Merge branch 'dl/t-readme-spell-git-correctly'
[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 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
114                 int shallow_flag, int not_shallow_flag)
115 {
116         int i = 0, cur_depth = 0;
117         struct commit_list *result = NULL;
118         struct object_array stack = OBJECT_ARRAY_INIT;
119         struct commit *commit = NULL;
120         struct commit_graft *graft;
121         struct commit_depth depths;
122
123         init_commit_depth(&depths);
124         while (commit || i < heads->nr || stack.nr) {
125                 struct commit_list *p;
126                 if (!commit) {
127                         if (i < heads->nr) {
128                                 int **depth_slot;
129                                 commit = (struct commit *)
130                                         deref_tag(the_repository,
131                                                   heads->objects[i++].item,
132                                                   NULL, 0);
133                                 if (!commit || commit->object.type != OBJ_COMMIT) {
134                                         commit = NULL;
135                                         continue;
136                                 }
137                                 depth_slot = commit_depth_at(&depths, commit);
138                                 if (!*depth_slot)
139                                         *depth_slot = xmalloc(sizeof(int));
140                                 **depth_slot = 0;
141                                 cur_depth = 0;
142                         } else {
143                                 commit = (struct commit *)
144                                         object_array_pop(&stack);
145                                 cur_depth = **commit_depth_at(&depths, commit);
146                         }
147                 }
148                 parse_commit_or_die(commit);
149                 cur_depth++;
150                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
151                     (is_repository_shallow(the_repository) && !commit->parents &&
152                      (graft = lookup_commit_graft(the_repository, &commit->object.oid)) != NULL &&
153                      graft->nr_parent < 0)) {
154                         commit_list_insert(commit, &result);
155                         commit->object.flags |= shallow_flag;
156                         commit = NULL;
157                         continue;
158                 }
159                 commit->object.flags |= not_shallow_flag;
160                 for (p = commit->parents, commit = NULL; p; p = p->next) {
161                         int **depth_slot = commit_depth_at(&depths, p->item);
162                         if (!*depth_slot) {
163                                 *depth_slot = xmalloc(sizeof(int));
164                                 **depth_slot = cur_depth;
165                         } else {
166                                 if (cur_depth >= **depth_slot)
167                                         continue;
168                                 **depth_slot = cur_depth;
169                         }
170                         if (p->next)
171                                 add_object_array(&p->item->object,
172                                                 NULL, &stack);
173                         else {
174                                 commit = p->item;
175                                 cur_depth = **commit_depth_at(&depths, commit);
176                         }
177                 }
178         }
179         for (i = 0; i < depths.slab_count; i++) {
180                 int j;
181
182                 if (!depths.slab[i])
183                         continue;
184                 for (j = 0; j < depths.slab_size; j++)
185                         free(depths.slab[i][j]);
186         }
187         clear_commit_depth(&depths);
188
189         return result;
190 }
191
192 static void show_commit(struct commit *commit, void *data)
193 {
194         commit_list_insert(commit, data);
195 }
196
197 /*
198  * Given rev-list arguments, run rev-list. All reachable commits
199  * except border ones are marked with not_shallow_flag. Border commits
200  * are marked with shallow_flag. The list of border/shallow commits
201  * are also returned.
202  */
203 struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av,
204                                                     int shallow_flag,
205                                                     int not_shallow_flag)
206 {
207         struct commit_list *result = NULL, *p;
208         struct commit_list *not_shallow_list = NULL;
209         struct rev_info revs;
210         int both_flags = shallow_flag | not_shallow_flag;
211
212         /*
213          * SHALLOW (excluded) and NOT_SHALLOW (included) should not be
214          * set at this point. But better be safe than sorry.
215          */
216         clear_object_flags(both_flags);
217
218         is_repository_shallow(the_repository); /* make sure shallows are read */
219
220         repo_init_revisions(the_repository, &revs, NULL);
221         save_commit_buffer = 0;
222         setup_revisions(ac, av, &revs, NULL);
223
224         if (prepare_revision_walk(&revs))
225                 die("revision walk setup failed");
226         traverse_commit_list(&revs, show_commit, NULL, &not_shallow_list);
227
228         if (!not_shallow_list)
229                 die("no commits selected for shallow requests");
230
231         /* Mark all reachable commits as NOT_SHALLOW */
232         for (p = not_shallow_list; p; p = p->next)
233                 p->item->object.flags |= not_shallow_flag;
234
235         /*
236          * mark border commits SHALLOW + NOT_SHALLOW.
237          * We cannot clear NOT_SHALLOW right now. Imagine border
238          * commit A is processed first, then commit B, whose parent is
239          * A, later. If NOT_SHALLOW on A is cleared at step 1, B
240          * itself is considered border at step 2, which is incorrect.
241          */
242         for (p = not_shallow_list; p; p = p->next) {
243                 struct commit *c = p->item;
244                 struct commit_list *parent;
245
246                 if (parse_commit(c))
247                         die("unable to parse commit %s",
248                             oid_to_hex(&c->object.oid));
249
250                 for (parent = c->parents; parent; parent = parent->next)
251                         if (!(parent->item->object.flags & not_shallow_flag)) {
252                                 c->object.flags |= shallow_flag;
253                                 commit_list_insert(c, &result);
254                                 break;
255                         }
256         }
257         free_commit_list(not_shallow_list);
258
259         /*
260          * Now we can clean up NOT_SHALLOW on border commits. Having
261          * both flags set can confuse the caller.
262          */
263         for (p = result; p; p = p->next) {
264                 struct object *o = &p->item->object;
265                 if ((o->flags & both_flags) == both_flags)
266                         o->flags &= ~not_shallow_flag;
267         }
268         return result;
269 }
270
271 static void check_shallow_file_for_update(struct repository *r)
272 {
273         if (r->parsed_objects->is_shallow == -1)
274                 BUG("shallow must be initialized by now");
275
276         if (!stat_validity_check(r->parsed_objects->shallow_stat,
277                                  git_path_shallow(r)))
278                 die("shallow file has changed since we read it");
279 }
280
281 #define SEEN_ONLY 1
282 #define VERBOSE   2
283 #define QUICK 4
284
285 struct write_shallow_data {
286         struct strbuf *out;
287         int use_pack_protocol;
288         int count;
289         unsigned flags;
290 };
291
292 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
293 {
294         struct write_shallow_data *data = cb_data;
295         const char *hex = oid_to_hex(&graft->oid);
296         if (graft->nr_parent != -1)
297                 return 0;
298         if (data->flags & QUICK) {
299                 if (!has_object_file(&graft->oid))
300                         return 0;
301         } else if (data->flags & SEEN_ONLY) {
302                 struct commit *c = lookup_commit(the_repository, &graft->oid);
303                 if (!c || !(c->object.flags & SEEN)) {
304                         if (data->flags & VERBOSE)
305                                 printf("Removing %s from .git/shallow\n",
306                                        oid_to_hex(&c->object.oid));
307                         return 0;
308                 }
309         }
310         data->count++;
311         if (data->use_pack_protocol)
312                 packet_buf_write(data->out, "shallow %s", hex);
313         else {
314                 strbuf_addstr(data->out, hex);
315                 strbuf_addch(data->out, '\n');
316         }
317         return 0;
318 }
319
320 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
321                                    const struct oid_array *extra,
322                                    unsigned flags)
323 {
324         struct write_shallow_data data;
325         int i;
326         data.out = out;
327         data.use_pack_protocol = use_pack_protocol;
328         data.count = 0;
329         data.flags = flags;
330         for_each_commit_graft(write_one_shallow, &data);
331         if (!extra)
332                 return data.count;
333         for (i = 0; i < extra->nr; i++) {
334                 strbuf_addstr(out, oid_to_hex(extra->oid + i));
335                 strbuf_addch(out, '\n');
336                 data.count++;
337         }
338         return data.count;
339 }
340
341 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
342                           const struct oid_array *extra)
343 {
344         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
345 }
346
347 const char *setup_temporary_shallow(const struct oid_array *extra)
348 {
349         struct tempfile *temp;
350         struct strbuf sb = STRBUF_INIT;
351
352         if (write_shallow_commits(&sb, 0, extra)) {
353                 temp = xmks_tempfile(git_path("shallow_XXXXXX"));
354
355                 if (write_in_full(temp->fd, sb.buf, sb.len) < 0 ||
356                     close_tempfile_gently(temp) < 0)
357                         die_errno("failed to write to %s",
358                                   get_tempfile_path(temp));
359                 strbuf_release(&sb);
360                 return get_tempfile_path(temp);
361         }
362         /*
363          * is_repository_shallow() sees empty string as "no shallow
364          * file".
365          */
366         return "";
367 }
368
369 void setup_alternate_shallow(struct shallow_lock *shallow_lock,
370                              const char **alternate_shallow_file,
371                              const struct oid_array *extra)
372 {
373         struct strbuf sb = STRBUF_INIT;
374         int fd;
375
376         fd = hold_lock_file_for_update(&shallow_lock->lock,
377                                        git_path_shallow(the_repository),
378                                        LOCK_DIE_ON_ERROR);
379         check_shallow_file_for_update(the_repository);
380         if (write_shallow_commits(&sb, 0, extra)) {
381                 if (write_in_full(fd, sb.buf, sb.len) < 0)
382                         die_errno("failed to write to %s",
383                                   get_lock_file_path(&shallow_lock->lock));
384                 *alternate_shallow_file = get_lock_file_path(&shallow_lock->lock);
385         } else
386                 /*
387                  * is_repository_shallow() sees empty string as "no
388                  * shallow file".
389                  */
390                 *alternate_shallow_file = "";
391         strbuf_release(&sb);
392 }
393
394 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
395 {
396         int fd = *(int *)cb;
397         if (graft->nr_parent == -1)
398                 packet_write_fmt(fd, "shallow %s\n", oid_to_hex(&graft->oid));
399         return 0;
400 }
401
402 void advertise_shallow_grafts(int fd)
403 {
404         if (!is_repository_shallow(the_repository))
405                 return;
406         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
407 }
408
409 /*
410  * mark_reachable_objects() should have been run prior to this and all
411  * reachable commits marked as "SEEN", except when quick_prune is non-zero,
412  * in which case lines are excised from the shallow file if they refer to
413  * commits that do not exist (any longer).
414  */
415 void prune_shallow(unsigned options)
416 {
417         struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
418         struct strbuf sb = STRBUF_INIT;
419         unsigned flags = SEEN_ONLY;
420         int fd;
421
422         if (options & PRUNE_QUICK)
423                 flags |= QUICK;
424
425         if (options & PRUNE_SHOW_ONLY) {
426                 flags |= VERBOSE;
427                 write_shallow_commits_1(&sb, 0, NULL, flags);
428                 strbuf_release(&sb);
429                 return;
430         }
431         fd = hold_lock_file_for_update(&shallow_lock.lock,
432                                        git_path_shallow(the_repository),
433                                        LOCK_DIE_ON_ERROR);
434         check_shallow_file_for_update(the_repository);
435         if (write_shallow_commits_1(&sb, 0, NULL, flags)) {
436                 if (write_in_full(fd, sb.buf, sb.len) < 0)
437                         die_errno("failed to write to %s",
438                                   get_lock_file_path(&shallow_lock.lock));
439                 commit_shallow_file(the_repository, &shallow_lock);
440         } else {
441                 unlink(git_path_shallow(the_repository));
442                 rollback_shallow_file(the_repository, &shallow_lock);
443         }
444         strbuf_release(&sb);
445 }
446
447 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
448
449 /*
450  * Step 1, split sender shallow commits into "ours" and "theirs"
451  * Step 2, clean "ours" based on .git/shallow
452  */
453 void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa)
454 {
455         int i;
456         trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
457         memset(info, 0, sizeof(*info));
458         info->shallow = sa;
459         if (!sa)
460                 return;
461         ALLOC_ARRAY(info->ours, sa->nr);
462         ALLOC_ARRAY(info->theirs, sa->nr);
463         for (i = 0; i < sa->nr; i++) {
464                 if (has_object_file(sa->oid + i)) {
465                         struct commit_graft *graft;
466                         graft = lookup_commit_graft(the_repository,
467                                                     &sa->oid[i]);
468                         if (graft && graft->nr_parent < 0)
469                                 continue;
470                         info->ours[info->nr_ours++] = i;
471                 } else
472                         info->theirs[info->nr_theirs++] = i;
473         }
474 }
475
476 void clear_shallow_info(struct shallow_info *info)
477 {
478         free(info->ours);
479         free(info->theirs);
480 }
481
482 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
483
484 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
485 {
486         struct object_id *oid = info->shallow->oid;
487         int i, dst;
488         trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
489         for (i = dst = 0; i < info->nr_theirs; i++) {
490                 if (i != dst)
491                         info->theirs[dst] = info->theirs[i];
492                 if (has_object_file(oid + info->theirs[i]))
493                         dst++;
494         }
495         info->nr_theirs = dst;
496 }
497
498 define_commit_slab(ref_bitmap, uint32_t *);
499
500 #define POOL_SIZE (512 * 1024)
501
502 struct paint_info {
503         struct ref_bitmap ref_bitmap;
504         unsigned nr_bits;
505         char **pools;
506         char *free, *end;
507         unsigned pool_count;
508 };
509
510 static uint32_t *paint_alloc(struct paint_info *info)
511 {
512         unsigned nr = DIV_ROUND_UP(info->nr_bits, 32);
513         unsigned size = nr * sizeof(uint32_t);
514         void *p;
515         if (!info->pool_count || size > info->end - info->free) {
516                 if (size > POOL_SIZE)
517                         BUG("pool size too small for %d in paint_alloc()",
518                             size);
519                 info->pool_count++;
520                 REALLOC_ARRAY(info->pools, info->pool_count);
521                 info->free = xmalloc(POOL_SIZE);
522                 info->pools[info->pool_count - 1] = info->free;
523                 info->end = info->free + POOL_SIZE;
524         }
525         p = info->free;
526         info->free += size;
527         return p;
528 }
529
530 /*
531  * Given a commit SHA-1, walk down to parents until either SEEN,
532  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
533  * all walked commits.
534  */
535 static void paint_down(struct paint_info *info, const struct object_id *oid,
536                        unsigned int id)
537 {
538         unsigned int i, nr;
539         struct commit_list *head = NULL;
540         int bitmap_nr = DIV_ROUND_UP(info->nr_bits, 32);
541         size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
542         struct commit *c = lookup_commit_reference_gently(the_repository, oid,
543                                                           1);
544         uint32_t *tmp; /* to be freed before return */
545         uint32_t *bitmap;
546
547         if (!c)
548                 return;
549
550         tmp = xmalloc(bitmap_size);
551         bitmap = paint_alloc(info);
552         memset(bitmap, 0, bitmap_size);
553         bitmap[id / 32] |= (1U << (id % 32));
554         commit_list_insert(c, &head);
555         while (head) {
556                 struct commit_list *p;
557                 struct commit *c = pop_commit(&head);
558                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
559
560                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
561                 if (c->object.flags & (SEEN | UNINTERESTING))
562                         continue;
563                 else
564                         c->object.flags |= SEEN;
565
566                 if (*refs == NULL)
567                         *refs = bitmap;
568                 else {
569                         memcpy(tmp, *refs, bitmap_size);
570                         for (i = 0; i < bitmap_nr; i++)
571                                 tmp[i] |= bitmap[i];
572                         if (memcmp(tmp, *refs, bitmap_size)) {
573                                 *refs = paint_alloc(info);
574                                 memcpy(*refs, tmp, bitmap_size);
575                         }
576                 }
577
578                 if (c->object.flags & BOTTOM)
579                         continue;
580
581                 if (parse_commit(c))
582                         die("unable to parse commit %s",
583                             oid_to_hex(&c->object.oid));
584
585                 for (p = c->parents; p; p = p->next) {
586                         if (p->item->object.flags & SEEN)
587                                 continue;
588                         commit_list_insert(p->item, &head);
589                 }
590         }
591
592         nr = get_max_object_index();
593         for (i = 0; i < nr; i++) {
594                 struct object *o = get_indexed_object(i);
595                 if (o && o->type == OBJ_COMMIT)
596                         o->flags &= ~SEEN;
597         }
598
599         free(tmp);
600 }
601
602 static int mark_uninteresting(const char *refname, const struct object_id *oid,
603                               int flags, void *cb_data)
604 {
605         struct commit *commit = lookup_commit_reference_gently(the_repository,
606                                                                oid, 1);
607         if (!commit)
608                 return 0;
609         commit->object.flags |= UNINTERESTING;
610         mark_parents_uninteresting(commit);
611         return 0;
612 }
613
614 static void post_assign_shallow(struct shallow_info *info,
615                                 struct ref_bitmap *ref_bitmap,
616                                 int *ref_status);
617 /*
618  * Step 6(+7), associate shallow commits with new refs
619  *
620  * info->ref must be initialized before calling this function.
621  *
622  * If used is not NULL, it's an array of info->shallow->nr
623  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
624  * m-th shallow commit from info->shallow.
625  *
626  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
627  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
628  * the ref needs some shallow commits from either info->ours or
629  * info->theirs.
630  */
631 void assign_shallow_commits_to_refs(struct shallow_info *info,
632                                     uint32_t **used, int *ref_status)
633 {
634         struct object_id *oid = info->shallow->oid;
635         struct oid_array *ref = info->ref;
636         unsigned int i, nr;
637         int *shallow, nr_shallow = 0;
638         struct paint_info pi;
639
640         trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
641         ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs);
642         for (i = 0; i < info->nr_ours; i++)
643                 shallow[nr_shallow++] = info->ours[i];
644         for (i = 0; i < info->nr_theirs; i++)
645                 shallow[nr_shallow++] = info->theirs[i];
646
647         /*
648          * Prepare the commit graph to track what refs can reach what
649          * (new) shallow commits.
650          */
651         nr = get_max_object_index();
652         for (i = 0; i < nr; i++) {
653                 struct object *o = get_indexed_object(i);
654                 if (!o || o->type != OBJ_COMMIT)
655                         continue;
656
657                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
658         }
659
660         memset(&pi, 0, sizeof(pi));
661         init_ref_bitmap(&pi.ref_bitmap);
662         pi.nr_bits = ref->nr;
663
664         /*
665          * "--not --all" to cut short the traversal if new refs
666          * connect to old refs. If not (e.g. force ref updates) it'll
667          * have to go down to the current shallow commits.
668          */
669         head_ref(mark_uninteresting, NULL);
670         for_each_ref(mark_uninteresting, NULL);
671
672         /* Mark potential bottoms so we won't go out of bound */
673         for (i = 0; i < nr_shallow; i++) {
674                 struct commit *c = lookup_commit(the_repository,
675                                                  &oid[shallow[i]]);
676                 c->object.flags |= BOTTOM;
677         }
678
679         for (i = 0; i < ref->nr; i++)
680                 paint_down(&pi, ref->oid + i, i);
681
682         if (used) {
683                 int bitmap_size = DIV_ROUND_UP(pi.nr_bits, 32) * sizeof(uint32_t);
684                 memset(used, 0, sizeof(*used) * info->shallow->nr);
685                 for (i = 0; i < nr_shallow; i++) {
686                         const struct commit *c = lookup_commit(the_repository,
687                                                                &oid[shallow[i]]);
688                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
689                         if (*map)
690                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
691                 }
692                 /*
693                  * unreachable shallow commits are not removed from
694                  * "ours" and "theirs". The user is supposed to run
695                  * step 7 on every ref separately and not trust "ours"
696                  * and "theirs" any more.
697                  */
698         } else
699                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
700
701         clear_ref_bitmap(&pi.ref_bitmap);
702         for (i = 0; i < pi.pool_count; i++)
703                 free(pi.pools[i]);
704         free(pi.pools);
705         free(shallow);
706 }
707
708 struct commit_array {
709         struct commit **commits;
710         int nr, alloc;
711 };
712
713 static int add_ref(const char *refname, const struct object_id *oid,
714                    int flags, void *cb_data)
715 {
716         struct commit_array *ca = cb_data;
717         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
718         ca->commits[ca->nr] = lookup_commit_reference_gently(the_repository,
719                                                              oid, 1);
720         if (ca->commits[ca->nr])
721                 ca->nr++;
722         return 0;
723 }
724
725 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
726 {
727         unsigned int i;
728         if (!ref_status)
729                 return;
730         for (i = 0; i < nr; i++)
731                 if (bitmap[i / 32] & (1U << (i % 32)))
732                         ref_status[i]++;
733 }
734
735 /*
736  * Step 7, reachability test on "ours" at commit level
737  */
738 static void post_assign_shallow(struct shallow_info *info,
739                                 struct ref_bitmap *ref_bitmap,
740                                 int *ref_status)
741 {
742         struct object_id *oid = info->shallow->oid;
743         struct commit *c;
744         uint32_t **bitmap;
745         int dst, i, j;
746         int bitmap_nr = DIV_ROUND_UP(info->ref->nr, 32);
747         struct commit_array ca;
748
749         trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
750         if (ref_status)
751                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
752
753         /* Remove unreachable shallow commits from "theirs" */
754         for (i = dst = 0; i < info->nr_theirs; i++) {
755                 if (i != dst)
756                         info->theirs[dst] = info->theirs[i];
757                 c = lookup_commit(the_repository, &oid[info->theirs[i]]);
758                 bitmap = ref_bitmap_at(ref_bitmap, c);
759                 if (!*bitmap)
760                         continue;
761                 for (j = 0; j < bitmap_nr; j++)
762                         if (bitmap[0][j]) {
763                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
764                                 dst++;
765                                 break;
766                         }
767         }
768         info->nr_theirs = dst;
769
770         memset(&ca, 0, sizeof(ca));
771         head_ref(add_ref, &ca);
772         for_each_ref(add_ref, &ca);
773
774         /* Remove unreachable shallow commits from "ours" */
775         for (i = dst = 0; i < info->nr_ours; i++) {
776                 if (i != dst)
777                         info->ours[dst] = info->ours[i];
778                 c = lookup_commit(the_repository, &oid[info->ours[i]]);
779                 bitmap = ref_bitmap_at(ref_bitmap, c);
780                 if (!*bitmap)
781                         continue;
782                 for (j = 0; j < bitmap_nr; j++)
783                         if (bitmap[0][j] &&
784                             /* Step 7, reachability test at commit level */
785                             !in_merge_bases_many(c, ca.nr, ca.commits)) {
786                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
787                                 dst++;
788                                 break;
789                         }
790         }
791         info->nr_ours = dst;
792
793         free(ca.commits);
794 }
795
796 /* (Delayed) step 7, reachability test at commit level */
797 int delayed_reachability_test(struct shallow_info *si, int c)
798 {
799         if (si->need_reachability_test[c]) {
800                 struct commit *commit = lookup_commit(the_repository,
801                                                       &si->shallow->oid[c]);
802
803                 if (!si->commits) {
804                         struct commit_array ca;
805
806                         memset(&ca, 0, sizeof(ca));
807                         head_ref(add_ref, &ca);
808                         for_each_ref(add_ref, &ca);
809                         si->commits = ca.commits;
810                         si->nr_commits = ca.nr;
811                 }
812
813                 si->reachable[c] = in_merge_bases_many(commit,
814                                                        si->nr_commits,
815                                                        si->commits);
816                 si->need_reachability_test[c] = 0;
817         }
818         return si->reachable[c];
819 }