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