l10n: zh_TW.po: v2.31.0 round 2 (15 untranslated)
[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 compare_commits_by_gen(const void *_a, const void *_b)
21 {
22         const struct commit *a = *(const struct commit * const *)_a;
23         const struct commit *b = *(const struct commit * const *)_b;
24
25         timestamp_t generation_a = commit_graph_generation(a);
26         timestamp_t generation_b = commit_graph_generation(b);
27
28         if (generation_a < generation_b)
29                 return -1;
30         if (generation_a > generation_b)
31                 return 1;
32         if (a->date < b->date)
33                 return -1;
34         if (a->date > b->date)
35                 return 1;
36         return 0;
37 }
38
39 static int queue_has_nonstale(struct prio_queue *queue)
40 {
41         int i;
42         for (i = 0; i < queue->nr; i++) {
43                 struct commit *commit = queue->array[i].data;
44                 if (!(commit->object.flags & STALE))
45                         return 1;
46         }
47         return 0;
48 }
49
50 /* all input commits in one and twos[] must have been parsed! */
51 static struct commit_list *paint_down_to_common(struct repository *r,
52                                                 struct commit *one, int n,
53                                                 struct commit **twos,
54                                                 timestamp_t min_generation)
55 {
56         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
57         struct commit_list *result = NULL;
58         int i;
59         timestamp_t last_gen = GENERATION_NUMBER_INFINITY;
60
61         if (!min_generation && !corrected_commit_dates_enabled(r))
62                 queue.compare = compare_commits_by_commit_date;
63
64         one->object.flags |= PARENT1;
65         if (!n) {
66                 commit_list_append(one, &result);
67                 return result;
68         }
69         prio_queue_put(&queue, one);
70
71         for (i = 0; i < n; i++) {
72                 twos[i]->object.flags |= PARENT2;
73                 prio_queue_put(&queue, twos[i]);
74         }
75
76         while (queue_has_nonstale(&queue)) {
77                 struct commit *commit = prio_queue_get(&queue);
78                 struct commit_list *parents;
79                 int flags;
80                 timestamp_t generation = commit_graph_generation(commit);
81
82                 if (min_generation && generation > last_gen)
83                         BUG("bad generation skip %"PRItime" > %"PRItime" at %s",
84                             generation, last_gen,
85                             oid_to_hex(&commit->object.oid));
86                 last_gen = generation;
87
88                 if (generation < min_generation)
89                         break;
90
91                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
92                 if (flags == (PARENT1 | PARENT2)) {
93                         if (!(commit->object.flags & RESULT)) {
94                                 commit->object.flags |= RESULT;
95                                 commit_list_insert_by_date(commit, &result);
96                         }
97                         /* Mark parents of a found merge stale */
98                         flags |= STALE;
99                 }
100                 parents = commit->parents;
101                 while (parents) {
102                         struct commit *p = parents->item;
103                         parents = parents->next;
104                         if ((p->object.flags & flags) == flags)
105                                 continue;
106                         if (repo_parse_commit(r, p))
107                                 return NULL;
108                         p->object.flags |= flags;
109                         prio_queue_put(&queue, p);
110                 }
111         }
112
113         clear_prio_queue(&queue);
114         return result;
115 }
116
117 static struct commit_list *merge_bases_many(struct repository *r,
118                                             struct commit *one, int n,
119                                             struct commit **twos)
120 {
121         struct commit_list *list = NULL;
122         struct commit_list *result = NULL;
123         int i;
124
125         for (i = 0; i < n; i++) {
126                 if (one == twos[i])
127                         /*
128                          * We do not mark this even with RESULT so we do not
129                          * have to clean it up.
130                          */
131                         return commit_list_insert(one, &result);
132         }
133
134         if (repo_parse_commit(r, one))
135                 return NULL;
136         for (i = 0; i < n; i++) {
137                 if (repo_parse_commit(r, twos[i]))
138                         return NULL;
139         }
140
141         list = paint_down_to_common(r, one, n, twos, 0);
142
143         while (list) {
144                 struct commit *commit = pop_commit(&list);
145                 if (!(commit->object.flags & STALE))
146                         commit_list_insert_by_date(commit, &result);
147         }
148         return result;
149 }
150
151 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
152 {
153         struct commit_list *i, *j, *k, *ret = NULL;
154
155         if (!in)
156                 return ret;
157
158         commit_list_insert(in->item, &ret);
159
160         for (i = in->next; i; i = i->next) {
161                 struct commit_list *new_commits = NULL, *end = NULL;
162
163                 for (j = ret; j; j = j->next) {
164                         struct commit_list *bases;
165                         bases = get_merge_bases(i->item, j->item);
166                         if (!new_commits)
167                                 new_commits = bases;
168                         else
169                                 end->next = bases;
170                         for (k = bases; k; k = k->next)
171                                 end = k;
172                 }
173                 ret = new_commits;
174         }
175         return ret;
176 }
177
178 static int remove_redundant_no_gen(struct repository *r,
179                                    struct commit **array, int cnt)
180 {
181         struct commit **work;
182         unsigned char *redundant;
183         int *filled_index;
184         int i, j, filled;
185
186         work = xcalloc(cnt, sizeof(*work));
187         redundant = xcalloc(cnt, 1);
188         ALLOC_ARRAY(filled_index, cnt - 1);
189
190         for (i = 0; i < cnt; i++)
191                 repo_parse_commit(r, array[i]);
192         for (i = 0; i < cnt; i++) {
193                 struct commit_list *common;
194                 timestamp_t min_generation = commit_graph_generation(array[i]);
195
196                 if (redundant[i])
197                         continue;
198                 for (j = filled = 0; j < cnt; j++) {
199                         timestamp_t curr_generation;
200                         if (i == j || redundant[j])
201                                 continue;
202                         filled_index[filled] = j;
203                         work[filled++] = array[j];
204
205                         curr_generation = commit_graph_generation(array[j]);
206                         if (curr_generation < min_generation)
207                                 min_generation = curr_generation;
208                 }
209                 common = paint_down_to_common(r, array[i], filled,
210                                               work, min_generation);
211                 if (array[i]->object.flags & PARENT2)
212                         redundant[i] = 1;
213                 for (j = 0; j < filled; j++)
214                         if (work[j]->object.flags & PARENT1)
215                                 redundant[filled_index[j]] = 1;
216                 clear_commit_marks(array[i], all_flags);
217                 clear_commit_marks_many(filled, work, all_flags);
218                 free_commit_list(common);
219         }
220
221         /* Now collect the result */
222         COPY_ARRAY(work, array, cnt);
223         for (i = filled = 0; i < cnt; i++)
224                 if (!redundant[i])
225                         array[filled++] = work[i];
226         free(work);
227         free(redundant);
228         free(filled_index);
229         return filled;
230 }
231
232 static int remove_redundant_with_gen(struct repository *r,
233                                      struct commit **array, int cnt)
234 {
235         int i, count_non_stale = 0, count_still_independent = cnt;
236         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
237         struct commit **walk_start, **sorted;
238         size_t walk_start_nr = 0, walk_start_alloc = cnt;
239         int min_gen_pos = 0;
240
241         /*
242          * Sort the input by generation number, ascending. This allows
243          * us to increase the "min_generation" limit when we discover
244          * the commit with lowest generation is STALE. The index
245          * min_gen_pos points to the current position within 'array'
246          * that is not yet known to be STALE.
247          */
248         ALLOC_ARRAY(sorted, cnt);
249         COPY_ARRAY(sorted, array, cnt);
250         QSORT(sorted, cnt, compare_commits_by_gen);
251         min_generation = commit_graph_generation(sorted[0]);
252
253         ALLOC_ARRAY(walk_start, walk_start_alloc);
254
255         /* Mark all parents of the input as STALE */
256         for (i = 0; i < cnt; i++) {
257                 struct commit_list *parents;
258
259                 repo_parse_commit(r, array[i]);
260                 array[i]->object.flags |= RESULT;
261                 parents = array[i]->parents;
262
263                 while (parents) {
264                         repo_parse_commit(r, parents->item);
265                         if (!(parents->item->object.flags & STALE)) {
266                                 parents->item->object.flags |= STALE;
267                                 ALLOC_GROW(walk_start, walk_start_nr + 1, walk_start_alloc);
268                                 walk_start[walk_start_nr++] = parents->item;
269                         }
270                         parents = parents->next;
271                 }
272         }
273
274         QSORT(walk_start, walk_start_nr, compare_commits_by_gen);
275
276         /* remove STALE bit for now to allow walking through parents */
277         for (i = 0; i < walk_start_nr; i++)
278                 walk_start[i]->object.flags &= ~STALE;
279
280         /*
281          * Start walking from the highest generation. Hopefully, it will
282          * find all other items during the first-parent walk, and we can
283          * terminate early. Otherwise, we will do the same amount of work
284          * as before.
285          */
286         for (i = walk_start_nr - 1; i >= 0 && count_still_independent > 1; i--) {
287                 /* push the STALE bits up to min generation */
288                 struct commit_list *stack = NULL;
289
290                 commit_list_insert(walk_start[i], &stack);
291                 walk_start[i]->object.flags |= STALE;
292
293                 while (stack) {
294                         struct commit_list *parents;
295                         struct commit *c = stack->item;
296
297                         repo_parse_commit(r, c);
298
299                         if (c->object.flags & RESULT) {
300                                 c->object.flags &= ~RESULT;
301                                 if (--count_still_independent <= 1)
302                                         break;
303                                 if (oideq(&c->object.oid, &sorted[min_gen_pos]->object.oid)) {
304                                         while (min_gen_pos < cnt - 1 &&
305                                                (sorted[min_gen_pos]->object.flags & STALE))
306                                                 min_gen_pos++;
307                                         min_generation = commit_graph_generation(sorted[min_gen_pos]);
308                                 }
309                         }
310
311                         if (commit_graph_generation(c) < min_generation) {
312                                 pop_commit(&stack);
313                                 continue;
314                         }
315
316                         parents = c->parents;
317                         while (parents) {
318                                 if (!(parents->item->object.flags & STALE)) {
319                                         parents->item->object.flags |= STALE;
320                                         commit_list_insert(parents->item, &stack);
321                                         break;
322                                 }
323                                 parents = parents->next;
324                         }
325
326                         /* pop if all parents have been visited already */
327                         if (!parents)
328                                 pop_commit(&stack);
329                 }
330                 free_commit_list(stack);
331         }
332         free(sorted);
333
334         /* clear result */
335         for (i = 0; i < cnt; i++)
336                 array[i]->object.flags &= ~RESULT;
337
338         /* rearrange array */
339         for (i = count_non_stale = 0; i < cnt; i++) {
340                 if (!(array[i]->object.flags & STALE))
341                         array[count_non_stale++] = array[i];
342         }
343
344         /* clear marks */
345         clear_commit_marks_many(walk_start_nr, walk_start, STALE);
346         free(walk_start);
347
348         return count_non_stale;
349 }
350
351 static int remove_redundant(struct repository *r, struct commit **array, int cnt)
352 {
353         /*
354          * Some commit in the array may be an ancestor of
355          * another commit.  Move the independent commits to the
356          * beginning of 'array' and return their number. Callers
357          * should not rely upon the contents of 'array' after
358          * that number.
359          */
360         if (generation_numbers_enabled(r)) {
361                 int i;
362
363                 /*
364                  * If we have a single commit with finite generation
365                  * number, then the _with_gen algorithm is preferred.
366                  */
367                 for (i = 0; i < cnt; i++) {
368                         if (commit_graph_generation(array[i]) < GENERATION_NUMBER_INFINITY)
369                                 return remove_redundant_with_gen(r, array, cnt);
370                 }
371         }
372
373         return remove_redundant_no_gen(r, array, cnt);
374 }
375
376 static struct commit_list *get_merge_bases_many_0(struct repository *r,
377                                                   struct commit *one,
378                                                   int n,
379                                                   struct commit **twos,
380                                                   int cleanup)
381 {
382         struct commit_list *list;
383         struct commit **rslt;
384         struct commit_list *result;
385         int cnt, i;
386
387         result = merge_bases_many(r, one, n, twos);
388         for (i = 0; i < n; i++) {
389                 if (one == twos[i])
390                         return result;
391         }
392         if (!result || !result->next) {
393                 if (cleanup) {
394                         clear_commit_marks(one, all_flags);
395                         clear_commit_marks_many(n, twos, all_flags);
396                 }
397                 return result;
398         }
399
400         /* There are more than one */
401         cnt = commit_list_count(result);
402         rslt = xcalloc(cnt, sizeof(*rslt));
403         for (list = result, i = 0; list; list = list->next)
404                 rslt[i++] = list->item;
405         free_commit_list(result);
406
407         clear_commit_marks(one, all_flags);
408         clear_commit_marks_many(n, twos, all_flags);
409
410         cnt = remove_redundant(r, rslt, cnt);
411         result = NULL;
412         for (i = 0; i < cnt; i++)
413                 commit_list_insert_by_date(rslt[i], &result);
414         free(rslt);
415         return result;
416 }
417
418 struct commit_list *repo_get_merge_bases_many(struct repository *r,
419                                               struct commit *one,
420                                               int n,
421                                               struct commit **twos)
422 {
423         return get_merge_bases_many_0(r, one, n, twos, 1);
424 }
425
426 struct commit_list *repo_get_merge_bases_many_dirty(struct repository *r,
427                                                     struct commit *one,
428                                                     int n,
429                                                     struct commit **twos)
430 {
431         return get_merge_bases_many_0(r, one, n, twos, 0);
432 }
433
434 struct commit_list *repo_get_merge_bases(struct repository *r,
435                                          struct commit *one,
436                                          struct commit *two)
437 {
438         return get_merge_bases_many_0(r, one, 1, &two, 1);
439 }
440
441 /*
442  * Is "commit" a descendant of one of the elements on the "with_commit" list?
443  */
444 int repo_is_descendant_of(struct repository *r,
445                           struct commit *commit,
446                           struct commit_list *with_commit)
447 {
448         if (!with_commit)
449                 return 1;
450
451         if (generation_numbers_enabled(the_repository)) {
452                 struct commit_list *from_list = NULL;
453                 int result;
454                 commit_list_insert(commit, &from_list);
455                 result = can_all_from_reach(from_list, with_commit, 0);
456                 free_commit_list(from_list);
457                 return result;
458         } else {
459                 while (with_commit) {
460                         struct commit *other;
461
462                         other = with_commit->item;
463                         with_commit = with_commit->next;
464                         if (repo_in_merge_bases_many(r, other, 1, &commit))
465                                 return 1;
466                 }
467                 return 0;
468         }
469 }
470
471 /*
472  * Is "commit" an ancestor of one of the "references"?
473  */
474 int repo_in_merge_bases_many(struct repository *r, struct commit *commit,
475                              int nr_reference, struct commit **reference)
476 {
477         struct commit_list *bases;
478         int ret = 0, i;
479         timestamp_t generation, max_generation = GENERATION_NUMBER_ZERO;
480
481         if (repo_parse_commit(r, commit))
482                 return ret;
483         for (i = 0; i < nr_reference; i++) {
484                 if (repo_parse_commit(r, reference[i]))
485                         return ret;
486
487                 generation = commit_graph_generation(reference[i]);
488                 if (generation > max_generation)
489                         max_generation = generation;
490         }
491
492         generation = commit_graph_generation(commit);
493         if (generation > max_generation)
494                 return ret;
495
496         bases = paint_down_to_common(r, commit,
497                                      nr_reference, reference,
498                                      generation);
499         if (commit->object.flags & PARENT2)
500                 ret = 1;
501         clear_commit_marks(commit, all_flags);
502         clear_commit_marks_many(nr_reference, reference, all_flags);
503         free_commit_list(bases);
504         return ret;
505 }
506
507 /*
508  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
509  */
510 int repo_in_merge_bases(struct repository *r,
511                         struct commit *commit,
512                         struct commit *reference)
513 {
514         int res;
515         struct commit_list *list = NULL;
516         struct commit_list **next = &list;
517
518         next = commit_list_append(commit, next);
519         res = repo_is_descendant_of(r, reference, list);
520         free_commit_list(list);
521
522         return res;
523 }
524
525 struct commit_list *reduce_heads(struct commit_list *heads)
526 {
527         struct commit_list *p;
528         struct commit_list *result = NULL, **tail = &result;
529         struct commit **array;
530         int num_head, i;
531
532         if (!heads)
533                 return NULL;
534
535         /* Uniquify */
536         for (p = heads; p; p = p->next)
537                 p->item->object.flags &= ~STALE;
538         for (p = heads, num_head = 0; p; p = p->next) {
539                 if (p->item->object.flags & STALE)
540                         continue;
541                 p->item->object.flags |= STALE;
542                 num_head++;
543         }
544         array = xcalloc(num_head, sizeof(*array));
545         for (p = heads, i = 0; p; p = p->next) {
546                 if (p->item->object.flags & STALE) {
547                         array[i++] = p->item;
548                         p->item->object.flags &= ~STALE;
549                 }
550         }
551         num_head = remove_redundant(the_repository, array, num_head);
552         for (i = 0; i < num_head; i++)
553                 tail = &commit_list_insert(array[i], tail)->next;
554         free(array);
555         return result;
556 }
557
558 void reduce_heads_replace(struct commit_list **heads)
559 {
560         struct commit_list *result = reduce_heads(*heads);
561         free_commit_list(*heads);
562         *heads = result;
563 }
564
565 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
566 {
567         struct object *o;
568         struct commit *old_commit, *new_commit;
569         struct commit_list *old_commit_list = NULL;
570         int ret;
571
572         /*
573          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
574          * old_commit.  Otherwise we require --force.
575          */
576         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
577                       NULL, 0);
578         if (!o || o->type != OBJ_COMMIT)
579                 return 0;
580         old_commit = (struct commit *) o;
581
582         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
583                       NULL, 0);
584         if (!o || o->type != OBJ_COMMIT)
585                 return 0;
586         new_commit = (struct commit *) o;
587
588         if (parse_commit(new_commit) < 0)
589                 return 0;
590
591         commit_list_insert(old_commit, &old_commit_list);
592         ret = repo_is_descendant_of(the_repository,
593                                     new_commit, old_commit_list);
594         free_commit_list(old_commit_list);
595         return ret;
596 }
597
598 /*
599  * Mimicking the real stack, this stack lives on the heap, avoiding stack
600  * overflows.
601  *
602  * At each recursion step, the stack items points to the commits whose
603  * ancestors are to be inspected.
604  */
605 struct contains_stack {
606         int nr, alloc;
607         struct contains_stack_entry {
608                 struct commit *commit;
609                 struct commit_list *parents;
610         } *contains_stack;
611 };
612
613 static int in_commit_list(const struct commit_list *want, struct commit *c)
614 {
615         for (; want; want = want->next)
616                 if (oideq(&want->item->object.oid, &c->object.oid))
617                         return 1;
618         return 0;
619 }
620
621 /*
622  * Test whether the candidate is contained in the list.
623  * Do not recurse to find out, though, but return -1 if inconclusive.
624  */
625 static enum contains_result contains_test(struct commit *candidate,
626                                           const struct commit_list *want,
627                                           struct contains_cache *cache,
628                                           timestamp_t cutoff)
629 {
630         enum contains_result *cached = contains_cache_at(cache, candidate);
631
632         /* If we already have the answer cached, return that. */
633         if (*cached)
634                 return *cached;
635
636         /* or are we it? */
637         if (in_commit_list(want, candidate)) {
638                 *cached = CONTAINS_YES;
639                 return CONTAINS_YES;
640         }
641
642         /* Otherwise, we don't know; prepare to recurse */
643         parse_commit_or_die(candidate);
644
645         if (commit_graph_generation(candidate) < cutoff)
646                 return CONTAINS_NO;
647
648         return CONTAINS_UNKNOWN;
649 }
650
651 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
652 {
653         ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
654         contains_stack->contains_stack[contains_stack->nr].commit = candidate;
655         contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
656 }
657
658 static enum contains_result contains_tag_algo(struct commit *candidate,
659                                               const struct commit_list *want,
660                                               struct contains_cache *cache)
661 {
662         struct contains_stack contains_stack = { 0, 0, NULL };
663         enum contains_result result;
664         timestamp_t cutoff = GENERATION_NUMBER_INFINITY;
665         const struct commit_list *p;
666
667         for (p = want; p; p = p->next) {
668                 timestamp_t generation;
669                 struct commit *c = p->item;
670                 load_commit_graph_info(the_repository, c);
671                 generation = commit_graph_generation(c);
672                 if (generation < cutoff)
673                         cutoff = generation;
674         }
675
676         result = contains_test(candidate, want, cache, cutoff);
677         if (result != CONTAINS_UNKNOWN)
678                 return result;
679
680         push_to_contains_stack(candidate, &contains_stack);
681         while (contains_stack.nr) {
682                 struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
683                 struct commit *commit = entry->commit;
684                 struct commit_list *parents = entry->parents;
685
686                 if (!parents) {
687                         *contains_cache_at(cache, commit) = CONTAINS_NO;
688                         contains_stack.nr--;
689                 }
690                 /*
691                  * If we just popped the stack, parents->item has been marked,
692                  * therefore contains_test will return a meaningful yes/no.
693                  */
694                 else switch (contains_test(parents->item, want, cache, cutoff)) {
695                 case CONTAINS_YES:
696                         *contains_cache_at(cache, commit) = CONTAINS_YES;
697                         contains_stack.nr--;
698                         break;
699                 case CONTAINS_NO:
700                         entry->parents = parents->next;
701                         break;
702                 case CONTAINS_UNKNOWN:
703                         push_to_contains_stack(parents->item, &contains_stack);
704                         break;
705                 }
706         }
707         free(contains_stack.contains_stack);
708         return contains_test(candidate, want, cache, cutoff);
709 }
710
711 int commit_contains(struct ref_filter *filter, struct commit *commit,
712                     struct commit_list *list, struct contains_cache *cache)
713 {
714         if (filter->with_commit_tag_algo)
715                 return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
716         return repo_is_descendant_of(the_repository, commit, list);
717 }
718
719 int can_all_from_reach_with_flag(struct object_array *from,
720                                  unsigned int with_flag,
721                                  unsigned int assign_flag,
722                                  time_t min_commit_date,
723                                  timestamp_t min_generation)
724 {
725         struct commit **list = NULL;
726         int i;
727         int nr_commits;
728         int result = 1;
729
730         ALLOC_ARRAY(list, from->nr);
731         nr_commits = 0;
732         for (i = 0; i < from->nr; i++) {
733                 struct object *from_one = from->objects[i].item;
734
735                 if (!from_one || from_one->flags & assign_flag)
736                         continue;
737
738                 from_one = deref_tag(the_repository, from_one,
739                                      "a from object", 0);
740                 if (!from_one || from_one->type != OBJ_COMMIT) {
741                         /*
742                          * no way to tell if this is reachable by
743                          * looking at the ancestry chain alone, so
744                          * leave a note to ourselves not to worry about
745                          * this object anymore.
746                          */
747                         from->objects[i].item->flags |= assign_flag;
748                         continue;
749                 }
750
751                 list[nr_commits] = (struct commit *)from_one;
752                 if (parse_commit(list[nr_commits]) ||
753                     commit_graph_generation(list[nr_commits]) < min_generation) {
754                         result = 0;
755                         goto cleanup;
756                 }
757
758                 nr_commits++;
759         }
760
761         QSORT(list, nr_commits, compare_commits_by_gen);
762
763         for (i = 0; i < nr_commits; i++) {
764                 /* DFS from list[i] */
765                 struct commit_list *stack = NULL;
766
767                 list[i]->object.flags |= assign_flag;
768                 commit_list_insert(list[i], &stack);
769
770                 while (stack) {
771                         struct commit_list *parent;
772
773                         if (stack->item->object.flags & (with_flag | RESULT)) {
774                                 pop_commit(&stack);
775                                 if (stack)
776                                         stack->item->object.flags |= RESULT;
777                                 continue;
778                         }
779
780                         for (parent = stack->item->parents; parent; parent = parent->next) {
781                                 if (parent->item->object.flags & (with_flag | RESULT))
782                                         stack->item->object.flags |= RESULT;
783
784                                 if (!(parent->item->object.flags & assign_flag)) {
785                                         parent->item->object.flags |= assign_flag;
786
787                                         if (parse_commit(parent->item) ||
788                                             parent->item->date < min_commit_date ||
789                                             commit_graph_generation(parent->item) < min_generation)
790                                                 continue;
791
792                                         commit_list_insert(parent->item, &stack);
793                                         break;
794                                 }
795                         }
796
797                         if (!parent)
798                                 pop_commit(&stack);
799                 }
800
801                 if (!(list[i]->object.flags & (with_flag | RESULT))) {
802                         result = 0;
803                         goto cleanup;
804                 }
805         }
806
807 cleanup:
808         clear_commit_marks_many(nr_commits, list, RESULT | assign_flag);
809         free(list);
810
811         for (i = 0; i < from->nr; i++)
812                 from->objects[i].item->flags &= ~assign_flag;
813
814         return result;
815 }
816
817 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
818                        int cutoff_by_min_date)
819 {
820         struct object_array from_objs = OBJECT_ARRAY_INIT;
821         time_t min_commit_date = cutoff_by_min_date ? from->item->date : 0;
822         struct commit_list *from_iter = from, *to_iter = to;
823         int result;
824         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
825
826         while (from_iter) {
827                 add_object_array(&from_iter->item->object, NULL, &from_objs);
828
829                 if (!parse_commit(from_iter->item)) {
830                         timestamp_t generation;
831                         if (from_iter->item->date < min_commit_date)
832                                 min_commit_date = from_iter->item->date;
833
834                         generation = commit_graph_generation(from_iter->item);
835                         if (generation < min_generation)
836                                 min_generation = generation;
837                 }
838
839                 from_iter = from_iter->next;
840         }
841
842         while (to_iter) {
843                 if (!parse_commit(to_iter->item)) {
844                         timestamp_t generation;
845                         if (to_iter->item->date < min_commit_date)
846                                 min_commit_date = to_iter->item->date;
847
848                         generation = commit_graph_generation(to_iter->item);
849                         if (generation < min_generation)
850                                 min_generation = generation;
851                 }
852
853                 to_iter->item->object.flags |= PARENT2;
854
855                 to_iter = to_iter->next;
856         }
857
858         result = can_all_from_reach_with_flag(&from_objs, PARENT2, PARENT1,
859                                               min_commit_date, min_generation);
860
861         while (from) {
862                 clear_commit_marks(from->item, PARENT1);
863                 from = from->next;
864         }
865
866         while (to) {
867                 clear_commit_marks(to->item, PARENT2);
868                 to = to->next;
869         }
870
871         object_array_clear(&from_objs);
872         return result;
873 }
874
875 struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
876                                          struct commit **to, int nr_to,
877                                          unsigned int reachable_flag)
878 {
879         struct commit **item;
880         struct commit *current;
881         struct commit_list *found_commits = NULL;
882         struct commit **to_last = to + nr_to;
883         struct commit **from_last = from + nr_from;
884         timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
885         int num_to_find = 0;
886
887         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
888
889         for (item = to; item < to_last; item++) {
890                 timestamp_t generation;
891                 struct commit *c = *item;
892
893                 parse_commit(c);
894                 generation = commit_graph_generation(c);
895                 if (generation < min_generation)
896                         min_generation = generation;
897
898                 if (!(c->object.flags & PARENT1)) {
899                         c->object.flags |= PARENT1;
900                         num_to_find++;
901                 }
902         }
903
904         for (item = from; item < from_last; item++) {
905                 struct commit *c = *item;
906                 if (!(c->object.flags & PARENT2)) {
907                         c->object.flags |= PARENT2;
908                         parse_commit(c);
909
910                         prio_queue_put(&queue, *item);
911                 }
912         }
913
914         while (num_to_find && (current = prio_queue_get(&queue)) != NULL) {
915                 struct commit_list *parents;
916
917                 if (current->object.flags & PARENT1) {
918                         current->object.flags &= ~PARENT1;
919                         current->object.flags |= reachable_flag;
920                         commit_list_insert(current, &found_commits);
921                         num_to_find--;
922                 }
923
924                 for (parents = current->parents; parents; parents = parents->next) {
925                         struct commit *p = parents->item;
926
927                         parse_commit(p);
928
929                         if (commit_graph_generation(p) < min_generation)
930                                 continue;
931
932                         if (p->object.flags & PARENT2)
933                                 continue;
934
935                         p->object.flags |= PARENT2;
936                         prio_queue_put(&queue, p);
937                 }
938         }
939
940         clear_commit_marks_many(nr_to, to, PARENT1);
941         clear_commit_marks_many(nr_from, from, PARENT2);
942
943         return found_commits;
944 }