git.oblomov.eu Git - git/blob - 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 "oid-array.h"
  12 #include "diff.h"
  13 #include "revision.h"
  14 #include "commit-slab.h"
  15 #include "list-objects.h"
  16 #include "commit-reach.h"
  17 #include "shallow.h"
  18
  19 void set_alternate_shallow_file(struct repository *r, const char *path, int override)
  20 {
  21         if (r->parsed_objects->is_shallow != -1)
  22                 BUG("is_repository_shallow must not be called before set_alternate_shallow_file");
  23         if (r->parsed_objects->alternate_shallow_file && !override)
  24                 return;
  25         free(r->parsed_objects->alternate_shallow_file);
  26         r->parsed_objects->alternate_shallow_file = xstrdup_or_null(path);
  27 }
  28
  29 int register_shallow(struct repository *r, const struct object_id *oid)
  30 {
  31         struct commit_graft *graft =
  32                 xmalloc(sizeof(struct commit_graft));
  33         struct commit *commit = lookup_commit(the_repository, oid);
  34
  35         oidcpy(&graft->oid, oid);
  36         graft->nr_parent = -1;
  37         if (commit && commit->object.parsed)
  38                 commit->parents = NULL;
  39         return register_commit_graft(r, graft, 0);
  40 }
  41
  42 int unregister_shallow(const struct object_id *oid)
  43 {
  44         int pos = commit_graft_pos(the_repository, oid->hash);
  45         if (pos < 0)
  46                 return -1;
  47         if (pos + 1 < the_repository->parsed_objects->grafts_nr)
  48                 MOVE_ARRAY(the_repository->parsed_objects->grafts + pos,
  49                            the_repository->parsed_objects->grafts + pos + 1,
  50                            the_repository->parsed_objects->grafts_nr - pos - 1);
  51         the_repository->parsed_objects->grafts_nr--;
  52         return 0;
  53 }
  54
  55 int is_repository_shallow(struct repository *r)
  56 {
  57         FILE *fp;
  58         char buf[1024];
  59         const char *path = r->parsed_objects->alternate_shallow_file;
  60
  61         if (r->parsed_objects->is_shallow >= 0)
  62                 return r->parsed_objects->is_shallow;
  63
  64         if (!path)
  65                 path = git_path_shallow(r);
  66         /*
  67          * fetch-pack sets '--shallow-file ""' as an indicator that no
  68          * shallow file should be used. We could just open it and it
  69          * will likely fail. But let's do an explicit check instead.
  70          */
  71         if (!*path || (fp = fopen(path, "r")) == NULL) {
  72                 stat_validity_clear(r->parsed_objects->shallow_stat);
  73                 r->parsed_objects->is_shallow = 0;
  74                 return r->parsed_objects->is_shallow;
  75         }
  76         stat_validity_update(r->parsed_objects->shallow_stat, fileno(fp));
  77         r->parsed_objects->is_shallow = 1;
  78
  79         while (fgets(buf, sizeof(buf), fp)) {
  80                 struct object_id oid;
  81                 if (get_oid_hex(buf, &oid))
  82                         die("bad shallow line: %s", buf);
  83                 register_shallow(r, &oid);
  84         }
  85         fclose(fp);
  86         return r->parsed_objects->is_shallow;
  87 }
  88
  89 static void reset_repository_shallow(struct repository *r)
  90 {
  91         r->parsed_objects->is_shallow = -1;
  92         stat_validity_clear(r->parsed_objects->shallow_stat);
  93 }
  94
  95 int commit_shallow_file(struct repository *r, struct shallow_lock *lk)
  96 {
  97         int res = commit_lock_file(&lk->lock);
  98         reset_repository_shallow(r);
  99         return res;
 100 }
 101
 102 void rollback_shallow_file(struct repository *r, struct shallow_lock *lk)
 103 {
 104         rollback_lock_file(&lk->lock);
 105         reset_repository_shallow(r);
 106 }
 107
 108 /*
 109  * TODO: use "int" elemtype instead of "int *" when/if commit-slab
 110  * supports a "valid" flag.
 111  */
 112 define_commit_slab(commit_depth, int *);
 113 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
 114                 int shallow_flag, int not_shallow_flag)
 115 {
 116         int i = 0, cur_depth = 0;
 117         struct commit_list *result = NULL;
 118         struct object_array stack = OBJECT_ARRAY_INIT;
 119         struct commit *commit = NULL;
 120         struct commit_graft *graft;
 121         struct commit_depth depths;
 122
 123         init_commit_depth(&depths);
 124         while (commit || i < heads->nr || stack.nr) {
 125                 struct commit_list *p;
 126                 if (!commit) {
 127                         if (i < heads->nr) {
 128                                 int **depth_slot;
 129                                 commit = (struct commit *)
 130                                         deref_tag(the_repository,
 131                                                   heads->objects[i++].item,
 132                                                   NULL, 0);
 133                                 if (!commit || commit->object.type != OBJ_COMMIT) {
 134                                         commit = NULL;
 135                                         continue;
 136                                 }
 137                                 depth_slot = commit_depth_at(&depths, commit);
 138                                 if (!*depth_slot)
 139                                         *depth_slot = xmalloc(sizeof(int));
 140                                 **depth_slot = 0;
 141                                 cur_depth = 0;
 142                         } else {
 143                                 commit = (struct commit *)
 144                                         object_array_pop(&stack);
 145                                 cur_depth = **commit_depth_at(&depths, commit);
 146                         }
 147                 }
 148                 parse_commit_or_die(commit);
 149                 cur_depth++;
 150                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
 151                     (is_repository_shallow(the_repository) && !commit->parents &&
 152                      (graft = lookup_commit_graft(the_repository, &commit->object.oid)) != NULL &&
 153                      graft->nr_parent < 0)) {
 154                         commit_list_insert(commit, &result);
 155                         commit->object.flags |= shallow_flag;
 156                         commit = NULL;
 157                         continue;
 158                 }
 159                 commit->object.flags |= not_shallow_flag;
 160                 for (p = commit->parents, commit = NULL; p; p = p->next) {
 161                         int **depth_slot = commit_depth_at(&depths, p->item);
 162                         if (!*depth_slot) {
 163                                 *depth_slot = xmalloc(sizeof(int));
 164                                 **depth_slot = cur_depth;
 165                         } else {
 166                                 if (cur_depth >= **depth_slot)
 167                                         continue;
 168                                 **depth_slot = cur_depth;
 169                         }
 170                         if (p->next)
 171                                 add_object_array(&p->item->object,
 172                                                 NULL, &stack);
 173                         else {
 174                                 commit = p->item;
 175                                 cur_depth = **commit_depth_at(&depths, commit);
 176                         }
 177                 }
 178         }
 179         for (i = 0; i < depths.slab_count; i++) {
 180                 int j;
 181
 182                 if (!depths.slab[i])
 183                         continue;
 184                 for (j = 0; j < depths.slab_size; j++)
 185                         free(depths.slab[i][j]);
 186         }
 187         clear_commit_depth(&depths);
 188
 189         return result;
 190 }
 191
 192 static void show_commit(struct commit *commit, void *data)
 193 {
 194         commit_list_insert(commit, data);
 195 }
 196
 197 /*
 198  * Given rev-list arguments, run rev-list. All reachable commits
 199  * except border ones are marked with not_shallow_flag. Border commits
 200  * are marked with shallow_flag. The list of border/shallow commits
 201  * are also returned.
 202  */
 203 struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av,
 204                                                     int shallow_flag,
 205                                                     int not_shallow_flag)
 206 {
 207         struct commit_list *result = NULL, *p;
 208         struct commit_list *not_shallow_list = NULL;
 209         struct rev_info revs;
 210         int both_flags = shallow_flag | not_shallow_flag;
 211
 212         /*
 213          * SHALLOW (excluded) and NOT_SHALLOW (included) should not be
 214          * set at this point. But better be safe than sorry.
 215          */
 216         clear_object_flags(both_flags);
 217
 218         is_repository_shallow(the_repository); /* make sure shallows are read */
 219
 220         repo_init_revisions(the_repository, &revs, NULL);
 221         save_commit_buffer = 0;
 222         setup_revisions(ac, av, &revs, NULL);
 223
 224         if (prepare_revision_walk(&revs))
 225                 die("revision walk setup failed");
 226         traverse_commit_list(&revs, show_commit, NULL, &not_shallow_list);
 227
 228         if (!not_shallow_list)
 229                 die("no commits selected for shallow requests");
 230
 231         /* Mark all reachable commits as NOT_SHALLOW */
 232         for (p = not_shallow_list; p; p = p->next)
 233                 p->item->object.flags |= not_shallow_flag;
 234
 235         /*
 236          * mark border commits SHALLOW + NOT_SHALLOW.
 237          * We cannot clear NOT_SHALLOW right now. Imagine border
 238          * commit A is processed first, then commit B, whose parent is
 239          * A, later. If NOT_SHALLOW on A is cleared at step 1, B
 240          * itself is considered border at step 2, which is incorrect.
 241          */
 242         for (p = not_shallow_list; p; p = p->next) {
 243                 struct commit *c = p->item;
 244                 struct commit_list *parent;
 245
 246                 if (parse_commit(c))
 247                         die("unable to parse commit %s",
 248                             oid_to_hex(&c->object.oid));
 249
 250                 for (parent = c->parents; parent; parent = parent->next)
 251                         if (!(parent->item->object.flags & not_shallow_flag)) {
 252                                 c->object.flags |= shallow_flag;
 253                                 commit_list_insert(c, &result);
 254                                 break;
 255                         }
 256         }
 257         free_commit_list(not_shallow_list);
 258
 259         /*
 260          * Now we can clean up NOT_SHALLOW on border commits. Having
 261          * both flags set can confuse the caller.
 262          */
 263         for (p = result; p; p = p->next) {
 264                 struct object *o = &p->item->object;
 265                 if ((o->flags & both_flags) == both_flags)
 266                         o->flags &= ~not_shallow_flag;
 267         }
 268         return result;
 269 }
 270
 271 static void check_shallow_file_for_update(struct repository *r)
 272 {
 273         if (r->parsed_objects->is_shallow == -1)
 274                 BUG("shallow must be initialized by now");
 275
 276         if (!stat_validity_check(r->parsed_objects->shallow_stat,
 277                                  git_path_shallow(r)))
 278                 die("shallow file has changed since we read it");
 279 }
 280
 281 #define SEEN_ONLY 1
 282 #define VERBOSE   2
 283 #define QUICK 4
 284
 285 struct write_shallow_data {
 286         struct strbuf *out;
 287         int use_pack_protocol;
 288         int count;
 289         unsigned flags;
 290 };
 291
 292 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 293 {
 294         struct write_shallow_data *data = cb_data;
 295         const char *hex = oid_to_hex(&graft->oid);
 296         if (graft->nr_parent != -1)
 297                 return 0;
 298         if (data->flags & QUICK) {
 299                 if (!has_object_file(&graft->oid))
 300                         return 0;
 301         } else if (data->flags & SEEN_ONLY) {
 302                 struct commit *c = lookup_commit(the_repository, &graft->oid);
 303                 if (!c || !(c->object.flags & SEEN)) {
 304                         if (data->flags & VERBOSE)
 305                                 printf("Removing %s from .git/shallow\n",
 306                                        oid_to_hex(&c->object.oid));
 307                         return 0;
 308                 }
 309         }
 310         data->count++;
 311         if (data->use_pack_protocol)
 312                 packet_buf_write(data->out, "shallow %s", hex);
 313         else {
 314                 strbuf_addstr(data->out, hex);
 315                 strbuf_addch(data->out, '\n');
 316         }
 317         return 0;
 318 }
 319
 320 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
 321                                    const struct oid_array *extra,
 322                                    unsigned flags)
 323 {
 324         struct write_shallow_data data;
 325         int i;
 326         data.out = out;
 327         data.use_pack_protocol = use_pack_protocol;
 328         data.count = 0;
 329         data.flags = flags;
 330         for_each_commit_graft(write_one_shallow, &data);
 331         if (!extra)
 332                 return data.count;
 333         for (i = 0; i < extra->nr; i++) {
 334                 strbuf_addstr(out, oid_to_hex(extra->oid + i));
 335                 strbuf_addch(out, '\n');
 336                 data.count++;
 337         }
 338         return data.count;
 339 }
 340
 341 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
 342                           const struct oid_array *extra)
 343 {
 344         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
 345 }
 346
 347 const char *setup_temporary_shallow(const struct oid_array *extra)
 348 {
 349         struct tempfile *temp;
 350         struct strbuf sb = STRBUF_INIT;
 351
 352         if (write_shallow_commits(&sb, 0, extra)) {
 353                 temp = xmks_tempfile(git_path("shallow_XXXXXX"));
 354
 355                 if (write_in_full(temp->fd, sb.buf, sb.len) < 0 ||
 356                     close_tempfile_gently(temp) < 0)
 357                         die_errno("failed to write to %s",
 358                                   get_tempfile_path(temp));
 359                 strbuf_release(&sb);
 360                 return get_tempfile_path(temp);
 361         }
 362         /*
 363          * is_repository_shallow() sees empty string as "no shallow
 364          * file".
 365          */
 366         return "";
 367 }
 368
 369 void setup_alternate_shallow(struct shallow_lock *shallow_lock,
 370                              const char **alternate_shallow_file,
 371                              const struct oid_array *extra)
 372 {
 373         struct strbuf sb = STRBUF_INIT;
 374         int fd;
 375
 376         fd = hold_lock_file_for_update(&shallow_lock->lock,
 377                                        git_path_shallow(the_repository),
 378                                        LOCK_DIE_ON_ERROR);
 379         check_shallow_file_for_update(the_repository);
 380         if (write_shallow_commits(&sb, 0, extra)) {
 381                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 382                         die_errno("failed to write to %s",
 383                                   get_lock_file_path(&shallow_lock->lock));
 384                 *alternate_shallow_file = get_lock_file_path(&shallow_lock->lock);
 385         } else
 386                 /*
 387                  * is_repository_shallow() sees empty string as "no
 388                  * shallow file".
 389                  */
 390                 *alternate_shallow_file = "";
 391         strbuf_release(&sb);
 392 }
 393
 394 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
 395 {
 396         int fd = *(int *)cb;
 397         if (graft->nr_parent == -1)
 398                 packet_write_fmt(fd, "shallow %s\n", oid_to_hex(&graft->oid));
 399         return 0;
 400 }
 401
 402 void advertise_shallow_grafts(int fd)
 403 {
 404         if (!is_repository_shallow(the_repository))
 405                 return;
 406         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
 407 }
 408
 409 /*
 410  * mark_reachable_objects() should have been run prior to this and all
 411  * reachable commits marked as "SEEN", except when quick_prune is non-zero,
 412  * in which case lines are excised from the shallow file if they refer to
 413  * commits that do not exist (any longer).
 414  */
 415 void prune_shallow(unsigned options)
 416 {
 417         struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
 418         struct strbuf sb = STRBUF_INIT;
 419         unsigned flags = SEEN_ONLY;
 420         int fd;
 421
 422         if (options & PRUNE_QUICK)
 423                 flags |= QUICK;
 424
 425         if (options & PRUNE_SHOW_ONLY) {
 426                 flags |= VERBOSE;
 427                 write_shallow_commits_1(&sb, 0, NULL, flags);
 428                 strbuf_release(&sb);
 429                 return;
 430         }
 431         fd = hold_lock_file_for_update(&shallow_lock.lock,
 432                                        git_path_shallow(the_repository),
 433                                        LOCK_DIE_ON_ERROR);
 434         check_shallow_file_for_update(the_repository);
 435         if (write_shallow_commits_1(&sb, 0, NULL, flags)) {
 436                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 437                         die_errno("failed to write to %s",
 438                                   get_lock_file_path(&shallow_lock.lock));
 439                 commit_shallow_file(the_repository, &shallow_lock);
 440         } else {
 441                 unlink(git_path_shallow(the_repository));
 442                 rollback_shallow_file(the_repository, &shallow_lock);
 443         }
 444         strbuf_release(&sb);
 445 }
 446
 447 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
 448
 449 /*
 450  * Step 1, split sender shallow commits into "ours" and "theirs"
 451  * Step 2, clean "ours" based on .git/shallow
 452  */
 453 void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa)
 454 {
 455         int i;
 456         trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
 457         memset(info, 0, sizeof(*info));
 458         info->shallow = sa;
 459         if (!sa)
 460                 return;
 461         ALLOC_ARRAY(info->ours, sa->nr);
 462         ALLOC_ARRAY(info->theirs, sa->nr);
 463         for (i = 0; i < sa->nr; i++) {
 464                 if (has_object_file(sa->oid + i)) {
 465                         struct commit_graft *graft;
 466                         graft = lookup_commit_graft(the_repository,
 467                                                     &sa->oid[i]);
 468                         if (graft && graft->nr_parent < 0)
 469                                 continue;
 470                         info->ours[info->nr_ours++] = i;
 471                 } else
 472                         info->theirs[info->nr_theirs++] = i;
 473         }
 474 }
 475
 476 void clear_shallow_info(struct shallow_info *info)
 477 {
 478         free(info->ours);
 479         free(info->theirs);
 480 }
 481
 482 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
 483
 484 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 485 {
 486         struct object_id *oid = info->shallow->oid;
 487         int i, dst;
 488         trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
 489         for (i = dst = 0; i < info->nr_theirs; i++) {
 490                 if (i != dst)
 491                         info->theirs[dst] = info->theirs[i];
 492                 if (has_object_file(oid + info->theirs[i]))
 493                         dst++;
 494         }
 495         info->nr_theirs = dst;
 496 }
 497
 498 define_commit_slab(ref_bitmap, uint32_t *);
 499
 500 #define POOL_SIZE (512 * 1024)
 501
 502 struct paint_info {
 503         struct ref_bitmap ref_bitmap;
 504         unsigned nr_bits;
 505         char **pools;
 506         char *free, *end;
 507         unsigned pool_count;
 508 };
 509
 510 static uint32_t *paint_alloc(struct paint_info *info)
 511 {
 512         unsigned nr = DIV_ROUND_UP(info->nr_bits, 32);
 513         unsigned size = nr * sizeof(uint32_t);
 514         void *p;
 515         if (!info->pool_count || size > info->end - info->free) {
 516                 if (size > POOL_SIZE)
 517                         BUG("pool size too small for %d in paint_alloc()",
 518                             size);
 519                 info->pool_count++;
 520                 REALLOC_ARRAY(info->pools, info->pool_count);
 521                 info->free = xmalloc(POOL_SIZE);
 522                 info->pools[info->pool_count - 1] = info->free;
 523                 info->end = info->free + POOL_SIZE;
 524         }
 525         p = info->free;
 526         info->free += size;
 527         return p;
 528 }
 529
 530 /*
 531  * Given a commit SHA-1, walk down to parents until either SEEN,
 532  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
 533  * all walked commits.
 534  */
 535 static void paint_down(struct paint_info *info, const struct object_id *oid,
 536                        unsigned int id)
 537 {
 538         unsigned int i, nr;
 539         struct commit_list *head = NULL;
 540         int bitmap_nr = DIV_ROUND_UP(info->nr_bits, 32);
 541         size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
 542         struct commit *c = lookup_commit_reference_gently(the_repository, oid,
 543                                                           1);
 544         uint32_t *tmp; /* to be freed before return */
 545         uint32_t *bitmap;
 546
 547         if (!c)
 548                 return;
 549
 550         tmp = xmalloc(bitmap_size);
 551         bitmap = paint_alloc(info);
 552         memset(bitmap, 0, bitmap_size);
 553         bitmap[id / 32] |= (1U << (id % 32));
 554         commit_list_insert(c, &head);
 555         while (head) {
 556                 struct commit_list *p;
 557                 struct commit *c = pop_commit(&head);
 558                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 559
 560                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
 561                 if (c->object.flags & (SEEN | UNINTERESTING))
 562                         continue;
 563                 else
 564                         c->object.flags |= SEEN;
 565
 566                 if (*refs == NULL)
 567                         *refs = bitmap;
 568                 else {
 569                         memcpy(tmp, *refs, bitmap_size);
 570                         for (i = 0; i < bitmap_nr; i++)
 571                                 tmp[i] |= bitmap[i];
 572                         if (memcmp(tmp, *refs, bitmap_size)) {
 573                                 *refs = paint_alloc(info);
 574                                 memcpy(*refs, tmp, bitmap_size);
 575                         }
 576                 }
 577
 578                 if (c->object.flags & BOTTOM)
 579                         continue;
 580
 581                 if (parse_commit(c))
 582                         die("unable to parse commit %s",
 583                             oid_to_hex(&c->object.oid));
 584
 585                 for (p = c->parents; p; p = p->next) {
 586                         if (p->item->object.flags & SEEN)
 587                                 continue;
 588                         commit_list_insert(p->item, &head);
 589                 }
 590         }
 591
 592         nr = get_max_object_index();
 593         for (i = 0; i < nr; i++) {
 594                 struct object *o = get_indexed_object(i);
 595                 if (o && o->type == OBJ_COMMIT)
 596                         o->flags &= ~SEEN;
 597         }
 598
 599         free(tmp);
 600 }
 601
 602 static int mark_uninteresting(const char *refname, const struct object_id *oid,
 603                               int flags, void *cb_data)
 604 {
 605         struct commit *commit = lookup_commit_reference_gently(the_repository,
 606                                                                oid, 1);
 607         if (!commit)
 608                 return 0;
 609         commit->object.flags |= UNINTERESTING;
 610         mark_parents_uninteresting(commit);
 611         return 0;
 612 }
 613
 614 static void post_assign_shallow(struct shallow_info *info,
 615                                 struct ref_bitmap *ref_bitmap,
 616                                 int *ref_status);
 617 /*
 618  * Step 6(+7), associate shallow commits with new refs
 619  *
 620  * info->ref must be initialized before calling this function.
 621  *
 622  * If used is not NULL, it's an array of info->shallow->nr
 623  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
 624  * m-th shallow commit from info->shallow.
 625  *
 626  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
 627  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
 628  * the ref needs some shallow commits from either info->ours or
 629  * info->theirs.
 630  */
 631 void assign_shallow_commits_to_refs(struct shallow_info *info,
 632                                     uint32_t **used, int *ref_status)
 633 {
 634         struct object_id *oid = info->shallow->oid;
 635         struct oid_array *ref = info->ref;
 636         unsigned int i, nr;
 637         int *shallow, nr_shallow = 0;
 638         struct paint_info pi;
 639
 640         trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
 641         ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs);
 642         for (i = 0; i < info->nr_ours; i++)
 643                 shallow[nr_shallow++] = info->ours[i];
 644         for (i = 0; i < info->nr_theirs; i++)
 645                 shallow[nr_shallow++] = info->theirs[i];
 646
 647         /*
 648          * Prepare the commit graph to track what refs can reach what
 649          * (new) shallow commits.
 650          */
 651         nr = get_max_object_index();
 652         for (i = 0; i < nr; i++) {
 653                 struct object *o = get_indexed_object(i);
 654                 if (!o || o->type != OBJ_COMMIT)
 655                         continue;
 656
 657                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
 658         }
 659
 660         memset(&pi, 0, sizeof(pi));
 661         init_ref_bitmap(&pi.ref_bitmap);
 662         pi.nr_bits = ref->nr;
 663
 664         /*
 665          * "--not --all" to cut short the traversal if new refs
 666          * connect to old refs. If not (e.g. force ref updates) it'll
 667          * have to go down to the current shallow commits.
 668          */
 669         head_ref(mark_uninteresting, NULL);
 670         for_each_ref(mark_uninteresting, NULL);
 671
 672         /* Mark potential bottoms so we won't go out of bound */
 673         for (i = 0; i < nr_shallow; i++) {
 674                 struct commit *c = lookup_commit(the_repository,
 675                                                  &oid[shallow[i]]);
 676                 c->object.flags |= BOTTOM;
 677         }
 678
 679         for (i = 0; i < ref->nr; i++)
 680                 paint_down(&pi, ref->oid + i, i);
 681
 682         if (used) {
 683                 int bitmap_size = DIV_ROUND_UP(pi.nr_bits, 32) * sizeof(uint32_t);
 684                 memset(used, 0, sizeof(*used) * info->shallow->nr);
 685                 for (i = 0; i < nr_shallow; i++) {
 686                         const struct commit *c = lookup_commit(the_repository,
 687                                                                &oid[shallow[i]]);
 688                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 689                         if (*map)
 690                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
 691                 }
 692                 /*
 693                  * unreachable shallow commits are not removed from
 694                  * "ours" and "theirs". The user is supposed to run
 695                  * step 7 on every ref separately and not trust "ours"
 696                  * and "theirs" any more.
 697                  */
 698         } else
 699                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
 700
 701         clear_ref_bitmap(&pi.ref_bitmap);
 702         for (i = 0; i < pi.pool_count; i++)
 703                 free(pi.pools[i]);
 704         free(pi.pools);
 705         free(shallow);
 706 }
 707
 708 struct commit_array {
 709         struct commit **commits;
 710         int nr, alloc;
 711 };
 712
 713 static int add_ref(const char *refname, const struct object_id *oid,
 714                    int flags, void *cb_data)
 715 {
 716         struct commit_array *ca = cb_data;
 717         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
 718         ca->commits[ca->nr] = lookup_commit_reference_gently(the_repository,
 719                                                              oid, 1);
 720         if (ca->commits[ca->nr])
 721                 ca->nr++;
 722         return 0;
 723 }
 724
 725 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
 726 {
 727         unsigned int i;
 728         if (!ref_status)
 729                 return;
 730         for (i = 0; i < nr; i++)
 731                 if (bitmap[i / 32] & (1U << (i % 32)))
 732                         ref_status[i]++;
 733 }
 734
 735 /*
 736  * Step 7, reachability test on "ours" at commit level
 737  */
 738 static void post_assign_shallow(struct shallow_info *info,
 739                                 struct ref_bitmap *ref_bitmap,
 740                                 int *ref_status)
 741 {
 742         struct object_id *oid = info->shallow->oid;
 743         struct commit *c;
 744         uint32_t **bitmap;
 745         int dst, i, j;
 746         int bitmap_nr = DIV_ROUND_UP(info->ref->nr, 32);
 747         struct commit_array ca;
 748
 749         trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
 750         if (ref_status)
 751                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
 752
 753         /* Remove unreachable shallow commits from "theirs" */
 754         for (i = dst = 0; i < info->nr_theirs; i++) {
 755                 if (i != dst)
 756                         info->theirs[dst] = info->theirs[i];
 757                 c = lookup_commit(the_repository, &oid[info->theirs[i]]);
 758                 bitmap = ref_bitmap_at(ref_bitmap, c);
 759                 if (!*bitmap)
 760                         continue;
 761                 for (j = 0; j < bitmap_nr; j++)
 762                         if (bitmap[0][j]) {
 763                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 764                                 dst++;
 765                                 break;
 766                         }
 767         }
 768         info->nr_theirs = dst;
 769
 770         memset(&ca, 0, sizeof(ca));
 771         head_ref(add_ref, &ca);
 772         for_each_ref(add_ref, &ca);
 773
 774         /* Remove unreachable shallow commits from "ours" */
 775         for (i = dst = 0; i < info->nr_ours; i++) {
 776                 if (i != dst)
 777                         info->ours[dst] = info->ours[i];
 778                 c = lookup_commit(the_repository, &oid[info->ours[i]]);
 779                 bitmap = ref_bitmap_at(ref_bitmap, c);
 780                 if (!*bitmap)
 781                         continue;
 782                 for (j = 0; j < bitmap_nr; j++)
 783                         if (bitmap[0][j] &&
 784                             /* Step 7, reachability test at commit level */
 785                             !in_merge_bases_many(c, ca.nr, ca.commits)) {
 786                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 787                                 dst++;
 788                                 break;
 789                         }
 790         }
 791         info->nr_ours = dst;
 792
 793         free(ca.commits);
 794 }
 795
 796 /* (Delayed) step 7, reachability test at commit level */
 797 int delayed_reachability_test(struct shallow_info *si, int c)
 798 {
 799         if (si->need_reachability_test[c]) {
 800                 struct commit *commit = lookup_commit(the_repository,
 801                                                       &si->shallow->oid[c]);
 802
 803                 if (!si->commits) {
 804                         struct commit_array ca;
 805
 806                         memset(&ca, 0, sizeof(ca));
 807                         head_ref(add_ref, &ca);
 808                         for_each_ref(add_ref, &ca);
 809                         si->commits = ca.commits;
 810                         si->nr_commits = ca.nr;
 811                 }
 812
 813                 si->reachable[c] = in_merge_bases_many(commit,
 814                                                        si->nr_commits,
 815                                                        si->commits);
 816                 si->need_reachability_test[c] = 0;
 817         }
 818         return si->reachable[c];
 819 }