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
  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 commits */
  64         khash_sha1 *bitmaps;
  65
  66         /* Number of bitmapped commits */
  67         uint32_t entry_count;
  68
  69         /* Name-hash cache (or NULL if not present). */
  70         uint32_t *hashes;
  71
  72         /*
  73          * Extended index.
  74          *
  75          * When trying to perform bitmap operations with objects that are not
  76          * packed in `pack`, these objects are added to this "fake index" and
  77          * are assumed to appear at the end of the packfile for all operations
  78          */
  79         struct eindex {
  80                 struct object **objects;
  81                 uint32_t *hashes;
  82                 uint32_t count, alloc;
  83                 khash_sha1_pos *positions;
  84         } ext_index;
  85
  86         /* Bitmap result of the last performed walk */
  87         struct bitmap *result;
  88
  89         /* Version of the bitmap index */
  90         unsigned int version;
  91
  92         unsigned loaded : 1;
  93
  94 } bitmap_git;
  95
  96 static struct ewah_bitmap *lookup_stored_bitmap(struct stored_bitmap *st)
  97 {
  98         struct ewah_bitmap *parent;
  99         struct ewah_bitmap *composed;
 100
 101         if (st->xor == NULL)
 102                 return st->root;
 103
 104         composed = ewah_pool_new();
 105         parent = lookup_stored_bitmap(st->xor);
 106         ewah_xor(st->root, parent, composed);
 107
 108         ewah_pool_free(st->root);
 109         st->root = composed;
 110         st->xor = NULL;
 111
 112         return composed;
 113 }
 114
 115 /*
 116  * Read a bitmap from the current read position on the mmaped
 117  * index, and increase the read position accordingly
 118  */
 119 static struct ewah_bitmap *read_bitmap_1(struct bitmap_index *index)
 120 {
 121         struct ewah_bitmap *b = ewah_pool_new();
 122
 123         int bitmap_size = ewah_read_mmap(b,
 124                 index->map + index->map_pos,
 125                 index->map_size - index->map_pos);
 126
 127         if (bitmap_size < 0) {
 128                 error("Failed to load bitmap index (corrupted?)");
 129                 ewah_pool_free(b);
 130                 return NULL;
 131         }
 132
 133         index->map_pos += bitmap_size;
 134         return b;
 135 }
 136
 137 static int load_bitmap_header(struct bitmap_index *index)
 138 {
 139         struct bitmap_disk_header *header = (void *)index->map;
 140
 141         if (index->map_size < sizeof(*header) + 20)
 142                 return error("Corrupted bitmap index (missing header data)");
 143
 144         if (memcmp(header->magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE)) != 0)
 145                 return error("Corrupted bitmap index file (wrong header)");
 146
 147         index->version = ntohs(header->version);
 148         if (index->version != 1)
 149                 return error("Unsupported version for bitmap index file (%d)", index->version);
 150
 151         /* Parse known bitmap format options */
 152         {
 153                 uint32_t flags = ntohs(header->options);
 154
 155                 if ((flags & BITMAP_OPT_FULL_DAG) == 0)
 156                         return error("Unsupported options for bitmap index file "
 157                                 "(Git requires BITMAP_OPT_FULL_DAG)");
 158
 159                 if (flags & BITMAP_OPT_HASH_CACHE) {
 160                         unsigned char *end = index->map + index->map_size - 20;
 161                         index->hashes = ((uint32_t *)end) - index->pack->num_objects;
 162                 }
 163         }
 164
 165         index->entry_count = ntohl(header->entry_count);
 166         index->map_pos += sizeof(*header);
 167         return 0;
 168 }
 169
 170 static struct stored_bitmap *store_bitmap(struct bitmap_index *index,
 171                                           struct ewah_bitmap *root,
 172                                           const unsigned char *sha1,
 173                                           struct stored_bitmap *xor_with,
 174                                           int flags)
 175 {
 176         struct stored_bitmap *stored;
 177         khiter_t hash_pos;
 178         int ret;
 179
 180         stored = xmalloc(sizeof(struct stored_bitmap));
 181         stored->root = root;
 182         stored->xor = xor_with;
 183         stored->flags = flags;
 184         hashcpy(stored->sha1, sha1);
 185
 186         hash_pos = kh_put_sha1(index->bitmaps, stored->sha1, &ret);
 187
 188         /* a 0 return code means the insertion succeeded with no changes,
 189          * because the SHA1 already existed on the map. this is bad, there
 190          * shouldn't be duplicated commits in the index */
 191         if (ret == 0) {
 192                 error("Duplicate entry in bitmap index: %s", sha1_to_hex(sha1));
 193                 return NULL;
 194         }
 195
 196         kh_value(index->bitmaps, hash_pos) = stored;
 197         return stored;
 198 }
 199
 200 static inline uint32_t read_be32(const unsigned char *buffer, size_t *pos)
 201 {
 202         uint32_t result = get_be32(buffer + *pos);
 203         (*pos) += sizeof(result);
 204         return result;
 205 }
 206
 207 static inline uint8_t read_u8(const unsigned char *buffer, size_t *pos)
 208 {
 209         return buffer[(*pos)++];
 210 }
 211
 212 #define MAX_XOR_OFFSET 160
 213
 214 static int load_bitmap_entries_v1(struct bitmap_index *index)
 215 {
 216         uint32_t i;
 217         struct stored_bitmap *recent_bitmaps[MAX_XOR_OFFSET] = { NULL };
 218
 219         for (i = 0; i < index->entry_count; ++i) {
 220                 int xor_offset, flags;
 221                 struct ewah_bitmap *bitmap = NULL;
 222                 struct stored_bitmap *xor_bitmap = NULL;
 223                 uint32_t commit_idx_pos;
 224                 const unsigned char *sha1;
 225
 226                 commit_idx_pos = read_be32(index->map, &index->map_pos);
 227                 xor_offset = read_u8(index->map, &index->map_pos);
 228                 flags = read_u8(index->map, &index->map_pos);
 229
 230                 sha1 = nth_packed_object_sha1(index->pack, commit_idx_pos);
 231
 232                 bitmap = read_bitmap_1(index);
 233                 if (!bitmap)
 234                         return -1;
 235
 236                 if (xor_offset > MAX_XOR_OFFSET || xor_offset > i)
 237                         return error("Corrupted bitmap pack index");
 238
 239                 if (xor_offset > 0) {
 240                         xor_bitmap = recent_bitmaps[(i - xor_offset) % MAX_XOR_OFFSET];
 241
 242                         if (xor_bitmap == NULL)
 243                                 return error("Invalid XOR offset in bitmap pack index");
 244                 }
 245
 246                 recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
 247                         index, bitmap, sha1, xor_bitmap, flags);
 248         }
 249
 250         return 0;
 251 }
 252
 253 static char *pack_bitmap_filename(struct packed_git *p)
 254 {
 255         char *idx_name;
 256         int len;
 257
 258         len = strlen(p->pack_name) - strlen(".pack");
 259         idx_name = xmalloc(len + strlen(".bitmap") + 1);
 260
 261         memcpy(idx_name, p->pack_name, len);
 262         memcpy(idx_name + len, ".bitmap", strlen(".bitmap") + 1);
 263
 264         return idx_name;
 265 }
 266
 267 static int open_pack_bitmap_1(struct packed_git *packfile)
 268 {
 269         int fd;
 270         struct stat st;
 271         char *idx_name;
 272
 273         if (open_pack_index(packfile))
 274                 return -1;
 275
 276         idx_name = pack_bitmap_filename(packfile);
 277         fd = git_open_noatime(idx_name);
 278         free(idx_name);
 279
 280         if (fd < 0)
 281                 return -1;
 282
 283         if (fstat(fd, &st)) {
 284                 close(fd);
 285                 return -1;
 286         }
 287
 288         if (bitmap_git.pack) {
 289                 warning("ignoring extra bitmap file: %s", packfile->pack_name);
 290                 close(fd);
 291                 return -1;
 292         }
 293
 294         bitmap_git.pack = packfile;
 295         bitmap_git.map_size = xsize_t(st.st_size);
 296         bitmap_git.map = xmmap(NULL, bitmap_git.map_size, PROT_READ, MAP_PRIVATE, fd, 0);
 297         bitmap_git.map_pos = 0;
 298         close(fd);
 299
 300         if (load_bitmap_header(&bitmap_git) < 0) {
 301                 munmap(bitmap_git.map, bitmap_git.map_size);
 302                 bitmap_git.map = NULL;
 303                 bitmap_git.map_size = 0;
 304                 return -1;
 305         }
 306
 307         return 0;
 308 }
 309
 310 static int load_pack_bitmap(void)
 311 {
 312         assert(bitmap_git.map && !bitmap_git.loaded);
 313
 314         bitmap_git.bitmaps = kh_init_sha1();
 315         bitmap_git.ext_index.positions = kh_init_sha1_pos();
 316         bitmap_git.reverse_index = revindex_for_pack(bitmap_git.pack);
 317
 318         if (!(bitmap_git.commits = read_bitmap_1(&bitmap_git)) ||
 319                 !(bitmap_git.trees = read_bitmap_1(&bitmap_git)) ||
 320                 !(bitmap_git.blobs = read_bitmap_1(&bitmap_git)) ||
 321                 !(bitmap_git.tags = read_bitmap_1(&bitmap_git)))
 322                 goto failed;
 323
 324         if (load_bitmap_entries_v1(&bitmap_git) < 0)
 325                 goto failed;
 326
 327         bitmap_git.loaded = 1;
 328         return 0;
 329
 330 failed:
 331         munmap(bitmap_git.map, bitmap_git.map_size);
 332         bitmap_git.map = NULL;
 333         bitmap_git.map_size = 0;
 334         return -1;
 335 }
 336
 337 static int open_pack_bitmap(void)
 338 {
 339         struct packed_git *p;
 340         int ret = -1;
 341
 342         assert(!bitmap_git.map && !bitmap_git.loaded);
 343
 344         prepare_packed_git();
 345         for (p = packed_git; p; p = p->next) {
 346                 if (open_pack_bitmap_1(p) == 0)
 347                         ret = 0;
 348         }
 349
 350         return ret;
 351 }
 352
 353 int prepare_bitmap_git(void)
 354 {
 355         if (bitmap_git.loaded)
 356                 return 0;
 357
 358         if (!open_pack_bitmap())
 359                 return load_pack_bitmap();
 360
 361         return -1;
 362 }
 363
 364 struct include_data {
 365         struct bitmap *base;
 366         struct bitmap *seen;
 367 };
 368
 369 static inline int bitmap_position_extended(const unsigned char *sha1)
 370 {
 371         khash_sha1_pos *positions = bitmap_git.ext_index.positions;
 372         khiter_t pos = kh_get_sha1_pos(positions, sha1);
 373
 374         if (pos < kh_end(positions)) {
 375                 int bitmap_pos = kh_value(positions, pos);
 376                 return bitmap_pos + bitmap_git.pack->num_objects;
 377         }
 378
 379         return -1;
 380 }
 381
 382 static inline int bitmap_position_packfile(const unsigned char *sha1)
 383 {
 384         off_t offset = find_pack_entry_one(sha1, bitmap_git.pack);
 385         if (!offset)
 386                 return -1;
 387
 388         return find_revindex_position(bitmap_git.reverse_index, offset);
 389 }
 390
 391 static int bitmap_position(const unsigned char *sha1)
 392 {
 393         int pos = bitmap_position_packfile(sha1);
 394         return (pos >= 0) ? pos : bitmap_position_extended(sha1);
 395 }
 396
 397 static int ext_index_add_object(struct object *object, const char *name)
 398 {
 399         struct eindex *eindex = &bitmap_git.ext_index;
 400
 401         khiter_t hash_pos;
 402         int hash_ret;
 403         int bitmap_pos;
 404
 405         hash_pos = kh_put_sha1_pos(eindex->positions, object->sha1, &hash_ret);
 406         if (hash_ret > 0) {
 407                 if (eindex->count >= eindex->alloc) {
 408                         eindex->alloc = (eindex->alloc + 16) * 3 / 2;
 409                         REALLOC_ARRAY(eindex->objects, eindex->alloc);
 410                         REALLOC_ARRAY(eindex->hashes, eindex->alloc);
 411                 }
 412
 413                 bitmap_pos = eindex->count;
 414                 eindex->objects[eindex->count] = object;
 415                 eindex->hashes[eindex->count] = pack_name_hash(name);
 416                 kh_value(eindex->positions, hash_pos) = bitmap_pos;
 417                 eindex->count++;
 418         } else {
 419                 bitmap_pos = kh_value(eindex->positions, hash_pos);
 420         }
 421
 422         return bitmap_pos + bitmap_git.pack->num_objects;
 423 }
 424
 425 static void show_object(struct object *object, const struct name_path *path,
 426                         const char *last, void *data)
 427 {
 428         struct bitmap *base = data;
 429         int bitmap_pos;
 430
 431         bitmap_pos = bitmap_position(object->sha1);
 432
 433         if (bitmap_pos < 0) {
 434                 char *name = path_name(path, last);
 435                 bitmap_pos = ext_index_add_object(object, name);
 436                 free(name);
 437         }
 438
 439         bitmap_set(base, bitmap_pos);
 440 }
 441
 442 static void show_commit(struct commit *commit, void *data)
 443 {
 444 }
 445
 446 static int add_to_include_set(struct include_data *data,
 447                               const unsigned char *sha1,
 448                               int bitmap_pos)
 449 {
 450         khiter_t hash_pos;
 451
 452         if (data->seen && bitmap_get(data->seen, bitmap_pos))
 453                 return 0;
 454
 455         if (bitmap_get(data->base, bitmap_pos))
 456                 return 0;
 457
 458         hash_pos = kh_get_sha1(bitmap_git.bitmaps, sha1);
 459         if (hash_pos < kh_end(bitmap_git.bitmaps)) {
 460                 struct stored_bitmap *st = kh_value(bitmap_git.bitmaps, hash_pos);
 461                 bitmap_or_ewah(data->base, lookup_stored_bitmap(st));
 462                 return 0;
 463         }
 464
 465         bitmap_set(data->base, bitmap_pos);
 466         return 1;
 467 }
 468
 469 static int should_include(struct commit *commit, void *_data)
 470 {
 471         struct include_data *data = _data;
 472         int bitmap_pos;
 473
 474         bitmap_pos = bitmap_position(commit->object.sha1);
 475         if (bitmap_pos < 0)
 476                 bitmap_pos = ext_index_add_object((struct object *)commit, NULL);
 477
 478         if (!add_to_include_set(data, commit->object.sha1, bitmap_pos)) {
 479                 struct commit_list *parent = commit->parents;
 480
 481                 while (parent) {
 482                         parent->item->object.flags |= SEEN;
 483                         parent = parent->next;
 484                 }
 485
 486                 return 0;
 487         }
 488
 489         return 1;
 490 }
 491
 492 static struct bitmap *find_objects(struct rev_info *revs,
 493                                    struct object_list *roots,
 494                                    struct bitmap *seen)
 495 {
 496         struct bitmap *base = NULL;
 497         int needs_walk = 0;
 498
 499         struct object_list *not_mapped = NULL;
 500
 501         /*
 502          * Go through all the roots for the walk. The ones that have bitmaps
 503          * on the bitmap index will be `or`ed together to form an initial
 504          * global reachability analysis.
 505          *
 506          * The ones without bitmaps in the index will be stored in the
 507          * `not_mapped_list` for further processing.
 508          */
 509         while (roots) {
 510                 struct object *object = roots->item;
 511                 roots = roots->next;
 512
 513                 if (object->type == OBJ_COMMIT) {
 514                         khiter_t pos = kh_get_sha1(bitmap_git.bitmaps, object->sha1);
 515
 516                         if (pos < kh_end(bitmap_git.bitmaps)) {
 517                                 struct stored_bitmap *st = kh_value(bitmap_git.bitmaps, pos);
 518                                 struct ewah_bitmap *or_with = lookup_stored_bitmap(st);
 519
 520                                 if (base == NULL)
 521                                         base = ewah_to_bitmap(or_with);
 522                                 else
 523                                         bitmap_or_ewah(base, or_with);
 524
 525                                 object->flags |= SEEN;
 526                                 continue;
 527                         }
 528                 }
 529
 530                 object_list_insert(object, &not_mapped);
 531         }
 532
 533         /*
 534          * Best case scenario: We found bitmaps for all the roots,
 535          * so the resulting `or` bitmap has the full reachability analysis
 536          */
 537         if (not_mapped == NULL)
 538                 return base;
 539
 540         roots = not_mapped;
 541
 542         /*
 543          * Let's iterate through all the roots that don't have bitmaps to
 544          * check if we can determine them to be reachable from the existing
 545          * global bitmap.
 546          *
 547          * If we cannot find them in the existing global bitmap, we'll need
 548          * to push them to an actual walk and run it until we can confirm
 549          * they are reachable
 550          */
 551         while (roots) {
 552                 struct object *object = roots->item;
 553                 int pos;
 554
 555                 roots = roots->next;
 556                 pos = bitmap_position(object->sha1);
 557
 558                 if (pos < 0 || base == NULL || !bitmap_get(base, pos)) {
 559                         object->flags &= ~UNINTERESTING;
 560                         add_pending_object(revs, object, "");
 561                         needs_walk = 1;
 562                 } else {
 563                         object->flags |= SEEN;
 564                 }
 565         }
 566
 567         if (needs_walk) {
 568                 struct include_data incdata;
 569
 570                 if (base == NULL)
 571                         base = bitmap_new();
 572
 573                 incdata.base = base;
 574                 incdata.seen = seen;
 575
 576                 revs->include_check = should_include;
 577                 revs->include_check_data = &incdata;
 578
 579                 if (prepare_revision_walk(revs))
 580                         die("revision walk setup failed");
 581
 582                 traverse_commit_list(revs, show_commit, show_object, base);
 583         }
 584
 585         return base;
 586 }
 587
 588 static void show_extended_objects(struct bitmap *objects,
 589                                   show_reachable_fn show_reach)
 590 {
 591         struct eindex *eindex = &bitmap_git.ext_index;
 592         uint32_t i;
 593
 594         for (i = 0; i < eindex->count; ++i) {
 595                 struct object *obj;
 596
 597                 if (!bitmap_get(objects, bitmap_git.pack->num_objects + i))
 598                         continue;
 599
 600                 obj = eindex->objects[i];
 601                 show_reach(obj->sha1, obj->type, 0, eindex->hashes[i], NULL, 0);
 602         }
 603 }
 604
 605 static void show_objects_for_type(
 606         struct bitmap *objects,
 607         struct ewah_bitmap *type_filter,
 608         enum object_type object_type,
 609         show_reachable_fn show_reach)
 610 {
 611         size_t pos = 0, i = 0;
 612         uint32_t offset;
 613
 614         struct ewah_iterator it;
 615         eword_t filter;
 616
 617         if (bitmap_git.reuse_objects == bitmap_git.pack->num_objects)
 618                 return;
 619
 620         ewah_iterator_init(&it, type_filter);
 621
 622         while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
 623                 eword_t word = objects->words[i] & filter;
 624
 625                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
 626                         const unsigned char *sha1;
 627                         struct revindex_entry *entry;
 628                         uint32_t hash = 0;
 629
 630                         if ((word >> offset) == 0)
 631                                 break;
 632
 633                         offset += ewah_bit_ctz64(word >> offset);
 634
 635                         if (pos + offset < bitmap_git.reuse_objects)
 636                                 continue;
 637
 638                         entry = &bitmap_git.reverse_index->revindex[pos + offset];
 639                         sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
 640
 641                         if (bitmap_git.hashes)
 642                                 hash = ntohl(bitmap_git.hashes[entry->nr]);
 643
 644                         show_reach(sha1, object_type, 0, hash, bitmap_git.pack, entry->offset);
 645                 }
 646
 647                 pos += BITS_IN_EWORD;
 648                 i++;
 649         }
 650 }
 651
 652 static int in_bitmapped_pack(struct object_list *roots)
 653 {
 654         while (roots) {
 655                 struct object *object = roots->item;
 656                 roots = roots->next;
 657
 658                 if (find_pack_entry_one(object->sha1, bitmap_git.pack) > 0)
 659                         return 1;
 660         }
 661
 662         return 0;
 663 }
 664
 665 int prepare_bitmap_walk(struct rev_info *revs)
 666 {
 667         unsigned int i;
 668         unsigned int pending_nr = revs->pending.nr;
 669         struct object_array_entry *pending_e = revs->pending.objects;
 670
 671         struct object_list *wants = NULL;
 672         struct object_list *haves = NULL;
 673
 674         struct bitmap *wants_bitmap = NULL;
 675         struct bitmap *haves_bitmap = NULL;
 676
 677         if (!bitmap_git.loaded) {
 678                 /* try to open a bitmapped pack, but don't parse it yet
 679                  * because we may not need to use it */
 680                 if (open_pack_bitmap() < 0)
 681                         return -1;
 682         }
 683
 684         for (i = 0; i < pending_nr; ++i) {
 685                 struct object *object = pending_e[i].item;
 686
 687                 if (object->type == OBJ_NONE)
 688                         parse_object_or_die(object->sha1, NULL);
 689
 690                 while (object->type == OBJ_TAG) {
 691                         struct tag *tag = (struct tag *) object;
 692
 693                         if (object->flags & UNINTERESTING)
 694                                 object_list_insert(object, &haves);
 695                         else
 696                                 object_list_insert(object, &wants);
 697
 698                         if (!tag->tagged)
 699                                 die("bad tag");
 700                         object = parse_object_or_die(tag->tagged->sha1, NULL);
 701                 }
 702
 703                 if (object->flags & UNINTERESTING)
 704                         object_list_insert(object, &haves);
 705                 else
 706                         object_list_insert(object, &wants);
 707         }
 708
 709         /*
 710          * if we have a HAVES list, but none of those haves is contained
 711          * in the packfile that has a bitmap, we don't have anything to
 712          * optimize here
 713          */
 714         if (haves && !in_bitmapped_pack(haves))
 715                 return -1;
 716
 717         /* if we don't want anything, we're done here */
 718         if (!wants)
 719                 return -1;
 720
 721         /*
 722          * now we're going to use bitmaps, so load the actual bitmap entries
 723          * from disk. this is the point of no return; after this the rev_list
 724          * becomes invalidated and we must perform the revwalk through bitmaps
 725          */
 726         if (!bitmap_git.loaded && load_pack_bitmap() < 0)
 727                 return -1;
 728
 729         revs->pending.nr = 0;
 730         revs->pending.alloc = 0;
 731         revs->pending.objects = NULL;
 732
 733         if (haves) {
 734                 revs->ignore_missing_links = 1;
 735                 haves_bitmap = find_objects(revs, haves, NULL);
 736                 reset_revision_walk();
 737                 revs->ignore_missing_links = 0;
 738
 739                 if (haves_bitmap == NULL)
 740                         die("BUG: failed to perform bitmap walk");
 741         }
 742
 743         wants_bitmap = find_objects(revs, wants, haves_bitmap);
 744
 745         if (!wants_bitmap)
 746                 die("BUG: failed to perform bitmap walk");
 747
 748         if (haves_bitmap)
 749                 bitmap_and_not(wants_bitmap, haves_bitmap);
 750
 751         bitmap_git.result = wants_bitmap;
 752
 753         bitmap_free(haves_bitmap);
 754         return 0;
 755 }
 756
 757 int reuse_partial_packfile_from_bitmap(struct packed_git **packfile,
 758                                        uint32_t *entries,
 759                                        off_t *up_to)
 760 {
 761         /*
 762          * Reuse the packfile content if we need more than
 763          * 90% of its objects
 764          */
 765         static const double REUSE_PERCENT = 0.9;
 766
 767         struct bitmap *result = bitmap_git.result;
 768         uint32_t reuse_threshold;
 769         uint32_t i, reuse_objects = 0;
 770
 771         assert(result);
 772
 773         for (i = 0; i < result->word_alloc; ++i) {
 774                 if (result->words[i] != (eword_t)~0) {
 775                         reuse_objects += ewah_bit_ctz64(~result->words[i]);
 776                         break;
 777                 }
 778
 779                 reuse_objects += BITS_IN_EWORD;
 780         }
 781
 782 #ifdef GIT_BITMAP_DEBUG
 783         {
 784                 const unsigned char *sha1;
 785                 struct revindex_entry *entry;
 786
 787                 entry = &bitmap_git.reverse_index->revindex[reuse_objects];
 788                 sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
 789
 790                 fprintf(stderr, "Failed to reuse at %d (%016llx)\n",
 791                         reuse_objects, result->words[i]);
 792                 fprintf(stderr, " %s\n", sha1_to_hex(sha1));
 793         }
 794 #endif
 795
 796         if (!reuse_objects)
 797                 return -1;
 798
 799         if (reuse_objects >= bitmap_git.pack->num_objects) {
 800                 bitmap_git.reuse_objects = *entries = bitmap_git.pack->num_objects;
 801                 *up_to = -1; /* reuse the full pack */
 802                 *packfile = bitmap_git.pack;
 803                 return 0;
 804         }
 805
 806         reuse_threshold = bitmap_popcount(bitmap_git.result) * REUSE_PERCENT;
 807
 808         if (reuse_objects < reuse_threshold)
 809                 return -1;
 810
 811         bitmap_git.reuse_objects = *entries = reuse_objects;
 812         *up_to = bitmap_git.reverse_index->revindex[reuse_objects].offset;
 813         *packfile = bitmap_git.pack;
 814
 815         return 0;
 816 }
 817
 818 void traverse_bitmap_commit_list(show_reachable_fn show_reachable)
 819 {
 820         assert(bitmap_git.result);
 821
 822         show_objects_for_type(bitmap_git.result, bitmap_git.commits,
 823                 OBJ_COMMIT, show_reachable);
 824         show_objects_for_type(bitmap_git.result, bitmap_git.trees,
 825                 OBJ_TREE, show_reachable);
 826         show_objects_for_type(bitmap_git.result, bitmap_git.blobs,
 827                 OBJ_BLOB, show_reachable);
 828         show_objects_for_type(bitmap_git.result, bitmap_git.tags,
 829                 OBJ_TAG, show_reachable);
 830
 831         show_extended_objects(bitmap_git.result, show_reachable);
 832
 833         bitmap_free(bitmap_git.result);
 834         bitmap_git.result = NULL;
 835 }
 836
 837 static uint32_t count_object_type(struct bitmap *objects,
 838                                   enum object_type type)
 839 {
 840         struct eindex *eindex = &bitmap_git.ext_index;
 841
 842         uint32_t i = 0, count = 0;
 843         struct ewah_iterator it;
 844         eword_t filter;
 845
 846         switch (type) {
 847         case OBJ_COMMIT:
 848                 ewah_iterator_init(&it, bitmap_git.commits);
 849                 break;
 850
 851         case OBJ_TREE:
 852                 ewah_iterator_init(&it, bitmap_git.trees);
 853                 break;
 854
 855         case OBJ_BLOB:
 856                 ewah_iterator_init(&it, bitmap_git.blobs);
 857                 break;
 858
 859         case OBJ_TAG:
 860                 ewah_iterator_init(&it, bitmap_git.tags);
 861                 break;
 862
 863         default:
 864                 return 0;
 865         }
 866
 867         while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
 868                 eword_t word = objects->words[i++] & filter;
 869                 count += ewah_bit_popcount64(word);
 870         }
 871
 872         for (i = 0; i < eindex->count; ++i) {
 873                 if (eindex->objects[i]->type == type &&
 874                         bitmap_get(objects, bitmap_git.pack->num_objects + i))
 875                         count++;
 876         }
 877
 878         return count;
 879 }
 880
 881 void count_bitmap_commit_list(uint32_t *commits, uint32_t *trees,
 882                               uint32_t *blobs, uint32_t *tags)
 883 {
 884         assert(bitmap_git.result);
 885
 886         if (commits)
 887                 *commits = count_object_type(bitmap_git.result, OBJ_COMMIT);
 888
 889         if (trees)
 890                 *trees = count_object_type(bitmap_git.result, OBJ_TREE);
 891
 892         if (blobs)
 893                 *blobs = count_object_type(bitmap_git.result, OBJ_BLOB);
 894
 895         if (tags)
 896                 *tags = count_object_type(bitmap_git.result, OBJ_TAG);
 897 }
 898
 899 struct bitmap_test_data {
 900         struct bitmap *base;
 901         struct progress *prg;
 902         size_t seen;
 903 };
 904
 905 static void test_show_object(struct object *object,
 906                              const struct name_path *path,
 907                              const char *last, void *data)
 908 {
 909         struct bitmap_test_data *tdata = data;
 910         int bitmap_pos;
 911
 912         bitmap_pos = bitmap_position(object->sha1);
 913         if (bitmap_pos < 0)
 914                 die("Object not in bitmap: %s\n", sha1_to_hex(object->sha1));
 915
 916         bitmap_set(tdata->base, bitmap_pos);
 917         display_progress(tdata->prg, ++tdata->seen);
 918 }
 919
 920 static void test_show_commit(struct commit *commit, void *data)
 921 {
 922         struct bitmap_test_data *tdata = data;
 923         int bitmap_pos;
 924
 925         bitmap_pos = bitmap_position(commit->object.sha1);
 926         if (bitmap_pos < 0)
 927                 die("Object not in bitmap: %s\n", sha1_to_hex(commit->object.sha1));
 928
 929         bitmap_set(tdata->base, bitmap_pos);
 930         display_progress(tdata->prg, ++tdata->seen);
 931 }
 932
 933 void test_bitmap_walk(struct rev_info *revs)
 934 {
 935         struct object *root;
 936         struct bitmap *result = NULL;
 937         khiter_t pos;
 938         size_t result_popcnt;
 939         struct bitmap_test_data tdata;
 940
 941         if (prepare_bitmap_git())
 942                 die("failed to load bitmap indexes");
 943
 944         if (revs->pending.nr != 1)
 945                 die("you must specify exactly one commit to test");
 946
 947         fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
 948                 bitmap_git.version, bitmap_git.entry_count);
 949
 950         root = revs->pending.objects[0].item;
 951         pos = kh_get_sha1(bitmap_git.bitmaps, root->sha1);
 952
 953         if (pos < kh_end(bitmap_git.bitmaps)) {
 954                 struct stored_bitmap *st = kh_value(bitmap_git.bitmaps, pos);
 955                 struct ewah_bitmap *bm = lookup_stored_bitmap(st);
 956
 957                 fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
 958                         sha1_to_hex(root->sha1), (int)bm->bit_size, ewah_checksum(bm));
 959
 960                 result = ewah_to_bitmap(bm);
 961         }
 962
 963         if (result == NULL)
 964                 die("Commit %s doesn't have an indexed bitmap", sha1_to_hex(root->sha1));
 965
 966         revs->tag_objects = 1;
 967         revs->tree_objects = 1;
 968         revs->blob_objects = 1;
 969
 970         result_popcnt = bitmap_popcount(result);
 971
 972         if (prepare_revision_walk(revs))
 973                 die("revision walk setup failed");
 974
 975         tdata.base = bitmap_new();
 976         tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
 977         tdata.seen = 0;
 978
 979         traverse_commit_list(revs, &test_show_commit, &test_show_object, &tdata);
 980
 981         stop_progress(&tdata.prg);
 982
 983         if (bitmap_equals(result, tdata.base))
 984                 fprintf(stderr, "OK!\n");
 985         else
 986                 fprintf(stderr, "Mismatch!\n");
 987
 988         bitmap_free(result);
 989 }
 990
 991 static int rebuild_bitmap(uint32_t *reposition,
 992                           struct ewah_bitmap *source,
 993                           struct bitmap *dest)
 994 {
 995         uint32_t pos = 0;
 996         struct ewah_iterator it;
 997         eword_t word;
 998
 999         ewah_iterator_init(&it, source);
1000
1001         while (ewah_iterator_next(&word, &it)) {
1002                 uint32_t offset, bit_pos;
1003
1004                 for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
1005                         if ((word >> offset) == 0)
1006                                 break;
1007
1008                         offset += ewah_bit_ctz64(word >> offset);
1009
1010                         bit_pos = reposition[pos + offset];
1011                         if (bit_pos > 0)
1012                                 bitmap_set(dest, bit_pos - 1);
1013                         else /* can't reuse, we don't have the object */
1014                                 return -1;
1015                 }
1016
1017                 pos += BITS_IN_EWORD;
1018         }
1019         return 0;
1020 }
1021
1022 int rebuild_existing_bitmaps(struct packing_data *mapping,
1023                              khash_sha1 *reused_bitmaps,
1024                              int show_progress)
1025 {
1026         uint32_t i, num_objects;
1027         uint32_t *reposition;
1028         struct bitmap *rebuild;
1029         struct stored_bitmap *stored;
1030         struct progress *progress = NULL;
1031
1032         khiter_t hash_pos;
1033         int hash_ret;
1034
1035         if (prepare_bitmap_git() < 0)
1036                 return -1;
1037
1038         num_objects = bitmap_git.pack->num_objects;
1039         reposition = xcalloc(num_objects, sizeof(uint32_t));
1040
1041         for (i = 0; i < num_objects; ++i) {
1042                 const unsigned char *sha1;
1043                 struct revindex_entry *entry;
1044                 struct object_entry *oe;
1045
1046                 entry = &bitmap_git.reverse_index->revindex[i];
1047                 sha1 = nth_packed_object_sha1(bitmap_git.pack, entry->nr);
1048                 oe = packlist_find(mapping, sha1, NULL);
1049
1050                 if (oe)
1051                         reposition[i] = oe->in_pack_pos + 1;
1052         }
1053
1054         rebuild = bitmap_new();
1055         i = 0;
1056
1057         if (show_progress)
1058                 progress = start_progress("Reusing bitmaps", 0);
1059
1060         kh_foreach_value(bitmap_git.bitmaps, stored, {
1061                 if (stored->flags & BITMAP_FLAG_REUSE) {
1062                         if (!rebuild_bitmap(reposition,
1063                                             lookup_stored_bitmap(stored),
1064                                             rebuild)) {
1065                                 hash_pos = kh_put_sha1(reused_bitmaps,
1066                                                        stored->sha1,
1067                                                        &hash_ret);
1068                                 kh_value(reused_bitmaps, hash_pos) =
1069                                         bitmap_to_ewah(rebuild);
1070                         }
1071                         bitmap_reset(rebuild);
1072                         display_progress(progress, ++i);
1073                 }
1074         });
1075
1076         stop_progress(&progress);
1077
1078         free(reposition);
1079         bitmap_free(rebuild);
1080         return 0;
1081 }