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.c"
   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         while (with_commit) {
 281                 struct commit *other;
 282
 283                 other = with_commit->item;
 284                 with_commit = with_commit->next;
 285                 if (in_merge_bases(other, commit))
 286                         return 1;
 287         }
 288         return 0;
 289 }
 290
 291 /*
 292  * Is "commit" an ancestor of one of the "references"?
 293  */
 294 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 295 {
 296         struct commit_list *bases;
 297         int ret = 0, i;
 298         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
 299
 300         if (parse_commit(commit))
 301                 return ret;
 302         for (i = 0; i < nr_reference; i++) {
 303                 if (parse_commit(reference[i]))
 304                         return ret;
 305                 if (reference[i]->generation < min_generation)
 306                         min_generation = reference[i]->generation;
 307         }
 308
 309         if (commit->generation > min_generation)
 310                 return ret;
 311
 312         bases = paint_down_to_common(commit, nr_reference, reference, commit->generation);
 313         if (commit->object.flags & PARENT2)
 314                 ret = 1;
 315         clear_commit_marks(commit, all_flags);
 316         clear_commit_marks_many(nr_reference, reference, all_flags);
 317         free_commit_list(bases);
 318         return ret;
 319 }
 320
 321 /*
 322  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 323  */
 324 int in_merge_bases(struct commit *commit, struct commit *reference)
 325 {
 326         return in_merge_bases_many(commit, 1, &reference);
 327 }
 328
 329 struct commit_list *reduce_heads(struct commit_list *heads)
 330 {
 331         struct commit_list *p;
 332         struct commit_list *result = NULL, **tail = &result;
 333         struct commit **array;
 334         int num_head, i;
 335
 336         if (!heads)
 337                 return NULL;
 338
 339         /* Uniquify */
 340         for (p = heads; p; p = p->next)
 341                 p->item->object.flags &= ~STALE;
 342         for (p = heads, num_head = 0; p; p = p->next) {
 343                 if (p->item->object.flags & STALE)
 344                         continue;
 345                 p->item->object.flags |= STALE;
 346                 num_head++;
 347         }
 348         array = xcalloc(num_head, sizeof(*array));
 349         for (p = heads, i = 0; p; p = p->next) {
 350                 if (p->item->object.flags & STALE) {
 351                         array[i++] = p->item;
 352                         p->item->object.flags &= ~STALE;
 353                 }
 354         }
 355         num_head = remove_redundant(array, num_head);
 356         for (i = 0; i < num_head; i++)
 357                 tail = &commit_list_insert(array[i], tail)->next;
 358         free(array);
 359         return result;
 360 }
 361
 362 void reduce_heads_replace(struct commit_list **heads)
 363 {
 364         struct commit_list *result = reduce_heads(*heads);
 365         free_commit_list(*heads);
 366         *heads = result;
 367 }
 368
 369 static void unmark_and_free(struct commit_list *list, unsigned int mark)
 370 {
 371         while (list) {
 372                 struct commit *commit = pop_commit(&list);
 373                 commit->object.flags &= ~mark;
 374         }
 375 }
 376
 377 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 378 {
 379         struct object *o;
 380         struct commit *old_commit, *new_commit;
 381         struct commit_list *list, *used;
 382         int found = 0;
 383
 384         /*
 385          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
 386          * old_commit.  Otherwise we require --force.
 387          */
 388         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
 389                       NULL, 0);
 390         if (!o || o->type != OBJ_COMMIT)
 391                 return 0;
 392         old_commit = (struct commit *) o;
 393
 394         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
 395                       NULL, 0);
 396         if (!o || o->type != OBJ_COMMIT)
 397                 return 0;
 398         new_commit = (struct commit *) o;
 399
 400         if (parse_commit(new_commit) < 0)
 401                 return 0;
 402
 403         used = list = NULL;
 404         commit_list_insert(new_commit, &list);
 405         while (list) {
 406                 new_commit = pop_most_recent_commit(&list, TMP_MARK);
 407                 commit_list_insert(new_commit, &used);
 408                 if (new_commit == old_commit) {
 409                         found = 1;
 410                         break;
 411                 }
 412         }
 413         unmark_and_free(list, TMP_MARK);
 414         unmark_and_free(used, TMP_MARK);
 415         return found;
 416 }
 417
 418 /*
 419  * Mimicking the real stack, this stack lives on the heap, avoiding stack
 420  * overflows.
 421  *
 422  * At each recursion step, the stack items points to the commits whose
 423  * ancestors are to be inspected.
 424  */
 425 struct contains_stack {
 426         int nr, alloc;
 427         struct contains_stack_entry {
 428                 struct commit *commit;
 429                 struct commit_list *parents;
 430         } *contains_stack;
 431 };
 432
 433 static int in_commit_list(const struct commit_list *want, struct commit *c)
 434 {
 435         for (; want; want = want->next)
 436                 if (!oidcmp(&want->item->object.oid, &c->object.oid))
 437                         return 1;
 438         return 0;
 439 }
 440
 441 /*
 442  * Test whether the candidate is contained in the list.
 443  * Do not recurse to find out, though, but return -1 if inconclusive.
 444  */
 445 static enum contains_result contains_test(struct commit *candidate,
 446                                           const struct commit_list *want,
 447                                           struct contains_cache *cache,
 448                                           uint32_t cutoff)
 449 {
 450         enum contains_result *cached = contains_cache_at(cache, candidate);
 451
 452         /* If we already have the answer cached, return that. */
 453         if (*cached)
 454                 return *cached;
 455
 456         /* or are we it? */
 457         if (in_commit_list(want, candidate)) {
 458                 *cached = CONTAINS_YES;
 459                 return CONTAINS_YES;
 460         }
 461
 462         /* Otherwise, we don't know; prepare to recurse */
 463         parse_commit_or_die(candidate);
 464
 465         if (candidate->generation < cutoff)
 466                 return CONTAINS_NO;
 467
 468         return CONTAINS_UNKNOWN;
 469 }
 470
 471 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
 472 {
 473         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
 474         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
 475         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
 476 }
 477
 478 static enum contains_result contains_tag_algo(struct commit *candidate,
 479                                               const struct commit_list *want,
 480                                               struct contains_cache *cache)
 481 {
 482         struct contains_stack contains_stack = { 0, 0, NULL };
 483         enum contains_result result;
 484         uint32_t cutoff = GENERATION_NUMBER_INFINITY;
 485         const struct commit_list *p;
 486
 487         for (p = want; p; p = p->next) {
 488                 struct commit *c = p->item;
 489                 load_commit_graph_info(the_repository, c);
 490                 if (c->generation < cutoff)
 491                         cutoff = c->generation;
 492         }
 493
 494         result = contains_test(candidate, want, cache, cutoff);
 495         if (result != CONTAINS_UNKNOWN)
 496                 return result;
 497
 498         push_to_contains_stack(candidate, &contains_stack);
 499         while (contains_stack.nr) {
 500                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
 501                 struct commit *commit = entry->commit;
 502                 struct commit_list *parents = entry->parents;
 503
 504                 if (!parents) {
 505                         *contains_cache_at(cache, commit) = CONTAINS_NO;
 506                         contains_stack.nr--;
 507                 }
 508                 /*
 509                  * If we just popped the stack, parents->item has been marked,
 510                  * therefore contains_test will return a meaningful yes/no.
 511                  */
 512                 else switch (contains_test(parents->item, want, cache, cutoff)) {
 513                 case CONTAINS_YES:
 514                         *contains_cache_at(cache, commit) = CONTAINS_YES;
 515                         contains_stack.nr--;
 516                         break;
 517                 case CONTAINS_NO:
 518                         entry->parents = parents->next;
 519                         break;
 520                 case CONTAINS_UNKNOWN:
 521                         push_to_contains_stack(parents->item, &contains_stack);
 522                         break;
 523                 }
 524         }
 525         free(contains_stack.contains_stack);
 526         return contains_test(candidate, want, cache, cutoff);
 527 }
 528
 529 int commit_contains(struct ref_filter *filter, struct commit *commit,
 530                     struct commit_list *list, struct contains_cache *cache)
 531 {
 532         if (filter->with_commit_tag_algo)
 533                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
 534         return is_descendant_of(commit, list);
 535 }
 536
 537 int reachable(struct commit *from, unsigned int with_flag,
 538               unsigned int assign_flag, time_t min_commit_date)
 539 {
 540         struct prio_queue work = { compare_commits_by_commit_date };
 541
 542         prio_queue_put(&work, from);
 543         while (work.nr) {
 544                 struct commit_list *list;
 545                 struct commit *commit = prio_queue_get(&work);
 546
 547                 if (commit->object.flags & with_flag) {
 548                         from->object.flags |= assign_flag;
 549                         break;
 550                 }
 551                 if (!commit->object.parsed)
 552                         parse_object(the_repository, &commit->object.oid);
 553                 if (commit->object.flags & REACHABLE)
 554                         continue;
 555                 commit->object.flags |= REACHABLE;
 556                 if (commit->date < min_commit_date)
 557                         continue;
 558                 for (list = commit->parents; list; list = list->next) {
 559                         struct commit *parent = list->item;
 560                         if (!(parent->object.flags & REACHABLE))
 561                                 prio_queue_put(&work, parent);
 562                 }
 563         }
 564         from->object.flags |= REACHABLE;
 565         clear_commit_marks(from, REACHABLE);
 566         clear_prio_queue(&work);
 567         return (from->object.flags & assign_flag);
 568 }
 569
 570 int can_all_from_reach_with_flag(struct object_array *from,
 571                                  unsigned int with_flag,
 572                                  unsigned int assign_flag,
 573                                  time_t min_commit_date)
 574 {
 575         int i;
 576
 577         for (i = 0; i < from->nr; i++) {
 578                 struct object *from_one = from->objects[i].item;
 579
 580                 if (from_one->flags & assign_flag)
 581                         continue;
 582                 from_one = deref_tag(the_repository, from_one, "a from object", 0);
 583                 if (!from_one || from_one->type != OBJ_COMMIT) {
 584                         /* no way to tell if this is reachable by
 585                          * looking at the ancestry chain alone, so
 586                          * leave a note to ourselves not to worry about
 587                          * this object anymore.
 588                          */
 589                         from->objects[i].item->flags |= assign_flag;
 590                         continue;
 591                 }
 592                 if (!reachable((struct commit *)from_one, with_flag, assign_flag,
 593                                min_commit_date))
 594                         return 0;
 595         }
 596         return 1;
 597 }