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         CALLOC_ARRAY(work, cnt);
 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         DUP_ARRAY(sorted, array, cnt);
 249         QSORT(sorted, cnt, compare_commits_by_gen);
 250         min_generation = commit_graph_generation(sorted[0]);
 251
 252         ALLOC_ARRAY(walk_start, walk_start_alloc);
 253
 254         /* Mark all parents of the input as STALE */
 255         for (i = 0; i < cnt; i++) {
 256                 struct commit_list *parents;
 257
 258                 repo_parse_commit(r, array[i]);
 259                 array[i]->object.flags |= RESULT;
 260                 parents = array[i]->parents;
 261
 262                 while (parents) {
 263                         repo_parse_commit(r, parents->item);
 264                         if (!(parents->item->object.flags & STALE)) {
 265                                 parents->item->object.flags |= STALE;
 266                                 ALLOC_GROW(walk_start, walk_start_nr + 1, walk_start_alloc);
 267                                 walk_start[walk_start_nr++] = parents->item;
 268                         }
 269                         parents = parents->next;
 270                 }
 271         }
 272
 273         QSORT(walk_start, walk_start_nr, compare_commits_by_gen);
 274
 275         /* remove STALE bit for now to allow walking through parents */
 276         for (i = 0; i < walk_start_nr; i++)
 277                 walk_start[i]->object.flags &= ~STALE;
 278
 279         /*
 280          * Start walking from the highest generation. Hopefully, it will
 281          * find all other items during the first-parent walk, and we can
 282          * terminate early. Otherwise, we will do the same amount of work
 283          * as before.
 284          */
 285         for (i = walk_start_nr - 1; i >= 0 && count_still_independent > 1; i--) {
 286                 /* push the STALE bits up to min generation */
 287                 struct commit_list *stack = NULL;
 288
 289                 commit_list_insert(walk_start[i], &stack);
 290                 walk_start[i]->object.flags |= STALE;
 291
 292                 while (stack) {
 293                         struct commit_list *parents;
 294                         struct commit *c = stack->item;
 295
 296                         repo_parse_commit(r, c);
 297
 298                         if (c->object.flags & RESULT) {
 299                                 c->object.flags &= ~RESULT;
 300                                 if (--count_still_independent <= 1)
 301                                         break;
 302                                 if (oideq(&c->object.oid, &sorted[min_gen_pos]->object.oid)) {
 303                                         while (min_gen_pos < cnt - 1 &&
 304                                                (sorted[min_gen_pos]->object.flags & STALE))
 305                                                 min_gen_pos++;
 306                                         min_generation = commit_graph_generation(sorted[min_gen_pos]);
 307                                 }
 308                         }
 309
 310                         if (commit_graph_generation(c) < min_generation) {
 311                                 pop_commit(&stack);
 312                                 continue;
 313                         }
 314
 315                         parents = c->parents;
 316                         while (parents) {
 317                                 if (!(parents->item->object.flags & STALE)) {
 318                                         parents->item->object.flags |= STALE;
 319                                         commit_list_insert(parents->item, &stack);
 320                                         break;
 321                                 }
 322                                 parents = parents->next;
 323                         }
 324
 325                         /* pop if all parents have been visited already */
 326                         if (!parents)
 327                                 pop_commit(&stack);
 328                 }
 329                 free_commit_list(stack);
 330         }
 331         free(sorted);
 332
 333         /* clear result */
 334         for (i = 0; i < cnt; i++)
 335                 array[i]->object.flags &= ~RESULT;
 336
 337         /* rearrange array */
 338         for (i = count_non_stale = 0; i < cnt; i++) {
 339                 if (!(array[i]->object.flags & STALE))
 340                         array[count_non_stale++] = array[i];
 341         }
 342
 343         /* clear marks */
 344         clear_commit_marks_many(walk_start_nr, walk_start, STALE);
 345         free(walk_start);
 346
 347         return count_non_stale;
 348 }
 349
 350 static int remove_redundant(struct repository *r, struct commit **array, int cnt)
 351 {
 352         /*
 353          * Some commit in the array may be an ancestor of
 354          * another commit.  Move the independent commits to the
 355          * beginning of 'array' and return their number. Callers
 356          * should not rely upon the contents of 'array' after
 357          * that number.
 358          */
 359         if (generation_numbers_enabled(r)) {
 360                 int i;
 361
 362                 /*
 363                  * If we have a single commit with finite generation
 364                  * number, then the _with_gen algorithm is preferred.
 365                  */
 366                 for (i = 0; i < cnt; i++) {
 367                         if (commit_graph_generation(array[i]) < GENERATION_NUMBER_INFINITY)
 368                                 return remove_redundant_with_gen(r, array, cnt);
 369                 }
 370         }
 371
 372         return remove_redundant_no_gen(r, array, cnt);
 373 }
 374
 375 static struct commit_list *get_merge_bases_many_0(struct repository *r,
 376                                                   struct commit *one,
 377                                                   int n,
 378                                                   struct commit **twos,
 379                                                   int cleanup)
 380 {
 381         struct commit_list *list;
 382         struct commit **rslt;
 383         struct commit_list *result;
 384         int cnt, i;
 385
 386         result = merge_bases_many(r, one, n, twos);
 387         for (i = 0; i < n; i++) {
 388                 if (one == twos[i])
 389                         return result;
 390         }
 391         if (!result || !result->next) {
 392                 if (cleanup) {
 393                         clear_commit_marks(one, all_flags);
 394                         clear_commit_marks_many(n, twos, all_flags);
 395                 }
 396                 return result;
 397         }
 398
 399         /* There are more than one */
 400         cnt = commit_list_count(result);
 401         CALLOC_ARRAY(rslt, cnt);
 402         for (list = result, i = 0; list; list = list->next)
 403                 rslt[i++] = list->item;
 404         free_commit_list(result);
 405
 406         clear_commit_marks(one, all_flags);
 407         clear_commit_marks_many(n, twos, all_flags);
 408
 409         cnt = remove_redundant(r, rslt, cnt);
 410         result = NULL;
 411         for (i = 0; i < cnt; i++)
 412                 commit_list_insert_by_date(rslt[i], &result);
 413         free(rslt);
 414         return result;
 415 }
 416
 417 struct commit_list *repo_get_merge_bases_many(struct repository *r,
 418                                               struct commit *one,
 419                                               int n,
 420                                               struct commit **twos)
 421 {
 422         return get_merge_bases_many_0(r, one, n, twos, 1);
 423 }
 424
 425 struct commit_list *repo_get_merge_bases_many_dirty(struct repository *r,
 426                                                     struct commit *one,
 427                                                     int n,
 428                                                     struct commit **twos)
 429 {
 430         return get_merge_bases_many_0(r, one, n, twos, 0);
 431 }
 432
 433 struct commit_list *repo_get_merge_bases(struct repository *r,
 434                                          struct commit *one,
 435                                          struct commit *two)
 436 {
 437         return get_merge_bases_many_0(r, one, 1, &two, 1);
 438 }
 439
 440 /*
 441  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 442  */
 443 int repo_is_descendant_of(struct repository *r,
 444                           struct commit *commit,
 445                           struct commit_list *with_commit)
 446 {
 447         if (!with_commit)
 448                 return 1;
 449
 450         if (generation_numbers_enabled(the_repository)) {
 451                 struct commit_list *from_list = NULL;
 452                 int result;
 453                 commit_list_insert(commit, &from_list);
 454                 result = can_all_from_reach(from_list, with_commit, 0);
 455                 free_commit_list(from_list);
 456                 return result;
 457         } else {
 458                 while (with_commit) {
 459                         struct commit *other;
 460
 461                         other = with_commit->item;
 462                         with_commit = with_commit->next;
 463                         if (repo_in_merge_bases_many(r, other, 1, &commit))
 464                                 return 1;
 465                 }
 466                 return 0;
 467         }
 468 }
 469
 470 /*
 471  * Is "commit" an ancestor of one of the "references"?
 472  */
 473 int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
 474                              int nr_reference, struct commit **reference)
 475 {
 476         struct commit_list *bases;
 477         int ret = 0, i;
 478         timestamp_t generation, max_generation = GENERATION_NUMBER_ZERO;
 479
 480         if (repo_parse_commit(r, commit))
 481                 return ret;
 482         for (i = 0; i < nr_reference; i++) {
 483                 if (repo_parse_commit(r, reference[i]))
 484                         return ret;
 485
 486                 generation = commit_graph_generation(reference[i]);
 487                 if (generation > max_generation)
 488                         max_generation = generation;
 489         }
 490
 491         generation = commit_graph_generation(commit);
 492         if (generation > max_generation)
 493                 return ret;
 494
 495         bases = paint_down_to_common(r, commit,
 496                                      nr_reference, reference,
 497                                      generation);
 498         if (commit->object.flags & PARENT2)
 499                 ret = 1;
 500         clear_commit_marks(commit, all_flags);
 501         clear_commit_marks_many(nr_reference, reference, all_flags);
 502         free_commit_list(bases);
 503         return ret;
 504 }
 505
 506 /*
 507  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 508  */
 509 int repo_in_merge_bases(struct repository *r,
 510                         struct commit *commit,
 511                         struct commit *reference)
 512 {
 513         int res;
 514         struct commit_list *list = NULL;
 515         struct commit_list **next = &list;
 516
 517         next = commit_list_append(commit, next);
 518         res = repo_is_descendant_of(r, reference, list);
 519         free_commit_list(list);
 520
 521         return res;
 522 }
 523
 524 struct commit_list *reduce_heads(struct commit_list *heads)
 525 {
 526         struct commit_list *p;
 527         struct commit_list *result = NULL, **tail = &result;
 528         struct commit **array;
 529         int num_head, i;
 530
 531         if (!heads)
 532                 return NULL;
 533
 534         /* Uniquify */
 535         for (p = heads; p; p = p->next)
 536                 p->item->object.flags &= ~STALE;
 537         for (p = heads, num_head = 0; p; p = p->next) {
 538                 if (p->item->object.flags & STALE)
 539                         continue;
 540                 p->item->object.flags |= STALE;
 541                 num_head++;
 542         }
 543         CALLOC_ARRAY(array, num_head);
 544         for (p = heads, i = 0; p; p = p->next) {
 545                 if (p->item->object.flags & STALE) {
 546                         array[i++] = p->item;
 547                         p->item->object.flags &= ~STALE;
 548                 }
 549         }
 550         num_head = remove_redundant(the_repository, array, num_head);
 551         for (i = 0; i < num_head; i++)
 552                 tail = &commit_list_insert(array[i], tail)->next;
 553         free(array);
 554         return result;
 555 }
 556
 557 void reduce_heads_replace(struct commit_list **heads)
 558 {
 559         struct commit_list *result = reduce_heads(*heads);
 560         free_commit_list(*heads);
 561         *heads = result;
 562 }
 563
 564 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 565 {
 566         struct object *o;
 567         struct commit *old_commit, *new_commit;
 568         struct commit_list *old_commit_list = NULL;
 569         int ret;
 570
 571         /*
 572          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
 573          * old_commit.  Otherwise we require --force.
 574          */
 575         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
 576                       NULL, 0);
 577         if (!o || o->type != OBJ_COMMIT)
 578                 return 0;
 579         old_commit = (struct commit *) o;
 580
 581         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
 582                       NULL, 0);
 583         if (!o || o->type != OBJ_COMMIT)
 584                 return 0;
 585         new_commit = (struct commit *) o;
 586
 587         if (parse_commit(new_commit) < 0)
 588                 return 0;
 589
 590         commit_list_insert(old_commit, &old_commit_list);
 591         ret = repo_is_descendant_of(the_repository,
 592                                     new_commit, old_commit_list);
 593         free_commit_list(old_commit_list);
 594         return ret;
 595 }
 596
 597 /*
 598  * Mimicking the real stack, this stack lives on the heap, avoiding stack
 599  * overflows.
 600  *
 601  * At each recursion step, the stack items points to the commits whose
 602  * ancestors are to be inspected.
 603  */
 604 struct contains_stack {
 605         int nr, alloc;
 606         struct contains_stack_entry {
 607                 struct commit *commit;
 608                 struct commit_list *parents;
 609         } *contains_stack;
 610 };
 611
 612 static int in_commit_list(const struct commit_list *want, struct commit *c)
 613 {
 614         for (; want; want = want->next)
 615                 if (oideq(&want->item->object.oid, &c->object.oid))
 616                         return 1;
 617         return 0;
 618 }
 619
 620 /*
 621  * Test whether the candidate is contained in the list.
 622  * Do not recurse to find out, though, but return -1 if inconclusive.
 623  */
 624 static enum contains_result contains_test(struct commit *candidate,
 625                                           const struct commit_list *want,
 626                                           struct contains_cache *cache,
 627                                           timestamp_t cutoff)
 628 {
 629         enum contains_result *cached = contains_cache_at(cache, candidate);
 630
 631         /* If we already have the answer cached, return that. */
 632         if (*cached)
 633                 return *cached;
 634
 635         /* or are we it? */
 636         if (in_commit_list(want, candidate)) {
 637                 *cached = CONTAINS_YES;
 638                 return CONTAINS_YES;
 639         }
 640
 641         /* Otherwise, we don't know; prepare to recurse */
 642         parse_commit_or_die(candidate);
 643
 644         if (commit_graph_generation(candidate) < cutoff)
 645                 return CONTAINS_NO;
 646
 647         return CONTAINS_UNKNOWN;
 648 }
 649
 650 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
 651 {
 652         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
 653         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
 654         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
 655 }
 656
 657 static enum contains_result contains_tag_algo(struct commit *candidate,
 658                                               const struct commit_list *want,
 659                                               struct contains_cache *cache)
 660 {
 661         struct contains_stack contains_stack = { 0, 0, NULL };
 662         enum contains_result result;
 663         timestamp_t cutoff = GENERATION_NUMBER_INFINITY;
 664         const struct commit_list *p;
 665
 666         for (p = want; p; p = p->next) {
 667                 timestamp_t generation;
 668                 struct commit *c = p->item;
 669                 load_commit_graph_info(the_repository, c);
 670                 generation = commit_graph_generation(c);
 671                 if (generation < cutoff)
 672                         cutoff = generation;
 673         }
 674
 675         result = contains_test(candidate, want, cache, cutoff);
 676         if (result != CONTAINS_UNKNOWN)
 677                 return result;
 678
 679         push_to_contains_stack(candidate, &contains_stack);
 680         while (contains_stack.nr) {
 681                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
 682                 struct commit *commit = entry->commit;
 683                 struct commit_list *parents = entry->parents;
 684
 685                 if (!parents) {
 686                         *contains_cache_at(cache, commit) = CONTAINS_NO;
 687                         contains_stack.nr--;
 688                 }
 689                 /*
 690                  * If we just popped the stack, parents->item has been marked,
 691                  * therefore contains_test will return a meaningful yes/no.
 692                  */
 693                 else switch (contains_test(parents->item, want, cache, cutoff)) {
 694                 case CONTAINS_YES:
 695                         *contains_cache_at(cache, commit) = CONTAINS_YES;
 696                         contains_stack.nr--;
 697                         break;
 698                 case CONTAINS_NO:
 699                         entry->parents = parents->next;
 700                         break;
 701                 case CONTAINS_UNKNOWN:
 702                         push_to_contains_stack(parents->item, &contains_stack);
 703                         break;
 704                 }
 705         }
 706         free(contains_stack.contains_stack);
 707         return contains_test(candidate, want, cache, cutoff);
 708 }
 709
 710 int commit_contains(struct ref_filter *filter, struct commit *commit,
 711                     struct commit_list *list, struct contains_cache *cache)
 712 {
 713         if (filter->with_commit_tag_algo)
 714                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
 715         return repo_is_descendant_of(the_repository, commit, list);
 716 }
 717
 718 int can_all_from_reach_with_flag(struct object_array *from,
 719                                  unsigned int with_flag,
 720                                  unsigned int assign_flag,
 721                                  time_t min_commit_date,
 722                                  timestamp_t min_generation)
 723 {
 724         struct commit **list = NULL;
 725         int i;
 726         int nr_commits;
 727         int result = 1;
 728
 729         ALLOC_ARRAY(list, from->nr);
 730         nr_commits = 0;
 731         for (i = 0; i < from->nr; i++) {
 732                 struct object *from_one = from->objects[i].item;
 733
 734                 if (!from_one || from_one->flags & assign_flag)
 735                         continue;
 736
 737                 from_one = deref_tag(the_repository, from_one,
 738                                      "a from object", 0);
 739                 if (!from_one || from_one->type != OBJ_COMMIT) {
 740                         /*
 741                          * no way to tell if this is reachable by
 742                          * looking at the ancestry chain alone, so
 743                          * leave a note to ourselves not to worry about
 744                          * this object anymore.
 745                          */
 746                         from->objects[i].item->flags |= assign_flag;
 747                         continue;
 748                 }
 749
 750                 list[nr_commits] = (struct commit *)from_one;
 751                 if (parse_commit(list[nr_commits]) ||
 752                     commit_graph_generation(list[nr_commits]) < min_generation) {
 753                         result = 0;
 754                         goto cleanup;
 755                 }
 756
 757                 nr_commits++;
 758         }
 759
 760         QSORT(list, nr_commits, compare_commits_by_gen);
 761
 762         for (i = 0; i < nr_commits; i++) {
 763                 /* DFS from list[i] */
 764                 struct commit_list *stack = NULL;
 765
 766                 list[i]->object.flags |= assign_flag;
 767                 commit_list_insert(list[i], &stack);
 768
 769                 while (stack) {
 770                         struct commit_list *parent;
 771
 772                         if (stack->item->object.flags & (with_flag | RESULT)) {
 773                                 pop_commit(&stack);
 774                                 if (stack)
 775                                         stack->item->object.flags |= RESULT;
 776                                 continue;
 777                         }
 778
 779                         for (parent = stack->item->parents; parent; parent = parent->next) {
 780                                 if (parent->item->object.flags & (with_flag | RESULT))
 781                                         stack->item->object.flags |= RESULT;
 782
 783                                 if (!(parent->item->object.flags & assign_flag)) {
 784                                         parent->item->object.flags |= assign_flag;
 785
 786                                         if (parse_commit(parent->item) ||
 787                                             parent->item->date < min_commit_date ||
 788                                             commit_graph_generation(parent->item) < min_generation)
 789                                                 continue;
 790
 791                                         commit_list_insert(parent->item, &stack);
 792                                         break;
 793                                 }
 794                         }
 795
 796                         if (!parent)
 797                                 pop_commit(&stack);
 798                 }
 799
 800                 if (!(list[i]->object.flags & (with_flag | RESULT))) {
 801                         result = 0;
 802                         goto cleanup;
 803                 }
 804         }
 805
 806 cleanup:
 807         clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
 808         free(list);
 809
 810         for (i = 0; i < from->nr; i++)
 811                 from->objects[i].item->flags &= ~assign_flag;
 812
 813         return result;
 814 }
 815
 816 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 817                        int cutoff_by_min_date)
 818 {
 819         struct object_array from_objs = OBJECT_ARRAY_INIT;
 820         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
 821         struct commit_list *from_iter = from, *to_iter = to;
 822         int result;
 823         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
 824
 825         while (from_iter) {
 826                 add_object_array(&from_iter->item->object, NULL, &from_objs);
 827
 828                 if (!parse_commit(from_iter->item)) {
 829                         timestamp_t generation;
 830                         if (from_iter->item->date < min_commit_date)
 831                                 min_commit_date = from_iter->item->date;
 832
 833                         generation = commit_graph_generation(from_iter->item);
 834                         if (generation < min_generation)
 835                                 min_generation = generation;
 836                 }
 837
 838                 from_iter = from_iter->next;
 839         }
 840
 841         while (to_iter) {
 842                 if (!parse_commit(to_iter->item)) {
 843                         timestamp_t generation;
 844                         if (to_iter->item->date < min_commit_date)
 845                                 min_commit_date = to_iter->item->date;
 846
 847                         generation = commit_graph_generation(to_iter->item);
 848                         if (generation < min_generation)
 849                                 min_generation = generation;
 850                 }
 851
 852                 to_iter->item->object.flags |= PARENT2;
 853
 854                 to_iter = to_iter->next;
 855         }
 856
 857         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
 858                                               min_commit_date, min_generation);
 859
 860         while (from) {
 861                 clear_commit_marks(from->item, PARENT1);
 862                 from = from->next;
 863         }
 864
 865         while (to) {
 866                 clear_commit_marks(to->item, PARENT2);
 867                 to = to->next;
 868         }
 869
 870         object_array_clear(&from_objs);
 871         return result;
 872 }
 873
 874 struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
 875                                          struct commit **to, int nr_to,
 876                                          unsigned int reachable_flag)
 877 {
 878         struct commit **item;
 879         struct commit *current;
 880         struct commit_list *found_commits = NULL;
 881         struct commit **to_last = to + nr_to;
 882         struct commit **from_last = from + nr_from;
 883         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
 884         int num_to_find = 0;
 885
 886         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
 887
 888         for (item = to; item < to_last; item++) {
 889                 timestamp_t generation;
 890                 struct commit *c = *item;
 891
 892                 parse_commit(c);
 893                 generation = commit_graph_generation(c);
 894                 if (generation < min_generation)
 895                         min_generation = generation;
 896
 897                 if (!(c->object.flags & PARENT1)) {
 898                         c->object.flags |= PARENT1;
 899                         num_to_find++;
 900                 }
 901         }
 902
 903         for (item = from; item < from_last; item++) {
 904                 struct commit *c = *item;
 905                 if (!(c->object.flags & PARENT2)) {
 906                         c->object.flags |= PARENT2;
 907                         parse_commit(c);
 908
 909                         prio_queue_put(&queue, *item);
 910                 }
 911         }
 912
 913         while (num_to_find && (current = prio_queue_get(&queue)) != NULL) {
 914                 struct commit_list *parents;
 915
 916                 if (current->object.flags & PARENT1) {
 917                         current->object.flags &= ~PARENT1;
 918                         current->object.flags |= reachable_flag;
 919                         commit_list_insert(current, &found_commits);
 920                         num_to_find--;
 921                 }
 922
 923                 for (parents = current->parents; parents; parents = parents->next) {
 924                         struct commit *p = parents->item;
 925
 926                         parse_commit(p);
 927
 928                         if (commit_graph_generation(p) < min_generation)
 929                                 continue;
 930
 931                         if (p->object.flags & PARENT2)
 932                                 continue;
 933
 934                         p->object.flags |= PARENT2;
 935                         prio_queue_put(&queue, p);
 936                 }
 937         }
 938
 939         clear_commit_marks_many(nr_to, to, PARENT1);
 940         clear_commit_marks_many(nr_from, from, PARENT2);
 941
 942         return found_commits;
 943 }