shallow.c

   1 #define USE_THE_REPOSITORY_VARIABLE
   2
   3 #include "git-compat-util.h"
   4 #include "hex.h"
   5 #include "repository.h"
   6 #include "tempfile.h"
   7 #include "lockfile.h"
   8 #include "odb.h"
   9 #include "commit.h"
  10 #include "tag.h"
  11 #include "pkt-line.h"
  12 #include "refs.h"
  13 #include "oid-array.h"
  14 #include "path.h"
  15 #include "diff.h"
  16 #include "revision.h"
  17 #include "commit-slab.h"
  18 #include "list-objects.h"
  19 #include "commit-reach.h"
  20 #include "shallow.h"
  21 #include "statinfo.h"
  22 #include "trace.h"
  23
  24 void set_alternate_shallow_file(struct repository *r, const char *path, int override)
  25 {
  26         if (r->parsed_objects->is_shallow != -1)
  27                 BUG("is_repository_shallow must not be called before set_alternate_shallow_file");
  28         if (r->parsed_objects->alternate_shallow_file && !override)
  29                 return;
  30         free(r->parsed_objects->alternate_shallow_file);
  31         r->parsed_objects->alternate_shallow_file = xstrdup_or_null(path);
  32 }
  33
  34 int register_shallow(struct repository *r, const struct object_id *oid)
  35 {
  36         struct commit_graft *graft =
  37                 xmalloc(sizeof(struct commit_graft));
  38         struct commit *commit = lookup_commit(r, oid);
  39
  40         oidcpy(&graft->oid, oid);
  41         graft->nr_parent = -1;
  42         if (commit && commit->object.parsed) {
  43                 free_commit_list(commit->parents);
  44                 commit->parents = NULL;
  45         }
  46         return register_commit_graft(r, graft, 0);
  47 }
  48
  49 int unregister_shallow(const struct object_id *oid)
  50 {
  51         int pos = commit_graft_pos(the_repository, oid);
  52         if (pos < 0)
  53                 return -1;
  54         free(the_repository->parsed_objects->grafts[pos]);
  55         if (pos + 1 < the_repository->parsed_objects->grafts_nr)
  56                 MOVE_ARRAY(the_repository->parsed_objects->grafts + pos,
  57                            the_repository->parsed_objects->grafts + pos + 1,
  58                            the_repository->parsed_objects->grafts_nr - pos - 1);
  59         the_repository->parsed_objects->grafts_nr--;
  60         return 0;
  61 }
  62
  63 int is_repository_shallow(struct repository *r)
  64 {
  65         FILE *fp;
  66         char buf[1024];
  67         const char *path = r->parsed_objects->alternate_shallow_file;
  68
  69         if (r->parsed_objects->is_shallow >= 0)
  70                 return r->parsed_objects->is_shallow;
  71
  72         if (!path)
  73                 path = git_path_shallow(r);
  74         /*
  75          * fetch-pack sets '--shallow-file ""' as an indicator that no
  76          * shallow file should be used. We could just open it and it
  77          * will likely fail. But let's do an explicit check instead.
  78          */
  79         if (!*path || (fp = fopen(path, "r")) == NULL) {
  80                 stat_validity_clear(r->parsed_objects->shallow_stat);
  81                 r->parsed_objects->is_shallow = 0;
  82                 return r->parsed_objects->is_shallow;
  83         }
  84         stat_validity_update(r->parsed_objects->shallow_stat, fileno(fp));
  85         r->parsed_objects->is_shallow = 1;
  86
  87         while (fgets(buf, sizeof(buf), fp)) {
  88                 struct object_id oid;
  89                 if (get_oid_hex(buf, &oid))
  90                         die("bad shallow line: %s", buf);
  91                 register_shallow(r, &oid);
  92         }
  93         fclose(fp);
  94         return r->parsed_objects->is_shallow;
  95 }
  96
  97 static void reset_repository_shallow(struct repository *r)
  98 {
  99         r->parsed_objects->is_shallow = -1;
 100         stat_validity_clear(r->parsed_objects->shallow_stat);
 101         parsed_object_pool_reset_commit_grafts(r->parsed_objects);
 102 }
 103
 104 int commit_shallow_file(struct repository *r, struct shallow_lock *lk)
 105 {
 106         int res = commit_lock_file(&lk->lock);
 107         reset_repository_shallow(r);
 108
 109         /*
 110          * Update in-memory data structures with the new shallow information,
 111          * including unparsing all commits that now have grafts.
 112          */
 113         is_repository_shallow(r);
 114
 115         return res;
 116 }
 117
 118 void rollback_shallow_file(struct repository *r, struct shallow_lock *lk)
 119 {
 120         rollback_lock_file(&lk->lock);
 121         reset_repository_shallow(r);
 122 }
 123
 124 /*
 125  * TODO: use "int" elemtype instead of "int *" when/if commit-slab
 126  * supports a "valid" flag.
 127  */
 128 define_commit_slab(commit_depth, int *);
 129 static void free_depth_in_slab(int **ptr)
 130 {
 131         FREE_AND_NULL(*ptr);
 132 }
 133 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
 134                 int shallow_flag, int not_shallow_flag)
 135 {
 136         size_t i = 0;
 137         int cur_depth = 0;
 138         struct commit_list *result = NULL;
 139         struct object_array stack = OBJECT_ARRAY_INIT;
 140         struct commit *commit = NULL;
 141         struct commit_graft *graft;
 142         struct commit_depth depths;
 143
 144         init_commit_depth(&depths);
 145         while (commit || i < heads->nr || stack.nr) {
 146                 struct commit_list *p;
 147                 if (!commit) {
 148                         if (i < heads->nr) {
 149                                 int **depth_slot;
 150                                 commit = (struct commit *)
 151                                         deref_tag(the_repository,
 152                                                   heads->objects[i++].item,
 153                                                   NULL, 0);
 154                                 if (!commit || commit->object.type != OBJ_COMMIT) {
 155                                         commit = NULL;
 156                                         continue;
 157                                 }
 158                                 depth_slot = commit_depth_at(&depths, commit);
 159                                 if (!*depth_slot)
 160                                         *depth_slot = xmalloc(sizeof(int));
 161                                 **depth_slot = 0;
 162                                 cur_depth = 0;
 163                         } else {
 164                                 commit = (struct commit *)
 165                                         object_array_pop(&stack);
 166                                 cur_depth = **commit_depth_at(&depths, commit);
 167                         }
 168                 }
 169                 parse_commit_or_die(commit);
 170                 cur_depth++;
 171                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
 172                     (is_repository_shallow(the_repository) && !commit->parents &&
 173                      (graft = lookup_commit_graft(the_repository, &commit->object.oid)) != NULL &&
 174                      graft->nr_parent < 0)) {
 175                         commit_list_insert(commit, &result);
 176                         commit->object.flags |= shallow_flag;
 177                         commit = NULL;
 178                         continue;
 179                 }
 180                 commit->object.flags |= not_shallow_flag;
 181                 for (p = commit->parents, commit = NULL; p; p = p->next) {
 182                         int **depth_slot = commit_depth_at(&depths, p->item);
 183                         if (!*depth_slot) {
 184                                 *depth_slot = xmalloc(sizeof(int));
 185                                 **depth_slot = cur_depth;
 186                         } else {
 187                                 if (cur_depth >= **depth_slot)
 188                                         continue;
 189                                 **depth_slot = cur_depth;
 190                         }
 191                         if (p->next)
 192                                 add_object_array(&p->item->object,
 193                                                 NULL, &stack);
 194                         else {
 195                                 commit = p->item;
 196                                 cur_depth = **commit_depth_at(&depths, commit);
 197                         }
 198                 }
 199         }
 200         deep_clear_commit_depth(&depths, free_depth_in_slab);
 201
 202         return result;
 203 }
 204
 205 static void show_commit(struct commit *commit, void *data)
 206 {
 207         commit_list_insert(commit, data);
 208 }
 209
 210 /*
 211  * Given rev-list arguments, run rev-list. All reachable commits
 212  * except border ones are marked with not_shallow_flag. Border commits
 213  * are marked with shallow_flag. The list of border/shallow commits
 214  * are also returned.
 215  */
 216 struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av,
 217                                                     int shallow_flag,
 218                                                     int not_shallow_flag)
 219 {
 220         struct commit_list *result = NULL, *p;
 221         struct commit_list *not_shallow_list = NULL;
 222         struct rev_info revs;
 223         int both_flags = shallow_flag | not_shallow_flag;
 224
 225         /*
 226          * SHALLOW (excluded) and NOT_SHALLOW (included) should not be
 227          * set at this point. But better be safe than sorry.
 228          */
 229         clear_object_flags(the_repository, both_flags);
 230
 231         is_repository_shallow(the_repository); /* make sure shallows are read */
 232
 233         repo_init_revisions(the_repository, &revs, NULL);
 234         save_commit_buffer = 0;
 235         setup_revisions(ac, av, &revs, NULL);
 236
 237         if (prepare_revision_walk(&revs))
 238                 die("revision walk setup failed");
 239         traverse_commit_list(&revs, show_commit, NULL, &not_shallow_list);
 240
 241         if (!not_shallow_list)
 242                 die("no commits selected for shallow requests");
 243
 244         /* Mark all reachable commits as NOT_SHALLOW */
 245         for (p = not_shallow_list; p; p = p->next)
 246                 p->item->object.flags |= not_shallow_flag;
 247
 248         /*
 249          * mark border commits SHALLOW + NOT_SHALLOW.
 250          * We cannot clear NOT_SHALLOW right now. Imagine border
 251          * commit A is processed first, then commit B, whose parent is
 252          * A, later. If NOT_SHALLOW on A is cleared at step 1, B
 253          * itself is considered border at step 2, which is incorrect.
 254          */
 255         for (p = not_shallow_list; p; p = p->next) {
 256                 struct commit *c = p->item;
 257                 struct commit_list *parent;
 258
 259                 if (repo_parse_commit(the_repository, c))
 260                         die("unable to parse commit %s",
 261                             oid_to_hex(&c->object.oid));
 262
 263                 for (parent = c->parents; parent; parent = parent->next)
 264                         if (!(parent->item->object.flags & not_shallow_flag)) {
 265                                 c->object.flags |= shallow_flag;
 266                                 commit_list_insert(c, &result);
 267                                 break;
 268                         }
 269         }
 270         free_commit_list(not_shallow_list);
 271
 272         /*
 273          * Now we can clean up NOT_SHALLOW on border commits. Having
 274          * both flags set can confuse the caller.
 275          */
 276         for (p = result; p; p = p->next) {
 277                 struct object *o = &p->item->object;
 278                 if ((o->flags & both_flags) == both_flags)
 279                         o->flags &= ~not_shallow_flag;
 280         }
 281         release_revisions(&revs);
 282         return result;
 283 }
 284
 285 static void check_shallow_file_for_update(struct repository *r)
 286 {
 287         if (r->parsed_objects->is_shallow == -1)
 288                 BUG("shallow must be initialized by now");
 289
 290         if (!stat_validity_check(r->parsed_objects->shallow_stat,
 291                                  git_path_shallow(r)))
 292                 die("shallow file has changed since we read it");
 293 }
 294
 295 #define SEEN_ONLY 1
 296 #define VERBOSE   2
 297 #define QUICK 4
 298
 299 struct write_shallow_data {
 300         struct strbuf *out;
 301         int use_pack_protocol;
 302         int count;
 303         unsigned flags;
 304 };
 305
 306 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 307 {
 308         struct write_shallow_data *data = cb_data;
 309         const char *hex = oid_to_hex(&graft->oid);
 310         if (graft->nr_parent != -1)
 311                 return 0;
 312         if (data->flags & QUICK) {
 313                 if (!odb_has_object(the_repository->objects, &graft->oid,
 314                                     HAS_OBJECT_RECHECK_PACKED | HAS_OBJECT_FETCH_PROMISOR))
 315                         return 0;
 316         } else if (data->flags & SEEN_ONLY) {
 317                 struct commit *c = lookup_commit(the_repository, &graft->oid);
 318                 if (!c || !(c->object.flags & SEEN)) {
 319                         if (data->flags & VERBOSE)
 320                                 printf("Removing %s from .git/shallow\n",
 321                                        oid_to_hex(&c->object.oid));
 322                         return 0;
 323                 }
 324         }
 325         data->count++;
 326         if (data->use_pack_protocol)
 327                 packet_buf_write(data->out, "shallow %s", hex);
 328         else {
 329                 strbuf_addstr(data->out, hex);
 330                 strbuf_addch(data->out, '\n');
 331         }
 332         return 0;
 333 }
 334
 335 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
 336                                    const struct oid_array *extra,
 337                                    unsigned flags)
 338 {
 339         struct write_shallow_data data = {
 340                 .out = out,
 341                 .use_pack_protocol = use_pack_protocol,
 342                 .flags = flags,
 343         };
 344
 345         for_each_commit_graft(write_one_shallow, &data);
 346         if (!extra)
 347                 return data.count;
 348         for (size_t i = 0; i < extra->nr; i++) {
 349                 strbuf_addstr(out, oid_to_hex(extra->oid + i));
 350                 strbuf_addch(out, '\n');
 351                 data.count++;
 352         }
 353         return data.count;
 354 }
 355
 356 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
 357                           const struct oid_array *extra)
 358 {
 359         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
 360 }
 361
 362 const char *setup_temporary_shallow(const struct oid_array *extra)
 363 {
 364         struct tempfile *temp;
 365         struct strbuf sb = STRBUF_INIT;
 366
 367         if (write_shallow_commits(&sb, 0, extra)) {
 368                 char *path = repo_git_path(the_repository, "shallow_XXXXXX");
 369                 temp = xmks_tempfile(path);
 370                 free(path);
 371
 372                 if (write_in_full(temp->fd, sb.buf, sb.len) < 0 ||
 373                     close_tempfile_gently(temp) < 0)
 374                         die_errno("failed to write to %s",
 375                                   get_tempfile_path(temp));
 376                 strbuf_release(&sb);
 377                 return get_tempfile_path(temp);
 378         }
 379         /*
 380          * is_repository_shallow() sees empty string as "no shallow
 381          * file".
 382          */
 383         return "";
 384 }
 385
 386 void setup_alternate_shallow(struct shallow_lock *shallow_lock,
 387                              const char **alternate_shallow_file,
 388                              const struct oid_array *extra)
 389 {
 390         struct strbuf sb = STRBUF_INIT;
 391         int fd;
 392
 393         fd = hold_lock_file_for_update(&shallow_lock->lock,
 394                                        git_path_shallow(the_repository),
 395                                        LOCK_DIE_ON_ERROR);
 396         check_shallow_file_for_update(the_repository);
 397         if (write_shallow_commits(&sb, 0, extra)) {
 398                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 399                         die_errno("failed to write to %s",
 400                                   get_lock_file_path(&shallow_lock->lock));
 401                 *alternate_shallow_file = get_lock_file_path(&shallow_lock->lock);
 402         } else
 403                 /*
 404                  * is_repository_shallow() sees empty string as "no
 405                  * shallow file".
 406                  */
 407                 *alternate_shallow_file = "";
 408         strbuf_release(&sb);
 409 }
 410
 411 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
 412 {
 413         int fd = *(int *)cb;
 414         if (graft->nr_parent == -1)
 415                 packet_write_fmt(fd, "shallow %s\n", oid_to_hex(&graft->oid));
 416         return 0;
 417 }
 418
 419 void advertise_shallow_grafts(int fd)
 420 {
 421         if (!is_repository_shallow(the_repository))
 422                 return;
 423         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
 424 }
 425
 426 /*
 427  * mark_reachable_objects() should have been run prior to this and all
 428  * reachable commits marked as "SEEN", except when quick_prune is non-zero,
 429  * in which case lines are excised from the shallow file if they refer to
 430  * commits that do not exist (any longer).
 431  */
 432 void prune_shallow(unsigned options)
 433 {
 434         struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
 435         struct strbuf sb = STRBUF_INIT;
 436         unsigned flags = SEEN_ONLY;
 437         int fd;
 438
 439         if (options & PRUNE_QUICK)
 440                 flags |= QUICK;
 441
 442         if (options & PRUNE_SHOW_ONLY) {
 443                 flags |= VERBOSE;
 444                 write_shallow_commits_1(&sb, 0, NULL, flags);
 445                 strbuf_release(&sb);
 446                 return;
 447         }
 448         fd = hold_lock_file_for_update(&shallow_lock.lock,
 449                                        git_path_shallow(the_repository),
 450                                        LOCK_DIE_ON_ERROR);
 451         check_shallow_file_for_update(the_repository);
 452         if (write_shallow_commits_1(&sb, 0, NULL, flags)) {
 453                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 454                         die_errno("failed to write to %s",
 455                                   get_lock_file_path(&shallow_lock.lock));
 456                 commit_shallow_file(the_repository, &shallow_lock);
 457         } else {
 458                 unlink(git_path_shallow(the_repository));
 459                 rollback_shallow_file(the_repository, &shallow_lock);
 460         }
 461         strbuf_release(&sb);
 462 }
 463
 464 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
 465
 466 /*
 467  * Step 1, split sender shallow commits into "ours" and "theirs"
 468  * Step 2, clean "ours" based on .git/shallow
 469  */
 470 void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa)
 471 {
 472         trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
 473         memset(info, 0, sizeof(*info));
 474         info->shallow = sa;
 475         if (!sa)
 476                 return;
 477         ALLOC_ARRAY(info->ours, sa->nr);
 478         ALLOC_ARRAY(info->theirs, sa->nr);
 479         for (size_t i = 0; i < sa->nr; i++) {
 480                 if (odb_has_object(the_repository->objects, sa->oid + i,
 481                                    HAS_OBJECT_RECHECK_PACKED | HAS_OBJECT_FETCH_PROMISOR)) {
 482                         struct commit_graft *graft;
 483                         graft = lookup_commit_graft(the_repository,
 484                                                     &sa->oid[i]);
 485                         if (graft && graft->nr_parent < 0)
 486                                 continue;
 487                         info->ours[info->nr_ours++] = i;
 488                 } else
 489                         info->theirs[info->nr_theirs++] = i;
 490         }
 491 }
 492
 493 void clear_shallow_info(struct shallow_info *info)
 494 {
 495         if (info->used_shallow) {
 496                 for (size_t i = 0; i < info->shallow->nr; i++)
 497                         free(info->used_shallow[i]);
 498                 free(info->used_shallow);
 499         }
 500
 501         free(info->need_reachability_test);
 502         free(info->reachable);
 503         free(info->shallow_ref);
 504         free(info->ours);
 505         free(info->theirs);
 506 }
 507
 508 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
 509
 510 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 511 {
 512         struct object_id *oid = info->shallow->oid;
 513         size_t i, dst;
 514         trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
 515         for (i = dst = 0; i < info->nr_theirs; i++) {
 516                 if (i != dst)
 517                         info->theirs[dst] = info->theirs[i];
 518                 if (odb_has_object(the_repository->objects, oid + info->theirs[i],
 519                                    HAS_OBJECT_RECHECK_PACKED | HAS_OBJECT_FETCH_PROMISOR))
 520                         dst++;
 521         }
 522         info->nr_theirs = dst;
 523 }
 524
 525 define_commit_slab(ref_bitmap, uint32_t *);
 526
 527 #define POOL_SIZE (512 * 1024)
 528
 529 struct paint_info {
 530         struct ref_bitmap ref_bitmap;
 531         unsigned nr_bits;
 532         char **pools;
 533         char *free, *end;
 534         unsigned pool_count;
 535 };
 536
 537 static uint32_t *paint_alloc(struct paint_info *info)
 538 {
 539         unsigned nr = DIV_ROUND_UP(info->nr_bits, 32);
 540         unsigned size = nr * sizeof(uint32_t);
 541         void *p;
 542         if (!info->pool_count || info->end < info->free + size) {
 543                 if (size > POOL_SIZE)
 544                         BUG("pool size too small for %d in paint_alloc()",
 545                             size);
 546                 info->pool_count++;
 547                 REALLOC_ARRAY(info->pools, info->pool_count);
 548                 info->free = xmalloc(POOL_SIZE);
 549                 info->pools[info->pool_count - 1] = info->free;
 550                 info->end = info->free + POOL_SIZE;
 551         }
 552         p = info->free;
 553         info->free += size;
 554         return p;
 555 }
 556
 557 /*
 558  * Given a commit SHA-1, walk down to parents until either SEEN,
 559  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
 560  * all walked commits.
 561  */
 562 static void paint_down(struct paint_info *info, const struct object_id *oid,
 563                        unsigned int id)
 564 {
 565         unsigned int i, nr;
 566         struct commit_list *head = NULL;
 567         size_t bitmap_nr = DIV_ROUND_UP(info->nr_bits, 32);
 568         size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
 569         struct commit *c = lookup_commit_reference_gently(the_repository, oid,
 570                                                           1);
 571         uint32_t *tmp; /* to be freed before return */
 572         uint32_t *bitmap;
 573
 574         if (!c)
 575                 return;
 576
 577         tmp = xmalloc(bitmap_size);
 578         bitmap = paint_alloc(info);
 579         memset(bitmap, 0, bitmap_size);
 580         bitmap[id / 32] |= (1U << (id % 32));
 581         commit_list_insert(c, &head);
 582         while (head) {
 583                 struct commit_list *p;
 584                 struct commit *c = pop_commit(&head);
 585                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 586
 587                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
 588                 if (c->object.flags & (SEEN | UNINTERESTING))
 589                         continue;
 590                 else
 591                         c->object.flags |= SEEN;
 592
 593                 if (!*refs)
 594                         *refs = bitmap;
 595                 else {
 596                         memcpy(tmp, *refs, bitmap_size);
 597                         for (i = 0; i < bitmap_nr; i++)
 598                                 tmp[i] |= bitmap[i];
 599                         if (memcmp(tmp, *refs, bitmap_size)) {
 600                                 *refs = paint_alloc(info);
 601                                 memcpy(*refs, tmp, bitmap_size);
 602                         }
 603                 }
 604
 605                 if (c->object.flags & BOTTOM)
 606                         continue;
 607
 608                 if (repo_parse_commit(the_repository, c))
 609                         die("unable to parse commit %s",
 610                             oid_to_hex(&c->object.oid));
 611
 612                 for (p = c->parents; p; p = p->next) {
 613                         if (p->item->object.flags & SEEN)
 614                                 continue;
 615                         commit_list_insert(p->item, &head);
 616                 }
 617         }
 618
 619         nr = get_max_object_index(the_repository);
 620         for (i = 0; i < nr; i++) {
 621                 struct object *o = get_indexed_object(the_repository, i);
 622                 if (o && o->type == OBJ_COMMIT)
 623                         o->flags &= ~SEEN;
 624         }
 625
 626         free(tmp);
 627 }
 628
 629 static int mark_uninteresting(const char *refname UNUSED,
 630                               const char *referent UNUSED,
 631                               const struct object_id *oid,
 632                               int flags UNUSED,
 633                               void *cb_data UNUSED)
 634 {
 635         struct commit *commit = lookup_commit_reference_gently(the_repository,
 636                                                                oid, 1);
 637         if (!commit)
 638                 return 0;
 639         commit->object.flags |= UNINTERESTING;
 640         mark_parents_uninteresting(NULL, commit);
 641         return 0;
 642 }
 643
 644 static void post_assign_shallow(struct shallow_info *info,
 645                                 struct ref_bitmap *ref_bitmap,
 646                                 int *ref_status);
 647 /*
 648  * Step 6(+7), associate shallow commits with new refs
 649  *
 650  * info->ref must be initialized before calling this function.
 651  *
 652  * If used is not NULL, it's an array of info->shallow->nr
 653  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
 654  * m-th shallow commit from info->shallow.
 655  *
 656  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
 657  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
 658  * the ref needs some shallow commits from either info->ours or
 659  * info->theirs.
 660  */
 661 void assign_shallow_commits_to_refs(struct shallow_info *info,
 662                                     uint32_t **used, int *ref_status)
 663 {
 664         struct object_id *oid = info->shallow->oid;
 665         struct oid_array *ref = info->ref;
 666         unsigned int i, nr;
 667         size_t *shallow, nr_shallow = 0;
 668         struct paint_info pi;
 669
 670         trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
 671         ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs);
 672         for (i = 0; i < info->nr_ours; i++)
 673                 shallow[nr_shallow++] = info->ours[i];
 674         for (i = 0; i < info->nr_theirs; i++)
 675                 shallow[nr_shallow++] = info->theirs[i];
 676
 677         /*
 678          * Prepare the commit graph to track what refs can reach what
 679          * (new) shallow commits.
 680          */
 681         nr = get_max_object_index(the_repository);
 682         for (i = 0; i < nr; i++) {
 683                 struct object *o = get_indexed_object(the_repository, i);
 684                 if (!o || o->type != OBJ_COMMIT)
 685                         continue;
 686
 687                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
 688         }
 689
 690         memset(&pi, 0, sizeof(pi));
 691         init_ref_bitmap(&pi.ref_bitmap);
 692         pi.nr_bits = ref->nr;
 693
 694         /*
 695          * "--not --all" to cut short the traversal if new refs
 696          * connect to old refs. If not (e.g. force ref updates) it'll
 697          * have to go down to the current shallow commits.
 698          */
 699         refs_head_ref(get_main_ref_store(the_repository), mark_uninteresting,
 700                       NULL);
 701         refs_for_each_ref(get_main_ref_store(the_repository),
 702                           mark_uninteresting, NULL);
 703
 704         /* Mark potential bottoms so we won't go out of bound */
 705         for (i = 0; i < nr_shallow; i++) {
 706                 struct commit *c = lookup_commit(the_repository,
 707                                                  &oid[shallow[i]]);
 708                 c->object.flags |= BOTTOM;
 709         }
 710
 711         for (i = 0; i < ref->nr; i++)
 712                 paint_down(&pi, ref->oid + i, i);
 713
 714         if (used) {
 715                 int bitmap_size = DIV_ROUND_UP(pi.nr_bits, 32) * sizeof(uint32_t);
 716                 memset(used, 0, sizeof(*used) * info->shallow->nr);
 717                 for (i = 0; i < nr_shallow; i++) {
 718                         const struct commit *c = lookup_commit(the_repository,
 719                                                                &oid[shallow[i]]);
 720                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 721                         if (*map)
 722                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
 723                 }
 724                 /*
 725                  * unreachable shallow commits are not removed from
 726                  * "ours" and "theirs". The user is supposed to run
 727                  * step 7 on every ref separately and not trust "ours"
 728                  * and "theirs" any more.
 729                  */
 730         } else
 731                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
 732
 733         clear_ref_bitmap(&pi.ref_bitmap);
 734         for (i = 0; i < pi.pool_count; i++)
 735                 free(pi.pools[i]);
 736         free(pi.pools);
 737         free(shallow);
 738 }
 739
 740 struct commit_array {
 741         struct commit **commits;
 742         size_t nr, alloc;
 743 };
 744
 745 static int add_ref(const char *refname UNUSED,
 746                   const char *referent UNUSED,
 747                    const struct object_id *oid,
 748                    int flags UNUSED,
 749                    void *cb_data)
 750 {
 751         struct commit_array *ca = cb_data;
 752         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
 753         ca->commits[ca->nr] = lookup_commit_reference_gently(the_repository,
 754                                                              oid, 1);
 755         if (ca->commits[ca->nr])
 756                 ca->nr++;
 757         return 0;
 758 }
 759
 760 static void update_refstatus(int *ref_status, size_t nr, uint32_t *bitmap)
 761 {
 762         if (!ref_status)
 763                 return;
 764         for (size_t i = 0; i < nr; i++)
 765                 if (bitmap[i / 32] & (1U << (i % 32)))
 766                         ref_status[i]++;
 767 }
 768
 769 /*
 770  * Step 7, reachability test on "ours" at commit level
 771  */
 772 static void post_assign_shallow(struct shallow_info *info,
 773                                 struct ref_bitmap *ref_bitmap,
 774                                 int *ref_status)
 775 {
 776         struct object_id *oid = info->shallow->oid;
 777         struct commit *c;
 778         uint32_t **bitmap;
 779         size_t dst, i, j;
 780         size_t bitmap_nr = DIV_ROUND_UP(info->ref->nr, 32);
 781         struct commit_array ca;
 782
 783         trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
 784         if (ref_status)
 785                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
 786
 787         /* Remove unreachable shallow commits from "theirs" */
 788         for (i = dst = 0; i < info->nr_theirs; i++) {
 789                 if (i != dst)
 790                         info->theirs[dst] = info->theirs[i];
 791                 c = lookup_commit(the_repository, &oid[info->theirs[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                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 798                                 dst++;
 799                                 break;
 800                         }
 801         }
 802         info->nr_theirs = dst;
 803
 804         memset(&ca, 0, sizeof(ca));
 805         refs_head_ref(get_main_ref_store(the_repository), add_ref, &ca);
 806         refs_for_each_ref(get_main_ref_store(the_repository), add_ref, &ca);
 807
 808         /* Remove unreachable shallow commits from "ours" */
 809         for (i = dst = 0; i < info->nr_ours; i++) {
 810                 if (i != dst)
 811                         info->ours[dst] = info->ours[i];
 812                 c = lookup_commit(the_repository, &oid[info->ours[i]]);
 813                 bitmap = ref_bitmap_at(ref_bitmap, c);
 814                 if (!*bitmap)
 815                         continue;
 816                 for (j = 0; j < bitmap_nr; j++)
 817                         if (bitmap[0][j]) {
 818                                 /* Step 7, reachability test at commit level */
 819                                 int ret = repo_in_merge_bases_many(the_repository, c, ca.nr, ca.commits, 1);
 820                                 if (ret < 0)
 821                                         exit(128);
 822                                 if (!ret) {
 823                                         update_refstatus(ref_status, info->ref->nr, *bitmap);
 824                                         dst++;
 825                                         break;
 826                                 }
 827                         }
 828         }
 829         info->nr_ours = dst;
 830
 831         free(ca.commits);
 832 }
 833
 834 /* (Delayed) step 7, reachability test at commit level */
 835 int delayed_reachability_test(struct shallow_info *si, int c)
 836 {
 837         if (si->need_reachability_test[c]) {
 838                 struct commit *commit = lookup_commit(the_repository,
 839                                                       &si->shallow->oid[c]);
 840
 841                 if (!si->commits) {
 842                         struct commit_array ca;
 843
 844                         memset(&ca, 0, sizeof(ca));
 845                         refs_head_ref(get_main_ref_store(the_repository),
 846                                       add_ref, &ca);
 847                         refs_for_each_ref(get_main_ref_store(the_repository),
 848                                           add_ref, &ca);
 849                         si->commits = ca.commits;
 850                         si->nr_commits = ca.nr;
 851                 }
 852
 853                 si->reachable[c] = repo_in_merge_bases_many(the_repository,
 854                                                             commit,
 855                                                             si->nr_commits,
 856                                                             si->commits,
 857                                                             1);
 858                 if (si->reachable[c] < 0)
 859                         exit(128);
 860                 si->need_reachability_test[c] = 0;
 861         }
 862         return si->reachable[c];
 863 }