shallow.c

   1 #include "cache.h"
   2 #include "repository.h"
   3 #include "tempfile.h"
   4 #include "lockfile.h"
   5 #include "object-store.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "pkt-line.h"
   9 #include "remote.h"
  10 #include "refs.h"
  11 #include "sha1-array.h"
  12 #include "diff.h"
  13 #include "revision.h"
  14 #include "commit-slab.h"
  15 #include "revision.h"
  16 #include "list-objects.h"
  17 #include "commit-slab.h"
  18 #include "repository.h"
  19 #include "commit-reach.h"
  20
  21 void set_alternate_shallow_file(struct repository *r, const char *path, int override)
  22 {
  23         if (r->parsed_objects->is_shallow != -1)
  24                 BUG("is_repository_shallow must not be called before set_alternate_shallow_file");
  25         if (r->parsed_objects->alternate_shallow_file && !override)
  26                 return;
  27         free(r->parsed_objects->alternate_shallow_file);
  28         r->parsed_objects->alternate_shallow_file = xstrdup_or_null(path);
  29 }
  30
  31 int register_shallow(struct repository *r, const struct object_id *oid)
  32 {
  33         struct commit_graft *graft =
  34                 xmalloc(sizeof(struct commit_graft));
  35         struct commit *commit = lookup_commit(the_repository, oid);
  36
  37         oidcpy(&graft->oid, oid);
  38         graft->nr_parent = -1;
  39         if (commit && commit->object.parsed)
  40                 commit->parents = NULL;
  41         return register_commit_graft(r, graft, 0);
  42 }
  43
  44 int is_repository_shallow(struct repository *r)
  45 {
  46         /*
  47          * NEEDSWORK: This function updates
  48          * r->parsed_objects->{is_shallow,shallow_stat} as a side effect but
  49          * there is no corresponding function to clear them when the shallow
  50          * file is updated.
  51          */
  52
  53         FILE *fp;
  54         char buf[1024];
  55         const char *path = r->parsed_objects->alternate_shallow_file;
  56
  57         if (r->parsed_objects->is_shallow >= 0)
  58                 return r->parsed_objects->is_shallow;
  59
  60         if (!path)
  61                 path = git_path_shallow(r);
  62         /*
  63          * fetch-pack sets '--shallow-file ""' as an indicator that no
  64          * shallow file should be used. We could just open it and it
  65          * will likely fail. But let's do an explicit check instead.
  66          */
  67         if (!*path || (fp = fopen(path, "r")) == NULL) {
  68                 stat_validity_clear(r->parsed_objects->shallow_stat);
  69                 r->parsed_objects->is_shallow = 0;
  70                 return r->parsed_objects->is_shallow;
  71         }
  72         stat_validity_update(r->parsed_objects->shallow_stat, fileno(fp));
  73         r->parsed_objects->is_shallow = 1;
  74
  75         while (fgets(buf, sizeof(buf), fp)) {
  76                 struct object_id oid;
  77                 if (get_oid_hex(buf, &oid))
  78                         die("bad shallow line: %s", buf);
  79                 register_shallow(r, &oid);
  80         }
  81         fclose(fp);
  82         return r->parsed_objects->is_shallow;
  83 }
  84
  85 /*
  86  * TODO: use "int" elemtype instead of "int *" when/if commit-slab
  87  * supports a "valid" flag.
  88  */
  89 define_commit_slab(commit_depth, int *);
  90 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
  91                 int shallow_flag, int not_shallow_flag)
  92 {
  93         int i = 0, cur_depth = 0;
  94         struct commit_list *result = NULL;
  95         struct object_array stack = OBJECT_ARRAY_INIT;
  96         struct commit *commit = NULL;
  97         struct commit_graft *graft;
  98         struct commit_depth depths;
  99
 100         init_commit_depth(&depths);
 101         while (commit || i < heads->nr || stack.nr) {
 102                 struct commit_list *p;
 103                 if (!commit) {
 104                         if (i < heads->nr) {
 105                                 int **depth_slot;
 106                                 commit = (struct commit *)
 107                                         deref_tag(the_repository,
 108                                                   heads->objects[i++].item,
 109                                                   NULL, 0);
 110                                 if (!commit || commit->object.type != OBJ_COMMIT) {
 111                                         commit = NULL;
 112                                         continue;
 113                                 }
 114                                 depth_slot = commit_depth_at(&depths, commit);
 115                                 if (!*depth_slot)
 116                                         *depth_slot = xmalloc(sizeof(int));
 117                                 **depth_slot = 0;
 118                                 cur_depth = 0;
 119                         } else {
 120                                 commit = (struct commit *)
 121                                         object_array_pop(&stack);
 122                                 cur_depth = **commit_depth_at(&depths, commit);
 123                         }
 124                 }
 125                 parse_commit_or_die(commit);
 126                 cur_depth++;
 127                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
 128                     (is_repository_shallow(the_repository) && !commit->parents &&
 129                      (graft = lookup_commit_graft(the_repository, &commit->object.oid)) != NULL &&
 130                      graft->nr_parent < 0)) {
 131                         commit_list_insert(commit, &result);
 132                         commit->object.flags |= shallow_flag;
 133                         commit = NULL;
 134                         continue;
 135                 }
 136                 commit->object.flags |= not_shallow_flag;
 137                 for (p = commit->parents, commit = NULL; p; p = p->next) {
 138                         int **depth_slot = commit_depth_at(&depths, p->item);
 139                         if (!*depth_slot) {
 140                                 *depth_slot = xmalloc(sizeof(int));
 141                                 **depth_slot = cur_depth;
 142                         } else {
 143                                 if (cur_depth >= **depth_slot)
 144                                         continue;
 145                                 **depth_slot = cur_depth;
 146                         }
 147                         if (p->next)
 148                                 add_object_array(&p->item->object,
 149                                                 NULL, &stack);
 150                         else {
 151                                 commit = p->item;
 152                                 cur_depth = **commit_depth_at(&depths, commit);
 153                         }
 154                 }
 155         }
 156         for (i = 0; i < depths.slab_count; i++) {
 157                 int j;
 158
 159                 if (!depths.slab[i])
 160                         continue;
 161                 for (j = 0; j < depths.slab_size; j++)
 162                         free(depths.slab[i][j]);
 163         }
 164         clear_commit_depth(&depths);
 165
 166         return result;
 167 }
 168
 169 static void show_commit(struct commit *commit, void *data)
 170 {
 171         commit_list_insert(commit, data);
 172 }
 173
 174 /*
 175  * Given rev-list arguments, run rev-list. All reachable commits
 176  * except border ones are marked with not_shallow_flag. Border commits
 177  * are marked with shallow_flag. The list of border/shallow commits
 178  * are also returned.
 179  */
 180 struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av,
 181                                                     int shallow_flag,
 182                                                     int not_shallow_flag)
 183 {
 184         struct commit_list *result = NULL, *p;
 185         struct commit_list *not_shallow_list = NULL;
 186         struct rev_info revs;
 187         int both_flags = shallow_flag | not_shallow_flag;
 188
 189         /*
 190          * SHALLOW (excluded) and NOT_SHALLOW (included) should not be
 191          * set at this point. But better be safe than sorry.
 192          */
 193         clear_object_flags(both_flags);
 194
 195         is_repository_shallow(the_repository); /* make sure shallows are read */
 196
 197         repo_init_revisions(the_repository, &revs, NULL);
 198         save_commit_buffer = 0;
 199         setup_revisions(ac, av, &revs, NULL);
 200
 201         if (prepare_revision_walk(&revs))
 202                 die("revision walk setup failed");
 203         traverse_commit_list(&revs, show_commit, NULL, &not_shallow_list);
 204
 205         if (!not_shallow_list)
 206                 die("no commits selected for shallow requests");
 207
 208         /* Mark all reachable commits as NOT_SHALLOW */
 209         for (p = not_shallow_list; p; p = p->next)
 210                 p->item->object.flags |= not_shallow_flag;
 211
 212         /*
 213          * mark border commits SHALLOW + NOT_SHALLOW.
 214          * We cannot clear NOT_SHALLOW right now. Imagine border
 215          * commit A is processed first, then commit B, whose parent is
 216          * A, later. If NOT_SHALLOW on A is cleared at step 1, B
 217          * itself is considered border at step 2, which is incorrect.
 218          */
 219         for (p = not_shallow_list; p; p = p->next) {
 220                 struct commit *c = p->item;
 221                 struct commit_list *parent;
 222
 223                 if (parse_commit(c))
 224                         die("unable to parse commit %s",
 225                             oid_to_hex(&c->object.oid));
 226
 227                 for (parent = c->parents; parent; parent = parent->next)
 228                         if (!(parent->item->object.flags & not_shallow_flag)) {
 229                                 c->object.flags |= shallow_flag;
 230                                 commit_list_insert(c, &result);
 231                                 break;
 232                         }
 233         }
 234         free_commit_list(not_shallow_list);
 235
 236         /*
 237          * Now we can clean up NOT_SHALLOW on border commits. Having
 238          * both flags set can confuse the caller.
 239          */
 240         for (p = result; p; p = p->next) {
 241                 struct object *o = &p->item->object;
 242                 if ((o->flags & both_flags) == both_flags)
 243                         o->flags &= ~not_shallow_flag;
 244         }
 245         return result;
 246 }
 247
 248 static void check_shallow_file_for_update(struct repository *r)
 249 {
 250         if (r->parsed_objects->is_shallow == -1)
 251                 BUG("shallow must be initialized by now");
 252
 253         if (!stat_validity_check(r->parsed_objects->shallow_stat,
 254                                  git_path_shallow(r)))
 255                 die("shallow file has changed since we read it");
 256 }
 257
 258 #define SEEN_ONLY 1
 259 #define VERBOSE   2
 260 #define QUICK 4
 261
 262 struct write_shallow_data {
 263         struct strbuf *out;
 264         int use_pack_protocol;
 265         int count;
 266         unsigned flags;
 267 };
 268
 269 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 270 {
 271         struct write_shallow_data *data = cb_data;
 272         const char *hex = oid_to_hex(&graft->oid);
 273         if (graft->nr_parent != -1)
 274                 return 0;
 275         if (data->flags & QUICK) {
 276                 if (!has_object_file(&graft->oid))
 277                         return 0;
 278         } else if (data->flags & SEEN_ONLY) {
 279                 struct commit *c = lookup_commit(the_repository, &graft->oid);
 280                 if (!c || !(c->object.flags & SEEN)) {
 281                         if (data->flags & VERBOSE)
 282                                 printf("Removing %s from .git/shallow\n",
 283                                        oid_to_hex(&c->object.oid));
 284                         return 0;
 285                 }
 286         }
 287         data->count++;
 288         if (data->use_pack_protocol)
 289                 packet_buf_write(data->out, "shallow %s", hex);
 290         else {
 291                 strbuf_addstr(data->out, hex);
 292                 strbuf_addch(data->out, '\n');
 293         }
 294         return 0;
 295 }
 296
 297 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
 298                                    const struct oid_array *extra,
 299                                    unsigned flags)
 300 {
 301         struct write_shallow_data data;
 302         int i;
 303         data.out = out;
 304         data.use_pack_protocol = use_pack_protocol;
 305         data.count = 0;
 306         data.flags = flags;
 307         for_each_commit_graft(write_one_shallow, &data);
 308         if (!extra)
 309                 return data.count;
 310         for (i = 0; i < extra->nr; i++) {
 311                 strbuf_addstr(out, oid_to_hex(extra->oid + i));
 312                 strbuf_addch(out, '\n');
 313                 data.count++;
 314         }
 315         return data.count;
 316 }
 317
 318 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
 319                           const struct oid_array *extra)
 320 {
 321         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
 322 }
 323
 324 const char *setup_temporary_shallow(const struct oid_array *extra)
 325 {
 326         struct tempfile *temp;
 327         struct strbuf sb = STRBUF_INIT;
 328
 329         if (write_shallow_commits(&sb, 0, extra)) {
 330                 temp = xmks_tempfile(git_path("shallow_XXXXXX"));
 331
 332                 if (write_in_full(temp->fd, sb.buf, sb.len) < 0 ||
 333                     close_tempfile_gently(temp) < 0)
 334                         die_errno("failed to write to %s",
 335                                   get_tempfile_path(temp));
 336                 strbuf_release(&sb);
 337                 return get_tempfile_path(temp);
 338         }
 339         /*
 340          * is_repository_shallow() sees empty string as "no shallow
 341          * file".
 342          */
 343         return "";
 344 }
 345
 346 void setup_alternate_shallow(struct lock_file *shallow_lock,
 347                              const char **alternate_shallow_file,
 348                              const struct oid_array *extra)
 349 {
 350         struct strbuf sb = STRBUF_INIT;
 351         int fd;
 352
 353         fd = hold_lock_file_for_update(shallow_lock,
 354                                        git_path_shallow(the_repository),
 355                                        LOCK_DIE_ON_ERROR);
 356         check_shallow_file_for_update(the_repository);
 357         if (write_shallow_commits(&sb, 0, extra)) {
 358                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 359                         die_errno("failed to write to %s",
 360                                   get_lock_file_path(shallow_lock));
 361                 *alternate_shallow_file = get_lock_file_path(shallow_lock);
 362         } else
 363                 /*
 364                  * is_repository_shallow() sees empty string as "no
 365                  * shallow file".
 366                  */
 367                 *alternate_shallow_file = "";
 368         strbuf_release(&sb);
 369 }
 370
 371 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
 372 {
 373         int fd = *(int *)cb;
 374         if (graft->nr_parent == -1)
 375                 packet_write_fmt(fd, "shallow %s\n", oid_to_hex(&graft->oid));
 376         return 0;
 377 }
 378
 379 void advertise_shallow_grafts(int fd)
 380 {
 381         if (!is_repository_shallow(the_repository))
 382                 return;
 383         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
 384 }
 385
 386 /*
 387  * mark_reachable_objects() should have been run prior to this and all
 388  * reachable commits marked as "SEEN", except when quick_prune is non-zero,
 389  * in which case lines are excised from the shallow file if they refer to
 390  * commits that do not exist (any longer).
 391  */
 392 void prune_shallow(unsigned options)
 393 {
 394         struct lock_file shallow_lock = LOCK_INIT;
 395         struct strbuf sb = STRBUF_INIT;
 396         unsigned flags = SEEN_ONLY;
 397         int fd;
 398
 399         if (options & PRUNE_QUICK)
 400                 flags |= QUICK;
 401
 402         if (options & PRUNE_SHOW_ONLY) {
 403                 flags |= VERBOSE;
 404                 write_shallow_commits_1(&sb, 0, NULL, flags);
 405                 strbuf_release(&sb);
 406                 return;
 407         }
 408         fd = hold_lock_file_for_update(&shallow_lock,
 409                                        git_path_shallow(the_repository),
 410                                        LOCK_DIE_ON_ERROR);
 411         check_shallow_file_for_update(the_repository);
 412         if (write_shallow_commits_1(&sb, 0, NULL, flags)) {
 413                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 414                         die_errno("failed to write to %s",
 415                                   get_lock_file_path(&shallow_lock));
 416                 commit_lock_file(&shallow_lock);
 417         } else {
 418                 unlink(git_path_shallow(the_repository));
 419                 rollback_lock_file(&shallow_lock);
 420         }
 421         strbuf_release(&sb);
 422 }
 423
 424 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
 425
 426 /*
 427  * Step 1, split sender shallow commits into "ours" and "theirs"
 428  * Step 2, clean "ours" based on .git/shallow
 429  */
 430 void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa)
 431 {
 432         int i;
 433         trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
 434         memset(info, 0, sizeof(*info));
 435         info->shallow = sa;
 436         if (!sa)
 437                 return;
 438         ALLOC_ARRAY(info->ours, sa->nr);
 439         ALLOC_ARRAY(info->theirs, sa->nr);
 440         for (i = 0; i < sa->nr; i++) {
 441                 if (has_object_file(sa->oid + i)) {
 442                         struct commit_graft *graft;
 443                         graft = lookup_commit_graft(the_repository,
 444                                                     &sa->oid[i]);
 445                         if (graft && graft->nr_parent < 0)
 446                                 continue;
 447                         info->ours[info->nr_ours++] = i;
 448                 } else
 449                         info->theirs[info->nr_theirs++] = i;
 450         }
 451 }
 452
 453 void clear_shallow_info(struct shallow_info *info)
 454 {
 455         free(info->ours);
 456         free(info->theirs);
 457 }
 458
 459 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
 460
 461 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 462 {
 463         struct object_id *oid = info->shallow->oid;
 464         int i, dst;
 465         trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
 466         for (i = dst = 0; i < info->nr_theirs; i++) {
 467                 if (i != dst)
 468                         info->theirs[dst] = info->theirs[i];
 469                 if (has_object_file(oid + info->theirs[i]))
 470                         dst++;
 471         }
 472         info->nr_theirs = dst;
 473 }
 474
 475 define_commit_slab(ref_bitmap, uint32_t *);
 476
 477 #define POOL_SIZE (512 * 1024)
 478
 479 struct paint_info {
 480         struct ref_bitmap ref_bitmap;
 481         unsigned nr_bits;
 482         char **pools;
 483         char *free, *end;
 484         unsigned pool_count;
 485 };
 486
 487 static uint32_t *paint_alloc(struct paint_info *info)
 488 {
 489         unsigned nr = DIV_ROUND_UP(info->nr_bits, 32);
 490         unsigned size = nr * sizeof(uint32_t);
 491         void *p;
 492         if (!info->pool_count || size > info->end - info->free) {
 493                 if (size > POOL_SIZE)
 494                         BUG("pool size too small for %d in paint_alloc()",
 495                             size);
 496                 info->pool_count++;
 497                 REALLOC_ARRAY(info->pools, info->pool_count);
 498                 info->free = xmalloc(POOL_SIZE);
 499                 info->pools[info->pool_count - 1] = info->free;
 500                 info->end = info->free + POOL_SIZE;
 501         }
 502         p = info->free;
 503         info->free += size;
 504         return p;
 505 }
 506
 507 /*
 508  * Given a commit SHA-1, walk down to parents until either SEEN,
 509  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
 510  * all walked commits.
 511  */
 512 static void paint_down(struct paint_info *info, const struct object_id *oid,
 513                        unsigned int id)
 514 {
 515         unsigned int i, nr;
 516         struct commit_list *head = NULL;
 517         int bitmap_nr = DIV_ROUND_UP(info->nr_bits, 32);
 518         size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
 519         struct commit *c = lookup_commit_reference_gently(the_repository, oid,
 520                                                           1);
 521         uint32_t *tmp; /* to be freed before return */
 522         uint32_t *bitmap;
 523
 524         if (!c)
 525                 return;
 526
 527         tmp = xmalloc(bitmap_size);
 528         bitmap = paint_alloc(info);
 529         memset(bitmap, 0, bitmap_size);
 530         bitmap[id / 32] |= (1U << (id % 32));
 531         commit_list_insert(c, &head);
 532         while (head) {
 533                 struct commit_list *p;
 534                 struct commit *c = pop_commit(&head);
 535                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 536
 537                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
 538                 if (c->object.flags & (SEEN | UNINTERESTING))
 539                         continue;
 540                 else
 541                         c->object.flags |= SEEN;
 542
 543                 if (*refs == NULL)
 544                         *refs = bitmap;
 545                 else {
 546                         memcpy(tmp, *refs, bitmap_size);
 547                         for (i = 0; i < bitmap_nr; i++)
 548                                 tmp[i] |= bitmap[i];
 549                         if (memcmp(tmp, *refs, bitmap_size)) {
 550                                 *refs = paint_alloc(info);
 551                                 memcpy(*refs, tmp, bitmap_size);
 552                         }
 553                 }
 554
 555                 if (c->object.flags & BOTTOM)
 556                         continue;
 557
 558                 if (parse_commit(c))
 559                         die("unable to parse commit %s",
 560                             oid_to_hex(&c->object.oid));
 561
 562                 for (p = c->parents; p; p = p->next) {
 563                         if (p->item->object.flags & SEEN)
 564                                 continue;
 565                         commit_list_insert(p->item, &head);
 566                 }
 567         }
 568
 569         nr = get_max_object_index();
 570         for (i = 0; i < nr; i++) {
 571                 struct object *o = get_indexed_object(i);
 572                 if (o && o->type == OBJ_COMMIT)
 573                         o->flags &= ~SEEN;
 574         }
 575
 576         free(tmp);
 577 }
 578
 579 static int mark_uninteresting(const char *refname, const struct object_id *oid,
 580                               int flags, void *cb_data)
 581 {
 582         struct commit *commit = lookup_commit_reference_gently(the_repository,
 583                                                                oid, 1);
 584         if (!commit)
 585                 return 0;
 586         commit->object.flags |= UNINTERESTING;
 587         mark_parents_uninteresting(commit);
 588         return 0;
 589 }
 590
 591 static void post_assign_shallow(struct shallow_info *info,
 592                                 struct ref_bitmap *ref_bitmap,
 593                                 int *ref_status);
 594 /*
 595  * Step 6(+7), associate shallow commits with new refs
 596  *
 597  * info->ref must be initialized before calling this function.
 598  *
 599  * If used is not NULL, it's an array of info->shallow->nr
 600  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
 601  * m-th shallow commit from info->shallow.
 602  *
 603  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
 604  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
 605  * the ref needs some shallow commits from either info->ours or
 606  * info->theirs.
 607  */
 608 void assign_shallow_commits_to_refs(struct shallow_info *info,
 609                                     uint32_t **used, int *ref_status)
 610 {
 611         struct object_id *oid = info->shallow->oid;
 612         struct oid_array *ref = info->ref;
 613         unsigned int i, nr;
 614         int *shallow, nr_shallow = 0;
 615         struct paint_info pi;
 616
 617         trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
 618         ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs);
 619         for (i = 0; i < info->nr_ours; i++)
 620                 shallow[nr_shallow++] = info->ours[i];
 621         for (i = 0; i < info->nr_theirs; i++)
 622                 shallow[nr_shallow++] = info->theirs[i];
 623
 624         /*
 625          * Prepare the commit graph to track what refs can reach what
 626          * (new) shallow commits.
 627          */
 628         nr = get_max_object_index();
 629         for (i = 0; i < nr; i++) {
 630                 struct object *o = get_indexed_object(i);
 631                 if (!o || o->type != OBJ_COMMIT)
 632                         continue;
 633
 634                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
 635         }
 636
 637         memset(&pi, 0, sizeof(pi));
 638         init_ref_bitmap(&pi.ref_bitmap);
 639         pi.nr_bits = ref->nr;
 640
 641         /*
 642          * "--not --all" to cut short the traversal if new refs
 643          * connect to old refs. If not (e.g. force ref updates) it'll
 644          * have to go down to the current shallow commits.
 645          */
 646         head_ref(mark_uninteresting, NULL);
 647         for_each_ref(mark_uninteresting, NULL);
 648
 649         /* Mark potential bottoms so we won't go out of bound */
 650         for (i = 0; i < nr_shallow; i++) {
 651                 struct commit *c = lookup_commit(the_repository,
 652                                                  &oid[shallow[i]]);
 653                 c->object.flags |= BOTTOM;
 654         }
 655
 656         for (i = 0; i < ref->nr; i++)
 657                 paint_down(&pi, ref->oid + i, i);
 658
 659         if (used) {
 660                 int bitmap_size = DIV_ROUND_UP(pi.nr_bits, 32) * sizeof(uint32_t);
 661                 memset(used, 0, sizeof(*used) * info->shallow->nr);
 662                 for (i = 0; i < nr_shallow; i++) {
 663                         const struct commit *c = lookup_commit(the_repository,
 664                                                                &oid[shallow[i]]);
 665                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 666                         if (*map)
 667                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
 668                 }
 669                 /*
 670                  * unreachable shallow commits are not removed from
 671                  * "ours" and "theirs". The user is supposed to run
 672                  * step 7 on every ref separately and not trust "ours"
 673                  * and "theirs" any more.
 674                  */
 675         } else
 676                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
 677
 678         clear_ref_bitmap(&pi.ref_bitmap);
 679         for (i = 0; i < pi.pool_count; i++)
 680                 free(pi.pools[i]);
 681         free(pi.pools);
 682         free(shallow);
 683 }
 684
 685 struct commit_array {
 686         struct commit **commits;
 687         int nr, alloc;
 688 };
 689
 690 static int add_ref(const char *refname, const struct object_id *oid,
 691                    int flags, void *cb_data)
 692 {
 693         struct commit_array *ca = cb_data;
 694         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
 695         ca->commits[ca->nr] = lookup_commit_reference_gently(the_repository,
 696                                                              oid, 1);
 697         if (ca->commits[ca->nr])
 698                 ca->nr++;
 699         return 0;
 700 }
 701
 702 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
 703 {
 704         unsigned int i;
 705         if (!ref_status)
 706                 return;
 707         for (i = 0; i < nr; i++)
 708                 if (bitmap[i / 32] & (1U << (i % 32)))
 709                         ref_status[i]++;
 710 }
 711
 712 /*
 713  * Step 7, reachability test on "ours" at commit level
 714  */
 715 static void post_assign_shallow(struct shallow_info *info,
 716                                 struct ref_bitmap *ref_bitmap,
 717                                 int *ref_status)
 718 {
 719         struct object_id *oid = info->shallow->oid;
 720         struct commit *c;
 721         uint32_t **bitmap;
 722         int dst, i, j;
 723         int bitmap_nr = DIV_ROUND_UP(info->ref->nr, 32);
 724         struct commit_array ca;
 725
 726         trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
 727         if (ref_status)
 728                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
 729
 730         /* Remove unreachable shallow commits from "theirs" */
 731         for (i = dst = 0; i < info->nr_theirs; i++) {
 732                 if (i != dst)
 733                         info->theirs[dst] = info->theirs[i];
 734                 c = lookup_commit(the_repository, &oid[info->theirs[i]]);
 735                 bitmap = ref_bitmap_at(ref_bitmap, c);
 736                 if (!*bitmap)
 737                         continue;
 738                 for (j = 0; j < bitmap_nr; j++)
 739                         if (bitmap[0][j]) {
 740                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 741                                 dst++;
 742                                 break;
 743                         }
 744         }
 745         info->nr_theirs = dst;
 746
 747         memset(&ca, 0, sizeof(ca));
 748         head_ref(add_ref, &ca);
 749         for_each_ref(add_ref, &ca);
 750
 751         /* Remove unreachable shallow commits from "ours" */
 752         for (i = dst = 0; i < info->nr_ours; i++) {
 753                 if (i != dst)
 754                         info->ours[dst] = info->ours[i];
 755                 c = lookup_commit(the_repository, &oid[info->ours[i]]);
 756                 bitmap = ref_bitmap_at(ref_bitmap, c);
 757                 if (!*bitmap)
 758                         continue;
 759                 for (j = 0; j < bitmap_nr; j++)
 760                         if (bitmap[0][j] &&
 761                             /* Step 7, reachability test at commit level */
 762                             !in_merge_bases_many(c, ca.nr, ca.commits)) {
 763                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 764                                 dst++;
 765                                 break;
 766                         }
 767         }
 768         info->nr_ours = dst;
 769
 770         free(ca.commits);
 771 }
 772
 773 /* (Delayed) step 7, reachability test at commit level */
 774 int delayed_reachability_test(struct shallow_info *si, int c)
 775 {
 776         if (si->need_reachability_test[c]) {
 777                 struct commit *commit = lookup_commit(the_repository,
 778                                                       &si->shallow->oid[c]);
 779
 780                 if (!si->commits) {
 781                         struct commit_array ca;
 782
 783                         memset(&ca, 0, sizeof(ca));
 784                         head_ref(add_ref, &ca);
 785                         for_each_ref(add_ref, &ca);
 786                         si->commits = ca.commits;
 787                         si->nr_commits = ca.nr;
 788                 }
 789
 790                 si->reachable[c] = in_merge_bases_many(commit,
 791                                                        si->nr_commits,
 792                                                        si->commits);
 793                 si->need_reachability_test[c] = 0;
 794         }
 795         return si->reachable[c];
 796 }