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