Merge branch 'tk/sigchain-unnecessary-post-tempfile'
[git/git.git] / shallow.c
1 #include "cache.h"
2 #include "tempfile.h"
3 #include "lockfile.h"
4 #include "commit.h"
5 #include "tag.h"
6 #include "pkt-line.h"
7 #include "remote.h"
8 #include "refs.h"
9 #include "sha1-array.h"
10 #include "diff.h"
11 #include "revision.h"
12 #include "commit-slab.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 = xstrdup_or_null(path);
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->oid.hash, 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 static 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 = oid_to_hex(&graft->oid);
163 if (graft->nr_parent != -1)
164 return 0;
165 if (data->flags & SEEN_ONLY) {
166 struct commit *c = lookup_commit(graft->oid.hash);
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 tempfile temporary_shallow;
212
213 const char *setup_temporary_shallow(const struct sha1_array *extra)
214 {
215 struct strbuf sb = STRBUF_INIT;
216 int fd;
217
218 if (write_shallow_commits(&sb, 0, extra)) {
219 fd = xmks_tempfile(&temporary_shallow, git_path("shallow_XXXXXX"));
220
221 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
222 die_errno("failed to write to %s",
223 get_tempfile_path(&temporary_shallow));
224 close_tempfile(&temporary_shallow);
225 strbuf_release(&sb);
226 return get_tempfile_path(&temporary_shallow);
227 }
228 /*
229 * is_repository_shallow() sees empty string as "no shallow
230 * file".
231 */
232 return get_tempfile_path(&temporary_shallow);
233 }
234
235 void setup_alternate_shallow(struct lock_file *shallow_lock,
236 const char **alternate_shallow_file,
237 const struct sha1_array *extra)
238 {
239 struct strbuf sb = STRBUF_INIT;
240 int fd;
241
242 fd = hold_lock_file_for_update(shallow_lock, git_path_shallow(),
243 LOCK_DIE_ON_ERROR);
244 check_shallow_file_for_update();
245 if (write_shallow_commits(&sb, 0, extra)) {
246 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
247 die_errno("failed to write to %s",
248 get_lock_file_path(shallow_lock));
249 *alternate_shallow_file = get_lock_file_path(shallow_lock);
250 } else
251 /*
252 * is_repository_shallow() sees empty string as "no
253 * shallow file".
254 */
255 *alternate_shallow_file = "";
256 strbuf_release(&sb);
257 }
258
259 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
260 {
261 int fd = *(int *)cb;
262 if (graft->nr_parent == -1)
263 packet_write(fd, "shallow %s\n", oid_to_hex(&graft->oid));
264 return 0;
265 }
266
267 void advertise_shallow_grafts(int fd)
268 {
269 if (!is_repository_shallow())
270 return;
271 for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
272 }
273
274 /*
275 * mark_reachable_objects() should have been run prior to this and all
276 * reachable commits marked as "SEEN".
277 */
278 void prune_shallow(int show_only)
279 {
280 static struct lock_file shallow_lock;
281 struct strbuf sb = STRBUF_INIT;
282 int fd;
283
284 if (show_only) {
285 write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY | VERBOSE);
286 strbuf_release(&sb);
287 return;
288 }
289 fd = hold_lock_file_for_update(&shallow_lock, git_path_shallow(),
290 LOCK_DIE_ON_ERROR);
291 check_shallow_file_for_update();
292 if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
293 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
294 die_errno("failed to write to %s",
295 get_lock_file_path(&shallow_lock));
296 commit_lock_file(&shallow_lock);
297 } else {
298 unlink(git_path_shallow());
299 rollback_lock_file(&shallow_lock);
300 }
301 strbuf_release(&sb);
302 }
303
304 struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW);
305
306 /*
307 * Step 1, split sender shallow commits into "ours" and "theirs"
308 * Step 2, clean "ours" based on .git/shallow
309 */
310 void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
311 {
312 int i;
313 trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
314 memset(info, 0, sizeof(*info));
315 info->shallow = sa;
316 if (!sa)
317 return;
318 info->ours = xmalloc(sizeof(*info->ours) * sa->nr);
319 info->theirs = xmalloc(sizeof(*info->theirs) * sa->nr);
320 for (i = 0; i < sa->nr; i++) {
321 if (has_sha1_file(sa->sha1[i])) {
322 struct commit_graft *graft;
323 graft = lookup_commit_graft(sa->sha1[i]);
324 if (graft && graft->nr_parent < 0)
325 continue;
326 info->ours[info->nr_ours++] = i;
327 } else
328 info->theirs[info->nr_theirs++] = i;
329 }
330 }
331
332 void clear_shallow_info(struct shallow_info *info)
333 {
334 free(info->ours);
335 free(info->theirs);
336 }
337
338 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
339
340 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
341 {
342 unsigned char (*sha1)[20] = info->shallow->sha1;
343 int i, dst;
344 trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
345 for (i = dst = 0; i < info->nr_theirs; i++) {
346 if (i != dst)
347 info->theirs[dst] = info->theirs[i];
348 if (has_sha1_file(sha1[info->theirs[i]]))
349 dst++;
350 }
351 info->nr_theirs = dst;
352 }
353
354 define_commit_slab(ref_bitmap, uint32_t *);
355
356 struct paint_info {
357 struct ref_bitmap ref_bitmap;
358 unsigned nr_bits;
359 char **slab;
360 char *free, *end;
361 unsigned slab_count;
362 };
363
364 static uint32_t *paint_alloc(struct paint_info *info)
365 {
366 unsigned nr = (info->nr_bits + 31) / 32;
367 unsigned size = nr * sizeof(uint32_t);
368 void *p;
369 if (!info->slab_count || info->free + size > info->end) {
370 info->slab_count++;
371 REALLOC_ARRAY(info->slab, info->slab_count);
372 info->free = xmalloc(COMMIT_SLAB_SIZE);
373 info->slab[info->slab_count - 1] = info->free;
374 info->end = info->free + COMMIT_SLAB_SIZE;
375 }
376 p = info->free;
377 info->free += size;
378 return p;
379 }
380
381 /*
382 * Given a commit SHA-1, walk down to parents until either SEEN,
383 * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
384 * all walked commits.
385 */
386 static void paint_down(struct paint_info *info, const unsigned char *sha1,
387 int id)
388 {
389 unsigned int i, nr;
390 struct commit_list *head = NULL;
391 int bitmap_nr = (info->nr_bits + 31) / 32;
392 int bitmap_size = bitmap_nr * sizeof(uint32_t);
393 uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
394 uint32_t *bitmap = paint_alloc(info);
395 struct commit *c = lookup_commit_reference_gently(sha1, 1);
396 if (!c)
397 return;
398 memset(bitmap, 0, bitmap_size);
399 bitmap[id / 32] |= (1 << (id % 32));
400 commit_list_insert(c, &head);
401 while (head) {
402 struct commit_list *p;
403 struct commit *c = head->item;
404 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
405
406 p = head;
407 head = head->next;
408 free(p);
409
410 /* XXX check "UNINTERESTING" from pack bitmaps if available */
411 if (c->object.flags & (SEEN | UNINTERESTING))
412 continue;
413 else
414 c->object.flags |= SEEN;
415
416 if (*refs == NULL)
417 *refs = bitmap;
418 else {
419 memcpy(tmp, *refs, bitmap_size);
420 for (i = 0; i < bitmap_nr; i++)
421 tmp[i] |= bitmap[i];
422 if (memcmp(tmp, *refs, bitmap_size)) {
423 *refs = paint_alloc(info);
424 memcpy(*refs, tmp, bitmap_size);
425 }
426 }
427
428 if (c->object.flags & BOTTOM)
429 continue;
430
431 if (parse_commit(c))
432 die("unable to parse commit %s",
433 sha1_to_hex(c->object.sha1));
434
435 for (p = c->parents; p; p = p->next) {
436 uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
437 p->item);
438 if (p->item->object.flags & SEEN)
439 continue;
440 if (*p_refs == NULL || *p_refs == *refs)
441 *p_refs = *refs;
442 commit_list_insert(p->item, &head);
443 }
444 }
445
446 nr = get_max_object_index();
447 for (i = 0; i < nr; i++) {
448 struct object *o = get_indexed_object(i);
449 if (o && o->type == OBJ_COMMIT)
450 o->flags &= ~SEEN;
451 }
452
453 free(tmp);
454 }
455
456 static int mark_uninteresting(const char *refname, const struct object_id *oid,
457 int flags, void *cb_data)
458 {
459 struct commit *commit = lookup_commit_reference_gently(oid->hash, 1);
460 if (!commit)
461 return 0;
462 commit->object.flags |= UNINTERESTING;
463 mark_parents_uninteresting(commit);
464 return 0;
465 }
466
467 static void post_assign_shallow(struct shallow_info *info,
468 struct ref_bitmap *ref_bitmap,
469 int *ref_status);
470 /*
471 * Step 6(+7), associate shallow commits with new refs
472 *
473 * info->ref must be initialized before calling this function.
474 *
475 * If used is not NULL, it's an array of info->shallow->nr
476 * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
477 * m-th shallow commit from info->shallow.
478 *
479 * If used is NULL, "ours" and "theirs" are updated. And if ref_status
480 * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
481 * the ref needs some shallow commits from either info->ours or
482 * info->theirs.
483 */
484 void assign_shallow_commits_to_refs(struct shallow_info *info,
485 uint32_t **used, int *ref_status)
486 {
487 unsigned char (*sha1)[20] = info->shallow->sha1;
488 struct sha1_array *ref = info->ref;
489 unsigned int i, nr;
490 int *shallow, nr_shallow = 0;
491 struct paint_info pi;
492
493 trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n");
494 shallow = xmalloc(sizeof(*shallow) * (info->nr_ours + info->nr_theirs));
495 for (i = 0; i < info->nr_ours; i++)
496 shallow[nr_shallow++] = info->ours[i];
497 for (i = 0; i < info->nr_theirs; i++)
498 shallow[nr_shallow++] = info->theirs[i];
499
500 /*
501 * Prepare the commit graph to track what refs can reach what
502 * (new) shallow commits.
503 */
504 nr = get_max_object_index();
505 for (i = 0; i < nr; i++) {
506 struct object *o = get_indexed_object(i);
507 if (!o || o->type != OBJ_COMMIT)
508 continue;
509
510 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
511 }
512
513 memset(&pi, 0, sizeof(pi));
514 init_ref_bitmap(&pi.ref_bitmap);
515 pi.nr_bits = ref->nr;
516
517 /*
518 * "--not --all" to cut short the traversal if new refs
519 * connect to old refs. If not (e.g. force ref updates) it'll
520 * have to go down to the current shallow commits.
521 */
522 head_ref(mark_uninteresting, NULL);
523 for_each_ref(mark_uninteresting, NULL);
524
525 /* Mark potential bottoms so we won't go out of bound */
526 for (i = 0; i < nr_shallow; i++) {
527 struct commit *c = lookup_commit(sha1[shallow[i]]);
528 c->object.flags |= BOTTOM;
529 }
530
531 for (i = 0; i < ref->nr; i++)
532 paint_down(&pi, ref->sha1[i], i);
533
534 if (used) {
535 int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
536 memset(used, 0, sizeof(*used) * info->shallow->nr);
537 for (i = 0; i < nr_shallow; i++) {
538 const struct commit *c = lookup_commit(sha1[shallow[i]]);
539 uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
540 if (*map)
541 used[shallow[i]] = xmemdupz(*map, bitmap_size);
542 }
543 /*
544 * unreachable shallow commits are not removed from
545 * "ours" and "theirs". The user is supposed to run
546 * step 7 on every ref separately and not trust "ours"
547 * and "theirs" any more.
548 */
549 } else
550 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
551
552 clear_ref_bitmap(&pi.ref_bitmap);
553 for (i = 0; i < pi.slab_count; i++)
554 free(pi.slab[i]);
555 free(pi.slab);
556 free(shallow);
557 }
558
559 struct commit_array {
560 struct commit **commits;
561 int nr, alloc;
562 };
563
564 static int add_ref(const char *refname, const struct object_id *oid,
565 int flags, void *cb_data)
566 {
567 struct commit_array *ca = cb_data;
568 ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
569 ca->commits[ca->nr] = lookup_commit_reference_gently(oid->hash, 1);
570 if (ca->commits[ca->nr])
571 ca->nr++;
572 return 0;
573 }
574
575 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
576 {
577 int i;
578 if (!ref_status)
579 return;
580 for (i = 0; i < nr; i++)
581 if (bitmap[i / 32] & (1 << (i % 32)))
582 ref_status[i]++;
583 }
584
585 /*
586 * Step 7, reachability test on "ours" at commit level
587 */
588 static void post_assign_shallow(struct shallow_info *info,
589 struct ref_bitmap *ref_bitmap,
590 int *ref_status)
591 {
592 unsigned char (*sha1)[20] = info->shallow->sha1;
593 struct commit *c;
594 uint32_t **bitmap;
595 int dst, i, j;
596 int bitmap_nr = (info->ref->nr + 31) / 32;
597 struct commit_array ca;
598
599 trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n");
600 if (ref_status)
601 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
602
603 /* Remove unreachable shallow commits from "theirs" */
604 for (i = dst = 0; i < info->nr_theirs; i++) {
605 if (i != dst)
606 info->theirs[dst] = info->theirs[i];
607 c = lookup_commit(sha1[info->theirs[i]]);
608 bitmap = ref_bitmap_at(ref_bitmap, c);
609 if (!*bitmap)
610 continue;
611 for (j = 0; j < bitmap_nr; j++)
612 if (bitmap[0][j]) {
613 update_refstatus(ref_status, info->ref->nr, *bitmap);
614 dst++;
615 break;
616 }
617 }
618 info->nr_theirs = dst;
619
620 memset(&ca, 0, sizeof(ca));
621 head_ref(add_ref, &ca);
622 for_each_ref(add_ref, &ca);
623
624 /* Remove unreachable shallow commits from "ours" */
625 for (i = dst = 0; i < info->nr_ours; i++) {
626 if (i != dst)
627 info->ours[dst] = info->ours[i];
628 c = lookup_commit(sha1[info->ours[i]]);
629 bitmap = ref_bitmap_at(ref_bitmap, c);
630 if (!*bitmap)
631 continue;
632 for (j = 0; j < bitmap_nr; j++)
633 if (bitmap[0][j] &&
634 /* Step 7, reachability test at commit level */
635 !in_merge_bases_many(c, ca.nr, ca.commits)) {
636 update_refstatus(ref_status, info->ref->nr, *bitmap);
637 dst++;
638 break;
639 }
640 }
641 info->nr_ours = dst;
642
643 free(ca.commits);
644 }
645
646 /* (Delayed) step 7, reachability test at commit level */
647 int delayed_reachability_test(struct shallow_info *si, int c)
648 {
649 if (si->need_reachability_test[c]) {
650 struct commit *commit = lookup_commit(si->shallow->sha1[c]);
651
652 if (!si->commits) {
653 struct commit_array ca;
654
655 memset(&ca, 0, sizeof(ca));
656 head_ref(add_ref, &ca);
657 for_each_ref(add_ref, &ca);
658 si->commits = ca.commits;
659 si->nr_commits = ca.nr;
660 }
661
662 si->reachable[c] = in_merge_bases_many(commit,
663 si->nr_commits,
664 si->commits);
665 si->need_reachability_test[c] = 0;
666 }
667 return si->reachable[c];
668 }