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

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "commit-graph.h"
   4 #include "decorate.h"
   5 #include "prio-queue.h"
   6 #include "tree.h"
   7 #include "ref-filter.h"
   8 #include "revision.h"
   9 #include "tag.h"
  10 #include "commit-reach.h"
  11
  12 /* Remember to update object flag allocation in object.h */
  13 #define 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 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                 parse_commit(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(the_repository, 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 commit *one,
 220                                                   int n,
 221                                                   struct commit **twos,
 222                                                   int cleanup)
 223 {
 224         struct commit_list *list;
 225         struct commit **rslt;
 226         struct commit_list *result;
 227         int cnt, i;
 228
 229         result = merge_bases_many(the_repository, one, n, twos);
 230         for (i = 0; i < n; i++) {
 231                 if (one == twos[i])
 232                         return result;
 233         }
 234         if (!result || !result->next) {
 235                 if (cleanup) {
 236                         clear_commit_marks(one, all_flags);
 237                         clear_commit_marks_many(n, twos, all_flags);
 238                 }
 239                 return result;
 240         }
 241
 242         /* There are more than one */
 243         cnt = commit_list_count(result);
 244         rslt = xcalloc(cnt, sizeof(*rslt));
 245         for (list = result, i = 0; list; list = list->next)
 246                 rslt[i++] = list->item;
 247         free_commit_list(result);
 248
 249         clear_commit_marks(one, all_flags);
 250         clear_commit_marks_many(n, twos, all_flags);
 251
 252         cnt = remove_redundant(rslt, cnt);
 253         result = NULL;
 254         for (i = 0; i < cnt; i++)
 255                 commit_list_insert_by_date(rslt[i], &result);
 256         free(rslt);
 257         return result;
 258 }
 259
 260 struct commit_list *get_merge_bases_many(struct commit *one,
 261                                          int n,
 262                                          struct commit **twos)
 263 {
 264         return get_merge_bases_many_0(one, n, twos, 1);
 265 }
 266
 267 struct commit_list *get_merge_bases_many_dirty(struct commit *one,
 268                                                int n,
 269                                                struct commit **twos)
 270 {
 271         return get_merge_bases_many_0(one, n, twos, 0);
 272 }
 273
 274 struct commit_list *get_merge_bases(struct commit *one, struct commit *two)
 275 {
 276         return get_merge_bases_many_0(one, 1, &two, 1);
 277 }
 278
 279 /*
 280  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 281  */
 282 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 283 {
 284         if (!with_commit)
 285                 return 1;
 286
 287         if (generation_numbers_enabled(the_repository)) {
 288                 struct commit_list *from_list = NULL;
 289                 int result;
 290                 commit_list_insert(commit, &from_list);
 291                 result = can_all_from_reach(from_list, with_commit, 0);
 292                 free_commit_list(from_list);
 293                 return result;
 294         } else {
 295                 while (with_commit) {
 296                         struct commit *other;
 297
 298                         other = with_commit->item;
 299                         with_commit = with_commit->next;
 300                         if (in_merge_bases(other, commit))
 301                                 return 1;
 302                 }
 303                 return 0;
 304         }
 305 }
 306
 307 /*
 308  * Is "commit" an ancestor of one of the "references"?
 309  */
 310 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 311 {
 312         struct commit_list *bases;
 313         int ret = 0, i;
 314         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
 315
 316         if (parse_commit(commit))
 317                 return ret;
 318         for (i = 0; i < nr_reference; i++) {
 319                 if (parse_commit(reference[i]))
 320                         return ret;
 321                 if (reference[i]->generation < min_generation)
 322                         min_generation = reference[i]->generation;
 323         }
 324
 325         if (commit->generation > min_generation)
 326                 return ret;
 327
 328         bases = paint_down_to_common(the_repository, commit,
 329                                      nr_reference, reference,
 330                                      commit->generation);
 331         if (commit->object.flags & PARENT2)
 332                 ret = 1;
 333         clear_commit_marks(commit, all_flags);
 334         clear_commit_marks_many(nr_reference, reference, all_flags);
 335         free_commit_list(bases);
 336         return ret;
 337 }
 338
 339 /*
 340  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 341  */
 342 int in_merge_bases(struct commit *commit, struct commit *reference)
 343 {
 344         return in_merge_bases_many(commit, 1, &reference);
 345 }
 346
 347 struct commit_list *reduce_heads(struct commit_list *heads)
 348 {
 349         struct commit_list *p;
 350         struct commit_list *result = NULL, **tail = &result;
 351         struct commit **array;
 352         int num_head, i;
 353
 354         if (!heads)
 355                 return NULL;
 356
 357         /* Uniquify */
 358         for (p = heads; p; p = p->next)
 359                 p->item->object.flags &= ~STALE;
 360         for (p = heads, num_head = 0; p; p = p->next) {
 361                 if (p->item->object.flags & STALE)
 362                         continue;
 363                 p->item->object.flags |= STALE;
 364                 num_head++;
 365         }
 366         array = xcalloc(num_head, sizeof(*array));
 367         for (p = heads, i = 0; p; p = p->next) {
 368                 if (p->item->object.flags & STALE) {
 369                         array[i++] = p->item;
 370                         p->item->object.flags &= ~STALE;
 371                 }
 372         }
 373         num_head = remove_redundant(array, num_head);
 374         for (i = 0; i < num_head; i++)
 375                 tail = &commit_list_insert(array[i], tail)->next;
 376         free(array);
 377         return result;
 378 }
 379
 380 void reduce_heads_replace(struct commit_list **heads)
 381 {
 382         struct commit_list *result = reduce_heads(*heads);
 383         free_commit_list(*heads);
 384         *heads = result;
 385 }
 386
 387 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 388 {
 389         struct object *o;
 390         struct commit *old_commit, *new_commit;
 391         struct commit_list *old_commit_list = NULL;
 392
 393         /*
 394          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
 395          * old_commit.  Otherwise we require --force.
 396          */
 397         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
 398                       NULL, 0);
 399         if (!o || o->type != OBJ_COMMIT)
 400                 return 0;
 401         old_commit = (struct commit *) o;
 402
 403         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
 404                       NULL, 0);
 405         if (!o || o->type != OBJ_COMMIT)
 406                 return 0;
 407         new_commit = (struct commit *) o;
 408
 409         if (parse_commit(new_commit) < 0)
 410                 return 0;
 411
 412         commit_list_insert(old_commit, &old_commit_list);
 413         return is_descendant_of(new_commit, old_commit_list);
 414 }
 415
 416 /*
 417  * Mimicking the real stack, this stack lives on the heap, avoiding stack
 418  * overflows.
 419  *
 420  * At each recursion step, the stack items points to the commits whose
 421  * ancestors are to be inspected.
 422  */
 423 struct contains_stack {
 424         int nr, alloc;
 425         struct contains_stack_entry {
 426                 struct commit *commit;
 427                 struct commit_list *parents;
 428         } *contains_stack;
 429 };
 430
 431 static int in_commit_list(const struct commit_list *want, struct commit *c)
 432 {
 433         for (; want; want = want->next)
 434                 if (oideq(&want->item->object.oid, &c->object.oid))
 435                         return 1;
 436         return 0;
 437 }
 438
 439 /*
 440  * Test whether the candidate is contained in the list.
 441  * Do not recurse to find out, though, but return -1 if inconclusive.
 442  */
 443 static enum contains_result contains_test(struct commit *candidate,
 444                                           const struct commit_list *want,
 445                                           struct contains_cache *cache,
 446                                           uint32_t cutoff)
 447 {
 448         enum contains_result *cached = contains_cache_at(cache, candidate);
 449
 450         /* If we already have the answer cached, return that. */
 451         if (*cached)
 452                 return *cached;
 453
 454         /* or are we it? */
 455         if (in_commit_list(want, candidate)) {
 456                 *cached = CONTAINS_YES;
 457                 return CONTAINS_YES;
 458         }
 459
 460         /* Otherwise, we don't know; prepare to recurse */
 461         parse_commit_or_die(candidate);
 462
 463         if (candidate->generation < cutoff)
 464                 return CONTAINS_NO;
 465
 466         return CONTAINS_UNKNOWN;
 467 }
 468
 469 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
 470 {
 471         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
 472         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
 473         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
 474 }
 475
 476 static enum contains_result contains_tag_algo(struct commit *candidate,
 477                                               const struct commit_list *want,
 478                                               struct contains_cache *cache)
 479 {
 480         struct contains_stack contains_stack = { 0, 0, NULL };
 481         enum contains_result result;
 482         uint32_t cutoff = GENERATION_NUMBER_INFINITY;
 483         const struct commit_list *p;
 484
 485         for (p = want; p; p = p->next) {
 486                 struct commit *c = p->item;
 487                 load_commit_graph_info(the_repository, c);
 488                 if (c->generation < cutoff)
 489                         cutoff = c->generation;
 490         }
 491
 492         result = contains_test(candidate, want, cache, cutoff);
 493         if (result != CONTAINS_UNKNOWN)
 494                 return result;
 495
 496         push_to_contains_stack(candidate, &contains_stack);
 497         while (contains_stack.nr) {
 498                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
 499                 struct commit *commit = entry->commit;
 500                 struct commit_list *parents = entry->parents;
 501
 502                 if (!parents) {
 503                         *contains_cache_at(cache, commit) = CONTAINS_NO;
 504                         contains_stack.nr--;
 505                 }
 506                 /*
 507                  * If we just popped the stack, parents->item has been marked,
 508                  * therefore contains_test will return a meaningful yes/no.
 509                  */
 510                 else switch (contains_test(parents->item, want, cache, cutoff)) {
 511                 case CONTAINS_YES:
 512                         *contains_cache_at(cache, commit) = CONTAINS_YES;
 513                         contains_stack.nr--;
 514                         break;
 515                 case CONTAINS_NO:
 516                         entry->parents = parents->next;
 517                         break;
 518                 case CONTAINS_UNKNOWN:
 519                         push_to_contains_stack(parents->item, &contains_stack);
 520                         break;
 521                 }
 522         }
 523         free(contains_stack.contains_stack);
 524         return contains_test(candidate, want, cache, cutoff);
 525 }
 526
 527 int commit_contains(struct ref_filter *filter, struct commit *commit,
 528                     struct commit_list *list, struct contains_cache *cache)
 529 {
 530         if (filter->with_commit_tag_algo)
 531                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
 532         return is_descendant_of(commit, list);
 533 }
 534
 535 static int compare_commits_by_gen(const void *_a, const void *_b)
 536 {
 537         const struct commit *a = (const struct commit *)_a;
 538         const struct commit *b = (const struct commit *)_b;
 539
 540         if (a->generation < b->generation)
 541                 return -1;
 542         if (a->generation > b->generation)
 543                 return 1;
 544         return 0;
 545 }
 546
 547 int can_all_from_reach_with_flag(struct object_array *from,
 548                                  unsigned int with_flag,
 549                                  unsigned int assign_flag,
 550                                  time_t min_commit_date,
 551                                  uint32_t min_generation)
 552 {
 553         struct commit **list = NULL;
 554         int i;
 555         int nr_commits;
 556         int result = 1;
 557
 558         ALLOC_ARRAY(list, from->nr);
 559         nr_commits = 0;
 560         for (i = 0; i < from->nr; i++) {
 561                 struct object *from_one = from->objects[i].item;
 562
 563                 if (!from_one || from_one->flags & assign_flag)
 564                         continue;
 565
 566                 from_one = deref_tag(the_repository, from_one,
 567                                      "a from object", 0);
 568                 if (!from_one || from_one->type != OBJ_COMMIT) {
 569                         /*
 570                          * no way to tell if this is reachable by
 571                          * looking at the ancestry chain alone, so
 572                          * leave a note to ourselves not to worry about
 573                          * this object anymore.
 574                          */
 575                         from->objects[i].item->flags |= assign_flag;
 576                         continue;
 577                 }
 578
 579                 list[nr_commits] = (struct commit *)from_one;
 580                 if (parse_commit(list[nr_commits]) ||
 581                     list[nr_commits]->generation < min_generation) {
 582                         result = 0;
 583                         goto cleanup;
 584                 }
 585
 586                 nr_commits++;
 587         }
 588
 589         QSORT(list, nr_commits, compare_commits_by_gen);
 590
 591         for (i = 0; i < nr_commits; i++) {
 592                 /* DFS from list[i] */
 593                 struct commit_list *stack = NULL;
 594
 595                 list[i]->object.flags |= assign_flag;
 596                 commit_list_insert(list[i], &stack);
 597
 598                 while (stack) {
 599                         struct commit_list *parent;
 600
 601                         if (stack->item->object.flags & with_flag) {
 602                                 pop_commit(&stack);
 603                                 continue;
 604                         }
 605
 606                         for (parent = stack->item->parents; parent; parent = parent->next) {
 607                                 if (parent->item->object.flags & (with_flag | RESULT))
 608                                         stack->item->object.flags |= RESULT;
 609
 610                                 if (!(parent->item->object.flags & assign_flag)) {
 611                                         parent->item->object.flags |= assign_flag;
 612
 613                                         if (parse_commit(parent->item) ||
 614                                             parent->item->date < min_commit_date ||
 615                                             parent->item->generation < min_generation)
 616                                                 continue;
 617
 618                                         commit_list_insert(parent->item, &stack);
 619                                         break;
 620                                 }
 621                         }
 622
 623                         if (!parent)
 624                                 pop_commit(&stack);
 625                 }
 626
 627                 if (!(list[i]->object.flags & (with_flag | RESULT))) {
 628                         result = 0;
 629                         goto cleanup;
 630                 }
 631         }
 632
 633 cleanup:
 634         clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
 635         free(list);
 636
 637         for (i = 0; i < from->nr; i++)
 638                 from->objects[i].item->flags &= ~assign_flag;
 639
 640         return result;
 641 }
 642
 643 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 644                        int cutoff_by_min_date)
 645 {
 646         struct object_array from_objs = OBJECT_ARRAY_INIT;
 647         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
 648         struct commit_list *from_iter = from, *to_iter = to;
 649         int result;
 650         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
 651
 652         while (from_iter) {
 653                 add_object_array(&from_iter->item->object, NULL, &from_objs);
 654
 655                 if (!parse_commit(from_iter->item)) {
 656                         if (from_iter->item->date < min_commit_date)
 657                                 min_commit_date = from_iter->item->date;
 658
 659                         if (from_iter->item->generation < min_generation)
 660                                 min_generation = from_iter->item->generation;
 661                 }
 662
 663                 from_iter = from_iter->next;
 664         }
 665
 666         while (to_iter) {
 667                 if (!parse_commit(to_iter->item)) {
 668                         if (to_iter->item->date < min_commit_date)
 669                                 min_commit_date = to_iter->item->date;
 670
 671                         if (to_iter->item->generation < min_generation)
 672                                 min_generation = to_iter->item->generation;
 673                 }
 674
 675                 to_iter->item->object.flags |= PARENT2;
 676
 677                 to_iter = to_iter->next;
 678         }
 679
 680         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
 681                                               min_commit_date, min_generation);
 682
 683         while (from) {
 684                 clear_commit_marks(from->item, PARENT1);
 685                 from = from->next;
 686         }
 687
 688         while (to) {
 689                 clear_commit_marks(to->item, PARENT2);
 690                 to = to->next;
 691         }
 692
 693         object_array_clear(&from_objs);
 694         return result;
 695 }