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