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