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
  13 /*
  14  * An entry on the bitmap index, representing the bitmap for a given
  15  * commit.
  16  */
  17 struct stored_bitmap {
  18         unsigned char sha1[20];
  19         struct ewah_bitmap *root;
  20         struct stored_bitmap *xor;
  21         int flags;
  22 };
  23
  24 /*
  25  * The currently active bitmap index. By design, repositories only have
  26  * a single bitmap index available (the index for the biggest packfile in
  27  * the repository), since bitmap indexes need full closure.
  28  *
  29  * If there is more than one bitmap index available (e.g. because of alternates),
  30  * the active bitmap index is the largest one.
  31  */
  32 static struct bitmap_index {
  33         /* Packfile to which this bitmap index belongs to */
  34         struct packed_git *pack;
  35
  36         /* reverse index for the packfile */
  37         struct pack_revindex *reverse_index;
  38
  39         /*
  40          * Mark the first `reuse_objects` in the packfile as reused:
  41          * they will be sent as-is without using them for repacking
  42          * calculations
  43          */
  44         uint32_t reuse_objects;
  45
  46         /* mmapped buffer of the whole bitmap index */
  47         unsigned char *map;
  48         size_t map_size; /* size of the mmaped buffer */
  49         size_t map_pos; /* current position when loading the index */
  50
  51         /*
  52          * Type indexes.
  53          *
  54          * Each bitmap marks which objects in the packfile  are of the given
  55          * type. This provides type information when yielding the objects from
  56          * the packfile during a walk, which allows for better delta bases.
  57          */
  58         struct ewah_bitmap *commits;
  59         struct ewah_bitmap *trees;
  60         struct ewah_bitmap *blobs;
  61         struct ewah_bitmap *tags;
  62
  63         /* Map from SHA1 -> `stored_bitmap` for all the bitmapped comits */
  64         khash_sha1 *bitmaps;
  65
  66         /* Number of bitmapped commits */
  67         uint32_t entry_count;
  68
  69         /*
  70          * Extended index.
  71          *
  72          * When trying to perform bitmap operations with objects that are not
  73          * packed in `pack`, these objects are added to this "fake index" and
  74          * are assumed to appear at the end of the packfile for all operations
  75          */
  76         struct eindex {
  77                 struct object **objects;
  78                 uint32_t *hashes;
  79                 uint32_t count, alloc;
  80                 khash_sha1_pos *positions;
  81         } ext_index;
  82
  83         /* Bitmap result of the last performed walk */
  84         struct bitmap *result;
  85
  86         /* Version of the bitmap index */
  87         unsigned int version;
  88
  89         unsigned loaded : 1;
  90
  91 } bitmap_git;
  92
  93 static struct ewah_bitmap *lookup_stored_bitmap(struct stored_bitmap *st)
  94 {
  95         struct ewah_bitmap *parent;
  96         struct ewah_bitmap *composed;
  97
  98         if (st->xor == NULL)
  99                 return st->root;
 100
 101         composed = ewah_pool_new();
 102         parent = lookup_stored_bitmap(st->xor);
 103         ewah_xor(st->root, parent, composed);
 104
 105         ewah_pool_free(st->root);
 106         st->root = composed;
 107         st->xor = NULL;
 108
 109         return composed;
 110 }
 111
 112 /*
 113  * Read a bitmap from the current read position on the mmaped
 114  * index, and increase the read position accordingly
 115  */
 116 static struct ewah_bitmap *read_bitmap_1(struct bitmap_index *index)
 117 {
 118         struct ewah_bitmap *b = ewah_pool_new();
 119
 120         int bitmap_size = ewah_read_mmap(b,
 121                 index->map + index->map_pos,
 122                 index->map_size - index->map_pos);
 123
 124         if (bitmap_size < 0) {
 125                 error("Failed to load bitmap index (corrupted?)");
 126                 ewah_pool_free(b);
 127                 return NULL;
 128         }
 129
 130         index->map_pos += bitmap_size;
 131         return b;
 132 }
 133
 134 static int load_bitmap_header(struct bitmap_index *index)
 135 {
 136         struct bitmap_disk_header *header = (void *)index->map;
 137
 138         if (index->map_size < sizeof(*header) + 20)
 139                 return error("Corrupted bitmap index (missing header data)");
 140
 141         if (memcmp(header->magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE)) != 0)
 142                 return error("Corrupted bitmap index file (wrong header)");
 143
 144         index->version = ntohs(header->version);
 145         if (index->version != 1)
 146                 return error("Unsupported version for bitmap index file (%d)", index->version);
 147
 148         /* Parse known bitmap format options */
 149         {
 150                 uint32_t flags = ntohs(header->options);
 151
 152                 if ((flags & BITMAP_OPT_FULL_DAG) == 0)
 153                         return error("Unsupported options for bitmap index file "
 154                                 "(Git requires BITMAP_OPT_FULL_DAG)");
 155         }
 156
 157         index->entry_count = ntohl(header->entry_count);
 158         index->map_pos += sizeof(*header);
 159         return 0;
 160 }
 161
 162 static struct stored_bitmap *store_bitmap(struct bitmap_index *index,
 163                                           struct ewah_bitmap *root,
 164                                           const unsigned char *sha1,
 165                                           struct stored_bitmap *xor_with,
 166                                           int flags)
 167 {
 168         struct stored_bitmap *stored;
 169         khiter_t hash_pos;
 170         int ret;
 171
 172         stored = xmalloc(sizeof(struct stored_bitmap));
 173         stored->root = root;
 174         stored->xor = xor_with;
 175         stored->flags = flags;
 176         hashcpy(stored->sha1, sha1);
 177
 178         hash_pos = kh_put_sha1(index->bitmaps, stored->sha1, &ret);
 179
 180         /* a 0 return code means the insertion succeeded with no changes,
 181          * because the SHA1 already existed on the map. this is bad, there
 182          * shouldn't be duplicated commits in the index */
 183         if (ret == 0) {
 184                 error("Duplicate entry in bitmap index: %s", sha1_to_hex(sha1));
 185                 return NULL;
 186         }
 187
 188         kh_value(index->bitmaps, hash_pos) = stored;
 189         return stored;
 190 }
 191
 192 static int load_bitmap_entries_v1(struct bitmap_index *index)
 193 {
 194         static const size_t MAX_XOR_OFFSET = 160;
 195
 196         uint32_t i;
 197         struct stored_bitmap **recent_bitmaps;
 198         struct bitmap_disk_entry *entry;
 199
 200         recent_bitmaps = xcalloc(MAX_XOR_OFFSET, sizeof(struct stored_bitmap));
 201
 202         for (i = 0; i < index->entry_count; ++i) {
 203                 int xor_offset, flags;
 204                 struct ewah_bitmap *bitmap = NULL;
 205                 struct stored_bitmap *xor_bitmap = NULL;
 206                 uint32_t commit_idx_pos;
 207                 const unsigned char *sha1;
 208
 209                 entry = (struct bitmap_disk_entry *)(index->map + index->map_pos);
 210                 index->map_pos += sizeof(struct bitmap_disk_entry);
 211
 212                 commit_idx_pos = ntohl(entry->object_pos);
 213                 sha1 = nth_packed_object_sha1(index->pack, commit_idx_pos);
 214
 215                 xor_offset = (int)entry->xor_offset;
 216                 flags = (int)entry->flags;
 217
 218                 bitmap = read_bitmap_1(index);
 219                 if (!bitmap)
 220                         return -1;
 221
 222                 if (xor_offset > MAX_XOR_OFFSET || xor_offset > i)
 223                         return error("Corrupted bitmap pack index");
 224
 225                 if (xor_offset > 0) {
 226                         xor_bitmap = recent_bitmaps[(i - xor_offset) % MAX_XOR_OFFSET];
 227
 228                         if (xor_bitmap == NULL)
 229                                 return error("Invalid XOR offset in bitmap pack index");
 230                 }
 231
 232                 recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
 233                         index, bitmap, sha1, xor_bitmap, flags);
 234         }
 235
 236         return 0;
 237 }
 238
 239 static int open_pack_bitmap_1(struct packed_git *packfile)
 240 {
 241         int fd;
 242         struct stat st;
 243         char *idx_name;
 244
 245         if (open_pack_index(packfile))
 246                 return -1;
 247
 248         idx_name = pack_bitmap_filename(packfile);
 249         fd = git_open_noatime(idx_name);
 250         free(idx_name);
 251
 252         if (fd < 0)
 253                 return -1;
 254
 255         if (fstat(fd, &st)) {
 256                 close(fd);
 257                 return -1;
 258         }
 259
 260         if (bitmap_git.pack) {
 261                 warning("ignoring extra bitmap file: %s", packfile->pack_name);
 262                 close(fd);
 263                 return -1;
 264         }
 265
 266         bitmap_git.pack = packfile;
 267         bitmap_git.map_size = xsize_t(st.st_size);
 268         bitmap_git.map = xmmap(NULL, bitmap_git.map_size, PROT_READ, MAP_PRIVATE, fd, 0);
 269         bitmap_git.map_pos = 0;
 270         close(fd);
 271
 272         if (load_bitmap_header(&bitmap_git) < 0) {
 273                 munmap(bitmap_git.map, bitmap_git.map_size);
 274                 bitmap_git.map = NULL;
 275                 bitmap_git.map_size = 0;
 276                 return -1;
 277         }
 278
 279         return 0;
 280 }
 281
 282 static int load_pack_bitmap(void)
 283 {
 284         assert(bitmap_git.map && !bitmap_git.loaded);
 285
 286         bitmap_git.bitmaps = kh_init_sha1();
 287         bitmap_git.ext_index.positions = kh_init_sha1_pos();
 288         bitmap_git.reverse_index = revindex_for_pack(bitmap_git.pack);
 289
 290         if (!(bitmap_git.commits = read_bitmap_1(&bitmap_git)) ||
 291                 !(bitmap_git.trees = read_bitmap_1(&bitmap_git)) ||
 292                 !(bitmap_git.blobs = read_bitmap_1(&bitmap_git)) ||
 293                 !(bitmap_git.tags = read_bitmap_1(&bitmap_git)))
 294                 goto failed;
 295
 296         if (load_bitmap_entries_v1(&bitmap_git) < 0)
 297                 goto failed;
 298
 299         bitmap_git.loaded = 1;
 300         return 0;
 301
 302 failed:
 303         munmap(bitmap_git.map, bitmap_git.map_size);
 304         bitmap_git.map = NULL;
 305         bitmap_git.map_size = 0;
 306         return -1;
 307 }
 308
 309 char *pack_bitmap_filename(struct packed_git *p)
 310 {
 311         char *idx_name;
 312         int len;
 313
 314         len = strlen(p->pack_name) - strlen(".pack");
 315         idx_name = xmalloc(len + strlen(".bitmap") + 1);
 316
 317         memcpy(idx_name, p->pack_name, len);
 318         memcpy(idx_name + len, ".bitmap", strlen(".bitmap") + 1);
 319
 320         return idx_name;
 321 }
 322
 323 static int open_pack_bitmap(void)
 324 {
 325         struct packed_git *p;
 326         int ret = -1;
 327
 328         assert(!bitmap_git.map && !bitmap_git.loaded);
 329
 330         prepare_packed_git();
 331         for (p = packed_git; p; p = p->next) {
 332                 if (open_pack_bitmap_1(p) == 0)
 333                         ret = 0;
 334         }
 335
 336         return ret;
 337 }
 338
 339 int prepare_bitmap_git(void)
 340 {
 341         if (bitmap_git.loaded)
 342                 return 0;
 343
 344         if (!open_pack_bitmap())
 345                 return load_pack_bitmap();
 346
 347         return -1;
 348 }
 349
 350 struct include_data {
 351         struct bitmap *base;
 352         struct bitmap *seen;
 353 };
 354
 355 static inline int bitmap_position_extended(const unsigned char *sha1)
 356 {
 357         khash_sha1_pos *positions = bitmap_git.ext_index.positions;
 358         khiter_t pos = kh_get_sha1_pos(positions, sha1);
 359
 360         if (pos < kh_end(positions)) {
 361                 int bitmap_pos = kh_value(positions, pos);
 362                 return bitmap_pos + bitmap_git.pack->num_objects;
 363         }
 364
 365         return -1;
 366 }
 367
 368 static inline int bitmap_position_packfile(const unsigned char *sha1)
 369 {
 370         off_t offset = find_pack_entry_one(sha1, bitmap_git.pack);
 371         if (!offset)
 372                 return -1;
 373
 374         return find_revindex_position(bitmap_git.reverse_index, offset);
 375 }
 376
 377 static int bitmap_position(const unsigned char *sha1)
 378 {
 379         int pos = bitmap_position_packfile(sha1);
 380         return (pos >= 0) ? pos : bitmap_position_extended(sha1);
 381 }
 382
 383 static int ext_index_add_object(struct object *object, const char *name)
 384 {
 385         struct eindex *eindex = &bitmap_git.ext_index;
 386
 387         khiter_t hash_pos;
 388         int hash_ret;
 389         int bitmap_pos;
 390
 391         hash_pos = kh_put_sha1_pos(eindex->positions, object->sha1, &hash_ret);
 392         if (hash_ret > 0) {
 393                 if (eindex->count >= eindex->alloc) {
 394                         eindex->alloc = (eindex->alloc + 16) * 3 / 2;
 395                         eindex->objects = xrealloc(eindex->objects,
 396                                 eindex->alloc * sizeof(struct object *));
 397                         eindex->hashes = xrealloc(eindex->hashes,
 398                                 eindex->alloc * sizeof(uint32_t));
 399                 }
 400
 401                 bitmap_pos = eindex->count;
 402                 eindex->objects[eindex->count] = object;
 403                 eindex->hashes[eindex->count] = pack_name_hash(name);
 404                 kh_value(eindex->positions, hash_pos) = bitmap_pos;
 405                 eindex->count++;
 406         } else {
 407                 bitmap_pos = kh_value(eindex->positions, hash_pos);
 408         }
 409
 410         return bitmap_pos + bitmap_git.pack->num_objects;
 411 }
 412
 413 static void show_object(struct object *object, const struct name_path *path,
 414                         const char *last, void *data)
 415 {
 416         struct bitmap *base = data;
 417         int bitmap_pos;
 418
 419         bitmap_pos = bitmap_position(object->sha1);
 420
 421         if (bitmap_pos < 0) {
 422                 char *name = path_name(path, last);
 423                 bitmap_pos = ext_index_add_object(object, name);
 424                 free(name);
 425         }
 426
 427         bitmap_set(base, bitmap_pos);
 428 }
 429
 430 static void show_commit(struct commit *commit, void *data)
 431 {
 432 }
 433
 434 static int add_to_include_set(struct include_data *data,
 435                               const unsigned char *sha1,
 436                               int bitmap_pos)
 437 {
 438         khiter_t hash_pos;
 439
 440         if (data->seen && bitmap_get(data->seen, bitmap_pos))
 441                 return 0;
 442
 443         if (bitmap_get(data->base, bitmap_pos))
 444                 return 0;
 445
 446         hash_pos = kh_get_sha1(bitmap_git.bitmaps, sha1);
 447         if (hash_pos < kh_end(bitmap_git.bitmaps)) {
 448                 struct stored_bitmap *st = kh_value(bitmap_git.bitmaps, hash_pos);
 449                 bitmap_or_ewah(data->base, lookup_stored_bitmap(st));
 450                 return 0;
 451         }
 452
 453         bitmap_set(data->base, bitmap_pos);
 454         return 1;
 455 }
 456
 457 static int should_include(struct commit *commit, void *_data)
 458 {
 459         struct include_data *data = _data;
 460         int bitmap_pos;
 461
 462         bitmap_pos = bitmap_position(commit->object.sha1);
 463         if (bitmap_pos < 0)
 464                 bitmap_pos = ext_index_add_object((struct object *)commit, NULL);
 465
 466         if (!add_to_include_set(data, commit->object.sha1, bitmap_pos)) {
 467                 struct commit_list *parent = commit->parents;
 468
 469                 while (parent) {
 470                         parent->item->object.flags |= SEEN;
 471                         parent = parent->next;
 472                 }
 473
 474                 return 0;
 475         }
 476
 477         return 1;
 478 }
 479
 480 static struct bitmap *find_objects(struct rev_info *revs,
 481                                    struct object_list *roots,
 482                                    struct bitmap *seen)
 483 {
 484         struct bitmap *base = NULL;
 485         int needs_walk = 0;
 486
 487         struct object_list *not_mapped = NULL;
 488
 489         /*
 490          * Go through all the roots for the walk. The ones that have bitmaps
 491          * on the bitmap index will be `or`ed together to form an initial
 492          * global reachability analysis.
 493          *
 494          * The ones without bitmaps in the index will be stored in the
 495          * `not_mapped_list` for further processing.
 496          */
 497         while (roots) {
 498                 struct object *object = roots->item;
 499                 roots = roots->next;
 500
 501                 if (object->type == OBJ_COMMIT) {
 502                         khiter_t pos = kh_get_sha1(bitmap_git.bitmaps, object->sha1);
 503
 504                         if (pos < kh_end(bitmap_git.bitmaps)) {
 505                                 struct stored_bitmap *st = kh_value(bitmap_git.bitmaps, pos);
 506                                 struct ewah_bitmap *or_with = lookup_stored_bitmap(st);
 507
 508                                 if (base == NULL)
 509                                         base = ewah_to_bitmap(or_with);
 510                                 else
 511                                         bitmap_or_ewah(base, or_with);
 512
 513                                 object->flags |= SEEN;
 514                                 continue;
 515                         }
 516                 }
 517
 518                 object_list_insert(object, &not_mapped);
 519         }
 520
 521         /*
 522          * Best case scenario: We found bitmaps for all the roots,
 523          * so the resulting `or` bitmap has the full reachability analysis
 524          */
 525         if (not_mapped == NULL)
 526                 return base;
 527
 528         roots = not_mapped;
 529
 530         /*
 531          * Let's iterate through all the roots that don't have bitmaps to
 532          * check if we can determine them to be reachable from the existing
 533          * global bitmap.
 534          *
 535          * If we cannot find them in the existing global bitmap, we'll need
 536          * to push them to an actual walk and run it until we can confirm
 537          * they are reachable
 538          */
 539         while (roots) {
 540                 struct object *object = roots->item;
 541                 int pos;
 542
 543                 roots = roots->next;
 544                 pos = bitmap_position(object->sha1);
 545
 546                 if (pos < 0 || base == NULL || !bitmap_get(base, pos)) {
 547                         object->flags &= ~UNINTERESTING;
 548                         add_pending_object(revs, object, "");
 549                         needs_walk = 1;
 550                 } else {
 551                         object->flags |= SEEN;
 552                 }
 553         }
 554
 555         if (needs_walk) {
 556                 struct include_data incdata;
 557
 558                 if (base == NULL)
 559                         base = bitmap_new();
 560
 561                 incdata.base = base;
 562                 incdata.seen = seen;
 563
 564                 revs->include_check = should_include;
 565                 revs->include_check_data = &incdata;
 566
 567                 if (prepare_revision_walk(revs))
 568                         die("revision walk setup failed");
 569
 570                 traverse_commit_list(revs, show_commit, show_object, base);
 571         }
 572
 573         return base;
 574 }
 575
 576 static void show_extended_objects(struct bitmap *objects,
 577                                   show_reachable_fn show_reach)
 578 {
 579         struct eindex *eindex = &bitmap_git.ext_index;
 580         uint32_t i;
 581
 582         for (i = 0; i < eindex->count; ++i) {
 583                 struct object *obj;
 584
 585                 if (!bitmap_get(objects, bitmap_git.pack->num_objects + i))
 586                         continue;
 587
 588                 obj = eindex->objects[i];
 589                 show_reach(obj->sha1, obj->type, 0, eindex->hashes[i], NULL, 0);
 590         }
 591 }
 592
 593 static void show_objects_for_type(
 594         struct bitmap *objects,
 595         struct ewah_bitmap *type_filter,
 596         enum object_type object_type,
 597         show_reachable_fn show_reach)
 598 {
 599         size_t pos = 0, i = 0;
 600         uint32_t offset;
 601
 602         struct ewah_iterator it;
 603         eword_t filter;
 604
 605         if (bitmap_git.reuse_objects == bitmap_git.pack->num_objects)
 606                 return;
 607
 608         ewah_iterator_init(&it, type_filter);
 609
 610         while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
 611                 eword_t word = objects->words[i] & filter;
 612
 613                 for (offset = 0; offset < BITS_IN_WORD; ++offset) {
 614                         const unsigned char *sha1;
 615                         struct revindex_entry *entry;
 616                         uint32_t hash = 0;
 617
 618                         if ((word >> offset) == 0)
 619                                 break;
 620
 621                         offset += ewah_bit_ctz64(word >> offset);
 622
 623                         if (pos + offset < bitmap_git.reuse_objects)
 624                                 continue;
 625
 626                         entry = &bitmap_git.reverse_index->revindex[pos + offset];
 627                         sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
 628
 629                         show_reach(sha1, object_type, 0, hash, bitmap_git.pack, entry->offset);
 630                 }
 631
 632                 pos += BITS_IN_WORD;
 633                 i++;
 634         }
 635 }
 636
 637 static int in_bitmapped_pack(struct object_list *roots)
 638 {
 639         while (roots) {
 640                 struct object *object = roots->item;
 641                 roots = roots->next;
 642
 643                 if (find_pack_entry_one(object->sha1, bitmap_git.pack) > 0)
 644                         return 1;
 645         }
 646
 647         return 0;
 648 }
 649
 650 int prepare_bitmap_walk(struct rev_info *revs)
 651 {
 652         unsigned int i;
 653         unsigned int pending_nr = revs->pending.nr;
 654         struct object_array_entry *pending_e = revs->pending.objects;
 655
 656         struct object_list *wants = NULL;
 657         struct object_list *haves = NULL;
 658
 659         struct bitmap *wants_bitmap = NULL;
 660         struct bitmap *haves_bitmap = NULL;
 661
 662         if (!bitmap_git.loaded) {
 663                 /* try to open a bitmapped pack, but don't parse it yet
 664                  * because we may not need to use it */
 665                 if (open_pack_bitmap() < 0)
 666                         return -1;
 667         }
 668
 669         for (i = 0; i < pending_nr; ++i) {
 670                 struct object *object = pending_e[i].item;
 671
 672                 if (object->type == OBJ_NONE)
 673                         parse_object_or_die(object->sha1, NULL);
 674
 675                 while (object->type == OBJ_TAG) {
 676                         struct tag *tag = (struct tag *) object;
 677
 678                         if (object->flags & UNINTERESTING)
 679                                 object_list_insert(object, &haves);
 680                         else
 681                                 object_list_insert(object, &wants);
 682
 683                         if (!tag->tagged)
 684                                 die("bad tag");
 685                         object = parse_object_or_die(tag->tagged->sha1, NULL);
 686                 }
 687
 688                 if (object->flags & UNINTERESTING)
 689                         object_list_insert(object, &haves);
 690                 else
 691                         object_list_insert(object, &wants);
 692         }
 693
 694         /*
 695          * if we have a HAVES list, but none of those haves is contained
 696          * in the packfile that has a bitmap, we don't have anything to
 697          * optimize here
 698          */
 699         if (haves && !in_bitmapped_pack(haves))
 700                 return -1;
 701
 702         /* if we don't want anything, we're done here */
 703         if (!wants)
 704                 return -1;
 705
 706         /*
 707          * now we're going to use bitmaps, so load the actual bitmap entries
 708          * from disk. this is the point of no return; after this the rev_list
 709          * becomes invalidated and we must perform the revwalk through bitmaps
 710          */
 711         if (!bitmap_git.loaded && load_pack_bitmap() < 0)
 712                 return -1;
 713
 714         revs->pending.nr = 0;
 715         revs->pending.alloc = 0;
 716         revs->pending.objects = NULL;
 717
 718         if (haves) {
 719                 haves_bitmap = find_objects(revs, haves, NULL);
 720                 reset_revision_walk();
 721
 722                 if (haves_bitmap == NULL)
 723                         die("BUG: failed to perform bitmap walk");
 724         }
 725
 726         wants_bitmap = find_objects(revs, wants, haves_bitmap);
 727
 728         if (!wants_bitmap)
 729                 die("BUG: failed to perform bitmap walk");
 730
 731         if (haves_bitmap)
 732                 bitmap_and_not(wants_bitmap, haves_bitmap);
 733
 734         bitmap_git.result = wants_bitmap;
 735
 736         bitmap_free(haves_bitmap);
 737         return 0;
 738 }
 739
 740 int reuse_partial_packfile_from_bitmap(struct packed_git **packfile,
 741                                        uint32_t *entries,
 742                                        off_t *up_to)
 743 {
 744         /*
 745          * Reuse the packfile content if we need more than
 746          * 90% of its objects
 747          */
 748         static const double REUSE_PERCENT = 0.9;
 749
 750         struct bitmap *result = bitmap_git.result;
 751         uint32_t reuse_threshold;
 752         uint32_t i, reuse_objects = 0;
 753
 754         assert(result);
 755
 756         for (i = 0; i < result->word_alloc; ++i) {
 757                 if (result->words[i] != (eword_t)~0) {
 758                         reuse_objects += ewah_bit_ctz64(~result->words[i]);
 759                         break;
 760                 }
 761
 762                 reuse_objects += BITS_IN_WORD;
 763         }
 764
 765 #ifdef GIT_BITMAP_DEBUG
 766         {
 767                 const unsigned char *sha1;
 768                 struct revindex_entry *entry;
 769
 770                 entry = &bitmap_git.reverse_index->revindex[reuse_objects];
 771                 sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
 772
 773                 fprintf(stderr, "Failed to reuse at %d (%016llx)\n",
 774                         reuse_objects, result->words[i]);
 775                 fprintf(stderr, " %s\n", sha1_to_hex(sha1));
 776         }
 777 #endif
 778
 779         if (!reuse_objects)
 780                 return -1;
 781
 782         if (reuse_objects >= bitmap_git.pack->num_objects) {
 783                 bitmap_git.reuse_objects = *entries = bitmap_git.pack->num_objects;
 784                 *up_to = -1; /* reuse the full pack */
 785                 *packfile = bitmap_git.pack;
 786                 return 0;
 787         }
 788
 789         reuse_threshold = bitmap_popcount(bitmap_git.result) * REUSE_PERCENT;
 790
 791         if (reuse_objects < reuse_threshold)
 792                 return -1;
 793
 794         bitmap_git.reuse_objects = *entries = reuse_objects;
 795         *up_to = bitmap_git.reverse_index->revindex[reuse_objects].offset;
 796         *packfile = bitmap_git.pack;
 797
 798         return 0;
 799 }
 800
 801 void traverse_bitmap_commit_list(show_reachable_fn show_reachable)
 802 {
 803         assert(bitmap_git.result);
 804
 805         show_objects_for_type(bitmap_git.result, bitmap_git.commits,
 806                 OBJ_COMMIT, show_reachable);
 807         show_objects_for_type(bitmap_git.result, bitmap_git.trees,
 808                 OBJ_TREE, show_reachable);
 809         show_objects_for_type(bitmap_git.result, bitmap_git.blobs,
 810                 OBJ_BLOB, show_reachable);
 811         show_objects_for_type(bitmap_git.result, bitmap_git.tags,
 812                 OBJ_TAG, show_reachable);
 813
 814         show_extended_objects(bitmap_git.result, show_reachable);
 815
 816         bitmap_free(bitmap_git.result);
 817         bitmap_git.result = NULL;
 818 }
 819
 820 static uint32_t count_object_type(struct bitmap *objects,
 821                                   enum object_type type)
 822 {
 823         struct eindex *eindex = &bitmap_git.ext_index;
 824
 825         uint32_t i = 0, count = 0;
 826         struct ewah_iterator it;
 827         eword_t filter;
 828
 829         switch (type) {
 830         case OBJ_COMMIT:
 831                 ewah_iterator_init(&it, bitmap_git.commits);
 832                 break;
 833
 834         case OBJ_TREE:
 835                 ewah_iterator_init(&it, bitmap_git.trees);
 836                 break;
 837
 838         case OBJ_BLOB:
 839                 ewah_iterator_init(&it, bitmap_git.blobs);
 840                 break;
 841
 842         case OBJ_TAG:
 843                 ewah_iterator_init(&it, bitmap_git.tags);
 844                 break;
 845
 846         default:
 847                 return 0;
 848         }
 849
 850         while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
 851                 eword_t word = objects->words[i++] & filter;
 852                 count += ewah_bit_popcount64(word);
 853         }
 854
 855         for (i = 0; i < eindex->count; ++i) {
 856                 if (eindex->objects[i]->type == type &&
 857                         bitmap_get(objects, bitmap_git.pack->num_objects + i))
 858                         count++;
 859         }
 860
 861         return count;
 862 }
 863
 864 void count_bitmap_commit_list(uint32_t *commits, uint32_t *trees,
 865                               uint32_t *blobs, uint32_t *tags)
 866 {
 867         assert(bitmap_git.result);
 868
 869         if (commits)
 870                 *commits = count_object_type(bitmap_git.result, OBJ_COMMIT);
 871
 872         if (trees)
 873                 *trees = count_object_type(bitmap_git.result, OBJ_TREE);
 874
 875         if (blobs)
 876                 *blobs = count_object_type(bitmap_git.result, OBJ_BLOB);
 877
 878         if (tags)
 879                 *tags = count_object_type(bitmap_git.result, OBJ_TAG);
 880 }
 881
 882 struct bitmap_test_data {
 883         struct bitmap *base;
 884         struct progress *prg;
 885         size_t seen;
 886 };
 887
 888 static void test_show_object(struct object *object,
 889                              const struct name_path *path,
 890                              const char *last, void *data)
 891 {
 892         struct bitmap_test_data *tdata = data;
 893         int bitmap_pos;
 894
 895         bitmap_pos = bitmap_position(object->sha1);
 896         if (bitmap_pos < 0)
 897                 die("Object not in bitmap: %s\n", sha1_to_hex(object->sha1));
 898
 899         bitmap_set(tdata->base, bitmap_pos);
 900         display_progress(tdata->prg, ++tdata->seen);
 901 }
 902
 903 static void test_show_commit(struct commit *commit, void *data)
 904 {
 905         struct bitmap_test_data *tdata = data;
 906         int bitmap_pos;
 907
 908         bitmap_pos = bitmap_position(commit->object.sha1);
 909         if (bitmap_pos < 0)
 910                 die("Object not in bitmap: %s\n", sha1_to_hex(commit->object.sha1));
 911
 912         bitmap_set(tdata->base, bitmap_pos);
 913         display_progress(tdata->prg, ++tdata->seen);
 914 }
 915
 916 void test_bitmap_walk(struct rev_info *revs)
 917 {
 918         struct object *root;
 919         struct bitmap *result = NULL;
 920         khiter_t pos;
 921         size_t result_popcnt;
 922         struct bitmap_test_data tdata;
 923
 924         if (prepare_bitmap_git())
 925                 die("failed to load bitmap indexes");
 926
 927         if (revs->pending.nr != 1)
 928                 die("you must specify exactly one commit to test");
 929
 930         fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
 931                 bitmap_git.version, bitmap_git.entry_count);
 932
 933         root = revs->pending.objects[0].item;
 934         pos = kh_get_sha1(bitmap_git.bitmaps, root->sha1);
 935
 936         if (pos < kh_end(bitmap_git.bitmaps)) {
 937                 struct stored_bitmap *st = kh_value(bitmap_git.bitmaps, pos);
 938                 struct ewah_bitmap *bm = lookup_stored_bitmap(st);
 939
 940                 fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
 941                         sha1_to_hex(root->sha1), (int)bm->bit_size, ewah_checksum(bm));
 942
 943                 result = ewah_to_bitmap(bm);
 944         }
 945
 946         if (result == NULL)
 947                 die("Commit %s doesn't have an indexed bitmap", sha1_to_hex(root->sha1));
 948
 949         revs->tag_objects = 1;
 950         revs->tree_objects = 1;
 951         revs->blob_objects = 1;
 952
 953         result_popcnt = bitmap_popcount(result);
 954
 955         if (prepare_revision_walk(revs))
 956                 die("revision walk setup failed");
 957
 958         tdata.base = bitmap_new();
 959         tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
 960         tdata.seen = 0;
 961
 962         traverse_commit_list(revs, &test_show_commit, &test_show_object, &tdata);
 963
 964         stop_progress(&tdata.prg);
 965
 966         if (bitmap_equals(result, tdata.base))
 967                 fprintf(stderr, "OK!\n");
 968         else
 969                 fprintf(stderr, "Mismatch!\n");
 970 }