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                 if (index->map_size - index->map_pos < 6)
 233                         return error("corrupt ewah bitmap: truncated header for entry %d", i);
 234
 235                 commit_idx_pos = read_be32(index->map, &index->map_pos);
 236                 xor_offset = read_u8(index->map, &index->map_pos);
 237                 flags = read_u8(index->map, &index->map_pos);
 238
 239                 if (nth_packed_object_id(&oid, index->pack, commit_idx_pos) < 0)
 240                         return error("corrupt ewah bitmap: commit index %u out of range",
 241                                      (unsigned)commit_idx_pos);
 242
 243                 bitmap = read_bitmap_1(index);
 244                 if (!bitmap)
 245                         return -1;
 246
 247                 if (xor_offset > MAX_XOR_OFFSET || xor_offset > i)
 248                         return error("Corrupted bitmap pack index");
 249
 250                 if (xor_offset > 0) {
 251                         xor_bitmap = recent_bitmaps[(i - xor_offset) % MAX_XOR_OFFSET];
 252
 253                         if (xor_bitmap == NULL)
 254                                 return error("Invalid XOR offset in bitmap pack index");
 255                 }
 256
 257                 recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
 258                         index, bitmap, &oid, xor_bitmap, flags);
 259         }
 260
 261         return 0;
 262 }
 263
 264 static char *pack_bitmap_filename(struct packed_git *p)
 265 {
 266         size_t len;
 267
 268         if (!strip_suffix(p->pack_name, ".pack", &len))
 269                 BUG("pack_name does not end in .pack");
 270         return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
 271 }
 272
 273 static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git *packfile)
 274 {
 275         int fd;
 276         struct stat st;
 277         char *idx_name;
 278
 279         if (open_pack_index(packfile))
 280                 return -1;
 281
 282         idx_name = pack_bitmap_filename(packfile);
 283         fd = git_open(idx_name);
 284         free(idx_name);
 285
 286         if (fd < 0)
 287                 return -1;
 288
 289         if (fstat(fd, &st)) {
 290                 close(fd);
 291                 return -1;
 292         }
 293
 294         if (bitmap_git->pack) {
 295                 warning("ignoring extra bitmap file: %s", packfile->pack_name);
 296                 close(fd);
 297                 return -1;
 298         }
 299
 300         bitmap_git->pack = packfile;
 301         bitmap_git->map_size = xsize_t(st.st_size);
 302         bitmap_git->map = xmmap(NULL, bitmap_git->map_size, PROT_READ, MAP_PRIVATE, fd, 0);
 303         bitmap_git->map_pos = 0;
 304         close(fd);
 305
 306         if (load_bitmap_header(bitmap_git) < 0) {
 307                 munmap(bitmap_git->map, bitmap_git->map_size);
 308                 bitmap_git->map = NULL;
 309                 bitmap_git->map_size = 0;
 310                 return -1;
 311         }
 312
 313         return 0;
 314 }
 315
 316 static int load_pack_bitmap(struct bitmap_index *bitmap_git)
 317 {
 318         assert(bitmap_git->map);
 319
 320         bitmap_git->bitmaps = kh_init_oid_map();
 321         bitmap_git->ext_index.positions = kh_init_oid_pos();
 322         if (load_pack_revindex(bitmap_git->pack))
 323                 goto failed;
 324
 325         if (!(bitmap_git->commits = read_bitmap_1(bitmap_git)) ||
 326                 !(bitmap_git->trees = read_bitmap_1(bitmap_git)) ||
 327                 !(bitmap_git->blobs = read_bitmap_1(bitmap_git)) ||
 328                 !(bitmap_git->tags = read_bitmap_1(bitmap_git)))
 329                 goto failed;
 330
 331         if (load_bitmap_entries_v1(bitmap_git) < 0)
 332                 goto failed;
 333
 334         return 0;
 335
 336 failed:
 337         munmap(bitmap_git->map, bitmap_git->map_size);
 338         bitmap_git->map = NULL;
 339         bitmap_git->map_size = 0;
 340
 341         kh_destroy_oid_map(bitmap_git->bitmaps);
 342         bitmap_git->bitmaps = NULL;
 343
 344         kh_destroy_oid_pos(bitmap_git->ext_index.positions);
 345         bitmap_git->ext_index.positions = NULL;
 346
 347         return -1;
 348 }
 349
 350 static int open_pack_bitmap(struct repository *r,
 351                             struct bitmap_index *bitmap_git)
 352 {
 353         struct packed_git *p;
 354         int ret = -1;
 355
 356         assert(!bitmap_git->map);
 357
 358         for (p = get_all_packs(r); p; p = p->next) {
 359                 if (open_pack_bitmap_1(bitmap_git, p) == 0)
 360                         ret = 0;
 361         }
 362
 363         return ret;
 364 }
 365
 366 struct bitmap_index *prepare_bitmap_git(struct repository *r)
 367 {
 368         struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
 369
 370         if (!open_pack_bitmap(r, bitmap_git) && !load_pack_bitmap(bitmap_git))
 371                 return bitmap_git;
 372
 373         free_bitmap_index(bitmap_git);
 374         return NULL;
 375 }
 376
 377 struct include_data {
 378         struct bitmap_index *bitmap_git;
 379         struct bitmap *base;
 380         struct bitmap *seen;
 381 };
 382
 383 struct ewah_bitmap *bitmap_for_commit(struct bitmap_index *bitmap_git,
 384                                       struct commit *commit)
 385 {
 386         khiter_t hash_pos = kh_get_oid_map(bitmap_git->bitmaps,
 387                                            commit->object.oid);
 388         if (hash_pos >= kh_end(bitmap_git->bitmaps))
 389                 return NULL;
 390         return lookup_stored_bitmap(kh_value(bitmap_git->bitmaps, hash_pos));
 391 }
 392
 393 static inline int bitmap_position_extended(struct bitmap_index *bitmap_git,
 394                                            const struct object_id *oid)
 395 {
 396         kh_oid_pos_t *positions = bitmap_git->ext_index.positions;
 397         khiter_t pos = kh_get_oid_pos(positions, *oid);
 398
 399         if (pos < kh_end(positions)) {
 400                 int bitmap_pos = kh_value(positions, pos);
 401                 return bitmap_pos + bitmap_git->pack->num_objects;
 402         }
 403
 404         return -1;
 405 }
 406
 407 static inline int bitmap_position_packfile(struct bitmap_index *bitmap_git,
 408                                            const struct object_id *oid)
 409 {
 410         uint32_t pos;
 411         off_t offset = find_pack_entry_one(oid->hash, bitmap_git->pack);
 412         if (!offset)
 413                 return -1;
 414
 415         if (offset_to_pack_pos(bitmap_git->pack, offset, &pos) < 0)
 416                 return -1;
 417         return pos;
 418 }
 419
 420 static int bitmap_position(struct bitmap_index *bitmap_git,
 421                            const struct object_id *oid)
 422 {
 423         int pos = bitmap_position_packfile(bitmap_git, oid);
 424         return (pos >= 0) ? pos : bitmap_position_extended(bitmap_git, oid);
 425 }
 426
 427 static int ext_index_add_object(struct bitmap_index *bitmap_git,
 428                                 struct object *object, const char *name)
 429 {
 430         struct eindex *eindex = &bitmap_git->ext_index;
 431
 432         khiter_t hash_pos;
 433         int hash_ret;
 434         int bitmap_pos;
 435
 436         hash_pos = kh_put_oid_pos(eindex->positions, object->oid, &hash_ret);
 437         if (hash_ret > 0) {
 438                 if (eindex->count >= eindex->alloc) {
 439                         eindex->alloc = (eindex->alloc + 16) * 3 / 2;
 440                         REALLOC_ARRAY(eindex->objects, eindex->alloc);
 441                         REALLOC_ARRAY(eindex->hashes, eindex->alloc);
 442                 }
 443
 444                 bitmap_pos = eindex->count;
 445                 eindex->objects[eindex->count] = object;
 446                 eindex->hashes[eindex->count] = pack_name_hash(name);
 447                 kh_value(eindex->positions, hash_pos) = bitmap_pos;
 448                 eindex->count++;
 449         } else {
 450                 bitmap_pos = kh_value(eindex->positions, hash_pos);
 451         }
 452
 453         return bitmap_pos + bitmap_git->pack->num_objects;
 454 }
 455
 456 struct bitmap_show_data {
 457         struct bitmap_index *bitmap_git;
 458         struct bitmap *base;
 459 };
 460
 461 static void show_object(struct object *object, const char *name, void *data_)
 462 {
 463         struct bitmap_show_data *data = data_;
 464         int bitmap_pos;
 465
 466         bitmap_pos = bitmap_position(data->bitmap_git, &object->oid);
 467
 468         if (bitmap_pos < 0)
 469                 bitmap_pos = ext_index_add_object(data->bitmap_git, object,
 470                                                   name);
 471
 472         bitmap_set(data->base, bitmap_pos);
 473 }
 474
 475 static void show_commit(struct commit *commit, void *data)
 476 {
 477 }
 478
 479 static int add_to_include_set(struct bitmap_index *bitmap_git,
 480                               struct include_data *data,
 481                               struct commit *commit,
 482                               int bitmap_pos)
 483 {
 484         struct ewah_bitmap *partial;
 485
 486         if (data->seen && bitmap_get(data->seen, bitmap_pos))
 487                 return 0;
 488
 489         if (bitmap_get(data->base, bitmap_pos))
 490                 return 0;
 491
 492         partial = bitmap_for_commit(bitmap_git, commit);
 493         if (partial) {
 494                 bitmap_or_ewah(data->base, partial);
 495                 return 0;
 496         }
 497
 498         bitmap_set(data->base, bitmap_pos);
 499         return 1;
 500 }
 501
 502 static int should_include(struct commit *commit, void *_data)
 503 {
 504         struct include_data *data = _data;
 505         int bitmap_pos;
 506
 507         bitmap_pos = bitmap_position(data->bitmap_git, &commit->object.oid);
 508         if (bitmap_pos < 0)
 509                 bitmap_pos = ext_index_add_object(data->bitmap_git,
 510                                                   (struct object *)commit,
 511                                                   NULL);
 512
 513         if (!add_to_include_set(data->bitmap_git, data, commit, bitmap_pos)) {
 514                 struct commit_list *parent = commit->parents;
 515
 516                 while (parent) {
 517                         parent->item->object.flags |= SEEN;
 518                         parent = parent->next;
 519                 }
 520
 521                 return 0;
 522         }
 523
 524         return 1;
 525 }
 526
 527 static int add_commit_to_bitmap(struct bitmap_index *bitmap_git,
 528                                 struct bitmap **base,
 529                                 struct commit *commit)
 530 {
 531         struct ewah_bitmap *or_with = bitmap_for_commit(bitmap_git, commit);
 532
 533         if (!or_with)
 534                 return 0;
 535
 536         if (*base == NULL)
 537                 *base = ewah_to_bitmap(or_with);
 538         else
 539                 bitmap_or_ewah(*base, or_with);
 540
 541         return 1;
 542 }
 543
 544 static struct bitmap *find_objects(struct bitmap_index *bitmap_git,
 545                                    struct rev_info *revs,
 546                                    struct object_list *roots,
 547                                    struct bitmap *seen,
 548                                    struct list_objects_filter_options *filter)
 549 {
 550         struct bitmap *base = NULL;
 551         int needs_walk = 0;
 552
 553         struct object_list *not_mapped = NULL;
 554
 555         /*
 556          * Go through all the roots for the walk. The ones that have bitmaps
 557          * on the bitmap index will be `or`ed together to form an initial
 558          * global reachability analysis.
 559          *
 560          * The ones without bitmaps in the index will be stored in the
 561          * `not_mapped_list` for further processing.
 562          */
 563         while (roots) {
 564                 struct object *object = roots->item;
 565                 roots = roots->next;
 566
 567                 if (object->type == OBJ_COMMIT &&
 568                     add_commit_to_bitmap(bitmap_git, &base, (struct commit *)object)) {
 569                         object->flags |= SEEN;
 570                         continue;
 571                 }
 572
 573                 object_list_insert(object, &not_mapped);
 574         }
 575
 576         /*
 577          * Best case scenario: We found bitmaps for all the roots,
 578          * so the resulting `or` bitmap has the full reachability analysis
 579          */
 580         if (not_mapped == NULL)
 581                 return base;
 582
 583         roots = not_mapped;
 584
 585         /*
 586          * Let's iterate through all the roots that don't have bitmaps to
 587          * check if we can determine them to be reachable from the existing
 588          * global bitmap.
 589          *
 590          * If we cannot find them in the existing global bitmap, we'll need
 591          * to push them to an actual walk and run it until we can confirm
 592          * they are reachable
 593          */
 594         while (roots) {
 595                 struct object *object = roots->item;
 596                 int pos;
 597
 598                 roots = roots->next;
 599                 pos = bitmap_position(bitmap_git, &object->oid);
 600
 601                 if (pos < 0 || base == NULL || !bitmap_get(base, pos)) {
 602                         object->flags &= ~UNINTERESTING;
 603                         add_pending_object(revs, object, "");
 604                         needs_walk = 1;
 605                 } else {
 606                         object->flags |= SEEN;
 607                 }
 608         }
 609
 610         if (needs_walk) {
 611                 struct include_data incdata;
 612                 struct bitmap_show_data show_data;
 613
 614                 if (base == NULL)
 615                         base = bitmap_new();
 616
 617                 incdata.bitmap_git = bitmap_git;
 618                 incdata.base = base;
 619                 incdata.seen = seen;
 620
 621                 revs->include_check = should_include;
 622                 revs->include_check_data = &incdata;
 623
 624                 if (prepare_revision_walk(revs))
 625                         die("revision walk setup failed");
 626
 627                 show_data.bitmap_git = bitmap_git;
 628                 show_data.base = base;
 629
 630                 traverse_commit_list_filtered(filter, revs,
 631                                               show_commit, show_object,
 632                                               &show_data, NULL);
 633         }
 634
 635         return base;
 636 }
 637
 638 static void show_extended_objects(struct bitmap_index *bitmap_git,
 639                                   struct rev_info *revs,
 640                                   show_reachable_fn show_reach)
 641 {
 642         struct bitmap *objects = bitmap_git->result;
 643         struct eindex *eindex = &bitmap_git->ext_index;
 644         uint32_t i;
 645
 646         for (i = 0; i < eindex->count; ++i) {
 647                 struct object *obj;
 648
 649                 if (!bitmap_get(objects, bitmap_git->pack->num_objects + i))
 650                         continue;
 651
 652                 obj = eindex->objects[i];
 653                 if ((obj->type == OBJ_BLOB && !revs->blob_objects) ||
 654                     (obj->type == OBJ_TREE && !revs->tree_objects) ||
 655                     (obj->type == OBJ_TAG && !revs->tag_objects))
 656                         continue;
 657
 658                 show_reach(&obj->oid, obj->type, 0, eindex->hashes[i], NULL, 0);
 659         }
 660 }
 661
 662 static void init_type_iterator(struct ewah_iterator *it,
 663                                struct bitmap_index *bitmap_git,
 664                                enum object_type type)
 665 {
 666         switch (type) {
 667         case OBJ_COMMIT:
 668                 ewah_iterator_init(it, bitmap_git->commits);
 669                 break;
 670
 671         case OBJ_TREE:
 672                 ewah_iterator_init(it, bitmap_git->trees);
 673                 break;
 674
 675         case OBJ_BLOB:
 676                 ewah_iterator_init(it, bitmap_git->blobs);
 677                 break;
 678
 679         case OBJ_TAG:
 680                 ewah_iterator_init(it, bitmap_git->tags);
 681                 break;
 682
 683         default:
 684                 BUG("object type %d not stored by bitmap type index", type);
 685                 break;
 686         }
 687 }
 688
 689 static void show_objects_for_type(
 690         struct bitmap_index *bitmap_git,
 691         enum object_type object_type,
 692         show_reachable_fn show_reach)
 693 {
 694         size_t i = 0;
 695         uint32_t offset;
 696
 697         struct ewah_iterator it;
 698         eword_t filter;
 699
 700         struct bitmap *objects = bitmap_git->result;
 701
 702         init_type_iterator(&it, bitmap_git, object_type);
 703
 704         for (i = 0; i < objects->word_alloc &&
 705                         ewah_iterator_next(&filter, &it); i++) {
 706                 eword_t word = objects->words[i] & filter;
 707                 size_t pos = (i * BITS_IN_EWORD);
 708
 709                 if (!word)
 710                         continue;
 711
 712                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
 713                         struct object_id oid;
 714                         uint32_t hash = 0, index_pos;
 715                         off_t ofs;
 716
 717                         if ((word >> offset) == 0)
 718                                 break;
 719
 720                         offset += ewah_bit_ctz64(word >> offset);
 721
 722                         index_pos = pack_pos_to_index(bitmap_git->pack, pos + offset);
 723                         ofs = pack_pos_to_offset(bitmap_git->pack, pos + offset);
 724                         nth_packed_object_id(&oid, bitmap_git->pack, index_pos);
 725
 726                         if (bitmap_git->hashes)
 727                                 hash = get_be32(bitmap_git->hashes + index_pos);
 728
 729                         show_reach(&oid, object_type, 0, hash, bitmap_git->pack, ofs);
 730                 }
 731         }
 732 }
 733
 734 static int in_bitmapped_pack(struct bitmap_index *bitmap_git,
 735                              struct object_list *roots)
 736 {
 737         while (roots) {
 738                 struct object *object = roots->item;
 739                 roots = roots->next;
 740
 741                 if (find_pack_entry_one(object->oid.hash, bitmap_git->pack) > 0)
 742                         return 1;
 743         }
 744
 745         return 0;
 746 }
 747
 748 static struct bitmap *find_tip_objects(struct bitmap_index *bitmap_git,
 749                                        struct object_list *tip_objects,
 750                                        enum object_type type)
 751 {
 752         struct bitmap *result = bitmap_new();
 753         struct object_list *p;
 754
 755         for (p = tip_objects; p; p = p->next) {
 756                 int pos;
 757
 758                 if (p->item->type != type)
 759                         continue;
 760
 761                 pos = bitmap_position(bitmap_git, &p->item->oid);
 762                 if (pos < 0)
 763                         continue;
 764
 765                 bitmap_set(result, pos);
 766         }
 767
 768         return result;
 769 }
 770
 771 static void filter_bitmap_exclude_type(struct bitmap_index *bitmap_git,
 772                                        struct object_list *tip_objects,
 773                                        struct bitmap *to_filter,
 774                                        enum object_type type)
 775 {
 776         struct eindex *eindex = &bitmap_git->ext_index;
 777         struct bitmap *tips;
 778         struct ewah_iterator it;
 779         eword_t mask;
 780         uint32_t i;
 781
 782         if (type != OBJ_BLOB && type != OBJ_TREE)
 783                 BUG("filter_bitmap_exclude_type: unsupported type '%d'", type);
 784
 785         /*
 786          * The non-bitmap version of this filter never removes
 787          * objects which the other side specifically asked for,
 788          * so we must match that behavior.
 789          */
 790         tips = find_tip_objects(bitmap_git, tip_objects, type);
 791
 792         /*
 793          * We can use the blob type-bitmap to work in whole words
 794          * for the objects that are actually in the bitmapped packfile.
 795          */
 796         for (i = 0, init_type_iterator(&it, bitmap_git, type);
 797              i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
 798              i++) {
 799                 if (i < tips->word_alloc)
 800                         mask &= ~tips->words[i];
 801                 to_filter->words[i] &= ~mask;
 802         }
 803
 804         /*
 805          * Clear any blobs that weren't in the packfile (and so would not have
 806          * been caught by the loop above. We'll have to check them
 807          * individually.
 808          */
 809         for (i = 0; i < eindex->count; i++) {
 810                 uint32_t pos = i + bitmap_git->pack->num_objects;
 811                 if (eindex->objects[i]->type == type &&
 812                     bitmap_get(to_filter, pos) &&
 813                     !bitmap_get(tips, pos))
 814                         bitmap_unset(to_filter, pos);
 815         }
 816
 817         bitmap_free(tips);
 818 }
 819
 820 static void filter_bitmap_blob_none(struct bitmap_index *bitmap_git,
 821                                     struct object_list *tip_objects,
 822                                     struct bitmap *to_filter)
 823 {
 824         filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
 825                                    OBJ_BLOB);
 826 }
 827
 828 static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
 829                                      uint32_t pos)
 830 {
 831         struct packed_git *pack = bitmap_git->pack;
 832         unsigned long size;
 833         struct object_info oi = OBJECT_INFO_INIT;
 834
 835         oi.sizep = &size;
 836
 837         if (pos < pack->num_objects) {
 838                 off_t ofs = pack_pos_to_offset(pack, pos);
 839                 if (packed_object_info(the_repository, pack, ofs, &oi) < 0) {
 840                         struct object_id oid;
 841                         nth_packed_object_id(&oid, pack,
 842                                              pack_pos_to_index(pack, pos));
 843                         die(_("unable to get size of %s"), oid_to_hex(&oid));
 844                 }
 845         } else {
 846                 struct eindex *eindex = &bitmap_git->ext_index;
 847                 struct object *obj = eindex->objects[pos - pack->num_objects];
 848                 if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
 849                         die(_("unable to get size of %s"), oid_to_hex(&obj->oid));
 850         }
 851
 852         return size;
 853 }
 854
 855 static void filter_bitmap_blob_limit(struct bitmap_index *bitmap_git,
 856                                      struct object_list *tip_objects,
 857                                      struct bitmap *to_filter,
 858                                      unsigned long limit)
 859 {
 860         struct eindex *eindex = &bitmap_git->ext_index;
 861         struct bitmap *tips;
 862         struct ewah_iterator it;
 863         eword_t mask;
 864         uint32_t i;
 865
 866         tips = find_tip_objects(bitmap_git, tip_objects, OBJ_BLOB);
 867
 868         for (i = 0, init_type_iterator(&it, bitmap_git, OBJ_BLOB);
 869              i < to_filter->word_alloc && ewah_iterator_next(&mask, &it);
 870              i++) {
 871                 eword_t word = to_filter->words[i] & mask;
 872                 unsigned offset;
 873
 874                 for (offset = 0; offset < BITS_IN_EWORD; offset++) {
 875                         uint32_t pos;
 876
 877                         if ((word >> offset) == 0)
 878                                 break;
 879                         offset += ewah_bit_ctz64(word >> offset);
 880                         pos = i * BITS_IN_EWORD + offset;
 881
 882                         if (!bitmap_get(tips, pos) &&
 883                             get_size_by_pos(bitmap_git, pos) >= limit)
 884                                 bitmap_unset(to_filter, pos);
 885                 }
 886         }
 887
 888         for (i = 0; i < eindex->count; i++) {
 889                 uint32_t pos = i + bitmap_git->pack->num_objects;
 890                 if (eindex->objects[i]->type == OBJ_BLOB &&
 891                     bitmap_get(to_filter, pos) &&
 892                     !bitmap_get(tips, pos) &&
 893                     get_size_by_pos(bitmap_git, pos) >= limit)
 894                         bitmap_unset(to_filter, pos);
 895         }
 896
 897         bitmap_free(tips);
 898 }
 899
 900 static void filter_bitmap_tree_depth(struct bitmap_index *bitmap_git,
 901                                      struct object_list *tip_objects,
 902                                      struct bitmap *to_filter,
 903                                      unsigned long limit)
 904 {
 905         if (limit)
 906                 BUG("filter_bitmap_tree_depth given non-zero limit");
 907
 908         filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
 909                                    OBJ_TREE);
 910         filter_bitmap_exclude_type(bitmap_git, tip_objects, to_filter,
 911                                    OBJ_BLOB);
 912 }
 913
 914 static int filter_bitmap(struct bitmap_index *bitmap_git,
 915                          struct object_list *tip_objects,
 916                          struct bitmap *to_filter,
 917                          struct list_objects_filter_options *filter)
 918 {
 919         if (!filter || filter->choice == LOFC_DISABLED)
 920                 return 0;
 921
 922         if (filter->choice == LOFC_BLOB_NONE) {
 923                 if (bitmap_git)
 924                         filter_bitmap_blob_none(bitmap_git, tip_objects,
 925                                                 to_filter);
 926                 return 0;
 927         }
 928
 929         if (filter->choice == LOFC_BLOB_LIMIT) {
 930                 if (bitmap_git)
 931                         filter_bitmap_blob_limit(bitmap_git, tip_objects,
 932                                                  to_filter,
 933                                                  filter->blob_limit_value);
 934                 return 0;
 935         }
 936
 937         if (filter->choice == LOFC_TREE_DEPTH &&
 938             filter->tree_exclude_depth == 0) {
 939                 if (bitmap_git)
 940                         filter_bitmap_tree_depth(bitmap_git, tip_objects,
 941                                                  to_filter,
 942                                                  filter->tree_exclude_depth);
 943                 return 0;
 944         }
 945
 946         /* filter choice not handled */
 947         return -1;
 948 }
 949
 950 static int can_filter_bitmap(struct list_objects_filter_options *filter)
 951 {
 952         return !filter_bitmap(NULL, NULL, NULL, filter);
 953 }
 954
 955 struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs,
 956                                          struct list_objects_filter_options *filter)
 957 {
 958         unsigned int i;
 959
 960         struct object_list *wants = NULL;
 961         struct object_list *haves = NULL;
 962
 963         struct bitmap *wants_bitmap = NULL;
 964         struct bitmap *haves_bitmap = NULL;
 965
 966         struct bitmap_index *bitmap_git;
 967
 968         /*
 969          * We can't do pathspec limiting with bitmaps, because we don't know
 970          * which commits are associated with which object changes (let alone
 971          * even which objects are associated with which paths).
 972          */
 973         if (revs->prune)
 974                 return NULL;
 975
 976         if (!can_filter_bitmap(filter))
 977                 return NULL;
 978
 979         /* try to open a bitmapped pack, but don't parse it yet
 980          * because we may not need to use it */
 981         CALLOC_ARRAY(bitmap_git, 1);
 982         if (open_pack_bitmap(revs->repo, bitmap_git) < 0)
 983                 goto cleanup;
 984
 985         for (i = 0; i < revs->pending.nr; ++i) {
 986                 struct object *object = revs->pending.objects[i].item;
 987
 988                 if (object->type == OBJ_NONE)
 989                         parse_object_or_die(&object->oid, NULL);
 990
 991                 while (object->type == OBJ_TAG) {
 992                         struct tag *tag = (struct tag *) object;
 993
 994                         if (object->flags & UNINTERESTING)
 995                                 object_list_insert(object, &haves);
 996                         else
 997                                 object_list_insert(object, &wants);
 998
 999                         object = parse_object_or_die(get_tagged_oid(tag), NULL);
1000                         object->flags |= (tag->object.flags & UNINTERESTING);
1001                 }
1002
1003                 if (object->flags & UNINTERESTING)
1004                         object_list_insert(object, &haves);
1005                 else
1006                         object_list_insert(object, &wants);
1007         }
1008
1009         /*
1010          * if we have a HAVES list, but none of those haves is contained
1011          * in the packfile that has a bitmap, we don't have anything to
1012          * optimize here
1013          */
1014         if (haves && !in_bitmapped_pack(bitmap_git, haves))
1015                 goto cleanup;
1016
1017         /* if we don't want anything, we're done here */
1018         if (!wants)
1019                 goto cleanup;
1020
1021         /*
1022          * now we're going to use bitmaps, so load the actual bitmap entries
1023          * from disk. this is the point of no return; after this the rev_list
1024          * becomes invalidated and we must perform the revwalk through bitmaps
1025          */
1026         if (load_pack_bitmap(bitmap_git) < 0)
1027                 goto cleanup;
1028
1029         object_array_clear(&revs->pending);
1030
1031         if (haves) {
1032                 revs->ignore_missing_links = 1;
1033                 haves_bitmap = find_objects(bitmap_git, revs, haves, NULL,
1034                                             filter);
1035                 reset_revision_walk();
1036                 revs->ignore_missing_links = 0;
1037
1038                 if (haves_bitmap == NULL)
1039                         BUG("failed to perform bitmap walk");
1040         }
1041
1042         wants_bitmap = find_objects(bitmap_git, revs, wants, haves_bitmap,
1043                                     filter);
1044
1045         if (!wants_bitmap)
1046                 BUG("failed to perform bitmap walk");
1047
1048         if (haves_bitmap)
1049                 bitmap_and_not(wants_bitmap, haves_bitmap);
1050
1051         filter_bitmap(bitmap_git, wants, wants_bitmap, filter);
1052
1053         bitmap_git->result = wants_bitmap;
1054         bitmap_git->haves = haves_bitmap;
1055
1056         object_list_free(&wants);
1057         object_list_free(&haves);
1058
1059         return bitmap_git;
1060
1061 cleanup:
1062         free_bitmap_index(bitmap_git);
1063         object_list_free(&wants);
1064         object_list_free(&haves);
1065         return NULL;
1066 }
1067
1068 static void try_partial_reuse(struct bitmap_index *bitmap_git,
1069                               size_t pos,
1070                               struct bitmap *reuse,
1071                               struct pack_window **w_curs)
1072 {
1073         off_t offset, header;
1074         enum object_type type;
1075         unsigned long size;
1076
1077         if (pos >= bitmap_git->pack->num_objects)
1078                 return; /* not actually in the pack */
1079
1080         offset = header = pack_pos_to_offset(bitmap_git->pack, pos);
1081         type = unpack_object_header(bitmap_git->pack, w_curs, &offset, &size);
1082         if (type < 0)
1083                 return; /* broken packfile, punt */
1084
1085         if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA) {
1086                 off_t base_offset;
1087                 uint32_t base_pos;
1088
1089                 /*
1090                  * Find the position of the base object so we can look it up
1091                  * in our bitmaps. If we can't come up with an offset, or if
1092                  * that offset is not in the revidx, the pack is corrupt.
1093                  * There's nothing we can do, so just punt on this object,
1094                  * and the normal slow path will complain about it in
1095                  * more detail.
1096                  */
1097                 base_offset = get_delta_base(bitmap_git->pack, w_curs,
1098                                              &offset, type, header);
1099                 if (!base_offset)
1100                         return;
1101                 if (offset_to_pack_pos(bitmap_git->pack, base_offset, &base_pos) < 0)
1102                         return;
1103
1104                 /*
1105                  * We assume delta dependencies always point backwards. This
1106                  * lets us do a single pass, and is basically always true
1107                  * due to the way OFS_DELTAs work. You would not typically
1108                  * find REF_DELTA in a bitmapped pack, since we only bitmap
1109                  * packs we write fresh, and OFS_DELTA is the default). But
1110                  * let's double check to make sure the pack wasn't written with
1111                  * odd parameters.
1112                  */
1113                 if (base_pos >= pos)
1114                         return;
1115
1116                 /*
1117                  * And finally, if we're not sending the base as part of our
1118                  * reuse chunk, then don't send this object either. The base
1119                  * would come after us, along with other objects not
1120                  * necessarily in the pack, which means we'd need to convert
1121                  * to REF_DELTA on the fly. Better to just let the normal
1122                  * object_entry code path handle it.
1123                  */
1124                 if (!bitmap_get(reuse, base_pos))
1125                         return;
1126         }
1127
1128         /*
1129          * If we got here, then the object is OK to reuse. Mark it.
1130          */
1131         bitmap_set(reuse, pos);
1132 }
1133
1134 int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
1135                                        struct packed_git **packfile_out,
1136                                        uint32_t *entries,
1137                                        struct bitmap **reuse_out)
1138 {
1139         struct bitmap *result = bitmap_git->result;
1140         struct bitmap *reuse;
1141         struct pack_window *w_curs = NULL;
1142         size_t i = 0;
1143         uint32_t offset;
1144
1145         assert(result);
1146
1147         while (i < result->word_alloc && result->words[i] == (eword_t)~0)
1148                 i++;
1149
1150         /* Don't mark objects not in the packfile */
1151         if (i > bitmap_git->pack->num_objects / BITS_IN_EWORD)
1152                 i = bitmap_git->pack->num_objects / BITS_IN_EWORD;
1153
1154         reuse = bitmap_word_alloc(i);
1155         memset(reuse->words, 0xFF, i * sizeof(eword_t));
1156
1157         for (; i < result->word_alloc; ++i) {
1158                 eword_t word = result->words[i];
1159                 size_t pos = (i * BITS_IN_EWORD);
1160
1161                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
1162                         if ((word >> offset) == 0)
1163                                 break;
1164
1165                         offset += ewah_bit_ctz64(word >> offset);
1166                         try_partial_reuse(bitmap_git, pos + offset, reuse, &w_curs);
1167                 }
1168         }
1169
1170         unuse_pack(&w_curs);
1171
1172         *entries = bitmap_popcount(reuse);
1173         if (!*entries) {
1174                 bitmap_free(reuse);
1175                 return -1;
1176         }
1177
1178         /*
1179          * Drop any reused objects from the result, since they will not
1180          * need to be handled separately.
1181          */
1182         bitmap_and_not(result, reuse);
1183         *packfile_out = bitmap_git->pack;
1184         *reuse_out = reuse;
1185         return 0;
1186 }
1187
1188 int bitmap_walk_contains(struct bitmap_index *bitmap_git,
1189                          struct bitmap *bitmap, const struct object_id *oid)
1190 {
1191         int idx;
1192
1193         if (!bitmap)
1194                 return 0;
1195
1196         idx = bitmap_position(bitmap_git, oid);
1197         return idx >= 0 && bitmap_get(bitmap, idx);
1198 }
1199
1200 void traverse_bitmap_commit_list(struct bitmap_index *bitmap_git,
1201                                  struct rev_info *revs,
1202                                  show_reachable_fn show_reachable)
1203 {
1204         assert(bitmap_git->result);
1205
1206         show_objects_for_type(bitmap_git, OBJ_COMMIT, show_reachable);
1207         if (revs->tree_objects)
1208                 show_objects_for_type(bitmap_git, OBJ_TREE, show_reachable);
1209         if (revs->blob_objects)
1210                 show_objects_for_type(bitmap_git, OBJ_BLOB, show_reachable);
1211         if (revs->tag_objects)
1212                 show_objects_for_type(bitmap_git, OBJ_TAG, show_reachable);
1213
1214         show_extended_objects(bitmap_git, revs, show_reachable);
1215 }
1216
1217 static uint32_t count_object_type(struct bitmap_index *bitmap_git,
1218                                   enum object_type type)
1219 {
1220         struct bitmap *objects = bitmap_git->result;
1221         struct eindex *eindex = &bitmap_git->ext_index;
1222
1223         uint32_t i = 0, count = 0;
1224         struct ewah_iterator it;
1225         eword_t filter;
1226
1227         init_type_iterator(&it, bitmap_git, type);
1228
1229         while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
1230                 eword_t word = objects->words[i++] & filter;
1231                 count += ewah_bit_popcount64(word);
1232         }
1233
1234         for (i = 0; i < eindex->count; ++i) {
1235                 if (eindex->objects[i]->type == type &&
1236                         bitmap_get(objects, bitmap_git->pack->num_objects + i))
1237                         count++;
1238         }
1239
1240         return count;
1241 }
1242
1243 void count_bitmap_commit_list(struct bitmap_index *bitmap_git,
1244                               uint32_t *commits, uint32_t *trees,
1245                               uint32_t *blobs, uint32_t *tags)
1246 {
1247         assert(bitmap_git->result);
1248
1249         if (commits)
1250                 *commits = count_object_type(bitmap_git, OBJ_COMMIT);
1251
1252         if (trees)
1253                 *trees = count_object_type(bitmap_git, OBJ_TREE);
1254
1255         if (blobs)
1256                 *blobs = count_object_type(bitmap_git, OBJ_BLOB);
1257
1258         if (tags)
1259                 *tags = count_object_type(bitmap_git, OBJ_TAG);
1260 }
1261
1262 struct bitmap_test_data {
1263         struct bitmap_index *bitmap_git;
1264         struct bitmap *base;
1265         struct progress *prg;
1266         size_t seen;
1267 };
1268
1269 static void test_show_object(struct object *object, const char *name,
1270                              void *data)
1271 {
1272         struct bitmap_test_data *tdata = data;
1273         int bitmap_pos;
1274
1275         bitmap_pos = bitmap_position(tdata->bitmap_git, &object->oid);
1276         if (bitmap_pos < 0)
1277                 die("Object not in bitmap: %s\n", oid_to_hex(&object->oid));
1278
1279         bitmap_set(tdata->base, bitmap_pos);
1280         display_progress(tdata->prg, ++tdata->seen);
1281 }
1282
1283 static void test_show_commit(struct commit *commit, void *data)
1284 {
1285         struct bitmap_test_data *tdata = data;
1286         int bitmap_pos;
1287
1288         bitmap_pos = bitmap_position(tdata->bitmap_git,
1289                                      &commit->object.oid);
1290         if (bitmap_pos < 0)
1291                 die("Object not in bitmap: %s\n", oid_to_hex(&commit->object.oid));
1292
1293         bitmap_set(tdata->base, bitmap_pos);
1294         display_progress(tdata->prg, ++tdata->seen);
1295 }
1296
1297 void test_bitmap_walk(struct rev_info *revs)
1298 {
1299         struct object *root;
1300         struct bitmap *result = NULL;
1301         size_t result_popcnt;
1302         struct bitmap_test_data tdata;
1303         struct bitmap_index *bitmap_git;
1304         struct ewah_bitmap *bm;
1305
1306         if (!(bitmap_git = prepare_bitmap_git(revs->repo)))
1307                 die("failed to load bitmap indexes");
1308
1309         if (revs->pending.nr != 1)
1310                 die("you must specify exactly one commit to test");
1311
1312         fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
1313                 bitmap_git->version, bitmap_git->entry_count);
1314
1315         root = revs->pending.objects[0].item;
1316         bm = bitmap_for_commit(bitmap_git, (struct commit *)root);
1317
1318         if (bm) {
1319                 fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
1320                         oid_to_hex(&root->oid), (int)bm->bit_size, ewah_checksum(bm));
1321
1322                 result = ewah_to_bitmap(bm);
1323         }
1324
1325         if (result == NULL)
1326                 die("Commit %s doesn't have an indexed bitmap", oid_to_hex(&root->oid));
1327
1328         revs->tag_objects = 1;
1329         revs->tree_objects = 1;
1330         revs->blob_objects = 1;
1331
1332         result_popcnt = bitmap_popcount(result);
1333
1334         if (prepare_revision_walk(revs))
1335                 die("revision walk setup failed");
1336
1337         tdata.bitmap_git = bitmap_git;
1338         tdata.base = bitmap_new();
1339         tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
1340         tdata.seen = 0;
1341
1342         traverse_commit_list(revs, &test_show_commit, &test_show_object, &tdata);
1343
1344         stop_progress(&tdata.prg);
1345
1346         if (bitmap_equals(result, tdata.base))
1347                 fprintf(stderr, "OK!\n");
1348         else
1349                 die("mismatch in bitmap results");
1350
1351         free_bitmap_index(bitmap_git);
1352 }
1353
1354 int rebuild_bitmap(const uint32_t *reposition,
1355                    struct ewah_bitmap *source,
1356                    struct bitmap *dest)
1357 {
1358         uint32_t pos = 0;
1359         struct ewah_iterator it;
1360         eword_t word;
1361
1362         ewah_iterator_init(&it, source);
1363
1364         while (ewah_iterator_next(&word, &it)) {
1365                 uint32_t offset, bit_pos;
1366
1367                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
1368                         if ((word >> offset) == 0)
1369                                 break;
1370
1371                         offset += ewah_bit_ctz64(word >> offset);
1372
1373                         bit_pos = reposition[pos + offset];
1374                         if (bit_pos > 0)
1375                                 bitmap_set(dest, bit_pos - 1);
1376                         else /* can't reuse, we don't have the object */
1377                                 return -1;
1378                 }
1379
1380                 pos += BITS_IN_EWORD;
1381         }
1382         return 0;
1383 }
1384
1385 uint32_t *create_bitmap_mapping(struct bitmap_index *bitmap_git,
1386                                 struct packing_data *mapping)
1387 {
1388         uint32_t i, num_objects;
1389         uint32_t *reposition;
1390
1391         num_objects = bitmap_git->pack->num_objects;
1392         CALLOC_ARRAY(reposition, num_objects);
1393
1394         for (i = 0; i < num_objects; ++i) {
1395                 struct object_id oid;
1396                 struct object_entry *oe;
1397
1398                 nth_packed_object_id(&oid, bitmap_git->pack,
1399                                      pack_pos_to_index(bitmap_git->pack, i));
1400                 oe = packlist_find(mapping, &oid);
1401
1402                 if (oe)
1403                         reposition[i] = oe_in_pack_pos(mapping, oe) + 1;
1404         }
1405
1406         return reposition;
1407 }
1408
1409 void free_bitmap_index(struct bitmap_index *b)
1410 {
1411         if (!b)
1412                 return;
1413
1414         if (b->map)
1415                 munmap(b->map, b->map_size);
1416         ewah_pool_free(b->commits);
1417         ewah_pool_free(b->trees);
1418         ewah_pool_free(b->blobs);
1419         ewah_pool_free(b->tags);
1420         kh_destroy_oid_map(b->bitmaps);
1421         free(b->ext_index.objects);
1422         free(b->ext_index.hashes);
1423         bitmap_free(b->result);
1424         bitmap_free(b->haves);
1425         free(b);
1426 }
1427
1428 int bitmap_has_oid_in_uninteresting(struct bitmap_index *bitmap_git,
1429                                     const struct object_id *oid)
1430 {
1431         return bitmap_git &&
1432                 bitmap_walk_contains(bitmap_git, bitmap_git->haves, oid);
1433 }
1434
1435 static off_t get_disk_usage_for_type(struct bitmap_index *bitmap_git,
1436                                      enum object_type object_type)
1437 {
1438         struct bitmap *result = bitmap_git->result;
1439         struct packed_git *pack = bitmap_git->pack;
1440         off_t total = 0;
1441         struct ewah_iterator it;
1442         eword_t filter;
1443         size_t i;
1444
1445         init_type_iterator(&it, bitmap_git, object_type);
1446         for (i = 0; i < result->word_alloc &&
1447                         ewah_iterator_next(&filter, &it); i++) {
1448                 eword_t word = result->words[i] & filter;
1449                 size_t base = (i * BITS_IN_EWORD);
1450                 unsigned offset;
1451
1452                 if (!word)
1453                         continue;
1454
1455                 for (offset = 0; offset < BITS_IN_EWORD; offset++) {
1456                         size_t pos;
1457
1458                         if ((word >> offset) == 0)
1459                                 break;
1460
1461                         offset += ewah_bit_ctz64(word >> offset);
1462                         pos = base + offset;
1463                         total += pack_pos_to_offset(pack, pos + 1) -
1464                                  pack_pos_to_offset(pack, pos);
1465                 }
1466         }
1467
1468         return total;
1469 }
1470
1471 static off_t get_disk_usage_for_extended(struct bitmap_index *bitmap_git)
1472 {
1473         struct bitmap *result = bitmap_git->result;
1474         struct packed_git *pack = bitmap_git->pack;
1475         struct eindex *eindex = &bitmap_git->ext_index;
1476         off_t total = 0;
1477         struct object_info oi = OBJECT_INFO_INIT;
1478         off_t object_size;
1479         size_t i;
1480
1481         oi.disk_sizep = &object_size;
1482
1483         for (i = 0; i < eindex->count; i++) {
1484                 struct object *obj = eindex->objects[i];
1485
1486                 if (!bitmap_get(result, pack->num_objects + i))
1487                         continue;
1488
1489                 if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
1490                         die(_("unable to get disk usage of %s"),
1491                             oid_to_hex(&obj->oid));
1492
1493                 total += object_size;
1494         }
1495         return total;
1496 }
1497
1498 off_t get_disk_usage_from_bitmap(struct bitmap_index *bitmap_git,
1499                                  struct rev_info *revs)
1500 {
1501         off_t total = 0;
1502
1503         total += get_disk_usage_for_type(bitmap_git, OBJ_COMMIT);
1504         if (revs->tree_objects)
1505                 total += get_disk_usage_for_type(bitmap_git, OBJ_TREE);
1506         if (revs->blob_objects)
1507                 total += get_disk_usage_for_type(bitmap_git, OBJ_BLOB);
1508         if (revs->tag_objects)
1509                 total += get_disk_usage_for_type(bitmap_git, OBJ_TAG);
1510
1511         total += get_disk_usage_for_extended(bitmap_git);
1512
1513         return total;
1514 }