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 PARENT1         (1u<<16)
  14 #define PARENT2         (1u<<17)
  15 #define STALE           (1u<<18)
  16 #define RESULT          (1u<<19)
  17
  18 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
  19
  20 static int queue_has_nonstale(struct prio_queue *queue)
  21 {
  22         int i;
  23         for (i = 0; i < queue->nr; i++) {
  24                 struct commit *commit = queue->array[i].data;
  25                 if (!(commit->object.flags & STALE))
  26                         return 1;
  27         }
  28         return 0;
  29 }
  30
  31 /* all input commits in one and twos[] must have been parsed! */
  32 static struct commit_list *paint_down_to_common(struct commit *one, int n,
  33                                                 struct commit **twos,
  34                                                 int min_generation)
  35 {
  36         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
  37         struct commit_list *result = NULL;
  38         int i;
  39         uint32_t last_gen = GENERATION_NUMBER_INFINITY;
  40
  41         one->object.flags |= PARENT1;
  42         if (!n) {
  43                 commit_list_append(one, &result);
  44                 return result;
  45         }
  46         prio_queue_put(&queue, one);
  47
  48         for (i = 0; i < n; i++) {
  49                 twos[i]->object.flags |= PARENT2;
  50                 prio_queue_put(&queue, twos[i]);
  51         }
  52
  53         while (queue_has_nonstale(&queue)) {
  54                 struct commit *commit = prio_queue_get(&queue);
  55                 struct commit_list *parents;
  56                 int flags;
  57
  58                 if (commit->generation > last_gen)
  59                         BUG("bad generation skip %8x > %8x at %s",
  60                             commit->generation, last_gen,
  61                             oid_to_hex(&commit->object.oid));
  62                 last_gen = commit->generation;
  63
  64                 if (commit->generation < min_generation)
  65                         break;
  66
  67                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
  68                 if (flags == (PARENT1 | PARENT2)) {
  69                         if (!(commit->object.flags & RESULT)) {
  70                                 commit->object.flags |= RESULT;
  71                                 commit_list_insert_by_date(commit, &result);
  72                         }
  73                         /* Mark parents of a found merge stale */
  74                         flags |= STALE;
  75                 }
  76                 parents = commit->parents;
  77                 while (parents) {
  78                         struct commit *p = parents->item;
  79                         parents = parents->next;
  80                         if ((p->object.flags & flags) == flags)
  81                                 continue;
  82                         if (parse_commit(p))
  83                                 return NULL;
  84                         p->object.flags |= flags;
  85                         prio_queue_put(&queue, p);
  86                 }
  87         }
  88
  89         clear_prio_queue(&queue);
  90         return result;
  91 }
  92
  93 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
  94 {
  95         struct commit_list *list = NULL;
  96         struct commit_list *result = NULL;
  97         int i;
  98
  99         for (i = 0; i < n; i++) {
 100                 if (one == twos[i])
 101                         /*
 102                          * We do not mark this even with RESULT so we do not
 103                          * have to clean it up.
 104                          */
 105                         return commit_list_insert(one, &result);
 106         }
 107
 108         if (parse_commit(one))
 109                 return NULL;
 110         for (i = 0; i < n; i++) {
 111                 if (parse_commit(twos[i]))
 112                         return NULL;
 113         }
 114
 115         list = paint_down_to_common(one, n, twos, 0);
 116
 117         while (list) {
 118                 struct commit *commit = pop_commit(&list);
 119                 if (!(commit->object.flags & STALE))
 120                         commit_list_insert_by_date(commit, &result);
 121         }
 122         return result;
 123 }
 124
 125 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 126 {
 127         struct commit_list *i, *j, *k, *ret = NULL;
 128
 129         if (!in)
 130                 return ret;
 131
 132         commit_list_insert(in->item, &ret);
 133
 134         for (i = in->next; i; i = i->next) {
 135                 struct commit_list *new_commits = NULL, *end = NULL;
 136
 137                 for (j = ret; j; j = j->next) {
 138                         struct commit_list *bases;
 139                         bases = get_merge_bases(i->item, j->item);
 140                         if (!new_commits)
 141                                 new_commits = bases;
 142                         else
 143                                 end->next = bases;
 144                         for (k = bases; k; k = k->next)
 145                                 end = k;
 146                 }
 147                 ret = new_commits;
 148         }
 149         return ret;
 150 }
 151
 152 static int remove_redundant(struct commit **array, int cnt)
 153 {
 154         /*
 155          * Some commit in the array may be an ancestor of
 156          * another commit.  Move such commit to the end of
 157          * the array, and return the number of commits that
 158          * are independent from each other.
 159          */
 160         struct commit **work;
 161         unsigned char *redundant;
 162         int *filled_index;
 163         int i, j, filled;
 164
 165         work = xcalloc(cnt, sizeof(*work));
 166         redundant = xcalloc(cnt, 1);
 167         ALLOC_ARRAY(filled_index, cnt - 1);
 168
 169         for (i = 0; i < cnt; i++)
 170                 parse_commit(array[i]);
 171         for (i = 0; i < cnt; i++) {
 172                 struct commit_list *common;
 173                 uint32_t min_generation = array[i]->generation;
 174
 175                 if (redundant[i])
 176                         continue;
 177                 for (j = filled = 0; j < cnt; j++) {
 178                         if (i == j || redundant[j])
 179                                 continue;
 180                         filled_index[filled] = j;
 181                         work[filled++] = array[j];
 182
 183                         if (array[j]->generation < min_generation)
 184                                 min_generation = array[j]->generation;
 185                 }
 186                 common = paint_down_to_common(array[i], filled, work,
 187                                               min_generation);
 188                 if (array[i]->object.flags & PARENT2)
 189                         redundant[i] = 1;
 190                 for (j = 0; j < filled; j++)
 191                         if (work[j]->object.flags & PARENT1)
 192                                 redundant[filled_index[j]] = 1;
 193                 clear_commit_marks(array[i], all_flags);
 194                 clear_commit_marks_many(filled, work, all_flags);
 195                 free_commit_list(common);
 196         }
 197
 198         /* Now collect the result */
 199         COPY_ARRAY(work, array, cnt);
 200         for (i = filled = 0; i < cnt; i++)
 201                 if (!redundant[i])
 202                         array[filled++] = work[i];
 203         for (j = filled, i = 0; i < cnt; i++)
 204                 if (redundant[i])
 205                         array[j++] = work[i];
 206         free(work);
 207         free(redundant);
 208         free(filled_index);
 209         return filled;
 210 }
 211
 212 static struct commit_list *get_merge_bases_many_0(struct commit *one,
 213                                                   int n,
 214                                                   struct commit **twos,
 215                                                   int cleanup)
 216 {
 217         struct commit_list *list;
 218         struct commit **rslt;
 219         struct commit_list *result;
 220         int cnt, i;
 221
 222         result = merge_bases_many(one, n, twos);
 223         for (i = 0; i < n; i++) {
 224                 if (one == twos[i])
 225                         return result;
 226         }
 227         if (!result || !result->next) {
 228                 if (cleanup) {
 229                         clear_commit_marks(one, all_flags);
 230                         clear_commit_marks_many(n, twos, all_flags);
 231                 }
 232                 return result;
 233         }
 234
 235         /* There are more than one */
 236         cnt = commit_list_count(result);
 237         rslt = xcalloc(cnt, sizeof(*rslt));
 238         for (list = result, i = 0; list; list = list->next)
 239                 rslt[i++] = list->item;
 240         free_commit_list(result);
 241
 242         clear_commit_marks(one, all_flags);
 243         clear_commit_marks_many(n, twos, all_flags);
 244
 245         cnt = remove_redundant(rslt, cnt);
 246         result = NULL;
 247         for (i = 0; i < cnt; i++)
 248                 commit_list_insert_by_date(rslt[i], &result);
 249         free(rslt);
 250         return result;
 251 }
 252
 253 struct commit_list *get_merge_bases_many(struct commit *one,
 254                                          int n,
 255                                          struct commit **twos)
 256 {
 257         return get_merge_bases_many_0(one, n, twos, 1);
 258 }
 259
 260 struct commit_list *get_merge_bases_many_dirty(struct commit *one,
 261                                                int n,
 262                                                struct commit **twos)
 263 {
 264         return get_merge_bases_many_0(one, n, twos, 0);
 265 }
 266
 267 struct commit_list *get_merge_bases(struct commit *one, struct commit *two)
 268 {
 269         return get_merge_bases_many_0(one, 1, &two, 1);
 270 }
 271
 272 /*
 273  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 274  */
 275 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 276 {
 277         if (!with_commit)
 278                 return 1;
 279         while (with_commit) {
 280                 struct commit *other;
 281
 282                 other = with_commit->item;
 283                 with_commit = with_commit->next;
 284                 if (in_merge_bases(other, commit))
 285                         return 1;
 286         }
 287         return 0;
 288 }
 289
 290 /*
 291  * Is "commit" an ancestor of one of the "references"?
 292  */
 293 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 294 {
 295         struct commit_list *bases;
 296         int ret = 0, i;
 297         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
 298
 299         if (parse_commit(commit))
 300                 return ret;
 301         for (i = 0; i < nr_reference; i++) {
 302                 if (parse_commit(reference[i]))
 303                         return ret;
 304                 if (reference[i]->generation < min_generation)
 305                         min_generation = reference[i]->generation;
 306         }
 307
 308         if (commit->generation > min_generation)
 309                 return ret;
 310
 311         bases = paint_down_to_common(commit, nr_reference, reference, commit->generation);
 312         if (commit->object.flags & PARENT2)
 313                 ret = 1;
 314         clear_commit_marks(commit, all_flags);
 315         clear_commit_marks_many(nr_reference, reference, all_flags);
 316         free_commit_list(bases);
 317         return ret;
 318 }
 319
 320 /*
 321  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 322  */
 323 int in_merge_bases(struct commit *commit, struct commit *reference)
 324 {
 325         return in_merge_bases_many(commit, 1, &reference);
 326 }
 327
 328 struct commit_list *reduce_heads(struct commit_list *heads)
 329 {
 330         struct commit_list *p;
 331         struct commit_list *result = NULL, **tail = &result;
 332         struct commit **array;
 333         int num_head, i;
 334
 335         if (!heads)
 336                 return NULL;
 337
 338         /* Uniquify */
 339         for (p = heads; p; p = p->next)
 340                 p->item->object.flags &= ~STALE;
 341         for (p = heads, num_head = 0; p; p = p->next) {
 342                 if (p->item->object.flags & STALE)
 343                         continue;
 344                 p->item->object.flags |= STALE;
 345                 num_head++;
 346         }
 347         array = xcalloc(num_head, sizeof(*array));
 348         for (p = heads, i = 0; p; p = p->next) {
 349                 if (p->item->object.flags & STALE) {
 350                         array[i++] = p->item;
 351                         p->item->object.flags &= ~STALE;
 352                 }
 353         }
 354         num_head = remove_redundant(array, num_head);
 355         for (i = 0; i < num_head; i++)
 356                 tail = &commit_list_insert(array[i], tail)->next;
 357         free(array);
 358         return result;
 359 }
 360
 361 void reduce_heads_replace(struct commit_list **heads)
 362 {
 363         struct commit_list *result = reduce_heads(*heads);
 364         free_commit_list(*heads);
 365         *heads = result;
 366 }
 367
 368 static void unmark_and_free(struct commit_list *list, unsigned int mark)
 369 {
 370         while (list) {
 371                 struct commit *commit = pop_commit(&list);
 372                 commit->object.flags &= ~mark;
 373         }
 374 }
 375
 376 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 377 {
 378         struct object *o;
 379         struct commit *old_commit, *new_commit;
 380         struct commit_list *list, *used;
 381         int found = 0;
 382
 383         /*
 384          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
 385          * old_commit.  Otherwise we require --force.
 386          */
 387         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
 388                       NULL, 0);
 389         if (!o || o->type != OBJ_COMMIT)
 390                 return 0;
 391         old_commit = (struct commit *) o;
 392
 393         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
 394                       NULL, 0);
 395         if (!o || o->type != OBJ_COMMIT)
 396                 return 0;
 397         new_commit = (struct commit *) o;
 398
 399         if (parse_commit(new_commit) < 0)
 400                 return 0;
 401
 402         used = list = NULL;
 403         commit_list_insert(new_commit, &list);
 404         while (list) {
 405                 new_commit = pop_most_recent_commit(&list, TMP_MARK);
 406                 commit_list_insert(new_commit, &used);
 407                 if (new_commit == old_commit) {
 408                         found = 1;
 409                         break;
 410                 }
 411         }
 412         unmark_and_free(list, TMP_MARK);
 413         unmark_and_free(used, TMP_MARK);
 414         return found;
 415 }
 416
 417 /*
 418  * Mimicking the real stack, this stack lives on the heap, avoiding stack
 419  * overflows.
 420  *
 421  * At each recursion step, the stack items points to the commits whose
 422  * ancestors are to be inspected.
 423  */
 424 struct contains_stack {
 425         int nr, alloc;
 426         struct contains_stack_entry {
 427                 struct commit *commit;
 428                 struct commit_list *parents;
 429         } *contains_stack;
 430 };
 431
 432 static int in_commit_list(const struct commit_list *want, struct commit *c)
 433 {
 434         for (; want; want = want->next)
 435                 if (!oidcmp(&want->item->object.oid, &c->object.oid))
 436                         return 1;
 437         return 0;
 438 }
 439
 440 /*
 441  * Test whether the candidate is contained in the list.
 442  * Do not recurse to find out, though, but return -1 if inconclusive.
 443  */
 444 static enum contains_result contains_test(struct commit *candidate,
 445                                           const struct commit_list *want,
 446                                           struct contains_cache *cache,
 447                                           uint32_t cutoff)
 448 {
 449         enum contains_result *cached = contains_cache_at(cache, candidate);
 450
 451         /* If we already have the answer cached, return that. */
 452         if (*cached)
 453                 return *cached;
 454
 455         /* or are we it? */
 456         if (in_commit_list(want, candidate)) {
 457                 *cached = CONTAINS_YES;
 458                 return CONTAINS_YES;
 459         }
 460
 461         /* Otherwise, we don't know; prepare to recurse */
 462         parse_commit_or_die(candidate);
 463
 464         if (candidate->generation < cutoff)
 465                 return CONTAINS_NO;
 466
 467         return CONTAINS_UNKNOWN;
 468 }
 469
 470 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
 471 {
 472         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
 473         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
 474         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
 475 }
 476
 477 static enum contains_result contains_tag_algo(struct commit *candidate,
 478                                               const struct commit_list *want,
 479                                               struct contains_cache *cache)
 480 {
 481         struct contains_stack contains_stack = { 0, 0, NULL };
 482         enum contains_result result;
 483         uint32_t cutoff = GENERATION_NUMBER_INFINITY;
 484         const struct commit_list *p;
 485
 486         for (p = want; p; p = p->next) {
 487                 struct commit *c = p->item;
 488                 load_commit_graph_info(the_repository, c);
 489                 if (c->generation < cutoff)
 490                         cutoff = c->generation;
 491         }
 492
 493         result = contains_test(candidate, want, cache, cutoff);
 494         if (result != CONTAINS_UNKNOWN)
 495                 return result;
 496
 497         push_to_contains_stack(candidate, &contains_stack);
 498         while (contains_stack.nr) {
 499                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
 500                 struct commit *commit = entry->commit;
 501                 struct commit_list *parents = entry->parents;
 502
 503                 if (!parents) {
 504                         *contains_cache_at(cache, commit) = CONTAINS_NO;
 505                         contains_stack.nr--;
 506                 }
 507                 /*
 508                  * If we just popped the stack, parents->item has been marked,
 509                  * therefore contains_test will return a meaningful yes/no.
 510                  */
 511                 else switch (contains_test(parents->item, want, cache, cutoff)) {
 512                 case CONTAINS_YES:
 513                         *contains_cache_at(cache, commit) = CONTAINS_YES;
 514                         contains_stack.nr--;
 515                         break;
 516                 case CONTAINS_NO:
 517                         entry->parents = parents->next;
 518                         break;
 519                 case CONTAINS_UNKNOWN:
 520                         push_to_contains_stack(parents->item, &contains_stack);
 521                         break;
 522                 }
 523         }
 524         free(contains_stack.contains_stack);
 525         return contains_test(candidate, want, cache, cutoff);
 526 }
 527
 528 int commit_contains(struct ref_filter *filter, struct commit *commit,
 529                     struct commit_list *list, struct contains_cache *cache)
 530 {
 531         if (filter->with_commit_tag_algo)
 532                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
 533         return is_descendant_of(commit, list);
 534 }