Merge branch 'sr/gpg-interface-stop-at-the-end'
[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 "sha1-array.h"
12 #include "diff.h"
13 #include "revision.h"
14 #include "commit-slab.h"
15 #include "revision.h"
16 #include "list-objects.h"
17 #include "commit-slab.h"
18 #include "repository.h"
19 #include "commit-reach.h"
20
21 void set_alternate_shallow_file(struct repository *r, const char *path, int override)
22 {
23         if (r->parsed_objects->is_shallow != -1)
24                 BUG("is_repository_shallow must not be called before set_alternate_shallow_file");
25         if (r->parsed_objects->alternate_shallow_file && !override)
26                 return;
27         free(r->parsed_objects->alternate_shallow_file);
28         r->parsed_objects->alternate_shallow_file = xstrdup_or_null(path);
29 }
30
31 int register_shallow(struct repository *r, const struct object_id *oid)
32 {
33         struct commit_graft *graft =
34                 xmalloc(sizeof(struct commit_graft));
35         struct commit *commit = lookup_commit(the_repository, oid);
36
37         oidcpy(&graft->oid, oid);
38         graft->nr_parent = -1;
39         if (commit && commit->object.parsed)
40                 commit->parents = NULL;
41         return register_commit_graft(r, graft, 0);
42 }
43
44 int is_repository_shallow(struct repository *r)
45 {
46         /*
47          * NEEDSWORK: This function updates
48          * r->parsed_objects->{is_shallow,shallow_stat} as a side effect but
49          * there is no corresponding function to clear them when the shallow
50          * file is updated.
51          */
52
53         FILE *fp;
54         char buf[1024];
55         const char *path = r->parsed_objects->alternate_shallow_file;
56
57         if (r->parsed_objects->is_shallow >= 0)
58                 return r->parsed_objects->is_shallow;
59
60         if (!path)
61                 path = git_path_shallow(r);
62         /*
63          * fetch-pack sets '--shallow-file ""' as an indicator that no
64          * shallow file should be used. We could just open it and it
65          * will likely fail. But let's do an explicit check instead.
66          */
67         if (!*path || (fp = fopen(path, "r")) == NULL) {
68                 stat_validity_clear(r->parsed_objects->shallow_stat);
69                 r->parsed_objects->is_shallow = 0;
70                 return r->parsed_objects->is_shallow;
71         }
72         stat_validity_update(r->parsed_objects->shallow_stat, fileno(fp));
73         r->parsed_objects->is_shallow = 1;
74
75         while (fgets(buf, sizeof(buf), fp)) {
76                 struct object_id oid;
77                 if (get_oid_hex(buf, &oid))
78                         die("bad shallow line: %s", buf);
79                 register_shallow(r, &oid);
80         }
81         fclose(fp);
82         return r->parsed_objects->is_shallow;
83 }
84
85 /*
86  * TODO: use "int" elemtype instead of "int *" when/if commit-slab
87  * supports a "valid" flag.
88  */
89 define_commit_slab(commit_depth, int *);
90 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
91                 int shallow_flag, int not_shallow_flag)
92 {
93         int i = 0, cur_depth = 0;
94         struct commit_list *result = NULL;
95         struct object_array stack = OBJECT_ARRAY_INIT;
96         struct commit *commit = NULL;
97         struct commit_graft *graft;
98         struct commit_depth depths;
99
100         init_commit_depth(&depths);
101         while (commit || i < heads->nr || stack.nr) {
102                 struct commit_list *p;
103                 if (!commit) {
104                         if (i < heads->nr) {
105                                 int **depth_slot;
106                                 commit = (struct commit *)
107                                         deref_tag(the_repository,
108                                                   heads->objects[i++].item,
109                                                   NULL, 0);
110                                 if (!commit || commit->object.type != OBJ_COMMIT) {
111                                         commit = NULL;
112                                         continue;
113                                 }
114                                 depth_slot = commit_depth_at(&depths, commit);
115                                 if (!*depth_slot)
116                                         *depth_slot = xmalloc(sizeof(int));
117                                 **depth_slot = 0;
118                                 cur_depth = 0;
119                         } else {
120                                 commit = (struct commit *)
121                                         object_array_pop(&stack);
122                                 cur_depth = **commit_depth_at(&depths, commit);
123                         }
124                 }
125                 parse_commit_or_die(commit);
126                 cur_depth++;
127                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
128                     (is_repository_shallow(the_repository) && !commit->parents &&
129                      (graft = lookup_commit_graft(the_repository, &commit->object.oid)) != NULL &&
130                      graft->nr_parent < 0)) {
131                         commit_list_insert(commit, &result);
132                         commit->object.flags |= shallow_flag;
133                         commit = NULL;
134                         continue;
135                 }
136                 commit->object.flags |= not_shallow_flag;
137                 for (p = commit->parents, commit = NULL; p; p = p->next) {
138                         int **depth_slot = commit_depth_at(&depths, p->item);
139                         if (!*depth_slot) {
140                                 *depth_slot = xmalloc(sizeof(int));
141                                 **depth_slot = cur_depth;
142                         } else {
143                                 if (cur_depth >= **depth_slot)
144                                         continue;
145                                 **depth_slot = cur_depth;
146                         }
147                         if (p->next)
148                                 add_object_array(&p->item->object,
149                                                 NULL, &stack);
150                         else {
151                                 commit = p->item;
152                                 cur_depth = **commit_depth_at(&depths, commit);
153                         }
154                 }
155         }
156         for (i = 0; i < depths.slab_count; i++) {
157                 int j;
158
159                 for (j = 0; j < depths.slab_size; j++)
160                         free(depths.slab[i][j]);
161         }
162         clear_commit_depth(&depths);
163
164         return result;
165 }
166
167 static void show_commit(struct commit *commit, void *data)
168 {
169         commit_list_insert(commit, data);
170 }
171
172 /*
173  * Given rev-list arguments, run rev-list. All reachable commits
174  * except border ones are marked with not_shallow_flag. Border commits
175  * are marked with shallow_flag. The list of border/shallow commits
176  * are also returned.
177  */
178 struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av,
179                                                     int shallow_flag,
180                                                     int not_shallow_flag)
181 {
182         struct commit_list *result = NULL, *p;
183         struct commit_list *not_shallow_list = NULL;
184         struct rev_info revs;
185         int both_flags = shallow_flag | not_shallow_flag;
186
187         /*
188          * SHALLOW (excluded) and NOT_SHALLOW (included) should not be
189          * set at this point. But better be safe than sorry.
190          */
191         clear_object_flags(both_flags);
192
193         is_repository_shallow(the_repository); /* make sure shallows are read */
194
195         repo_init_revisions(the_repository, &revs, NULL);
196         save_commit_buffer = 0;
197         setup_revisions(ac, av, &revs, NULL);
198
199         if (prepare_revision_walk(&revs))
200                 die("revision walk setup failed");
201         traverse_commit_list(&revs, show_commit, NULL, &not_shallow_list);
202
203         if (!not_shallow_list)
204                 die("no commits selected for shallow requests");
205
206         /* Mark all reachable commits as NOT_SHALLOW */
207         for (p = not_shallow_list; p; p = p->next)
208                 p->item->object.flags |= not_shallow_flag;
209
210         /*
211          * mark border commits SHALLOW + NOT_SHALLOW.
212          * We cannot clear NOT_SHALLOW right now. Imagine border
213          * commit A is processed first, then commit B, whose parent is
214          * A, later. If NOT_SHALLOW on A is cleared at step 1, B
215          * itself is considered border at step 2, which is incorrect.
216          */
217         for (p = not_shallow_list; p; p = p->next) {
218                 struct commit *c = p->item;
219                 struct commit_list *parent;
220
221                 if (parse_commit(c))
222                         die("unable to parse commit %s",
223                             oid_to_hex(&c->object.oid));
224
225                 for (parent = c->parents; parent; parent = parent->next)
226                         if (!(parent->item->object.flags & not_shallow_flag)) {
227                                 c->object.flags |= shallow_flag;
228                                 commit_list_insert(c, &result);
229                                 break;
230                         }
231         }
232         free_commit_list(not_shallow_list);
233
234         /*
235          * Now we can clean up NOT_SHALLOW on border commits. Having
236          * both flags set can confuse the caller.
237          */
238         for (p = result; p; p = p->next) {
239                 struct object *o = &p->item->object;
240                 if ((o->flags & both_flags) == both_flags)
241                         o->flags &= ~not_shallow_flag;
242         }
243         return result;
244 }
245
246 static void check_shallow_file_for_update(struct repository *r)
247 {
248         if (r->parsed_objects->is_shallow == -1)
249                 BUG("shallow must be initialized by now");
250
251         if (!stat_validity_check(r->parsed_objects->shallow_stat,
252                                  git_path_shallow(r)))
253                 die("shallow file has changed since we read it");
254 }
255
256 #define SEEN_ONLY 1
257 #define VERBOSE   2
258 #define QUICK 4
259
260 struct write_shallow_data {
261         struct strbuf *out;
262         int use_pack_protocol;
263         int count;
264         unsigned flags;
265 };
266
267 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
268 {
269         struct write_shallow_data *data = cb_data;
270         const char *hex = oid_to_hex(&graft->oid);
271         if (graft->nr_parent != -1)
272                 return 0;
273         if (data->flags & QUICK) {
274                 if (!has_object_file(&graft->oid))
275                         return 0;
276         } else if (data->flags & SEEN_ONLY) {
277                 struct commit *c = lookup_commit(the_repository, &graft->oid);
278                 if (!c || !(c->object.flags & SEEN)) {
279                         if (data->flags & VERBOSE)
280                                 printf("Removing %s from .git/shallow\n",
281                                        oid_to_hex(&c->object.oid));
282                         return 0;
283                 }
284         }
285         data->count++;
286         if (data->use_pack_protocol)
287                 packet_buf_write(data->out, "shallow %s", hex);
288         else {
289                 strbuf_addstr(data->out, hex);
290                 strbuf_addch(data->out, '\n');
291         }
292         return 0;
293 }
294
295 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
296                                    const struct oid_array *extra,
297                                    unsigned flags)
298 {
299         struct write_shallow_data data;
300         int i;
301         data.out = out;
302         data.use_pack_protocol = use_pack_protocol;
303         data.count = 0;
304         data.flags = flags;
305         for_each_commit_graft(write_one_shallow, &data);
306         if (!extra)
307                 return data.count;
308         for (i = 0; i < extra->nr; i++) {
309                 strbuf_addstr(out, oid_to_hex(extra->oid + i));
310                 strbuf_addch(out, '\n');
311                 data.count++;
312         }
313         return data.count;
314 }
315
316 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
317                           const struct oid_array *extra)
318 {
319         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
320 }
321
322 const char *setup_temporary_shallow(const struct oid_array *extra)
323 {
324         struct tempfile *temp;
325         struct strbuf sb = STRBUF_INIT;
326
327         if (write_shallow_commits(&sb, 0, extra)) {
328                 temp = xmks_tempfile(git_path("shallow_XXXXXX"));
329
330                 if (write_in_full(temp->fd, sb.buf, sb.len) < 0 ||
331                     close_tempfile_gently(temp) < 0)
332                         die_errno("failed to write to %s",
333                                   get_tempfile_path(temp));
334                 strbuf_release(&sb);
335                 return get_tempfile_path(temp);
336         }
337         /*
338          * is_repository_shallow() sees empty string as "no shallow
339          * file".
340          */
341         return "";
342 }
343
344 void setup_alternate_shallow(struct lock_file *shallow_lock,
345                              const char **alternate_shallow_file,
346                              const struct oid_array *extra)
347 {
348         struct strbuf sb = STRBUF_INIT;
349         int fd;
350
351         fd = hold_lock_file_for_update(shallow_lock,
352                                        git_path_shallow(the_repository),
353                                        LOCK_DIE_ON_ERROR);
354         check_shallow_file_for_update(the_repository);
355         if (write_shallow_commits(&sb, 0, extra)) {
356                 if (write_in_full(fd, sb.buf, sb.len) < 0)
357                         die_errno("failed to write to %s",
358                                   get_lock_file_path(shallow_lock));
359                 *alternate_shallow_file = get_lock_file_path(shallow_lock);
360         } else
361                 /*
362                  * is_repository_shallow() sees empty string as "no
363                  * shallow file".
364                  */
365                 *alternate_shallow_file = "";
366         strbuf_release(&sb);
367 }
368
369 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
370 {
371         int fd = *(int *)cb;
372         if (graft->nr_parent == -1)
373                 packet_write_fmt(fd, "shallow %s\n", oid_to_hex(&graft->oid));
374         return 0;
375 }
376
377 void advertise_shallow_grafts(int fd)
378 {
379         if (!is_repository_shallow(the_repository))
380                 return;
381         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
382 }
383
384 /*
385  * mark_reachable_objects() should have been run prior to this and all
386  * reachable commits marked as "SEEN", except when quick_prune is non-zero,
387  * in which case lines are excised from the shallow file if they refer to
388  * commits that do not exist (any longer).
389  */
390 void prune_shallow(unsigned options)
391 {
392         struct lock_file shallow_lock = LOCK_INIT;
393         struct strbuf sb = STRBUF_INIT;
394         unsigned flags = SEEN_ONLY;
395         int fd;
396
397         if (options & PRUNE_QUICK)
398                 flags |= QUICK;
399
400         if (options & PRUNE_SHOW_ONLY) {
401                 flags |= VERBOSE;
402                 write_shallow_commits_1(&sb, 0, NULL, flags);
403                 strbuf_release(&sb);
404                 return;
405         }
406         fd = hold_lock_file_for_update(&shallow_lock,
407                                        git_path_shallow(the_repository),
408                                        LOCK_DIE_ON_ERROR);
409         check_shallow_file_for_update(the_repository);
410         if (write_shallow_commits_1(&sb, 0, NULL, flags)) {
411                 if (write_in_full(fd, sb.buf, sb.len) < 0)
412                         die_errno("failed to write to %s",
413                                   get_lock_file_path(&shallow_lock));
414                 commit_lock_file(&shallow_lock);
415         } else {
416                 unlink(git_path_shallow(the_repository));
417                 rollback_lock_file(&shallow_lock);
418         }
419         strbuf_release(&sb);
420 }
421
422 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
423
424 /*
425  * Step 1, split sender shallow commits into "ours" and "theirs"
426  * Step 2, clean "ours" based on .git/shallow
427  */
428 void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa)
429 {
430         int i;
431         trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
432         memset(info, 0, sizeof(*info));
433         info->shallow = sa;
434         if (!sa)
435                 return;
436         ALLOC_ARRAY(info->ours, sa->nr);
437         ALLOC_ARRAY(info->theirs, sa->nr);
438         for (i = 0; i < sa->nr; i++) {
439                 if (has_object_file(sa->oid + i)) {
440                         struct commit_graft *graft;
441                         graft = lookup_commit_graft(the_repository,
442                                                     &sa->oid[i]);
443                         if (graft && graft->nr_parent < 0)
444                                 continue;
445                         info->ours[info->nr_ours++] = i;
446                 } else
447                         info->theirs[info->nr_theirs++] = i;
448         }
449 }
450
451 void clear_shallow_info(struct shallow_info *info)
452 {
453         free(info->ours);
454         free(info->theirs);
455 }
456
457 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
458
459 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
460 {
461         struct object_id *oid = info->shallow->oid;
462         int i, dst;
463         trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
464         for (i = dst = 0; i < info->nr_theirs; i++) {
465                 if (i != dst)
466                         info->theirs[dst] = info->theirs[i];
467                 if (has_object_file(oid + info->theirs[i]))
468                         dst++;
469         }
470         info->nr_theirs = dst;
471 }
472
473 define_commit_slab(ref_bitmap, uint32_t *);
474
475 #define POOL_SIZE (512 * 1024)
476
477 struct paint_info {
478         struct ref_bitmap ref_bitmap;
479         unsigned nr_bits;
480         char **pools;
481         char *free, *end;
482         unsigned pool_count;
483 };
484
485 static uint32_t *paint_alloc(struct paint_info *info)
486 {
487         unsigned nr = DIV_ROUND_UP(info->nr_bits, 32);
488         unsigned size = nr * sizeof(uint32_t);
489         void *p;
490         if (!info->pool_count || size > info->end - info->free) {
491                 if (size > POOL_SIZE)
492                         BUG("pool size too small for %d in paint_alloc()",
493                             size);
494                 info->pool_count++;
495                 REALLOC_ARRAY(info->pools, info->pool_count);
496                 info->free = xmalloc(POOL_SIZE);
497                 info->pools[info->pool_count - 1] = info->free;
498                 info->end = info->free + POOL_SIZE;
499         }
500         p = info->free;
501         info->free += size;
502         return p;
503 }
504
505 /*
506  * Given a commit SHA-1, walk down to parents until either SEEN,
507  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
508  * all walked commits.
509  */
510 static void paint_down(struct paint_info *info, const struct object_id *oid,
511                        unsigned int id)
512 {
513         unsigned int i, nr;
514         struct commit_list *head = NULL;
515         int bitmap_nr = DIV_ROUND_UP(info->nr_bits, 32);
516         size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
517         struct commit *c = lookup_commit_reference_gently(the_repository, oid,
518                                                           1);
519         uint32_t *tmp; /* to be freed before return */
520         uint32_t *bitmap;
521
522         if (!c)
523                 return;
524
525         tmp = xmalloc(bitmap_size);
526         bitmap = paint_alloc(info);
527         memset(bitmap, 0, bitmap_size);
528         bitmap[id / 32] |= (1U << (id % 32));
529         commit_list_insert(c, &head);
530         while (head) {
531                 struct commit_list *p;
532                 struct commit *c = pop_commit(&head);
533                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
534
535                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
536                 if (c->object.flags & (SEEN | UNINTERESTING))
537                         continue;
538                 else
539                         c->object.flags |= SEEN;
540
541                 if (*refs == NULL)
542                         *refs = bitmap;
543                 else {
544                         memcpy(tmp, *refs, bitmap_size);
545                         for (i = 0; i < bitmap_nr; i++)
546                                 tmp[i] |= bitmap[i];
547                         if (memcmp(tmp, *refs, bitmap_size)) {
548                                 *refs = paint_alloc(info);
549                                 memcpy(*refs, tmp, bitmap_size);
550                         }
551                 }
552
553                 if (c->object.flags & BOTTOM)
554                         continue;
555
556                 if (parse_commit(c))
557                         die("unable to parse commit %s",
558                             oid_to_hex(&c->object.oid));
559
560                 for (p = c->parents; p; p = p->next) {
561                         if (p->item->object.flags & SEEN)
562                                 continue;
563                         commit_list_insert(p->item, &head);
564                 }
565         }
566
567         nr = get_max_object_index();
568         for (i = 0; i < nr; i++) {
569                 struct object *o = get_indexed_object(i);
570                 if (o && o->type == OBJ_COMMIT)
571                         o->flags &= ~SEEN;
572         }
573
574         free(tmp);
575 }
576
577 static int mark_uninteresting(const char *refname, const struct object_id *oid,
578                               int flags, void *cb_data)
579 {
580         struct commit *commit = lookup_commit_reference_gently(the_repository,
581                                                                oid, 1);
582         if (!commit)
583                 return 0;
584         commit->object.flags |= UNINTERESTING;
585         mark_parents_uninteresting(commit);
586         return 0;
587 }
588
589 static void post_assign_shallow(struct shallow_info *info,
590                                 struct ref_bitmap *ref_bitmap,
591                                 int *ref_status);
592 /*
593  * Step 6(+7), associate shallow commits with new refs
594  *
595  * info->ref must be initialized before calling this function.
596  *
597  * If used is not NULL, it's an array of info->shallow->nr
598  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
599  * m-th shallow commit from info->shallow.
600  *
601  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
602  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
603  * the ref needs some shallow commits from either info->ours or
604  * info->theirs.
605  */
606 void assign_shallow_commits_to_refs(struct shallow_info *info,
607                                     uint32_t **used, int *ref_status)
608 {
609         struct object_id *oid = info->shallow->oid;
610         struct oid_array *ref = info->ref;
611         unsigned int i, nr;
612         int *shallow, nr_shallow = 0;
613         struct paint_info pi;
614
615         trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
616         ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs);
617         for (i = 0; i < info->nr_ours; i++)
618                 shallow[nr_shallow++] = info->ours[i];
619         for (i = 0; i < info->nr_theirs; i++)
620                 shallow[nr_shallow++] = info->theirs[i];
621
622         /*
623          * Prepare the commit graph to track what refs can reach what
624          * (new) shallow commits.
625          */
626         nr = get_max_object_index();
627         for (i = 0; i < nr; i++) {
628                 struct object *o = get_indexed_object(i);
629                 if (!o || o->type != OBJ_COMMIT)
630                         continue;
631
632                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
633         }
634
635         memset(&pi, 0, sizeof(pi));
636         init_ref_bitmap(&pi.ref_bitmap);
637         pi.nr_bits = ref->nr;
638
639         /*
640          * "--not --all" to cut short the traversal if new refs
641          * connect to old refs. If not (e.g. force ref updates) it'll
642          * have to go down to the current shallow commits.
643          */
644         head_ref(mark_uninteresting, NULL);
645         for_each_ref(mark_uninteresting, NULL);
646
647         /* Mark potential bottoms so we won't go out of bound */
648         for (i = 0; i < nr_shallow; i++) {
649                 struct commit *c = lookup_commit(the_repository,
650                                                  &oid[shallow[i]]);
651                 c->object.flags |= BOTTOM;
652         }
653
654         for (i = 0; i < ref->nr; i++)
655                 paint_down(&pi, ref->oid + i, i);
656
657         if (used) {
658                 int bitmap_size = DIV_ROUND_UP(pi.nr_bits, 32) * sizeof(uint32_t);
659                 memset(used, 0, sizeof(*used) * info->shallow->nr);
660                 for (i = 0; i < nr_shallow; i++) {
661                         const struct commit *c = lookup_commit(the_repository,
662                                                                &oid[shallow[i]]);
663                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
664                         if (*map)
665                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
666                 }
667                 /*
668                  * unreachable shallow commits are not removed from
669                  * "ours" and "theirs". The user is supposed to run
670                  * step 7 on every ref separately and not trust "ours"
671                  * and "theirs" any more.
672                  */
673         } else
674                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
675
676         clear_ref_bitmap(&pi.ref_bitmap);
677         for (i = 0; i < pi.pool_count; i++)
678                 free(pi.pools[i]);
679         free(pi.pools);
680         free(shallow);
681 }
682
683 struct commit_array {
684         struct commit **commits;
685         int nr, alloc;
686 };
687
688 static int add_ref(const char *refname, const struct object_id *oid,
689                    int flags, void *cb_data)
690 {
691         struct commit_array *ca = cb_data;
692         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
693         ca->commits[ca->nr] = lookup_commit_reference_gently(the_repository,
694                                                              oid, 1);
695         if (ca->commits[ca->nr])
696                 ca->nr++;
697         return 0;
698 }
699
700 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
701 {
702         unsigned int i;
703         if (!ref_status)
704                 return;
705         for (i = 0; i < nr; i++)
706                 if (bitmap[i / 32] & (1U << (i % 32)))
707                         ref_status[i]++;
708 }
709
710 /*
711  * Step 7, reachability test on "ours" at commit level
712  */
713 static void post_assign_shallow(struct shallow_info *info,
714                                 struct ref_bitmap *ref_bitmap,
715                                 int *ref_status)
716 {
717         struct object_id *oid = info->shallow->oid;
718         struct commit *c;
719         uint32_t **bitmap;
720         int dst, i, j;
721         int bitmap_nr = DIV_ROUND_UP(info->ref->nr, 32);
722         struct commit_array ca;
723
724         trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
725         if (ref_status)
726                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
727
728         /* Remove unreachable shallow commits from "theirs" */
729         for (i = dst = 0; i < info->nr_theirs; i++) {
730                 if (i != dst)
731                         info->theirs[dst] = info->theirs[i];
732                 c = lookup_commit(the_repository, &oid[info->theirs[i]]);
733                 bitmap = ref_bitmap_at(ref_bitmap, c);
734                 if (!*bitmap)
735                         continue;
736                 for (j = 0; j < bitmap_nr; j++)
737                         if (bitmap[0][j]) {
738                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
739                                 dst++;
740                                 break;
741                         }
742         }
743         info->nr_theirs = dst;
744
745         memset(&ca, 0, sizeof(ca));
746         head_ref(add_ref, &ca);
747         for_each_ref(add_ref, &ca);
748
749         /* Remove unreachable shallow commits from "ours" */
750         for (i = dst = 0; i < info->nr_ours; i++) {
751                 if (i != dst)
752                         info->ours[dst] = info->ours[i];
753                 c = lookup_commit(the_repository, &oid[info->ours[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                             /* Step 7, reachability test at commit level */
760                             !in_merge_bases_many(c, ca.nr, ca.commits)) {
761                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
762                                 dst++;
763                                 break;
764                         }
765         }
766         info->nr_ours = dst;
767
768         free(ca.commits);
769 }
770
771 /* (Delayed) step 7, reachability test at commit level */
772 int delayed_reachability_test(struct shallow_info *si, int c)
773 {
774         if (si->need_reachability_test[c]) {
775                 struct commit *commit = lookup_commit(the_repository,
776                                                       &si->shallow->oid[c]);
777
778                 if (!si->commits) {
779                         struct commit_array ca;
780
781                         memset(&ca, 0, sizeof(ca));
782                         head_ref(add_ref, &ca);
783                         for_each_ref(add_ref, &ca);
784                         si->commits = ca.commits;
785                         si->nr_commits = ca.nr;
786                 }
787
788                 si->reachable[c] = in_merge_bases_many(commit,
789                                                        si->nr_commits,
790                                                        si->commits);
791                 si->need_reachability_test[c] = 0;
792         }
793         return si->reachable[c];
794 }