shallow.c

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