shallow.c

   1 #include "cache.h"
   2 #include "repository.h"
   3 #include "tempfile.h"
   4 #include "lockfile.h"
   5 #include "object-store.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "pkt-line.h"
   9 #include "remote.h"
  10 #include "refs.h"
  11 #include "sha1-array.h"
  12 #include "diff.h"
  13 #include "revision.h"
  14 #include "commit-slab.h"
  15 #include "revision.h"
  16 #include "list-objects.h"
  17 #include "commit-slab.h"
  18 #include "repository.h"
  19 #include "commit-reach.h"
  20
  21 void set_alternate_shallow_file(struct repository *r, const char *path, int override)
  22 {
  23         if (r->parsed_objects->is_shallow != -1)
  24                 BUG("is_repository_shallow must not be called before set_alternate_shallow_file");
  25         if (r->parsed_objects->alternate_shallow_file && !override)
  26                 return;
  27         free(r->parsed_objects->alternate_shallow_file);
  28         r->parsed_objects->alternate_shallow_file = xstrdup_or_null(path);
  29 }
  30
  31 int register_shallow(struct repository *r, const struct object_id *oid)
  32 {
  33         struct commit_graft *graft =
  34                 xmalloc(sizeof(struct commit_graft));
  35         struct commit *commit = lookup_commit(the_repository, oid);
  36
  37         oidcpy(&graft->oid, oid);
  38         graft->nr_parent = -1;
  39         if (commit && commit->object.parsed)
  40                 commit->parents = NULL;
  41         return register_commit_graft(r, graft, 0);
  42 }
  43
  44 int is_repository_shallow(struct repository *r)
  45 {
  46         FILE *fp;
  47         char buf[1024];
  48         const char *path = r->parsed_objects->alternate_shallow_file;
  49
  50         if (r->parsed_objects->is_shallow >= 0)
  51                 return r->parsed_objects->is_shallow;
  52
  53         if (!path)
  54                 path = git_path_shallow(r);
  55         /*
  56          * fetch-pack sets '--shallow-file ""' as an indicator that no
  57          * shallow file should be used. We could just open it and it
  58          * will likely fail. But let's do an explicit check instead.
  59          */
  60         if (!*path || (fp = fopen(path, "r")) == NULL) {
  61                 stat_validity_clear(r->parsed_objects->shallow_stat);
  62                 r->parsed_objects->is_shallow = 0;
  63                 return r->parsed_objects->is_shallow;
  64         }
  65         stat_validity_update(r->parsed_objects->shallow_stat, fileno(fp));
  66         r->parsed_objects->is_shallow = 1;
  67
  68         while (fgets(buf, sizeof(buf), fp)) {
  69                 struct object_id oid;
  70                 if (get_oid_hex(buf, &oid))
  71                         die("bad shallow line: %s", buf);
  72                 register_shallow(r, &oid);
  73         }
  74         fclose(fp);
  75         return r->parsed_objects->is_shallow;
  76 }
  77
  78 /*
  79  * TODO: use "int" elemtype instead of "int *" when/if commit-slab
  80  * supports a "valid" flag.
  81  */
  82 define_commit_slab(commit_depth, int *);
  83 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
  84                 int shallow_flag, int not_shallow_flag)
  85 {
  86         int i = 0, cur_depth = 0;
  87         struct commit_list *result = NULL;
  88         struct object_array stack = OBJECT_ARRAY_INIT;
  89         struct commit *commit = NULL;
  90         struct commit_graft *graft;
  91         struct commit_depth depths;
  92
  93         init_commit_depth(&depths);
  94         while (commit || i < heads->nr || stack.nr) {
  95                 struct commit_list *p;
  96                 if (!commit) {
  97                         if (i < heads->nr) {
  98                                 int **depth_slot;
  99                                 commit = (struct commit *)
 100                                         deref_tag(the_repository,
 101                                                   heads->objects[i++].item,
 102                                                   NULL, 0);
 103                                 if (!commit || commit->object.type != OBJ_COMMIT) {
 104                                         commit = NULL;
 105                                         continue;
 106                                 }
 107                                 depth_slot = commit_depth_at(&depths, commit);
 108                                 if (!*depth_slot)
 109                                         *depth_slot = xmalloc(sizeof(int));
 110                                 **depth_slot = 0;
 111                                 cur_depth = 0;
 112                         } else {
 113                                 commit = (struct commit *)
 114                                         object_array_pop(&stack);
 115                                 cur_depth = **commit_depth_at(&depths, commit);
 116                         }
 117                 }
 118                 parse_commit_or_die(commit);
 119                 cur_depth++;
 120                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
 121                     (is_repository_shallow(the_repository) && !commit->parents &&
 122                      (graft = lookup_commit_graft(the_repository, &commit->object.oid)) != NULL &&
 123                      graft->nr_parent < 0)) {
 124                         commit_list_insert(commit, &result);
 125                         commit->object.flags |= shallow_flag;
 126                         commit = NULL;
 127                         continue;
 128                 }
 129                 commit->object.flags |= not_shallow_flag;
 130                 for (p = commit->parents, commit = NULL; p; p = p->next) {
 131                         int **depth_slot = commit_depth_at(&depths, p->item);
 132                         if (!*depth_slot) {
 133                                 *depth_slot = xmalloc(sizeof(int));
 134                                 **depth_slot = cur_depth;
 135                         } else {
 136                                 if (cur_depth >= **depth_slot)
 137                                         continue;
 138                                 **depth_slot = cur_depth;
 139                         }
 140                         if (p->next)
 141                                 add_object_array(&p->item->object,
 142                                                 NULL, &stack);
 143                         else {
 144                                 commit = p->item;
 145                                 cur_depth = **commit_depth_at(&depths, commit);
 146                         }
 147                 }
 148         }
 149         for (i = 0; i < depths.slab_count; i++) {
 150                 int j;
 151
 152                 for (j = 0; j < depths.slab_size; j++)
 153                         free(depths.slab[i][j]);
 154         }
 155         clear_commit_depth(&depths);
 156
 157         return result;
 158 }
 159
 160 static void show_commit(struct commit *commit, void *data)
 161 {
 162         commit_list_insert(commit, data);
 163 }
 164
 165 /*
 166  * Given rev-list arguments, run rev-list. All reachable commits
 167  * except border ones are marked with not_shallow_flag. Border commits
 168  * are marked with shallow_flag. The list of border/shallow commits
 169  * are also returned.
 170  */
 171 struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av,
 172                                                     int shallow_flag,
 173                                                     int not_shallow_flag)
 174 {
 175         struct commit_list *result = NULL, *p;
 176         struct commit_list *not_shallow_list = NULL;
 177         struct rev_info revs;
 178         int both_flags = shallow_flag | not_shallow_flag;
 179
 180         /*
 181          * SHALLOW (excluded) and NOT_SHALLOW (included) should not be
 182          * set at this point. But better be safe than sorry.
 183          */
 184         clear_object_flags(both_flags);
 185
 186         is_repository_shallow(the_repository); /* make sure shallows are read */
 187
 188         init_revisions(&revs, NULL);
 189         save_commit_buffer = 0;
 190         setup_revisions(ac, av, &revs, NULL);
 191
 192         if (prepare_revision_walk(&revs))
 193                 die("revision walk setup failed");
 194         traverse_commit_list(&revs, show_commit, NULL, &not_shallow_list);
 195
 196         if (!not_shallow_list)
 197                 die("no commits selected for shallow requests");
 198
 199         /* Mark all reachable commits as NOT_SHALLOW */
 200         for (p = not_shallow_list; p; p = p->next)
 201                 p->item->object.flags |= not_shallow_flag;
 202
 203         /*
 204          * mark border commits SHALLOW + NOT_SHALLOW.
 205          * We cannot clear NOT_SHALLOW right now. Imagine border
 206          * commit A is processed first, then commit B, whose parent is
 207          * A, later. If NOT_SHALLOW on A is cleared at step 1, B
 208          * itself is considered border at step 2, which is incorrect.
 209          */
 210         for (p = not_shallow_list; p; p = p->next) {
 211                 struct commit *c = p->item;
 212                 struct commit_list *parent;
 213
 214                 if (parse_commit(c))
 215                         die("unable to parse commit %s",
 216                             oid_to_hex(&c->object.oid));
 217
 218                 for (parent = c->parents; parent; parent = parent->next)
 219                         if (!(parent->item->object.flags & not_shallow_flag)) {
 220                                 c->object.flags |= shallow_flag;
 221                                 commit_list_insert(c, &result);
 222                                 break;
 223                         }
 224         }
 225         free_commit_list(not_shallow_list);
 226
 227         /*
 228          * Now we can clean up NOT_SHALLOW on border commits. Having
 229          * both flags set can confuse the caller.
 230          */
 231         for (p = result; p; p = p->next) {
 232                 struct object *o = &p->item->object;
 233                 if ((o->flags & both_flags) == both_flags)
 234                         o->flags &= ~not_shallow_flag;
 235         }
 236         return result;
 237 }
 238
 239 static void check_shallow_file_for_update(struct repository *r)
 240 {
 241         if (r->parsed_objects->is_shallow == -1)
 242                 BUG("shallow must be initialized by now");
 243
 244         if (!stat_validity_check(r->parsed_objects->shallow_stat, git_path_shallow(the_repository)))
 245                 die("shallow file has changed since we read it");
 246 }
 247
 248 #define SEEN_ONLY 1
 249 #define VERBOSE   2
 250
 251 struct write_shallow_data {
 252         struct strbuf *out;
 253         int use_pack_protocol;
 254         int count;
 255         unsigned flags;
 256 };
 257
 258 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 259 {
 260         struct write_shallow_data *data = cb_data;
 261         const char *hex = oid_to_hex(&graft->oid);
 262         if (graft->nr_parent != -1)
 263                 return 0;
 264         if (data->flags & SEEN_ONLY) {
 265                 struct commit *c = lookup_commit(the_repository, &graft->oid);
 266                 if (!c || !(c->object.flags & SEEN)) {
 267                         if (data->flags & VERBOSE)
 268                                 printf("Removing %s from .git/shallow\n",
 269                                        oid_to_hex(&c->object.oid));
 270                         return 0;
 271                 }
 272         }
 273         data->count++;
 274         if (data->use_pack_protocol)
 275                 packet_buf_write(data->out, "shallow %s", hex);
 276         else {
 277                 strbuf_addstr(data->out, hex);
 278                 strbuf_addch(data->out, '\n');
 279         }
 280         return 0;
 281 }
 282
 283 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
 284                                    const struct oid_array *extra,
 285                                    unsigned flags)
 286 {
 287         struct write_shallow_data data;
 288         int i;
 289         data.out = out;
 290         data.use_pack_protocol = use_pack_protocol;
 291         data.count = 0;
 292         data.flags = flags;
 293         for_each_commit_graft(write_one_shallow, &data);
 294         if (!extra)
 295                 return data.count;
 296         for (i = 0; i < extra->nr; i++) {
 297                 strbuf_addstr(out, oid_to_hex(extra->oid + i));
 298                 strbuf_addch(out, '\n');
 299                 data.count++;
 300         }
 301         return data.count;
 302 }
 303
 304 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
 305                           const struct oid_array *extra)
 306 {
 307         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
 308 }
 309
 310 const char *setup_temporary_shallow(const struct oid_array *extra)
 311 {
 312         struct tempfile *temp;
 313         struct strbuf sb = STRBUF_INIT;
 314
 315         if (write_shallow_commits(&sb, 0, extra)) {
 316                 temp = xmks_tempfile(git_path("shallow_XXXXXX"));
 317
 318                 if (write_in_full(temp->fd, sb.buf, sb.len) < 0 ||
 319                     close_tempfile_gently(temp) < 0)
 320                         die_errno("failed to write to %s",
 321                                   get_tempfile_path(temp));
 322                 strbuf_release(&sb);
 323                 return get_tempfile_path(temp);
 324         }
 325         /*
 326          * is_repository_shallow() sees empty string as "no shallow
 327          * file".
 328          */
 329         return "";
 330 }
 331
 332 void setup_alternate_shallow(struct lock_file *shallow_lock,
 333                              const char **alternate_shallow_file,
 334                              const struct oid_array *extra)
 335 {
 336         struct strbuf sb = STRBUF_INIT;
 337         int fd;
 338
 339         fd = hold_lock_file_for_update(shallow_lock,
 340                                        git_path_shallow(the_repository),
 341                                        LOCK_DIE_ON_ERROR);
 342         check_shallow_file_for_update(the_repository);
 343         if (write_shallow_commits(&sb, 0, extra)) {
 344                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 345                         die_errno("failed to write to %s",
 346                                   get_lock_file_path(shallow_lock));
 347                 *alternate_shallow_file = get_lock_file_path(shallow_lock);
 348         } else
 349                 /*
 350                  * is_repository_shallow() sees empty string as "no
 351                  * shallow file".
 352                  */
 353                 *alternate_shallow_file = "";
 354         strbuf_release(&sb);
 355 }
 356
 357 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
 358 {
 359         int fd = *(int *)cb;
 360         if (graft->nr_parent == -1)
 361                 packet_write_fmt(fd, "shallow %s\n", oid_to_hex(&graft->oid));
 362         return 0;
 363 }
 364
 365 void advertise_shallow_grafts(int fd)
 366 {
 367         if (!is_repository_shallow(the_repository))
 368                 return;
 369         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
 370 }
 371
 372 /*
 373  * mark_reachable_objects() should have been run prior to this and all
 374  * reachable commits marked as "SEEN".
 375  */
 376 void prune_shallow(int show_only)
 377 {
 378         struct lock_file shallow_lock = LOCK_INIT;
 379         struct strbuf sb = STRBUF_INIT;
 380         int fd;
 381
 382         if (show_only) {
 383                 write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY | VERBOSE);
 384                 strbuf_release(&sb);
 385                 return;
 386         }
 387         fd = hold_lock_file_for_update(&shallow_lock,
 388                                        git_path_shallow(the_repository),
 389                                        LOCK_DIE_ON_ERROR);
 390         check_shallow_file_for_update(the_repository);
 391         if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
 392                 if (write_in_full(fd, sb.buf, sb.len) < 0)
 393                         die_errno("failed to write to %s",
 394                                   get_lock_file_path(&shallow_lock));
 395                 commit_lock_file(&shallow_lock);
 396         } else {
 397                 unlink(git_path_shallow(the_repository));
 398                 rollback_lock_file(&shallow_lock);
 399         }
 400         strbuf_release(&sb);
 401 }
 402
 403 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
 404
 405 /*
 406  * Step 1, split sender shallow commits into "ours" and "theirs"
 407  * Step 2, clean "ours" based on .git/shallow
 408  */
 409 void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa)
 410 {
 411         int i;
 412         trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
 413         memset(info, 0, sizeof(*info));
 414         info->shallow = sa;
 415         if (!sa)
 416                 return;
 417         ALLOC_ARRAY(info->ours, sa->nr);
 418         ALLOC_ARRAY(info->theirs, sa->nr);
 419         for (i = 0; i < sa->nr; i++) {
 420                 if (has_object_file(sa->oid + i)) {
 421                         struct commit_graft *graft;
 422                         graft = lookup_commit_graft(the_repository,
 423                                                     &sa->oid[i]);
 424                         if (graft && graft->nr_parent < 0)
 425                                 continue;
 426                         info->ours[info->nr_ours++] = i;
 427                 } else
 428                         info->theirs[info->nr_theirs++] = i;
 429         }
 430 }
 431
 432 void clear_shallow_info(struct shallow_info *info)
 433 {
 434         free(info->ours);
 435         free(info->theirs);
 436 }
 437
 438 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
 439
 440 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 441 {
 442         struct object_id *oid = info->shallow->oid;
 443         int i, dst;
 444         trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
 445         for (i = dst = 0; i < info->nr_theirs; i++) {
 446                 if (i != dst)
 447                         info->theirs[dst] = info->theirs[i];
 448                 if (has_object_file(oid + info->theirs[i]))
 449                         dst++;
 450         }
 451         info->nr_theirs = dst;
 452 }
 453
 454 define_commit_slab(ref_bitmap, uint32_t *);
 455
 456 #define POOL_SIZE (512 * 1024)
 457
 458 struct paint_info {
 459         struct ref_bitmap ref_bitmap;
 460         unsigned nr_bits;
 461         char **pools;
 462         char *free, *end;
 463         unsigned pool_count;
 464 };
 465
 466 static uint32_t *paint_alloc(struct paint_info *info)
 467 {
 468         unsigned nr = DIV_ROUND_UP(info->nr_bits, 32);
 469         unsigned size = nr * sizeof(uint32_t);
 470         void *p;
 471         if (!info->pool_count || size > info->end - info->free) {
 472                 if (size > POOL_SIZE)
 473                         BUG("pool size too small for %d in paint_alloc()",
 474                             size);
 475                 info->pool_count++;
 476                 REALLOC_ARRAY(info->pools, info->pool_count);
 477                 info->free = xmalloc(POOL_SIZE);
 478                 info->pools[info->pool_count - 1] = info->free;
 479                 info->end = info->free + POOL_SIZE;
 480         }
 481         p = info->free;
 482         info->free += size;
 483         return p;
 484 }
 485
 486 /*
 487  * Given a commit SHA-1, walk down to parents until either SEEN,
 488  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
 489  * all walked commits.
 490  */
 491 static void paint_down(struct paint_info *info, const struct object_id *oid,
 492                        unsigned int id)
 493 {
 494         unsigned int i, nr;
 495         struct commit_list *head = NULL;
 496         int bitmap_nr = DIV_ROUND_UP(info->nr_bits, 32);
 497         size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
 498         struct commit *c = lookup_commit_reference_gently(the_repository, oid,
 499                                                           1);
 500         uint32_t *tmp; /* to be freed before return */
 501         uint32_t *bitmap;
 502
 503         if (!c)
 504                 return;
 505
 506         tmp = xmalloc(bitmap_size);
 507         bitmap = paint_alloc(info);
 508         memset(bitmap, 0, bitmap_size);
 509         bitmap[id / 32] |= (1U << (id % 32));
 510         commit_list_insert(c, &head);
 511         while (head) {
 512                 struct commit_list *p;
 513                 struct commit *c = pop_commit(&head);
 514                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 515
 516                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
 517                 if (c->object.flags & (SEEN | UNINTERESTING))
 518                         continue;
 519                 else
 520                         c->object.flags |= SEEN;
 521
 522                 if (*refs == NULL)
 523                         *refs = bitmap;
 524                 else {
 525                         memcpy(tmp, *refs, bitmap_size);
 526                         for (i = 0; i < bitmap_nr; i++)
 527                                 tmp[i] |= bitmap[i];
 528                         if (memcmp(tmp, *refs, bitmap_size)) {
 529                                 *refs = paint_alloc(info);
 530                                 memcpy(*refs, tmp, bitmap_size);
 531                         }
 532                 }
 533
 534                 if (c->object.flags & BOTTOM)
 535                         continue;
 536
 537                 if (parse_commit(c))
 538                         die("unable to parse commit %s",
 539                             oid_to_hex(&c->object.oid));
 540
 541                 for (p = c->parents; p; p = p->next) {
 542                         if (p->item->object.flags & SEEN)
 543                                 continue;
 544                         commit_list_insert(p->item, &head);
 545                 }
 546         }
 547
 548         nr = get_max_object_index();
 549         for (i = 0; i < nr; i++) {
 550                 struct object *o = get_indexed_object(i);
 551                 if (o && o->type == OBJ_COMMIT)
 552                         o->flags &= ~SEEN;
 553         }
 554
 555         free(tmp);
 556 }
 557
 558 static int mark_uninteresting(const char *refname, const struct object_id *oid,
 559                               int flags, void *cb_data)
 560 {
 561         struct commit *commit = lookup_commit_reference_gently(the_repository,
 562                                                                oid, 1);
 563         if (!commit)
 564                 return 0;
 565         commit->object.flags |= UNINTERESTING;
 566         mark_parents_uninteresting(commit);
 567         return 0;
 568 }
 569
 570 static void post_assign_shallow(struct shallow_info *info,
 571                                 struct ref_bitmap *ref_bitmap,
 572                                 int *ref_status);
 573 /*
 574  * Step 6(+7), associate shallow commits with new refs
 575  *
 576  * info->ref must be initialized before calling this function.
 577  *
 578  * If used is not NULL, it's an array of info->shallow->nr
 579  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
 580  * m-th shallow commit from info->shallow.
 581  *
 582  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
 583  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
 584  * the ref needs some shallow commits from either info->ours or
 585  * info->theirs.
 586  */
 587 void assign_shallow_commits_to_refs(struct shallow_info *info,
 588                                     uint32_t **used, int *ref_status)
 589 {
 590         struct object_id *oid = info->shallow->oid;
 591         struct oid_array *ref = info->ref;
 592         unsigned int i, nr;
 593         int *shallow, nr_shallow = 0;
 594         struct paint_info pi;
 595
 596         trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
 597         ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs);
 598         for (i = 0; i < info->nr_ours; i++)
 599                 shallow[nr_shallow++] = info->ours[i];
 600         for (i = 0; i < info->nr_theirs; i++)
 601                 shallow[nr_shallow++] = info->theirs[i];
 602
 603         /*
 604          * Prepare the commit graph to track what refs can reach what
 605          * (new) shallow commits.
 606          */
 607         nr = get_max_object_index();
 608         for (i = 0; i < nr; i++) {
 609                 struct object *o = get_indexed_object(i);
 610                 if (!o || o->type != OBJ_COMMIT)
 611                         continue;
 612
 613                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
 614         }
 615
 616         memset(&pi, 0, sizeof(pi));
 617         init_ref_bitmap(&pi.ref_bitmap);
 618         pi.nr_bits = ref->nr;
 619
 620         /*
 621          * "--not --all" to cut short the traversal if new refs
 622          * connect to old refs. If not (e.g. force ref updates) it'll
 623          * have to go down to the current shallow commits.
 624          */
 625         head_ref(mark_uninteresting, NULL);
 626         for_each_ref(mark_uninteresting, NULL);
 627
 628         /* Mark potential bottoms so we won't go out of bound */
 629         for (i = 0; i < nr_shallow; i++) {
 630                 struct commit *c = lookup_commit(the_repository,
 631                                                  &oid[shallow[i]]);
 632                 c->object.flags |= BOTTOM;
 633         }
 634
 635         for (i = 0; i < ref->nr; i++)
 636                 paint_down(&pi, ref->oid + i, i);
 637
 638         if (used) {
 639                 int bitmap_size = DIV_ROUND_UP(pi.nr_bits, 32) * sizeof(uint32_t);
 640                 memset(used, 0, sizeof(*used) * info->shallow->nr);
 641                 for (i = 0; i < nr_shallow; i++) {
 642                         const struct commit *c = lookup_commit(the_repository,
 643                                                                &oid[shallow[i]]);
 644                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 645                         if (*map)
 646                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
 647                 }
 648                 /*
 649                  * unreachable shallow commits are not removed from
 650                  * "ours" and "theirs". The user is supposed to run
 651                  * step 7 on every ref separately and not trust "ours"
 652                  * and "theirs" any more.
 653                  */
 654         } else
 655                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
 656
 657         clear_ref_bitmap(&pi.ref_bitmap);
 658         for (i = 0; i < pi.pool_count; i++)
 659                 free(pi.pools[i]);
 660         free(pi.pools);
 661         free(shallow);
 662 }
 663
 664 struct commit_array {
 665         struct commit **commits;
 666         int nr, alloc;
 667 };
 668
 669 static int add_ref(const char *refname, const struct object_id *oid,
 670                    int flags, void *cb_data)
 671 {
 672         struct commit_array *ca = cb_data;
 673         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
 674         ca->commits[ca->nr] = lookup_commit_reference_gently(the_repository,
 675                                                              oid, 1);
 676         if (ca->commits[ca->nr])
 677                 ca->nr++;
 678         return 0;
 679 }
 680
 681 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
 682 {
 683         unsigned int i;
 684         if (!ref_status)
 685                 return;
 686         for (i = 0; i < nr; i++)
 687                 if (bitmap[i / 32] & (1U << (i % 32)))
 688                         ref_status[i]++;
 689 }
 690
 691 /*
 692  * Step 7, reachability test on "ours" at commit level
 693  */
 694 static void post_assign_shallow(struct shallow_info *info,
 695                                 struct ref_bitmap *ref_bitmap,
 696                                 int *ref_status)
 697 {
 698         struct object_id *oid = info->shallow->oid;
 699         struct commit *c;
 700         uint32_t **bitmap;
 701         int dst, i, j;
 702         int bitmap_nr = DIV_ROUND_UP(info->ref->nr, 32);
 703         struct commit_array ca;
 704
 705         trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
 706         if (ref_status)
 707                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
 708
 709         /* Remove unreachable shallow commits from "theirs" */
 710         for (i = dst = 0; i < info->nr_theirs; i++) {
 711                 if (i != dst)
 712                         info->theirs[dst] = info->theirs[i];
 713                 c = lookup_commit(the_repository, &oid[info->theirs[i]]);
 714                 bitmap = ref_bitmap_at(ref_bitmap, c);
 715                 if (!*bitmap)
 716                         continue;
 717                 for (j = 0; j < bitmap_nr; j++)
 718                         if (bitmap[0][j]) {
 719                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 720                                 dst++;
 721                                 break;
 722                         }
 723         }
 724         info->nr_theirs = dst;
 725
 726         memset(&ca, 0, sizeof(ca));
 727         head_ref(add_ref, &ca);
 728         for_each_ref(add_ref, &ca);
 729
 730         /* Remove unreachable shallow commits from "ours" */
 731         for (i = dst = 0; i < info->nr_ours; i++) {
 732                 if (i != dst)
 733                         info->ours[dst] = info->ours[i];
 734                 c = lookup_commit(the_repository, &oid[info->ours[i]]);
 735                 bitmap = ref_bitmap_at(ref_bitmap, c);
 736                 if (!*bitmap)
 737                         continue;
 738                 for (j = 0; j < bitmap_nr; j++)
 739                         if (bitmap[0][j] &&
 740                             /* Step 7, reachability test at commit level */
 741                             !in_merge_bases_many(c, ca.nr, ca.commits)) {
 742                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 743                                 dst++;
 744                                 break;
 745                         }
 746         }
 747         info->nr_ours = dst;
 748
 749         free(ca.commits);
 750 }
 751
 752 /* (Delayed) step 7, reachability test at commit level */
 753 int delayed_reachability_test(struct shallow_info *si, int c)
 754 {
 755         if (si->need_reachability_test[c]) {
 756                 struct commit *commit = lookup_commit(the_repository,
 757                                                       &si->shallow->oid[c]);
 758
 759                 if (!si->commits) {
 760                         struct commit_array ca;
 761
 762                         memset(&ca, 0, sizeof(ca));
 763                         head_ref(add_ref, &ca);
 764                         for_each_ref(add_ref, &ca);
 765                         si->commits = ca.commits;
 766                         si->nr_commits = ca.nr;
 767                 }
 768
 769                 si->reachable[c] = in_merge_bases_many(commit,
 770                                                        si->nr_commits,
 771                                                        si->commits);
 772                 si->need_reachability_test[c] = 0;
 773         }
 774         return si->reachable[c];
 775 }