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