commit-reach.c

   1 #include "git-compat-util.h"
   2 #include "alloc.h"
   3 #include "commit.h"
   4 #include "commit-graph.h"
   5 #include "decorate.h"
   6 #include "hex.h"
   7 #include "prio-queue.h"
   8 #include "tree.h"
   9 #include "ref-filter.h"
  10 #include "revision.h"
  11 #include "tag.h"
  12 #include "commit-reach.h"
  13
  14 /* Remember to update object flag allocation in object.h */
  15 #define PARENT1         (1u<<16)
  16 #define PARENT2         (1u<<17)
  17 #define STALE           (1u<<18)
  18 #define RESULT          (1u<<19)
  19
  20 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
  21
  22 static int compare_commits_by_gen(const void *_a, const void *_b)
  23 {
  24         const struct commit *a = *(const struct commit * const *)_a;
  25         const struct commit *b = *(const struct commit * const *)_b;
  26
  27         timestamp_t generation_a = commit_graph_generation(a);
  28         timestamp_t generation_b = commit_graph_generation(b);
  29
  30         if (generation_a < generation_b)
  31                 return -1;
  32         if (generation_a > generation_b)
  33                 return 1;
  34         if (a->date < b->date)
  35                 return -1;
  36         if (a->date > b->date)
  37                 return 1;
  38         return 0;
  39 }
  40
  41 static int queue_has_nonstale(struct prio_queue *queue)
  42 {
  43         int i;
  44         for (i = 0; i < queue->nr; i++) {
  45                 struct commit *commit = queue->array[i].data;
  46                 if (!(commit->object.flags & STALE))
  47                         return 1;
  48         }
  49         return 0;
  50 }
  51
  52 /* all input commits in one and twos[] must have been parsed! */
  53 static struct commit_list *paint_down_to_common(struct repository *r,
  54                                                 struct commit *one, int n,
  55                                                 struct commit **twos,
  56                                                 timestamp_t min_generation)
  57 {
  58         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
  59         struct commit_list *result = NULL;
  60         int i;
  61         timestamp_t last_gen = GENERATION_NUMBER_INFINITY;
  62
  63         if (!min_generation && !corrected_commit_dates_enabled(r))
  64                 queue.compare = compare_commits_by_commit_date;
  65
  66         one->object.flags |= PARENT1;
  67         if (!n) {
  68                 commit_list_append(one, &result);
  69                 return result;
  70         }
  71         prio_queue_put(&queue, one);
  72
  73         for (i = 0; i < n; i++) {
  74                 twos[i]->object.flags |= PARENT2;
  75                 prio_queue_put(&queue, twos[i]);
  76         }
  77
  78         while (queue_has_nonstale(&queue)) {
  79                 struct commit *commit = prio_queue_get(&queue);
  80                 struct commit_list *parents;
  81                 int flags;
  82                 timestamp_t generation = commit_graph_generation(commit);
  83
  84                 if (min_generation && generation > last_gen)
  85                         BUG("bad generation skip %"PRItime" > %"PRItime" at %s",
  86                             generation, last_gen,
  87                             oid_to_hex(&commit->object.oid));
  88                 last_gen = generation;
  89
  90                 if (generation < min_generation)
  91                         break;
  92
  93                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
  94                 if (flags == (PARENT1 | PARENT2)) {
  95                         if (!(commit->object.flags & RESULT)) {
  96                                 commit->object.flags |= RESULT;
  97                                 commit_list_insert_by_date(commit, &result);
  98                         }
  99                         /* Mark parents of a found merge stale */
 100                         flags |= STALE;
 101                 }
 102                 parents = commit->parents;
 103                 while (parents) {
 104                         struct commit *p = parents->item;
 105                         parents = parents->next;
 106                         if ((p->object.flags & flags) == flags)
 107                                 continue;
 108                         if (repo_parse_commit(r, p))
 109                                 return NULL;
 110                         p->object.flags |= flags;
 111                         prio_queue_put(&queue, p);
 112                 }
 113         }
 114
 115         clear_prio_queue(&queue);
 116         return result;
 117 }
 118
 119 static struct commit_list *merge_bases_many(struct repository *r,
 120                                             struct commit *one, int n,
 121                                             struct commit **twos)
 122 {
 123         struct commit_list *list = NULL;
 124         struct commit_list *result = NULL;
 125         int i;
 126
 127         for (i = 0; i < n; i++) {
 128                 if (one == twos[i])
 129                         /*
 130                          * We do not mark this even with RESULT so we do not
 131                          * have to clean it up.
 132                          */
 133                         return commit_list_insert(one, &result);
 134         }
 135
 136         if (repo_parse_commit(r, one))
 137                 return NULL;
 138         for (i = 0; i < n; i++) {
 139                 if (repo_parse_commit(r, twos[i]))
 140                         return NULL;
 141         }
 142
 143         list = paint_down_to_common(r, one, n, twos, 0);
 144
 145         while (list) {
 146                 struct commit *commit = pop_commit(&list);
 147                 if (!(commit->object.flags & STALE))
 148                         commit_list_insert_by_date(commit, &result);
 149         }
 150         return result;
 151 }
 152
 153 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 154 {
 155         struct commit_list *i, *j, *k, *ret = NULL;
 156
 157         if (!in)
 158                 return ret;
 159
 160         commit_list_insert(in->item, &ret);
 161
 162         for (i = in->next; i; i = i->next) {
 163                 struct commit_list *new_commits = NULL, *end = NULL;
 164
 165                 for (j = ret; j; j = j->next) {
 166                         struct commit_list *bases;
 167                         bases = get_merge_bases(i->item, j->item);
 168                         if (!new_commits)
 169                                 new_commits = bases;
 170                         else
 171                                 end->next = bases;
 172                         for (k = bases; k; k = k->next)
 173                                 end = k;
 174                 }
 175                 ret = new_commits;
 176         }
 177         return ret;
 178 }
 179
 180 static int remove_redundant_no_gen(struct repository *r,
 181                                    struct commit **array, int cnt)
 182 {
 183         struct commit **work;
 184         unsigned char *redundant;
 185         int *filled_index;
 186         int i, j, filled;
 187
 188         CALLOC_ARRAY(work, cnt);
 189         redundant = xcalloc(cnt, 1);
 190         ALLOC_ARRAY(filled_index, cnt - 1);
 191
 192         for (i = 0; i < cnt; i++)
 193                 repo_parse_commit(r, array[i]);
 194         for (i = 0; i < cnt; i++) {
 195                 struct commit_list *common;
 196                 timestamp_t min_generation = commit_graph_generation(array[i]);
 197
 198                 if (redundant[i])
 199                         continue;
 200                 for (j = filled = 0; j < cnt; j++) {
 201                         timestamp_t curr_generation;
 202                         if (i == j || redundant[j])
 203                                 continue;
 204                         filled_index[filled] = j;
 205                         work[filled++] = array[j];
 206
 207                         curr_generation = commit_graph_generation(array[j]);
 208                         if (curr_generation < min_generation)
 209                                 min_generation = curr_generation;
 210                 }
 211                 common = paint_down_to_common(r, array[i], filled,
 212                                               work, min_generation);
 213                 if (array[i]->object.flags & PARENT2)
 214                         redundant[i] = 1;
 215                 for (j = 0; j < filled; j++)
 216                         if (work[j]->object.flags & PARENT1)
 217                                 redundant[filled_index[j]] = 1;
 218                 clear_commit_marks(array[i], all_flags);
 219                 clear_commit_marks_many(filled, work, all_flags);
 220                 free_commit_list(common);
 221         }
 222
 223         /* Now collect the result */
 224         COPY_ARRAY(work, array, cnt);
 225         for (i = filled = 0; i < cnt; i++)
 226                 if (!redundant[i])
 227                         array[filled++] = work[i];
 228         free(work);
 229         free(redundant);
 230         free(filled_index);
 231         return filled;
 232 }
 233
 234 static int remove_redundant_with_gen(struct repository *r,
 235                                      struct commit **array, int cnt)
 236 {
 237         int i, count_non_stale = 0, count_still_independent = cnt;
 238         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
 239         struct commit **walk_start, **sorted;
 240         size_t walk_start_nr = 0, walk_start_alloc = cnt;
 241         int min_gen_pos = 0;
 242
 243         /*
 244          * Sort the input by generation number, ascending. This allows
 245          * us to increase the "min_generation" limit when we discover
 246          * the commit with lowest generation is STALE. The index
 247          * min_gen_pos points to the current position within 'array'
 248          * that is not yet known to be STALE.
 249          */
 250         DUP_ARRAY(sorted, array, cnt);
 251         QSORT(sorted, cnt, compare_commits_by_gen);
 252         min_generation = commit_graph_generation(sorted[0]);
 253
 254         ALLOC_ARRAY(walk_start, walk_start_alloc);
 255
 256         /* Mark all parents of the input as STALE */
 257         for (i = 0; i < cnt; i++) {
 258                 struct commit_list *parents;
 259
 260                 repo_parse_commit(r, array[i]);
 261                 array[i]->object.flags |= RESULT;
 262                 parents = array[i]->parents;
 263
 264                 while (parents) {
 265                         repo_parse_commit(r, parents->item);
 266                         if (!(parents->item->object.flags & STALE)) {
 267                                 parents->item->object.flags |= STALE;
 268                                 ALLOC_GROW(walk_start, walk_start_nr + 1, walk_start_alloc);
 269                                 walk_start[walk_start_nr++] = parents->item;
 270                         }
 271                         parents = parents->next;
 272                 }
 273         }
 274
 275         QSORT(walk_start, walk_start_nr, compare_commits_by_gen);
 276
 277         /* remove STALE bit for now to allow walking through parents */
 278         for (i = 0; i < walk_start_nr; i++)
 279                 walk_start[i]->object.flags &= ~STALE;
 280
 281         /*
 282          * Start walking from the highest generation. Hopefully, it will
 283          * find all other items during the first-parent walk, and we can
 284          * terminate early. Otherwise, we will do the same amount of work
 285          * as before.
 286          */
 287         for (i = walk_start_nr - 1; i >= 0 && count_still_independent > 1; i--) {
 288                 /* push the STALE bits up to min generation */
 289                 struct commit_list *stack = NULL;
 290
 291                 commit_list_insert(walk_start[i], &stack);
 292                 walk_start[i]->object.flags |= STALE;
 293
 294                 while (stack) {
 295                         struct commit_list *parents;
 296                         struct commit *c = stack->item;
 297
 298                         repo_parse_commit(r, c);
 299
 300                         if (c->object.flags & RESULT) {
 301                                 c->object.flags &= ~RESULT;
 302                                 if (--count_still_independent <= 1)
 303                                         break;
 304                                 if (oideq(&c->object.oid, &sorted[min_gen_pos]->object.oid)) {
 305                                         while (min_gen_pos < cnt - 1 &&
 306                                                (sorted[min_gen_pos]->object.flags & STALE))
 307                                                 min_gen_pos++;
 308                                         min_generation = commit_graph_generation(sorted[min_gen_pos]);
 309                                 }
 310                         }
 311
 312                         if (commit_graph_generation(c) < min_generation) {
 313                                 pop_commit(&stack);
 314                                 continue;
 315                         }
 316
 317                         parents = c->parents;
 318                         while (parents) {
 319                                 if (!(parents->item->object.flags & STALE)) {
 320                                         parents->item->object.flags |= STALE;
 321                                         commit_list_insert(parents->item, &stack);
 322                                         break;
 323                                 }
 324                                 parents = parents->next;
 325                         }
 326
 327                         /* pop if all parents have been visited already */
 328                         if (!parents)
 329                                 pop_commit(&stack);
 330                 }
 331                 free_commit_list(stack);
 332         }
 333         free(sorted);
 334
 335         /* clear result */
 336         for (i = 0; i < cnt; i++)
 337                 array[i]->object.flags &= ~RESULT;
 338
 339         /* rearrange array */
 340         for (i = count_non_stale = 0; i < cnt; i++) {
 341                 if (!(array[i]->object.flags & STALE))
 342                         array[count_non_stale++] = array[i];
 343         }
 344
 345         /* clear marks */
 346         clear_commit_marks_many(walk_start_nr, walk_start, STALE);
 347         free(walk_start);
 348
 349         return count_non_stale;
 350 }
 351
 352 static int remove_redundant(struct repository *r, struct commit **array, int cnt)
 353 {
 354         /*
 355          * Some commit in the array may be an ancestor of
 356          * another commit.  Move the independent commits to the
 357          * beginning of 'array' and return their number. Callers
 358          * should not rely upon the contents of 'array' after
 359          * that number.
 360          */
 361         if (generation_numbers_enabled(r)) {
 362                 int i;
 363
 364                 /*
 365                  * If we have a single commit with finite generation
 366                  * number, then the _with_gen algorithm is preferred.
 367                  */
 368                 for (i = 0; i < cnt; i++) {
 369                         if (commit_graph_generation(array[i]) < GENERATION_NUMBER_INFINITY)
 370                                 return remove_redundant_with_gen(r, array, cnt);
 371                 }
 372         }
 373
 374         return remove_redundant_no_gen(r, array, cnt);
 375 }
 376
 377 static struct commit_list *get_merge_bases_many_0(struct repository *r,
 378                                                   struct commit *one,
 379                                                   int n,
 380                                                   struct commit **twos,
 381                                                   int cleanup)
 382 {
 383         struct commit_list *list;
 384         struct commit **rslt;
 385         struct commit_list *result;
 386         int cnt, i;
 387
 388         result = merge_bases_many(r, one, n, twos);
 389         for (i = 0; i < n; i++) {
 390                 if (one == twos[i])
 391                         return result;
 392         }
 393         if (!result || !result->next) {
 394                 if (cleanup) {
 395                         clear_commit_marks(one, all_flags);
 396                         clear_commit_marks_many(n, twos, all_flags);
 397                 }
 398                 return result;
 399         }
 400
 401         /* There are more than one */
 402         cnt = commit_list_count(result);
 403         CALLOC_ARRAY(rslt, cnt);
 404         for (list = result, i = 0; list; list = list->next)
 405                 rslt[i++] = list->item;
 406         free_commit_list(result);
 407
 408         clear_commit_marks(one, all_flags);
 409         clear_commit_marks_many(n, twos, all_flags);
 410
 411         cnt = remove_redundant(r, rslt, cnt);
 412         result = NULL;
 413         for (i = 0; i < cnt; i++)
 414                 commit_list_insert_by_date(rslt[i], &result);
 415         free(rslt);
 416         return result;
 417 }
 418
 419 struct commit_list *repo_get_merge_bases_many(struct repository *r,
 420                                               struct commit *one,
 421                                               int n,
 422                                               struct commit **twos)
 423 {
 424         return get_merge_bases_many_0(r, one, n, twos, 1);
 425 }
 426
 427 struct commit_list *repo_get_merge_bases_many_dirty(struct repository *r,
 428                                                     struct commit *one,
 429                                                     int n,
 430                                                     struct commit **twos)
 431 {
 432         return get_merge_bases_many_0(r, one, n, twos, 0);
 433 }
 434
 435 struct commit_list *repo_get_merge_bases(struct repository *r,
 436                                          struct commit *one,
 437                                          struct commit *two)
 438 {
 439         return get_merge_bases_many_0(r, one, 1, &two, 1);
 440 }
 441
 442 /*
 443  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 444  */
 445 int repo_is_descendant_of(struct repository *r,
 446                           struct commit *commit,
 447                           struct commit_list *with_commit)
 448 {
 449         if (!with_commit)
 450                 return 1;
 451
 452         if (generation_numbers_enabled(the_repository)) {
 453                 struct commit_list *from_list = NULL;
 454                 int result;
 455                 commit_list_insert(commit, &from_list);
 456                 result = can_all_from_reach(from_list, with_commit, 0);
 457                 free_commit_list(from_list);
 458                 return result;
 459         } else {
 460                 while (with_commit) {
 461                         struct commit *other;
 462
 463                         other = with_commit->item;
 464                         with_commit = with_commit->next;
 465                         if (repo_in_merge_bases_many(r, other, 1, &commit))
 466                                 return 1;
 467                 }
 468                 return 0;
 469         }
 470 }
 471
 472 /*
 473  * Is "commit" an ancestor of one of the "references"?
 474  */
 475 int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
 476                              int nr_reference, struct commit **reference)
 477 {
 478         struct commit_list *bases;
 479         int ret = 0, i;
 480         timestamp_t generation, max_generation = GENERATION_NUMBER_ZERO;
 481
 482         if (repo_parse_commit(r, commit))
 483                 return ret;
 484         for (i = 0; i < nr_reference; i++) {
 485                 if (repo_parse_commit(r, reference[i]))
 486                         return ret;
 487
 488                 generation = commit_graph_generation(reference[i]);
 489                 if (generation > max_generation)
 490                         max_generation = generation;
 491         }
 492
 493         generation = commit_graph_generation(commit);
 494         if (generation > max_generation)
 495                 return ret;
 496
 497         bases = paint_down_to_common(r, commit,
 498                                      nr_reference, reference,
 499                                      generation);
 500         if (commit->object.flags & PARENT2)
 501                 ret = 1;
 502         clear_commit_marks(commit, all_flags);
 503         clear_commit_marks_many(nr_reference, reference, all_flags);
 504         free_commit_list(bases);
 505         return ret;
 506 }
 507
 508 /*
 509  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 510  */
 511 int repo_in_merge_bases(struct repository *r,
 512                         struct commit *commit,
 513                         struct commit *reference)
 514 {
 515         int res;
 516         struct commit_list *list = NULL;
 517         struct commit_list **next = &list;
 518
 519         next = commit_list_append(commit, next);
 520         res = repo_is_descendant_of(r, reference, list);
 521         free_commit_list(list);
 522
 523         return res;
 524 }
 525
 526 struct commit_list *reduce_heads(struct commit_list *heads)
 527 {
 528         struct commit_list *p;
 529         struct commit_list *result = NULL, **tail = &result;
 530         struct commit **array;
 531         int num_head, i;
 532
 533         if (!heads)
 534                 return NULL;
 535
 536         /* Uniquify */
 537         for (p = heads; p; p = p->next)
 538                 p->item->object.flags &= ~STALE;
 539         for (p = heads, num_head = 0; p; p = p->next) {
 540                 if (p->item->object.flags & STALE)
 541                         continue;
 542                 p->item->object.flags |= STALE;
 543                 num_head++;
 544         }
 545         CALLOC_ARRAY(array, num_head);
 546         for (p = heads, i = 0; p; p = p->next) {
 547                 if (p->item->object.flags & STALE) {
 548                         array[i++] = p->item;
 549                         p->item->object.flags &= ~STALE;
 550                 }
 551         }
 552         num_head = remove_redundant(the_repository, array, num_head);
 553         for (i = 0; i < num_head; i++)
 554                 tail = &commit_list_insert(array[i], tail)->next;
 555         free(array);
 556         return result;
 557 }
 558
 559 void reduce_heads_replace(struct commit_list **heads)
 560 {
 561         struct commit_list *result = reduce_heads(*heads);
 562         free_commit_list(*heads);
 563         *heads = result;
 564 }
 565
 566 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 567 {
 568         struct object *o;
 569         struct commit *old_commit, *new_commit;
 570         struct commit_list *old_commit_list = NULL;
 571         int ret;
 572
 573         /*
 574          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
 575          * old_commit.  Otherwise we require --force.
 576          */
 577         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
 578                       NULL, 0);
 579         if (!o || o->type != OBJ_COMMIT)
 580                 return 0;
 581         old_commit = (struct commit *) o;
 582
 583         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
 584                       NULL, 0);
 585         if (!o || o->type != OBJ_COMMIT)
 586                 return 0;
 587         new_commit = (struct commit *) o;
 588
 589         if (parse_commit(new_commit) < 0)
 590                 return 0;
 591
 592         commit_list_insert(old_commit, &old_commit_list);
 593         ret = repo_is_descendant_of(the_repository,
 594                                     new_commit, old_commit_list);
 595         free_commit_list(old_commit_list);
 596         return ret;
 597 }
 598
 599 /*
 600  * Mimicking the real stack, this stack lives on the heap, avoiding stack
 601  * overflows.
 602  *
 603  * At each recursion step, the stack items points to the commits whose
 604  * ancestors are to be inspected.
 605  */
 606 struct contains_stack {
 607         int nr, alloc;
 608         struct contains_stack_entry {
 609                 struct commit *commit;
 610                 struct commit_list *parents;
 611         } *contains_stack;
 612 };
 613
 614 static int in_commit_list(const struct commit_list *want, struct commit *c)
 615 {
 616         for (; want; want = want->next)
 617                 if (oideq(&want->item->object.oid, &c->object.oid))
 618                         return 1;
 619         return 0;
 620 }
 621
 622 /*
 623  * Test whether the candidate is contained in the list.
 624  * Do not recurse to find out, though, but return -1 if inconclusive.
 625  */
 626 static enum contains_result contains_test(struct commit *candidate,
 627                                           const struct commit_list *want,
 628                                           struct contains_cache *cache,
 629                                           timestamp_t cutoff)
 630 {
 631         enum contains_result *cached = contains_cache_at(cache, candidate);
 632
 633         /* If we already have the answer cached, return that. */
 634         if (*cached)
 635                 return *cached;
 636
 637         /* or are we it? */
 638         if (in_commit_list(want, candidate)) {
 639                 *cached = CONTAINS_YES;
 640                 return CONTAINS_YES;
 641         }
 642
 643         /* Otherwise, we don't know; prepare to recurse */
 644         parse_commit_or_die(candidate);
 645
 646         if (commit_graph_generation(candidate) < cutoff)
 647                 return CONTAINS_NO;
 648
 649         return CONTAINS_UNKNOWN;
 650 }
 651
 652 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
 653 {
 654         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
 655         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
 656         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
 657 }
 658
 659 static enum contains_result contains_tag_algo(struct commit *candidate,
 660                                               const struct commit_list *want,
 661                                               struct contains_cache *cache)
 662 {
 663         struct contains_stack contains_stack = { 0, 0, NULL };
 664         enum contains_result result;
 665         timestamp_t cutoff = GENERATION_NUMBER_INFINITY;
 666         const struct commit_list *p;
 667
 668         for (p = want; p; p = p->next) {
 669                 timestamp_t generation;
 670                 struct commit *c = p->item;
 671                 load_commit_graph_info(the_repository, c);
 672                 generation = commit_graph_generation(c);
 673                 if (generation < cutoff)
 674                         cutoff = generation;
 675         }
 676
 677         result = contains_test(candidate, want, cache, cutoff);
 678         if (result != CONTAINS_UNKNOWN)
 679                 return result;
 680
 681         push_to_contains_stack(candidate, &contains_stack);
 682         while (contains_stack.nr) {
 683                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
 684                 struct commit *commit = entry->commit;
 685                 struct commit_list *parents = entry->parents;
 686
 687                 if (!parents) {
 688                         *contains_cache_at(cache, commit) = CONTAINS_NO;
 689                         contains_stack.nr--;
 690                 }
 691                 /*
 692                  * If we just popped the stack, parents->item has been marked,
 693                  * therefore contains_test will return a meaningful yes/no.
 694                  */
 695                 else switch (contains_test(parents->item, want, cache, cutoff)) {
 696                 case CONTAINS_YES:
 697                         *contains_cache_at(cache, commit) = CONTAINS_YES;
 698                         contains_stack.nr--;
 699                         break;
 700                 case CONTAINS_NO:
 701                         entry->parents = parents->next;
 702                         break;
 703                 case CONTAINS_UNKNOWN:
 704                         push_to_contains_stack(parents->item, &contains_stack);
 705                         break;
 706                 }
 707         }
 708         free(contains_stack.contains_stack);
 709         return contains_test(candidate, want, cache, cutoff);
 710 }
 711
 712 int commit_contains(struct ref_filter *filter, struct commit *commit,
 713                     struct commit_list *list, struct contains_cache *cache)
 714 {
 715         if (filter->with_commit_tag_algo)
 716                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
 717         return repo_is_descendant_of(the_repository, commit, list);
 718 }
 719
 720 int can_all_from_reach_with_flag(struct object_array *from,
 721                                  unsigned int with_flag,
 722                                  unsigned int assign_flag,
 723                                  time_t min_commit_date,
 724                                  timestamp_t min_generation)
 725 {
 726         struct commit **list = NULL;
 727         int i;
 728         int nr_commits;
 729         int result = 1;
 730
 731         ALLOC_ARRAY(list, from->nr);
 732         nr_commits = 0;
 733         for (i = 0; i < from->nr; i++) {
 734                 struct object *from_one = from->objects[i].item;
 735
 736                 if (!from_one || from_one->flags & assign_flag)
 737                         continue;
 738
 739                 from_one = deref_tag(the_repository, from_one,
 740                                      "a from object", 0);
 741                 if (!from_one || from_one->type != OBJ_COMMIT) {
 742                         /*
 743                          * no way to tell if this is reachable by
 744                          * looking at the ancestry chain alone, so
 745                          * leave a note to ourselves not to worry about
 746                          * this object anymore.
 747                          */
 748                         from->objects[i].item->flags |= assign_flag;
 749                         continue;
 750                 }
 751
 752                 list[nr_commits] = (struct commit *)from_one;
 753                 if (parse_commit(list[nr_commits]) ||
 754                     commit_graph_generation(list[nr_commits]) < min_generation) {
 755                         result = 0;
 756                         goto cleanup;
 757                 }
 758
 759                 nr_commits++;
 760         }
 761
 762         QSORT(list, nr_commits, compare_commits_by_gen);
 763
 764         for (i = 0; i < nr_commits; i++) {
 765                 /* DFS from list[i] */
 766                 struct commit_list *stack = NULL;
 767
 768                 list[i]->object.flags |= assign_flag;
 769                 commit_list_insert(list[i], &stack);
 770
 771                 while (stack) {
 772                         struct commit_list *parent;
 773
 774                         if (stack->item->object.flags & (with_flag | RESULT)) {
 775                                 pop_commit(&stack);
 776                                 if (stack)
 777                                         stack->item->object.flags |= RESULT;
 778                                 continue;
 779                         }
 780
 781                         for (parent = stack->item->parents; parent; parent = parent->next) {
 782                                 if (parent->item->object.flags & (with_flag | RESULT))
 783                                         stack->item->object.flags |= RESULT;
 784
 785                                 if (!(parent->item->object.flags & assign_flag)) {
 786                                         parent->item->object.flags |= assign_flag;
 787
 788                                         if (parse_commit(parent->item) ||
 789                                             parent->item->date < min_commit_date ||
 790                                             commit_graph_generation(parent->item) < min_generation)
 791                                                 continue;
 792
 793                                         commit_list_insert(parent->item, &stack);
 794                                         break;
 795                                 }
 796                         }
 797
 798                         if (!parent)
 799                                 pop_commit(&stack);
 800                 }
 801
 802                 if (!(list[i]->object.flags & (with_flag | RESULT))) {
 803                         result = 0;
 804                         goto cleanup;
 805                 }
 806         }
 807
 808 cleanup:
 809         clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
 810         free(list);
 811
 812         for (i = 0; i < from->nr; i++)
 813                 from->objects[i].item->flags &= ~assign_flag;
 814
 815         return result;
 816 }
 817
 818 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 819                        int cutoff_by_min_date)
 820 {
 821         struct object_array from_objs = OBJECT_ARRAY_INIT;
 822         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
 823         struct commit_list *from_iter = from, *to_iter = to;
 824         int result;
 825         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
 826
 827         while (from_iter) {
 828                 add_object_array(&from_iter->item->object, NULL, &from_objs);
 829
 830                 if (!parse_commit(from_iter->item)) {
 831                         timestamp_t generation;
 832                         if (from_iter->item->date < min_commit_date)
 833                                 min_commit_date = from_iter->item->date;
 834
 835                         generation = commit_graph_generation(from_iter->item);
 836                         if (generation < min_generation)
 837                                 min_generation = generation;
 838                 }
 839
 840                 from_iter = from_iter->next;
 841         }
 842
 843         while (to_iter) {
 844                 if (!parse_commit(to_iter->item)) {
 845                         timestamp_t generation;
 846                         if (to_iter->item->date < min_commit_date)
 847                                 min_commit_date = to_iter->item->date;
 848
 849                         generation = commit_graph_generation(to_iter->item);
 850                         if (generation < min_generation)
 851                                 min_generation = generation;
 852                 }
 853
 854                 to_iter->item->object.flags |= PARENT2;
 855
 856                 to_iter = to_iter->next;
 857         }
 858
 859         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
 860                                               min_commit_date, min_generation);
 861
 862         while (from) {
 863                 clear_commit_marks(from->item, PARENT1);
 864                 from = from->next;
 865         }
 866
 867         while (to) {
 868                 clear_commit_marks(to->item, PARENT2);
 869                 to = to->next;
 870         }
 871
 872         object_array_clear(&from_objs);
 873         return result;
 874 }
 875
 876 struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
 877                                          struct commit **to, int nr_to,
 878                                          unsigned int reachable_flag)
 879 {
 880         struct commit **item;
 881         struct commit *current;
 882         struct commit_list *found_commits = NULL;
 883         struct commit **to_last = to + nr_to;
 884         struct commit **from_last = from + nr_from;
 885         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
 886         int num_to_find = 0;
 887
 888         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
 889
 890         for (item = to; item < to_last; item++) {
 891                 timestamp_t generation;
 892                 struct commit *c = *item;
 893
 894                 parse_commit(c);
 895                 generation = commit_graph_generation(c);
 896                 if (generation < min_generation)
 897                         min_generation = generation;
 898
 899                 if (!(c->object.flags & PARENT1)) {
 900                         c->object.flags |= PARENT1;
 901                         num_to_find++;
 902                 }
 903         }
 904
 905         for (item = from; item < from_last; item++) {
 906                 struct commit *c = *item;
 907                 if (!(c->object.flags & PARENT2)) {
 908                         c->object.flags |= PARENT2;
 909                         parse_commit(c);
 910
 911                         prio_queue_put(&queue, *item);
 912                 }
 913         }
 914
 915         while (num_to_find && (current = prio_queue_get(&queue)) != NULL) {
 916                 struct commit_list *parents;
 917
 918                 if (current->object.flags & PARENT1) {
 919                         current->object.flags &= ~PARENT1;
 920                         current->object.flags |= reachable_flag;
 921                         commit_list_insert(current, &found_commits);
 922                         num_to_find--;
 923                 }
 924
 925                 for (parents = current->parents; parents; parents = parents->next) {
 926                         struct commit *p = parents->item;
 927
 928                         parse_commit(p);
 929
 930                         if (commit_graph_generation(p) < min_generation)
 931                                 continue;
 932
 933                         if (p->object.flags & PARENT2)
 934                                 continue;
 935
 936                         p->object.flags |= PARENT2;
 937                         prio_queue_put(&queue, p);
 938                 }
 939         }
 940
 941         clear_commit_marks_many(nr_to, to, PARENT1);
 942         clear_commit_marks_many(nr_from, from, PARENT2);
 943
 944         return found_commits;
 945 }