Merge branch 'hd/show-one-mergetag-fix'
[git] / 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 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 repository *r,
33                                                 struct commit *one, int n,
34                                                 struct commit **twos,
35                                                 int min_generation)
36 {
37         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
38         struct commit_list *result = NULL;
39         int i;
40         uint32_t last_gen = GENERATION_NUMBER_INFINITY;
41
42         if (!min_generation)
43                 queue.compare = compare_commits_by_commit_date;
44
45         one->object.flags |= PARENT1;
46         if (!n) {
47                 commit_list_append(one, &result);
48                 return result;
49         }
50         prio_queue_put(&queue, one);
51
52         for (i = 0; i < n; i++) {
53                 twos[i]->object.flags |= PARENT2;
54                 prio_queue_put(&queue, twos[i]);
55         }
56
57         while (queue_has_nonstale(&queue)) {
58                 struct commit *commit = prio_queue_get(&queue);
59                 struct commit_list *parents;
60                 int flags;
61
62                 if (min_generation && commit->generation > last_gen)
63                         BUG("bad generation skip %8x > %8x at %s",
64                             commit->generation, last_gen,
65                             oid_to_hex(&commit->object.oid));
66                 last_gen = commit->generation;
67
68                 if (commit->generation < min_generation)
69                         break;
70
71                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
72                 if (flags == (PARENT1 | PARENT2)) {
73                         if (!(commit->object.flags & RESULT)) {
74                                 commit->object.flags |= RESULT;
75                                 commit_list_insert_by_date(commit, &result);
76                         }
77                         /* Mark parents of a found merge stale */
78                         flags |= STALE;
79                 }
80                 parents = commit->parents;
81                 while (parents) {
82                         struct commit *p = parents->item;
83                         parents = parents->next;
84                         if ((p->object.flags & flags) == flags)
85                                 continue;
86                         if (repo_parse_commit(r, p))
87                                 return NULL;
88                         p->object.flags |= flags;
89                         prio_queue_put(&queue, p);
90                 }
91         }
92
93         clear_prio_queue(&queue);
94         return result;
95 }
96
97 static struct commit_list *merge_bases_many(struct repository *r,
98                                             struct commit *one, int n,
99                                             struct commit **twos)
100 {
101         struct commit_list *list = NULL;
102         struct commit_list *result = NULL;
103         int i;
104
105         for (i = 0; i < n; i++) {
106                 if (one == twos[i])
107                         /*
108                          * We do not mark this even with RESULT so we do not
109                          * have to clean it up.
110                          */
111                         return commit_list_insert(one, &result);
112         }
113
114         if (repo_parse_commit(r, one))
115                 return NULL;
116         for (i = 0; i < n; i++) {
117                 if (repo_parse_commit(r, twos[i]))
118                         return NULL;
119         }
120
121         list = paint_down_to_common(r, one, n, twos, 0);
122
123         while (list) {
124                 struct commit *commit = pop_commit(&list);
125                 if (!(commit->object.flags & STALE))
126                         commit_list_insert_by_date(commit, &result);
127         }
128         return result;
129 }
130
131 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
132 {
133         struct commit_list *i, *j, *k, *ret = NULL;
134
135         if (!in)
136                 return ret;
137
138         commit_list_insert(in->item, &ret);
139
140         for (i = in->next; i; i = i->next) {
141                 struct commit_list *new_commits = NULL, *end = NULL;
142
143                 for (j = ret; j; j = j->next) {
144                         struct commit_list *bases;
145                         bases = get_merge_bases(i->item, j->item);
146                         if (!new_commits)
147                                 new_commits = bases;
148                         else
149                                 end->next = bases;
150                         for (k = bases; k; k = k->next)
151                                 end = k;
152                 }
153                 ret = new_commits;
154         }
155         return ret;
156 }
157
158 static int remove_redundant(struct repository *r, struct commit **array, int cnt)
159 {
160         /*
161          * Some commit in the array may be an ancestor of
162          * another commit.  Move such commit to the end of
163          * the array, and return the number of commits that
164          * are independent from each other.
165          */
166         struct commit **work;
167         unsigned char *redundant;
168         int *filled_index;
169         int i, j, filled;
170
171         work = xcalloc(cnt, sizeof(*work));
172         redundant = xcalloc(cnt, 1);
173         ALLOC_ARRAY(filled_index, cnt - 1);
174
175         for (i = 0; i < cnt; i++)
176                 repo_parse_commit(r, array[i]);
177         for (i = 0; i < cnt; i++) {
178                 struct commit_list *common;
179                 uint32_t min_generation = array[i]->generation;
180
181                 if (redundant[i])
182                         continue;
183                 for (j = filled = 0; j < cnt; j++) {
184                         if (i == j || redundant[j])
185                                 continue;
186                         filled_index[filled] = j;
187                         work[filled++] = array[j];
188
189                         if (array[j]->generation < min_generation)
190                                 min_generation = array[j]->generation;
191                 }
192                 common = paint_down_to_common(r, array[i], filled,
193                                               work, min_generation);
194                 if (array[i]->object.flags & PARENT2)
195                         redundant[i] = 1;
196                 for (j = 0; j < filled; j++)
197                         if (work[j]->object.flags & PARENT1)
198                                 redundant[filled_index[j]] = 1;
199                 clear_commit_marks(array[i], all_flags);
200                 clear_commit_marks_many(filled, work, all_flags);
201                 free_commit_list(common);
202         }
203
204         /* Now collect the result */
205         COPY_ARRAY(work, array, cnt);
206         for (i = filled = 0; i < cnt; i++)
207                 if (!redundant[i])
208                         array[filled++] = work[i];
209         for (j = filled, i = 0; i < cnt; i++)
210                 if (redundant[i])
211                         array[j++] = work[i];
212         free(work);
213         free(redundant);
214         free(filled_index);
215         return filled;
216 }
217
218 static struct commit_list *get_merge_bases_many_0(struct repository *r,
219                                                   struct commit *one,
220                                                   int n,
221                                                   struct commit **twos,
222                                                   int cleanup)
223 {
224         struct commit_list *list;
225         struct commit **rslt;
226         struct commit_list *result;
227         int cnt, i;
228
229         result = merge_bases_many(r, one, n, twos);
230         for (i = 0; i < n; i++) {
231                 if (one == twos[i])
232                         return result;
233         }
234         if (!result || !result->next) {
235                 if (cleanup) {
236                         clear_commit_marks(one, all_flags);
237                         clear_commit_marks_many(n, twos, all_flags);
238                 }
239                 return result;
240         }
241
242         /* There are more than one */
243         cnt = commit_list_count(result);
244         rslt = xcalloc(cnt, sizeof(*rslt));
245         for (list = result, i = 0; list; list = list->next)
246                 rslt[i++] = list->item;
247         free_commit_list(result);
248
249         clear_commit_marks(one, all_flags);
250         clear_commit_marks_many(n, twos, all_flags);
251
252         cnt = remove_redundant(r, rslt, cnt);
253         result = NULL;
254         for (i = 0; i < cnt; i++)
255                 commit_list_insert_by_date(rslt[i], &result);
256         free(rslt);
257         return result;
258 }
259
260 struct commit_list *repo_get_merge_bases_many(struct repository *r,
261                                               struct commit *one,
262                                               int n,
263                                               struct commit **twos)
264 {
265         return get_merge_bases_many_0(r, one, n, twos, 1);
266 }
267
268 struct commit_list *repo_get_merge_bases_many_dirty(struct repository *r,
269                                                     struct commit *one,
270                                                     int n,
271                                                     struct commit **twos)
272 {
273         return get_merge_bases_many_0(r, one, n, twos, 0);
274 }
275
276 struct commit_list *repo_get_merge_bases(struct repository *r,
277                                          struct commit *one,
278                                          struct commit *two)
279 {
280         return get_merge_bases_many_0(r, one, 1, &two, 1);
281 }
282
283 /*
284  * Is "commit" a descendant of one of the elements on the "with_commit" list?
285  */
286 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
287 {
288         if (!with_commit)
289                 return 1;
290
291         if (generation_numbers_enabled(the_repository)) {
292                 struct commit_list *from_list = NULL;
293                 int result;
294                 commit_list_insert(commit, &from_list);
295                 result = can_all_from_reach(from_list, with_commit, 0);
296                 free_commit_list(from_list);
297                 return result;
298         } else {
299                 while (with_commit) {
300                         struct commit *other;
301
302                         other = with_commit->item;
303                         with_commit = with_commit->next;
304                         if (in_merge_bases(other, commit))
305                                 return 1;
306                 }
307                 return 0;
308         }
309 }
310
311 /*
312  * Is "commit" an ancestor of one of the "references"?
313  */
314 int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
315                              int nr_reference, struct commit **reference)
316 {
317         struct commit_list *bases;
318         int ret = 0, i;
319         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
320
321         if (repo_parse_commit(r, commit))
322                 return ret;
323         for (i = 0; i < nr_reference; i++) {
324                 if (repo_parse_commit(r, reference[i]))
325                         return ret;
326                 if (reference[i]->generation < min_generation)
327                         min_generation = reference[i]->generation;
328         }
329
330         if (commit->generation > min_generation)
331                 return ret;
332
333         bases = paint_down_to_common(r, commit,
334                                      nr_reference, reference,
335                                      commit->generation);
336         if (commit->object.flags & PARENT2)
337                 ret = 1;
338         clear_commit_marks(commit, all_flags);
339         clear_commit_marks_many(nr_reference, reference, all_flags);
340         free_commit_list(bases);
341         return ret;
342 }
343
344 /*
345  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
346  */
347 int repo_in_merge_bases(struct repository *r,
348                         struct commit *commit,
349                         struct commit *reference)
350 {
351         return repo_in_merge_bases_many(r, commit, 1, &reference);
352 }
353
354 struct commit_list *reduce_heads(struct commit_list *heads)
355 {
356         struct commit_list *p;
357         struct commit_list *result = NULL, **tail = &result;
358         struct commit **array;
359         int num_head, i;
360
361         if (!heads)
362                 return NULL;
363
364         /* Uniquify */
365         for (p = heads; p; p = p->next)
366                 p->item->object.flags &= ~STALE;
367         for (p = heads, num_head = 0; p; p = p->next) {
368                 if (p->item->object.flags & STALE)
369                         continue;
370                 p->item->object.flags |= STALE;
371                 num_head++;
372         }
373         array = xcalloc(num_head, sizeof(*array));
374         for (p = heads, i = 0; p; p = p->next) {
375                 if (p->item->object.flags & STALE) {
376                         array[i++] = p->item;
377                         p->item->object.flags &= ~STALE;
378                 }
379         }
380         num_head = remove_redundant(the_repository, array, num_head);
381         for (i = 0; i < num_head; i++)
382                 tail = &commit_list_insert(array[i], tail)->next;
383         free(array);
384         return result;
385 }
386
387 void reduce_heads_replace(struct commit_list **heads)
388 {
389         struct commit_list *result = reduce_heads(*heads);
390         free_commit_list(*heads);
391         *heads = result;
392 }
393
394 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
395 {
396         struct object *o;
397         struct commit *old_commit, *new_commit;
398         struct commit_list *old_commit_list = NULL;
399
400         /*
401          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
402          * old_commit.  Otherwise we require --force.
403          */
404         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
405                       NULL, 0);
406         if (!o || o->type != OBJ_COMMIT)
407                 return 0;
408         old_commit = (struct commit *) o;
409
410         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
411                       NULL, 0);
412         if (!o || o->type != OBJ_COMMIT)
413                 return 0;
414         new_commit = (struct commit *) o;
415
416         if (parse_commit(new_commit) < 0)
417                 return 0;
418
419         commit_list_insert(old_commit, &old_commit_list);
420         return is_descendant_of(new_commit, old_commit_list);
421 }
422
423 /*
424  * Mimicking the real stack, this stack lives on the heap, avoiding stack
425  * overflows.
426  *
427  * At each recursion step, the stack items points to the commits whose
428  * ancestors are to be inspected.
429  */
430 struct contains_stack {
431         int nr, alloc;
432         struct contains_stack_entry {
433                 struct commit *commit;
434                 struct commit_list *parents;
435         } *contains_stack;
436 };
437
438 static int in_commit_list(const struct commit_list *want, struct commit *c)
439 {
440         for (; want; want = want->next)
441                 if (oideq(&want->item->object.oid, &c->object.oid))
442                         return 1;
443         return 0;
444 }
445
446 /*
447  * Test whether the candidate is contained in the list.
448  * Do not recurse to find out, though, but return -1 if inconclusive.
449  */
450 static enum contains_result contains_test(struct commit *candidate,
451                                           const struct commit_list *want,
452                                           struct contains_cache *cache,
453                                           uint32_t cutoff)
454 {
455         enum contains_result *cached = contains_cache_at(cache, candidate);
456
457         /* If we already have the answer cached, return that. */
458         if (*cached)
459                 return *cached;
460
461         /* or are we it? */
462         if (in_commit_list(want, candidate)) {
463                 *cached = CONTAINS_YES;
464                 return CONTAINS_YES;
465         }
466
467         /* Otherwise, we don't know; prepare to recurse */
468         parse_commit_or_die(candidate);
469
470         if (candidate->generation < cutoff)
471                 return CONTAINS_NO;
472
473         return CONTAINS_UNKNOWN;
474 }
475
476 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
477 {
478         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
479         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
480         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
481 }
482
483 static enum contains_result contains_tag_algo(struct commit *candidate,
484                                               const struct commit_list *want,
485                                               struct contains_cache *cache)
486 {
487         struct contains_stack contains_stack = { 0, 0, NULL };
488         enum contains_result result;
489         uint32_t cutoff = GENERATION_NUMBER_INFINITY;
490         const struct commit_list *p;
491
492         for (p = want; p; p = p->next) {
493                 struct commit *c = p->item;
494                 load_commit_graph_info(the_repository, c);
495                 if (c->generation < cutoff)
496                         cutoff = c->generation;
497         }
498
499         result = contains_test(candidate, want, cache, cutoff);
500         if (result != CONTAINS_UNKNOWN)
501                 return result;
502
503         push_to_contains_stack(candidate, &contains_stack);
504         while (contains_stack.nr) {
505                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
506                 struct commit *commit = entry->commit;
507                 struct commit_list *parents = entry->parents;
508
509                 if (!parents) {
510                         *contains_cache_at(cache, commit) = CONTAINS_NO;
511                         contains_stack.nr--;
512                 }
513                 /*
514                  * If we just popped the stack, parents->item has been marked,
515                  * therefore contains_test will return a meaningful yes/no.
516                  */
517                 else switch (contains_test(parents->item, want, cache, cutoff)) {
518                 case CONTAINS_YES:
519                         *contains_cache_at(cache, commit) = CONTAINS_YES;
520                         contains_stack.nr--;
521                         break;
522                 case CONTAINS_NO:
523                         entry->parents = parents->next;
524                         break;
525                 case CONTAINS_UNKNOWN:
526                         push_to_contains_stack(parents->item, &contains_stack);
527                         break;
528                 }
529         }
530         free(contains_stack.contains_stack);
531         return contains_test(candidate, want, cache, cutoff);
532 }
533
534 int commit_contains(struct ref_filter *filter, struct commit *commit,
535                     struct commit_list *list, struct contains_cache *cache)
536 {
537         if (filter->with_commit_tag_algo)
538                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
539         return is_descendant_of(commit, list);
540 }
541
542 static int compare_commits_by_gen(const void *_a, const void *_b)
543 {
544         const struct commit *a = *(const struct commit * const *)_a;
545         const struct commit *b = *(const struct commit * const *)_b;
546
547         if (a->generation < b->generation)
548                 return -1;
549         if (a->generation > b->generation)
550                 return 1;
551         return 0;
552 }
553
554 int can_all_from_reach_with_flag(struct object_array *from,
555                                  unsigned int with_flag,
556                                  unsigned int assign_flag,
557                                  time_t min_commit_date,
558                                  uint32_t min_generation)
559 {
560         struct commit **list = NULL;
561         int i;
562         int nr_commits;
563         int result = 1;
564
565         ALLOC_ARRAY(list, from->nr);
566         nr_commits = 0;
567         for (i = 0; i < from->nr; i++) {
568                 struct object *from_one = from->objects[i].item;
569
570                 if (!from_one || from_one->flags & assign_flag)
571                         continue;
572
573                 from_one = deref_tag(the_repository, from_one,
574                                      "a from object", 0);
575                 if (!from_one || from_one->type != OBJ_COMMIT) {
576                         /*
577                          * no way to tell if this is reachable by
578                          * looking at the ancestry chain alone, so
579                          * leave a note to ourselves not to worry about
580                          * this object anymore.
581                          */
582                         from->objects[i].item->flags |= assign_flag;
583                         continue;
584                 }
585
586                 list[nr_commits] = (struct commit *)from_one;
587                 if (parse_commit(list[nr_commits]) ||
588                     list[nr_commits]->generation < min_generation) {
589                         result = 0;
590                         goto cleanup;
591                 }
592
593                 nr_commits++;
594         }
595
596         QSORT(list, nr_commits, compare_commits_by_gen);
597
598         for (i = 0; i < nr_commits; i++) {
599                 /* DFS from list[i] */
600                 struct commit_list *stack = NULL;
601
602                 list[i]->object.flags |= assign_flag;
603                 commit_list_insert(list[i], &stack);
604
605                 while (stack) {
606                         struct commit_list *parent;
607
608                         if (stack->item->object.flags & (with_flag | RESULT)) {
609                                 pop_commit(&stack);
610                                 if (stack)
611                                         stack->item->object.flags |= RESULT;
612                                 continue;
613                         }
614
615                         for (parent = stack->item->parents; parent; parent = parent->next) {
616                                 if (parent->item->object.flags & (with_flag | RESULT))
617                                         stack->item->object.flags |= RESULT;
618
619                                 if (!(parent->item->object.flags & assign_flag)) {
620                                         parent->item->object.flags |= assign_flag;
621
622                                         if (parse_commit(parent->item) ||
623                                             parent->item->date < min_commit_date ||
624                                             parent->item->generation < min_generation)
625                                                 continue;
626
627                                         commit_list_insert(parent->item, &stack);
628                                         break;
629                                 }
630                         }
631
632                         if (!parent)
633                                 pop_commit(&stack);
634                 }
635
636                 if (!(list[i]->object.flags & (with_flag | RESULT))) {
637                         result = 0;
638                         goto cleanup;
639                 }
640         }
641
642 cleanup:
643         clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
644         free(list);
645
646         for (i = 0; i < from->nr; i++)
647                 from->objects[i].item->flags &= ~assign_flag;
648
649         return result;
650 }
651
652 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
653                        int cutoff_by_min_date)
654 {
655         struct object_array from_objs = OBJECT_ARRAY_INIT;
656         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
657         struct commit_list *from_iter = from, *to_iter = to;
658         int result;
659         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
660
661         while (from_iter) {
662                 add_object_array(&from_iter->item->object, NULL, &from_objs);
663
664                 if (!parse_commit(from_iter->item)) {
665                         if (from_iter->item->date < min_commit_date)
666                                 min_commit_date = from_iter->item->date;
667
668                         if (from_iter->item->generation < min_generation)
669                                 min_generation = from_iter->item->generation;
670                 }
671
672                 from_iter = from_iter->next;
673         }
674
675         while (to_iter) {
676                 if (!parse_commit(to_iter->item)) {
677                         if (to_iter->item->date < min_commit_date)
678                                 min_commit_date = to_iter->item->date;
679
680                         if (to_iter->item->generation < min_generation)
681                                 min_generation = to_iter->item->generation;
682                 }
683
684                 to_iter->item->object.flags |= PARENT2;
685
686                 to_iter = to_iter->next;
687         }
688
689         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
690                                               min_commit_date, min_generation);
691
692         while (from) {
693                 clear_commit_marks(from->item, PARENT1);
694                 from = from->next;
695         }
696
697         while (to) {
698                 clear_commit_marks(to->item, PARENT2);
699                 to = to->next;
700         }
701
702         object_array_clear(&from_objs);
703         return result;
704 }
705
706 struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
707                                          struct commit **to, int nr_to,
708                                          unsigned int reachable_flag)
709 {
710         struct commit **item;
711         struct commit *current;
712         struct commit_list *found_commits = NULL;
713         struct commit **to_last = to + nr_to;
714         struct commit **from_last = from + nr_from;
715         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
716         int num_to_find = 0;
717
718         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
719
720         for (item = to; item < to_last; item++) {
721                 struct commit *c = *item;
722
723                 parse_commit(c);
724                 if (c->generation < min_generation)
725                         min_generation = c->generation;
726
727                 if (!(c->object.flags & PARENT1)) {
728                         c->object.flags |= PARENT1;
729                         num_to_find++;
730                 }
731         }
732
733         for (item = from; item < from_last; item++) {
734                 struct commit *c = *item;
735                 if (!(c->object.flags & PARENT2)) {
736                         c->object.flags |= PARENT2;
737                         parse_commit(c);
738
739                         prio_queue_put(&queue, *item);
740                 }
741         }
742
743         while (num_to_find && (current = prio_queue_get(&queue)) != NULL) {
744                 struct commit_list *parents;
745
746                 if (current->object.flags & PARENT1) {
747                         current->object.flags &= ~PARENT1;
748                         current->object.flags |= reachable_flag;
749                         commit_list_insert(current, &found_commits);
750                         num_to_find--;
751                 }
752
753                 for (parents = current->parents; parents; parents = parents->next) {
754                         struct commit *p = parents->item;
755
756                         parse_commit(p);
757
758                         if (p->generation < min_generation)
759                                 continue;
760
761                         if (p->object.flags & PARENT2)
762                                 continue;
763
764                         p->object.flags |= PARENT2;
765                         prio_queue_put(&queue, p);
766                 }
767         }
768
769         clear_commit_marks_many(nr_to, to, PARENT1);
770         clear_commit_marks_many(nr_from, from, PARENT2);
771
772         return found_commits;
773 }