pack-bitmap.con commit Merge branch 'ds/include-exclude' (9755f70)
   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
  16/*
  17 * An entry on the bitmap index, representing the bitmap for a given
  18 * commit.
  19 */
  20struct stored_bitmap {
  21        struct object_id oid;
  22        struct ewah_bitmap *root;
  23        struct stored_bitmap *xor;
  24        int flags;
  25};
  26
  27/*
  28 * The active bitmap index for a repository. By design, repositories only have
  29 * a single bitmap index available (the index for the biggest packfile in
  30 * the repository), since bitmap indexes need full closure.
  31 *
  32 * If there is more than one bitmap index available (e.g. because of alternates),
  33 * the active bitmap index is the largest one.
  34 */
  35struct bitmap_index {
  36        /* Packfile to which this bitmap index belongs to */
  37        struct packed_git *pack;
  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 object ID -> `stored_bitmap` for all the bitmapped commits */
  64        kh_oid_map_t *bitmaps;
  65
  66        /* Number of bitmapped commits */
  67        uint32_t entry_count;
  68
  69        /* If not NULL, this is a name-hash cache pointing into map. */
  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                kh_oid_pos_t *positions;
  84        } ext_index;
  85
  86        /* Bitmap result of the last performed walk */
  87        struct bitmap *result;
  88
  89        /* "have" bitmap from the last performed walk */
  90        struct bitmap *haves;
  91
  92        /* Version of the bitmap index */
  93        unsigned int version;
  94};
  95
  96static 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 */
 119static struct ewah_bitmap *read_bitmap_1(struct bitmap_index *index)
 120{
 121        struct ewah_bitmap *b = ewah_pool_new();
 122
 123        ssize_t 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
 137static 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) + the_hash_algo->rawsz)
 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 - the_hash_algo->rawsz;
 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) - GIT_MAX_RAWSZ + the_hash_algo->rawsz;
 167        return 0;
 168}
 169
 170static struct stored_bitmap *store_bitmap(struct bitmap_index *index,
 171                                          struct ewah_bitmap *root,
 172                                          const unsigned char *hash,
 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        oidread(&stored->oid, hash);
 185
 186        hash_pos = kh_put_oid_map(index->bitmaps, stored->oid, &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", hash_to_hex(hash));
 193                return NULL;
 194        }
 195
 196        kh_value(index->bitmaps, hash_pos) = stored;
 197        return stored;
 198}
 199
 200static 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
 207static 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
 214static 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
 253static char *pack_bitmap_filename(struct packed_git *p)
 254{
 255        size_t len;
 256
 257        if (!strip_suffix(p->pack_name, ".pack", &len))
 258                BUG("pack_name does not end in .pack");
 259        return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
 260}
 261
 262static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git *packfile)
 263{
 264        int fd;
 265        struct stat st;
 266        char *idx_name;
 267
 268        if (open_pack_index(packfile))
 269                return -1;
 270
 271        idx_name = pack_bitmap_filename(packfile);
 272        fd = git_open(idx_name);
 273        free(idx_name);
 274
 275        if (fd < 0)
 276                return -1;
 277
 278        if (fstat(fd, &st)) {
 279                close(fd);
 280                return -1;
 281        }
 282
 283        if (bitmap_git->pack) {
 284                warning("ignoring extra bitmap file: %s", packfile->pack_name);
 285                close(fd);
 286                return -1;
 287        }
 288
 289        bitmap_git->pack = packfile;
 290        bitmap_git->map_size = xsize_t(st.st_size);
 291        bitmap_git->map = xmmap(NULL, bitmap_git->map_size, PROT_READ, MAP_PRIVATE, fd, 0);
 292        bitmap_git->map_pos = 0;
 293        close(fd);
 294
 295        if (load_bitmap_header(bitmap_git) < 0) {
 296                munmap(bitmap_git->map, bitmap_git->map_size);
 297                bitmap_git->map = NULL;
 298                bitmap_git->map_size = 0;
 299                return -1;
 300        }
 301
 302        return 0;
 303}
 304
 305static int load_pack_bitmap(struct bitmap_index *bitmap_git)
 306{
 307        assert(bitmap_git->map);
 308
 309        bitmap_git->bitmaps = kh_init_oid_map();
 310        bitmap_git->ext_index.positions = kh_init_oid_pos();
 311        if (load_pack_revindex(bitmap_git->pack))
 312                goto failed;
 313
 314        if (!(bitmap_git->commits = read_bitmap_1(bitmap_git)) ||
 315                !(bitmap_git->trees = read_bitmap_1(bitmap_git)) ||
 316                !(bitmap_git->blobs = read_bitmap_1(bitmap_git)) ||
 317                !(bitmap_git->tags = read_bitmap_1(bitmap_git)))
 318                goto failed;
 319
 320        if (load_bitmap_entries_v1(bitmap_git) < 0)
 321                goto failed;
 322
 323        return 0;
 324
 325failed:
 326        munmap(bitmap_git->map, bitmap_git->map_size);
 327        bitmap_git->map = NULL;
 328        bitmap_git->map_size = 0;
 329        return -1;
 330}
 331
 332static int open_pack_bitmap(struct repository *r,
 333                            struct bitmap_index *bitmap_git)
 334{
 335        struct packed_git *p;
 336        int ret = -1;
 337
 338        assert(!bitmap_git->map);
 339
 340        for (p = get_all_packs(r); p; p = p->next) {
 341                if (open_pack_bitmap_1(bitmap_git, p) == 0)
 342                        ret = 0;
 343        }
 344
 345        return ret;
 346}
 347
 348struct bitmap_index *prepare_bitmap_git(struct repository *r)
 349{
 350        struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
 351
 352        if (!open_pack_bitmap(r, bitmap_git) && !load_pack_bitmap(bitmap_git))
 353                return bitmap_git;
 354
 355        free_bitmap_index(bitmap_git);
 356        return NULL;
 357}
 358
 359struct include_data {
 360        struct bitmap_index *bitmap_git;
 361        struct bitmap *base;
 362        struct bitmap *seen;
 363};
 364
 365static inline int bitmap_position_extended(struct bitmap_index *bitmap_git,
 366                                           const struct object_id *oid)
 367{
 368        kh_oid_pos_t *positions = bitmap_git->ext_index.positions;
 369        khiter_t pos = kh_get_oid_pos(positions, *oid);
 370
 371        if (pos < kh_end(positions)) {
 372                int bitmap_pos = kh_value(positions, pos);
 373                return bitmap_pos + bitmap_git->pack->num_objects;
 374        }
 375
 376        return -1;
 377}
 378
 379static inline int bitmap_position_packfile(struct bitmap_index *bitmap_git,
 380                                           const struct object_id *oid)
 381{
 382        off_t offset = find_pack_entry_one(oid->hash, bitmap_git->pack);
 383        if (!offset)
 384                return -1;
 385
 386        return find_revindex_position(bitmap_git->pack, offset);
 387}
 388
 389static int bitmap_position(struct bitmap_index *bitmap_git,
 390                           const struct object_id *oid)
 391{
 392        int pos = bitmap_position_packfile(bitmap_git, oid);
 393        return (pos >= 0) ? pos : bitmap_position_extended(bitmap_git, oid);
 394}
 395
 396static int ext_index_add_object(struct bitmap_index *bitmap_git,
 397                                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_oid_pos(eindex->positions, object->oid, &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
 425struct bitmap_show_data {
 426        struct bitmap_index *bitmap_git;
 427        struct bitmap *base;
 428};
 429
 430static void show_object(struct object *object, const char *name, void *data_)
 431{
 432        struct bitmap_show_data *data = data_;
 433        int bitmap_pos;
 434
 435        bitmap_pos = bitmap_position(data->bitmap_git, &object->oid);
 436
 437        if (bitmap_pos < 0)
 438                bitmap_pos = ext_index_add_object(data->bitmap_git, object,
 439                                                  name);
 440
 441        bitmap_set(data->base, bitmap_pos);
 442}
 443
 444static void show_commit(struct commit *commit, void *data)
 445{
 446}
 447
 448static int add_to_include_set(struct bitmap_index *bitmap_git,
 449                              struct include_data *data,
 450                              const struct object_id *oid,
 451                              int bitmap_pos)
 452{
 453        khiter_t hash_pos;
 454
 455        if (data->seen && bitmap_get(data->seen, bitmap_pos))
 456                return 0;
 457
 458        if (bitmap_get(data->base, bitmap_pos))
 459                return 0;
 460
 461        hash_pos = kh_get_oid_map(bitmap_git->bitmaps, *oid);
 462        if (hash_pos < kh_end(bitmap_git->bitmaps)) {
 463                struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, hash_pos);
 464                bitmap_or_ewah(data->base, lookup_stored_bitmap(st));
 465                return 0;
 466        }
 467
 468        bitmap_set(data->base, bitmap_pos);
 469        return 1;
 470}
 471
 472static int should_include(struct commit *commit, void *_data)
 473{
 474        struct include_data *data = _data;
 475        int bitmap_pos;
 476
 477        bitmap_pos = bitmap_position(data->bitmap_git, &commit->object.oid);
 478        if (bitmap_pos < 0)
 479                bitmap_pos = ext_index_add_object(data->bitmap_git,
 480                                                  (struct object *)commit,
 481                                                  NULL);
 482
 483        if (!add_to_include_set(data->bitmap_git, data, &commit->object.oid,
 484                                bitmap_pos)) {
 485                struct commit_list *parent = commit->parents;
 486
 487                while (parent) {
 488                        parent->item->object.flags |= SEEN;
 489                        parent = parent->next;
 490                }
 491
 492                return 0;
 493        }
 494
 495        return 1;
 496}
 497
 498static struct bitmap *find_objects(struct bitmap_index *bitmap_git,
 499                                   struct rev_info *revs,
 500                                   struct object_list *roots,
 501                                   struct bitmap *seen)
 502{
 503        struct bitmap *base = NULL;
 504        int needs_walk = 0;
 505
 506        struct object_list *not_mapped = NULL;
 507
 508        /*
 509         * Go through all the roots for the walk. The ones that have bitmaps
 510         * on the bitmap index will be `or`ed together to form an initial
 511         * global reachability analysis.
 512         *
 513         * The ones without bitmaps in the index will be stored in the
 514         * `not_mapped_list` for further processing.
 515         */
 516        while (roots) {
 517                struct object *object = roots->item;
 518                roots = roots->next;
 519
 520                if (object->type == OBJ_COMMIT) {
 521                        khiter_t pos = kh_get_oid_map(bitmap_git->bitmaps, object->oid);
 522
 523                        if (pos < kh_end(bitmap_git->bitmaps)) {
 524                                struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, pos);
 525                                struct ewah_bitmap *or_with = lookup_stored_bitmap(st);
 526
 527                                if (base == NULL)
 528                                        base = ewah_to_bitmap(or_with);
 529                                else
 530                                        bitmap_or_ewah(base, or_with);
 531
 532                                object->flags |= SEEN;
 533                                continue;
 534                        }
 535                }
 536
 537                object_list_insert(object, &not_mapped);
 538        }
 539
 540        /*
 541         * Best case scenario: We found bitmaps for all the roots,
 542         * so the resulting `or` bitmap has the full reachability analysis
 543         */
 544        if (not_mapped == NULL)
 545                return base;
 546
 547        roots = not_mapped;
 548
 549        /*
 550         * Let's iterate through all the roots that don't have bitmaps to
 551         * check if we can determine them to be reachable from the existing
 552         * global bitmap.
 553         *
 554         * If we cannot find them in the existing global bitmap, we'll need
 555         * to push them to an actual walk and run it until we can confirm
 556         * they are reachable
 557         */
 558        while (roots) {
 559                struct object *object = roots->item;
 560                int pos;
 561
 562                roots = roots->next;
 563                pos = bitmap_position(bitmap_git, &object->oid);
 564
 565                if (pos < 0 || base == NULL || !bitmap_get(base, pos)) {
 566                        object->flags &= ~UNINTERESTING;
 567                        add_pending_object(revs, object, "");
 568                        needs_walk = 1;
 569                } else {
 570                        object->flags |= SEEN;
 571                }
 572        }
 573
 574        if (needs_walk) {
 575                struct include_data incdata;
 576                struct bitmap_show_data show_data;
 577
 578                if (base == NULL)
 579                        base = bitmap_new();
 580
 581                incdata.bitmap_git = bitmap_git;
 582                incdata.base = base;
 583                incdata.seen = seen;
 584
 585                revs->include_check = should_include;
 586                revs->include_check_data = &incdata;
 587
 588                if (prepare_revision_walk(revs))
 589                        die("revision walk setup failed");
 590
 591                show_data.bitmap_git = bitmap_git;
 592                show_data.base = base;
 593
 594                traverse_commit_list(revs, show_commit, show_object,
 595                                     &show_data);
 596        }
 597
 598        return base;
 599}
 600
 601static void show_extended_objects(struct bitmap_index *bitmap_git,
 602                                  show_reachable_fn show_reach)
 603{
 604        struct bitmap *objects = bitmap_git->result;
 605        struct eindex *eindex = &bitmap_git->ext_index;
 606        uint32_t i;
 607
 608        for (i = 0; i < eindex->count; ++i) {
 609                struct object *obj;
 610
 611                if (!bitmap_get(objects, bitmap_git->pack->num_objects + i))
 612                        continue;
 613
 614                obj = eindex->objects[i];
 615                show_reach(&obj->oid, obj->type, 0, eindex->hashes[i], NULL, 0);
 616        }
 617}
 618
 619static void show_objects_for_type(
 620        struct bitmap_index *bitmap_git,
 621        struct ewah_bitmap *type_filter,
 622        enum object_type object_type,
 623        show_reachable_fn show_reach)
 624{
 625        size_t pos = 0, i = 0;
 626        uint32_t offset;
 627
 628        struct ewah_iterator it;
 629        eword_t filter;
 630
 631        struct bitmap *objects = bitmap_git->result;
 632
 633        if (bitmap_git->reuse_objects == bitmap_git->pack->num_objects)
 634                return;
 635
 636        ewah_iterator_init(&it, type_filter);
 637
 638        while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
 639                eword_t word = objects->words[i] & filter;
 640
 641                for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
 642                        struct object_id oid;
 643                        struct revindex_entry *entry;
 644                        uint32_t hash = 0;
 645
 646                        if ((word >> offset) == 0)
 647                                break;
 648
 649                        offset += ewah_bit_ctz64(word >> offset);
 650
 651                        if (pos + offset < bitmap_git->reuse_objects)
 652                                continue;
 653
 654                        entry = &bitmap_git->pack->revindex[pos + offset];
 655                        nth_packed_object_oid(&oid, bitmap_git->pack, entry->nr);
 656
 657                        if (bitmap_git->hashes)
 658                                hash = get_be32(bitmap_git->hashes + entry->nr);
 659
 660                        show_reach(&oid, object_type, 0, hash, bitmap_git->pack, entry->offset);
 661                }
 662
 663                pos += BITS_IN_EWORD;
 664                i++;
 665        }
 666}
 667
 668static int in_bitmapped_pack(struct bitmap_index *bitmap_git,
 669                             struct object_list *roots)
 670{
 671        while (roots) {
 672                struct object *object = roots->item;
 673                roots = roots->next;
 674
 675                if (find_pack_entry_one(object->oid.hash, bitmap_git->pack) > 0)
 676                        return 1;
 677        }
 678
 679        return 0;
 680}
 681
 682struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs)
 683{
 684        unsigned int i;
 685
 686        struct object_list *wants = NULL;
 687        struct object_list *haves = NULL;
 688
 689        struct bitmap *wants_bitmap = NULL;
 690        struct bitmap *haves_bitmap = NULL;
 691
 692        struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
 693        /* try to open a bitmapped pack, but don't parse it yet
 694         * because we may not need to use it */
 695        if (open_pack_bitmap(revs->repo, bitmap_git) < 0)
 696                goto cleanup;
 697
 698        for (i = 0; i < revs->pending.nr; ++i) {
 699                struct object *object = revs->pending.objects[i].item;
 700
 701                if (object->type == OBJ_NONE)
 702                        parse_object_or_die(&object->oid, NULL);
 703
 704                while (object->type == OBJ_TAG) {
 705                        struct tag *tag = (struct tag *) object;
 706
 707                        if (object->flags & UNINTERESTING)
 708                                object_list_insert(object, &haves);
 709                        else
 710                                object_list_insert(object, &wants);
 711
 712                        object = parse_object_or_die(get_tagged_oid(tag), NULL);
 713                }
 714
 715                if (object->flags & UNINTERESTING)
 716                        object_list_insert(object, &haves);
 717                else
 718                        object_list_insert(object, &wants);
 719        }
 720
 721        /*
 722         * if we have a HAVES list, but none of those haves is contained
 723         * in the packfile that has a bitmap, we don't have anything to
 724         * optimize here
 725         */
 726        if (haves && !in_bitmapped_pack(bitmap_git, haves))
 727                goto cleanup;
 728
 729        /* if we don't want anything, we're done here */
 730        if (!wants)
 731                goto cleanup;
 732
 733        /*
 734         * now we're going to use bitmaps, so load the actual bitmap entries
 735         * from disk. this is the point of no return; after this the rev_list
 736         * becomes invalidated and we must perform the revwalk through bitmaps
 737         */
 738        if (load_pack_bitmap(bitmap_git) < 0)
 739                goto cleanup;
 740
 741        object_array_clear(&revs->pending);
 742
 743        if (haves) {
 744                revs->ignore_missing_links = 1;
 745                haves_bitmap = find_objects(bitmap_git, revs, haves, NULL);
 746                reset_revision_walk();
 747                revs->ignore_missing_links = 0;
 748
 749                if (haves_bitmap == NULL)
 750                        BUG("failed to perform bitmap walk");
 751        }
 752
 753        wants_bitmap = find_objects(bitmap_git, revs, wants, haves_bitmap);
 754
 755        if (!wants_bitmap)
 756                BUG("failed to perform bitmap walk");
 757
 758        if (haves_bitmap)
 759                bitmap_and_not(wants_bitmap, haves_bitmap);
 760
 761        bitmap_git->result = wants_bitmap;
 762        bitmap_git->haves = haves_bitmap;
 763
 764        return bitmap_git;
 765
 766cleanup:
 767        free_bitmap_index(bitmap_git);
 768        return NULL;
 769}
 770
 771int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
 772                                       struct packed_git **packfile,
 773                                       uint32_t *entries,
 774                                       off_t *up_to)
 775{
 776        /*
 777         * Reuse the packfile content if we need more than
 778         * 90% of its objects
 779         */
 780        static const double REUSE_PERCENT = 0.9;
 781
 782        struct bitmap *result = bitmap_git->result;
 783        uint32_t reuse_threshold;
 784        uint32_t i, reuse_objects = 0;
 785
 786        assert(result);
 787
 788        for (i = 0; i < result->word_alloc; ++i) {
 789                if (result->words[i] != (eword_t)~0) {
 790                        reuse_objects += ewah_bit_ctz64(~result->words[i]);
 791                        break;
 792                }
 793
 794                reuse_objects += BITS_IN_EWORD;
 795        }
 796
 797#ifdef GIT_BITMAP_DEBUG
 798        {
 799                const unsigned char *sha1;
 800                struct revindex_entry *entry;
 801
 802                entry = &bitmap_git->reverse_index->revindex[reuse_objects];
 803                sha1 = nth_packed_object_sha1(bitmap_git->pack, entry->nr);
 804
 805                fprintf(stderr, "Failed to reuse at %d (%016llx)\n",
 806                        reuse_objects, result->words[i]);
 807                fprintf(stderr, " %s\n", hash_to_hex(sha1));
 808        }
 809#endif
 810
 811        if (!reuse_objects)
 812                return -1;
 813
 814        if (reuse_objects >= bitmap_git->pack->num_objects) {
 815                bitmap_git->reuse_objects = *entries = bitmap_git->pack->num_objects;
 816                *up_to = -1; /* reuse the full pack */
 817                *packfile = bitmap_git->pack;
 818                return 0;
 819        }
 820
 821        reuse_threshold = bitmap_popcount(bitmap_git->result) * REUSE_PERCENT;
 822
 823        if (reuse_objects < reuse_threshold)
 824                return -1;
 825
 826        bitmap_git->reuse_objects = *entries = reuse_objects;
 827        *up_to = bitmap_git->pack->revindex[reuse_objects].offset;
 828        *packfile = bitmap_git->pack;
 829
 830        return 0;
 831}
 832
 833void traverse_bitmap_commit_list(struct bitmap_index *bitmap_git,
 834                                 show_reachable_fn show_reachable)
 835{
 836        assert(bitmap_git->result);
 837
 838        show_objects_for_type(bitmap_git, bitmap_git->commits,
 839                OBJ_COMMIT, show_reachable);
 840        show_objects_for_type(bitmap_git, bitmap_git->trees,
 841                OBJ_TREE, show_reachable);
 842        show_objects_for_type(bitmap_git, bitmap_git->blobs,
 843                OBJ_BLOB, show_reachable);
 844        show_objects_for_type(bitmap_git, bitmap_git->tags,
 845                OBJ_TAG, show_reachable);
 846
 847        show_extended_objects(bitmap_git, show_reachable);
 848}
 849
 850static uint32_t count_object_type(struct bitmap_index *bitmap_git,
 851                                  enum object_type type)
 852{
 853        struct bitmap *objects = bitmap_git->result;
 854        struct eindex *eindex = &bitmap_git->ext_index;
 855
 856        uint32_t i = 0, count = 0;
 857        struct ewah_iterator it;
 858        eword_t filter;
 859
 860        switch (type) {
 861        case OBJ_COMMIT:
 862                ewah_iterator_init(&it, bitmap_git->commits);
 863                break;
 864
 865        case OBJ_TREE:
 866                ewah_iterator_init(&it, bitmap_git->trees);
 867                break;
 868
 869        case OBJ_BLOB:
 870                ewah_iterator_init(&it, bitmap_git->blobs);
 871                break;
 872
 873        case OBJ_TAG:
 874                ewah_iterator_init(&it, bitmap_git->tags);
 875                break;
 876
 877        default:
 878                return 0;
 879        }
 880
 881        while (i < objects->word_alloc && ewah_iterator_next(&filter, &it)) {
 882                eword_t word = objects->words[i++] & filter;
 883                count += ewah_bit_popcount64(word);
 884        }
 885
 886        for (i = 0; i < eindex->count; ++i) {
 887                if (eindex->objects[i]->type == type &&
 888                        bitmap_get(objects, bitmap_git->pack->num_objects + i))
 889                        count++;
 890        }
 891
 892        return count;
 893}
 894
 895void count_bitmap_commit_list(struct bitmap_index *bitmap_git,
 896                              uint32_t *commits, uint32_t *trees,
 897                              uint32_t *blobs, uint32_t *tags)
 898{
 899        assert(bitmap_git->result);
 900
 901        if (commits)
 902                *commits = count_object_type(bitmap_git, OBJ_COMMIT);
 903
 904        if (trees)
 905                *trees = count_object_type(bitmap_git, OBJ_TREE);
 906
 907        if (blobs)
 908                *blobs = count_object_type(bitmap_git, OBJ_BLOB);
 909
 910        if (tags)
 911                *tags = count_object_type(bitmap_git, OBJ_TAG);
 912}
 913
 914struct bitmap_test_data {
 915        struct bitmap_index *bitmap_git;
 916        struct bitmap *base;
 917        struct progress *prg;
 918        size_t seen;
 919};
 920
 921static void test_show_object(struct object *object, const char *name,
 922                             void *data)
 923{
 924        struct bitmap_test_data *tdata = data;
 925        int bitmap_pos;
 926
 927        bitmap_pos = bitmap_position(tdata->bitmap_git, &object->oid);
 928        if (bitmap_pos < 0)
 929                die("Object not in bitmap: %s\n", oid_to_hex(&object->oid));
 930
 931        bitmap_set(tdata->base, bitmap_pos);
 932        display_progress(tdata->prg, ++tdata->seen);
 933}
 934
 935static void test_show_commit(struct commit *commit, void *data)
 936{
 937        struct bitmap_test_data *tdata = data;
 938        int bitmap_pos;
 939
 940        bitmap_pos = bitmap_position(tdata->bitmap_git,
 941                                     &commit->object.oid);
 942        if (bitmap_pos < 0)
 943                die("Object not in bitmap: %s\n", oid_to_hex(&commit->object.oid));
 944
 945        bitmap_set(tdata->base, bitmap_pos);
 946        display_progress(tdata->prg, ++tdata->seen);
 947}
 948
 949void test_bitmap_walk(struct rev_info *revs)
 950{
 951        struct object *root;
 952        struct bitmap *result = NULL;
 953        khiter_t pos;
 954        size_t result_popcnt;
 955        struct bitmap_test_data tdata;
 956        struct bitmap_index *bitmap_git;
 957
 958        if (!(bitmap_git = prepare_bitmap_git(revs->repo)))
 959                die("failed to load bitmap indexes");
 960
 961        if (revs->pending.nr != 1)
 962                die("you must specify exactly one commit to test");
 963
 964        fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
 965                bitmap_git->version, bitmap_git->entry_count);
 966
 967        root = revs->pending.objects[0].item;
 968        pos = kh_get_oid_map(bitmap_git->bitmaps, root->oid);
 969
 970        if (pos < kh_end(bitmap_git->bitmaps)) {
 971                struct stored_bitmap *st = kh_value(bitmap_git->bitmaps, pos);
 972                struct ewah_bitmap *bm = lookup_stored_bitmap(st);
 973
 974                fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
 975                        oid_to_hex(&root->oid), (int)bm->bit_size, ewah_checksum(bm));
 976
 977                result = ewah_to_bitmap(bm);
 978        }
 979
 980        if (result == NULL)
 981                die("Commit %s doesn't have an indexed bitmap", oid_to_hex(&root->oid));
 982
 983        revs->tag_objects = 1;
 984        revs->tree_objects = 1;
 985        revs->blob_objects = 1;
 986
 987        result_popcnt = bitmap_popcount(result);
 988
 989        if (prepare_revision_walk(revs))
 990                die("revision walk setup failed");
 991
 992        tdata.bitmap_git = bitmap_git;
 993        tdata.base = bitmap_new();
 994        tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
 995        tdata.seen = 0;
 996
 997        traverse_commit_list(revs, &test_show_commit, &test_show_object, &tdata);
 998
 999        stop_progress(&tdata.prg);
1000
1001        if (bitmap_equals(result, tdata.base))
1002                fprintf(stderr, "OK!\n");
1003        else
1004                fprintf(stderr, "Mismatch!\n");
1005
1006        free_bitmap_index(bitmap_git);
1007}
1008
1009static int rebuild_bitmap(uint32_t *reposition,
1010                          struct ewah_bitmap *source,
1011                          struct bitmap *dest)
1012{
1013        uint32_t pos = 0;
1014        struct ewah_iterator it;
1015        eword_t word;
1016
1017        ewah_iterator_init(&it, source);
1018
1019        while (ewah_iterator_next(&word, &it)) {
1020                uint32_t offset, bit_pos;
1021
1022                for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
1023                        if ((word >> offset) == 0)
1024                                break;
1025
1026                        offset += ewah_bit_ctz64(word >> offset);
1027
1028                        bit_pos = reposition[pos + offset];
1029                        if (bit_pos > 0)
1030                                bitmap_set(dest, bit_pos - 1);
1031                        else /* can't reuse, we don't have the object */
1032                                return -1;
1033                }
1034
1035                pos += BITS_IN_EWORD;
1036        }
1037        return 0;
1038}
1039
1040int rebuild_existing_bitmaps(struct bitmap_index *bitmap_git,
1041                             struct packing_data *mapping,
1042                             kh_oid_map_t *reused_bitmaps,
1043                             int show_progress)
1044{
1045        uint32_t i, num_objects;
1046        uint32_t *reposition;
1047        struct bitmap *rebuild;
1048        struct stored_bitmap *stored;
1049        struct progress *progress = NULL;
1050
1051        khiter_t hash_pos;
1052        int hash_ret;
1053
1054        num_objects = bitmap_git->pack->num_objects;
1055        reposition = xcalloc(num_objects, sizeof(uint32_t));
1056
1057        for (i = 0; i < num_objects; ++i) {
1058                struct object_id oid;
1059                struct revindex_entry *entry;
1060                struct object_entry *oe;
1061
1062                entry = &bitmap_git->pack->revindex[i];
1063                nth_packed_object_oid(&oid, bitmap_git->pack, entry->nr);
1064                oe = packlist_find(mapping, &oid);
1065
1066                if (oe)
1067                        reposition[i] = oe_in_pack_pos(mapping, oe) + 1;
1068        }
1069
1070        rebuild = bitmap_new();
1071        i = 0;
1072
1073        if (show_progress)
1074                progress = start_progress("Reusing bitmaps", 0);
1075
1076        kh_foreach_value(bitmap_git->bitmaps, stored, {
1077                if (stored->flags & BITMAP_FLAG_REUSE) {
1078                        if (!rebuild_bitmap(reposition,
1079                                            lookup_stored_bitmap(stored),
1080                                            rebuild)) {
1081                                hash_pos = kh_put_oid_map(reused_bitmaps,
1082                                                          stored->oid,
1083                                                          &hash_ret);
1084                                kh_value(reused_bitmaps, hash_pos) =
1085                                        bitmap_to_ewah(rebuild);
1086                        }
1087                        bitmap_reset(rebuild);
1088                        display_progress(progress, ++i);
1089                }
1090        });
1091
1092        stop_progress(&progress);
1093
1094        free(reposition);
1095        bitmap_free(rebuild);
1096        return 0;
1097}
1098
1099void free_bitmap_index(struct bitmap_index *b)
1100{
1101        if (!b)
1102                return;
1103
1104        if (b->map)
1105                munmap(b->map, b->map_size);
1106        ewah_pool_free(b->commits);
1107        ewah_pool_free(b->trees);
1108        ewah_pool_free(b->blobs);
1109        ewah_pool_free(b->tags);
1110        kh_destroy_oid_map(b->bitmaps);
1111        free(b->ext_index.objects);
1112        free(b->ext_index.hashes);
1113        bitmap_free(b->result);
1114        bitmap_free(b->haves);
1115        free(b);
1116}
1117
1118int bitmap_has_oid_in_uninteresting(struct bitmap_index *bitmap_git,
1119                                    const struct object_id *oid)
1120{
1121        int pos;
1122
1123        if (!bitmap_git)
1124                return 0; /* no bitmap loaded */
1125        if (!bitmap_git->haves)
1126                return 0; /* walk had no "haves" */
1127
1128        pos = bitmap_position_packfile(bitmap_git, oid);
1129        if (pos < 0)
1130                return 0;
1131
1132        return bitmap_get(bitmap_git->haves, pos);
1133}