Merge branch 'ds/for-each-repo-noopfix' into maint
[git] / shallow.c
1 #include "cache.h"
2 #include "repository.h"
3 #include "tempfile.h"
4 #include "lockfile.h"
5 #include "object-store.h"
6 #include "commit.h"
7 #include "tag.h"
8 #include "pkt-line.h"
9 #include "remote.h"
10 #include "refs.h"
11 #include "oid-array.h"
12 #include "diff.h"
13 #include "revision.h"
14 #include "commit-slab.h"
15 #include "list-objects.h"
16 #include "commit-reach.h"
17 #include "shallow.h"
18
19 void set_alternate_shallow_file(struct repository *r, const char *path, int override)
20 {
21         if (r->parsed_objects->is_shallow != -1)
22                 BUG("is_repository_shallow must not be called before set_alternate_shallow_file");
23         if (r->parsed_objects->alternate_shallow_file && !override)
24                 return;
25         free(r->parsed_objects->alternate_shallow_file);
26         r->parsed_objects->alternate_shallow_file = xstrdup_or_null(path);
27 }
28
29 int register_shallow(struct repository *r, const struct object_id *oid)
30 {
31         struct commit_graft *graft =
32                 xmalloc(sizeof(struct commit_graft));
33         struct commit *commit = lookup_commit(the_repository, oid);
34
35         oidcpy(&graft->oid, oid);
36         graft->nr_parent = -1;
37         if (commit && commit->object.parsed)
38                 commit->parents = NULL;
39         return register_commit_graft(r, graft, 0);
40 }
41
42 int unregister_shallow(const struct object_id *oid)
43 {
44         int pos = commit_graft_pos(the_repository, oid->hash);
45         if (pos < 0)
46                 return -1;
47         if (pos + 1 < the_repository->parsed_objects->grafts_nr)
48                 MOVE_ARRAY(the_repository->parsed_objects->grafts + pos,
49                            the_repository->parsed_objects->grafts + pos + 1,
50                            the_repository->parsed_objects->grafts_nr - pos - 1);
51         the_repository->parsed_objects->grafts_nr--;
52         return 0;
53 }
54
55 int is_repository_shallow(struct repository *r)
56 {
57         FILE *fp;
58         char buf[1024];
59         const char *path = r->parsed_objects->alternate_shallow_file;
60
61         if (r->parsed_objects->is_shallow >= 0)
62                 return r->parsed_objects->is_shallow;
63
64         if (!path)
65                 path = git_path_shallow(r);
66         /*
67          * fetch-pack sets '--shallow-file ""' as an indicator that no
68          * shallow file should be used. We could just open it and it
69          * will likely fail. But let's do an explicit check instead.
70          */
71         if (!*path || (fp = fopen(path, "r")) == NULL) {
72                 stat_validity_clear(r->parsed_objects->shallow_stat);
73                 r->parsed_objects->is_shallow = 0;
74                 return r->parsed_objects->is_shallow;
75         }
76         stat_validity_update(r->parsed_objects->shallow_stat, fileno(fp));
77         r->parsed_objects->is_shallow = 1;
78
79         while (fgets(buf, sizeof(buf), fp)) {
80                 struct object_id oid;
81                 if (get_oid_hex(buf, &oid))
82                         die("bad shallow line: %s", buf);
83                 register_shallow(r, &oid);
84         }
85         fclose(fp);
86         return r->parsed_objects->is_shallow;
87 }
88
89 static void reset_repository_shallow(struct repository *r)
90 {
91         r->parsed_objects->is_shallow = -1;
92         stat_validity_clear(r->parsed_objects->shallow_stat);
93 }
94
95 int commit_shallow_file(struct repository *r, struct shallow_lock *lk)
96 {
97         int res = commit_lock_file(&lk->lock);
98         reset_repository_shallow(r);
99         return res;
100 }
101
102 void rollback_shallow_file(struct repository *r, struct shallow_lock *lk)
103 {
104         rollback_lock_file(&lk->lock);
105         reset_repository_shallow(r);
106 }
107
108 /*
109  * TODO: use "int" elemtype instead of "int *" when/if commit-slab
110  * supports a "valid" flag.
111  */
112 define_commit_slab(commit_depth, int *);
113 static void free_depth_in_slab(int **ptr)
114 {
115         FREE_AND_NULL(*ptr);
116 }
117 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
118                 int shallow_flag, int not_shallow_flag)
119 {
120         int i = 0, cur_depth = 0;
121         struct commit_list *result = NULL;
122         struct object_array stack = OBJECT_ARRAY_INIT;
123         struct commit *commit = NULL;
124         struct commit_graft *graft;
125         struct commit_depth depths;
126
127         init_commit_depth(&depths);
128         while (commit || i < heads->nr || stack.nr) {
129                 struct commit_list *p;
130                 if (!commit) {
131                         if (i < heads->nr) {
132                                 int **depth_slot;
133                                 commit = (struct commit *)
134                                         deref_tag(the_repository,
135                                                   heads->objects[i++].item,
136                                                   NULL, 0);
137                                 if (!commit || commit->object.type != OBJ_COMMIT) {
138                                         commit = NULL;
139                                         continue;
140                                 }
141                                 depth_slot = commit_depth_at(&depths, commit);
142                                 if (!*depth_slot)
143                                         *depth_slot = xmalloc(sizeof(int));
144                                 **depth_slot = 0;
145                                 cur_depth = 0;
146                         } else {
147                                 commit = (struct commit *)
148                                         object_array_pop(&stack);
149                                 cur_depth = **commit_depth_at(&depths, commit);
150                         }
151                 }
152                 parse_commit_or_die(commit);
153                 cur_depth++;
154                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
155                     (is_repository_shallow(the_repository) && !commit->parents &&
156                      (graft = lookup_commit_graft(the_repository, &commit->object.oid)) != NULL &&
157                      graft->nr_parent < 0)) {
158                         commit_list_insert(commit, &result);
159                         commit->object.flags |= shallow_flag;
160                         commit = NULL;
161                         continue;
162                 }
163                 commit->object.flags |= not_shallow_flag;
164                 for (p = commit->parents, commit = NULL; p; p = p->next) {
165                         int **depth_slot = commit_depth_at(&depths, p->item);
166                         if (!*depth_slot) {
167                                 *depth_slot = xmalloc(sizeof(int));
168                                 **depth_slot = cur_depth;
169                         } else {
170                                 if (cur_depth >= **depth_slot)
171                                         continue;
172                                 **depth_slot = cur_depth;
173                         }
174                         if (p->next)
175                                 add_object_array(&p->item->object,
176                                                 NULL, &stack);
177                         else {
178                                 commit = p->item;
179                                 cur_depth = **commit_depth_at(&depths, commit);
180                         }
181                 }
182         }
183         deep_clear_commit_depth(&depths, free_depth_in_slab);
184
185         return result;
186 }
187
188 static void show_commit(struct commit *commit, void *data)
189 {
190         commit_list_insert(commit, data);
191 }
192
193 /*
194  * Given rev-list arguments, run rev-list. All reachable commits
195  * except border ones are marked with not_shallow_flag. Border commits
196  * are marked with shallow_flag. The list of border/shallow commits
197  * are also returned.
198  */
199 struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av,
200                                                     int shallow_flag,
201                                                     int not_shallow_flag)
202 {
203         struct commit_list *result = NULL, *p;
204         struct commit_list *not_shallow_list = NULL;
205         struct rev_info revs;
206         int both_flags = shallow_flag | not_shallow_flag;
207
208         /*
209          * SHALLOW (excluded) and NOT_SHALLOW (included) should not be
210          * set at this point. But better be safe than sorry.
211          */
212         clear_object_flags(both_flags);
213
214         is_repository_shallow(the_repository); /* make sure shallows are read */
215
216         repo_init_revisions(the_repository, &revs, NULL);
217         save_commit_buffer = 0;
218         setup_revisions(ac, av, &revs, NULL);
219
220         if (prepare_revision_walk(&revs))
221                 die("revision walk setup failed");
222         traverse_commit_list(&revs, show_commit, NULL, &not_shallow_list);
223
224         if (!not_shallow_list)
225                 die("no commits selected for shallow requests");
226
227         /* Mark all reachable commits as NOT_SHALLOW */
228         for (p = not_shallow_list; p; p = p->next)
229                 p->item->object.flags |= not_shallow_flag;
230
231         /*
232          * mark border commits SHALLOW + NOT_SHALLOW.
233          * We cannot clear NOT_SHALLOW right now. Imagine border
234          * commit A is processed first, then commit B, whose parent is
235          * A, later. If NOT_SHALLOW on A is cleared at step 1, B
236          * itself is considered border at step 2, which is incorrect.
237          */
238         for (p = not_shallow_list; p; p = p->next) {
239                 struct commit *c = p->item;
240                 struct commit_list *parent;
241
242                 if (parse_commit(c))
243                         die("unable to parse commit %s",
244                             oid_to_hex(&c->object.oid));
245
246                 for (parent = c->parents; parent; parent = parent->next)
247                         if (!(parent->item->object.flags & not_shallow_flag)) {
248                                 c->object.flags |= shallow_flag;
249                                 commit_list_insert(c, &result);
250                                 break;
251                         }
252         }
253         free_commit_list(not_shallow_list);
254
255         /*
256          * Now we can clean up NOT_SHALLOW on border commits. Having
257          * both flags set can confuse the caller.
258          */
259         for (p = result; p; p = p->next) {
260                 struct object *o = &p->item->object;
261                 if ((o->flags & both_flags) == both_flags)
262                         o->flags &= ~not_shallow_flag;
263         }
264         return result;
265 }
266
267 static void check_shallow_file_for_update(struct repository *r)
268 {
269         if (r->parsed_objects->is_shallow == -1)
270                 BUG("shallow must be initialized by now");
271
272         if (!stat_validity_check(r->parsed_objects->shallow_stat,
273                                  git_path_shallow(r)))
274                 die("shallow file has changed since we read it");
275 }
276
277 #define SEEN_ONLY 1
278 #define VERBOSE   2
279 #define QUICK 4
280
281 struct write_shallow_data {
282         struct strbuf *out;
283         int use_pack_protocol;
284         int count;
285         unsigned flags;
286 };
287
288 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
289 {
290         struct write_shallow_data *data = cb_data;
291         const char *hex = oid_to_hex(&graft->oid);
292         if (graft->nr_parent != -1)
293                 return 0;
294         if (data->flags & QUICK) {
295                 if (!has_object_file(&graft->oid))
296                         return 0;
297         } else if (data->flags & SEEN_ONLY) {
298                 struct commit *c = lookup_commit(the_repository, &graft->oid);
299                 if (!c || !(c->object.flags & SEEN)) {
300                         if (data->flags & VERBOSE)
301                                 printf("Removing %s from .git/shallow\n",
302                                        oid_to_hex(&c->object.oid));
303                         return 0;
304                 }
305         }
306         data->count++;
307         if (data->use_pack_protocol)
308                 packet_buf_write(data->out, "shallow %s", hex);
309         else {
310                 strbuf_addstr(data->out, hex);
311                 strbuf_addch(data->out, '\n');
312         }
313         return 0;
314 }
315
316 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
317                                    const struct oid_array *extra,
318                                    unsigned flags)
319 {
320         struct write_shallow_data data;
321         int i;
322         data.out = out;
323         data.use_pack_protocol = use_pack_protocol;
324         data.count = 0;
325         data.flags = flags;
326         for_each_commit_graft(write_one_shallow, &data);
327         if (!extra)
328                 return data.count;
329         for (i = 0; i < extra->nr; i++) {
330                 strbuf_addstr(out, oid_to_hex(extra->oid + i));
331                 strbuf_addch(out, '\n');
332                 data.count++;
333         }
334         return data.count;
335 }
336
337 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
338                           const struct oid_array *extra)
339 {
340         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
341 }
342
343 const char *setup_temporary_shallow(const struct oid_array *extra)
344 {
345         struct tempfile *temp;
346         struct strbuf sb = STRBUF_INIT;
347
348         if (write_shallow_commits(&sb, 0, extra)) {
349                 temp = xmks_tempfile(git_path("shallow_XXXXXX"));
350
351                 if (write_in_full(temp->fd, sb.buf, sb.len) < 0 ||
352                     close_tempfile_gently(temp) < 0)
353                         die_errno("failed to write to %s",
354                                   get_tempfile_path(temp));
355                 strbuf_release(&sb);
356                 return get_tempfile_path(temp);
357         }
358         /*
359          * is_repository_shallow() sees empty string as "no shallow
360          * file".
361          */
362         return "";
363 }
364
365 void setup_alternate_shallow(struct shallow_lock *shallow_lock,
366                              const char **alternate_shallow_file,
367                              const struct oid_array *extra)
368 {
369         struct strbuf sb = STRBUF_INIT;
370         int fd;
371
372         fd = hold_lock_file_for_update(&shallow_lock->lock,
373                                        git_path_shallow(the_repository),
374                                        LOCK_DIE_ON_ERROR);
375         check_shallow_file_for_update(the_repository);
376         if (write_shallow_commits(&sb, 0, extra)) {
377                 if (write_in_full(fd, sb.buf, sb.len) < 0)
378                         die_errno("failed to write to %s",
379                                   get_lock_file_path(&shallow_lock->lock));
380                 *alternate_shallow_file = get_lock_file_path(&shallow_lock->lock);
381         } else
382                 /*
383                  * is_repository_shallow() sees empty string as "no
384                  * shallow file".
385                  */
386                 *alternate_shallow_file = "";
387         strbuf_release(&sb);
388 }
389
390 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
391 {
392         int fd = *(int *)cb;
393         if (graft->nr_parent == -1)
394                 packet_write_fmt(fd, "shallow %s\n", oid_to_hex(&graft->oid));
395         return 0;
396 }
397
398 void advertise_shallow_grafts(int fd)
399 {
400         if (!is_repository_shallow(the_repository))
401                 return;
402         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
403 }
404
405 /*
406  * mark_reachable_objects() should have been run prior to this and all
407  * reachable commits marked as "SEEN", except when quick_prune is non-zero,
408  * in which case lines are excised from the shallow file if they refer to
409  * commits that do not exist (any longer).
410  */
411 void prune_shallow(unsigned options)
412 {
413         struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
414         struct strbuf sb = STRBUF_INIT;
415         unsigned flags = SEEN_ONLY;
416         int fd;
417
418         if (options & PRUNE_QUICK)
419                 flags |= QUICK;
420
421         if (options & PRUNE_SHOW_ONLY) {
422                 flags |= VERBOSE;
423                 write_shallow_commits_1(&sb, 0, NULL, flags);
424                 strbuf_release(&sb);
425                 return;
426         }
427         fd = hold_lock_file_for_update(&shallow_lock.lock,
428                                        git_path_shallow(the_repository),
429                                        LOCK_DIE_ON_ERROR);
430         check_shallow_file_for_update(the_repository);
431         if (write_shallow_commits_1(&sb, 0, NULL, flags)) {
432                 if (write_in_full(fd, sb.buf, sb.len) < 0)
433                         die_errno("failed to write to %s",
434                                   get_lock_file_path(&shallow_lock.lock));
435                 commit_shallow_file(the_repository, &shallow_lock);
436         } else {
437                 unlink(git_path_shallow(the_repository));
438                 rollback_shallow_file(the_repository, &shallow_lock);
439         }
440         strbuf_release(&sb);
441 }
442
443 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
444
445 /*
446  * Step 1, split sender shallow commits into "ours" and "theirs"
447  * Step 2, clean "ours" based on .git/shallow
448  */
449 void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa)
450 {
451         int i;
452         trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
453         memset(info, 0, sizeof(*info));
454         info->shallow = sa;
455         if (!sa)
456                 return;
457         ALLOC_ARRAY(info->ours, sa->nr);
458         ALLOC_ARRAY(info->theirs, sa->nr);
459         for (i = 0; i < sa->nr; i++) {
460                 if (has_object_file(sa->oid + i)) {
461                         struct commit_graft *graft;
462                         graft = lookup_commit_graft(the_repository,
463                                                     &sa->oid[i]);
464                         if (graft && graft->nr_parent < 0)
465                                 continue;
466                         info->ours[info->nr_ours++] = i;
467                 } else
468                         info->theirs[info->nr_theirs++] = i;
469         }
470 }
471
472 void clear_shallow_info(struct shallow_info *info)
473 {
474         free(info->ours);
475         free(info->theirs);
476 }
477
478 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
479
480 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
481 {
482         struct object_id *oid = info->shallow->oid;
483         int i, dst;
484         trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
485         for (i = dst = 0; i < info->nr_theirs; i++) {
486                 if (i != dst)
487                         info->theirs[dst] = info->theirs[i];
488                 if (has_object_file(oid + info->theirs[i]))
489                         dst++;
490         }
491         info->nr_theirs = dst;
492 }
493
494 define_commit_slab(ref_bitmap, uint32_t *);
495
496 #define POOL_SIZE (512 * 1024)
497
498 struct paint_info {
499         struct ref_bitmap ref_bitmap;
500         unsigned nr_bits;
501         char **pools;
502         char *free, *end;
503         unsigned pool_count;
504 };
505
506 static uint32_t *paint_alloc(struct paint_info *info)
507 {
508         unsigned nr = DIV_ROUND_UP(info->nr_bits, 32);
509         unsigned size = nr * sizeof(uint32_t);
510         void *p;
511         if (!info->pool_count || size > info->end - info->free) {
512                 if (size > POOL_SIZE)
513                         BUG("pool size too small for %d in paint_alloc()",
514                             size);
515                 info->pool_count++;
516                 REALLOC_ARRAY(info->pools, info->pool_count);
517                 info->free = xmalloc(POOL_SIZE);
518                 info->pools[info->pool_count - 1] = info->free;
519                 info->end = info->free + POOL_SIZE;
520         }
521         p = info->free;
522         info->free += size;
523         return p;
524 }
525
526 /*
527  * Given a commit SHA-1, walk down to parents until either SEEN,
528  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
529  * all walked commits.
530  */
531 static void paint_down(struct paint_info *info, const struct object_id *oid,
532                        unsigned int id)
533 {
534         unsigned int i, nr;
535         struct commit_list *head = NULL;
536         int bitmap_nr = DIV_ROUND_UP(info->nr_bits, 32);
537         size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
538         struct commit *c = lookup_commit_reference_gently(the_repository, oid,
539                                                           1);
540         uint32_t *tmp; /* to be freed before return */
541         uint32_t *bitmap;
542
543         if (!c)
544                 return;
545
546         tmp = xmalloc(bitmap_size);
547         bitmap = paint_alloc(info);
548         memset(bitmap, 0, bitmap_size);
549         bitmap[id / 32] |= (1U << (id % 32));
550         commit_list_insert(c, &head);
551         while (head) {
552                 struct commit_list *p;
553                 struct commit *c = pop_commit(&head);
554                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
555
556                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
557                 if (c->object.flags & (SEEN | UNINTERESTING))
558                         continue;
559                 else
560                         c->object.flags |= SEEN;
561
562                 if (*refs == NULL)
563                         *refs = bitmap;
564                 else {
565                         memcpy(tmp, *refs, bitmap_size);
566                         for (i = 0; i < bitmap_nr; i++)
567                                 tmp[i] |= bitmap[i];
568                         if (memcmp(tmp, *refs, bitmap_size)) {
569                                 *refs = paint_alloc(info);
570                                 memcpy(*refs, tmp, bitmap_size);
571                         }
572                 }
573
574                 if (c->object.flags & BOTTOM)
575                         continue;
576
577                 if (parse_commit(c))
578                         die("unable to parse commit %s",
579                             oid_to_hex(&c->object.oid));
580
581                 for (p = c->parents; p; p = p->next) {
582                         if (p->item->object.flags & SEEN)
583                                 continue;
584                         commit_list_insert(p->item, &head);
585                 }
586         }
587
588         nr = get_max_object_index();
589         for (i = 0; i < nr; i++) {
590                 struct object *o = get_indexed_object(i);
591                 if (o && o->type == OBJ_COMMIT)
592                         o->flags &= ~SEEN;
593         }
594
595         free(tmp);
596 }
597
598 static int mark_uninteresting(const char *refname, const struct object_id *oid,
599                               int flags, void *cb_data)
600 {
601         struct commit *commit = lookup_commit_reference_gently(the_repository,
602                                                                oid, 1);
603         if (!commit)
604                 return 0;
605         commit->object.flags |= UNINTERESTING;
606         mark_parents_uninteresting(commit);
607         return 0;
608 }
609
610 static void post_assign_shallow(struct shallow_info *info,
611                                 struct ref_bitmap *ref_bitmap,
612                                 int *ref_status);
613 /*
614  * Step 6(+7), associate shallow commits with new refs
615  *
616  * info->ref must be initialized before calling this function.
617  *
618  * If used is not NULL, it's an array of info->shallow->nr
619  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
620  * m-th shallow commit from info->shallow.
621  *
622  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
623  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
624  * the ref needs some shallow commits from either info->ours or
625  * info->theirs.
626  */
627 void assign_shallow_commits_to_refs(struct shallow_info *info,
628                                     uint32_t **used, int *ref_status)
629 {
630         struct object_id *oid = info->shallow->oid;
631         struct oid_array *ref = info->ref;
632         unsigned int i, nr;
633         int *shallow, nr_shallow = 0;
634         struct paint_info pi;
635
636         trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
637         ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs);
638         for (i = 0; i < info->nr_ours; i++)
639                 shallow[nr_shallow++] = info->ours[i];
640         for (i = 0; i < info->nr_theirs; i++)
641                 shallow[nr_shallow++] = info->theirs[i];
642
643         /*
644          * Prepare the commit graph to track what refs can reach what
645          * (new) shallow commits.
646          */
647         nr = get_max_object_index();
648         for (i = 0; i < nr; i++) {
649                 struct object *o = get_indexed_object(i);
650                 if (!o || o->type != OBJ_COMMIT)
651                         continue;
652
653                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
654         }
655
656         memset(&pi, 0, sizeof(pi));
657         init_ref_bitmap(&pi.ref_bitmap);
658         pi.nr_bits = ref->nr;
659
660         /*
661          * "--not --all" to cut short the traversal if new refs
662          * connect to old refs. If not (e.g. force ref updates) it'll
663          * have to go down to the current shallow commits.
664          */
665         head_ref(mark_uninteresting, NULL);
666         for_each_ref(mark_uninteresting, NULL);
667
668         /* Mark potential bottoms so we won't go out of bound */
669         for (i = 0; i < nr_shallow; i++) {
670                 struct commit *c = lookup_commit(the_repository,
671                                                  &oid[shallow[i]]);
672                 c->object.flags |= BOTTOM;
673         }
674
675         for (i = 0; i < ref->nr; i++)
676                 paint_down(&pi, ref->oid + i, i);
677
678         if (used) {
679                 int bitmap_size = DIV_ROUND_UP(pi.nr_bits, 32) * sizeof(uint32_t);
680                 memset(used, 0, sizeof(*used) * info->shallow->nr);
681                 for (i = 0; i < nr_shallow; i++) {
682                         const struct commit *c = lookup_commit(the_repository,
683                                                                &oid[shallow[i]]);
684                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
685                         if (*map)
686                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
687                 }
688                 /*
689                  * unreachable shallow commits are not removed from
690                  * "ours" and "theirs". The user is supposed to run
691                  * step 7 on every ref separately and not trust "ours"
692                  * and "theirs" any more.
693                  */
694         } else
695                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
696
697         clear_ref_bitmap(&pi.ref_bitmap);
698         for (i = 0; i < pi.pool_count; i++)
699                 free(pi.pools[i]);
700         free(pi.pools);
701         free(shallow);
702 }
703
704 struct commit_array {
705         struct commit **commits;
706         int nr, alloc;
707 };
708
709 static int add_ref(const char *refname, const struct object_id *oid,
710                    int flags, void *cb_data)
711 {
712         struct commit_array *ca = cb_data;
713         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
714         ca->commits[ca->nr] = lookup_commit_reference_gently(the_repository,
715                                                              oid, 1);
716         if (ca->commits[ca->nr])
717                 ca->nr++;
718         return 0;
719 }
720
721 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
722 {
723         unsigned int i;
724         if (!ref_status)
725                 return;
726         for (i = 0; i < nr; i++)
727                 if (bitmap[i / 32] & (1U << (i % 32)))
728                         ref_status[i]++;
729 }
730
731 /*
732  * Step 7, reachability test on "ours" at commit level
733  */
734 static void post_assign_shallow(struct shallow_info *info,
735                                 struct ref_bitmap *ref_bitmap,
736                                 int *ref_status)
737 {
738         struct object_id *oid = info->shallow->oid;
739         struct commit *c;
740         uint32_t **bitmap;
741         int dst, i, j;
742         int bitmap_nr = DIV_ROUND_UP(info->ref->nr, 32);
743         struct commit_array ca;
744
745         trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
746         if (ref_status)
747                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
748
749         /* Remove unreachable shallow commits from "theirs" */
750         for (i = dst = 0; i < info->nr_theirs; i++) {
751                 if (i != dst)
752                         info->theirs[dst] = info->theirs[i];
753                 c = lookup_commit(the_repository, &oid[info->theirs[i]]);
754                 bitmap = ref_bitmap_at(ref_bitmap, c);
755                 if (!*bitmap)
756                         continue;
757                 for (j = 0; j < bitmap_nr; j++)
758                         if (bitmap[0][j]) {
759                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
760                                 dst++;
761                                 break;
762                         }
763         }
764         info->nr_theirs = dst;
765
766         memset(&ca, 0, sizeof(ca));
767         head_ref(add_ref, &ca);
768         for_each_ref(add_ref, &ca);
769
770         /* Remove unreachable shallow commits from "ours" */
771         for (i = dst = 0; i < info->nr_ours; i++) {
772                 if (i != dst)
773                         info->ours[dst] = info->ours[i];
774                 c = lookup_commit(the_repository, &oid[info->ours[i]]);
775                 bitmap = ref_bitmap_at(ref_bitmap, c);
776                 if (!*bitmap)
777                         continue;
778                 for (j = 0; j < bitmap_nr; j++)
779                         if (bitmap[0][j] &&
780                             /* Step 7, reachability test at commit level */
781                             !in_merge_bases_many(c, ca.nr, ca.commits)) {
782                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
783                                 dst++;
784                                 break;
785                         }
786         }
787         info->nr_ours = dst;
788
789         free(ca.commits);
790 }
791
792 /* (Delayed) step 7, reachability test at commit level */
793 int delayed_reachability_test(struct shallow_info *si, int c)
794 {
795         if (si->need_reachability_test[c]) {
796                 struct commit *commit = lookup_commit(the_repository,
797                                                       &si->shallow->oid[c]);
798
799                 if (!si->commits) {
800                         struct commit_array ca;
801
802                         memset(&ca, 0, sizeof(ca));
803                         head_ref(add_ref, &ca);
804                         for_each_ref(add_ref, &ca);
805                         si->commits = ca.commits;
806                         si->nr_commits = ca.nr;
807                 }
808
809                 si->reachable[c] = in_merge_bases_many(commit,
810                                                        si->nr_commits,
811                                                        si->commits);
812                 si->need_reachability_test[c] = 0;
813         }
814         return si->reachable[c];
815 }