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"
11static int is_shallow = -1;
13static struct stat shallow_stat;
14static char *alternate_shallow_file;
15void set_alternate_shallow_file(const char *path, int override)
17{
18 if (is_shallow != -1)
19 die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
20 if (alternate_shallow_file && !override)
21 return;
22 free(alternate_shallow_file);
23 alternate_shallow_file = path ? xstrdup(path) : NULL;
24}
25int register_shallow(const unsigned char *sha1)
27{
28 struct commit_graft *graft =
29 xmalloc(sizeof(struct commit_graft));
30 struct commit *commit = lookup_commit(sha1);
31 hashcpy(graft->sha1, sha1);
33 graft->nr_parent = -1;
34 if (commit && commit->object.parsed)
35 commit->parents = NULL;
36 return register_commit_graft(graft, 0);
37}
38int is_repository_shallow(void)
40{
41 FILE *fp;
42 char buf[1024];
43 const char *path = alternate_shallow_file;
44 if (is_shallow >= 0)
46 return is_shallow;
47 if (!path)
49 path = git_path("shallow");
50 /*
51 * fetch-pack sets '--shallow-file ""' as an indicator that no
52 * shallow file should be used. We could just open it and it
53 * will likely fail. But let's do an explicit check instead.
54 */
55 if (!*path ||
56 stat(path, &shallow_stat) ||
57 (fp = fopen(path, "r")) == NULL) {
58 is_shallow = 0;
59 return is_shallow;
60 }
61 is_shallow = 1;
62 while (fgets(buf, sizeof(buf), fp)) {
64 unsigned char sha1[20];
65 if (get_sha1_hex(buf, sha1))
66 die("bad shallow line: %s", buf);
67 register_shallow(sha1);
68 }
69 fclose(fp);
70 return is_shallow;
71}
72struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
74 int shallow_flag, int not_shallow_flag)
75{
76 int i = 0, cur_depth = 0;
77 struct commit_list *result = NULL;
78 struct object_array stack = OBJECT_ARRAY_INIT;
79 struct commit *commit = NULL;
80 struct commit_graft *graft;
81 while (commit || i < heads->nr || stack.nr) {
83 struct commit_list *p;
84 if (!commit) {
85 if (i < heads->nr) {
86 commit = (struct commit *)
87 deref_tag(heads->objects[i++].item, NULL, 0);
88 if (!commit || commit->object.type != OBJ_COMMIT) {
89 commit = NULL;
90 continue;
91 }
92 if (!commit->util)
93 commit->util = xmalloc(sizeof(int));
94 *(int *)commit->util = 0;
95 cur_depth = 0;
96 } else {
97 commit = (struct commit *)
98 stack.objects[--stack.nr].item;
99 cur_depth = *(int *)commit->util;
100 }
101 }
102 if (parse_commit(commit))
103 die("invalid 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;
113 }
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;
125 }
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;
132 }
133 }
134 }
135 return result;
137}
138void check_shallow_file_for_update(void)
140{
141 struct stat st;
142 if (!is_shallow)
144 return;
145 else if (is_shallow == -1)
146 die("BUG: shallow must be initialized by now");
147 if (stat(git_path("shallow"), &st))
149 die("shallow file was removed during fetch");
150 else if (st.st_mtime != shallow_stat.st_mtime
151#ifdef USE_NSEC
152 || ST_MTIME_NSEC(st) != ST_MTIME_NSEC(shallow_stat)
153#endif
154 )
155 die("shallow file was changed during fetch");
156}
157struct write_shallow_data {
159 struct strbuf *out;
160 int use_pack_protocol;
161 int count;
162};
163static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
165{
166 struct write_shallow_data *data = cb_data;
167 const char *hex = sha1_to_hex(graft->sha1);
168 if (graft->nr_parent != -1)
169 return 0;
170 data->count++;
171 if (data->use_pack_protocol)
172 packet_buf_write(data->out, "shallow %s", hex);
173 else {
174 strbuf_addstr(data->out, hex);
175 strbuf_addch(data->out, '\n');
176 }
177 return 0;
178}
179int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
181 const struct sha1_array *extra)
182{
183 struct write_shallow_data data;
184 int i;
185 data.out = out;
186 data.use_pack_protocol = use_pack_protocol;
187 data.count = 0;
188 for_each_commit_graft(write_one_shallow, &data);
189 if (!extra)
190 return data.count;
191 for (i = 0; i < extra->nr; i++) {
192 strbuf_addstr(out, sha1_to_hex(extra->sha1[i]));
193 strbuf_addch(out, '\n');
194 data.count++;
195 }
196 return data.count;
197}
198char *setup_temporary_shallow(const struct sha1_array *extra)
200{
201 struct strbuf sb = STRBUF_INIT;
202 int fd;
203 if (write_shallow_commits(&sb, 0, extra)) {
205 struct strbuf path = STRBUF_INIT;
206 strbuf_addstr(&path, git_path("shallow_XXXXXX"));
207 fd = xmkstemp(path.buf);
208 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
209 die_errno("failed to write to %s",
210 path.buf);
211 close(fd);
212 strbuf_release(&sb);
213 return strbuf_detach(&path, NULL);
214 }
215 /*
216 * is_repository_shallow() sees empty string as "no shallow
217 * file".
218 */
219 return xstrdup("");
220}
221void setup_alternate_shallow(struct lock_file *shallow_lock,
223 const char **alternate_shallow_file,
224 const struct sha1_array *extra)
225{
226 struct strbuf sb = STRBUF_INIT;
227 int fd;
228 check_shallow_file_for_update();
230 fd = hold_lock_file_for_update(shallow_lock, git_path("shallow"),
231 LOCK_DIE_ON_ERROR);
232 if (write_shallow_commits(&sb, 0, extra)) {
233 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
234 die_errno("failed to write to %s",
235 shallow_lock->filename);
236 *alternate_shallow_file = shallow_lock->filename;
237 } else
238 /*
239 * is_repository_shallow() sees empty string as "no
240 * shallow file".
241 */
242 *alternate_shallow_file = "";
243 strbuf_release(&sb);
244}
245static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
247{
248 int fd = *(int *)cb;
249 if (graft->nr_parent == -1)
250 packet_write(fd, "shallow %s\n", sha1_to_hex(graft->sha1));
251 return 0;
252}
253void advertise_shallow_grafts(int fd)
255{
256 if (!is_repository_shallow())
257 return;
258 for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
259}
260#define TRACE_KEY "GIT_TRACE_SHALLOW"
262/*
264 * Step 1, split sender shallow commits into "ours" and "theirs"
265 * Step 2, clean "ours" based on .git/shallow
266 */
267void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
268{
269 int i;
270 trace_printf_key(TRACE_KEY, "shallow: prepare_shallow_info\n");
271 memset(info, 0, sizeof(*info));
272 info->shallow = sa;
273 if (!sa)
274 return;
275 info->ours = xmalloc(sizeof(*info->ours) * sa->nr);
276 info->theirs = xmalloc(sizeof(*info->theirs) * sa->nr);
277 for (i = 0; i < sa->nr; i++) {
278 if (has_sha1_file(sa->sha1[i])) {
279 struct commit_graft *graft;
280 graft = lookup_commit_graft(sa->sha1[i]);
281 if (graft && graft->nr_parent < 0)
282 continue;
283 info->ours[info->nr_ours++] = i;
284 } else
285 info->theirs[info->nr_theirs++] = i;
286 }
287}
288void clear_shallow_info(struct shallow_info *info)
290{
291 free(info->ours);
292 free(info->theirs);
293}
294/* Step 4, remove non-existent ones in "theirs" after getting the pack */
296void remove_nonexistent_theirs_shallow(struct shallow_info *info)
298{
299 unsigned char (*sha1)[20] = info->shallow->sha1;
300 int i, dst;
301 trace_printf_key(TRACE_KEY, "shallow: remove_nonexistent_theirs_shallow\n");
302 for (i = dst = 0; i < info->nr_theirs; i++) {
303 if (i != dst)
304 info->theirs[dst] = info->theirs[i];
305 if (has_sha1_file(sha1[info->theirs[i]]))
306 dst++;
307 }
308 info->nr_theirs = dst;
309}
310/* Step 5, remove non-existent ones in "ours" in the pack */
312void remove_nonexistent_ours_in_pack(struct shallow_info *info,
313 struct packed_git *p)
314{
315 unsigned char (*sha1)[20] = info->shallow->sha1;
316 int i, dst;
317 trace_printf_key(TRACE_KEY, "shallow: remove_nonexistent_ours_in_pack\n");
318 for (i = dst = 0; i < info->nr_ours; i++) {
319 if (i != dst)
320 info->ours[dst] = info->ours[i];
321 if (find_pack_entry_one(sha1[info->ours[i]], p))
322 dst++;
323 }
324 info->nr_ours = dst;
325}
326define_commit_slab(ref_bitmap, uint32_t *);
328struct paint_info {
330 struct ref_bitmap ref_bitmap;
331 unsigned nr_bits;
332 char **slab;
333 char *free, *end;
334 unsigned slab_count;
335};
336static uint32_t *paint_alloc(struct paint_info *info)
338{
339 unsigned nr = (info->nr_bits + 31) / 32;
340 unsigned size = nr * sizeof(uint32_t);
341 void *p;
342 if (!info->slab_count || info->free + size > info->end) {
343 info->slab_count++;
344 info->slab = xrealloc(info->slab,
345 info->slab_count * sizeof(*info->slab));
346 info->free = xmalloc(COMMIT_SLAB_SIZE);
347 info->slab[info->slab_count - 1] = info->free;
348 info->end = info->free + COMMIT_SLAB_SIZE;
349 }
350 p = info->free;
351 info->free += size;
352 return p;
353}
354/*
356 * Given a commit SHA-1, walk down to parents until either SEEN,
357 * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
358 * all walked commits.
359 */
360static void paint_down(struct paint_info *info, const unsigned char *sha1,
361 int id)
362{
363 unsigned int i, nr;
364 struct commit_list *head = NULL;
365 int bitmap_nr = (info->nr_bits + 31) / 32;
366 int bitmap_size = bitmap_nr * sizeof(uint32_t);
367 uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
368 uint32_t *bitmap = paint_alloc(info);
369 struct commit *c = lookup_commit_reference_gently(sha1, 1);
370 if (!c)
371 return;
372 memset(bitmap, 0, bitmap_size);
373 bitmap[id / 32] |= (1 << (id % 32));
374 commit_list_insert(c, &head);
375 while (head) {
376 struct commit_list *p;
377 struct commit *c = head->item;
378 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
379 p = head;
381 head = head->next;
382 free(p);
383 /* XXX check "UNINTERESTING" from pack bitmaps if available */
385 if (c->object.flags & (SEEN | UNINTERESTING))
386 continue;
387 else
388 c->object.flags |= SEEN;
389 if (*refs == NULL)
391 *refs = bitmap;
392 else {
393 memcpy(tmp, *refs, bitmap_size);
394 for (i = 0; i < bitmap_nr; i++)
395 tmp[i] |= bitmap[i];
396 if (memcmp(tmp, *refs, bitmap_size)) {
397 *refs = paint_alloc(info);
398 memcpy(*refs, tmp, bitmap_size);
399 }
400 }
401 if (c->object.flags & BOTTOM)
403 continue;
404 if (parse_commit(c))
406 die("unable to parse commit %s",
407 sha1_to_hex(c->object.sha1));
408 for (p = c->parents; p; p = p->next) {
410 uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
411 p->item);
412 if (p->item->object.flags & SEEN)
413 continue;
414 if (*p_refs == NULL || *p_refs == *refs)
415 *p_refs = *refs;
416 commit_list_insert(p->item, &head);
417 }
418 }
419 nr = get_max_object_index();
421 for (i = 0; i < nr; i++) {
422 struct object *o = get_indexed_object(i);
423 if (o && o->type == OBJ_COMMIT)
424 o->flags &= ~SEEN;
425 }
426 free(tmp);
428}
429static int mark_uninteresting(const char *refname,
431 const unsigned char *sha1,
432 int flags, void *cb_data)
433{
434 struct commit *commit = lookup_commit_reference_gently(sha1, 1);
435 if (!commit)
436 return 0;
437 commit->object.flags |= UNINTERESTING;
438 mark_parents_uninteresting(commit);
439 return 0;
440}
441static void post_assign_shallow(struct shallow_info *info,
443 struct ref_bitmap *ref_bitmap,
444 int *ref_status);
445/*
446 * Step 6(+7), associate shallow commits with new refs
447 *
448 * info->ref must be initialized before calling this function.
449 *
450 * If used is not NULL, it's an array of info->shallow->nr
451 * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
452 * m-th shallow commit from info->shallow.
453 *
454 * If used is NULL, "ours" and "theirs" are updated. And if ref_status
455 * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
456 * the ref needs some shallow commits from either info->ours or
457 * info->theirs.
458 */
459void assign_shallow_commits_to_refs(struct shallow_info *info,
460 uint32_t **used, int *ref_status)
461{
462 unsigned char (*sha1)[20] = info->shallow->sha1;
463 struct sha1_array *ref = info->ref;
464 unsigned int i, nr;
465 int *shallow, nr_shallow = 0;
466 struct paint_info pi;
467 trace_printf_key(TRACE_KEY, "shallow: assign_shallow_commits_to_refs\n");
469 shallow = xmalloc(sizeof(*shallow) * (info->nr_ours + info->nr_theirs));
470 for (i = 0; i < info->nr_ours; i++)
471 shallow[nr_shallow++] = info->ours[i];
472 for (i = 0; i < info->nr_theirs; i++)
473 shallow[nr_shallow++] = info->theirs[i];
474 /*
476 * Prepare the commit graph to track what refs can reach what
477 * (new) shallow commits.
478 */
479 nr = get_max_object_index();
480 for (i = 0; i < nr; i++) {
481 struct object *o = get_indexed_object(i);
482 if (!o || o->type != OBJ_COMMIT)
483 continue;
484 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
486 }
487 memset(&pi, 0, sizeof(pi));
489 init_ref_bitmap(&pi.ref_bitmap);
490 pi.nr_bits = ref->nr;
491 /*
493 * "--not --all" to cut short the traversal if new refs
494 * connect to old refs. If not (e.g. force ref updates) it'll
495 * have to go down to the current shallow commits.
496 */
497 head_ref(mark_uninteresting, NULL);
498 for_each_ref(mark_uninteresting, NULL);
499 /* Mark potential bottoms so we won't go out of bound */
501 for (i = 0; i < nr_shallow; i++) {
502 struct commit *c = lookup_commit(sha1[shallow[i]]);
503 c->object.flags |= BOTTOM;
504 }
505 for (i = 0; i < ref->nr; i++)
507 paint_down(&pi, ref->sha1[i], i);
508 if (used) {
510 int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
511 memset(used, 0, sizeof(*used) * info->shallow->nr);
512 for (i = 0; i < nr_shallow; i++) {
513 const struct commit *c = lookup_commit(sha1[shallow[i]]);
514 uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
515 if (*map)
516 used[shallow[i]] = xmemdupz(*map, bitmap_size);
517 }
518 /*
519 * unreachable shallow commits are not removed from
520 * "ours" and "theirs". The user is supposed to run
521 * step 7 on every ref separately and not trust "ours"
522 * and "theirs" any more.
523 */
524 } else
525 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
526 clear_ref_bitmap(&pi.ref_bitmap);
528 for (i = 0; i < pi.slab_count; i++)
529 free(pi.slab[i]);
530 free(pi.slab);
531 free(shallow);
532}
533struct commit_array {
535 struct commit **commits;
536 int nr, alloc;
537};
538static int add_ref(const char *refname,
540 const unsigned char *sha1, int flags, void *cb_data)
541{
542 struct commit_array *ca = cb_data;
543 ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
544 ca->commits[ca->nr] = lookup_commit_reference_gently(sha1, 1);
545 if (ca->commits[ca->nr])
546 ca->nr++;
547 return 0;
548}
549static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
551{
552 int i;
553 if (!ref_status)
554 return;
555 for (i = 0; i < nr; i++)
556 if (bitmap[i / 32] & (1 << (i % 32)))
557 ref_status[i]++;
558}
559/*
561 * Step 7, reachability test on "ours" at commit level
562 */
563static void post_assign_shallow(struct shallow_info *info,
564 struct ref_bitmap *ref_bitmap,
565 int *ref_status)
566{
567 unsigned char (*sha1)[20] = info->shallow->sha1;
568 struct commit *c;
569 uint32_t **bitmap;
570 int dst, i, j;
571 int bitmap_nr = (info->ref->nr + 31) / 32;
572 struct commit_array ca;
573 trace_printf_key(TRACE_KEY, "shallow: post_assign_shallow\n");
575 if (ref_status)
576 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
577 /* Remove unreachable shallow commits from "theirs" */
579 for (i = dst = 0; i < info->nr_theirs; i++) {
580 if (i != dst)
581 info->theirs[dst] = info->theirs[i];
582 c = lookup_commit(sha1[info->theirs[i]]);
583 bitmap = ref_bitmap_at(ref_bitmap, c);
584 if (!*bitmap)
585 continue;
586 for (j = 0; j < bitmap_nr; j++)
587 if (bitmap[0][j]) {
588 update_refstatus(ref_status, info->ref->nr, *bitmap);
589 dst++;
590 break;
591 }
592 }
593 info->nr_theirs = dst;
594 memset(&ca, 0, sizeof(ca));
596 head_ref(add_ref, &ca);
597 for_each_ref(add_ref, &ca);
598 /* Remove unreachable shallow commits from "ours" */
600 for (i = dst = 0; i < info->nr_ours; i++) {
601 if (i != dst)
602 info->ours[dst] = info->ours[i];
603 c = lookup_commit(sha1[info->ours[i]]);
604 bitmap = ref_bitmap_at(ref_bitmap, c);
605 if (!*bitmap)
606 continue;
607 for (j = 0; j < bitmap_nr; j++)
608 if (bitmap[0][j] &&
609 /* Step 7, reachability test at commit level */
610 !in_merge_bases_many(c, ca.nr, ca.commits)) {
611 update_refstatus(ref_status, info->ref->nr, *bitmap);
612 dst++;
613 break;
614 }
615 }
616 info->nr_ours = dst;
617 free(ca.commits);
619}
620/* (Delayed) step 7, reachability test at commit level */
622int delayed_reachability_test(struct shallow_info *si, int c)
623{
624 if (si->need_reachability_test[c]) {
625 struct commit *commit = lookup_commit(si->shallow->sha1[c]);
626 if (!si->commits) {
628 struct commit_array ca;
629 memset(&ca, 0, sizeof(ca));
630 head_ref(add_ref, &ca);
631 for_each_ref(add_ref, &ca);
632 si->commits = ca.commits;
633 si->nr_commits = ca.nr;
634 }
635 si->reachable[c] = in_merge_bases_many(commit,
637 si->nr_commits,
638 si->commits);
639 si->need_reachability_test[c] = 0;
640 }
641 return si->reachable[c];
642}