shallow.c

   1 #include "git-compat-util.h"
   2 #include "hex.h"
   3 #include "repository.h"
   4 #include "tempfile.h"
   5 #include "lockfile.h"
   6 #include "object-store-ll.h"
   7 #include "commit.h"
   8 #include "tag.h"
   9 #include "pkt-line.h"
  10 #include "remote.h"
  11 #include "refs.h"
  12 #include "oid-array.h"
  13 #include "path.h"
  14 #include "diff.h"
  15 #include "revision.h"
  16 #include "commit-slab.h"
  17 #include "list-objects.h"
  18 #include "commit-reach.h"
  19 #include "shallow.h"
  20 #include "statinfo.h"
  21 #include "trace.h"
  22
  23 void set_alternate_shallow_file(struct repository *r, const char *path, int override)
  24 {
  25         if (r->parsed_objects->is_shallow != -1)
  26                 BUG("is_repository_shallow must not be called before set_alternate_shallow_file");
  27         if (r->parsed_objects->alternate_shallow_file && !override)
  28                 return;
  29         free(r->parsed_objects->alternate_shallow_file);
  30         r->parsed_objects->alternate_shallow_file = xstrdup_or_null(path);
  31 }
  32
  33 int register_shallow(struct repository *r, const struct object_id *oid)
  34 {
  35         struct commit_graft *graft =
  36                 xmalloc(sizeof(struct commit_graft));
  37         struct commit *commit = lookup_commit(r, oid);
  38
  39         oidcpy(&graft->oid, oid);
  40         graft->nr_parent = -1;
  41         if (commit && commit->object.parsed)
  42                 commit->parents = NULL;
  43         return register_commit_graft(r, graft, 0);
  44 }
  45
  46 int unregister_shallow(const struct object_id *oid)
  47 {
  48         int pos = commit_graft_pos(the_repository, oid);
  49         if (pos < 0)
  50                 return -1;
  51         if (pos + 1 < the_repository->parsed_objects->grafts_nr)
  52                 MOVE_ARRAY(the_repository->parsed_objects->grafts + pos,
  53                            the_repository->parsed_objects->grafts + pos + 1,
  54                            the_repository->parsed_objects->grafts_nr - pos - 1);
  55         the_repository->parsed_objects->grafts_nr--;
  56         return 0;
  57 }
  58
  59 int is_repository_shallow(struct repository *r)
  60 {
  61         FILE *fp;
  62         char buf[1024];
  63         const char *path = r->parsed_objects->alternate_shallow_file;
  64
  65         if (r->parsed_objects->is_shallow >= 0)
  66                 return r->parsed_objects->is_shallow;
  67
  68         if (!path)
  69                 path = git_path_shallow(r);
  70         /*
  71          * fetch-pack sets '--shallow-file ""' as an indicator that no
  72          * shallow file should be used. We could just open it and it
  73          * will likely fail. But let's do an explicit check instead.
  74          */
  75         if (!*path || (fp = fopen(path, "r")) == NULL) {
  76                 stat_validity_clear(r->parsed_objects->shallow_stat);
  77                 r->parsed_objects->is_shallow = 0;
  78                 return r->parsed_objects->is_shallow;
  79         }
  80         stat_validity_update(r->parsed_objects->shallow_stat, fileno(fp));
  81         r->parsed_objects->is_shallow = 1;
  82
  83         while (fgets(buf, sizeof(buf), fp)) {
  84                 struct object_id oid;
  85                 if (get_oid_hex(buf, &oid))
  86                         die("bad shallow line: %s", buf);
  87                 register_shallow(r, &oid);
  88         }
  89         fclose(fp);
  90         return r->parsed_objects->is_shallow;
  91 }
  92
  93 static void reset_repository_shallow(struct repository *r)
  94 {
  95         r->parsed_objects->is_shallow = -1;
  96         stat_validity_clear(r->parsed_objects->shallow_stat);
  97         reset_commit_grafts(r);
  98 }
  99
 100 int commit_shallow_file(struct repository *r, struct shallow_lock *lk)
 101 {
 102         int res = commit_lock_file(&lk->lock);
 103         reset_repository_shallow(r);
 104
 105         /*
 106          * Update in-memory data structures with the new shallow information,
 107          * including unparsing all commits that now have grafts.
 108          */
 109         is_repository_shallow(r);
 110
 111         return res;
 112 }
 113
 114 void rollback_shallow_file(struct repository *r, struct shallow_lock *lk)
 115 {
 116         rollback_lock_file(&lk->lock);
 117         reset_repository_shallow(r);
 118 }
 119
 120 /*
 121  * TODO: use "int" elemtype instead of "int *" when/if commit-slab
 122  * supports a "valid" flag.
 123  */
 124 define_commit_slab(commit_depth, int *);
 125 static void free_depth_in_slab(int **ptr)
 126 {
 127         FREE_AND_NULL(*ptr);
 128 }
 129 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
 130                 int shallow_flag, int not_shallow_flag)
 131 {
 132         int i = 0, cur_depth = 0;
 133         struct commit_list *result = NULL;
 134         struct object_array stack = OBJECT_ARRAY_INIT;
 135         struct commit *commit = NULL;
 136         struct commit_graft *graft;
 137         struct commit_depth depths;
 138
 139         init_commit_depth(&depths);
 140         while (commit || i < heads->nr || stack.nr) {
 141                 struct commit_list *p;
 142                 if (!commit) {
 143                         if (i < heads->nr) {
 144                                 int **depth_slot;
 145                                 commit = (struct commit *)
 146                                         deref_tag(the_repository,
 147                                                   heads->objects[i++].item,
 148                                                   NULL, 0);
 149                                 if (!commit || commit->object.type != OBJ_COMMIT) {
 150                                         commit = NULL;
 151                                         continue;
 152                                 }
 153                                 depth_slot = commit_depth_at(&depths, commit);
 154                                 if (!*depth_slot)
 155                                         *depth_slot = xmalloc(sizeof(int));
 156                                 **depth_slot = 0;
 157                                 cur_depth = 0;
 158                         } else {
 159                                 commit = (struct commit *)
 160                                         object_array_pop(&stack);
 161                                 cur_depth = **commit_depth_at(&depths, commit);
 162                         }
 163                 }
 164                 parse_commit_or_die(commit);
 165                 cur_depth++;
 166                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
 167                     (is_repository_shallow(the_repository) && !commit->parents &&
 168                      (graft = lookup_commit_graft(the_repository, &commit->object.oid)) != NULL &&
 169                      graft->nr_parent < 0)) {
 170                         commit_list_insert(commit, &result);
 171                         commit->object.flags |= shallow_flag;
 172                         commit = NULL;
 173                         continue;
 174                 }
 175                 commit->object.flags |= not_shallow_flag;
 176                 for (p = commit->parents, commit = NULL; p; p = p->next) {
 177                         int **depth_slot = commit_depth_at(&depths, p->item);
 178                         if (!*depth_slot) {
 179                                 *depth_slot = xmalloc(sizeof(int));
 180                                 **depth_slot = cur_depth;
 181                         } else {
 182                                 if (cur_depth >= **depth_slot)
 183                                         continue;
 184                                 **depth_slot = cur_depth;
 185                         }
 186                         if (p->next)
 187                                 add_object_array(&p->item->object,
 188                                                 NULL, &stack);
 189                         else {
 190                                 commit = p->item;
 191                                 cur_depth = **commit_depth_at(&depths, commit);
 192                         }
 193                 }
 194         }
 195         deep_clear_commit_depth(&depths, free_depth_in_slab);
 196
 197         return result;
 198 }
 199
 200 static void show_commit(struct commit *commit, void *data)
 201 {
 202         commit_list_insert(commit, data);
 203 }
 204
 205 /*
 206  * Given rev-list arguments, run rev-list. All reachable commits
 207  * except border ones are marked with not_shallow_flag. Border commits
 208  * are marked with shallow_flag. The list of border/shallow commits
 209  * are also returned.
 210  */
 211 struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av,
 212                                                     int shallow_flag,
 213                                                     int not_shallow_flag)
 214 {
 215         struct commit_list *result = NULL, *p;
 216         struct commit_list *not_shallow_list = NULL;
 217         struct rev_info revs;
 218         int both_flags = shallow_flag | not_shallow_flag;
 219
 220         /*
 221          * SHALLOW (excluded) and NOT_SHALLOW (included) should not be
 222          * set at this point. But better be safe than sorry.
 223          */
 224         clear_object_flags(both_flags);
 225
 226         is_repository_shallow(the_repository); /* make sure shallows are read */
 227
 228         repo_init_revisions(the_repository, &revs, NULL);
 229         save_commit_buffer = 0;
 230         setup_revisions(ac, av, &revs, NULL);
 231
 232         if (prepare_revision_walk(&revs))
 233                 die("revision walk setup failed");
 234         traverse_commit_list(&revs, show_commit, NULL, &not_shallow_list);
 235
 236         if (!not_shallow_list)
 237                 die("no commits selected for shallow requests");
 238
 239         /* Mark all reachable commits as NOT_SHALLOW */
 240         for (p = not_shallow_list; p; p = p->next)
 241                 p->item->object.flags |= not_shallow_flag;
 242
 243         /*
 244          * mark border commits SHALLOW + NOT_SHALLOW.
 245          * We cannot clear NOT_SHALLOW right now. Imagine border
 246          * commit A is processed first, then commit B, whose parent is
 247          * A, later. If NOT_SHALLOW on A is cleared at step 1, B
 248          * itself is considered border at step 2, which is incorrect.
 249          */
 250         for (p = not_shallow_list; p; p = p->next) {
 251                 struct commit *c = p->item;
 252                 struct commit_list *parent;
 253
 254                 if (repo_parse_commit(the_repository, c))
 255                         die("unable to parse commit %s",
 256                             oid_to_hex(&c->object.oid));
 257
 258                 for (parent = c->parents; parent; parent = parent->next)
 259                         if (!(parent->item->object.flags & not_shallow_flag)) {
 260                                 c->object.flags |= shallow_flag;
 261                                 commit_list_insert(c, &result);
 262                                 break;
 263                         }
 264         }
 265         free_commit_list(not_shallow_list);
 266
 267         /*
 268          * Now we can clean up NOT_SHALLOW on border commits. Having
 269          * both flags set can confuse the caller.
 270          */
 271         for (p = result; p; p = p->next) {
 272                 struct object *o = &p->item->object;
 273                 if ((o->flags & both_flags) == both_flags)
 274                         o->flags &= ~not_shallow_flag;
 275         }
 276         release_revisions(&revs);
 277         return result;
 278 }
 279
 280 static void check_shallow_file_for_update(struct repository *r)
 281 {
 282         if (r->parsed_objects->is_shallow == -1)
 283                 BUG("shallow must be initialized by now");
 284
 285         if (!stat_validity_check(r->parsed_objects->shallow_stat,
 286                                  git_path_shallow(r)))
 287                 die("shallow file has changed since we read it");
 288 }
 289
 290 #define SEEN_ONLY 1
 291 #define VERBOSE   2
 292 #define QUICK 4
 293
 294 struct write_shallow_data {
 295         struct strbuf *out;
 296         int use_pack_protocol;
 297         int count;
 298         unsigned flags;
 299 };
 300
 301 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 302 {
 303         struct write_shallow_data *data = cb_data;
 304         const char *hex = oid_to_hex(&graft->oid);
 305         if (graft->nr_parent != -1)
 306                 return 0;
 307         if (data->flags & QUICK) {
 308                 if (!repo_has_object_file(the_repository, &graft->oid))
 309                         return 0;
 310         } else if (data->flags & SEEN_ONLY) {
 311                 struct commit *c = lookup_commit(the_repository, &graft->oid);
 312                 if (!c || !(c->object.flags & SEEN)) {
 313                         if (data->flags & VERBOSE)
 314                                 printf("Removing %s from .git/shallow\n",
 315                                        oid_to_hex(&c->object.oid));
 316                         return 0;
 317                 }
 318         }
 319         data->count++;
 320         if (data->use_pack_protocol)
 321                 packet_buf_write(data->out, "shallow %s", hex);
 322         else {
 323                 strbuf_addstr(data->out, hex);
 324                 strbuf_addch(data->out, '\n');
 325         }
 326         return 0;
 327 }
 328
 329 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
 330                                    const struct oid_array *extra,
 331                                    unsigned flags)
 332 {
 333         struct write_shallow_data data;
 334         int i;
 335         data.out = out;
 336         data.use_pack_protocol = use_pack_protocol;
 337         data.count = 0;
 338         data.flags = flags;
 339         for_each_commit_graft(write_one_shallow, &data);
 340         if (!extra)
 341                 return data.count;
 342         for (i = 0; i < extra->nr; i++) {
 343                 strbuf_addstr(out, oid_to_hex(extra->oid + i));
 344                 strbuf_addch(out, '\n');
 345                 data.count++;
 346         }
 347         return data.count;
 348 }
 349
 350 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
 351                           const struct oid_array *extra)
 352 {
 353         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
 354 }
 355
 356 const char *setup_temporary_shallow(const struct oid_array *extra)
 357 {
 358         struct tempfile *temp;
 359         struct strbuf sb = STRBUF_INIT;
 360
 361         if (write_shallow_commits(&sb, 0, extra)) {
 362                 temp = xmks_tempfile(git_path("shallow_XXXXXX"));
 363
 364                 if (write_in_full(temp->fd, sb.buf, sb.len) < 0 ||
 365                     close_tempfile_gently(temp) < 0)
 366                         die_errno("failed to write to %s",
 367                                   get_tempfile_path(temp));
 368                 strbuf_release(&sb);
 369                 return get_tempfile_path(temp);
 370         }
 371         /*
 372          * is_repository_shallow() sees empty string as "no shallow
 373          * file".
 374          */
 375         return "";
 376 }
 377
 378 void setup_alternate_shallow(struct shallow_lock *shallow_lock,
 379                              const char **alternate_shallow_file,
 380                              const struct oid_array *extra)
 381 {
 382         struct strbuf sb = STRBUF_INIT;
 383         int fd;
 384
 385         fd = hold_lock_file_for_update(&shallow_lock->lock,
 386                                        git_path_shallow(the_repository),
 387                                        LOCK_DIE_ON_ERROR);
 388         check_shallow_file_for_update(the_repository);
 389         if (write_shallow_commits(&sb, 0, extra)) {
 390                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 391                         die_errno("failed to write to %s",
 392                                   get_lock_file_path(&shallow_lock->lock));
 393                 *alternate_shallow_file = get_lock_file_path(&shallow_lock->lock);
 394         } else
 395                 /*
 396                  * is_repository_shallow() sees empty string as "no
 397                  * shallow file".
 398                  */
 399                 *alternate_shallow_file = "";
 400         strbuf_release(&sb);
 401 }
 402
 403 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
 404 {
 405         int fd = *(int *)cb;
 406         if (graft->nr_parent == -1)
 407                 packet_write_fmt(fd, "shallow %s\n", oid_to_hex(&graft->oid));
 408         return 0;
 409 }
 410
 411 void advertise_shallow_grafts(int fd)
 412 {
 413         if (!is_repository_shallow(the_repository))
 414                 return;
 415         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
 416 }
 417
 418 /*
 419  * mark_reachable_objects() should have been run prior to this and all
 420  * reachable commits marked as "SEEN", except when quick_prune is non-zero,
 421  * in which case lines are excised from the shallow file if they refer to
 422  * commits that do not exist (any longer).
 423  */
 424 void prune_shallow(unsigned options)
 425 {
 426         struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
 427         struct strbuf sb = STRBUF_INIT;
 428         unsigned flags = SEEN_ONLY;
 429         int fd;
 430
 431         if (options & PRUNE_QUICK)
 432                 flags |= QUICK;
 433
 434         if (options & PRUNE_SHOW_ONLY) {
 435                 flags |= VERBOSE;
 436                 write_shallow_commits_1(&sb, 0, NULL, flags);
 437                 strbuf_release(&sb);
 438                 return;
 439         }
 440         fd = hold_lock_file_for_update(&shallow_lock.lock,
 441                                        git_path_shallow(the_repository),
 442                                        LOCK_DIE_ON_ERROR);
 443         check_shallow_file_for_update(the_repository);
 444         if (write_shallow_commits_1(&sb, 0, NULL, flags)) {
 445                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 446                         die_errno("failed to write to %s",
 447                                   get_lock_file_path(&shallow_lock.lock));
 448                 commit_shallow_file(the_repository, &shallow_lock);
 449         } else {
 450                 unlink(git_path_shallow(the_repository));
 451                 rollback_shallow_file(the_repository, &shallow_lock);
 452         }
 453         strbuf_release(&sb);
 454 }
 455
 456 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
 457
 458 /*
 459  * Step 1, split sender shallow commits into "ours" and "theirs"
 460  * Step 2, clean "ours" based on .git/shallow
 461  */
 462 void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa)
 463 {
 464         int i;
 465         trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
 466         memset(info, 0, sizeof(*info));
 467         info->shallow = sa;
 468         if (!sa)
 469                 return;
 470         ALLOC_ARRAY(info->ours, sa->nr);
 471         ALLOC_ARRAY(info->theirs, sa->nr);
 472         for (i = 0; i < sa->nr; i++) {
 473                 if (repo_has_object_file(the_repository, sa->oid + i)) {
 474                         struct commit_graft *graft;
 475                         graft = lookup_commit_graft(the_repository,
 476                                                     &sa->oid[i]);
 477                         if (graft && graft->nr_parent < 0)
 478                                 continue;
 479                         info->ours[info->nr_ours++] = i;
 480                 } else
 481                         info->theirs[info->nr_theirs++] = i;
 482         }
 483 }
 484
 485 void clear_shallow_info(struct shallow_info *info)
 486 {
 487         free(info->ours);
 488         free(info->theirs);
 489 }
 490
 491 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
 492
 493 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 494 {
 495         struct object_id *oid = info->shallow->oid;
 496         int i, dst;
 497         trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
 498         for (i = dst = 0; i < info->nr_theirs; i++) {
 499                 if (i != dst)
 500                         info->theirs[dst] = info->theirs[i];
 501                 if (repo_has_object_file(the_repository, oid + info->theirs[i]))
 502                         dst++;
 503         }
 504         info->nr_theirs = dst;
 505 }
 506
 507 define_commit_slab(ref_bitmap, uint32_t *);
 508
 509 #define POOL_SIZE (512 * 1024)
 510
 511 struct paint_info {
 512         struct ref_bitmap ref_bitmap;
 513         unsigned nr_bits;
 514         char **pools;
 515         char *free, *end;
 516         unsigned pool_count;
 517 };
 518
 519 static uint32_t *paint_alloc(struct paint_info *info)
 520 {
 521         unsigned nr = DIV_ROUND_UP(info->nr_bits, 32);
 522         unsigned size = nr * sizeof(uint32_t);
 523         void *p;
 524         if (!info->pool_count || size > info->end - info->free) {
 525                 if (size > POOL_SIZE)
 526                         BUG("pool size too small for %d in paint_alloc()",
 527                             size);
 528                 info->pool_count++;
 529                 REALLOC_ARRAY(info->pools, info->pool_count);
 530                 info->free = xmalloc(POOL_SIZE);
 531                 info->pools[info->pool_count - 1] = info->free;
 532                 info->end = info->free + POOL_SIZE;
 533         }
 534         p = info->free;
 535         info->free += size;
 536         return p;
 537 }
 538
 539 /*
 540  * Given a commit SHA-1, walk down to parents until either SEEN,
 541  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
 542  * all walked commits.
 543  */
 544 static void paint_down(struct paint_info *info, const struct object_id *oid,
 545                        unsigned int id)
 546 {
 547         unsigned int i, nr;
 548         struct commit_list *head = NULL;
 549         int bitmap_nr = DIV_ROUND_UP(info->nr_bits, 32);
 550         size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
 551         struct commit *c = lookup_commit_reference_gently(the_repository, oid,
 552                                                           1);
 553         uint32_t *tmp; /* to be freed before return */
 554         uint32_t *bitmap;
 555
 556         if (!c)
 557                 return;
 558
 559         tmp = xmalloc(bitmap_size);
 560         bitmap = paint_alloc(info);
 561         memset(bitmap, 0, bitmap_size);
 562         bitmap[id / 32] |= (1U << (id % 32));
 563         commit_list_insert(c, &head);
 564         while (head) {
 565                 struct commit_list *p;
 566                 struct commit *c = pop_commit(&head);
 567                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 568
 569                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
 570                 if (c->object.flags & (SEEN | UNINTERESTING))
 571                         continue;
 572                 else
 573                         c->object.flags |= SEEN;
 574
 575                 if (!*refs)
 576                         *refs = bitmap;
 577                 else {
 578                         memcpy(tmp, *refs, bitmap_size);
 579                         for (i = 0; i < bitmap_nr; i++)
 580                                 tmp[i] |= bitmap[i];
 581                         if (memcmp(tmp, *refs, bitmap_size)) {
 582                                 *refs = paint_alloc(info);
 583                                 memcpy(*refs, tmp, bitmap_size);
 584                         }
 585                 }
 586
 587                 if (c->object.flags & BOTTOM)
 588                         continue;
 589
 590                 if (repo_parse_commit(the_repository, c))
 591                         die("unable to parse commit %s",
 592                             oid_to_hex(&c->object.oid));
 593
 594                 for (p = c->parents; p; p = p->next) {
 595                         if (p->item->object.flags & SEEN)
 596                                 continue;
 597                         commit_list_insert(p->item, &head);
 598                 }
 599         }
 600
 601         nr = get_max_object_index();
 602         for (i = 0; i < nr; i++) {
 603                 struct object *o = get_indexed_object(i);
 604                 if (o && o->type == OBJ_COMMIT)
 605                         o->flags &= ~SEEN;
 606         }
 607
 608         free(tmp);
 609 }
 610
 611 static int mark_uninteresting(const char *refname UNUSED,
 612                               const struct object_id *oid,
 613                               int flags UNUSED,
 614                               void *cb_data UNUSED)
 615 {
 616         struct commit *commit = lookup_commit_reference_gently(the_repository,
 617                                                                oid, 1);
 618         if (!commit)
 619                 return 0;
 620         commit->object.flags |= UNINTERESTING;
 621         mark_parents_uninteresting(NULL, commit);
 622         return 0;
 623 }
 624
 625 static void post_assign_shallow(struct shallow_info *info,
 626                                 struct ref_bitmap *ref_bitmap,
 627                                 int *ref_status);
 628 /*
 629  * Step 6(+7), associate shallow commits with new refs
 630  *
 631  * info->ref must be initialized before calling this function.
 632  *
 633  * If used is not NULL, it's an array of info->shallow->nr
 634  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
 635  * m-th shallow commit from info->shallow.
 636  *
 637  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
 638  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
 639  * the ref needs some shallow commits from either info->ours or
 640  * info->theirs.
 641  */
 642 void assign_shallow_commits_to_refs(struct shallow_info *info,
 643                                     uint32_t **used, int *ref_status)
 644 {
 645         struct object_id *oid = info->shallow->oid;
 646         struct oid_array *ref = info->ref;
 647         unsigned int i, nr;
 648         int *shallow, nr_shallow = 0;
 649         struct paint_info pi;
 650
 651         trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
 652         ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs);
 653         for (i = 0; i < info->nr_ours; i++)
 654                 shallow[nr_shallow++] = info->ours[i];
 655         for (i = 0; i < info->nr_theirs; i++)
 656                 shallow[nr_shallow++] = info->theirs[i];
 657
 658         /*
 659          * Prepare the commit graph to track what refs can reach what
 660          * (new) shallow commits.
 661          */
 662         nr = get_max_object_index();
 663         for (i = 0; i < nr; i++) {
 664                 struct object *o = get_indexed_object(i);
 665                 if (!o || o->type != OBJ_COMMIT)
 666                         continue;
 667
 668                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
 669         }
 670
 671         memset(&pi, 0, sizeof(pi));
 672         init_ref_bitmap(&pi.ref_bitmap);
 673         pi.nr_bits = ref->nr;
 674
 675         /*
 676          * "--not --all" to cut short the traversal if new refs
 677          * connect to old refs. If not (e.g. force ref updates) it'll
 678          * have to go down to the current shallow commits.
 679          */
 680         head_ref(mark_uninteresting, NULL);
 681         for_each_ref(mark_uninteresting, NULL);
 682
 683         /* Mark potential bottoms so we won't go out of bound */
 684         for (i = 0; i < nr_shallow; i++) {
 685                 struct commit *c = lookup_commit(the_repository,
 686                                                  &oid[shallow[i]]);
 687                 c->object.flags |= BOTTOM;
 688         }
 689
 690         for (i = 0; i < ref->nr; i++)
 691                 paint_down(&pi, ref->oid + i, i);
 692
 693         if (used) {
 694                 int bitmap_size = DIV_ROUND_UP(pi.nr_bits, 32) * sizeof(uint32_t);
 695                 memset(used, 0, sizeof(*used) * info->shallow->nr);
 696                 for (i = 0; i < nr_shallow; i++) {
 697                         const struct commit *c = lookup_commit(the_repository,
 698                                                                &oid[shallow[i]]);
 699                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 700                         if (*map)
 701                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
 702                 }
 703                 /*
 704                  * unreachable shallow commits are not removed from
 705                  * "ours" and "theirs". The user is supposed to run
 706                  * step 7 on every ref separately and not trust "ours"
 707                  * and "theirs" any more.
 708                  */
 709         } else
 710                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
 711
 712         clear_ref_bitmap(&pi.ref_bitmap);
 713         for (i = 0; i < pi.pool_count; i++)
 714                 free(pi.pools[i]);
 715         free(pi.pools);
 716         free(shallow);
 717 }
 718
 719 struct commit_array {
 720         struct commit **commits;
 721         int nr, alloc;
 722 };
 723
 724 static int add_ref(const char *refname UNUSED,
 725                    const struct object_id *oid,
 726                    int flags UNUSED,
 727                    void *cb_data)
 728 {
 729         struct commit_array *ca = cb_data;
 730         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
 731         ca->commits[ca->nr] = lookup_commit_reference_gently(the_repository,
 732                                                              oid, 1);
 733         if (ca->commits[ca->nr])
 734                 ca->nr++;
 735         return 0;
 736 }
 737
 738 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
 739 {
 740         unsigned int i;
 741         if (!ref_status)
 742                 return;
 743         for (i = 0; i < nr; i++)
 744                 if (bitmap[i / 32] & (1U << (i % 32)))
 745                         ref_status[i]++;
 746 }
 747
 748 /*
 749  * Step 7, reachability test on "ours" at commit level
 750  */
 751 static void post_assign_shallow(struct shallow_info *info,
 752                                 struct ref_bitmap *ref_bitmap,
 753                                 int *ref_status)
 754 {
 755         struct object_id *oid = info->shallow->oid;
 756         struct commit *c;
 757         uint32_t **bitmap;
 758         int dst, i, j;
 759         int bitmap_nr = DIV_ROUND_UP(info->ref->nr, 32);
 760         struct commit_array ca;
 761
 762         trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
 763         if (ref_status)
 764                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
 765
 766         /* Remove unreachable shallow commits from "theirs" */
 767         for (i = dst = 0; i < info->nr_theirs; i++) {
 768                 if (i != dst)
 769                         info->theirs[dst] = info->theirs[i];
 770                 c = lookup_commit(the_repository, &oid[info->theirs[i]]);
 771                 bitmap = ref_bitmap_at(ref_bitmap, c);
 772                 if (!*bitmap)
 773                         continue;
 774                 for (j = 0; j < bitmap_nr; j++)
 775                         if (bitmap[0][j]) {
 776                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 777                                 dst++;
 778                                 break;
 779                         }
 780         }
 781         info->nr_theirs = dst;
 782
 783         memset(&ca, 0, sizeof(ca));
 784         head_ref(add_ref, &ca);
 785         for_each_ref(add_ref, &ca);
 786
 787         /* Remove unreachable shallow commits from "ours" */
 788         for (i = dst = 0; i < info->nr_ours; i++) {
 789                 if (i != dst)
 790                         info->ours[dst] = info->ours[i];
 791                 c = lookup_commit(the_repository, &oid[info->ours[i]]);
 792                 bitmap = ref_bitmap_at(ref_bitmap, c);
 793                 if (!*bitmap)
 794                         continue;
 795                 for (j = 0; j < bitmap_nr; j++)
 796                         if (bitmap[0][j] &&
 797                             /* Step 7, reachability test at commit level */
 798                             !repo_in_merge_bases_many(the_repository, c, ca.nr, ca.commits)) {
 799                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 800                                 dst++;
 801                                 break;
 802                         }
 803         }
 804         info->nr_ours = dst;
 805
 806         free(ca.commits);
 807 }
 808
 809 /* (Delayed) step 7, reachability test at commit level */
 810 int delayed_reachability_test(struct shallow_info *si, int c)
 811 {
 812         if (si->need_reachability_test[c]) {
 813                 struct commit *commit = lookup_commit(the_repository,
 814                                                       &si->shallow->oid[c]);
 815
 816                 if (!si->commits) {
 817                         struct commit_array ca;
 818
 819                         memset(&ca, 0, sizeof(ca));
 820                         head_ref(add_ref, &ca);
 821                         for_each_ref(add_ref, &ca);
 822                         si->commits = ca.commits;
 823                         si->nr_commits = ca.nr;
 824                 }
 825
 826                 si->reachable[c] = repo_in_merge_bases_many(the_repository,
 827                                                             commit,
 828                                                             si->nr_commits,
 829                                                             si->commits);
 830                 si->need_reachability_test[c] = 0;
 831         }
 832         return si->reachable[c];
 833 }