shallow.c

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