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         size_t header_size = sizeof(*header) - GIT_MAX_RAWSZ + the_hash_algo->rawsz;
 142
 143         if (index->map_size < header_size + the_hash_algo->rawsz)
 144                 return error("Corrupted bitmap index (too small)");
 145
 146         if (memcmp(header->magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE)) != 0)
 147                 return error("Corrupted bitmap index file (wrong header)");
 148
 149         index->version = ntohs(header->version);
 150         if (index->version != 1)
 151                 return error("Unsupported version for bitmap index file (%d)", index->version);
 152
 153         /* Parse known bitmap format options */
 154         {
 155                 uint32_t flags = ntohs(header->options);
 156                 size_t cache_size = st_mult(index->pack->num_objects, sizeof(uint32_t));
 157                 unsigned char *index_end = index->map + index->map_size - the_hash_algo->rawsz;
 158
 159                 if ((flags & BITMAP_OPT_FULL_DAG) == 0)
 160                         return error("Unsupported options for bitmap index file "
 161                                 "(Git requires BITMAP_OPT_FULL_DAG)");
 162
 163                 if (flags & BITMAP_OPT_HASH_CACHE) {
 164                         if (cache_size > index_end - index->map - header_size)
 165                                 return error("corrupted bitmap index file (too short to fit hash cache)");
 166                         index->hashes = (void *)(index_end - cache_size);
 167                         index_end -= cache_size;
 168                 }
 169         }
 170
 171         index->entry_count = ntohl(header->entry_count);
 172         index->map_pos += header_size;
 173         return 0;
 174 }
 175
 176 static struct stored_bitmap *store_bitmap(struct bitmap_index *index,
 177                                           struct ewah_bitmap *root,
 178                                           const struct object_id *oid,
 179                                           struct stored_bitmap *xor_with,
 180                                           int flags)
 181 {
 182         struct stored_bitmap *stored;
 183         khiter_t hash_pos;
 184         int ret;
 185
 186         stored = xmalloc(sizeof(struct stored_bitmap));
 187         stored->root = root;
 188         stored->xor = xor_with;
 189         stored->flags = flags;
 190         oidcpy(&stored->oid, oid);
 191
 192         hash_pos = kh_put_oid_map(index->bitmaps, stored->oid, &ret);
 193
 194         /* a 0 return code means the insertion succeeded with no changes,
 195          * because the SHA1 already existed on the map. this is bad, there
 196          * shouldn't be duplicated commits in the index */
 197         if (ret == 0) {
 198                 error("Duplicate entry in bitmap index: %s", oid_to_hex(oid));
 199                 return NULL;
 200         }
 201
 202         kh_value(index->bitmaps, hash_pos) = stored;
 203         return stored;
 204 }
 205
 206 static inline uint32_t read_be32(const unsigned char *buffer, size_t *pos)
 207 {
 208         uint32_t result = get_be32(buffer + *pos);
 209         (*pos) += sizeof(result);
 210         return result;
 211 }
 212
 213 static inline uint8_t read_u8(const unsigned char *buffer, size_t *pos)
 214 {
 215         return buffer[(*pos)++];
 216 }
 217
 218 #define MAX_XOR_OFFSET 160
 219
 220 static int load_bitmap_entries_v1(struct bitmap_index *index)
 221 {
 222         uint32_t i;
 223         struct stored_bitmap *recent_bitmaps[MAX_XOR_OFFSET] = { NULL };
 224
 225         for (i = 0; i < index->entry_count; ++i) {
 226                 int xor_offset, flags;
 227                 struct ewah_bitmap *bitmap = NULL;
 228                 struct stored_bitmap *xor_bitmap = NULL;
 229                 uint32_t commit_idx_pos;
 230                 struct object_id oid;
 231
 232                 commit_idx_pos = read_be32(index->map, &index->map_pos);
 233                 xor_offset = read_u8(index->map, &index->map_pos);
 234                 flags = read_u8(index->map, &index->map_pos);
 235
 236                 nth_packed_object_id(&oid, index->pack, commit_idx_pos);
 237
 238                 bitmap = read_bitmap_1(index);
 239                 if (!bitmap)
 240                         return -1;
 241
 242                 if (xor_offset > MAX_XOR_OFFSET || xor_offset > i)
 243                         return error("Corrupted bitmap pack index");
 244
 245                 if (xor_offset > 0) {
 246                         xor_bitmap = recent_bitmaps[(i - xor_offset) % MAX_XOR_OFFSET];
 247
 248                         if (xor_bitmap == NULL)
 249                                 return error("Invalid XOR offset in bitmap pack index");
 250                 }
 251
 252                 recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
 253                         index, bitmap, &oid, xor_bitmap, flags);
 254         }
 255
 256         return 0;
 257 }
 258
 259 static char *pack_bitmap_filename(struct packed_git *p)
 260 {
 261         size_t len;
 262
 263         if (!strip_suffix(p->pack_name, ".pack", &len))
 264                 BUG("pack_name does not end in .pack");
 265         return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
 266 }
 267
 268 static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git *packfile)
 269 {
 270         int fd;
 271         struct stat st;
 272         char *idx_name;
 273
 274         if (open_pack_index(packfile))
 275                 return -1;
 276
 277         idx_name = pack_bitmap_filename(packfile);
 278         fd = git_open(idx_name);
 279         free(idx_name);
 280
 281         if (fd < 0)
 282                 return -1;
 283
 284         if (fstat(fd, &st)) {
 285                 close(fd);
 286                 return -1;
 287         }
 288
 289         if (bitmap_git->pack) {
 290                 warning("ignoring extra bitmap file: %s", packfile->pack_name);
 291                 close(fd);
 292                 return -1;
 293         }
 294
 295         bitmap_git->pack = packfile;
 296         bitmap_git->map_size = xsize_t(st.st_size);
 297         bitmap_git->map = xmmap(NULL, bitmap_git->map_size, PROT_READ, MAP_PRIVATE, fd, 0);
 298         bitmap_git->map_pos = 0;
 299         close(fd);
 300
 301         if (load_bitmap_header(bitmap_git) < 0) {
 302                 munmap(bitmap_git->map, bitmap_git->map_size);
 303                 bitmap_git->map = NULL;
 304                 bitmap_git->map_size = 0;
 305                 return -1;
 306         }
 307
 308         return 0;
 309 }
 310
 311 static int load_pack_bitmap(struct bitmap_index *bitmap_git)
 312 {
 313         assert(bitmap_git->map);
 314
 315         bitmap_git->bitmaps = kh_init_oid_map();
 316         bitmap_git->ext_index.positions = kh_init_oid_pos();
 317         if (load_pack_revindex(bitmap_git->pack))
 318                 goto failed;
 319
 320         if (!(bitmap_git->commits = read_bitmap_1(bitmap_git)) ||
 321                 !(bitmap_git->trees = read_bitmap_1(bitmap_git)) ||
 322                 !(bitmap_git->blobs = read_bitmap_1(bitmap_git)) ||
 323                 !(bitmap_git->tags = read_bitmap_1(bitmap_git)))
 324                 goto failed;
 325
 326         if (load_bitmap_entries_v1(bitmap_git) < 0)
 327                 goto failed;
 328
 329         return 0;
 330
 331 failed:
 332         munmap(bitmap_git->map, bitmap_git->map_size);
 333         bitmap_git->map = NULL;
 334         bitmap_git->map_size = 0;
 335
 336         kh_destroy_oid_map(bitmap_git->bitmaps);
 337         bitmap_git->bitmaps = NULL;
 338
 339         kh_destroy_oid_pos(bitmap_git->ext_index.positions);
 340         bitmap_git->ext_index.positions = NULL;
 341
 342         return -1;
 343 }
 344
 345 static int open_pack_bitmap(struct repository *r,
 346                             struct bitmap_index *bitmap_git)
 347 {
 348         struct packed_git *p;
 349         int ret = -1;
 350
 351         assert(!bitmap_git->map);
 352
 353         for (p = get_all_packs(r); p; p = p->next) {
 354                 if (open_pack_bitmap_1(bitmap_git, p) == 0)
 355                         ret = 0;
 356         }
 357
 358         return ret;
 359 }
 360
 361 struct bitmap_index *prepare_bitmap_git(struct repository *r)
 362 {
 363         struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
 364
 365         if (!open_pack_bitmap(r, bitmap_git) && !load_pack_bitmap(bitmap_git))
 366                 return bitmap_git;
 367
 368         free_bitmap_index(bitmap_git);
 369         return NULL;
 370 }
 371
 372 struct include_data {
 373         struct bitmap_index *bitmap_git;
 374         struct bitmap *base;
 375         struct bitmap *seen;
 376 };
 377
 378 static inline int bitmap_position_extended(struct bitmap_index *bitmap_git,
 379                                            const struct object_id *oid)
 380 {
 381         kh_oid_pos_t *positions = bitmap_git->ext_index.positions;
 382         khiter_t pos = kh_get_oid_pos(positions, *oid);
 383
 384         if (pos < kh_end(positions)) {
 385                 int bitmap_pos = kh_value(positions, pos);
 386                 return bitmap_pos + bitmap_git->pack->num_objects;
 387         }
 388
 389         return -1;
 390 }
 391
 392 static inline int bitmap_position_packfile(struct bitmap_index *bitmap_git,
 393                                            const struct object_id *oid)
 394 {
 395         off_t offset = find_pack_entry_one(oid->hash, bitmap_git->pack);
 396         if (!offset)
 397                 return -1;
 398
 399         return find_revindex_position(bitmap_git->pack, offset);
 400 }
 401
 402 static int bitmap_position(struct bitmap_index *bitmap_git,
 403                            const struct object_id *oid)
 404 {
 405         int pos = bitmap_position_packfile(bitmap_git, oid);
 406         return (pos >= 0) ? pos : bitmap_position_extended(bitmap_git, oid);
 407 }
 408
 409 static int ext_index_add_object(struct bitmap_index *bitmap_git,
 410                                 struct object *object, const char *name)
 411 {
 412         struct eindex *eindex = &bitmap_git->ext_index;
 413
 414         khiter_t hash_pos;
 415         int hash_ret;
 416         int bitmap_pos;
 417
 418         hash_pos = kh_put_oid_pos(eindex->positions, object->oid, &hash_ret);
 419         if (hash_ret > 0) {
 420                 if (eindex->count >= eindex->alloc) {
 421                         eindex->alloc = (eindex->alloc + 16) * 3 / 2;
 422                         REALLOC_ARRAY(eindex->objects, eindex->alloc);
 423                         REALLOC_ARRAY(eindex->hashes, eindex->alloc);
 424                 }
 425
 426                 bitmap_pos = eindex->count;
 427                 eindex->objects[eindex->count] = object;
 428                 eindex->hashes[eindex->count] = pack_name_hash(name);
 429                 kh_value(eindex->positions, hash_pos) = bitmap_pos;
 430                 eindex->count++;
 431         } else {
 432                 bitmap_pos = kh_value(eindex->positions, hash_pos);
 433         }
 434
 435         return bitmap_pos + bitmap_git->pack->num_objects;
 436 }
 437
 438 struct bitmap_show_data {
 439         struct bitmap_index *bitmap_git;
 440         struct bitmap *base;
 441 };
 442
 443 static void show_object(struct object *object, const char *name, void *data_)
 444 {
 445         struct bitmap_show_data *data = data_;
 446         int bitmap_pos;
 447
 448         bitmap_pos = bitmap_position(data->bitmap_git, &object->oid);
 449
 450         if (bitmap_pos < 0)
 451                 bitmap_pos = ext_index_add_object(data->bitmap_git, object,
 452                                                   name);
 453
 454         bitmap_set(data->base, bitmap_pos);
 455 }
 456
 457 static void show_commit(struct commit *commit, void *data)
 458 {
 459 }
 460
 461 static int add_to_include_set(struct bitmap_index *bitmap_git,
 462                               struct include_data *data,
 463                               const struct object_id *oid,
 464                               int bitmap_pos)
 465 {
 466         khiter_t hash_pos;
 467
 468         if (data->seen && bitmap_get(data->seen, bitmap_pos))
 469                 return 0;
 470
 471         if (bitmap_get(data->base, bitmap_pos))
 472                 return 0;
 473
 474         hash_pos = kh_get_oid_map(bitmap_git->bitmaps, *oid);
 475         if (hash_pos < kh_end(bitmap_git->bitmaps)) {
 476                 struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, hash_pos);
 477                 bitmap_or_ewah(data->base, lookup_stored_bitmap(st));
 478                 return 0;
 479         }
 480
 481         bitmap_set(data->base, bitmap_pos);
 482         return 1;
 483 }
 484
 485 static int should_include(struct commit *commit, void *_data)
 486 {
 487         struct include_data *data = _data;
 488         int bitmap_pos;
 489
 490         bitmap_pos = bitmap_position(data->bitmap_git, &commit->object.oid);
 491         if (bitmap_pos < 0)
 492                 bitmap_pos = ext_index_add_object(data->bitmap_git,
 493                                                   (struct object *)commit,
 494                                                   NULL);
 495
 496         if (!add_to_include_set(data->bitmap_git, data, &commit->object.oid,
 497                                 bitmap_pos)) {
 498                 struct commit_list *parent = commit->parents;
 499
 500                 while (parent) {
 501                         parent->item->object.flags |= SEEN;
 502                         parent = parent->next;
 503                 }
 504
 505                 return 0;
 506         }
 507
 508         return 1;
 509 }
 510
 511 static struct bitmap *find_objects(struct bitmap_index *bitmap_git,
 512                                    struct rev_info *revs,
 513                                    struct object_list *roots,
 514                                    struct bitmap *seen,
 515                                    struct list_objects_filter_options *filter)
 516 {
 517         struct bitmap *base = NULL;
 518         int needs_walk = 0;
 519
 520         struct object_list *not_mapped = NULL;
 521
 522         /*
 523          * Go through all the roots for the walk. The ones that have bitmaps
 524          * on the bitmap index will be `or`ed together to form an initial
 525          * global reachability analysis.
 526          *
 527          * The ones without bitmaps in the index will be stored in the
 528          * `not_mapped_list` for further processing.
 529          */
 530         while (roots) {
 531                 struct object *object = roots->item;
 532                 roots = roots->next;
 533
 534                 if (object->type == OBJ_COMMIT) {
 535                         khiter_t pos = kh_get_oid_map(bitmap_git->bitmaps, object->oid);
 536
 537                         if (pos < kh_end(bitmap_git->bitmaps)) {
 538                                 struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, pos);
 539                                 struct ewah_bitmap *or_with = lookup_stored_bitmap(st);
 540
 541                                 if (base == NULL)
 542                                         base = ewah_to_bitmap(or_with);
 543                                 else
 544                                         bitmap_or_ewah(base, or_with);
 545
 546                                 object->flags |= SEEN;
 547                                 continue;
 548                         }
 549                 }
 550
 551                 object_list_insert(object, &not_mapped);
 552         }
 553
 554         /*
 555          * Best case scenario: We found bitmaps for all the roots,
 556          * so the resulting `or` bitmap has the full reachability analysis
 557          */
 558         if (not_mapped == NULL)
 559                 return base;
 560
 561         roots = not_mapped;
 562
 563         /*
 564          * Let's iterate through all the roots that don't have bitmaps to
 565          * check if we can determine them to be reachable from the existing
 566          * global bitmap.
 567          *
 568          * If we cannot find them in the existing global bitmap, we'll need
 569          * to push them to an actual walk and run it until we can confirm
 570          * they are reachable
 571          */
 572         while (roots) {
 573                 struct object *object = roots->item;
 574                 int pos;
 575
 576                 roots = roots->next;
 577                 pos = bitmap_position(bitmap_git, &object->oid);
 578
 579                 if (pos < 0 || base == NULL || !bitmap_get(base, pos)) {
 580                         object->flags &= ~UNINTERESTING;
 581                         add_pending_object(revs, object, "");
 582                         needs_walk = 1;
 583                 } else {
 584                         object->flags |= SEEN;
 585                 }
 586         }
 587
 588         if (needs_walk) {
 589                 struct include_data incdata;
 590                 struct bitmap_show_data show_data;
 591
 592                 if (base == NULL)
 593                         base = bitmap_new();
 594
 595                 incdata.bitmap_git = bitmap_git;
 596                 incdata.base = base;
 597                 incdata.seen = seen;
 598
 599                 revs->include_check = should_include;
 600                 revs->include_check_data = &incdata;
 601
 602                 if (prepare_revision_walk(revs))
 603                         die("revision walk setup failed");
 604
 605                 show_data.bitmap_git = bitmap_git;
 606                 show_data.base = base;
 607
 608                 traverse_commit_list_filtered(filter, revs,
 609                                               show_commit, show_object,
 610                                               &show_data, NULL);
 611         }
 612
 613         return base;
 614 }
 615
 616 static void show_extended_objects(struct bitmap_index *bitmap_git,
 617                                   struct rev_info *revs,
 618                                   show_reachable_fn show_reach)
 619 {
 620         struct bitmap *objects = bitmap_git->result;
 621         struct eindex *eindex = &bitmap_git->ext_index;
 622         uint32_t i;
 623
 624         for (i = 0; i < eindex->count; ++i) {
 625                 struct object *obj;
 626
 627                 if (!bitmap_get(objects, bitmap_git->pack->num_objects + i))
 628                         continue;
 629
 630                 obj = eindex->objects[i];
 631                 if ((obj->type == OBJ_BLOB && !revs->blob_objects) ||
 632                     (obj->type == OBJ_TREE && !revs->tree_objects) ||
 633                     (obj->type == OBJ_TAG && !revs->tag_objects))
 634                         continue;
 635
 636                 show_reach(&obj->oid, obj->type, 0, eindex->hashes[i], NULL, 0);
 637         }
 638 }
 639
 640 static void init_type_iterator(struct ewah_iterator *it,
 641                                struct bitmap_index *bitmap_git,
 642                                enum object_type type)
 643 {
 644         switch (type) {
 645         case OBJ_COMMIT:
 646                 ewah_iterator_init(it, bitmap_git->commits);
 647                 break;
 648
 649         case OBJ_TREE:
 650                 ewah_iterator_init(it, bitmap_git->trees);
 651                 break;
 652
 653         case OBJ_BLOB:
 654                 ewah_iterator_init(it, bitmap_git->blobs);
 655                 break;
 656
 657         case OBJ_TAG:
 658                 ewah_iterator_init(it, bitmap_git->tags);
 659                 break;
 660
 661         default:
 662                 BUG("object type %d not stored by bitmap type index", type);
 663                 break;
 664         }
 665 }
 666
 667 static void show_objects_for_type(
 668         struct bitmap_index *bitmap_git,
 669         enum object_type object_type,
 670         show_reachable_fn show_reach)
 671 {
 672         size_t i = 0;
 673         uint32_t offset;
 674
 675         struct ewah_iterator it;
 676         eword_t filter;
 677
 678         struct bitmap *objects = bitmap_git->result;
 679
 680         init_type_iterator(&it, bitmap_git, object_type);
 681
 682         for (i = 0; i < objects->word_alloc &&
 683                         ewah_iterator_next(&filter, &it); i++) {
 684                 eword_t word = objects->words[i] & filter;
 685                 size_t pos = (i * BITS_IN_EWORD);
 686
 687                 if (!word)
 688                         continue;
 689
 690                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
 691                         struct object_id oid;
 692                         struct revindex_entry *entry;
 693                         uint32_t hash = 0;
 694
 695                         if ((word >> offset) == 0)
 696                                 break;
 697
 698                         offset += ewah_bit_ctz64(word >> offset);
 699
 700                         entry = &bitmap_git->pack->revindex[pos + offset];
 701                         nth_packed_object_id(&oid, bitmap_git->pack, entry->nr);
 702
 703                         if (bitmap_git->hashes)
 704                                 hash = get_be32(bitmap_git->hashes + entry->nr);
 705
 706                         show_reach(&oid, object_type, 0, hash, bitmap_git->pack, entry->offset);
 707                 }
 708         }
 709 }
 710
 711 static int in_bitmapped_pack(struct bitmap_index *bitmap_git,
 712                              struct object_list *roots)
 713 {
 714         while (roots) {
 715                 struct object *object = roots->item;
 716                 roots = roots->next;
 717
 718                 if (find_pack_entry_one(object->oid.hash, bitmap_git->pack) > 0)
 719                         return 1;
 720         }
 721
 722         return 0;
 723 }
 724
 725 static struct bitmap *find_tip_objects(struct bitmap_index *bitmap_git,
 726                                        struct object_list *tip_objects,
 727                                        enum object_type type)
 728 {
 729         struct bitmap *result = bitmap_new();
 730         struct object_list *p;
 731
 732         for (p = tip_objects; p; p = p->next) {
 733                 int pos;
 734
 735                 if (p->item->type != type)
 736                         continue;
 737
 738                 pos = bitmap_position(bitmap_git, &p->item->oid);
 739                 if (pos < 0)
 740                         continue;
 741
 742                 bitmap_set(result, pos);
 743         }
 744
 745         return result;
 746 }
 747
 748 static void filter_bitmap_exclude_type(struct bitmap_index *bitmap_git,
 749                                        struct object_list *tip_objects,
 750                                        struct bitmap *to_filter,
 751                                        enum object_type type)
 752 {
 753         struct eindex *eindex = &bitmap_git->ext_index;
 754         struct bitmap *tips;
 755         struct ewah_iterator it;
 756         eword_t mask;
 757         uint32_t i;
 758
 759         if (type != OBJ_BLOB && type != OBJ_TREE)
 760                 BUG("filter_bitmap_exclude_type: unsupported type '%d'", type);
 761
 762         /*
 763          * The non-bitmap version of this filter never removes
 764          * objects which the other side specifically asked for,
 765          * so we must match that behavior.
 766          */
 767         tips = find_tip_objects(bitmap_git, tip_objects, type);
 768
 769         /*
 770          * We can use the blob type-bitmap to work in whole words
 771          * for the objects that are actually in the bitmapped packfile.
 772          */
 773         for (i = 0, init_type_iterator(&it, bitmap_git, type);
 774              i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
 775              i++) {
 776                 if (i < tips->word_alloc)
 777                         mask &= ~tips->words[i];
 778                 to_filter->words[i] &= ~mask;
 779         }
 780
 781         /*
 782          * Clear any blobs that weren't in the packfile (and so would not have
 783          * been caught by the loop above. We'll have to check them
 784          * individually.
 785          */
 786         for (i = 0; i < eindex->count; i++) {
 787                 uint32_t pos = i + bitmap_git->pack->num_objects;
 788                 if (eindex->objects[i]->type == type &&
 789                     bitmap_get(to_filter, pos) &&
 790                     !bitmap_get(tips, pos))
 791                         bitmap_unset(to_filter, pos);
 792         }
 793
 794         bitmap_free(tips);
 795 }
 796
 797 static void filter_bitmap_blob_none(struct bitmap_index *bitmap_git,
 798                                     struct object_list *tip_objects,
 799                                     struct bitmap *to_filter)
 800 {
 801         filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
 802                                    OBJ_BLOB);
 803 }
 804
 805 static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
 806                                      uint32_t pos)
 807 {
 808         struct packed_git *pack = bitmap_git->pack;
 809         unsigned long size;
 810         struct object_info oi = OBJECT_INFO_INIT;
 811
 812         oi.sizep = &size;
 813
 814         if (pos < pack->num_objects) {
 815                 struct revindex_entry *entry = &pack->revindex[pos];
 816                 if (packed_object_info(the_repository, pack,
 817                                        entry->offset, &oi) < 0) {
 818                         struct object_id oid;
 819                         nth_packed_object_id(&oid, pack, entry->nr);
 820                         die(_("unable to get size of %s"), oid_to_hex(&oid));
 821                 }
 822         } else {
 823                 struct eindex *eindex = &bitmap_git->ext_index;
 824                 struct object *obj = eindex->objects[pos - pack->num_objects];
 825                 if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
 826                         die(_("unable to get size of %s"), oid_to_hex(&obj->oid));
 827         }
 828
 829         return size;
 830 }
 831
 832 static void filter_bitmap_blob_limit(struct bitmap_index *bitmap_git,
 833                                      struct object_list *tip_objects,
 834                                      struct bitmap *to_filter,
 835                                      unsigned long limit)
 836 {
 837         struct eindex *eindex = &bitmap_git->ext_index;
 838         struct bitmap *tips;
 839         struct ewah_iterator it;
 840         eword_t mask;
 841         uint32_t i;
 842
 843         tips = find_tip_objects(bitmap_git, tip_objects, OBJ_BLOB);
 844
 845         for (i = 0, init_type_iterator(&it, bitmap_git, OBJ_BLOB);
 846              i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
 847              i++) {
 848                 eword_t word = to_filter->words[i] & mask;
 849                 unsigned offset;
 850
 851                 for (offset = 0; offset < BITS_IN_EWORD; offset++) {
 852                         uint32_t pos;
 853
 854                         if ((word >> offset) == 0)
 855                                 break;
 856                         offset += ewah_bit_ctz64(word >> offset);
 857                         pos = i * BITS_IN_EWORD + offset;
 858
 859                         if (!bitmap_get(tips, pos) &&
 860                             get_size_by_pos(bitmap_git, pos) >= limit)
 861                                 bitmap_unset(to_filter, pos);
 862                 }
 863         }
 864
 865         for (i = 0; i < eindex->count; i++) {
 866                 uint32_t pos = i + bitmap_git->pack->num_objects;
 867                 if (eindex->objects[i]->type == OBJ_BLOB &&
 868                     bitmap_get(to_filter, pos) &&
 869                     !bitmap_get(tips, pos) &&
 870                     get_size_by_pos(bitmap_git, pos) >= limit)
 871                         bitmap_unset(to_filter, pos);
 872         }
 873
 874         bitmap_free(tips);
 875 }
 876
 877 static void filter_bitmap_tree_depth(struct bitmap_index *bitmap_git,
 878                                      struct object_list *tip_objects,
 879                                      struct bitmap *to_filter,
 880                                      unsigned long limit)
 881 {
 882         if (limit)
 883                 BUG("filter_bitmap_tree_depth given non-zero limit");
 884
 885         filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
 886                                    OBJ_TREE);
 887         filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
 888                                    OBJ_BLOB);
 889 }
 890
 891 static int filter_bitmap(struct bitmap_index *bitmap_git,
 892                          struct object_list *tip_objects,
 893                          struct bitmap *to_filter,
 894                          struct list_objects_filter_options *filter)
 895 {
 896         if (!filter || filter->choice == LOFC_DISABLED)
 897                 return 0;
 898
 899         if (filter->choice == LOFC_BLOB_NONE) {
 900                 if (bitmap_git)
 901                         filter_bitmap_blob_none(bitmap_git, tip_objects,
 902                                                 to_filter);
 903                 return 0;
 904         }
 905
 906         if (filter->choice == LOFC_BLOB_LIMIT) {
 907                 if (bitmap_git)
 908                         filter_bitmap_blob_limit(bitmap_git, tip_objects,
 909                                                  to_filter,
 910                                                  filter->blob_limit_value);
 911                 return 0;
 912         }
 913
 914         if (filter->choice == LOFC_TREE_DEPTH &&
 915             filter->tree_exclude_depth == 0) {
 916                 if (bitmap_git)
 917                         filter_bitmap_tree_depth(bitmap_git, tip_objects,
 918                                                  to_filter,
 919                                                  filter->tree_exclude_depth);
 920                 return 0;
 921         }
 922
 923         /* filter choice not handled */
 924         return -1;
 925 }
 926
 927 static int can_filter_bitmap(struct list_objects_filter_options *filter)
 928 {
 929         return !filter_bitmap(NULL, NULL, NULL, filter);
 930 }
 931
 932 struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs,
 933                                          struct list_objects_filter_options *filter)
 934 {
 935         unsigned int i;
 936
 937         struct object_list *wants = NULL;
 938         struct object_list *haves = NULL;
 939
 940         struct bitmap *wants_bitmap = NULL;
 941         struct bitmap *haves_bitmap = NULL;
 942
 943         struct bitmap_index *bitmap_git;
 944
 945         /*
 946          * We can't do pathspec limiting with bitmaps, because we don't know
 947          * which commits are associated with which object changes (let alone
 948          * even which objects are associated with which paths).
 949          */
 950         if (revs->prune)
 951                 return NULL;
 952
 953         if (!can_filter_bitmap(filter))
 954                 return NULL;
 955
 956         /* try to open a bitmapped pack, but don't parse it yet
 957          * because we may not need to use it */
 958         bitmap_git = xcalloc(1, sizeof(*bitmap_git));
 959         if (open_pack_bitmap(revs->repo, bitmap_git) < 0)
 960                 goto cleanup;
 961
 962         for (i = 0; i < revs->pending.nr; ++i) {
 963                 struct object *object = revs->pending.objects[i].item;
 964
 965                 if (object->type == OBJ_NONE)
 966                         parse_object_or_die(&object->oid, NULL);
 967
 968                 while (object->type == OBJ_TAG) {
 969                         struct tag *tag = (struct tag *) object;
 970
 971                         if (object->flags & UNINTERESTING)
 972                                 object_list_insert(object, &haves);
 973                         else
 974                                 object_list_insert(object, &wants);
 975
 976                         object = parse_object_or_die(get_tagged_oid(tag), NULL);
 977                 }
 978
 979                 if (object->flags & UNINTERESTING)
 980                         object_list_insert(object, &haves);
 981                 else
 982                         object_list_insert(object, &wants);
 983         }
 984
 985         /*
 986          * if we have a HAVES list, but none of those haves is contained
 987          * in the packfile that has a bitmap, we don't have anything to
 988          * optimize here
 989          */
 990         if (haves && !in_bitmapped_pack(bitmap_git, haves))
 991                 goto cleanup;
 992
 993         /* if we don't want anything, we're done here */
 994         if (!wants)
 995                 goto cleanup;
 996
 997         /*
 998          * now we're going to use bitmaps, so load the actual bitmap entries
 999          * from disk. this is the point of no return; after this the rev_list
1000          * becomes invalidated and we must perform the revwalk through bitmaps
1001          */
1002         if (load_pack_bitmap(bitmap_git) < 0)
1003                 goto cleanup;
1004
1005         object_array_clear(&revs->pending);
1006
1007         if (haves) {
1008                 revs->ignore_missing_links = 1;
1009                 haves_bitmap = find_objects(bitmap_git, revs, haves, NULL,
1010                                             filter);
1011                 reset_revision_walk();
1012                 revs->ignore_missing_links = 0;
1013
1014                 if (haves_bitmap == NULL)
1015                         BUG("failed to perform bitmap walk");
1016         }
1017
1018         wants_bitmap = find_objects(bitmap_git, revs, wants, haves_bitmap,
1019                                     filter);
1020
1021         if (!wants_bitmap)
1022                 BUG("failed to perform bitmap walk");
1023
1024         if (haves_bitmap)
1025                 bitmap_and_not(wants_bitmap, haves_bitmap);
1026
1027         filter_bitmap(bitmap_git, wants, wants_bitmap, filter);
1028
1029         bitmap_git->result = wants_bitmap;
1030         bitmap_git->haves = haves_bitmap;
1031
1032         object_list_free(&wants);
1033         object_list_free(&haves);
1034
1035         return bitmap_git;
1036
1037 cleanup:
1038         free_bitmap_index(bitmap_git);
1039         object_list_free(&wants);
1040         object_list_free(&haves);
1041         return NULL;
1042 }
1043
1044 static void try_partial_reuse(struct bitmap_index *bitmap_git,
1045                               size_t pos,
1046                               struct bitmap *reuse,
1047                               struct pack_window **w_curs)
1048 {
1049         struct revindex_entry *revidx;
1050         off_t offset;
1051         enum object_type type;
1052         unsigned long size;
1053
1054         if (pos >= bitmap_git->pack->num_objects)
1055                 return; /* not actually in the pack */
1056
1057         revidx = &bitmap_git->pack->revindex[pos];
1058         offset = revidx->offset;
1059         type = unpack_object_header(bitmap_git->pack, w_curs, &offset, &size);
1060         if (type < 0)
1061                 return; /* broken packfile, punt */
1062
1063         if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA) {
1064                 off_t base_offset;
1065                 int base_pos;
1066
1067                 /*
1068                  * Find the position of the base object so we can look it up
1069                  * in our bitmaps. If we can't come up with an offset, or if
1070                  * that offset is not in the revidx, the pack is corrupt.
1071                  * There's nothing we can do, so just punt on this object,
1072                  * and the normal slow path will complain about it in
1073                  * more detail.
1074                  */
1075                 base_offset = get_delta_base(bitmap_git->pack, w_curs,
1076                                              &offset, type, revidx->offset);
1077                 if (!base_offset)
1078                         return;
1079                 base_pos = find_revindex_position(bitmap_git->pack, base_offset);
1080                 if (base_pos < 0)
1081                         return;
1082
1083                 /*
1084                  * We assume delta dependencies always point backwards. This
1085                  * lets us do a single pass, and is basically always true
1086                  * due to the way OFS_DELTAs work. You would not typically
1087                  * find REF_DELTA in a bitmapped pack, since we only bitmap
1088                  * packs we write fresh, and OFS_DELTA is the default). But
1089                  * let's double check to make sure the pack wasn't written with
1090                  * odd parameters.
1091                  */
1092                 if (base_pos >= pos)
1093                         return;
1094
1095                 /*
1096                  * And finally, if we're not sending the base as part of our
1097                  * reuse chunk, then don't send this object either. The base
1098                  * would come after us, along with other objects not
1099                  * necessarily in the pack, which means we'd need to convert
1100                  * to REF_DELTA on the fly. Better to just let the normal
1101                  * object_entry code path handle it.
1102                  */
1103                 if (!bitmap_get(reuse, base_pos))
1104                         return;
1105         }
1106
1107         /*
1108          * If we got here, then the object is OK to reuse. Mark it.
1109          */
1110         bitmap_set(reuse, pos);
1111 }
1112
1113 int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
1114                                        struct packed_git **packfile_out,
1115                                        uint32_t *entries,
1116                                        struct bitmap **reuse_out)
1117 {
1118         struct bitmap *result = bitmap_git->result;
1119         struct bitmap *reuse;
1120         struct pack_window *w_curs = NULL;
1121         size_t i = 0;
1122         uint32_t offset;
1123
1124         assert(result);
1125
1126         while (i < result->word_alloc && result->words[i] == (eword_t)~0)
1127                 i++;
1128
1129         /* Don't mark objects not in the packfile */
1130         if (i > bitmap_git->pack->num_objects / BITS_IN_EWORD)
1131                 i = bitmap_git->pack->num_objects / BITS_IN_EWORD;
1132
1133         reuse = bitmap_word_alloc(i);
1134         memset(reuse->words, 0xFF, i * sizeof(eword_t));
1135
1136         for (; i < result->word_alloc; ++i) {
1137                 eword_t word = result->words[i];
1138                 size_t pos = (i * BITS_IN_EWORD);
1139
1140                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
1141                         if ((word >> offset) == 0)
1142                                 break;
1143
1144                         offset += ewah_bit_ctz64(word >> offset);
1145                         try_partial_reuse(bitmap_git, pos + offset, reuse, &w_curs);
1146                 }
1147         }
1148
1149         unuse_pack(&w_curs);
1150
1151         *entries = bitmap_popcount(reuse);
1152         if (!*entries) {
1153                 bitmap_free(reuse);
1154                 return -1;
1155         }
1156
1157         /*
1158          * Drop any reused objects from the result, since they will not
1159          * need to be handled separately.
1160          */
1161         bitmap_and_not(result, reuse);
1162         *packfile_out = bitmap_git->pack;
1163         *reuse_out = reuse;
1164         return 0;
1165 }
1166
1167 int bitmap_walk_contains(struct bitmap_index *bitmap_git,
1168                          struct bitmap *bitmap, const struct object_id *oid)
1169 {
1170         int idx;
1171
1172         if (!bitmap)
1173                 return 0;
1174
1175         idx = bitmap_position(bitmap_git, oid);
1176         return idx >= 0 && bitmap_get(bitmap, idx);
1177 }
1178
1179 void traverse_bitmap_commit_list(struct bitmap_index *bitmap_git,
1180                                  struct rev_info *revs,
1181                                  show_reachable_fn show_reachable)
1182 {
1183         assert(bitmap_git->result);
1184
1185         show_objects_for_type(bitmap_git, OBJ_COMMIT, show_reachable);
1186         if (revs->tree_objects)
1187                 show_objects_for_type(bitmap_git, OBJ_TREE, show_reachable);
1188         if (revs->blob_objects)
1189                 show_objects_for_type(bitmap_git, OBJ_BLOB, show_reachable);
1190         if (revs->tag_objects)
1191                 show_objects_for_type(bitmap_git, OBJ_TAG, show_reachable);
1192
1193         show_extended_objects(bitmap_git, revs, show_reachable);
1194 }
1195
1196 static uint32_t count_object_type(struct bitmap_index *bitmap_git,
1197                                   enum object_type type)
1198 {
1199         struct bitmap *objects = bitmap_git->result;
1200         struct eindex *eindex = &bitmap_git->ext_index;
1201
1202         uint32_t i = 0, count = 0;
1203         struct ewah_iterator it;
1204         eword_t filter;
1205
1206         init_type_iterator(&it, bitmap_git, type);
1207
1208         while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
1209                 eword_t word = objects->words[i++] & filter;
1210                 count += ewah_bit_popcount64(word);
1211         }
1212
1213         for (i = 0; i < eindex->count; ++i) {
1214                 if (eindex->objects[i]->type == type &&
1215                         bitmap_get(objects, bitmap_git->pack->num_objects + i))
1216                         count++;
1217         }
1218
1219         return count;
1220 }
1221
1222 void count_bitmap_commit_list(struct bitmap_index *bitmap_git,
1223                               uint32_t *commits, uint32_t *trees,
1224                               uint32_t *blobs, uint32_t *tags)
1225 {
1226         assert(bitmap_git->result);
1227
1228         if (commits)
1229                 *commits = count_object_type(bitmap_git, OBJ_COMMIT);
1230
1231         if (trees)
1232                 *trees = count_object_type(bitmap_git, OBJ_TREE);
1233
1234         if (blobs)
1235                 *blobs = count_object_type(bitmap_git, OBJ_BLOB);
1236
1237         if (tags)
1238                 *tags = count_object_type(bitmap_git, OBJ_TAG);
1239 }
1240
1241 struct bitmap_test_data {
1242         struct bitmap_index *bitmap_git;
1243         struct bitmap *base;
1244         struct progress *prg;
1245         size_t seen;
1246 };
1247
1248 static void test_show_object(struct object *object, const char *name,
1249                              void *data)
1250 {
1251         struct bitmap_test_data *tdata = data;
1252         int bitmap_pos;
1253
1254         bitmap_pos = bitmap_position(tdata->bitmap_git, &object->oid);
1255         if (bitmap_pos < 0)
1256                 die("Object not in bitmap: %s\n", oid_to_hex(&object->oid));
1257
1258         bitmap_set(tdata->base, bitmap_pos);
1259         display_progress(tdata->prg, ++tdata->seen);
1260 }
1261
1262 static void test_show_commit(struct commit *commit, void *data)
1263 {
1264         struct bitmap_test_data *tdata = data;
1265         int bitmap_pos;
1266
1267         bitmap_pos = bitmap_position(tdata->bitmap_git,
1268                                      &commit->object.oid);
1269         if (bitmap_pos < 0)
1270                 die("Object not in bitmap: %s\n", oid_to_hex(&commit->object.oid));
1271
1272         bitmap_set(tdata->base, bitmap_pos);
1273         display_progress(tdata->prg, ++tdata->seen);
1274 }
1275
1276 void test_bitmap_walk(struct rev_info *revs)
1277 {
1278         struct object *root;
1279         struct bitmap *result = NULL;
1280         khiter_t pos;
1281         size_t result_popcnt;
1282         struct bitmap_test_data tdata;
1283         struct bitmap_index *bitmap_git;
1284
1285         if (!(bitmap_git = prepare_bitmap_git(revs->repo)))
1286                 die("failed to load bitmap indexes");
1287
1288         if (revs->pending.nr != 1)
1289                 die("you must specify exactly one commit to test");
1290
1291         fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
1292                 bitmap_git->version, bitmap_git->entry_count);
1293
1294         root = revs->pending.objects[0].item;
1295         pos = kh_get_oid_map(bitmap_git->bitmaps, root->oid);
1296
1297         if (pos < kh_end(bitmap_git->bitmaps)) {
1298                 struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, pos);
1299                 struct ewah_bitmap *bm = lookup_stored_bitmap(st);
1300
1301                 fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
1302                         oid_to_hex(&root->oid), (int)bm->bit_size, ewah_checksum(bm));
1303
1304                 result = ewah_to_bitmap(bm);
1305         }
1306
1307         if (result == NULL)
1308                 die("Commit %s doesn't have an indexed bitmap", oid_to_hex(&root->oid));
1309
1310         revs->tag_objects = 1;
1311         revs->tree_objects = 1;
1312         revs->blob_objects = 1;
1313
1314         result_popcnt = bitmap_popcount(result);
1315
1316         if (prepare_revision_walk(revs))
1317                 die("revision walk setup failed");
1318
1319         tdata.bitmap_git = bitmap_git;
1320         tdata.base = bitmap_new();
1321         tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
1322         tdata.seen = 0;
1323
1324         traverse_commit_list(revs, &test_show_commit, &test_show_object, &tdata);
1325
1326         stop_progress(&tdata.prg);
1327
1328         if (bitmap_equals(result, tdata.base))
1329                 fprintf(stderr, "OK!\n");
1330         else
1331                 die("mismatch in bitmap results");
1332
1333         free_bitmap_index(bitmap_git);
1334 }
1335
1336 static int rebuild_bitmap(uint32_t *reposition,
1337                           struct ewah_bitmap *source,
1338                           struct bitmap *dest)
1339 {
1340         uint32_t pos = 0;
1341         struct ewah_iterator it;
1342         eword_t word;
1343
1344         ewah_iterator_init(&it, source);
1345
1346         while (ewah_iterator_next(&word, &it)) {
1347                 uint32_t offset, bit_pos;
1348
1349                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
1350                         if ((word >> offset) == 0)
1351                                 break;
1352
1353                         offset += ewah_bit_ctz64(word >> offset);
1354
1355                         bit_pos = reposition[pos + offset];
1356                         if (bit_pos > 0)
1357                                 bitmap_set(dest, bit_pos - 1);
1358                         else /* can't reuse, we don't have the object */
1359                                 return -1;
1360                 }
1361
1362                 pos += BITS_IN_EWORD;
1363         }
1364         return 0;
1365 }
1366
1367 int rebuild_existing_bitmaps(struct bitmap_index *bitmap_git,
1368                              struct packing_data *mapping,
1369                              kh_oid_map_t *reused_bitmaps,
1370                              int show_progress)
1371 {
1372         uint32_t i, num_objects;
1373         uint32_t *reposition;
1374         struct bitmap *rebuild;
1375         struct stored_bitmap *stored;
1376         struct progress *progress = NULL;
1377
1378         khiter_t hash_pos;
1379         int hash_ret;
1380
1381         num_objects = bitmap_git->pack->num_objects;
1382         reposition = xcalloc(num_objects, sizeof(uint32_t));
1383
1384         for (i = 0; i < num_objects; ++i) {
1385                 struct object_id oid;
1386                 struct revindex_entry *entry;
1387                 struct object_entry *oe;
1388
1389                 entry = &bitmap_git->pack->revindex[i];
1390                 nth_packed_object_id(&oid, bitmap_git->pack, entry->nr);
1391                 oe = packlist_find(mapping, &oid);
1392
1393                 if (oe)
1394                         reposition[i] = oe_in_pack_pos(mapping, oe) + 1;
1395         }
1396
1397         rebuild = bitmap_new();
1398         i = 0;
1399
1400         if (show_progress)
1401                 progress = start_progress("Reusing bitmaps", 0);
1402
1403         kh_foreach_value(bitmap_git->bitmaps, stored, {
1404                 if (stored->flags & BITMAP_FLAG_REUSE) {
1405                         if (!rebuild_bitmap(reposition,
1406                                             lookup_stored_bitmap(stored),
1407                                             rebuild)) {
1408                                 hash_pos = kh_put_oid_map(reused_bitmaps,
1409                                                           stored->oid,
1410                                                           &hash_ret);
1411                                 kh_value(reused_bitmaps, hash_pos) =
1412                                         bitmap_to_ewah(rebuild);
1413                         }
1414                         bitmap_reset(rebuild);
1415                         display_progress(progress, ++i);
1416                 }
1417         });
1418
1419         stop_progress(&progress);
1420
1421         free(reposition);
1422         bitmap_free(rebuild);
1423         return 0;
1424 }
1425
1426 void free_bitmap_index(struct bitmap_index *b)
1427 {
1428         if (!b)
1429                 return;
1430
1431         if (b->map)
1432                 munmap(b->map, b->map_size);
1433         ewah_pool_free(b->commits);
1434         ewah_pool_free(b->trees);
1435         ewah_pool_free(b->blobs);
1436         ewah_pool_free(b->tags);
1437         kh_destroy_oid_map(b->bitmaps);
1438         free(b->ext_index.objects);
1439         free(b->ext_index.hashes);
1440         bitmap_free(b->result);
1441         bitmap_free(b->haves);
1442         free(b);
1443 }
1444
1445 int bitmap_has_oid_in_uninteresting(struct bitmap_index *bitmap_git,
1446                                     const struct object_id *oid)
1447 {
1448         return bitmap_git &&
1449                 bitmap_walk_contains(bitmap_git, bitmap_git->haves, oid);
1450 }