Merge branch 'ta/parse-commit-with-skip-prefix'
[git] / shallow.c
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
12 static int is_shallow = -1;
13 static struct stat shallow_stat;
14 static char *alternate_shallow_file;
15
16 void 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 }
25
26 int 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
32         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 }
38
39 int is_repository_shallow(void)
40 {
41         FILE *fp;
42         char buf[1024];
43         const char *path = alternate_shallow_file;
44
45         if (is_shallow >= 0)
46                 return is_shallow;
47
48         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
63         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 }
72
73 struct 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
82         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                 parse_commit_or_die(commit);
103                 cur_depth++;
104                 if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
105                     (is_repository_shallow() && !commit->parents &&
106                      (graft = lookup_commit_graft(commit->object.sha1)) != NULL &&
107                      graft->nr_parent < 0)) {
108                         commit_list_insert(commit, &result);
109                         commit->object.flags |= shallow_flag;
110                         commit = NULL;
111                         continue;
112                 }
113                 commit->object.flags |= not_shallow_flag;
114                 for (p = commit->parents, commit = NULL; p; p = p->next) {
115                         if (!p->item->util) {
116                                 int *pointer = xmalloc(sizeof(int));
117                                 p->item->util = pointer;
118                                 *pointer =  cur_depth;
119                         } else {
120                                 int *pointer = p->item->util;
121                                 if (cur_depth >= *pointer)
122                                         continue;
123                                 *pointer = cur_depth;
124                         }
125                         if (p->next)
126                                 add_object_array(&p->item->object,
127                                                 NULL, &stack);
128                         else {
129                                 commit = p->item;
130                                 cur_depth = *(int *)commit->util;
131                         }
132                 }
133         }
134
135         return result;
136 }
137
138 void check_shallow_file_for_update(void)
139 {
140         struct stat st;
141
142         if (!is_shallow)
143                 return;
144         else if (is_shallow == -1)
145                 die("BUG: shallow must be initialized by now");
146
147         if (stat(git_path("shallow"), &st))
148                 die("shallow file was removed during fetch");
149         else if (st.st_mtime != shallow_stat.st_mtime
150 #ifdef USE_NSEC
151                  || ST_MTIME_NSEC(st) != ST_MTIME_NSEC(shallow_stat)
152 #endif
153                    )
154                 die("shallow file was changed during fetch");
155 }
156
157 #define SEEN_ONLY 1
158 #define VERBOSE   2
159
160 struct write_shallow_data {
161         struct strbuf *out;
162         int use_pack_protocol;
163         int count;
164         unsigned flags;
165 };
166
167 static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
168 {
169         struct write_shallow_data *data = cb_data;
170         const char *hex = sha1_to_hex(graft->sha1);
171         if (graft->nr_parent != -1)
172                 return 0;
173         if (data->flags & SEEN_ONLY) {
174                 struct commit *c = lookup_commit(graft->sha1);
175                 if (!c || !(c->object.flags & SEEN)) {
176                         if (data->flags & VERBOSE)
177                                 printf("Removing %s from .git/shallow\n",
178                                        sha1_to_hex(c->object.sha1));
179                         return 0;
180                 }
181         }
182         data->count++;
183         if (data->use_pack_protocol)
184                 packet_buf_write(data->out, "shallow %s", hex);
185         else {
186                 strbuf_addstr(data->out, hex);
187                 strbuf_addch(data->out, '\n');
188         }
189         return 0;
190 }
191
192 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
193                                    const struct sha1_array *extra,
194                                    unsigned flags)
195 {
196         struct write_shallow_data data;
197         int i;
198         data.out = out;
199         data.use_pack_protocol = use_pack_protocol;
200         data.count = 0;
201         data.flags = flags;
202         for_each_commit_graft(write_one_shallow, &data);
203         if (!extra)
204                 return data.count;
205         for (i = 0; i < extra->nr; i++) {
206                 strbuf_addstr(out, sha1_to_hex(extra->sha1[i]));
207                 strbuf_addch(out, '\n');
208                 data.count++;
209         }
210         return data.count;
211 }
212
213 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
214                           const struct sha1_array *extra)
215 {
216         return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
217 }
218
219 char *setup_temporary_shallow(const struct sha1_array *extra)
220 {
221         struct strbuf sb = STRBUF_INIT;
222         int fd;
223
224         if (write_shallow_commits(&sb, 0, extra)) {
225                 struct strbuf path = STRBUF_INIT;
226                 strbuf_addstr(&path, git_path("shallow_XXXXXX"));
227                 fd = xmkstemp(path.buf);
228                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
229                         die_errno("failed to write to %s",
230                                   path.buf);
231                 close(fd);
232                 strbuf_release(&sb);
233                 return strbuf_detach(&path, NULL);
234         }
235         /*
236          * is_repository_shallow() sees empty string as "no shallow
237          * file".
238          */
239         return xstrdup("");
240 }
241
242 void setup_alternate_shallow(struct lock_file *shallow_lock,
243                              const char **alternate_shallow_file,
244                              const struct sha1_array *extra)
245 {
246         struct strbuf sb = STRBUF_INIT;
247         int fd;
248
249         check_shallow_file_for_update();
250         fd = hold_lock_file_for_update(shallow_lock, git_path("shallow"),
251                                        LOCK_DIE_ON_ERROR);
252         if (write_shallow_commits(&sb, 0, extra)) {
253                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
254                         die_errno("failed to write to %s",
255                                   shallow_lock->filename);
256                 *alternate_shallow_file = shallow_lock->filename;
257         } else
258                 /*
259                  * is_repository_shallow() sees empty string as "no
260                  * shallow file".
261                  */
262                 *alternate_shallow_file = "";
263         strbuf_release(&sb);
264 }
265
266 static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
267 {
268         int fd = *(int *)cb;
269         if (graft->nr_parent == -1)
270                 packet_write(fd, "shallow %s\n", sha1_to_hex(graft->sha1));
271         return 0;
272 }
273
274 void advertise_shallow_grafts(int fd)
275 {
276         if (!is_repository_shallow())
277                 return;
278         for_each_commit_graft(advertise_shallow_grafts_cb, &fd);
279 }
280
281 /*
282  * mark_reachable_objects() should have been run prior to this and all
283  * reachable commits marked as "SEEN".
284  */
285 void prune_shallow(int show_only)
286 {
287         static struct lock_file shallow_lock;
288         struct strbuf sb = STRBUF_INIT;
289         int fd;
290
291         if (show_only) {
292                 write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY | VERBOSE);
293                 strbuf_release(&sb);
294                 return;
295         }
296         check_shallow_file_for_update();
297         fd = hold_lock_file_for_update(&shallow_lock, git_path("shallow"),
298                                        LOCK_DIE_ON_ERROR);
299         if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
300                 if (write_in_full(fd, sb.buf, sb.len) != sb.len)
301                         die_errno("failed to write to %s",
302                                   shallow_lock.filename);
303                 commit_lock_file(&shallow_lock);
304         } else {
305                 unlink(git_path("shallow"));
306                 rollback_lock_file(&shallow_lock);
307         }
308         strbuf_release(&sb);
309 }
310
311 #define TRACE_KEY "GIT_TRACE_SHALLOW"
312
313 /*
314  * Step 1, split sender shallow commits into "ours" and "theirs"
315  * Step 2, clean "ours" based on .git/shallow
316  */
317 void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
318 {
319         int i;
320         trace_printf_key(TRACE_KEY, "shallow: prepare_shallow_info\n");
321         memset(info, 0, sizeof(*info));
322         info->shallow = sa;
323         if (!sa)
324                 return;
325         info->ours = xmalloc(sizeof(*info->ours) * sa->nr);
326         info->theirs = xmalloc(sizeof(*info->theirs) * sa->nr);
327         for (i = 0; i < sa->nr; i++) {
328                 if (has_sha1_file(sa->sha1[i])) {
329                         struct commit_graft *graft;
330                         graft = lookup_commit_graft(sa->sha1[i]);
331                         if (graft && graft->nr_parent < 0)
332                                 continue;
333                         info->ours[info->nr_ours++] = i;
334                 } else
335                         info->theirs[info->nr_theirs++] = i;
336         }
337 }
338
339 void clear_shallow_info(struct shallow_info *info)
340 {
341         free(info->ours);
342         free(info->theirs);
343 }
344
345 /* Step 4, remove non-existent ones in "theirs" after getting the pack */
346
347 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
348 {
349         unsigned char (*sha1)[20] = info->shallow->sha1;
350         int i, dst;
351         trace_printf_key(TRACE_KEY, "shallow: remove_nonexistent_theirs_shallow\n");
352         for (i = dst = 0; i < info->nr_theirs; i++) {
353                 if (i != dst)
354                         info->theirs[dst] = info->theirs[i];
355                 if (has_sha1_file(sha1[info->theirs[i]]))
356                         dst++;
357         }
358         info->nr_theirs = dst;
359 }
360
361 define_commit_slab(ref_bitmap, uint32_t *);
362
363 struct paint_info {
364         struct ref_bitmap ref_bitmap;
365         unsigned nr_bits;
366         char **slab;
367         char *free, *end;
368         unsigned slab_count;
369 };
370
371 static uint32_t *paint_alloc(struct paint_info *info)
372 {
373         unsigned nr = (info->nr_bits + 31) / 32;
374         unsigned size = nr * sizeof(uint32_t);
375         void *p;
376         if (!info->slab_count || info->free + size > info->end) {
377                 info->slab_count++;
378                 info->slab = xrealloc(info->slab,
379                                       info->slab_count * sizeof(*info->slab));
380                 info->free = xmalloc(COMMIT_SLAB_SIZE);
381                 info->slab[info->slab_count - 1] = info->free;
382                 info->end = info->free + COMMIT_SLAB_SIZE;
383         }
384         p = info->free;
385         info->free += size;
386         return p;
387 }
388
389 /*
390  * Given a commit SHA-1, walk down to parents until either SEEN,
391  * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
392  * all walked commits.
393  */
394 static void paint_down(struct paint_info *info, const unsigned char *sha1,
395                        int id)
396 {
397         unsigned int i, nr;
398         struct commit_list *head = NULL;
399         int bitmap_nr = (info->nr_bits + 31) / 32;
400         int bitmap_size = bitmap_nr * sizeof(uint32_t);
401         uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
402         uint32_t *bitmap = paint_alloc(info);
403         struct commit *c = lookup_commit_reference_gently(sha1, 1);
404         if (!c)
405                 return;
406         memset(bitmap, 0, bitmap_size);
407         bitmap[id / 32] |= (1 << (id % 32));
408         commit_list_insert(c, &head);
409         while (head) {
410                 struct commit_list *p;
411                 struct commit *c = head->item;
412                 uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
413
414                 p = head;
415                 head = head->next;
416                 free(p);
417
418                 /* XXX check "UNINTERESTING" from pack bitmaps if available */
419                 if (c->object.flags & (SEEN | UNINTERESTING))
420                         continue;
421                 else
422                         c->object.flags |= SEEN;
423
424                 if (*refs == NULL)
425                         *refs = bitmap;
426                 else {
427                         memcpy(tmp, *refs, bitmap_size);
428                         for (i = 0; i < bitmap_nr; i++)
429                                 tmp[i] |= bitmap[i];
430                         if (memcmp(tmp, *refs, bitmap_size)) {
431                                 *refs = paint_alloc(info);
432                                 memcpy(*refs, tmp, bitmap_size);
433                         }
434                 }
435
436                 if (c->object.flags & BOTTOM)
437                         continue;
438
439                 if (parse_commit(c))
440                         die("unable to parse commit %s",
441                             sha1_to_hex(c->object.sha1));
442
443                 for (p = c->parents; p; p = p->next) {
444                         uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
445                                                           p->item);
446                         if (p->item->object.flags & SEEN)
447                                 continue;
448                         if (*p_refs == NULL || *p_refs == *refs)
449                                 *p_refs = *refs;
450                         commit_list_insert(p->item, &head);
451                 }
452         }
453
454         nr = get_max_object_index();
455         for (i = 0; i < nr; i++) {
456                 struct object *o = get_indexed_object(i);
457                 if (o && o->type == OBJ_COMMIT)
458                         o->flags &= ~SEEN;
459         }
460
461         free(tmp);
462 }
463
464 static int mark_uninteresting(const char *refname,
465                               const unsigned char *sha1,
466                               int flags, void *cb_data)
467 {
468         struct commit *commit = lookup_commit_reference_gently(sha1, 1);
469         if (!commit)
470                 return 0;
471         commit->object.flags |= UNINTERESTING;
472         mark_parents_uninteresting(commit);
473         return 0;
474 }
475
476 static void post_assign_shallow(struct shallow_info *info,
477                                 struct ref_bitmap *ref_bitmap,
478                                 int *ref_status);
479 /*
480  * Step 6(+7), associate shallow commits with new refs
481  *
482  * info->ref must be initialized before calling this function.
483  *
484  * If used is not NULL, it's an array of info->shallow->nr
485  * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
486  * m-th shallow commit from info->shallow.
487  *
488  * If used is NULL, "ours" and "theirs" are updated. And if ref_status
489  * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
490  * the ref needs some shallow commits from either info->ours or
491  * info->theirs.
492  */
493 void assign_shallow_commits_to_refs(struct shallow_info *info,
494                                     uint32_t **used, int *ref_status)
495 {
496         unsigned char (*sha1)[20] = info->shallow->sha1;
497         struct sha1_array *ref = info->ref;
498         unsigned int i, nr;
499         int *shallow, nr_shallow = 0;
500         struct paint_info pi;
501
502         trace_printf_key(TRACE_KEY, "shallow: assign_shallow_commits_to_refs\n");
503         shallow = xmalloc(sizeof(*shallow) * (info->nr_ours + info->nr_theirs));
504         for (i = 0; i < info->nr_ours; i++)
505                 shallow[nr_shallow++] = info->ours[i];
506         for (i = 0; i < info->nr_theirs; i++)
507                 shallow[nr_shallow++] = info->theirs[i];
508
509         /*
510          * Prepare the commit graph to track what refs can reach what
511          * (new) shallow commits.
512          */
513         nr = get_max_object_index();
514         for (i = 0; i < nr; i++) {
515                 struct object *o = get_indexed_object(i);
516                 if (!o || o->type != OBJ_COMMIT)
517                         continue;
518
519                 o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
520         }
521
522         memset(&pi, 0, sizeof(pi));
523         init_ref_bitmap(&pi.ref_bitmap);
524         pi.nr_bits = ref->nr;
525
526         /*
527          * "--not --all" to cut short the traversal if new refs
528          * connect to old refs. If not (e.g. force ref updates) it'll
529          * have to go down to the current shallow commits.
530          */
531         head_ref(mark_uninteresting, NULL);
532         for_each_ref(mark_uninteresting, NULL);
533
534         /* Mark potential bottoms so we won't go out of bound */
535         for (i = 0; i < nr_shallow; i++) {
536                 struct commit *c = lookup_commit(sha1[shallow[i]]);
537                 c->object.flags |= BOTTOM;
538         }
539
540         for (i = 0; i < ref->nr; i++)
541                 paint_down(&pi, ref->sha1[i], i);
542
543         if (used) {
544                 int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
545                 memset(used, 0, sizeof(*used) * info->shallow->nr);
546                 for (i = 0; i < nr_shallow; i++) {
547                         const struct commit *c = lookup_commit(sha1[shallow[i]]);
548                         uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
549                         if (*map)
550                                 used[shallow[i]] = xmemdupz(*map, bitmap_size);
551                 }
552                 /*
553                  * unreachable shallow commits are not removed from
554                  * "ours" and "theirs". The user is supposed to run
555                  * step 7 on every ref separately and not trust "ours"
556                  * and "theirs" any more.
557                  */
558         } else
559                 post_assign_shallow(info, &pi.ref_bitmap, ref_status);
560
561         clear_ref_bitmap(&pi.ref_bitmap);
562         for (i = 0; i < pi.slab_count; i++)
563                 free(pi.slab[i]);
564         free(pi.slab);
565         free(shallow);
566 }
567
568 struct commit_array {
569         struct commit **commits;
570         int nr, alloc;
571 };
572
573 static int add_ref(const char *refname,
574                    const unsigned char *sha1, int flags, void *cb_data)
575 {
576         struct commit_array *ca = cb_data;
577         ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
578         ca->commits[ca->nr] = lookup_commit_reference_gently(sha1, 1);
579         if (ca->commits[ca->nr])
580                 ca->nr++;
581         return 0;
582 }
583
584 static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
585 {
586         int i;
587         if (!ref_status)
588                 return;
589         for (i = 0; i < nr; i++)
590                 if (bitmap[i / 32] & (1 << (i % 32)))
591                         ref_status[i]++;
592 }
593
594 /*
595  * Step 7, reachability test on "ours" at commit level
596  */
597 static void post_assign_shallow(struct shallow_info *info,
598                                 struct ref_bitmap *ref_bitmap,
599                                 int *ref_status)
600 {
601         unsigned char (*sha1)[20] = info->shallow->sha1;
602         struct commit *c;
603         uint32_t **bitmap;
604         int dst, i, j;
605         int bitmap_nr = (info->ref->nr + 31) / 32;
606         struct commit_array ca;
607
608         trace_printf_key(TRACE_KEY, "shallow: post_assign_shallow\n");
609         if (ref_status)
610                 memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
611
612         /* Remove unreachable shallow commits from "theirs" */
613         for (i = dst = 0; i < info->nr_theirs; i++) {
614                 if (i != dst)
615                         info->theirs[dst] = info->theirs[i];
616                 c = lookup_commit(sha1[info->theirs[i]]);
617                 bitmap = ref_bitmap_at(ref_bitmap, c);
618                 if (!*bitmap)
619                         continue;
620                 for (j = 0; j < bitmap_nr; j++)
621                         if (bitmap[0][j]) {
622                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
623                                 dst++;
624                                 break;
625                         }
626         }
627         info->nr_theirs = dst;
628
629         memset(&ca, 0, sizeof(ca));
630         head_ref(add_ref, &ca);
631         for_each_ref(add_ref, &ca);
632
633         /* Remove unreachable shallow commits from "ours" */
634         for (i = dst = 0; i < info->nr_ours; i++) {
635                 if (i != dst)
636                         info->ours[dst] = info->ours[i];
637                 c = lookup_commit(sha1[info->ours[i]]);
638                 bitmap = ref_bitmap_at(ref_bitmap, c);
639                 if (!*bitmap)
640                         continue;
641                 for (j = 0; j < bitmap_nr; j++)
642                         if (bitmap[0][j] &&
643                             /* Step 7, reachability test at commit level */
644                             !in_merge_bases_many(c, ca.nr, ca.commits)) {
645                                 update_refstatus(ref_status, info->ref->nr, *bitmap);
646                                 dst++;
647                                 break;
648                         }
649         }
650         info->nr_ours = dst;
651
652         free(ca.commits);
653 }
654
655 /* (Delayed) step 7, reachability test at commit level */
656 int delayed_reachability_test(struct shallow_info *si, int c)
657 {
658         if (si->need_reachability_test[c]) {
659                 struct commit *commit = lookup_commit(si->shallow->sha1[c]);
660
661                 if (!si->commits) {
662                         struct commit_array ca;
663                         memset(&ca, 0, sizeof(ca));
664                         head_ref(add_ref, &ca);
665                         for_each_ref(add_ref, &ca);
666                         si->commits = ca.commits;
667                         si->nr_commits = ca.nr;
668                 }
669
670                 si->reachable[c] = in_merge_bases_many(commit,
671                                                        si->nr_commits,
672                                                        si->commits);
673                 si->need_reachability_test[c] = 0;
674         }
675         return si->reachable[c];
676 }