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