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