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