lockfile.h: extract new header file for the functions in lockfile.c
[git/git.git] / shallow.c
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "commit.h"
4 #include "tag.h"
5 #include "pkt-line.h"
6 #include "remote.h"
7 #include "refs.h"
8 #include "sha1-array.h"
9 #include "diff.h"
10 #include "revision.h"
11 #include "commit-slab.h"
12 #include "sigchain.h"
13
14 static int is_shallow = -1;
15 static struct stat_validity shallow_stat;
16 static char *alternate_shallow_file;
17
18 void set_alternate_shallow_file(const char *path, int override)
19 {
20 if (is_shallow != -1)
21 die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
22 if (alternate_shallow_file && !override)
23 return;
24 free(alternate_shallow_file);
25 alternate_shallow_file = path ? xstrdup(path) : NULL;
26 }
27
28 int register_shallow(const unsigned char *sha1)
29 {
30 struct commit_graft *graft =
31 xmalloc(sizeof(struct commit_graft));
32 struct commit *commit = lookup_commit(sha1);
33
34 hashcpy(graft->sha1, sha1);
35 graft->nr_parent = -1;
36 if (commit && commit->object.parsed)
37 commit->parents = NULL;
38 return register_commit_graft(graft, 0);
39 }
40
41 int is_repository_shallow(void)
42 {
43 FILE *fp;
44 char buf[1024];
45 const char *path = alternate_shallow_file;
46
47 if (is_shallow >= 0)
48 return is_shallow;
49
50 if (!path)
51 path = git_path("shallow");
52 /*
53 * fetch-pack sets '--shallow-file ""' as an indicator that no
54 * shallow file should be used. We could just open it and it
55 * will likely fail. But let's do an explicit check instead.
56 */
57 if (!*path || (fp = fopen(path, "r")) == NULL) {
58 stat_validity_clear(&shallow_stat);
59 is_shallow = 0;
60 return is_shallow;
61 }
62 stat_validity_update(&shallow_stat, fileno(fp));
63 is_shallow = 1;
64
65 while (fgets(buf, sizeof(buf), fp)) {
66 unsigned char sha1[20];
67 if (get_sha1_hex(buf, sha1))
68 die("bad shallow line: %s", buf);
69 register_shallow(sha1);
70 }
71 fclose(fp);
72 return is_shallow;
73 }
74
75 struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
76 int shallow_flag, int not_shallow_flag)
77 {
78 int i = 0, cur_depth = 0;
79 struct commit_list *result = NULL;
80 struct object_array stack = OBJECT_ARRAY_INIT;
81 struct commit *commit = NULL;
82 struct commit_graft *graft;
83
84 while (commit || i < heads->nr || stack.nr) {
85 struct commit_list *p;
86 if (!commit) {
87 if (i < heads->nr) {
88 commit = (struct commit *)
89 deref_tag(heads->objects[i++].item, NULL, 0);
90 if (!commit || commit->object.type != OBJ_COMMIT) {
91 commit = NULL;
92 continue;
93 }
94 if (!commit->util)
95 commit->util = xmalloc(sizeof(int));
96 *(int *)commit->util = 0;
97 cur_depth = 0;
98 } else {
99 commit = (struct commit *)
100 stack.objects[--stack.nr].item;
101 cur_depth = *(int *)commit->util;
102 }
103 }
104 parse_commit_or_die(commit);
105 cur_depth++;
106 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
107 (is_repository_shallow() && !commit->parents &&
108 (graft = lookup_commit_graft(commit->object.sha1)) != NULL &&
109 graft->nr_parent < 0)) {
110 commit_list_insert(commit, &result);
111 commit->object.flags |= shallow_flag;
112 commit = NULL;
113 continue;
114 }
115 commit->object.flags |= not_shallow_flag;
116 for (p = commit->parents, commit = NULL; p; p = p->next) {
117 if (!p->item->util) {
118 int *pointer = xmalloc(sizeof(int));
119 p->item->util = pointer;
120 *pointer = cur_depth;
121 } else {
122 int *pointer = p->item->util;
123 if (cur_depth >= *pointer)
124 continue;
125 *pointer = cur_depth;
126 }
127 if (p->next)
128 add_object_array(&p->item->object,
129 NULL, &stack);
130 else {
131 commit = p->item;
132 cur_depth = *(int *)commit->util;
133 }
134 }
135 }
136
137 return result;
138 }
139
140 void check_shallow_file_for_update(void)
141 {
142 if (is_shallow == -1)
143 die("BUG: shallow must be initialized by now");
144
145 if (!stat_validity_check(&shallow_stat, git_path("shallow")))
146 die("shallow file has changed since we read it");
147 }
148
149 #define SEEN_ONLY 1
150 #define VERBOSE 2
151
152 struct write_shallow_data {
153 struct strbuf *out;
154 int use_pack_protocol;
155 int count;
156 unsigned flags;
157 };
158
159 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
160 {
161 struct write_shallow_data *data = cb_data;
162 const char *hex = sha1_to_hex(graft->sha1);
163 if (graft->nr_parent != -1)
164 return 0;
165 if (data->flags & SEEN_ONLY) {
166 struct commit *c = lookup_commit(graft->sha1);
167 if (!c || !(c->object.flags & SEEN)) {
168 if (data->flags & VERBOSE)
169 printf("Removing %s from .git/shallow\n",
170 sha1_to_hex(c->object.sha1));
171 return 0;
172 }
173 }
174 data->count++;
175 if (data->use_pack_protocol)
176 packet_buf_write(data->out, "shallow %s", hex);
177 else {
178 strbuf_addstr(data->out, hex);
179 strbuf_addch(data->out, '\n');
180 }
181 return 0;
182 }
183
184 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
185 const struct sha1_array *extra,
186 unsigned flags)
187 {
188 struct write_shallow_data data;
189 int i;
190 data.out = out;
191 data.use_pack_protocol = use_pack_protocol;
192 data.count = 0;
193 data.flags = flags;
194 for_each_commit_graft(write_one_shallow, &data);
195 if (!extra)
196 return data.count;
197 for (i = 0; i < extra->nr; i++) {
198 strbuf_addstr(out, sha1_to_hex(extra->sha1[i]));
199 strbuf_addch(out, '\n');
200 data.count++;
201 }
202 return data.count;
203 }
204
205 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
206 const struct sha1_array *extra)
207 {
208 return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
209 }
210
211 static struct strbuf temporary_shallow = STRBUF_INIT;
212
213 static void remove_temporary_shallow(void)
214 {
215 if (temporary_shallow.len) {
216 unlink_or_warn(temporary_shallow.buf);
217 strbuf_reset(&temporary_shallow);
218 }
219 }
220
221 static void remove_temporary_shallow_on_signal(int signo)
222 {
223 remove_temporary_shallow();
224 sigchain_pop(signo);
225 raise(signo);
226 }
227
228 const char *setup_temporary_shallow(const struct sha1_array *extra)
229 {
230 static int installed_handler;
231 struct strbuf sb = STRBUF_INIT;
232 int fd;
233
234 if (temporary_shallow.len)
235 die("BUG: attempt to create two temporary shallow files");
236
237 if (write_shallow_commits(&sb, 0, extra)) {
238 strbuf_addstr(&temporary_shallow, git_path("shallow_XXXXXX"));
239 fd = xmkstemp(temporary_shallow.buf);
240
241 if (!installed_handler) {
242 atexit(remove_temporary_shallow);
243 sigchain_push_common(remove_temporary_shallow_on_signal);
244 }
245
246 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
247 die_errno("failed to write to %s",
248 temporary_shallow.buf);
249 close(fd);
250 strbuf_release(&sb);
251 return temporary_shallow.buf;
252 }
253 /*
254 * is_repository_shallow() sees empty string as "no shallow
255 * file".
256 */
257 return temporary_shallow.buf;
258 }
259
260 void setup_alternate_shallow(struct lock_file *shallow_lock,
261 const char **alternate_shallow_file,
262 const struct sha1_array *extra)
263 {
264 struct strbuf sb = STRBUF_INIT;
265 int fd;
266
267 fd = hold_lock_file_for_update(shallow_lock, git_path("shallow"),
268 LOCK_DIE_ON_ERROR);
269 check_shallow_file_for_update();
270 if (write_shallow_commits(&sb, 0, extra)) {
271 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
272 die_errno("failed to write to %s",
273 shallow_lock->filename.buf);
274 *alternate_shallow_file = shallow_lock->filename.buf;
275 } else
276 /*
277 * is_repository_shallow() sees empty string as "no
278 * shallow file".
279 */
280 *alternate_shallow_file = "";
281 strbuf_release(&sb);
282 }
283
284 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
285 {
286 int fd = *(int *)cb;
287 if (graft->nr_parent == -1)
288 packet_write(fd, "shallow %s\n", sha1_to_hex(graft->sha1));
289 return 0;
290 }
291
292 void advertise_shallow_grafts(int fd)
293 {
294 if (!is_repository_shallow())
295 return;
296 for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
297 }
298
299 /*
300 * mark_reachable_objects() should have been run prior to this and all
301 * reachable commits marked as "SEEN".
302 */
303 void prune_shallow(int show_only)
304 {
305 static struct lock_file shallow_lock;
306 struct strbuf sb = STRBUF_INIT;
307 int fd;
308
309 if (show_only) {
310 write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY | VERBOSE);
311 strbuf_release(&sb);
312 return;
313 }
314 fd = hold_lock_file_for_update(&shallow_lock, git_path("shallow"),
315 LOCK_DIE_ON_ERROR);
316 check_shallow_file_for_update();
317 if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
318 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
319 die_errno("failed to write to %s",
320 shallow_lock.filename.buf);
321 commit_lock_file(&shallow_lock);
322 } else {
323 unlink(git_path("shallow"));
324 rollback_lock_file(&shallow_lock);
325 }
326 strbuf_release(&sb);
327 }
328
329 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
330
331 /*
332 * Step 1, split sender shallow commits into "ours" and "theirs"
333 * Step 2, clean "ours" based on .git/shallow
334 */
335 void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
336 {
337 int i;
338 trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
339 memset(info, 0, sizeof(*info));
340 info->shallow = sa;
341 if (!sa)
342 return;
343 info->ours = xmalloc(sizeof(*info->ours) * sa->nr);
344 info->theirs = xmalloc(sizeof(*info->theirs) * sa->nr);
345 for (i = 0; i < sa->nr; i++) {
346 if (has_sha1_file(sa->sha1[i])) {
347 struct commit_graft *graft;
348 graft = lookup_commit_graft(sa->sha1[i]);
349 if (graft && graft->nr_parent < 0)
350 continue;
351 info->ours[info->nr_ours++] = i;
352 } else
353 info->theirs[info->nr_theirs++] = i;
354 }
355 }
356
357 void clear_shallow_info(struct shallow_info *info)
358 {
359 free(info->ours);
360 free(info->theirs);
361 }
362
363 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
364
365 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
366 {
367 unsigned char (*sha1)[20] = info->shallow->sha1;
368 int i, dst;
369 trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
370 for (i = dst = 0; i < info->nr_theirs; i++) {
371 if (i != dst)
372 info->theirs[dst] = info->theirs[i];
373 if (has_sha1_file(sha1[info->theirs[i]]))
374 dst++;
375 }
376 info->nr_theirs = dst;
377 }
378
379 define_commit_slab(ref_bitmap, uint32_t *);
380
381 struct paint_info {
382 struct ref_bitmap ref_bitmap;
383 unsigned nr_bits;
384 char **slab;
385 char *free, *end;
386 unsigned slab_count;
387 };
388
389 static uint32_t *paint_alloc(struct paint_info *info)
390 {
391 unsigned nr = (info->nr_bits + 31) / 32;
392 unsigned size = nr * sizeof(uint32_t);
393 void *p;
394 if (!info->slab_count || info->free + size > info->end) {
395 info->slab_count++;
396 REALLOC_ARRAY(info->slab, info->slab_count);
397 info->free = xmalloc(COMMIT_SLAB_SIZE);
398 info->slab[info->slab_count - 1] = info->free;
399 info->end = info->free + COMMIT_SLAB_SIZE;
400 }
401 p = info->free;
402 info->free += size;
403 return p;
404 }
405
406 /*
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.
410 */
411 static void paint_down(struct paint_info *info, const unsigned char *sha1,
412 int id)
413 {
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);
430
431 p = head;
432 head = head->next;
433 free(p);
434
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;
440
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);
450 }
451 }
452
453 if (c->object.flags & BOTTOM)
454 continue;
455
456 if (parse_commit(c))
457 die("unable to parse commit %s",
458 sha1_to_hex(c->object.sha1));
459
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);
468 }
469 }
470
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;
476 }
477
478 free(tmp);
479 }
480
481 static int mark_uninteresting(const char *refname,
482 const unsigned char *sha1,
483 int flags, void *cb_data)
484 {
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;
491 }
492
493 static void post_assign_shallow(struct shallow_info *info,
494 struct ref_bitmap *ref_bitmap,
495 int *ref_status);
496 /*
497 * Step 6(+7), associate shallow commits with new refs
498 *
499 * info->ref must be initialized before calling this function.
500 *
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.
504 *
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.
509 */
510 void assign_shallow_commits_to_refs(struct shallow_info *info,
511 uint32_t **used, int *ref_status)
512 {
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;
518
519 trace_printf_key(&trace_shallow, "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];
525
526 /*
527 * Prepare the commit graph to track what refs can reach what
528 * (new) shallow commits.
529 */
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;
535
536 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
537 }
538
539 memset(&pi, 0, sizeof(pi));
540 init_ref_bitmap(&pi.ref_bitmap);
541 pi.nr_bits = ref->nr;
542
543 /*
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.
547 */
548 head_ref(mark_uninteresting, NULL);
549 for_each_ref(mark_uninteresting, NULL);
550
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;
555 }
556
557 for (i = 0; i < ref->nr; i++)
558 paint_down(&pi, ref->sha1[i], i);
559
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);
568 }
569 /*
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.
574 */
575 } else
576 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
577
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);
583 }
584
585 struct commit_array {
586 struct commit **commits;
587 int nr, alloc;
588 };
589
590 static int add_ref(const char *refname,
591 const unsigned char *sha1, int flags, void *cb_data)
592 {
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;
599 }
600
601 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
602 {
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]++;
609 }
610
611 /*
612 * Step 7, reachability test on "ours" at commit level
613 */
614 static void post_assign_shallow(struct shallow_info *info,
615 struct ref_bitmap *ref_bitmap,
616 int *ref_status)
617 {
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;
624
625 trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
626 if (ref_status)
627 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
628
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;
642 }
643 }
644 info->nr_theirs = dst;
645
646 memset(&ca, 0, sizeof(ca));
647 head_ref(add_ref, &ca);
648 for_each_ref(add_ref, &ca);
649
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;
665 }
666 }
667 info->nr_ours = dst;
668
669 free(ca.commits);
670 }
671
672 /* (Delayed) step 7, reachability test at commit level */
673 int delayed_reachability_test(struct shallow_info *si, int c)
674 {
675 if (si->need_reachability_test[c]) {
676 struct commit *commit = lookup_commit(si->shallow->sha1[c]);
677
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;
685 }
686
687 si->reachable[c] = in_merge_bases_many(commit,
688 si->nr_commits,
689 si->commits);
690 si->need_reachability_test[c] = 0;
691 }
692 return si->reachable[c];
693 }