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 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 370 {
 371         struct object *o;
 372         struct commit *old_commit, *new_commit;
 373         struct commit_list *old_commit_list = NULL;
 374
 375         /*
 376          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
 377          * old_commit.  Otherwise we require --force.
 378          */
 379         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
 380                       NULL, 0);
 381         if (!o || o->type != OBJ_COMMIT)
 382                 return 0;
 383         old_commit = (struct commit *) o;
 384
 385         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
 386                       NULL, 0);
 387         if (!o || o->type != OBJ_COMMIT)
 388                 return 0;
 389         new_commit = (struct commit *) o;
 390
 391         if (parse_commit(new_commit) < 0)
 392                 return 0;
 393
 394         commit_list_insert(old_commit, &old_commit_list);
 395         return is_descendant_of(new_commit, old_commit_list);
 396 }
 397
 398 /*
 399  * Mimicking the real stack, this stack lives on the heap, avoiding stack
 400  * overflows.
 401  *
 402  * At each recursion step, the stack items points to the commits whose
 403  * ancestors are to be inspected.
 404  */
 405 struct contains_stack {
 406         int nr, alloc;
 407         struct contains_stack_entry {
 408                 struct commit *commit;
 409                 struct commit_list *parents;
 410         } *contains_stack;
 411 };
 412
 413 static int in_commit_list(const struct commit_list *want, struct commit *c)
 414 {
 415         for (; want; want = want->next)
 416                 if (!oidcmp(&want->item->object.oid, &c->object.oid))
 417                         return 1;
 418         return 0;
 419 }
 420
 421 /*
 422  * Test whether the candidate is contained in the list.
 423  * Do not recurse to find out, though, but return -1 if inconclusive.
 424  */
 425 static enum contains_result contains_test(struct commit *candidate,
 426                                           const struct commit_list *want,
 427                                           struct contains_cache *cache,
 428                                           uint32_t cutoff)
 429 {
 430         enum contains_result *cached = contains_cache_at(cache, candidate);
 431
 432         /* If we already have the answer cached, return that. */
 433         if (*cached)
 434                 return *cached;
 435
 436         /* or are we it? */
 437         if (in_commit_list(want, candidate)) {
 438                 *cached = CONTAINS_YES;
 439                 return CONTAINS_YES;
 440         }
 441
 442         /* Otherwise, we don't know; prepare to recurse */
 443         parse_commit_or_die(candidate);
 444
 445         if (candidate->generation < cutoff)
 446                 return CONTAINS_NO;
 447
 448         return CONTAINS_UNKNOWN;
 449 }
 450
 451 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
 452 {
 453         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
 454         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
 455         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
 456 }
 457
 458 static enum contains_result contains_tag_algo(struct commit *candidate,
 459                                               const struct commit_list *want,
 460                                               struct contains_cache *cache)
 461 {
 462         struct contains_stack contains_stack = { 0, 0, NULL };
 463         enum contains_result result;
 464         uint32_t cutoff = GENERATION_NUMBER_INFINITY;
 465         const struct commit_list *p;
 466
 467         for (p = want; p; p = p->next) {
 468                 struct commit *c = p->item;
 469                 load_commit_graph_info(the_repository, c);
 470                 if (c->generation < cutoff)
 471                         cutoff = c->generation;
 472         }
 473
 474         result = contains_test(candidate, want, cache, cutoff);
 475         if (result != CONTAINS_UNKNOWN)
 476                 return result;
 477
 478         push_to_contains_stack(candidate, &contains_stack);
 479         while (contains_stack.nr) {
 480                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
 481                 struct commit *commit = entry->commit;
 482                 struct commit_list *parents = entry->parents;
 483
 484                 if (!parents) {
 485                         *contains_cache_at(cache, commit) = CONTAINS_NO;
 486                         contains_stack.nr--;
 487                 }
 488                 /*
 489                  * If we just popped the stack, parents->item has been marked,
 490                  * therefore contains_test will return a meaningful yes/no.
 491                  */
 492                 else switch (contains_test(parents->item, want, cache, cutoff)) {
 493                 case CONTAINS_YES:
 494                         *contains_cache_at(cache, commit) = CONTAINS_YES;
 495                         contains_stack.nr--;
 496                         break;
 497                 case CONTAINS_NO:
 498                         entry->parents = parents->next;
 499                         break;
 500                 case CONTAINS_UNKNOWN:
 501                         push_to_contains_stack(parents->item, &contains_stack);
 502                         break;
 503                 }
 504         }
 505         free(contains_stack.contains_stack);
 506         return contains_test(candidate, want, cache, cutoff);
 507 }
 508
 509 int commit_contains(struct ref_filter *filter, struct commit *commit,
 510                     struct commit_list *list, struct contains_cache *cache)
 511 {
 512         if (filter->with_commit_tag_algo)
 513                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
 514         return is_descendant_of(commit, list);
 515 }
 516
 517 int reachable(struct commit *from, unsigned int with_flag,
 518               unsigned int assign_flag, time_t min_commit_date)
 519 {
 520         struct prio_queue work = { compare_commits_by_commit_date };
 521
 522         prio_queue_put(&work, from);
 523         while (work.nr) {
 524                 struct commit_list *list;
 525                 struct commit *commit = prio_queue_get(&work);
 526
 527                 if (commit->object.flags & with_flag) {
 528                         from->object.flags |= assign_flag;
 529                         break;
 530                 }
 531                 if (!commit->object.parsed)
 532                         parse_object(the_repository, &commit->object.oid);
 533                 if (commit->object.flags & REACHABLE)
 534                         continue;
 535                 commit->object.flags |= REACHABLE;
 536                 if (commit->date < min_commit_date)
 537                         continue;
 538                 for (list = commit->parents; list; list = list->next) {
 539                         struct commit *parent = list->item;
 540                         if (!(parent->object.flags & REACHABLE))
 541                                 prio_queue_put(&work, parent);
 542                 }
 543         }
 544         from->object.flags |= REACHABLE;
 545         clear_commit_marks(from, REACHABLE);
 546         clear_prio_queue(&work);
 547         return (from->object.flags & assign_flag);
 548 }
 549
 550 int can_all_from_reach_with_flag(struct object_array *from,
 551                                  unsigned int with_flag,
 552                                  unsigned int assign_flag,
 553                                  time_t min_commit_date)
 554 {
 555         int i;
 556
 557         for (i = 0; i < from->nr; i++) {
 558                 struct object *from_one = from->objects[i].item;
 559
 560                 if (from_one->flags & assign_flag)
 561                         continue;
 562                 from_one = deref_tag(the_repository, from_one, "a from object", 0);
 563                 if (!from_one || from_one->type != OBJ_COMMIT) {
 564                         /* no way to tell if this is reachable by
 565                          * looking at the ancestry chain alone, so
 566                          * leave a note to ourselves not to worry about
 567                          * this object anymore.
 568                          */
 569                         from->objects[i].item->flags |= assign_flag;
 570                         continue;
 571                 }
 572                 if (!reachable((struct commit *)from_one, with_flag, assign_flag,
 573                                min_commit_date))
 574                         return 0;
 575         }
 576         return 1;
 577 }
 578
 579 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 580                        int cutoff_by_min_date)
 581 {
 582         struct object_array from_objs = OBJECT_ARRAY_INIT;
 583         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
 584         struct commit_list *from_iter = from, *to_iter = to;
 585         int result;
 586
 587         while (from_iter) {
 588                 add_object_array(&from_iter->item->object, NULL, &from_objs);
 589
 590                 if (!parse_commit(from_iter->item)) {
 591                         if (from_iter->item->date < min_commit_date)
 592                                 min_commit_date = from_iter->item->date;
 593                 }
 594
 595                 from_iter = from_iter->next;
 596         }
 597
 598         while (to_iter) {
 599                 if (!parse_commit(to_iter->item)) {
 600                         if (to_iter->item->date < min_commit_date)
 601                                 min_commit_date = to_iter->item->date;
 602                 }
 603
 604                 to_iter->item->object.flags |= PARENT2;
 605
 606                 to_iter = to_iter->next;
 607         }
 608
 609         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
 610                                               min_commit_date);
 611
 612         while (from) {
 613                 clear_commit_marks(from->item, PARENT1);
 614                 from = from->next;
 615         }
 616
 617         while (to) {
 618                 clear_commit_marks(to->item, PARENT2);
 619                 to = to->next;
 620         }
 621
 622         object_array_clear(&from_objs);
 623         return result;
 624 }