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[git.git] / shallow.c
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1 #include "cache.h"
2 #include "commit.h"
3 #include "tag.h"
4 #include "pkt-line.h"
5 #include "remote.h"
6 #include "refs.h"
7 #include "sha1-array.h"
8 #include "diff.h"
9 #include "revision.h"
10 #include "commit-slab.h"
11 #include "sigchain.h"
13 static int is_shallow = -1;
14 static struct stat_validity shallow_stat;
15 static char *alternate_shallow_file;
17 void set_alternate_shallow_file(const char *path, int override)
19 if (is_shallow != -1)
20 die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
21 if (alternate_shallow_file && !override)
22 return;
23 free(alternate_shallow_file);
24 alternate_shallow_file = path ? xstrdup(path) : NULL;
27 int register_shallow(const unsigned char *sha1)
29 struct commit_graft *graft =
30 xmalloc(sizeof(struct commit_graft));
31 struct commit *commit = lookup_commit(sha1);
33 hashcpy(graft->sha1, sha1);
34 graft->nr_parent = -1;
35 if (commit && commit->object.parsed)
36 commit->parents = NULL;
37 return register_commit_graft(graft, 0);
40 int is_repository_shallow(void)
42 FILE *fp;
43 char buf[1024];
44 const char *path = alternate_shallow_file;
46 if (is_shallow >= 0)
47 return is_shallow;
49 if (!path)
50 path = git_path("shallow");
52 * fetch-pack sets '--shallow-file ""' as an indicator that no
53 * shallow file should be used. We could just open it and it
54 * will likely fail. But let's do an explicit check instead.
56 if (!*path || (fp = fopen(path, "r")) == NULL) {
57 stat_validity_clear(&shallow_stat);
58 is_shallow = 0;
59 return is_shallow;
61 stat_validity_update(&shallow_stat, fileno(fp));
62 is_shallow = 1;
64 while (fgets(buf, sizeof(buf), fp)) {
65 unsigned char sha1[20];
66 if (get_sha1_hex(buf, sha1))
67 die("bad shallow line: %s", buf);
68 register_shallow(sha1);
70 fclose(fp);
71 return is_shallow;
74 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
75 int shallow_flag, int not_shallow_flag)
77 int i = 0, cur_depth = 0;
78 struct commit_list *result = NULL;
79 struct object_array stack = OBJECT_ARRAY_INIT;
80 struct commit *commit = NULL;
81 struct commit_graft *graft;
83 while (commit || i < heads->nr || stack.nr) {
84 struct commit_list *p;
85 if (!commit) {
86 if (i < heads->nr) {
87 commit = (struct commit *)
88 deref_tag(heads->objects[i++].item, NULL, 0);
89 if (!commit || commit->object.type != OBJ_COMMIT) {
90 commit = NULL;
91 continue;
93 if (!commit->util)
94 commit->util = xmalloc(sizeof(int));
95 *(int *)commit->util = 0;
96 cur_depth = 0;
97 } else {
98 commit = (struct commit *)
99 stack.objects[--stack.nr].item;
100 cur_depth = *(int *)commit->util;
103 parse_commit_or_die(commit);
104 cur_depth++;
105 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
106 (is_repository_shallow() && !commit->parents &&
107 (graft = lookup_commit_graft(commit->object.sha1)) != NULL &&
108 graft->nr_parent < 0)) {
109 commit_list_insert(commit, &result);
110 commit->object.flags |= shallow_flag;
111 commit = NULL;
112 continue;
114 commit->object.flags |= not_shallow_flag;
115 for (p = commit->parents, commit = NULL; p; p = p->next) {
116 if (!p->item->util) {
117 int *pointer = xmalloc(sizeof(int));
118 p->item->util = pointer;
119 *pointer = cur_depth;
120 } else {
121 int *pointer = p->item->util;
122 if (cur_depth >= *pointer)
123 continue;
124 *pointer = cur_depth;
126 if (p->next)
127 add_object_array(&p->item->object,
128 NULL, &stack);
129 else {
130 commit = p->item;
131 cur_depth = *(int *)commit->util;
136 return result;
139 void check_shallow_file_for_update(void)
141 if (is_shallow == -1)
142 die("BUG: shallow must be initialized by now");
144 if (!stat_validity_check(&shallow_stat, git_path("shallow")))
145 die("shallow file has changed since we read it");
148 #define SEEN_ONLY 1
149 #define VERBOSE 2
151 struct write_shallow_data {
152 struct strbuf *out;
153 int use_pack_protocol;
154 int count;
155 unsigned flags;
158 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
160 struct write_shallow_data *data = cb_data;
161 const char *hex = sha1_to_hex(graft->sha1);
162 if (graft->nr_parent != -1)
163 return 0;
164 if (data->flags & SEEN_ONLY) {
165 struct commit *c = lookup_commit(graft->sha1);
166 if (!c || !(c->object.flags & SEEN)) {
167 if (data->flags & VERBOSE)
168 printf("Removing %s from .git/shallow\n",
169 sha1_to_hex(c->object.sha1));
170 return 0;
173 data->count++;
174 if (data->use_pack_protocol)
175 packet_buf_write(data->out, "shallow %s", hex);
176 else {
177 strbuf_addstr(data->out, hex);
178 strbuf_addch(data->out, '\n');
180 return 0;
183 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
184 const struct sha1_array *extra,
185 unsigned flags)
187 struct write_shallow_data data;
188 int i;
189 data.out = out;
190 data.use_pack_protocol = use_pack_protocol;
191 data.count = 0;
192 data.flags = flags;
193 for_each_commit_graft(write_one_shallow, &data);
194 if (!extra)
195 return data.count;
196 for (i = 0; i < extra->nr; i++) {
197 strbuf_addstr(out, sha1_to_hex(extra->sha1[i]));
198 strbuf_addch(out, '\n');
199 data.count++;
201 return data.count;
204 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
205 const struct sha1_array *extra)
207 return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
210 static struct strbuf temporary_shallow = STRBUF_INIT;
212 static void remove_temporary_shallow(void)
214 if (temporary_shallow.len) {
215 unlink_or_warn(temporary_shallow.buf);
216 strbuf_reset(&temporary_shallow);
220 static void remove_temporary_shallow_on_signal(int signo)
222 remove_temporary_shallow();
223 sigchain_pop(signo);
224 raise(signo);
227 const char *setup_temporary_shallow(const struct sha1_array *extra)
229 static int installed_handler;
230 struct strbuf sb = STRBUF_INIT;
231 int fd;
233 if (temporary_shallow.len)
234 die("BUG: attempt to create two temporary shallow files");
236 if (write_shallow_commits(&sb, 0, extra)) {
237 strbuf_addstr(&temporary_shallow, git_path("shallow_XXXXXX"));
238 fd = xmkstemp(temporary_shallow.buf);
240 if (!installed_handler) {
241 atexit(remove_temporary_shallow);
242 sigchain_push_common(remove_temporary_shallow_on_signal);
245 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
246 die_errno("failed to write to %s",
247 temporary_shallow.buf);
248 close(fd);
249 strbuf_release(&sb);
250 return temporary_shallow.buf;
253 * is_repository_shallow() sees empty string as "no shallow
254 * file".
256 return temporary_shallow.buf;
259 void setup_alternate_shallow(struct lock_file *shallow_lock,
260 const char **alternate_shallow_file,
261 const struct sha1_array *extra)
263 struct strbuf sb = STRBUF_INIT;
264 int fd;
266 fd = hold_lock_file_for_update(shallow_lock, git_path("shallow"),
267 LOCK_DIE_ON_ERROR);
268 check_shallow_file_for_update();
269 if (write_shallow_commits(&sb, 0, extra)) {
270 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
271 die_errno("failed to write to %s",
272 shallow_lock->filename);
273 *alternate_shallow_file = shallow_lock->filename;
274 } else
276 * is_repository_shallow() sees empty string as "no
277 * shallow file".
279 *alternate_shallow_file = "";
280 strbuf_release(&sb);
283 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
285 int fd = *(int *)cb;
286 if (graft->nr_parent == -1)
287 packet_write(fd, "shallow %s\n", sha1_to_hex(graft->sha1));
288 return 0;
291 void advertise_shallow_grafts(int fd)
293 if (!is_repository_shallow())
294 return;
295 for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
299 * mark_reachable_objects() should have been run prior to this and all
300 * reachable commits marked as "SEEN".
302 void prune_shallow(int show_only)
304 static struct lock_file shallow_lock;
305 struct strbuf sb = STRBUF_INIT;
306 int fd;
308 if (show_only) {
309 write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY | VERBOSE);
310 strbuf_release(&sb);
311 return;
313 fd = hold_lock_file_for_update(&shallow_lock, git_path("shallow"),
314 LOCK_DIE_ON_ERROR);
315 check_shallow_file_for_update();
316 if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
317 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
318 die_errno("failed to write to %s",
319 shallow_lock.filename);
320 commit_lock_file(&shallow_lock);
321 } else {
322 unlink(git_path("shallow"));
323 rollback_lock_file(&shallow_lock);
325 strbuf_release(&sb);
328 #define TRACE_KEY "GIT_TRACE_SHALLOW"
331 * Step 1, split sender shallow commits into "ours" and "theirs"
332 * Step 2, clean "ours" based on .git/shallow
334 void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
336 int i;
337 trace_printf_key(TRACE_KEY, "shallow: prepare_shallow_info\n");
338 memset(info, 0, sizeof(*info));
339 info->shallow = sa;
340 if (!sa)
341 return;
342 info->ours = xmalloc(sizeof(*info->ours) * sa->nr);
343 info->theirs = xmalloc(sizeof(*info->theirs) * sa->nr);
344 for (i = 0; i < sa->nr; i++) {
345 if (has_sha1_file(sa->sha1[i])) {
346 struct commit_graft *graft;
347 graft = lookup_commit_graft(sa->sha1[i]);
348 if (graft && graft->nr_parent < 0)
349 continue;
350 info->ours[info->nr_ours++] = i;
351 } else
352 info->theirs[info->nr_theirs++] = i;
356 void clear_shallow_info(struct shallow_info *info)
358 free(info->ours);
359 free(info->theirs);
362 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
364 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
366 unsigned char (*sha1)[20] = info->shallow->sha1;
367 int i, dst;
368 trace_printf_key(TRACE_KEY, "shallow: remove_nonexistent_theirs_shallow\n");
369 for (i = dst = 0; i < info->nr_theirs; i++) {
370 if (i != dst)
371 info->theirs[dst] = info->theirs[i];
372 if (has_sha1_file(sha1[info->theirs[i]]))
373 dst++;
375 info->nr_theirs = dst;
378 define_commit_slab(ref_bitmap, uint32_t *);
380 struct paint_info {
381 struct ref_bitmap ref_bitmap;
382 unsigned nr_bits;
383 char **slab;
384 char *free, *end;
385 unsigned slab_count;
388 static uint32_t *paint_alloc(struct paint_info *info)
390 unsigned nr = (info->nr_bits + 31) / 32;
391 unsigned size = nr * sizeof(uint32_t);
392 void *p;
393 if (!info->slab_count || info->free + size > info->end) {
394 info->slab_count++;
395 info->slab = xrealloc(info->slab,
396 info->slab_count * sizeof(*info->slab));
397 info->free = xmalloc(COMMIT_SLAB_SIZE);
398 info->slab[info->slab_count - 1] = info->free;
399 info->end = info->free + COMMIT_SLAB_SIZE;
401 p = info->free;
402 info->free += size;
403 return p;
407 * Given a commit SHA-1, walk down to parents until either SEEN,
408 * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
409 * all walked commits.
411 static void paint_down(struct paint_info *info, const unsigned char *sha1,
412 int id)
414 unsigned int i, nr;
415 struct commit_list *head = NULL;
416 int bitmap_nr = (info->nr_bits + 31) / 32;
417 int bitmap_size = bitmap_nr * sizeof(uint32_t);
418 uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
419 uint32_t *bitmap = paint_alloc(info);
420 struct commit *c = lookup_commit_reference_gently(sha1, 1);
421 if (!c)
422 return;
423 memset(bitmap, 0, bitmap_size);
424 bitmap[id / 32] |= (1 << (id % 32));
425 commit_list_insert(c, &head);
426 while (head) {
427 struct commit_list *p;
428 struct commit *c = head->item;
429 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
431 p = head;
432 head = head->next;
433 free(p);
435 /* XXX check "UNINTERESTING" from pack bitmaps if available */
436 if (c->object.flags & (SEEN | UNINTERESTING))
437 continue;
438 else
439 c->object.flags |= SEEN;
441 if (*refs == NULL)
442 *refs = bitmap;
443 else {
444 memcpy(tmp, *refs, bitmap_size);
445 for (i = 0; i < bitmap_nr; i++)
446 tmp[i] |= bitmap[i];
447 if (memcmp(tmp, *refs, bitmap_size)) {
448 *refs = paint_alloc(info);
449 memcpy(*refs, tmp, bitmap_size);
453 if (c->object.flags & BOTTOM)
454 continue;
456 if (parse_commit(c))
457 die("unable to parse commit %s",
458 sha1_to_hex(c->object.sha1));
460 for (p = c->parents; p; p = p->next) {
461 uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
462 p->item);
463 if (p->item->object.flags & SEEN)
464 continue;
465 if (*p_refs == NULL || *p_refs == *refs)
466 *p_refs = *refs;
467 commit_list_insert(p->item, &head);
471 nr = get_max_object_index();
472 for (i = 0; i < nr; i++) {
473 struct object *o = get_indexed_object(i);
474 if (o && o->type == OBJ_COMMIT)
475 o->flags &= ~SEEN;
478 free(tmp);
481 static int mark_uninteresting(const char *refname,
482 const unsigned char *sha1,
483 int flags, void *cb_data)
485 struct commit *commit = lookup_commit_reference_gently(sha1, 1);
486 if (!commit)
487 return 0;
488 commit->object.flags |= UNINTERESTING;
489 mark_parents_uninteresting(commit);
490 return 0;
493 static void post_assign_shallow(struct shallow_info *info,
494 struct ref_bitmap *ref_bitmap,
495 int *ref_status);
497 * Step 6(+7), associate shallow commits with new refs
499 * info->ref must be initialized before calling this function.
501 * If used is not NULL, it's an array of info->shallow->nr
502 * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
503 * m-th shallow commit from info->shallow.
505 * If used is NULL, "ours" and "theirs" are updated. And if ref_status
506 * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
507 * the ref needs some shallow commits from either info->ours or
508 * info->theirs.
510 void assign_shallow_commits_to_refs(struct shallow_info *info,
511 uint32_t **used, int *ref_status)
513 unsigned char (*sha1)[20] = info->shallow->sha1;
514 struct sha1_array *ref = info->ref;
515 unsigned int i, nr;
516 int *shallow, nr_shallow = 0;
517 struct paint_info pi;
519 trace_printf_key(TRACE_KEY, "shallow: assign_shallow_commits_to_refs\n");
520 shallow = xmalloc(sizeof(*shallow) * (info->nr_ours + info->nr_theirs));
521 for (i = 0; i < info->nr_ours; i++)
522 shallow[nr_shallow++] = info->ours[i];
523 for (i = 0; i < info->nr_theirs; i++)
524 shallow[nr_shallow++] = info->theirs[i];
527 * Prepare the commit graph to track what refs can reach what
528 * (new) shallow commits.
530 nr = get_max_object_index();
531 for (i = 0; i < nr; i++) {
532 struct object *o = get_indexed_object(i);
533 if (!o || o->type != OBJ_COMMIT)
534 continue;
536 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
539 memset(&pi, 0, sizeof(pi));
540 init_ref_bitmap(&pi.ref_bitmap);
541 pi.nr_bits = ref->nr;
544 * "--not --all" to cut short the traversal if new refs
545 * connect to old refs. If not (e.g. force ref updates) it'll
546 * have to go down to the current shallow commits.
548 head_ref(mark_uninteresting, NULL);
549 for_each_ref(mark_uninteresting, NULL);
551 /* Mark potential bottoms so we won't go out of bound */
552 for (i = 0; i < nr_shallow; i++) {
553 struct commit *c = lookup_commit(sha1[shallow[i]]);
554 c->object.flags |= BOTTOM;
557 for (i = 0; i < ref->nr; i++)
558 paint_down(&pi, ref->sha1[i], i);
560 if (used) {
561 int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
562 memset(used, 0, sizeof(*used) * info->shallow->nr);
563 for (i = 0; i < nr_shallow; i++) {
564 const struct commit *c = lookup_commit(sha1[shallow[i]]);
565 uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
566 if (*map)
567 used[shallow[i]] = xmemdupz(*map, bitmap_size);
570 * unreachable shallow commits are not removed from
571 * "ours" and "theirs". The user is supposed to run
572 * step 7 on every ref separately and not trust "ours"
573 * and "theirs" any more.
575 } else
576 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
578 clear_ref_bitmap(&pi.ref_bitmap);
579 for (i = 0; i < pi.slab_count; i++)
580 free(pi.slab[i]);
581 free(pi.slab);
582 free(shallow);
585 struct commit_array {
586 struct commit **commits;
587 int nr, alloc;
590 static int add_ref(const char *refname,
591 const unsigned char *sha1, int flags, void *cb_data)
593 struct commit_array *ca = cb_data;
594 ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
595 ca->commits[ca->nr] = lookup_commit_reference_gently(sha1, 1);
596 if (ca->commits[ca->nr])
597 ca->nr++;
598 return 0;
601 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
603 int i;
604 if (!ref_status)
605 return;
606 for (i = 0; i < nr; i++)
607 if (bitmap[i / 32] & (1 << (i % 32)))
608 ref_status[i]++;
612 * Step 7, reachability test on "ours" at commit level
614 static void post_assign_shallow(struct shallow_info *info,
615 struct ref_bitmap *ref_bitmap,
616 int *ref_status)
618 unsigned char (*sha1)[20] = info->shallow->sha1;
619 struct commit *c;
620 uint32_t **bitmap;
621 int dst, i, j;
622 int bitmap_nr = (info->ref->nr + 31) / 32;
623 struct commit_array ca;
625 trace_printf_key(TRACE_KEY, "shallow: post_assign_shallow\n");
626 if (ref_status)
627 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
629 /* Remove unreachable shallow commits from "theirs" */
630 for (i = dst = 0; i < info->nr_theirs; i++) {
631 if (i != dst)
632 info->theirs[dst] = info->theirs[i];
633 c = lookup_commit(sha1[info->theirs[i]]);
634 bitmap = ref_bitmap_at(ref_bitmap, c);
635 if (!*bitmap)
636 continue;
637 for (j = 0; j < bitmap_nr; j++)
638 if (bitmap[0][j]) {
639 update_refstatus(ref_status, info->ref->nr, *bitmap);
640 dst++;
641 break;
644 info->nr_theirs = dst;
646 memset(&ca, 0, sizeof(ca));
647 head_ref(add_ref, &ca);
648 for_each_ref(add_ref, &ca);
650 /* Remove unreachable shallow commits from "ours" */
651 for (i = dst = 0; i < info->nr_ours; i++) {
652 if (i != dst)
653 info->ours[dst] = info->ours[i];
654 c = lookup_commit(sha1[info->ours[i]]);
655 bitmap = ref_bitmap_at(ref_bitmap, c);
656 if (!*bitmap)
657 continue;
658 for (j = 0; j < bitmap_nr; j++)
659 if (bitmap[0][j] &&
660 /* Step 7, reachability test at commit level */
661 !in_merge_bases_many(c, ca.nr, ca.commits)) {
662 update_refstatus(ref_status, info->ref->nr, *bitmap);
663 dst++;
664 break;
667 info->nr_ours = dst;
669 free(ca.commits);
672 /* (Delayed) step 7, reachability test at commit level */
673 int delayed_reachability_test(struct shallow_info *si, int c)
675 if (si->need_reachability_test[c]) {
676 struct commit *commit = lookup_commit(si->shallow->sha1[c]);
678 if (!si->commits) {
679 struct commit_array ca;
680 memset(&ca, 0, sizeof(ca));
681 head_ref(add_ref, &ca);
682 for_each_ref(add_ref, &ca);
683 si->commits = ca.commits;
684 si->nr_commits = ca.nr;
687 si->reachable[c] = in_merge_bases_many(commit,
688 si->nr_commits,
689 si->commits);
690 si->need_reachability_test[c] = 0;
692 return si->reachable[c];