checkout: remove duplicate code
[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 REACHABLE       (1u<<15)
14 #define PARENT1         (1u<<16)
15 #define PARENT2         (1u<<17)
16 #define STALE           (1u<<18)
17 #define RESULT          (1u<<19)
18
19 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
20
21 static int queue_has_nonstale(struct prio_queue *queue)
22 {
23         int i;
24         for (i = 0; i < queue->nr; i++) {
25                 struct commit *commit = queue->array[i].data;
26                 if (!(commit->object.flags & STALE))
27                         return 1;
28         }
29         return 0;
30 }
31
32 /* all input commits in one and twos[] must have been parsed! */
33 static struct commit_list *paint_down_to_common(struct repository *r,
34                                                 struct commit *one, int n,
35                                                 struct commit **twos,
36                                                 int min_generation)
37 {
38         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
39         struct commit_list *result = NULL;
40         int i;
41         uint32_t last_gen = GENERATION_NUMBER_INFINITY;
42
43         if (!min_generation)
44                 queue.compare = compare_commits_by_commit_date;
45
46         one->object.flags |= PARENT1;
47         if (!n) {
48                 commit_list_append(one, &result);
49                 return result;
50         }
51         prio_queue_put(&queue, one);
52
53         for (i = 0; i < n; i++) {
54                 twos[i]->object.flags |= PARENT2;
55                 prio_queue_put(&queue, twos[i]);
56         }
57
58         while (queue_has_nonstale(&queue)) {
59                 struct commit *commit = prio_queue_get(&queue);
60                 struct commit_list *parents;
61                 int flags;
62
63                 if (min_generation && commit->generation > last_gen)
64                         BUG("bad generation skip %8x > %8x at %s",
65                             commit->generation, last_gen,
66                             oid_to_hex(&commit->object.oid));
67                 last_gen = commit->generation;
68
69                 if (commit->generation < min_generation)
70                         break;
71
72                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
73                 if (flags == (PARENT1 | PARENT2)) {
74                         if (!(commit->object.flags & RESULT)) {
75                                 commit->object.flags |= RESULT;
76                                 commit_list_insert_by_date(commit, &result);
77                         }
78                         /* Mark parents of a found merge stale */
79                         flags |= STALE;
80                 }
81                 parents = commit->parents;
82                 while (parents) {
83                         struct commit *p = parents->item;
84                         parents = parents->next;
85                         if ((p->object.flags & flags) == flags)
86                                 continue;
87                         if (repo_parse_commit(r, p))
88                                 return NULL;
89                         p->object.flags |= flags;
90                         prio_queue_put(&queue, p);
91                 }
92         }
93
94         clear_prio_queue(&queue);
95         return result;
96 }
97
98 static struct commit_list *merge_bases_many(struct repository *r,
99                                             struct commit *one, int n,
100                                             struct commit **twos)
101 {
102         struct commit_list *list = NULL;
103         struct commit_list *result = NULL;
104         int i;
105
106         for (i = 0; i < n; i++) {
107                 if (one == twos[i])
108                         /*
109                          * We do not mark this even with RESULT so we do not
110                          * have to clean it up.
111                          */
112                         return commit_list_insert(one, &result);
113         }
114
115         if (repo_parse_commit(r, one))
116                 return NULL;
117         for (i = 0; i < n; i++) {
118                 if (repo_parse_commit(r, twos[i]))
119                         return NULL;
120         }
121
122         list = paint_down_to_common(r, one, n, twos, 0);
123
124         while (list) {
125                 struct commit *commit = pop_commit(&list);
126                 if (!(commit->object.flags & STALE))
127                         commit_list_insert_by_date(commit, &result);
128         }
129         return result;
130 }
131
132 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
133 {
134         struct commit_list *i, *j, *k, *ret = NULL;
135
136         if (!in)
137                 return ret;
138
139         commit_list_insert(in->item, &ret);
140
141         for (i = in->next; i; i = i->next) {
142                 struct commit_list *new_commits = NULL, *end = NULL;
143
144                 for (j = ret; j; j = j->next) {
145                         struct commit_list *bases;
146                         bases = get_merge_bases(i->item, j->item);
147                         if (!new_commits)
148                                 new_commits = bases;
149                         else
150                                 end->next = bases;
151                         for (k = bases; k; k = k->next)
152                                 end = k;
153                 }
154                 ret = new_commits;
155         }
156         return ret;
157 }
158
159 static int remove_redundant(struct repository *r, struct commit **array, int cnt)
160 {
161         /*
162          * Some commit in the array may be an ancestor of
163          * another commit.  Move such commit to the end of
164          * the array, and return the number of commits that
165          * are independent from each other.
166          */
167         struct commit **work;
168         unsigned char *redundant;
169         int *filled_index;
170         int i, j, filled;
171
172         work = xcalloc(cnt, sizeof(*work));
173         redundant = xcalloc(cnt, 1);
174         ALLOC_ARRAY(filled_index, cnt - 1);
175
176         for (i = 0; i < cnt; i++)
177                 repo_parse_commit(r, array[i]);
178         for (i = 0; i < cnt; i++) {
179                 struct commit_list *common;
180                 uint32_t min_generation = array[i]->generation;
181
182                 if (redundant[i])
183                         continue;
184                 for (j = filled = 0; j < cnt; j++) {
185                         if (i == j || redundant[j])
186                                 continue;
187                         filled_index[filled] = j;
188                         work[filled++] = array[j];
189
190                         if (array[j]->generation < min_generation)
191                                 min_generation = array[j]->generation;
192                 }
193                 common = paint_down_to_common(r, array[i], filled,
194                                               work, min_generation);
195                 if (array[i]->object.flags & PARENT2)
196                         redundant[i] = 1;
197                 for (j = 0; j < filled; j++)
198                         if (work[j]->object.flags & PARENT1)
199                                 redundant[filled_index[j]] = 1;
200                 clear_commit_marks(array[i], all_flags);
201                 clear_commit_marks_many(filled, work, all_flags);
202                 free_commit_list(common);
203         }
204
205         /* Now collect the result */
206         COPY_ARRAY(work, array, cnt);
207         for (i = filled = 0; i < cnt; i++)
208                 if (!redundant[i])
209                         array[filled++] = work[i];
210         for (j = filled, i = 0; i < cnt; i++)
211                 if (redundant[i])
212                         array[j++] = work[i];
213         free(work);
214         free(redundant);
215         free(filled_index);
216         return filled;
217 }
218
219 static struct commit_list *get_merge_bases_many_0(struct repository *r,
220                                                   struct commit *one,
221                                                   int n,
222                                                   struct commit **twos,
223                                                   int cleanup)
224 {
225         struct commit_list *list;
226         struct commit **rslt;
227         struct commit_list *result;
228         int cnt, i;
229
230         result = merge_bases_many(r, one, n, twos);
231         for (i = 0; i < n; i++) {
232                 if (one == twos[i])
233                         return result;
234         }
235         if (!result || !result->next) {
236                 if (cleanup) {
237                         clear_commit_marks(one, all_flags);
238                         clear_commit_marks_many(n, twos, all_flags);
239                 }
240                 return result;
241         }
242
243         /* There are more than one */
244         cnt = commit_list_count(result);
245         rslt = xcalloc(cnt, sizeof(*rslt));
246         for (list = result, i = 0; list; list = list->next)
247                 rslt[i++] = list->item;
248         free_commit_list(result);
249
250         clear_commit_marks(one, all_flags);
251         clear_commit_marks_many(n, twos, all_flags);
252
253         cnt = remove_redundant(r, rslt, cnt);
254         result = NULL;
255         for (i = 0; i < cnt; i++)
256                 commit_list_insert_by_date(rslt[i], &result);
257         free(rslt);
258         return result;
259 }
260
261 struct commit_list *repo_get_merge_bases_many(struct repository *r,
262                                               struct commit *one,
263                                               int n,
264                                               struct commit **twos)
265 {
266         return get_merge_bases_many_0(r, one, n, twos, 1);
267 }
268
269 struct commit_list *repo_get_merge_bases_many_dirty(struct repository *r,
270                                                     struct commit *one,
271                                                     int n,
272                                                     struct commit **twos)
273 {
274         return get_merge_bases_many_0(r, one, n, twos, 0);
275 }
276
277 struct commit_list *repo_get_merge_bases(struct repository *r,
278                                          struct commit *one,
279                                          struct commit *two)
280 {
281         return get_merge_bases_many_0(r, one, 1, &two, 1);
282 }
283
284 /*
285  * Is "commit" a descendant of one of the elements on the "with_commit" list?
286  */
287 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
288 {
289         if (!with_commit)
290                 return 1;
291
292         if (generation_numbers_enabled(the_repository)) {
293                 struct commit_list *from_list = NULL;
294                 int result;
295                 commit_list_insert(commit, &from_list);
296                 result = can_all_from_reach(from_list, with_commit, 0);
297                 free_commit_list(from_list);
298                 return result;
299         } else {
300                 while (with_commit) {
301                         struct commit *other;
302
303                         other = with_commit->item;
304                         with_commit = with_commit->next;
305                         if (in_merge_bases(other, commit))
306                                 return 1;
307                 }
308                 return 0;
309         }
310 }
311
312 /*
313  * Is "commit" an ancestor of one of the "references"?
314  */
315 int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
316                              int nr_reference, struct commit **reference)
317 {
318         struct commit_list *bases;
319         int ret = 0, i;
320         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
321
322         if (repo_parse_commit(r, commit))
323                 return ret;
324         for (i = 0; i < nr_reference; i++) {
325                 if (repo_parse_commit(r, reference[i]))
326                         return ret;
327                 if (reference[i]->generation < min_generation)
328                         min_generation = reference[i]->generation;
329         }
330
331         if (commit->generation > min_generation)
332                 return ret;
333
334         bases = paint_down_to_common(r, commit,
335                                      nr_reference, reference,
336                                      commit->generation);
337         if (commit->object.flags & PARENT2)
338                 ret = 1;
339         clear_commit_marks(commit, all_flags);
340         clear_commit_marks_many(nr_reference, reference, all_flags);
341         free_commit_list(bases);
342         return ret;
343 }
344
345 /*
346  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
347  */
348 int repo_in_merge_bases(struct repository *r,
349                         struct commit *commit,
350                         struct commit *reference)
351 {
352         return repo_in_merge_bases_many(r, commit, 1, &reference);
353 }
354
355 struct commit_list *reduce_heads(struct commit_list *heads)
356 {
357         struct commit_list *p;
358         struct commit_list *result = NULL, **tail = &result;
359         struct commit **array;
360         int num_head, i;
361
362         if (!heads)
363                 return NULL;
364
365         /* Uniquify */
366         for (p = heads; p; p = p->next)
367                 p->item->object.flags &= ~STALE;
368         for (p = heads, num_head = 0; p; p = p->next) {
369                 if (p->item->object.flags & STALE)
370                         continue;
371                 p->item->object.flags |= STALE;
372                 num_head++;
373         }
374         array = xcalloc(num_head, sizeof(*array));
375         for (p = heads, i = 0; p; p = p->next) {
376                 if (p->item->object.flags & STALE) {
377                         array[i++] = p->item;
378                         p->item->object.flags &= ~STALE;
379                 }
380         }
381         num_head = remove_redundant(the_repository, array, num_head);
382         for (i = 0; i < num_head; i++)
383                 tail = &commit_list_insert(array[i], tail)->next;
384         free(array);
385         return result;
386 }
387
388 void reduce_heads_replace(struct commit_list **heads)
389 {
390         struct commit_list *result = reduce_heads(*heads);
391         free_commit_list(*heads);
392         *heads = result;
393 }
394
395 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
396 {
397         struct object *o;
398         struct commit *old_commit, *new_commit;
399         struct commit_list *old_commit_list = NULL;
400
401         /*
402          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
403          * old_commit.  Otherwise we require --force.
404          */
405         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
406                       NULL, 0);
407         if (!o || o->type != OBJ_COMMIT)
408                 return 0;
409         old_commit = (struct commit *) o;
410
411         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
412                       NULL, 0);
413         if (!o || o->type != OBJ_COMMIT)
414                 return 0;
415         new_commit = (struct commit *) o;
416
417         if (parse_commit(new_commit) < 0)
418                 return 0;
419
420         commit_list_insert(old_commit, &old_commit_list);
421         return is_descendant_of(new_commit, old_commit_list);
422 }
423
424 /*
425  * Mimicking the real stack, this stack lives on the heap, avoiding stack
426  * overflows.
427  *
428  * At each recursion step, the stack items points to the commits whose
429  * ancestors are to be inspected.
430  */
431 struct contains_stack {
432         int nr, alloc;
433         struct contains_stack_entry {
434                 struct commit *commit;
435                 struct commit_list *parents;
436         } *contains_stack;
437 };
438
439 static int in_commit_list(const struct commit_list *want, struct commit *c)
440 {
441         for (; want; want = want->next)
442                 if (oideq(&want->item->object.oid, &c->object.oid))
443                         return 1;
444         return 0;
445 }
446
447 /*
448  * Test whether the candidate is contained in the list.
449  * Do not recurse to find out, though, but return -1 if inconclusive.
450  */
451 static enum contains_result contains_test(struct commit *candidate,
452                                           const struct commit_list *want,
453                                           struct contains_cache *cache,
454                                           uint32_t cutoff)
455 {
456         enum contains_result *cached = contains_cache_at(cache, candidate);
457
458         /* If we already have the answer cached, return that. */
459         if (*cached)
460                 return *cached;
461
462         /* or are we it? */
463         if (in_commit_list(want, candidate)) {
464                 *cached = CONTAINS_YES;
465                 return CONTAINS_YES;
466         }
467
468         /* Otherwise, we don't know; prepare to recurse */
469         parse_commit_or_die(candidate);
470
471         if (candidate->generation < cutoff)
472                 return CONTAINS_NO;
473
474         return CONTAINS_UNKNOWN;
475 }
476
477 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
478 {
479         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
480         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
481         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
482 }
483
484 static enum contains_result contains_tag_algo(struct commit *candidate,
485                                               const struct commit_list *want,
486                                               struct contains_cache *cache)
487 {
488         struct contains_stack contains_stack = { 0, 0, NULL };
489         enum contains_result result;
490         uint32_t cutoff = GENERATION_NUMBER_INFINITY;
491         const struct commit_list *p;
492
493         for (p = want; p; p = p->next) {
494                 struct commit *c = p->item;
495                 load_commit_graph_info(the_repository, c);
496                 if (c->generation < cutoff)
497                         cutoff = c->generation;
498         }
499
500         result = contains_test(candidate, want, cache, cutoff);
501         if (result != CONTAINS_UNKNOWN)
502                 return result;
503
504         push_to_contains_stack(candidate, &contains_stack);
505         while (contains_stack.nr) {
506                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
507                 struct commit *commit = entry->commit;
508                 struct commit_list *parents = entry->parents;
509
510                 if (!parents) {
511                         *contains_cache_at(cache, commit) = CONTAINS_NO;
512                         contains_stack.nr--;
513                 }
514                 /*
515                  * If we just popped the stack, parents->item has been marked,
516                  * therefore contains_test will return a meaningful yes/no.
517                  */
518                 else switch (contains_test(parents->item, want, cache, cutoff)) {
519                 case CONTAINS_YES:
520                         *contains_cache_at(cache, commit) = CONTAINS_YES;
521                         contains_stack.nr--;
522                         break;
523                 case CONTAINS_NO:
524                         entry->parents = parents->next;
525                         break;
526                 case CONTAINS_UNKNOWN:
527                         push_to_contains_stack(parents->item, &contains_stack);
528                         break;
529                 }
530         }
531         free(contains_stack.contains_stack);
532         return contains_test(candidate, want, cache, cutoff);
533 }
534
535 int commit_contains(struct ref_filter *filter, struct commit *commit,
536                     struct commit_list *list, struct contains_cache *cache)
537 {
538         if (filter->with_commit_tag_algo)
539                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
540         return is_descendant_of(commit, list);
541 }
542
543 static int compare_commits_by_gen(const void *_a, const void *_b)
544 {
545         const struct commit *a = *(const struct commit * const *)_a;
546         const struct commit *b = *(const struct commit * const *)_b;
547
548         if (a->generation < b->generation)
549                 return -1;
550         if (a->generation > b->generation)
551                 return 1;
552         return 0;
553 }
554
555 int can_all_from_reach_with_flag(struct object_array *from,
556                                  unsigned int with_flag,
557                                  unsigned int assign_flag,
558                                  time_t min_commit_date,
559                                  uint32_t min_generation)
560 {
561         struct commit **list = NULL;
562         int i;
563         int nr_commits;
564         int result = 1;
565
566         ALLOC_ARRAY(list, from->nr);
567         nr_commits = 0;
568         for (i = 0; i < from->nr; i++) {
569                 struct object *from_one = from->objects[i].item;
570
571                 if (!from_one || from_one->flags & assign_flag)
572                         continue;
573
574                 from_one = deref_tag(the_repository, from_one,
575                                      "a from object", 0);
576                 if (!from_one || from_one->type != OBJ_COMMIT) {
577                         /*
578                          * no way to tell if this is reachable by
579                          * looking at the ancestry chain alone, so
580                          * leave a note to ourselves not to worry about
581                          * this object anymore.
582                          */
583                         from->objects[i].item->flags |= assign_flag;
584                         continue;
585                 }
586
587                 list[nr_commits] = (struct commit *)from_one;
588                 if (parse_commit(list[nr_commits]) ||
589                     list[nr_commits]->generation < min_generation) {
590                         result = 0;
591                         goto cleanup;
592                 }
593
594                 nr_commits++;
595         }
596
597         QSORT(list, nr_commits, compare_commits_by_gen);
598
599         for (i = 0; i < nr_commits; i++) {
600                 /* DFS from list[i] */
601                 struct commit_list *stack = NULL;
602
603                 list[i]->object.flags |= assign_flag;
604                 commit_list_insert(list[i], &stack);
605
606                 while (stack) {
607                         struct commit_list *parent;
608
609                         if (stack->item->object.flags & (with_flag | RESULT)) {
610                                 pop_commit(&stack);
611                                 if (stack)
612                                         stack->item->object.flags |= RESULT;
613                                 continue;
614                         }
615
616                         for (parent = stack->item->parents; parent; parent = parent->next) {
617                                 if (parent->item->object.flags & (with_flag | RESULT))
618                                         stack->item->object.flags |= RESULT;
619
620                                 if (!(parent->item->object.flags & assign_flag)) {
621                                         parent->item->object.flags |= assign_flag;
622
623                                         if (parse_commit(parent->item) ||
624                                             parent->item->date < min_commit_date ||
625                                             parent->item->generation < min_generation)
626                                                 continue;
627
628                                         commit_list_insert(parent->item, &stack);
629                                         break;
630                                 }
631                         }
632
633                         if (!parent)
634                                 pop_commit(&stack);
635                 }
636
637                 if (!(list[i]->object.flags & (with_flag | RESULT))) {
638                         result = 0;
639                         goto cleanup;
640                 }
641         }
642
643 cleanup:
644         clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
645         free(list);
646
647         for (i = 0; i < from->nr; i++)
648                 from->objects[i].item->flags &= ~assign_flag;
649
650         return result;
651 }
652
653 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
654                        int cutoff_by_min_date)
655 {
656         struct object_array from_objs = OBJECT_ARRAY_INIT;
657         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
658         struct commit_list *from_iter = from, *to_iter = to;
659         int result;
660         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
661
662         while (from_iter) {
663                 add_object_array(&from_iter->item->object, NULL, &from_objs);
664
665                 if (!parse_commit(from_iter->item)) {
666                         if (from_iter->item->date < min_commit_date)
667                                 min_commit_date = from_iter->item->date;
668
669                         if (from_iter->item->generation < min_generation)
670                                 min_generation = from_iter->item->generation;
671                 }
672
673                 from_iter = from_iter->next;
674         }
675
676         while (to_iter) {
677                 if (!parse_commit(to_iter->item)) {
678                         if (to_iter->item->date < min_commit_date)
679                                 min_commit_date = to_iter->item->date;
680
681                         if (to_iter->item->generation < min_generation)
682                                 min_generation = to_iter->item->generation;
683                 }
684
685                 to_iter->item->object.flags |= PARENT2;
686
687                 to_iter = to_iter->next;
688         }
689
690         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
691                                               min_commit_date, min_generation);
692
693         while (from) {
694                 clear_commit_marks(from->item, PARENT1);
695                 from = from->next;
696         }
697
698         while (to) {
699                 clear_commit_marks(to->item, PARENT2);
700                 to = to->next;
701         }
702
703         object_array_clear(&from_objs);
704         return result;
705 }
706
707 struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
708                                          struct commit **to, int nr_to,
709                                          unsigned int reachable_flag)
710 {
711         struct commit **item;
712         struct commit *current;
713         struct commit_list *found_commits = NULL;
714         struct commit **to_last = to + nr_to;
715         struct commit **from_last = from + nr_from;
716         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
717         int num_to_find = 0;
718
719         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
720
721         for (item = to; item < to_last; item++) {
722                 struct commit *c = *item;
723
724                 parse_commit(c);
725                 if (c->generation < min_generation)
726                         min_generation = c->generation;
727
728                 if (!(c->object.flags & PARENT1)) {
729                         c->object.flags |= PARENT1;
730                         num_to_find++;
731                 }
732         }
733
734         for (item = from; item < from_last; item++) {
735                 struct commit *c = *item;
736                 if (!(c->object.flags & PARENT2)) {
737                         c->object.flags |= PARENT2;
738                         parse_commit(c);
739
740                         prio_queue_put(&queue, *item);
741                 }
742         }
743
744         while (num_to_find && (current = prio_queue_get(&queue)) != NULL) {
745                 struct commit_list *parents;
746
747                 if (current->object.flags & PARENT1) {
748                         current->object.flags &= ~PARENT1;
749                         current->object.flags |= reachable_flag;
750                         commit_list_insert(current, &found_commits);
751                         num_to_find--;
752                 }
753
754                 for (parents = current->parents; parents; parents = parents->next) {
755                         struct commit *p = parents->item;
756
757                         parse_commit(p);
758
759                         if (p->generation < min_generation)
760                                 continue;
761
762                         if (p->object.flags & PARENT2)
763                                 continue;
764
765                         p->object.flags |= PARENT2;
766                         prio_queue_put(&queue, p);
767                 }
768         }
769
770         clear_commit_marks_many(nr_to, to, PARENT1);
771         clear_commit_marks_many(nr_from, from, PARENT2);
772
773         return found_commits;
774 }