shallow.c

   1 #include "cache.h"
   2 #include "lockfile.h"
   3 #include "commit.h"
   4 #include "tag.h"
   5 #include "pkt-line.h"
   6 #include "remote.h"
   7 #include "refs.h"
   8 #include "sha1-array.h"
   9 #include "diff.h"
  10 #include "revision.h"
  11 #include "commit-slab.h"
  12 #include "sigchain.h"
  13
  14 static int is_shallow = -1;
  15 static struct stat_validity shallow_stat;
  16 static char *alternate_shallow_file;
  17
  18 void set_alternate_shallow_file(const char *path, int override)
  19 {
  20         if (is_shallow != -1)
  21                 die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
  22         if (alternate_shallow_file && !override)
  23                 return;
  24         free(alternate_shallow_file);
  25         alternate_shallow_file = xstrdup_or_null(path);
  26 }
  27
  28 int register_shallow(const unsigned char *sha1)
  29 {
  30         struct commit_graft *graft =
  31                 xmalloc(sizeof(struct commit_graft));
  32         struct commit *commit = lookup_commit(sha1);
  33
  34         hashcpy(graft->oid.hash, sha1);
  35         graft->nr_parent = -1;
  36         if (commit && commit->object.parsed)
  37                 commit->parents = NULL;
  38         return register_commit_graft(graft, 0);
  39 }
  40
  41 int is_repository_shallow(void)
  42 {
  43         FILE *fp;
  44         char buf[1024];
  45         const char *path = alternate_shallow_file;
  46
  47         if (is_shallow >= 0)
  48                 return is_shallow;
  49
  50         if (!path)
  51                 path = git_path_shallow();
  52         /*
  53          * fetch-pack sets '--shallow-file ""' as an indicator that no
  54          * shallow file should be used. We could just open it and it
  55          * will likely fail. But let's do an explicit check instead.
  56          */
  57         if (!*path || (fp = fopen(path, "r")) == NULL) {
  58                 stat_validity_clear(&shallow_stat);
  59                 is_shallow = 0;
  60                 return is_shallow;
  61         }
  62         stat_validity_update(&shallow_stat, fileno(fp));
  63         is_shallow = 1;
  64
  65         while (fgets(buf, sizeof(buf), fp)) {
  66                 unsigned char sha1[20];
  67                 if (get_sha1_hex(buf, sha1))
  68                         die("bad shallow line: %s", buf);
  69                 register_shallow(sha1);
  70         }
  71         fclose(fp);
  72         return is_shallow;
  73 }
  74
  75 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
  76                 int shallow_flag, int not_shallow_flag)
  77 {
  78         int i = 0, cur_depth = 0;
  79         struct commit_list *result = NULL;
  80         struct object_array stack = OBJECT_ARRAY_INIT;
  81         struct commit *commit = NULL;
  82         struct commit_graft *graft;
  83
  84         while (commit || i < heads->nr || stack.nr) {
  85                 struct commit_list *p;
  86                 if (!commit) {
  87                         if (i < heads->nr) {
  88                                 commit = (struct commit *)
  89                                         deref_tag(heads->objects[i++].item, NULL, 0);
  90                                 if (!commit || commit->object.type != OBJ_COMMIT) {
  91                                         commit = NULL;
  92                                         continue;
  93                                 }
  94                                 if (!commit->util)
  95                                         commit->util = xmalloc(sizeof(int));
  96                                 *(int *)commit->util = 0;
  97                                 cur_depth = 0;
  98                         } else {
  99                                 commit = (struct commit *)
 100                                         stack.objects[--stack.nr].item;
 101                                 cur_depth = *(int *)commit->util;
 102                         }
 103                 }
 104                 parse_commit_or_die(commit);
 105                 cur_depth++;
 106                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
 107                     (is_repository_shallow() && !commit->parents &&
 108                      (graft = lookup_commit_graft(commit->object.sha1)) != NULL &&
 109                      graft->nr_parent < 0)) {
 110                         commit_list_insert(commit, &result);
 111                         commit->object.flags |= shallow_flag;
 112                         commit = NULL;
 113                         continue;
 114                 }
 115                 commit->object.flags |= not_shallow_flag;
 116                 for (p = commit->parents, commit = NULL; p; p = p->next) {
 117                         if (!p->item->util) {
 118                                 int *pointer = xmalloc(sizeof(int));
 119                                 p->item->util = pointer;
 120                                 *pointer =  cur_depth;
 121                         } else {
 122                                 int *pointer = p->item->util;
 123                                 if (cur_depth >= *pointer)
 124                                         continue;
 125                                 *pointer = cur_depth;
 126                         }
 127                         if (p->next)
 128                                 add_object_array(&p->item->object,
 129                                                 NULL, &stack);
 130                         else {
 131                                 commit = p->item;
 132                                 cur_depth = *(int *)commit->util;
 133                         }
 134                 }
 135         }
 136
 137         return result;
 138 }
 139
 140 static void check_shallow_file_for_update(void)
 141 {
 142         if (is_shallow == -1)
 143                 die("BUG: shallow must be initialized by now");
 144
 145         if (!stat_validity_check(&shallow_stat, git_path_shallow()))
 146                 die("shallow file has changed since we read it");
 147 }
 148
 149 #define SEEN_ONLY 1
 150 #define VERBOSE   2
 151
 152 struct write_shallow_data {
 153         struct strbuf *out;
 154         int use_pack_protocol;
 155         int count;
 156         unsigned flags;
 157 };
 158
 159 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 160 {
 161         struct write_shallow_data *data = cb_data;
 162         const char *hex = oid_to_hex(&graft->oid);
 163         if (graft->nr_parent != -1)
 164                 return 0;
 165         if (data->flags & SEEN_ONLY) {
 166                 struct commit *c = lookup_commit(graft->oid.hash);
 167                 if (!c || !(c->object.flags & SEEN)) {
 168                         if (data->flags & VERBOSE)
 169                                 printf("Removing %s from .git/shallow\n",
 170                                        sha1_to_hex(c->object.sha1));
 171                         return 0;
 172                 }
 173         }
 174         data->count++;
 175         if (data->use_pack_protocol)
 176                 packet_buf_write(data->out, "shallow %s", hex);
 177         else {
 178                 strbuf_addstr(data->out, hex);
 179                 strbuf_addch(data->out, '\n');
 180         }
 181         return 0;
 182 }
 183
 184 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
 185                                    const struct sha1_array *extra,
 186                                    unsigned flags)
 187 {
 188         struct write_shallow_data data;
 189         int i;
 190         data.out = out;
 191         data.use_pack_protocol = use_pack_protocol;
 192         data.count = 0;
 193         data.flags = flags;
 194         for_each_commit_graft(write_one_shallow, &data);
 195         if (!extra)
 196                 return data.count;
 197         for (i = 0; i < extra->nr; i++) {
 198                 strbuf_addstr(out, sha1_to_hex(extra->sha1[i]));
 199                 strbuf_addch(out, '\n');
 200                 data.count++;
 201         }
 202         return data.count;
 203 }
 204
 205 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
 206                           const struct sha1_array *extra)
 207 {
 208         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
 209 }
 210
 211 static struct strbuf temporary_shallow = STRBUF_INIT;
 212
 213 static void remove_temporary_shallow(void)
 214 {
 215         if (temporary_shallow.len) {
 216                 unlink_or_warn(temporary_shallow.buf);
 217                 strbuf_reset(&temporary_shallow);
 218         }
 219 }
 220
 221 static void remove_temporary_shallow_on_signal(int signo)
 222 {
 223         remove_temporary_shallow();
 224         sigchain_pop(signo);
 225         raise(signo);
 226 }
 227
 228 const char *setup_temporary_shallow(const struct sha1_array *extra)
 229 {
 230         struct strbuf sb = STRBUF_INIT;
 231         int fd;
 232
 233         if (temporary_shallow.len)
 234                 die("BUG: attempt to create two temporary shallow files");
 235
 236         if (write_shallow_commits(&sb, 0, extra)) {
 237                 strbuf_addstr(&temporary_shallow, git_path("shallow_XXXXXX"));
 238                 fd = xmkstemp(temporary_shallow.buf);
 239
 240                 atexit(remove_temporary_shallow);
 241                 sigchain_push_common(remove_temporary_shallow_on_signal);
 242
 243                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 244                         die_errno("failed to write to %s",
 245                                   temporary_shallow.buf);
 246                 close(fd);
 247                 strbuf_release(&sb);
 248                 return temporary_shallow.buf;
 249         }
 250         /*
 251          * is_repository_shallow() sees empty string as "no shallow
 252          * file".
 253          */
 254         return temporary_shallow.buf;
 255 }
 256
 257 void setup_alternate_shallow(struct lock_file *shallow_lock,
 258                              const char **alternate_shallow_file,
 259                              const struct sha1_array *extra)
 260 {
 261         struct strbuf sb = STRBUF_INIT;
 262         int fd;
 263
 264         fd = hold_lock_file_for_update(shallow_lock, git_path_shallow(),
 265                                        LOCK_DIE_ON_ERROR);
 266         check_shallow_file_for_update();
 267         if (write_shallow_commits(&sb, 0, extra)) {
 268                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 269                         die_errno("failed to write to %s",
 270                                   shallow_lock->filename.buf);
 271                 *alternate_shallow_file = shallow_lock->filename.buf;
 272         } else
 273                 /*
 274                  * is_repository_shallow() sees empty string as "no
 275                  * shallow file".
 276                  */
 277                 *alternate_shallow_file = "";
 278         strbuf_release(&sb);
 279 }
 280
 281 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
 282 {
 283         int fd = *(int *)cb;
 284         if (graft->nr_parent == -1)
 285                 packet_write(fd, "shallow %s\n", oid_to_hex(&graft->oid));
 286         return 0;
 287 }
 288
 289 void advertise_shallow_grafts(int fd)
 290 {
 291         if (!is_repository_shallow())
 292                 return;
 293         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
 294 }
 295
 296 /*
 297  * mark_reachable_objects() should have been run prior to this and all
 298  * reachable commits marked as "SEEN".
 299  */
 300 void prune_shallow(int show_only)
 301 {
 302         static struct lock_file shallow_lock;
 303         struct strbuf sb = STRBUF_INIT;
 304         int fd;
 305
 306         if (show_only) {
 307                 write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY | VERBOSE);
 308                 strbuf_release(&sb);
 309                 return;
 310         }
 311         fd = hold_lock_file_for_update(&shallow_lock, git_path_shallow(),
 312                                        LOCK_DIE_ON_ERROR);
 313         check_shallow_file_for_update();
 314         if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
 315                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
 316                         die_errno("failed to write to %s",
 317                                   shallow_lock.filename.buf);
 318                 commit_lock_file(&shallow_lock);
 319         } else {
 320                 unlink(git_path_shallow());
 321                 rollback_lock_file(&shallow_lock);
 322         }
 323         strbuf_release(&sb);
 324 }
 325
 326 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
 327
 328 /*
 329  * Step 1, split sender shallow commits into "ours" and "theirs"
 330  * Step 2, clean "ours" based on .git/shallow
 331  */
 332 void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
 333 {
 334         int i;
 335         trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
 336         memset(info, 0, sizeof(*info));
 337         info->shallow = sa;
 338         if (!sa)
 339                 return;
 340         info->ours = xmalloc(sizeof(*info->ours) * sa->nr);
 341         info->theirs = xmalloc(sizeof(*info->theirs) * sa->nr);
 342         for (i = 0; i < sa->nr; i++) {
 343                 if (has_sha1_file(sa->sha1[i])) {
 344                         struct commit_graft *graft;
 345                         graft = lookup_commit_graft(sa->sha1[i]);
 346                         if (graft && graft->nr_parent < 0)
 347                                 continue;
 348                         info->ours[info->nr_ours++] = i;
 349                 } else
 350                         info->theirs[info->nr_theirs++] = i;
 351         }
 352 }
 353
 354 void clear_shallow_info(struct shallow_info *info)
 355 {
 356         free(info->ours);
 357         free(info->theirs);
 358 }
 359
 360 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
 361
 362 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 363 {
 364         unsigned char (*sha1)[20] = info->shallow->sha1;
 365         int i, dst;
 366         trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
 367         for (i = dst = 0; i < info->nr_theirs; i++) {
 368                 if (i != dst)
 369                         info->theirs[dst] = info->theirs[i];
 370                 if (has_sha1_file(sha1[info->theirs[i]]))
 371                         dst++;
 372         }
 373         info->nr_theirs = dst;
 374 }
 375
 376 define_commit_slab(ref_bitmap, uint32_t *);
 377
 378 struct paint_info {
 379         struct ref_bitmap ref_bitmap;
 380         unsigned nr_bits;
 381         char **slab;
 382         char *free, *end;
 383         unsigned slab_count;
 384 };
 385
 386 static uint32_t *paint_alloc(struct paint_info *info)
 387 {
 388         unsigned nr = (info->nr_bits + 31) / 32;
 389         unsigned size = nr * sizeof(uint32_t);
 390         void *p;
 391         if (!info->slab_count || info->free + size > info->end) {
 392                 info->slab_count++;
 393                 REALLOC_ARRAY(info->slab, info->slab_count);
 394                 info->free = xmalloc(COMMIT_SLAB_SIZE);
 395                 info->slab[info->slab_count - 1] = info->free;
 396                 info->end = info->free + COMMIT_SLAB_SIZE;
 397         }
 398         p = info->free;
 399         info->free += size;
 400         return p;
 401 }
 402
 403 /*
 404  * Given a commit SHA-1, walk down to parents until either SEEN,
 405  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
 406  * all walked commits.
 407  */
 408 static void paint_down(struct paint_info *info, const unsigned char *sha1,
 409                        int id)
 410 {
 411         unsigned int i, nr;
 412         struct commit_list *head = NULL;
 413         int bitmap_nr = (info->nr_bits + 31) / 32;
 414         int bitmap_size = bitmap_nr * sizeof(uint32_t);
 415         uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
 416         uint32_t *bitmap = paint_alloc(info);
 417         struct commit *c = lookup_commit_reference_gently(sha1, 1);
 418         if (!c)
 419                 return;
 420         memset(bitmap, 0, bitmap_size);
 421         bitmap[id / 32] |= (1 << (id % 32));
 422         commit_list_insert(c, &head);
 423         while (head) {
 424                 struct commit_list *p;
 425                 struct commit *c = head->item;
 426                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
 427
 428                 p = head;
 429                 head = head->next;
 430                 free(p);
 431
 432                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
 433                 if (c->object.flags & (SEEN | UNINTERESTING))
 434                         continue;
 435                 else
 436                         c->object.flags |= SEEN;
 437
 438                 if (*refs == NULL)
 439                         *refs = bitmap;
 440                 else {
 441                         memcpy(tmp, *refs, bitmap_size);
 442                         for (i = 0; i < bitmap_nr; i++)
 443                                 tmp[i] |= bitmap[i];
 444                         if (memcmp(tmp, *refs, bitmap_size)) {
 445                                 *refs = paint_alloc(info);
 446                                 memcpy(*refs, tmp, bitmap_size);
 447                         }
 448                 }
 449
 450                 if (c->object.flags & BOTTOM)
 451                         continue;
 452
 453                 if (parse_commit(c))
 454                         die("unable to parse commit %s",
 455                             sha1_to_hex(c->object.sha1));
 456
 457                 for (p = c->parents; p; p = p->next) {
 458                         uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
 459                                                           p->item);
 460                         if (p->item->object.flags & SEEN)
 461                                 continue;
 462                         if (*p_refs == NULL || *p_refs == *refs)
 463                                 *p_refs = *refs;
 464                         commit_list_insert(p->item, &head);
 465                 }
 466         }
 467
 468         nr = get_max_object_index();
 469         for (i = 0; i < nr; i++) {
 470                 struct object *o = get_indexed_object(i);
 471                 if (o && o->type == OBJ_COMMIT)
 472                         o->flags &= ~SEEN;
 473         }
 474
 475         free(tmp);
 476 }
 477
 478 static int mark_uninteresting(const char *refname, const struct object_id *oid,
 479                               int flags, void *cb_data)
 480 {
 481         struct commit *commit = lookup_commit_reference_gently(oid->hash, 1);
 482         if (!commit)
 483                 return 0;
 484         commit->object.flags |= UNINTERESTING;
 485         mark_parents_uninteresting(commit);
 486         return 0;
 487 }
 488
 489 static void post_assign_shallow(struct shallow_info *info,
 490                                 struct ref_bitmap *ref_bitmap,
 491                                 int *ref_status);
 492 /*
 493  * Step 6(+7), associate shallow commits with new refs
 494  *
 495  * info->ref must be initialized before calling this function.
 496  *
 497  * If used is not NULL, it's an array of info->shallow->nr
 498  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
 499  * m-th shallow commit from info->shallow.
 500  *
 501  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
 502  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
 503  * the ref needs some shallow commits from either info->ours or
 504  * info->theirs.
 505  */
 506 void assign_shallow_commits_to_refs(struct shallow_info *info,
 507                                     uint32_t **used, int *ref_status)
 508 {
 509         unsigned char (*sha1)[20] = info->shallow->sha1;
 510         struct sha1_array *ref = info->ref;
 511         unsigned int i, nr;
 512         int *shallow, nr_shallow = 0;
 513         struct paint_info pi;
 514
 515         trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
 516         shallow = xmalloc(sizeof(*shallow) * (info->nr_ours + info->nr_theirs));
 517         for (i = 0; i < info->nr_ours; i++)
 518                 shallow[nr_shallow++] = info->ours[i];
 519         for (i = 0; i < info->nr_theirs; i++)
 520                 shallow[nr_shallow++] = info->theirs[i];
 521
 522         /*
 523          * Prepare the commit graph to track what refs can reach what
 524          * (new) shallow commits.
 525          */
 526         nr = get_max_object_index();
 527         for (i = 0; i < nr; i++) {
 528                 struct object *o = get_indexed_object(i);
 529                 if (!o || o->type != OBJ_COMMIT)
 530                         continue;
 531
 532                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
 533         }
 534
 535         memset(&pi, 0, sizeof(pi));
 536         init_ref_bitmap(&pi.ref_bitmap);
 537         pi.nr_bits = ref->nr;
 538
 539         /*
 540          * "--not --all" to cut short the traversal if new refs
 541          * connect to old refs. If not (e.g. force ref updates) it'll
 542          * have to go down to the current shallow commits.
 543          */
 544         head_ref(mark_uninteresting, NULL);
 545         for_each_ref(mark_uninteresting, NULL);
 546
 547         /* Mark potential bottoms so we won't go out of bound */
 548         for (i = 0; i < nr_shallow; i++) {
 549                 struct commit *c = lookup_commit(sha1[shallow[i]]);
 550                 c->object.flags |= BOTTOM;
 551         }
 552
 553         for (i = 0; i < ref->nr; i++)
 554                 paint_down(&pi, ref->sha1[i], i);
 555
 556         if (used) {
 557                 int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
 558                 memset(used, 0, sizeof(*used) * info->shallow->nr);
 559                 for (i = 0; i < nr_shallow; i++) {
 560                         const struct commit *c = lookup_commit(sha1[shallow[i]]);
 561                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 562                         if (*map)
 563                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
 564                 }
 565                 /*
 566                  * unreachable shallow commits are not removed from
 567                  * "ours" and "theirs". The user is supposed to run
 568                  * step 7 on every ref separately and not trust "ours"
 569                  * and "theirs" any more.
 570                  */
 571         } else
 572                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
 573
 574         clear_ref_bitmap(&pi.ref_bitmap);
 575         for (i = 0; i < pi.slab_count; i++)
 576                 free(pi.slab[i]);
 577         free(pi.slab);
 578         free(shallow);
 579 }
 580
 581 struct commit_array {
 582         struct commit **commits;
 583         int nr, alloc;
 584 };
 585
 586 static int add_ref(const char *refname, const struct object_id *oid,
 587                    int flags, void *cb_data)
 588 {
 589         struct commit_array *ca = cb_data;
 590         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
 591         ca->commits[ca->nr] = lookup_commit_reference_gently(oid->hash, 1);
 592         if (ca->commits[ca->nr])
 593                 ca->nr++;
 594         return 0;
 595 }
 596
 597 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
 598 {
 599         int i;
 600         if (!ref_status)
 601                 return;
 602         for (i = 0; i < nr; i++)
 603                 if (bitmap[i / 32] & (1 << (i % 32)))
 604                         ref_status[i]++;
 605 }
 606
 607 /*
 608  * Step 7, reachability test on "ours" at commit level
 609  */
 610 static void post_assign_shallow(struct shallow_info *info,
 611                                 struct ref_bitmap *ref_bitmap,
 612                                 int *ref_status)
 613 {
 614         unsigned char (*sha1)[20] = info->shallow->sha1;
 615         struct commit *c;
 616         uint32_t **bitmap;
 617         int dst, i, j;
 618         int bitmap_nr = (info->ref->nr + 31) / 32;
 619         struct commit_array ca;
 620
 621         trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
 622         if (ref_status)
 623                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
 624
 625         /* Remove unreachable shallow commits from "theirs" */
 626         for (i = dst = 0; i < info->nr_theirs; i++) {
 627                 if (i != dst)
 628                         info->theirs[dst] = info->theirs[i];
 629                 c = lookup_commit(sha1[info->theirs[i]]);
 630                 bitmap = ref_bitmap_at(ref_bitmap, c);
 631                 if (!*bitmap)
 632                         continue;
 633                 for (j = 0; j < bitmap_nr; j++)
 634                         if (bitmap[0][j]) {
 635                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 636                                 dst++;
 637                                 break;
 638                         }
 639         }
 640         info->nr_theirs = dst;
 641
 642         memset(&ca, 0, sizeof(ca));
 643         head_ref(add_ref, &ca);
 644         for_each_ref(add_ref, &ca);
 645
 646         /* Remove unreachable shallow commits from "ours" */
 647         for (i = dst = 0; i < info->nr_ours; i++) {
 648                 if (i != dst)
 649                         info->ours[dst] = info->ours[i];
 650                 c = lookup_commit(sha1[info->ours[i]]);
 651                 bitmap = ref_bitmap_at(ref_bitmap, c);
 652                 if (!*bitmap)
 653                         continue;
 654                 for (j = 0; j < bitmap_nr; j++)
 655                         if (bitmap[0][j] &&
 656                             /* Step 7, reachability test at commit level */
 657                             !in_merge_bases_many(c, ca.nr, ca.commits)) {
 658                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
 659                                 dst++;
 660                                 break;
 661                         }
 662         }
 663         info->nr_ours = dst;
 664
 665         free(ca.commits);
 666 }
 667
 668 /* (Delayed) step 7, reachability test at commit level */
 669 int delayed_reachability_test(struct shallow_info *si, int c)
 670 {
 671         if (si->need_reachability_test[c]) {
 672                 struct commit *commit = lookup_commit(si->shallow->sha1[c]);
 673
 674                 if (!si->commits) {
 675                         struct commit_array ca;
 676
 677                         memset(&ca, 0, sizeof(ca));
 678                         head_ref(add_ref, &ca);
 679                         for_each_ref(add_ref, &ca);
 680                         si->commits = ca.commits;
 681                         si->nr_commits = ca.nr;
 682                 }
 683
 684                 si->reachable[c] = in_merge_bases_many(commit,
 685                                                        si->nr_commits,
 686                                                        si->commits);
 687                 si->need_reachability_test[c] = 0;
 688         }
 689         return si->reachable[c];
 690 }