git.oblomov.eu Git - git/blob - commit-reach.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "commit-graph.h"
   4 #include "decorate.h"
   5 #include "prio-queue.h"
   6 #include "tree.h"
   7 #include "ref-filter.h"
   8 #include "revision.h"
   9 #include "tag.h"
  10 #include "commit-reach.h"
  11
  12 /* Remember to update object flag allocation in object.h */
  13 #define PARENT1         (1u<<16)
  14 #define PARENT2         (1u<<17)
  15 #define STALE           (1u<<18)
  16 #define RESULT          (1u<<19)
  17
  18 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
  19
  20 static int compare_commits_by_gen(const void *_a, const void *_b)
  21 {
  22         const struct commit *a = *(const struct commit * const *)_a;
  23         const struct commit *b = *(const struct commit * const *)_b;
  24
  25         timestamp_t generation_a = commit_graph_generation(a);
  26         timestamp_t generation_b = commit_graph_generation(b);
  27
  28         if (generation_a < generation_b)
  29                 return -1;
  30         if (generation_a > generation_b)
  31                 return 1;
  32         if (a->date < b->date)
  33                 return -1;
  34         if (a->date > b->date)
  35                 return 1;
  36         return 0;
  37 }
  38
  39 static int queue_has_nonstale(struct prio_queue *queue)
  40 {
  41         int i;
  42         for (i = 0; i < queue->nr; i++) {
  43                 struct commit *commit = queue->array[i].data;
  44                 if (!(commit->object.flags & STALE))
  45                         return 1;
  46         }
  47         return 0;
  48 }
  49
  50 /* all input commits in one and twos[] must have been parsed! */
  51 static struct commit_list *paint_down_to_common(struct repository *r,
  52                                                 struct commit *one, int n,
  53                                                 struct commit **twos,
  54                                                 timestamp_t min_generation)
  55 {
  56         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
  57         struct commit_list *result = NULL;
  58         int i;
  59         timestamp_t last_gen = GENERATION_NUMBER_INFINITY;
  60
  61         if (!min_generation && !corrected_commit_dates_enabled(r))
  62                 queue.compare = compare_commits_by_commit_date;
  63
  64         one->object.flags |= PARENT1;
  65         if (!n) {
  66                 commit_list_append(one, &result);
  67                 return result;
  68         }
  69         prio_queue_put(&queue, one);
  70
  71         for (i = 0; i < n; i++) {
  72                 twos[i]->object.flags |= PARENT2;
  73                 prio_queue_put(&queue, twos[i]);
  74         }
  75
  76         while (queue_has_nonstale(&queue)) {
  77                 struct commit *commit = prio_queue_get(&queue);
  78                 struct commit_list *parents;
  79                 int flags;
  80                 timestamp_t generation = commit_graph_generation(commit);
  81
  82                 if (min_generation && generation > last_gen)
  83                         BUG("bad generation skip %"PRItime" > %"PRItime" at %s",
  84                             generation, last_gen,
  85                             oid_to_hex(&commit->object.oid));
  86                 last_gen = generation;
  87
  88                 if (generation < min_generation)
  89                         break;
  90
  91                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
  92                 if (flags == (PARENT1 | PARENT2)) {
  93                         if (!(commit->object.flags & RESULT)) {
  94                                 commit->object.flags |= RESULT;
  95                                 commit_list_insert_by_date(commit, &result);
  96                         }
  97                         /* Mark parents of a found merge stale */
  98                         flags |= STALE;
  99                 }
 100                 parents = commit->parents;
 101                 while (parents) {
 102                         struct commit *p = parents->item;
 103                         parents = parents->next;
 104                         if ((p->object.flags & flags) == flags)
 105                                 continue;
 106                         if (repo_parse_commit(r, p))
 107                                 return NULL;
 108                         p->object.flags |= flags;
 109                         prio_queue_put(&queue, p);
 110                 }
 111         }
 112
 113         clear_prio_queue(&queue);
 114         return result;
 115 }
 116
 117 static struct commit_list *merge_bases_many(struct repository *r,
 118                                             struct commit *one, int n,
 119                                             struct commit **twos)
 120 {
 121         struct commit_list *list = NULL;
 122         struct commit_list *result = NULL;
 123         int i;
 124
 125         for (i = 0; i < n; i++) {
 126                 if (one == twos[i])
 127                         /*
 128                          * We do not mark this even with RESULT so we do not
 129                          * have to clean it up.
 130                          */
 131                         return commit_list_insert(one, &result);
 132         }
 133
 134         if (repo_parse_commit(r, one))
 135                 return NULL;
 136         for (i = 0; i < n; i++) {
 137                 if (repo_parse_commit(r, twos[i]))
 138                         return NULL;
 139         }
 140
 141         list = paint_down_to_common(r, one, n, twos, 0);
 142
 143         while (list) {
 144                 struct commit *commit = pop_commit(&list);
 145                 if (!(commit->object.flags & STALE))
 146                         commit_list_insert_by_date(commit, &result);
 147         }
 148         return result;
 149 }
 150
 151 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 152 {
 153         struct commit_list *i, *j, *k, *ret = NULL;
 154
 155         if (!in)
 156                 return ret;
 157
 158         commit_list_insert(in->item, &ret);
 159
 160         for (i = in->next; i; i = i->next) {
 161                 struct commit_list *new_commits = NULL, *end = NULL;
 162
 163                 for (j = ret; j; j = j->next) {
 164                         struct commit_list *bases;
 165                         bases = get_merge_bases(i->item, j->item);
 166                         if (!new_commits)
 167                                 new_commits = bases;
 168                         else
 169                                 end->next = bases;
 170                         for (k = bases; k; k = k->next)
 171                                 end = k;
 172                 }
 173                 ret = new_commits;
 174         }
 175         return ret;
 176 }
 177
 178 static int remove_redundant_no_gen(struct repository *r,
 179                                    struct commit **array, int cnt)
 180 {
 181         struct commit **work;
 182         unsigned char *redundant;
 183         int *filled_index;
 184         int i, j, filled;
 185
 186         work = xcalloc(cnt, sizeof(*work));
 187         redundant = xcalloc(cnt, 1);
 188         ALLOC_ARRAY(filled_index, cnt - 1);
 189
 190         for (i = 0; i < cnt; i++)
 191                 repo_parse_commit(r, array[i]);
 192         for (i = 0; i < cnt; i++) {
 193                 struct commit_list *common;
 194                 timestamp_t min_generation = commit_graph_generation(array[i]);
 195
 196                 if (redundant[i])
 197                         continue;
 198                 for (j = filled = 0; j < cnt; j++) {
 199                         timestamp_t curr_generation;
 200                         if (i == j || redundant[j])
 201                                 continue;
 202                         filled_index[filled] = j;
 203                         work[filled++] = array[j];
 204
 205                         curr_generation = commit_graph_generation(array[j]);
 206                         if (curr_generation < min_generation)
 207                                 min_generation = curr_generation;
 208                 }
 209                 common = paint_down_to_common(r, array[i], filled,
 210                                               work, min_generation);
 211                 if (array[i]->object.flags & PARENT2)
 212                         redundant[i] = 1;
 213                 for (j = 0; j < filled; j++)
 214                         if (work[j]->object.flags & PARENT1)
 215                                 redundant[filled_index[j]] = 1;
 216                 clear_commit_marks(array[i], all_flags);
 217                 clear_commit_marks_many(filled, work, all_flags);
 218                 free_commit_list(common);
 219         }
 220
 221         /* Now collect the result */
 222         COPY_ARRAY(work, array, cnt);
 223         for (i = filled = 0; i < cnt; i++)
 224                 if (!redundant[i])
 225                         array[filled++] = work[i];
 226         free(work);
 227         free(redundant);
 228         free(filled_index);
 229         return filled;
 230 }
 231
 232 static int remove_redundant_with_gen(struct repository *r,
 233                                      struct commit **array, int cnt)
 234 {
 235         int i, count_non_stale = 0, count_still_independent = cnt;
 236         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
 237         struct commit **walk_start, **sorted;
 238         size_t walk_start_nr = 0, walk_start_alloc = cnt;
 239         int min_gen_pos = 0;
 240
 241         /*
 242          * Sort the input by generation number, ascending. This allows
 243          * us to increase the "min_generation" limit when we discover
 244          * the commit with lowest generation is STALE. The index
 245          * min_gen_pos points to the current position within 'array'
 246          * that is not yet known to be STALE.
 247          */
 248         ALLOC_ARRAY(sorted, cnt);
 249         COPY_ARRAY(sorted, array, cnt);
 250         QSORT(sorted, cnt, compare_commits_by_gen);
 251         min_generation = commit_graph_generation(sorted[0]);
 252
 253         ALLOC_ARRAY(walk_start, walk_start_alloc);
 254
 255         /* Mark all parents of the input as STALE */
 256         for (i = 0; i < cnt; i++) {
 257                 struct commit_list *parents;
 258
 259                 repo_parse_commit(r, array[i]);
 260                 array[i]->object.flags |= RESULT;
 261                 parents = array[i]->parents;
 262
 263                 while (parents) {
 264                         repo_parse_commit(r, parents->item);
 265                         if (!(parents->item->object.flags & STALE)) {
 266                                 parents->item->object.flags |= STALE;
 267                                 ALLOC_GROW(walk_start, walk_start_nr + 1, walk_start_alloc);
 268                                 walk_start[walk_start_nr++] = parents->item;
 269                         }
 270                         parents = parents->next;
 271                 }
 272         }
 273
 274         QSORT(walk_start, walk_start_nr, compare_commits_by_gen);
 275
 276         /* remove STALE bit for now to allow walking through parents */
 277         for (i = 0; i < walk_start_nr; i++)
 278                 walk_start[i]->object.flags &= ~STALE;
 279
 280         /*
 281          * Start walking from the highest generation. Hopefully, it will
 282          * find all other items during the first-parent walk, and we can
 283          * terminate early. Otherwise, we will do the same amount of work
 284          * as before.
 285          */
 286         for (i = walk_start_nr - 1; i >= 0 && count_still_independent > 1; i--) {
 287                 /* push the STALE bits up to min generation */
 288                 struct commit_list *stack = NULL;
 289
 290                 commit_list_insert(walk_start[i], &stack);
 291                 walk_start[i]->object.flags |= STALE;
 292
 293                 while (stack) {
 294                         struct commit_list *parents;
 295                         struct commit *c = stack->item;
 296
 297                         repo_parse_commit(r, c);
 298
 299                         if (c->object.flags & RESULT) {
 300                                 c->object.flags &= ~RESULT;
 301                                 if (--count_still_independent <= 1)
 302                                         break;
 303                                 if (oideq(&c->object.oid, &sorted[min_gen_pos]->object.oid)) {
 304                                         while (min_gen_pos < cnt - 1 &&
 305                                                (sorted[min_gen_pos]->object.flags & STALE))
 306                                                 min_gen_pos++;
 307                                         min_generation = commit_graph_generation(sorted[min_gen_pos]);
 308                                 }
 309                         }
 310
 311                         if (commit_graph_generation(c) < min_generation) {
 312                                 pop_commit(&stack);
 313                                 continue;
 314                         }
 315
 316                         parents = c->parents;
 317                         while (parents) {
 318                                 if (!(parents->item->object.flags & STALE)) {
 319                                         parents->item->object.flags |= STALE;
 320                                         commit_list_insert(parents->item, &stack);
 321                                         break;
 322                                 }
 323                                 parents = parents->next;
 324                         }
 325
 326                         /* pop if all parents have been visited already */
 327                         if (!parents)
 328                                 pop_commit(&stack);
 329                 }
 330                 free_commit_list(stack);
 331         }
 332         free(sorted);
 333
 334         /* clear result */
 335         for (i = 0; i < cnt; i++)
 336                 array[i]->object.flags &= ~RESULT;
 337
 338         /* rearrange array */
 339         for (i = count_non_stale = 0; i < cnt; i++) {
 340                 if (!(array[i]->object.flags & STALE))
 341                         array[count_non_stale++] = array[i];
 342         }
 343
 344         /* clear marks */
 345         clear_commit_marks_many(walk_start_nr, walk_start, STALE);
 346         free(walk_start);
 347
 348         return count_non_stale;
 349 }
 350
 351 static int remove_redundant(struct repository *r, struct commit **array, int cnt)
 352 {
 353         /*
 354          * Some commit in the array may be an ancestor of
 355          * another commit.  Move the independent commits to the
 356          * beginning of 'array' and return their number. Callers
 357          * should not rely upon the contents of 'array' after
 358          * that number.
 359          */
 360         if (generation_numbers_enabled(r)) {
 361                 int i;
 362
 363                 /*
 364                  * If we have a single commit with finite generation
 365                  * number, then the _with_gen algorithm is preferred.
 366                  */
 367                 for (i = 0; i < cnt; i++) {
 368                         if (commit_graph_generation(array[i]) < GENERATION_NUMBER_INFINITY)
 369                                 return remove_redundant_with_gen(r, array, cnt);
 370                 }
 371         }
 372
 373         return remove_redundant_no_gen(r, array, cnt);
 374 }
 375
 376 static struct commit_list *get_merge_bases_many_0(struct repository *r,
 377                                                   struct commit *one,
 378                                                   int n,
 379                                                   struct commit **twos,
 380                                                   int cleanup)
 381 {
 382         struct commit_list *list;
 383         struct commit **rslt;
 384         struct commit_list *result;
 385         int cnt, i;
 386
 387         result = merge_bases_many(r, one, n, twos);
 388         for (i = 0; i < n; i++) {
 389                 if (one == twos[i])
 390                         return result;
 391         }
 392         if (!result || !result->next) {
 393                 if (cleanup) {
 394                         clear_commit_marks(one, all_flags);
 395                         clear_commit_marks_many(n, twos, all_flags);
 396                 }
 397                 return result;
 398         }
 399
 400         /* There are more than one */
 401         cnt = commit_list_count(result);
 402         rslt = xcalloc(cnt, sizeof(*rslt));
 403         for (list = result, i = 0; list; list = list->next)
 404                 rslt[i++] = list->item;
 405         free_commit_list(result);
 406
 407         clear_commit_marks(one, all_flags);
 408         clear_commit_marks_many(n, twos, all_flags);
 409
 410         cnt = remove_redundant(r, rslt, cnt);
 411         result = NULL;
 412         for (i = 0; i < cnt; i++)
 413                 commit_list_insert_by_date(rslt[i], &result);
 414         free(rslt);
 415         return result;
 416 }
 417
 418 struct commit_list *repo_get_merge_bases_many(struct repository *r,
 419                                               struct commit *one,
 420                                               int n,
 421                                               struct commit **twos)
 422 {
 423         return get_merge_bases_many_0(r, one, n, twos, 1);
 424 }
 425
 426 struct commit_list *repo_get_merge_bases_many_dirty(struct repository *r,
 427                                                     struct commit *one,
 428                                                     int n,
 429                                                     struct commit **twos)
 430 {
 431         return get_merge_bases_many_0(r, one, n, twos, 0);
 432 }
 433
 434 struct commit_list *repo_get_merge_bases(struct repository *r,
 435                                          struct commit *one,
 436                                          struct commit *two)
 437 {
 438         return get_merge_bases_many_0(r, one, 1, &two, 1);
 439 }
 440
 441 /*
 442  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 443  */
 444 int repo_is_descendant_of(struct repository *r,
 445                           struct commit *commit,
 446                           struct commit_list *with_commit)
 447 {
 448         if (!with_commit)
 449                 return 1;
 450
 451         if (generation_numbers_enabled(the_repository)) {
 452                 struct commit_list *from_list = NULL;
 453                 int result;
 454                 commit_list_insert(commit, &from_list);
 455                 result = can_all_from_reach(from_list, with_commit, 0);
 456                 free_commit_list(from_list);
 457                 return result;
 458         } else {
 459                 while (with_commit) {
 460                         struct commit *other;
 461
 462                         other = with_commit->item;
 463                         with_commit = with_commit->next;
 464                         if (repo_in_merge_bases_many(r, other, 1, &commit))
 465                                 return 1;
 466                 }
 467                 return 0;
 468         }
 469 }
 470
 471 /*
 472  * Is "commit" an ancestor of one of the "references"?
 473  */
 474 int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
 475                              int nr_reference, struct commit **reference)
 476 {
 477         struct commit_list *bases;
 478         int ret = 0, i;
 479         timestamp_t generation, max_generation = GENERATION_NUMBER_ZERO;
 480
 481         if (repo_parse_commit(r, commit))
 482                 return ret;
 483         for (i = 0; i < nr_reference; i++) {
 484                 if (repo_parse_commit(r, reference[i]))
 485                         return ret;
 486
 487                 generation = commit_graph_generation(reference[i]);
 488                 if (generation > max_generation)
 489                         max_generation = generation;
 490         }
 491
 492         generation = commit_graph_generation(commit);
 493         if (generation > max_generation)
 494                 return ret;
 495
 496         bases = paint_down_to_common(r, commit,
 497                                      nr_reference, reference,
 498                                      generation);
 499         if (commit->object.flags & PARENT2)
 500                 ret = 1;
 501         clear_commit_marks(commit, all_flags);
 502         clear_commit_marks_many(nr_reference, reference, all_flags);
 503         free_commit_list(bases);
 504         return ret;
 505 }
 506
 507 /*
 508  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 509  */
 510 int repo_in_merge_bases(struct repository *r,
 511                         struct commit *commit,
 512                         struct commit *reference)
 513 {
 514         int res;
 515         struct commit_list *list = NULL;
 516         struct commit_list **next = &list;
 517
 518         next = commit_list_append(commit, next);
 519         res = repo_is_descendant_of(r, reference, list);
 520         free_commit_list(list);
 521
 522         return res;
 523 }
 524
 525 struct commit_list *reduce_heads(struct commit_list *heads)
 526 {
 527         struct commit_list *p;
 528         struct commit_list *result = NULL, **tail = &result;
 529         struct commit **array;
 530         int num_head, i;
 531
 532         if (!heads)
 533                 return NULL;
 534
 535         /* Uniquify */
 536         for (p = heads; p; p = p->next)
 537                 p->item->object.flags &= ~STALE;
 538         for (p = heads, num_head = 0; p; p = p->next) {
 539                 if (p->item->object.flags & STALE)
 540                         continue;
 541                 p->item->object.flags |= STALE;
 542                 num_head++;
 543         }
 544         array = xcalloc(num_head, sizeof(*array));
 545         for (p = heads, i = 0; p; p = p->next) {
 546                 if (p->item->object.flags & STALE) {
 547                         array[i++] = p->item;
 548                         p->item->object.flags &= ~STALE;
 549                 }
 550         }
 551         num_head = remove_redundant(the_repository, array, num_head);
 552         for (i = 0; i < num_head; i++)
 553                 tail = &commit_list_insert(array[i], tail)->next;
 554         free(array);
 555         return result;
 556 }
 557
 558 void reduce_heads_replace(struct commit_list **heads)
 559 {
 560         struct commit_list *result = reduce_heads(*heads);
 561         free_commit_list(*heads);
 562         *heads = result;
 563 }
 564
 565 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 566 {
 567         struct object *o;
 568         struct commit *old_commit, *new_commit;
 569         struct commit_list *old_commit_list = NULL;
 570         int ret;
 571
 572         /*
 573          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
 574          * old_commit.  Otherwise we require --force.
 575          */
 576         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
 577                       NULL, 0);
 578         if (!o || o->type != OBJ_COMMIT)
 579                 return 0;
 580         old_commit = (struct commit *) o;
 581
 582         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
 583                       NULL, 0);
 584         if (!o || o->type != OBJ_COMMIT)
 585                 return 0;
 586         new_commit = (struct commit *) o;
 587
 588         if (parse_commit(new_commit) < 0)
 589                 return 0;
 590
 591         commit_list_insert(old_commit, &old_commit_list);
 592         ret = repo_is_descendant_of(the_repository,
 593                                     new_commit, old_commit_list);
 594         free_commit_list(old_commit_list);
 595         return ret;
 596 }
 597
 598 /*
 599  * Mimicking the real stack, this stack lives on the heap, avoiding stack
 600  * overflows.
 601  *
 602  * At each recursion step, the stack items points to the commits whose
 603  * ancestors are to be inspected.
 604  */
 605 struct contains_stack {
 606         int nr, alloc;
 607         struct contains_stack_entry {
 608                 struct commit *commit;
 609                 struct commit_list *parents;
 610         } *contains_stack;
 611 };
 612
 613 static int in_commit_list(const struct commit_list *want, struct commit *c)
 614 {
 615         for (; want; want = want->next)
 616                 if (oideq(&want->item->object.oid, &c->object.oid))
 617                         return 1;
 618         return 0;
 619 }
 620
 621 /*
 622  * Test whether the candidate is contained in the list.
 623  * Do not recurse to find out, though, but return -1 if inconclusive.
 624  */
 625 static enum contains_result contains_test(struct commit *candidate,
 626                                           const struct commit_list *want,
 627                                           struct contains_cache *cache,
 628                                           timestamp_t cutoff)
 629 {
 630         enum contains_result *cached = contains_cache_at(cache, candidate);
 631
 632         /* If we already have the answer cached, return that. */
 633         if (*cached)
 634                 return *cached;
 635
 636         /* or are we it? */
 637         if (in_commit_list(want, candidate)) {
 638                 *cached = CONTAINS_YES;
 639                 return CONTAINS_YES;
 640         }
 641
 642         /* Otherwise, we don't know; prepare to recurse */
 643         parse_commit_or_die(candidate);
 644
 645         if (commit_graph_generation(candidate) < cutoff)
 646                 return CONTAINS_NO;
 647
 648         return CONTAINS_UNKNOWN;
 649 }
 650
 651 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
 652 {
 653         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
 654         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
 655         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
 656 }
 657
 658 static enum contains_result contains_tag_algo(struct commit *candidate,
 659                                               const struct commit_list *want,
 660                                               struct contains_cache *cache)
 661 {
 662         struct contains_stack contains_stack = { 0, 0, NULL };
 663         enum contains_result result;
 664         timestamp_t cutoff = GENERATION_NUMBER_INFINITY;
 665         const struct commit_list *p;
 666
 667         for (p = want; p; p = p->next) {
 668                 timestamp_t generation;
 669                 struct commit *c = p->item;
 670                 load_commit_graph_info(the_repository, c);
 671                 generation = commit_graph_generation(c);
 672                 if (generation < cutoff)
 673                         cutoff = generation;
 674         }
 675
 676         result = contains_test(candidate, want, cache, cutoff);
 677         if (result != CONTAINS_UNKNOWN)
 678                 return result;
 679
 680         push_to_contains_stack(candidate, &contains_stack);
 681         while (contains_stack.nr) {
 682                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
 683                 struct commit *commit = entry->commit;
 684                 struct commit_list *parents = entry->parents;
 685
 686                 if (!parents) {
 687                         *contains_cache_at(cache, commit) = CONTAINS_NO;
 688                         contains_stack.nr--;
 689                 }
 690                 /*
 691                  * If we just popped the stack, parents->item has been marked,
 692                  * therefore contains_test will return a meaningful yes/no.
 693                  */
 694                 else switch (contains_test(parents->item, want, cache, cutoff)) {
 695                 case CONTAINS_YES:
 696                         *contains_cache_at(cache, commit) = CONTAINS_YES;
 697                         contains_stack.nr--;
 698                         break;
 699                 case CONTAINS_NO:
 700                         entry->parents = parents->next;
 701                         break;
 702                 case CONTAINS_UNKNOWN:
 703                         push_to_contains_stack(parents->item, &contains_stack);
 704                         break;
 705                 }
 706         }
 707         free(contains_stack.contains_stack);
 708         return contains_test(candidate, want, cache, cutoff);
 709 }
 710
 711 int commit_contains(struct ref_filter *filter, struct commit *commit,
 712                     struct commit_list *list, struct contains_cache *cache)
 713 {
 714         if (filter->with_commit_tag_algo)
 715                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
 716         return repo_is_descendant_of(the_repository, commit, list);
 717 }
 718
 719 int can_all_from_reach_with_flag(struct object_array *from,
 720                                  unsigned int with_flag,
 721                                  unsigned int assign_flag,
 722                                  time_t min_commit_date,
 723                                  timestamp_t min_generation)
 724 {
 725         struct commit **list = NULL;
 726         int i;
 727         int nr_commits;
 728         int result = 1;
 729
 730         ALLOC_ARRAY(list, from->nr);
 731         nr_commits = 0;
 732         for (i = 0; i < from->nr; i++) {
 733                 struct object *from_one = from->objects[i].item;
 734
 735                 if (!from_one || from_one->flags & assign_flag)
 736                         continue;
 737
 738                 from_one = deref_tag(the_repository, from_one,
 739                                      "a from object", 0);
 740                 if (!from_one || from_one->type != OBJ_COMMIT) {
 741                         /*
 742                          * no way to tell if this is reachable by
 743                          * looking at the ancestry chain alone, so
 744                          * leave a note to ourselves not to worry about
 745                          * this object anymore.
 746                          */
 747                         from->objects[i].item->flags |= assign_flag;
 748                         continue;
 749                 }
 750
 751                 list[nr_commits] = (struct commit *)from_one;
 752                 if (parse_commit(list[nr_commits]) ||
 753                     commit_graph_generation(list[nr_commits]) < min_generation) {
 754                         result = 0;
 755                         goto cleanup;
 756                 }
 757
 758                 nr_commits++;
 759         }
 760
 761         QSORT(list, nr_commits, compare_commits_by_gen);
 762
 763         for (i = 0; i < nr_commits; i++) {
 764                 /* DFS from list[i] */
 765                 struct commit_list *stack = NULL;
 766
 767                 list[i]->object.flags |= assign_flag;
 768                 commit_list_insert(list[i], &stack);
 769
 770                 while (stack) {
 771                         struct commit_list *parent;
 772
 773                         if (stack->item->object.flags & (with_flag | RESULT)) {
 774                                 pop_commit(&stack);
 775                                 if (stack)
 776                                         stack->item->object.flags |= RESULT;
 777                                 continue;
 778                         }
 779
 780                         for (parent = stack->item->parents; parent; parent = parent->next) {
 781                                 if (parent->item->object.flags & (with_flag | RESULT))
 782                                         stack->item->object.flags |= RESULT;
 783
 784                                 if (!(parent->item->object.flags & assign_flag)) {
 785                                         parent->item->object.flags |= assign_flag;
 786
 787                                         if (parse_commit(parent->item) ||
 788                                             parent->item->date < min_commit_date ||
 789                                             commit_graph_generation(parent->item) < min_generation)
 790                                                 continue;
 791
 792                                         commit_list_insert(parent->item, &stack);
 793                                         break;
 794                                 }
 795                         }
 796
 797                         if (!parent)
 798                                 pop_commit(&stack);
 799                 }
 800
 801                 if (!(list[i]->object.flags & (with_flag | RESULT))) {
 802                         result = 0;
 803                         goto cleanup;
 804                 }
 805         }
 806
 807 cleanup:
 808         clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
 809         free(list);
 810
 811         for (i = 0; i < from->nr; i++)
 812                 from->objects[i].item->flags &= ~assign_flag;
 813
 814         return result;
 815 }
 816
 817 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 818                        int cutoff_by_min_date)
 819 {
 820         struct object_array from_objs = OBJECT_ARRAY_INIT;
 821         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
 822         struct commit_list *from_iter = from, *to_iter = to;
 823         int result;
 824         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
 825
 826         while (from_iter) {
 827                 add_object_array(&from_iter->item->object, NULL, &from_objs);
 828
 829                 if (!parse_commit(from_iter->item)) {
 830                         timestamp_t generation;
 831                         if (from_iter->item->date < min_commit_date)
 832                                 min_commit_date = from_iter->item->date;
 833
 834                         generation = commit_graph_generation(from_iter->item);
 835                         if (generation < min_generation)
 836                                 min_generation = generation;
 837                 }
 838
 839                 from_iter = from_iter->next;
 840         }
 841
 842         while (to_iter) {
 843                 if (!parse_commit(to_iter->item)) {
 844                         timestamp_t generation;
 845                         if (to_iter->item->date < min_commit_date)
 846                                 min_commit_date = to_iter->item->date;
 847
 848                         generation = commit_graph_generation(to_iter->item);
 849                         if (generation < min_generation)
 850                                 min_generation = generation;
 851                 }
 852
 853                 to_iter->item->object.flags |= PARENT2;
 854
 855                 to_iter = to_iter->next;
 856         }
 857
 858         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
 859                                               min_commit_date, min_generation);
 860
 861         while (from) {
 862                 clear_commit_marks(from->item, PARENT1);
 863                 from = from->next;
 864         }
 865
 866         while (to) {
 867                 clear_commit_marks(to->item, PARENT2);
 868                 to = to->next;
 869         }
 870
 871         object_array_clear(&from_objs);
 872         return result;
 873 }
 874
 875 struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
 876                                          struct commit **to, int nr_to,
 877                                          unsigned int reachable_flag)
 878 {
 879         struct commit **item;
 880         struct commit *current;
 881         struct commit_list *found_commits = NULL;
 882         struct commit **to_last = to + nr_to;
 883         struct commit **from_last = from + nr_from;
 884         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
 885         int num_to_find = 0;
 886
 887         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
 888
 889         for (item = to; item < to_last; item++) {
 890                 timestamp_t generation;
 891                 struct commit *c = *item;
 892
 893                 parse_commit(c);
 894                 generation = commit_graph_generation(c);
 895                 if (generation < min_generation)
 896                         min_generation = generation;
 897
 898                 if (!(c->object.flags & PARENT1)) {
 899                         c->object.flags |= PARENT1;
 900                         num_to_find++;
 901                 }
 902         }
 903
 904         for (item = from; item < from_last; item++) {
 905                 struct commit *c = *item;
 906                 if (!(c->object.flags & PARENT2)) {
 907                         c->object.flags |= PARENT2;
 908                         parse_commit(c);
 909
 910                         prio_queue_put(&queue, *item);
 911                 }
 912         }
 913
 914         while (num_to_find && (current = prio_queue_get(&queue)) != NULL) {
 915                 struct commit_list *parents;
 916
 917                 if (current->object.flags & PARENT1) {
 918                         current->object.flags &= ~PARENT1;
 919                         current->object.flags |= reachable_flag;
 920                         commit_list_insert(current, &found_commits);
 921                         num_to_find--;
 922                 }
 923
 924                 for (parents = current->parents; parents; parents = parents->next) {
 925                         struct commit *p = parents->item;
 926
 927                         parse_commit(p);
 928
 929                         if (commit_graph_generation(p) < min_generation)
 930                                 continue;
 931
 932                         if (p->object.flags & PARENT2)
 933                                 continue;
 934
 935                         p->object.flags |= PARENT2;
 936                         prio_queue_put(&queue, p);
 937                 }
 938         }
 939
 940         clear_commit_marks_many(nr_to, to, PARENT1);
 941         clear_commit_marks_many(nr_from, from, PARENT2);
 942
 943         return found_commits;
 944 }