 335         bitmap_git->ext_index.positions = NULL;
 336
 337         return -1;
 338 }
 339
 340 static int open_pack_bitmap(struct repository *r,
 341                             struct bitmap_index *bitmap_git)
 342 {
 343         struct packed_git *p;
 344         int ret = -1;
 345
 346         assert(!bitmap_git->map);
 347
 348         for (p = get_all_packs(r); p; p = p->next) {
 349                 if (open_pack_bitmap_1(bitmap_git, p) == 0)
 350                         ret = 0;
 351         }
 352
 353         return ret;
 354 }
 355
 356 struct bitmap_index *prepare_bitmap_git(struct repository *r)
 357 {
 358         struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
 359
 360         if (!open_pack_bitmap(r, bitmap_git) && !load_pack_bitmap(bitmap_git))
 361                 return bitmap_git;
 362
 363         free_bitmap_index(bitmap_git);
 364         return NULL;
 365 }
 366
 367 struct include_data {
 368         struct bitmap_index *bitmap_git;
 369         struct bitmap *base;
 370         struct bitmap *seen;
 371 };
 372
 373 static inline int bitmap_position_extended(struct bitmap_index *bitmap_git,
 374                                            const struct object_id *oid)
 375 {
 376         kh_oid_pos_t *positions = bitmap_git->ext_index.positions;
 377         khiter_t pos = kh_get_oid_pos(positions, *oid);
 378
 379         if (pos < kh_end(positions)) {
 380                 int bitmap_pos = kh_value(positions, pos);
 381                 return bitmap_pos + bitmap_git->pack->num_objects;
 382         }
 383
 384         return -1;
 385 }
 386
 387 static inline int bitmap_position_packfile(struct bitmap_index *bitmap_git,
 388                                            const struct object_id *oid)
 389 {
 390         off_t offset = find_pack_entry_one(oid->hash, bitmap_git->pack);
 391         if (!offset)
 392                 return -1;
 393
 394         return find_revindex_position(bitmap_git->pack, offset);
 395 }
 396
 397 static int bitmap_position(struct bitmap_index *bitmap_git,
 398                            const struct object_id *oid)
 399 {
 400         int pos = bitmap_position_packfile(bitmap_git, oid);
 401         return (pos >= 0) ? pos : bitmap_position_extended(bitmap_git, oid);
 402 }
 403
 404 static int ext_index_add_object(struct bitmap_index *bitmap_git,
 405                                 struct object *object, const char *name)
 406 {
 407         struct eindex *eindex = &bitmap_git->ext_index;
 408
 409         khiter_t hash_pos;
 410         int hash_ret;
 411         int bitmap_pos;
 412
 413         hash_pos = kh_put_oid_pos(eindex->positions, object->oid, &hash_ret);
 414         if (hash_ret > 0) {
 415                 if (eindex->count >= eindex->alloc) {
 416                         eindex->alloc = (eindex->alloc + 16) * 3 / 2;
 417                         REALLOC_ARRAY(eindex->objects, eindex->alloc);
 418                         REALLOC_ARRAY(eindex->hashes, eindex->alloc);
 419                 }
 420
 421                 bitmap_pos = eindex->count;
 422                 eindex->objects[eindex->count] = object;
 423                 eindex->hashes[eindex->count] = pack_name_hash(name);
 424                 kh_value(eindex->positions, hash_pos) = bitmap_pos;
 425                 eindex->count++;
 426         } else {
 427                 bitmap_pos = kh_value(eindex->positions, hash_pos);
 428         }
 429
 430         return bitmap_pos + bitmap_git->pack->num_objects;
 431 }
 432
 433 struct bitmap_show_data {
 434         struct bitmap_index *bitmap_git;
 435         struct bitmap *base;
 436 };
 437
 438 static void show_object(struct object *object, const char *name, void *data_)
 439 {
 440         struct bitmap_show_data *data = data_;
 441         int bitmap_pos;
 442
 443         bitmap_pos = bitmap_position(data->bitmap_git, &object->oid);
 444
 445         if (bitmap_pos < 0)
 446                 bitmap_pos = ext_index_add_object(data->bitmap_git, object,
 447                                                   name);
 448
 449         bitmap_set(data->base, bitmap_pos);
 450 }
 451
 452 static void show_commit(struct commit *commit, void *data)
 453 {
 454 }
 455
 456 static int add_to_include_set(struct bitmap_index *bitmap_git,
 457                               struct include_data *data,
 458                               const struct object_id *oid,
 459                               int bitmap_pos)
 460 {
 461         khiter_t hash_pos;
 462
 463         if (data->seen && bitmap_get(data->seen, bitmap_pos))
 464                 return 0;
 465
 466         if (bitmap_get(data->base, bitmap_pos))
 467                 return 0;
 468
 469         hash_pos = kh_get_oid_map(bitmap_git->bitmaps, *oid);
 470         if (hash_pos < kh_end(bitmap_git->bitmaps)) {
 471                 struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, hash_pos);
 472                 bitmap_or_ewah(data->base, lookup_stored_bitmap(st));
 473                 return 0;
 474         }
 475
 476         bitmap_set(data->base, bitmap_pos);
 477         return 1;
 478 }
 479
 480 static int should_include(struct commit *commit, void *_data)
 481 {
 482         struct include_data *data = _data;
 483         int bitmap_pos;
 484
 485         bitmap_pos = bitmap_position(data->bitmap_git, &commit->object.oid);
 486         if (bitmap_pos < 0)
 487                 bitmap_pos = ext_index_add_object(data->bitmap_git,
 488                                                   (struct object *)commit,
 489                                                   NULL);
 490
 491         if (!add_to_include_set(data->bitmap_git, data, &commit->object.oid,
 492                                 bitmap_pos)) {
 493                 struct commit_list *parent = commit->parents;
 494
 495                 while (parent) {
 496                         parent->item->object.flags |= SEEN;
 497                         parent = parent->next;
 498                 }
 499
 500                 return 0;
 501         }
 502
 503         return 1;
 504 }
 505
 506 static struct bitmap *find_objects(struct bitmap_index *bitmap_git,
 507                                    struct rev_info *revs,
 508                                    struct object_list *roots,
 509                                    struct bitmap *seen,
 510                                    struct list_objects_filter_options *filter)
 511 {
 512         struct bitmap *base = NULL;
 513         int needs_walk = 0;
 514
 515         struct object_list *not_mapped = NULL;
 516
 517         /*
 518          * Go through all the roots for the walk. The ones that have bitmaps
 519          * on the bitmap index will be `or`ed together to form an initial
 520          * global reachability analysis.
 521          *
 522          * The ones without bitmaps in the index will be stored in the
 523          * `not_mapped_list` for further processing.
 524          */
 525         while (roots) {
 526                 struct object *object = roots->item;
 527                 roots = roots->next;
 528
 529                 if (object->type == OBJ_COMMIT) {
 530                         khiter_t pos = kh_get_oid_map(bitmap_git->bitmaps, object->oid);
 531
 532                         if (pos < kh_end(bitmap_git->bitmaps)) {
 533                                 struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, pos);
 534                                 struct ewah_bitmap *or_with = lookup_stored_bitmap(st);
 535
 536                                 if (base == NULL)
 537                                         base = ewah_to_bitmap(or_with);
 538                                 else
 539                                         bitmap_or_ewah(base, or_with);
 540
 541                                 object->flags |= SEEN;
 542                                 continue;
 543                         }
 544                 }
 545
 546                 object_list_insert(object, &not_mapped);
 547         }
 548
 549         /*
 550          * Best case scenario: We found bitmaps for all the roots,
 551          * so the resulting `or` bitmap has the full reachability analysis
 552          */
 553         if (not_mapped == NULL)
 554                 return base;
 555
 556         roots = not_mapped;
 557
 558         /*
 559          * Let's iterate through all the roots that don't have bitmaps to
 560          * check if we can determine them to be reachable from the existing
 561          * global bitmap.
 562          *
 563          * If we cannot find them in the existing global bitmap, we'll need
 564          * to push them to an actual walk and run it until we can confirm
 565          * they are reachable
 566          */
 567         while (roots) {
 568                 struct object *object = roots->item;
 569                 int pos;
 570
 571                 roots = roots->next;
 572                 pos = bitmap_position(bitmap_git, &object->oid);
 573
 574                 if (pos < 0 || base == NULL || !bitmap_get(base, pos)) {
 575                         object->flags &= ~UNINTERESTING;
 576                         add_pending_object(revs, object, "");
 577                         needs_walk = 1;
 578                 } else {
 579                         object->flags |= SEEN;
 580                 }
 581         }
 582
 583         if (needs_walk) {
 584                 struct include_data incdata;
 585                 struct bitmap_show_data show_data;
 586
 587                 if (base == NULL)
 588                         base = bitmap_new();
 589
 590                 incdata.bitmap_git = bitmap_git;
 591                 incdata.base = base;
 592                 incdata.seen = seen;
 593
 594                 revs->include_check = should_include;
 595                 revs->include_check_data = &incdata;
 596
 597                 if (prepare_revision_walk(revs))
 598                         die("revision walk setup failed");
 599
 600                 show_data.bitmap_git = bitmap_git;
 601                 show_data.base = base;
 602
 603                 traverse_commit_list_filtered(filter, revs,
 604                                               show_commit, show_object,
 605                                               &show_data, NULL);
 606         }
 607
 608         return base;
 609 }
 610
 611 static void show_extended_objects(struct bitmap_index *bitmap_git,
 612                                   struct rev_info *revs,
 613                                   show_reachable_fn show_reach)
 614 {
 615         struct bitmap *objects = bitmap_git->result;
 616         struct eindex *eindex = &bitmap_git->ext_index;
 617         uint32_t i;
 618
 619         for (i = 0; i < eindex->count; ++i) {
 620                 struct object *obj;
 621
 622                 if (!bitmap_get(objects, bitmap_git->pack->num_objects + i))
 623                         continue;
 624
 625                 obj = eindex->objects[i];
 626                 if ((obj->type == OBJ_BLOB && !revs->blob_objects) ||
 627                     (obj->type == OBJ_TREE && !revs->tree_objects) ||
 628                     (obj->type == OBJ_TAG && !revs->tag_objects))
 629                         continue;
 630
 631                 show_reach(&obj->oid, obj->type, 0, eindex->hashes[i], NULL, 0);
 632         }
 633 }
 634
 635 static void init_type_iterator(struct ewah_iterator *it,
 636                                struct bitmap_index *bitmap_git,
 637                                enum object_type type)
 638 {
 639         switch (type) {
 640         case OBJ_COMMIT:
 641                 ewah_iterator_init(it, bitmap_git->commits);
 642                 break;
 643
 644         case OBJ_TREE:
 645                 ewah_iterator_init(it, bitmap_git->trees);
 646                 break;
 647
 648         case OBJ_BLOB:
 649                 ewah_iterator_init(it, bitmap_git->blobs);
 650                 break;
 651
 652         case OBJ_TAG:
 653                 ewah_iterator_init(it, bitmap_git->tags);
 654                 break;
 655
 656         default:
 657                 BUG("object type %d not stored by bitmap type index", type);
 658                 break;
 659         }
 660 }
 661
 662 static void show_objects_for_type(
 663         struct bitmap_index *bitmap_git,
 664         enum object_type object_type,
 665         show_reachable_fn show_reach)
 666 {
 667         size_t i = 0;
 668         uint32_t offset;
 669
 670         struct ewah_iterator it;
 671         eword_t filter;
 672
 673         struct bitmap *objects = bitmap_git->result;
 674
 675         init_type_iterator(&it, bitmap_git, object_type);
 676
 677         for (i = 0; i < objects->word_alloc &&
 678                         ewah_iterator_next(&filter, &it); i++) {
 679                 eword_t word = objects->words[i] & filter;
 680                 size_t pos = (i * BITS_IN_EWORD);
 681
 682                 if (!word)
 683                         continue;
 684
 685                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
 686                         struct object_id oid;
 687                         struct revindex_entry *entry;
 688                         uint32_t hash = 0;
 689
 690                         if ((word >> offset) == 0)
 691                                 break;
 692
 693                         offset += ewah_bit_ctz64(word >> offset);
 694
 695                         entry = &bitmap_git->pack->revindex[pos + offset];
 696                         nth_packed_object_id(&oid, bitmap_git->pack, entry->nr);
 697
 698                         if (bitmap_git->hashes)
 699                                 hash = get_be32(bitmap_git->hashes + entry->nr);
 700
 701                         show_reach(&oid, object_type, 0, hash, bitmap_git->pack, entry->offset);
 702                 }
 703         }
 704 }
 705
 706 static int in_bitmapped_pack(struct bitmap_index *bitmap_git,
 707                              struct object_list *roots)
 708 {
 709         while (roots) {
 710                 struct object *object = roots->item;
 711                 roots = roots->next;
 712
 713                 if (find_pack_entry_one(object->oid.hash, bitmap_git->pack) > 0)
 714                         return 1;
 715         }
 716
 717         return 0;
 718 }
 719
 720 static struct bitmap *find_tip_objects(struct bitmap_index *bitmap_git,
 721                                        struct object_list *tip_objects,
 722                                        enum object_type type)
 723 {
 724         struct bitmap *result = bitmap_new();
 725         struct object_list *p;
 726
 727         for (p = tip_objects; p; p = p->next) {
 728                 int pos;
 729
 730                 if (p->item->type != type)
 731                         continue;
 732
 733                 pos = bitmap_position(bitmap_git, &p->item->oid);
 734                 if (pos < 0)
 735                         continue;
 736
 737                 bitmap_set(result, pos);
 738         }
 739
 740         return result;
 741 }
 742
 743 static void filter_bitmap_exclude_type(struct bitmap_index *bitmap_git,
 744                                        struct object_list *tip_objects,
 745                                        struct bitmap *to_filter,
 746                                        enum object_type type)
 747 {
 748         struct eindex *eindex = &bitmap_git->ext_index;
 749         struct bitmap *tips;
 750         struct ewah_iterator it;
 751         eword_t mask;
 752         uint32_t i;
 753
 754         if (type != OBJ_BLOB && type != OBJ_TREE)
 755                 BUG("filter_bitmap_exclude_type: unsupported type '%d'", type);
 756
 757         /*
 758          * The non-bitmap version of this filter never removes
 759          * objects which the other side specifically asked for,
 760          * so we must match that behavior.
 761          */
 762         tips = find_tip_objects(bitmap_git, tip_objects, type);
 763
 764         /*
 765          * We can use the blob type-bitmap to work in whole words
 766          * for the objects that are actually in the bitmapped packfile.
 767          */
 768         for (i = 0, init_type_iterator(&it, bitmap_git, type);
 769              i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
 770              i++) {
 771                 if (i < tips->word_alloc)
 772                         mask &= ~tips->words[i];
 773                 to_filter->words[i] &= ~mask;
 774         }
 775
 776         /*
 777          * Clear any blobs that weren't in the packfile (and so would not have
 778          * been caught by the loop above. We'll have to check them
 779          * individually.
 780          */
 781         for (i = 0; i < eindex->count; i++) {
 782                 uint32_t pos = i + bitmap_git->pack->num_objects;
 783                 if (eindex->objects[i]->type == type &&
 784                     bitmap_get(to_filter, pos) &&
 785                     !bitmap_get(tips, pos))
 786                         bitmap_unset(to_filter, pos);
 787         }
 788
 789         bitmap_free(tips);
 790 }
 791
 792 static void filter_bitmap_blob_none(struct bitmap_index *bitmap_git,
 793                                     struct object_list *tip_objects,
 794                                     struct bitmap *to_filter)
 795 {
 796         filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
 797                                    OBJ_BLOB);
 798 }
 799
 800 static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
 801                                      uint32_t pos)
 802 {
 803         struct packed_git *pack = bitmap_git->pack;
 804         unsigned long size;
 805         struct object_info oi = OBJECT_INFO_INIT;
 806
 807         oi.sizep = &size;
 808
 809         if (pos < pack->num_objects) {
 810                 struct revindex_entry *entry = &pack->revindex[pos];
 811                 if (packed_object_info(the_repository, pack,
 812                                        entry->offset, &oi) < 0) {
 813                         struct object_id oid;
 814                         nth_packed_object_id(&oid, pack, entry->nr);
 815                         die(_("unable to get size of %s"), oid_to_hex(&oid));
 816                 }
 817         } else {
 818                 struct eindex *eindex = &bitmap_git->ext_index;
 819                 struct object *obj = eindex->objects[pos - pack->num_objects];
 820                 if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
 821                         die(_("unable to get size of %s"), oid_to_hex(&obj->oid));
 822         }
 823
 824         return size;
 825 }
 826
 827 static void filter_bitmap_blob_limit(struct bitmap_index *bitmap_git,
 828                                      struct object_list *tip_objects,
 829                                      struct bitmap *to_filter,
 830                                      unsigned long limit)
 831 {
 832         struct eindex *eindex = &bitmap_git->ext_index;
 833         struct bitmap *tips;
 834         struct ewah_iterator it;
 835         eword_t mask;
 836         uint32_t i;
 837
 838         tips = find_tip_objects(bitmap_git, tip_objects, OBJ_BLOB);
 839
 840         for (i = 0, init_type_iterator(&it, bitmap_git, OBJ_BLOB);
 841              i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
 842              i++) {
 843                 eword_t word = to_filter->words[i] & mask;
 844                 unsigned offset;
 845
 846                 for (offset = 0; offset < BITS_IN_EWORD; offset++) {
 847                         uint32_t pos;
 848
 849                         if ((word >> offset) == 0)
 850                                 break;
 851                         offset += ewah_bit_ctz64(word >> offset);
 852                         pos = i * BITS_IN_EWORD + offset;
 853
 854                         if (!bitmap_get(tips, pos) &&
 855                             get_size_by_pos(bitmap_git, pos) >= limit)
 856                                 bitmap_unset(to_filter, pos);
 857                 }
 858         }
 859
 860         for (i = 0; i < eindex->count; i++) {
 861                 uint32_t pos = i + bitmap_git->pack->num_objects;
 862                 if (eindex->objects[i]->type == OBJ_BLOB &&
 863                     bitmap_get(to_filter, pos) &&
 864                     !bitmap_get(tips, pos) &&
 865                     get_size_by_pos(bitmap_git, pos) >= limit)
 866                         bitmap_unset(to_filter, pos);
 867         }
 868
 869         bitmap_free(tips);
 870 }
 871
 872 static void filter_bitmap_tree_depth(struct bitmap_index *bitmap_git,
 873                                      struct object_list *tip_objects,
 874                                      struct bitmap *to_filter,
 875                                      unsigned long limit)
 876 {
 877         if (limit)
 878                 BUG("filter_bitmap_tree_depth given non-zero limit");
 879
 880         filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
 881                                    OBJ_TREE);
 882         filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
 883                                    OBJ_BLOB);
 884 }
 885
 886 static int filter_bitmap(struct bitmap_index *bitmap_git,
 887                          struct object_list *tip_objects,
 888                          struct bitmap *to_filter,
 889                          struct list_objects_filter_options *filter)
 890 {
 891         if (!filter || filter->choice == LOFC_DISABLED)
 892                 return 0;
 893
 894         if (filter->choice == LOFC_BLOB_NONE) {
 895                 if (bitmap_git)
 896                         filter_bitmap_blob_none(bitmap_git, tip_objects,
 897                                                 to_filter);
 898                 return 0;
 899         }
 900
 901         if (filter->choice == LOFC_BLOB_LIMIT) {
 902                 if (bitmap_git)
 903                         filter_bitmap_blob_limit(bitmap_git, tip_objects,
 904                                                  to_filter,
 905                                                  filter->blob_limit_value);
 906                 return 0;
 907         }
 908
 909         if (filter->choice == LOFC_TREE_DEPTH &&
 910             filter->tree_exclude_depth == 0) {
 911                 if (bitmap_git)
 912                         filter_bitmap_tree_depth(bitmap_git, tip_objects,
 913                                                  to_filter,
 914                                                  filter->tree_exclude_depth);
 915                 return 0;
 916         }
 917
 918         /* filter choice not handled */
 919         return -1;
 920 }
 921
 922 static int can_filter_bitmap(struct list_objects_filter_options *filter)
 923 {
 924         return !filter_bitmap(NULL, NULL, NULL, filter);
 925 }
 926
 927 struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs,
 928                                          struct list_objects_filter_options *filter)
 929 {
 930         unsigned int i;
 931
 932         struct object_list *wants = NULL;
 933         struct object_list *haves = NULL;
 934
 935         struct bitmap *wants_bitmap = NULL;
 936         struct bitmap *haves_bitmap = NULL;
 937
 938         struct bitmap_index *bitmap_git;
 939
 940         /*
 941          * We can't do pathspec limiting with bitmaps, because we don't know
 942          * which commits are associated with which object changes (let alone
 943          * even which objects are associated with which paths).
 944          */
 945         if (revs->prune)
 946                 return NULL;
 947
 948         if (!can_filter_bitmap(filter))
 949                 return NULL;
 950
 951         /* try to open a bitmapped pack, but don't parse it yet
 952          * because we may not need to use it */
 953         bitmap_git = xcalloc(1, sizeof(*bitmap_git));
 954         if (open_pack_bitmap(revs->repo, bitmap_git) < 0)
 955                 goto cleanup;
 956
 957         for (i = 0; i < revs->pending.nr; ++i) {
 958                 struct object *object = revs->pending.objects[i].item;
 959
 960                 if (object->type == OBJ_NONE)
 961                         parse_object_or_die(&object->oid, NULL);
 962
 963                 while (object->type == OBJ_TAG) {
 964                         struct tag *tag = (struct tag *) object;
 965
 966                         if (object->flags & UNINTERESTING)
 967                                 object_list_insert(object, &haves);
 968                         else
 969                                 object_list_insert(object, &wants);
 970
 971                         object = parse_object_or_die(get_tagged_oid(tag), NULL);
 972                 }
 973
 974                 if (object->flags & UNINTERESTING)
 975                         object_list_insert(object, &haves);
 976                 else
 977                         object_list_insert(object, &wants);
 978         }
 979
 980         /*
 981          * if we have a HAVES list, but none of those haves is contained
 982          * in the packfile that has a bitmap, we don't have anything to
 983          * optimize here
 984          */
 985         if (haves && !in_bitmapped_pack(bitmap_git, haves))
 986                 goto cleanup;
 987
 988         /* if we don't want anything, we're done here */
 989         if (!wants)
 990                 goto cleanup;
 991
 992         /*
 993          * now we're going to use bitmaps, so load the actual bitmap entries
 994          * from disk. this is the point of no return; after this the rev_list
 995          * becomes invalidated and we must perform the revwalk through bitmaps
 996          */
 997         if (load_pack_bitmap(bitmap_git) < 0)
 998                 goto cleanup;
 999
1000         object_array_clear(&revs->pending);
1001
1002         if (haves) {
1003                 revs->ignore_missing_links = 1;
1004                 haves_bitmap = find_objects(bitmap_git, revs, haves, NULL,
1005                                             filter);
1006                 reset_revision_walk();
1007                 revs->ignore_missing_links = 0;
1008
1009                 if (haves_bitmap == NULL)
1010                         BUG("failed to perform bitmap walk");
1011         }
1012
1013         wants_bitmap = find_objects(bitmap_git, revs, wants, haves_bitmap,
1014                                     filter);
1015
1016         if (!wants_bitmap)
1017                 BUG("failed to perform bitmap walk");
1018
1019         if (haves_bitmap)
1020                 bitmap_and_not(wants_bitmap, haves_bitmap);
1021
1022         filter_bitmap(bitmap_git, wants, wants_bitmap, filter);
1023
1024         bitmap_git->result = wants_bitmap;
1025         bitmap_git->haves = haves_bitmap;
1026
1027         object_list_free(&wants);
1028         object_list_free(&haves);
1029
1030         return bitmap_git;
1031
1032 cleanup:
1033         free_bitmap_index(bitmap_git);
1034         object_list_free(&wants);
1035         object_list_free(&haves);
1036         return NULL;
1037 }
1038
1039 static void try_partial_reuse(struct bitmap_index *bitmap_git,
1040                               size_t pos,
1041                               struct bitmap *reuse,
1042                               struct pack_window **w_curs)
1043 {
1044         struct revindex_entry *revidx;
1045         off_t offset;
1046         enum object_type type;
1047         unsigned long size;
1048
1049         if (pos >= bitmap_git->pack->num_objects)
1050                 return; /* not actually in the pack */
1051
1052         revidx = &bitmap_git->pack->revindex[pos];
1053         offset = revidx->offset;
1054         type = unpack_object_header(bitmap_git->pack, w_curs, &offset, &size);
1055         if (type < 0)
1056                 return; /* broken packfile, punt */
1057
1058         if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA) {
1059                 off_t base_offset;
1060                 int base_pos;
1061
1062                 /*
1063                  * Find the position of the base object so we can look it up
1064                  * in our bitmaps. If we can't come up with an offset, or if
1065                  * that offset is not in the revidx, the pack is corrupt.
1066                  * There's nothing we can do, so just punt on this object,
1067                  * and the normal slow path will complain about it in
1068                  * more detail.
1069                  */
1070                 base_offset = get_delta_base(bitmap_git->pack, w_curs,
1071                                              &offset, type, revidx->offset);
1072                 if (!base_offset)
1073                         return;
1074                 base_pos = find_revindex_position(bitmap_git->pack, base_offset);
1075                 if (base_pos < 0)
1076                         return;
1077
1078                 /*
1079                  * We assume delta dependencies always point backwards. This
1080                  * lets us do a single pass, and is basically always true
1081                  * due to the way OFS_DELTAs work. You would not typically
1082                  * find REF_DELTA in a bitmapped pack, since we only bitmap
1083                  * packs we write fresh, and OFS_DELTA is the default). But
1084                  * let's double check to make sure the pack wasn't written with
1085                  * odd parameters.
1086                  */
1087                 if (base_pos >= pos)
1088                         return;
1089
1090                 /*
1091                  * And finally, if we're not sending the base as part of our
1092                  * reuse chunk, then don't send this object either. The base
1093                  * would come after us, along with other objects not
1094                  * necessarily in the pack, which means we'd need to convert
1095                  * to REF_DELTA on the fly. Better to just let the normal
1096                  * object_entry code path handle it.
1097                  */
1098                 if (!bitmap_get(reuse, base_pos))
1099                         return;
1100         }
1101
1102         /*
1103          * If we got here, then the object is OK to reuse. Mark it.
1104          */
1105         bitmap_set(reuse, pos);
1106 }
1107
1108 int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
1109                                        struct packed_git **packfile_out,
1110                                        uint32_t *entries,
1111                                        struct bitmap **reuse_out)
1112 {
1113         struct bitmap *result = bitmap_git->result;
1114         struct bitmap *reuse;
1115         struct pack_window *w_curs = NULL;
1116         size_t i = 0;
1117         uint32_t offset;
1118
1119         assert(result);
1120
1121         while (i < result->word_alloc && result->words[i] == (eword_t)~0)
1122                 i++;
1123
1124         /* Don't mark objects not in the packfile */
1125         if (i > bitmap_git->pack->num_objects / BITS_IN_EWORD)
1126                 i = bitmap_git->pack->num_objects / BITS_IN_EWORD;
1127
1128         reuse = bitmap_word_alloc(i);
1129         memset(reuse->words, 0xFF, i * sizeof(eword_t));
1130
1131         for (; i < result->word_alloc; ++i) {
1132                 eword_t word = result->words[i];
1133                 size_t pos = (i * BITS_IN_EWORD);
1134
1135                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
1136                         if ((word >> offset) == 0)
1137                                 break;
1138
1139                         offset += ewah_bit_ctz64(word >> offset);
1140                         try_partial_reuse(bitmap_git, pos + offset, reuse, &w_curs);
1141                 }
1142         }
1143
1144         unuse_pack(&w_curs);
1145
1146         *entries = bitmap_popcount(reuse);
1147         if (!*entries) {
1148                 bitmap_free(reuse);
1149                 return -1;
1150         }
1151
1152         /*
1153          * Drop any reused objects from the result, since they will not
1154          * need to be handled separately.
1155          */
1156         bitmap_and_not(result, reuse);
1157         *packfile_out = bitmap_git->pack;
1158         *reuse_out = reuse;
1159         return 0;
1160 }
1161
1162 int bitmap_walk_contains(struct bitmap_index *bitmap_git,
1163                          struct bitmap *bitmap, const struct object_id *oid)
1164 {
1165         int idx;
1166
1167         if (!bitmap)
1168                 return 0;
1169
1170         idx = bitmap_position(bitmap_git, oid);
1171         return idx >= 0 && bitmap_get(bitmap, idx);
1172 }
1173
1174 void traverse_bitmap_commit_list(struct bitmap_index *bitmap_git,
1175                                  struct rev_info *revs,
1176                                  show_reachable_fn show_reachable)
1177 {
1178         assert(bitmap_git->result);
1179
1180         show_objects_for_type(bitmap_git, OBJ_COMMIT, show_reachable);
1181         if (revs->tree_objects)
1182                 show_objects_for_type(bitmap_git, OBJ_TREE, show_reachable);
1183         if (revs->blob_objects)
1184                 show_objects_for_type(bitmap_git, OBJ_BLOB, show_reachable);
1185         if (revs->tag_objects)
1186                 show_objects_for_type(bitmap_git, OBJ_TAG, show_reachable);
1187
1188         show_extended_objects(bitmap_git, revs, show_reachable);
1189 }
1190
1191 static uint32_t count_object_type(struct bitmap_index *bitmap_git,
1192                                   enum object_type type)
1193 {
1194         struct bitmap *objects = bitmap_git->result;
1195         struct eindex *eindex = &bitmap_git->ext_index;
1196
1197         uint32_t i = 0, count = 0;
1198         struct ewah_iterator it;
1199         eword_t filter;
1200
1201         init_type_iterator(&it, bitmap_git, type);
1202
1203         while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
1204                 eword_t word = objects->words[i++] & filter;
1205                 count += ewah_bit_popcount64(word);
1206         }
1207
1208         for (i = 0; i < eindex->count; ++i) {
1209                 if (eindex->objects[i]->type == type &&
1210                         bitmap_get(objects, bitmap_git->pack->num_objects + i))
1211                         count++;
1212         }
1213
1214         return count;
1215 }
1216
1217 void count_bitmap_commit_list(struct bitmap_index *bitmap_git,
1218                               uint32_t *commits, uint32_t *trees,
1219                               uint32_t *blobs, uint32_t *tags)
1220 {
1221         assert(bitmap_git->result);
1222
1223         if (commits)
1224                 *commits = count_object_type(bitmap_git, OBJ_COMMIT);
1225
1226         if (trees)
1227                 *trees = count_object_type(bitmap_git, OBJ_TREE);
1228
1229         if (blobs)
1230                 *blobs = count_object_type(bitmap_git, OBJ_BLOB);
1231
1232         if (tags)
1233                 *tags = count_object_type(bitmap_git, OBJ_TAG);
1234 }
1235
1236 struct bitmap_test_data {
1237         struct bitmap_index *bitmap_git;
1238         struct bitmap *base;
1239         struct progress *prg;
1240         size_t seen;
1241 };
1242
1243 static void test_show_object(struct object *object, const char *name,
1244                              void *data)
1245 {
1246         struct bitmap_test_data *tdata = data;
1247         int bitmap_pos;
1248
1249         bitmap_pos = bitmap_position(tdata->bitmap_git, &object->oid);
1250         if (bitmap_pos < 0)
1251                 die("Object not in bitmap: %s\n", oid_to_hex(&object->oid));
1252
1253         bitmap_set(tdata->base, bitmap_pos);
1254         display_progress(tdata->prg, ++tdata->seen);
1255 }
1256
1257 static void test_show_commit(struct commit *commit, void *data)
1258 {
1259         struct bitmap_test_data *tdata = data;
1260         int bitmap_pos;
1261
1262         bitmap_pos = bitmap_position(tdata->bitmap_git,
1263                                      &commit->object.oid);
1264         if (bitmap_pos < 0)
1265                 die("Object not in bitmap: %s\n", oid_to_hex(&commit->object.oid));
1266
1267         bitmap_set(tdata->base, bitmap_pos);
1268         display_progress(tdata->prg, ++tdata->seen);
1269 }
1270
1271 void test_bitmap_walk(struct rev_info *revs)
1272 {
1273         struct object *root;
1274         struct bitmap *result = NULL;
1275         khiter_t pos;
1276         size_t result_popcnt;
1277         struct bitmap_test_data tdata;
1278         struct bitmap_index *bitmap_git;
1279
1280         if (!(bitmap_git = prepare_bitmap_git(revs->repo)))
1281                 die("failed to load bitmap indexes");
1282
1283         if (revs->pending.nr != 1)
1284                 die("you must specify exactly one commit to test");
1285
1286         fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
1287                 bitmap_git->version, bitmap_git->entry_count);
1288
1289         root = revs->pending.objects[0].item;
1290         pos = kh_get_oid_map(bitmap_git->bitmaps, root->oid);
1291
1292         if (pos < kh_end(bitmap_git->bitmaps)) {
1293                 struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, pos);
1294                 struct ewah_bitmap *bm = lookup_stored_bitmap(st);
1295
1296                 fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
1297                         oid_to_hex(&root->oid), (int)bm->bit_size, ewah_checksum(bm));
1298
1299                 result = ewah_to_bitmap(bm);
1300         }
1301
1302         if (result == NULL)
1303                 die("Commit %s doesn't have an indexed bitmap", oid_to_hex(&root->oid));
1304
1305         revs->tag_objects = 1;
1306         revs->tree_objects = 1;
1307         revs->blob_objects = 1;
1308
1309         result_popcnt = bitmap_popcount(result);
1310
1311         if (prepare_revision_walk(revs))
1312                 die("revision walk setup failed");
1313
1314         tdata.bitmap_git = bitmap_git;
1315         tdata.base = bitmap_new();
1316         tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
1317         tdata.seen = 0;
1318
1319         traverse_commit_list(revs, &test_show_commit, &test_show_object, &tdata);
1320
1321         stop_progress(&tdata.prg);
1322
1323         if (bitmap_equals(result, tdata.base))
1324                 fprintf(stderr, "OK!\n");
1325         else
1326                 fprintf(stderr, "Mismatch!\n");
1327
1328         free_bitmap_index(bitmap_git);
1329 }
1330
1331 static int rebuild_bitmap(uint32_t *reposition,
1332                           struct ewah_bitmap *source,
1333                           struct bitmap *dest)
1334 {
1335         uint32_t pos = 0;
1336         struct ewah_iterator it;
1337         eword_t word;
1338
1339         ewah_iterator_init(&it, source);
1340
1341         while (ewah_iterator_next(&word, &it)) {
1342                 uint32_t offset, bit_pos;
1343
1344                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
1345                         if ((word >> offset) == 0)
1346                                 break;
1347
1348                         offset += ewah_bit_ctz64(word >> offset);
1349
1350                         bit_pos = reposition[pos + offset];
1351                         if (bit_pos > 0)
1352                                 bitmap_set(dest, bit_pos - 1);
1353                         else /* can't reuse, we don't have the object */
1354                                 return -1;
1355                 }
1356
1357                 pos += BITS_IN_EWORD;
1358         }
1359         return 0;
1360 }
1361
1362 int rebuild_existing_bitmaps(struct bitmap_index *bitmap_git,
1363                              struct packing_data *mapping,
1364                              kh_oid_map_t *reused_bitmaps,
1365                              int show_progress)
1366 {
1367         uint32_t i, num_objects;
1368         uint32_t *reposition;
1369         struct bitmap *rebuild;
1370         struct stored_bitmap *stored;
1371         struct progress *progress = NULL;
1372
1373         khiter_t hash_pos;
1374         int hash_ret;
1375
1376         num_objects = bitmap_git->pack->num_objects;
1377         reposition = xcalloc(num_objects, sizeof(uint32_t));
1378
1379         for (i = 0; i < num_objects; ++i) {
1380                 struct object_id oid;
1381                 struct revindex_entry *entry;
1382                 struct object_entry *oe;
1383
1384                 entry = &bitmap_git->pack->revindex[i];
1385                 nth_packed_object_id(&oid, bitmap_git->pack, entry->nr);
1386                 oe = packlist_find(mapping, &oid);
1387
1388                 if (oe)
1389                         reposition[i] = oe_in_pack_pos(mapping, oe) + 1;
1390         }
1391
1392         rebuild = bitmap_new();
1393         i = 0;
1394
1395         if (show_progress)
1396                 progress = start_progress("Reusing bitmaps", 0);
1397
1398         kh_foreach_value(bitmap_git->bitmaps, stored, {
1399                 if (stored->flags & BITMAP_FLAG_REUSE) {
1400                         if (!rebuild_bitmap(reposition,
1401                                             lookup_stored_bitmap(stored),
1402                                             rebuild)) {
1403                                 hash_pos = kh_put_oid_map(reused_bitmaps,
1404                                                           stored->oid,
1405                                                           &hash_ret);
1406                                 kh_value(reused_bitmaps, hash_pos) =
1407                                         bitmap_to_ewah(rebuild);
1408                         }
1409                         bitmap_reset(rebuild);
1410                         display_progress(progress, ++i);
1411                 }
1412         });
1413
1414         stop_progress(&progress);
1415
1416         free(reposition);
1417         bitmap_free(rebuild);
1418         return 0;
1419 }
1420
1421 void free_bitmap_index(struct bitmap_index *b)
1422 {
1423         if (!b)
1424                 return;
1425
1426         if (b->map)
1427                 munmap(b->map, b->map_size);
1428         ewah_pool_free(b->commits);
1429         ewah_pool_free(b->trees);
1430         ewah_pool_free(b->blobs);
1431         ewah_pool_free(b->tags);
1432         kh_destroy_oid_map(b->bitmaps);
1433         free(b->ext_index.objects);
1434         free(b->ext_index.hashes);
1435         bitmap_free(b->result);
1436         bitmap_free(b->haves);
1437         free(b);
1438 }
1439
1440 int bitmap_has_oid_in_uninteresting(struct bitmap_index *bitmap_git,
1441                                     const struct object_id *oid)
1442 {
1443         return bitmap_git &&
1444                 bitmap_walk_contains(bitmap_git, bitmap_git->haves, oid);
1445 }