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 REACHABLE       (1u<<15)
  14 #define PARENT1         (1u<<16)
  15 #define PARENT2         (1u<<17)
  16 #define STALE           (1u<<18)
  17 #define RESULT          (1u<<19)
  18
  19 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
  20
  21 static int queue_has_nonstale(struct prio_queue *queue)
  22 {
  23         int i;
  24         for (i = 0; i < queue->nr; i++) {
  25                 struct commit *commit = queue->array[i].data;
  26                 if (!(commit->object.flags & STALE))
  27                         return 1;
  28         }
  29         return 0;
  30 }
  31
  32 /* all input commits in one and twos[] must have been parsed! */
  33 static struct commit_list *paint_down_to_common(struct repository *r,
  34                                                 struct commit *one, int n,
  35                                                 struct commit **twos,
  36                                                 int min_generation)
  37 {
  38         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
  39         struct commit_list *result = NULL;
  40         int i;
  41         uint32_t last_gen = GENERATION_NUMBER_INFINITY;
  42
  43         if (!min_generation)
  44                 queue.compare = compare_commits_by_commit_date;
  45
  46         one->object.flags |= PARENT1;
  47         if (!n) {
  48                 commit_list_append(one, &result);
  49                 return result;
  50         }
  51         prio_queue_put(&queue, one);
  52
  53         for (i = 0; i < n; i++) {
  54                 twos[i]->object.flags |= PARENT2;
  55                 prio_queue_put(&queue, twos[i]);
  56         }
  57
  58         while (queue_has_nonstale(&queue)) {
  59                 struct commit *commit = prio_queue_get(&queue);
  60                 struct commit_list *parents;
  61                 int flags;
  62
  63                 if (min_generation && commit->generation > last_gen)
  64                         BUG("bad generation skip %8x > %8x at %s",
  65                             commit->generation, last_gen,
  66                             oid_to_hex(&commit->object.oid));
  67                 last_gen = commit->generation;
  68
  69                 if (commit->generation < min_generation)
  70                         break;
  71
  72                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
  73                 if (flags == (PARENT1 | PARENT2)) {
  74                         if (!(commit->object.flags & RESULT)) {
  75                                 commit->object.flags |= RESULT;
  76                                 commit_list_insert_by_date(commit, &result);
  77                         }
  78                         /* Mark parents of a found merge stale */
  79                         flags |= STALE;
  80                 }
  81                 parents = commit->parents;
  82                 while (parents) {
  83                         struct commit *p = parents->item;
  84                         parents = parents->next;
  85                         if ((p->object.flags & flags) == flags)
  86                                 continue;
  87                         if (repo_parse_commit(r, p))
  88                                 return NULL;
  89                         p->object.flags |= flags;
  90                         prio_queue_put(&queue, p);
  91                 }
  92         }
  93
  94         clear_prio_queue(&queue);
  95         return result;
  96 }
  97
  98 static struct commit_list *merge_bases_many(struct repository *r,
  99                                             struct commit *one, int n,
 100                                             struct commit **twos)
 101 {
 102         struct commit_list *list = NULL;
 103         struct commit_list *result = NULL;
 104         int i;
 105
 106         for (i = 0; i < n; i++) {
 107                 if (one == twos[i])
 108                         /*
 109                          * We do not mark this even with RESULT so we do not
 110                          * have to clean it up.
 111                          */
 112                         return commit_list_insert(one, &result);
 113         }
 114
 115         if (repo_parse_commit(r, one))
 116                 return NULL;
 117         for (i = 0; i < n; i++) {
 118                 if (repo_parse_commit(r, twos[i]))
 119                         return NULL;
 120         }
 121
 122         list = paint_down_to_common(r, one, n, twos, 0);
 123
 124         while (list) {
 125                 struct commit *commit = pop_commit(&list);
 126                 if (!(commit->object.flags & STALE))
 127                         commit_list_insert_by_date(commit, &result);
 128         }
 129         return result;
 130 }
 131
 132 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 133 {
 134         struct commit_list *i, *j, *k, *ret = NULL;
 135
 136         if (!in)
 137                 return ret;
 138
 139         commit_list_insert(in->item, &ret);
 140
 141         for (i = in->next; i; i = i->next) {
 142                 struct commit_list *new_commits = NULL, *end = NULL;
 143
 144                 for (j = ret; j; j = j->next) {
 145                         struct commit_list *bases;
 146                         bases = get_merge_bases(i->item, j->item);
 147                         if (!new_commits)
 148                                 new_commits = bases;
 149                         else
 150                                 end->next = bases;
 151                         for (k = bases; k; k = k->next)
 152                                 end = k;
 153                 }
 154                 ret = new_commits;
 155         }
 156         return ret;
 157 }
 158
 159 static int remove_redundant(struct repository *r, struct commit **array, int cnt)
 160 {
 161         /*
 162          * Some commit in the array may be an ancestor of
 163          * another commit.  Move such commit to the end of
 164          * the array, and return the number of commits that
 165          * are independent from each other.
 166          */
 167         struct commit **work;
 168         unsigned char *redundant;
 169         int *filled_index;
 170         int i, j, filled;
 171
 172         work = xcalloc(cnt, sizeof(*work));
 173         redundant = xcalloc(cnt, 1);
 174         ALLOC_ARRAY(filled_index, cnt - 1);
 175
 176         for (i = 0; i < cnt; i++)
 177                 repo_parse_commit(r, array[i]);
 178         for (i = 0; i < cnt; i++) {
 179                 struct commit_list *common;
 180                 uint32_t min_generation = array[i]->generation;
 181
 182                 if (redundant[i])
 183                         continue;
 184                 for (j = filled = 0; j < cnt; j++) {
 185                         if (i == j || redundant[j])
 186                                 continue;
 187                         filled_index[filled] = j;
 188                         work[filled++] = array[j];
 189
 190                         if (array[j]->generation < min_generation)
 191                                 min_generation = array[j]->generation;
 192                 }
 193                 common = paint_down_to_common(r, array[i], filled,
 194                                               work, min_generation);
 195                 if (array[i]->object.flags & PARENT2)
 196                         redundant[i] = 1;
 197                 for (j = 0; j < filled; j++)
 198                         if (work[j]->object.flags & PARENT1)
 199                                 redundant[filled_index[j]] = 1;
 200                 clear_commit_marks(array[i], all_flags);
 201                 clear_commit_marks_many(filled, work, all_flags);
 202                 free_commit_list(common);
 203         }
 204
 205         /* Now collect the result */
 206         COPY_ARRAY(work, array, cnt);
 207         for (i = filled = 0; i < cnt; i++)
 208                 if (!redundant[i])
 209                         array[filled++] = work[i];
 210         for (j = filled, i = 0; i < cnt; i++)
 211                 if (redundant[i])
 212                         array[j++] = work[i];
 213         free(work);
 214         free(redundant);
 215         free(filled_index);
 216         return filled;
 217 }
 218
 219 static struct commit_list *get_merge_bases_many_0(struct repository *r,
 220                                                   struct commit *one,
 221                                                   int n,
 222                                                   struct commit **twos,
 223                                                   int cleanup)
 224 {
 225         struct commit_list *list;
 226         struct commit **rslt;
 227         struct commit_list *result;
 228         int cnt, i;
 229
 230         result = merge_bases_many(r, one, n, twos);
 231         for (i = 0; i < n; i++) {
 232                 if (one == twos[i])
 233                         return result;
 234         }
 235         if (!result || !result->next) {
 236                 if (cleanup) {
 237                         clear_commit_marks(one, all_flags);
 238                         clear_commit_marks_many(n, twos, all_flags);
 239                 }
 240                 return result;
 241         }
 242
 243         /* There are more than one */
 244         cnt = commit_list_count(result);
 245         rslt = xcalloc(cnt, sizeof(*rslt));
 246         for (list = result, i = 0; list; list = list->next)
 247                 rslt[i++] = list->item;
 248         free_commit_list(result);
 249
 250         clear_commit_marks(one, all_flags);
 251         clear_commit_marks_many(n, twos, all_flags);
 252
 253         cnt = remove_redundant(r, rslt, cnt);
 254         result = NULL;
 255         for (i = 0; i < cnt; i++)
 256                 commit_list_insert_by_date(rslt[i], &result);
 257         free(rslt);
 258         return result;
 259 }
 260
 261 struct commit_list *get_merge_bases_many(struct commit *one,
 262                                          int n,
 263                                          struct commit **twos)
 264 {
 265         return get_merge_bases_many_0(the_repository, one, n, twos, 1);
 266 }
 267
 268 struct commit_list *get_merge_bases_many_dirty(struct commit *one,
 269                                                int n,
 270                                                struct commit **twos)
 271 {
 272         return get_merge_bases_many_0(the_repository, one, n, twos, 0);
 273 }
 274
 275 struct commit_list *get_merge_bases(struct commit *one, struct commit *two)
 276 {
 277         return get_merge_bases_many_0(the_repository, one, 1, &two, 1);
 278 }
 279
 280 /*
 281  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 282  */
 283 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 284 {
 285         if (!with_commit)
 286                 return 1;
 287
 288         if (generation_numbers_enabled(the_repository)) {
 289                 struct commit_list *from_list = NULL;
 290                 int result;
 291                 commit_list_insert(commit, &from_list);
 292                 result = can_all_from_reach(from_list, with_commit, 0);
 293                 free_commit_list(from_list);
 294                 return result;
 295         } else {
 296                 while (with_commit) {
 297                         struct commit *other;
 298
 299                         other = with_commit->item;
 300                         with_commit = with_commit->next;
 301                         if (in_merge_bases(other, commit))
 302                                 return 1;
 303                 }
 304                 return 0;
 305         }
 306 }
 307
 308 /*
 309  * Is "commit" an ancestor of one of the "references"?
 310  */
 311 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 312 {
 313         struct commit_list *bases;
 314         int ret = 0, i;
 315         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
 316
 317         if (parse_commit(commit))
 318                 return ret;
 319         for (i = 0; i < nr_reference; i++) {
 320                 if (parse_commit(reference[i]))
 321                         return ret;
 322                 if (reference[i]->generation < min_generation)
 323                         min_generation = reference[i]->generation;
 324         }
 325
 326         if (commit->generation > min_generation)
 327                 return ret;
 328
 329         bases = paint_down_to_common(the_repository, commit,
 330                                      nr_reference, reference,
 331                                      commit->generation);
 332         if (commit->object.flags & PARENT2)
 333                 ret = 1;
 334         clear_commit_marks(commit, all_flags);
 335         clear_commit_marks_many(nr_reference, reference, all_flags);
 336         free_commit_list(bases);
 337         return ret;
 338 }
 339
 340 /*
 341  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 342  */
 343 int in_merge_bases(struct commit *commit, struct commit *reference)
 344 {
 345         return in_merge_bases_many(commit, 1, &reference);
 346 }
 347
 348 struct commit_list *reduce_heads(struct commit_list *heads)
 349 {
 350         struct commit_list *p;
 351         struct commit_list *result = NULL, **tail = &result;
 352         struct commit **array;
 353         int num_head, i;
 354
 355         if (!heads)
 356                 return NULL;
 357
 358         /* Uniquify */
 359         for (p = heads; p; p = p->next)
 360                 p->item->object.flags &= ~STALE;
 361         for (p = heads, num_head = 0; p; p = p->next) {
 362                 if (p->item->object.flags & STALE)
 363                         continue;
 364                 p->item->object.flags |= STALE;
 365                 num_head++;
 366         }
 367         array = xcalloc(num_head, sizeof(*array));
 368         for (p = heads, i = 0; p; p = p->next) {
 369                 if (p->item->object.flags & STALE) {
 370                         array[i++] = p->item;
 371                         p->item->object.flags &= ~STALE;
 372                 }
 373         }
 374         num_head = remove_redundant(the_repository, array, num_head);
 375         for (i = 0; i < num_head; i++)
 376                 tail = &commit_list_insert(array[i], tail)->next;
 377         free(array);
 378         return result;
 379 }
 380
 381 void reduce_heads_replace(struct commit_list **heads)
 382 {
 383         struct commit_list *result = reduce_heads(*heads);
 384         free_commit_list(*heads);
 385         *heads = result;
 386 }
 387
 388 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 389 {
 390         struct object *o;
 391         struct commit *old_commit, *new_commit;
 392         struct commit_list *old_commit_list = NULL;
 393
 394         /*
 395          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
 396          * old_commit.  Otherwise we require --force.
 397          */
 398         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
 399                       NULL, 0);
 400         if (!o || o->type != OBJ_COMMIT)
 401                 return 0;
 402         old_commit = (struct commit *) o;
 403
 404         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
 405                       NULL, 0);
 406         if (!o || o->type != OBJ_COMMIT)
 407                 return 0;
 408         new_commit = (struct commit *) o;
 409
 410         if (parse_commit(new_commit) < 0)
 411                 return 0;
 412
 413         commit_list_insert(old_commit, &old_commit_list);
 414         return is_descendant_of(new_commit, old_commit_list);
 415 }
 416
 417 /*
 418  * Mimicking the real stack, this stack lives on the heap, avoiding stack
 419  * overflows.
 420  *
 421  * At each recursion step, the stack items points to the commits whose
 422  * ancestors are to be inspected.
 423  */
 424 struct contains_stack {
 425         int nr, alloc;
 426         struct contains_stack_entry {
 427                 struct commit *commit;
 428                 struct commit_list *parents;
 429         } *contains_stack;
 430 };
 431
 432 static int in_commit_list(const struct commit_list *want, struct commit *c)
 433 {
 434         for (; want; want = want->next)
 435                 if (oideq(&want->item->object.oid, &c->object.oid))
 436                         return 1;
 437         return 0;
 438 }
 439
 440 /*
 441  * Test whether the candidate is contained in the list.
 442  * Do not recurse to find out, though, but return -1 if inconclusive.
 443  */
 444 static enum contains_result contains_test(struct commit *candidate,
 445                                           const struct commit_list *want,
 446                                           struct contains_cache *cache,
 447                                           uint32_t cutoff)
 448 {
 449         enum contains_result *cached = contains_cache_at(cache, candidate);
 450
 451         /* If we already have the answer cached, return that. */
 452         if (*cached)
 453                 return *cached;
 454
 455         /* or are we it? */
 456         if (in_commit_list(want, candidate)) {
 457                 *cached = CONTAINS_YES;
 458                 return CONTAINS_YES;
 459         }
 460
 461         /* Otherwise, we don't know; prepare to recurse */
 462         parse_commit_or_die(candidate);
 463
 464         if (candidate->generation < cutoff)
 465                 return CONTAINS_NO;
 466
 467         return CONTAINS_UNKNOWN;
 468 }
 469
 470 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
 471 {
 472         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
 473         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
 474         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
 475 }
 476
 477 static enum contains_result contains_tag_algo(struct commit *candidate,
 478                                               const struct commit_list *want,
 479                                               struct contains_cache *cache)
 480 {
 481         struct contains_stack contains_stack = { 0, 0, NULL };
 482         enum contains_result result;
 483         uint32_t cutoff = GENERATION_NUMBER_INFINITY;
 484         const struct commit_list *p;
 485
 486         for (p = want; p; p = p->next) {
 487                 struct commit *c = p->item;
 488                 load_commit_graph_info(the_repository, c);
 489                 if (c->generation < cutoff)
 490                         cutoff = c->generation;
 491         }
 492
 493         result = contains_test(candidate, want, cache, cutoff);
 494         if (result != CONTAINS_UNKNOWN)
 495                 return result;
 496
 497         push_to_contains_stack(candidate, &contains_stack);
 498         while (contains_stack.nr) {
 499                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
 500                 struct commit *commit = entry->commit;
 501                 struct commit_list *parents = entry->parents;
 502
 503                 if (!parents) {
 504                         *contains_cache_at(cache, commit) = CONTAINS_NO;
 505                         contains_stack.nr--;
 506                 }
 507                 /*
 508                  * If we just popped the stack, parents->item has been marked,
 509                  * therefore contains_test will return a meaningful yes/no.
 510                  */
 511                 else switch (contains_test(parents->item, want, cache, cutoff)) {
 512                 case CONTAINS_YES:
 513                         *contains_cache_at(cache, commit) = CONTAINS_YES;
 514                         contains_stack.nr--;
 515                         break;
 516                 case CONTAINS_NO:
 517                         entry->parents = parents->next;
 518                         break;
 519                 case CONTAINS_UNKNOWN:
 520                         push_to_contains_stack(parents->item, &contains_stack);
 521                         break;
 522                 }
 523         }
 524         free(contains_stack.contains_stack);
 525         return contains_test(candidate, want, cache, cutoff);
 526 }
 527
 528 int commit_contains(struct ref_filter *filter, struct commit *commit,
 529                     struct commit_list *list, struct contains_cache *cache)
 530 {
 531         if (filter->with_commit_tag_algo)
 532                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
 533         return is_descendant_of(commit, list);
 534 }
 535
 536 static int compare_commits_by_gen(const void *_a, const void *_b)
 537 {
 538         const struct commit *a = (const struct commit *)_a;
 539         const struct commit *b = (const struct commit *)_b;
 540
 541         if (a->generation < b->generation)
 542                 return -1;
 543         if (a->generation > b->generation)
 544                 return 1;
 545         return 0;
 546 }
 547
 548 int can_all_from_reach_with_flag(struct object_array *from,
 549                                  unsigned int with_flag,
 550                                  unsigned int assign_flag,
 551                                  time_t min_commit_date,
 552                                  uint32_t min_generation)
 553 {
 554         struct commit **list = NULL;
 555         int i;
 556         int nr_commits;
 557         int result = 1;
 558
 559         ALLOC_ARRAY(list, from->nr);
 560         nr_commits = 0;
 561         for (i = 0; i < from->nr; i++) {
 562                 struct object *from_one = from->objects[i].item;
 563
 564                 if (!from_one || from_one->flags & assign_flag)
 565                         continue;
 566
 567                 from_one = deref_tag(the_repository, from_one,
 568                                      "a from object", 0);
 569                 if (!from_one || from_one->type != OBJ_COMMIT) {
 570                         /*
 571                          * no way to tell if this is reachable by
 572                          * looking at the ancestry chain alone, so
 573                          * leave a note to ourselves not to worry about
 574                          * this object anymore.
 575                          */
 576                         from->objects[i].item->flags |= assign_flag;
 577                         continue;
 578                 }
 579
 580                 list[nr_commits] = (struct commit *)from_one;
 581                 if (parse_commit(list[nr_commits]) ||
 582                     list[nr_commits]->generation < min_generation) {
 583                         result = 0;
 584                         goto cleanup;
 585                 }
 586
 587                 nr_commits++;
 588         }
 589
 590         QSORT(list, nr_commits, compare_commits_by_gen);
 591
 592         for (i = 0; i < nr_commits; i++) {
 593                 /* DFS from list[i] */
 594                 struct commit_list *stack = NULL;
 595
 596                 list[i]->object.flags |= assign_flag;
 597                 commit_list_insert(list[i], &stack);
 598
 599                 while (stack) {
 600                         struct commit_list *parent;
 601
 602                         if (stack->item->object.flags & with_flag) {
 603                                 pop_commit(&stack);
 604                                 continue;
 605                         }
 606
 607                         for (parent = stack->item->parents; parent; parent = parent->next) {
 608                                 if (parent->item->object.flags & (with_flag | RESULT))
 609                                         stack->item->object.flags |= RESULT;
 610
 611                                 if (!(parent->item->object.flags & assign_flag)) {
 612                                         parent->item->object.flags |= assign_flag;
 613
 614                                         if (parse_commit(parent->item) ||
 615                                             parent->item->date < min_commit_date ||
 616                                             parent->item->generation < min_generation)
 617                                                 continue;
 618
 619                                         commit_list_insert(parent->item, &stack);
 620                                         break;
 621                                 }
 622                         }
 623
 624                         if (!parent)
 625                                 pop_commit(&stack);
 626                 }
 627
 628                 if (!(list[i]->object.flags & (with_flag | RESULT))) {
 629                         result = 0;
 630                         goto cleanup;
 631                 }
 632         }
 633
 634 cleanup:
 635         clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
 636         free(list);
 637
 638         for (i = 0; i < from->nr; i++)
 639                 from->objects[i].item->flags &= ~assign_flag;
 640
 641         return result;
 642 }
 643
 644 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 645                        int cutoff_by_min_date)
 646 {
 647         struct object_array from_objs = OBJECT_ARRAY_INIT;
 648         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
 649         struct commit_list *from_iter = from, *to_iter = to;
 650         int result;
 651         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
 652
 653         while (from_iter) {
 654                 add_object_array(&from_iter->item->object, NULL, &from_objs);
 655
 656                 if (!parse_commit(from_iter->item)) {
 657                         if (from_iter->item->date < min_commit_date)
 658                                 min_commit_date = from_iter->item->date;
 659
 660                         if (from_iter->item->generation < min_generation)
 661                                 min_generation = from_iter->item->generation;
 662                 }
 663
 664                 from_iter = from_iter->next;
 665         }
 666
 667         while (to_iter) {
 668                 if (!parse_commit(to_iter->item)) {
 669                         if (to_iter->item->date < min_commit_date)
 670                                 min_commit_date = to_iter->item->date;
 671
 672                         if (to_iter->item->generation < min_generation)
 673                                 min_generation = to_iter->item->generation;
 674                 }
 675
 676                 to_iter->item->object.flags |= PARENT2;
 677
 678                 to_iter = to_iter->next;
 679         }
 680
 681         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
 682                                               min_commit_date, min_generation);
 683
 684         while (from) {
 685                 clear_commit_marks(from->item, PARENT1);
 686                 from = from->next;
 687         }
 688
 689         while (to) {
 690                 clear_commit_marks(to->item, PARENT2);
 691                 to = to->next;
 692         }
 693
 694         object_array_clear(&from_objs);
 695         return result;
 696 }