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