Thread-safe xmalloc and xrealloc needs a recursive mutex
[git/dscho.git] / commit.c
blob731191e63bd39a89a8ea4ed0390c49d5605cdbed
1 #include "cache.h"
2 #include "tag.h"
3 #include "commit.h"
4 #include "pkt-line.h"
5 #include "utf8.h"
6 #include "diff.h"
7 #include "revision.h"
8 #include "notes.h"
10 int save_commit_buffer = 1;
12 const char *commit_type = "commit";
14 static struct commit *check_commit(struct object *obj,
15                                    const unsigned char *sha1,
16                                    int quiet)
18         if (obj->type != OBJ_COMMIT) {
19                 if (!quiet)
20                         error("Object %s is a %s, not a commit",
21                               sha1_to_hex(sha1), typename(obj->type));
22                 return NULL;
23         }
24         return (struct commit *) obj;
27 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
28                                               int quiet)
30         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
32         if (!obj)
33                 return NULL;
34         return check_commit(obj, sha1, quiet);
37 struct commit *lookup_commit_reference(const unsigned char *sha1)
39         return lookup_commit_reference_gently(sha1, 0);
42 struct commit *lookup_commit(const unsigned char *sha1)
44         struct object *obj = lookup_object(sha1);
45         if (!obj)
46                 return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
47         if (!obj->type)
48                 obj->type = OBJ_COMMIT;
49         return check_commit(obj, sha1, 0);
52 static unsigned long parse_commit_date(const char *buf, const char *tail)
54         const char *dateptr;
56         if (buf + 6 >= tail)
57                 return 0;
58         if (memcmp(buf, "author", 6))
59                 return 0;
60         while (buf < tail && *buf++ != '\n')
61                 /* nada */;
62         if (buf + 9 >= tail)
63                 return 0;
64         if (memcmp(buf, "committer", 9))
65                 return 0;
66         while (buf < tail && *buf++ != '>')
67                 /* nada */;
68         if (buf >= tail)
69                 return 0;
70         dateptr = buf;
71         while (buf < tail && *buf++ != '\n')
72                 /* nada */;
73         if (buf >= tail)
74                 return 0;
75         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
76         return strtoul(dateptr, NULL, 10);
79 static struct commit_graft **commit_graft;
80 static int commit_graft_alloc, commit_graft_nr;
82 static int commit_graft_pos(const unsigned char *sha1)
84         int lo, hi;
85         lo = 0;
86         hi = commit_graft_nr;
87         while (lo < hi) {
88                 int mi = (lo + hi) / 2;
89                 struct commit_graft *graft = commit_graft[mi];
90                 int cmp = hashcmp(sha1, graft->sha1);
91                 if (!cmp)
92                         return mi;
93                 if (cmp < 0)
94                         hi = mi;
95                 else
96                         lo = mi + 1;
97         }
98         return -lo - 1;
101 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
103         int pos = commit_graft_pos(graft->sha1);
105         if (0 <= pos) {
106                 if (ignore_dups)
107                         free(graft);
108                 else {
109                         free(commit_graft[pos]);
110                         commit_graft[pos] = graft;
111                 }
112                 return 1;
113         }
114         pos = -pos - 1;
115         if (commit_graft_alloc <= ++commit_graft_nr) {
116                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
117                 commit_graft = xrealloc(commit_graft,
118                                         sizeof(*commit_graft) *
119                                         commit_graft_alloc);
120         }
121         if (pos < commit_graft_nr)
122                 memmove(commit_graft + pos + 1,
123                         commit_graft + pos,
124                         (commit_graft_nr - pos - 1) *
125                         sizeof(*commit_graft));
126         commit_graft[pos] = graft;
127         return 0;
130 struct commit_graft *read_graft_line(char *buf, int len)
132         /* The format is just "Commit Parent1 Parent2 ...\n" */
133         int i;
134         struct commit_graft *graft = NULL;
136         while (len && isspace(buf[len-1]))
137                 buf[--len] = '\0';
138         if (buf[0] == '#' || buf[0] == '\0')
139                 return NULL;
140         if ((len + 1) % 41) {
141         bad_graft_data:
142                 error("bad graft data: %s", buf);
143                 free(graft);
144                 return NULL;
145         }
146         i = (len + 1) / 41 - 1;
147         graft = xmalloc(sizeof(*graft) + 20 * i);
148         graft->nr_parent = i;
149         if (get_sha1_hex(buf, graft->sha1))
150                 goto bad_graft_data;
151         for (i = 40; i < len; i += 41) {
152                 if (buf[i] != ' ')
153                         goto bad_graft_data;
154                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
155                         goto bad_graft_data;
156         }
157         return graft;
160 static int read_graft_file(const char *graft_file)
162         FILE *fp = fopen(graft_file, "r");
163         char buf[1024];
164         if (!fp)
165                 return -1;
166         while (fgets(buf, sizeof(buf), fp)) {
167                 /* The format is just "Commit Parent1 Parent2 ...\n" */
168                 int len = strlen(buf);
169                 struct commit_graft *graft = read_graft_line(buf, len);
170                 if (!graft)
171                         continue;
172                 if (register_commit_graft(graft, 1))
173                         error("duplicate graft data: %s", buf);
174         }
175         fclose(fp);
176         return 0;
179 static void prepare_commit_graft(void)
181         static int commit_graft_prepared;
182         char *graft_file;
184         if (commit_graft_prepared)
185                 return;
186         graft_file = get_graft_file();
187         read_graft_file(graft_file);
188         /* make sure shallows are read */
189         is_repository_shallow();
190         commit_graft_prepared = 1;
193 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
195         int pos;
196         prepare_commit_graft();
197         pos = commit_graft_pos(sha1);
198         if (pos < 0)
199                 return NULL;
200         return commit_graft[pos];
203 int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
205         int i, count = 0;
206         for (i = 0; i < commit_graft_nr; i++)
207                 if (commit_graft[i]->nr_parent < 0) {
208                         const char *hex =
209                                 sha1_to_hex(commit_graft[i]->sha1);
210                         count++;
211                         if (use_pack_protocol)
212                                 packet_buf_write(out, "shallow %s", hex);
213                         else {
214                                 strbuf_addstr(out, hex);
215                                 strbuf_addch(out, '\n');
216                         }
217                 }
218         return count;
221 int unregister_shallow(const unsigned char *sha1)
223         int pos = commit_graft_pos(sha1);
224         if (pos < 0)
225                 return -1;
226         if (pos + 1 < commit_graft_nr)
227                 memmove(commit_graft + pos, commit_graft + pos + 1,
228                                 sizeof(struct commit_graft *)
229                                 * (commit_graft_nr - pos - 1));
230         commit_graft_nr--;
231         return 0;
234 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
236         char *tail = buffer;
237         char *bufptr = buffer;
238         unsigned char parent[20];
239         struct commit_list **pptr;
240         struct commit_graft *graft;
242         if (item->object.parsed)
243                 return 0;
244         item->object.parsed = 1;
245         tail += size;
246         if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
247                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
248         if (get_sha1_hex(bufptr + 5, parent) < 0)
249                 return error("bad tree pointer in commit %s",
250                              sha1_to_hex(item->object.sha1));
251         item->tree = lookup_tree(parent);
252         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
253         pptr = &item->parents;
255         graft = lookup_commit_graft(item->object.sha1);
256         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
257                 struct commit *new_parent;
259                 if (tail <= bufptr + 48 ||
260                     get_sha1_hex(bufptr + 7, parent) ||
261                     bufptr[47] != '\n')
262                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
263                 bufptr += 48;
264                 /*
265                  * The clone is shallow if nr_parent < 0, and we must
266                  * not traverse its real parents even when we unhide them.
267                  */
268                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
269                         continue;
270                 new_parent = lookup_commit(parent);
271                 if (new_parent)
272                         pptr = &commit_list_insert(new_parent, pptr)->next;
273         }
274         if (graft) {
275                 int i;
276                 struct commit *new_parent;
277                 for (i = 0; i < graft->nr_parent; i++) {
278                         new_parent = lookup_commit(graft->parent[i]);
279                         if (!new_parent)
280                                 continue;
281                         pptr = &commit_list_insert(new_parent, pptr)->next;
282                 }
283         }
284         item->date = parse_commit_date(bufptr, tail);
286         return 0;
289 int parse_commit(struct commit *item)
291         enum object_type type;
292         void *buffer;
293         unsigned long size;
294         int ret;
296         if (!item)
297                 return -1;
298         if (item->object.parsed)
299                 return 0;
300         buffer = read_sha1_file(item->object.sha1, &type, &size);
301         if (!buffer)
302                 return error("Could not read %s",
303                              sha1_to_hex(item->object.sha1));
304         if (type != OBJ_COMMIT) {
305                 free(buffer);
306                 return error("Object %s not a commit",
307                              sha1_to_hex(item->object.sha1));
308         }
309         ret = parse_commit_buffer(item, buffer, size);
310         if (save_commit_buffer && !ret) {
311                 item->buffer = buffer;
312                 return 0;
313         }
314         free(buffer);
315         return ret;
318 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
320         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
321         new_list->item = item;
322         new_list->next = *list_p;
323         *list_p = new_list;
324         return new_list;
327 unsigned commit_list_count(const struct commit_list *l)
329         unsigned c = 0;
330         for (; l; l = l->next )
331                 c++;
332         return c;
335 void free_commit_list(struct commit_list *list)
337         while (list) {
338                 struct commit_list *temp = list;
339                 list = temp->next;
340                 free(temp);
341         }
344 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
346         struct commit_list **pp = list;
347         struct commit_list *p;
348         while ((p = *pp) != NULL) {
349                 if (p->item->date < item->date) {
350                         break;
351                 }
352                 pp = &p->next;
353         }
354         return commit_list_insert(item, pp);
358 void sort_by_date(struct commit_list **list)
360         struct commit_list *ret = NULL;
361         while (*list) {
362                 insert_by_date((*list)->item, &ret);
363                 *list = (*list)->next;
364         }
365         *list = ret;
368 struct commit *pop_most_recent_commit(struct commit_list **list,
369                                       unsigned int mark)
371         struct commit *ret = (*list)->item;
372         struct commit_list *parents = ret->parents;
373         struct commit_list *old = *list;
375         *list = (*list)->next;
376         free(old);
378         while (parents) {
379                 struct commit *commit = parents->item;
380                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
381                         commit->object.flags |= mark;
382                         insert_by_date(commit, list);
383                 }
384                 parents = parents->next;
385         }
386         return ret;
389 void clear_commit_marks(struct commit *commit, unsigned int mark)
391         while (commit) {
392                 struct commit_list *parents;
394                 if (!(mark & commit->object.flags))
395                         return;
397                 commit->object.flags &= ~mark;
399                 parents = commit->parents;
400                 if (!parents)
401                         return;
403                 while ((parents = parents->next))
404                         clear_commit_marks(parents->item, mark);
406                 commit = commit->parents->item;
407         }
410 struct commit *pop_commit(struct commit_list **stack)
412         struct commit_list *top = *stack;
413         struct commit *item = top ? top->item : NULL;
415         if (top) {
416                 *stack = top->next;
417                 free(top);
418         }
419         return item;
423  * Performs an in-place topological sort on the list supplied.
424  */
425 void sort_in_topological_order(struct commit_list ** list, int lifo)
427         struct commit_list *next, *orig = *list;
428         struct commit_list *work, **insert;
429         struct commit_list **pptr;
431         if (!orig)
432                 return;
433         *list = NULL;
435         /* Mark them and clear the indegree */
436         for (next = orig; next; next = next->next) {
437                 struct commit *commit = next->item;
438                 commit->indegree = 1;
439         }
441         /* update the indegree */
442         for (next = orig; next; next = next->next) {
443                 struct commit_list * parents = next->item->parents;
444                 while (parents) {
445                         struct commit *parent = parents->item;
447                         if (parent->indegree)
448                                 parent->indegree++;
449                         parents = parents->next;
450                 }
451         }
453         /*
454          * find the tips
455          *
456          * tips are nodes not reachable from any other node in the list
457          *
458          * the tips serve as a starting set for the work queue.
459          */
460         work = NULL;
461         insert = &work;
462         for (next = orig; next; next = next->next) {
463                 struct commit *commit = next->item;
465                 if (commit->indegree == 1)
466                         insert = &commit_list_insert(commit, insert)->next;
467         }
469         /* process the list in topological order */
470         if (!lifo)
471                 sort_by_date(&work);
473         pptr = list;
474         *list = NULL;
475         while (work) {
476                 struct commit *commit;
477                 struct commit_list *parents, *work_item;
479                 work_item = work;
480                 work = work_item->next;
481                 work_item->next = NULL;
483                 commit = work_item->item;
484                 for (parents = commit->parents; parents ; parents = parents->next) {
485                         struct commit *parent=parents->item;
487                         if (!parent->indegree)
488                                 continue;
490                         /*
491                          * parents are only enqueued for emission
492                          * when all their children have been emitted thereby
493                          * guaranteeing topological order.
494                          */
495                         if (--parent->indegree == 1) {
496                                 if (!lifo)
497                                         insert_by_date(parent, &work);
498                                 else
499                                         commit_list_insert(parent, &work);
500                         }
501                 }
502                 /*
503                  * work_item is a commit all of whose children
504                  * have already been emitted. we can emit it now.
505                  */
506                 commit->indegree = 0;
507                 *pptr = work_item;
508                 pptr = &work_item->next;
509         }
512 /* merge-base stuff */
514 /* bits #0..15 in revision.h */
515 #define PARENT1         (1u<<16)
516 #define PARENT2         (1u<<17)
517 #define STALE           (1u<<18)
518 #define RESULT          (1u<<19)
520 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
522 static struct commit *interesting(struct commit_list *list)
524         while (list) {
525                 struct commit *commit = list->item;
526                 list = list->next;
527                 if (commit->object.flags & STALE)
528                         continue;
529                 return commit;
530         }
531         return NULL;
534 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
536         struct commit_list *list = NULL;
537         struct commit_list *result = NULL;
538         int i;
540         for (i = 0; i < n; i++) {
541                 if (one == twos[i])
542                         /*
543                          * We do not mark this even with RESULT so we do not
544                          * have to clean it up.
545                          */
546                         return commit_list_insert(one, &result);
547         }
549         if (parse_commit(one))
550                 return NULL;
551         for (i = 0; i < n; i++) {
552                 if (parse_commit(twos[i]))
553                         return NULL;
554         }
556         one->object.flags |= PARENT1;
557         insert_by_date(one, &list);
558         for (i = 0; i < n; i++) {
559                 twos[i]->object.flags |= PARENT2;
560                 insert_by_date(twos[i], &list);
561         }
563         while (interesting(list)) {
564                 struct commit *commit;
565                 struct commit_list *parents;
566                 struct commit_list *next;
567                 int flags;
569                 commit = list->item;
570                 next = list->next;
571                 free(list);
572                 list = next;
574                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
575                 if (flags == (PARENT1 | PARENT2)) {
576                         if (!(commit->object.flags & RESULT)) {
577                                 commit->object.flags |= RESULT;
578                                 insert_by_date(commit, &result);
579                         }
580                         /* Mark parents of a found merge stale */
581                         flags |= STALE;
582                 }
583                 parents = commit->parents;
584                 while (parents) {
585                         struct commit *p = parents->item;
586                         parents = parents->next;
587                         if ((p->object.flags & flags) == flags)
588                                 continue;
589                         if (parse_commit(p))
590                                 return NULL;
591                         p->object.flags |= flags;
592                         insert_by_date(p, &list);
593                 }
594         }
596         /* Clean up the result to remove stale ones */
597         free_commit_list(list);
598         list = result; result = NULL;
599         while (list) {
600                 struct commit_list *next = list->next;
601                 if (!(list->item->object.flags & STALE))
602                         insert_by_date(list->item, &result);
603                 free(list);
604                 list = next;
605         }
606         return result;
609 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
611         struct commit_list *i, *j, *k, *ret = NULL;
612         struct commit_list **pptr = &ret;
614         for (i = in; i; i = i->next) {
615                 if (!ret)
616                         pptr = &commit_list_insert(i->item, pptr)->next;
617                 else {
618                         struct commit_list *new = NULL, *end = NULL;
620                         for (j = ret; j; j = j->next) {
621                                 struct commit_list *bases;
622                                 bases = get_merge_bases(i->item, j->item, 1);
623                                 if (!new)
624                                         new = bases;
625                                 else
626                                         end->next = bases;
627                                 for (k = bases; k; k = k->next)
628                                         end = k;
629                         }
630                         ret = new;
631                 }
632         }
633         return ret;
636 struct commit_list *get_merge_bases_many(struct commit *one,
637                                          int n,
638                                          struct commit **twos,
639                                          int cleanup)
641         struct commit_list *list;
642         struct commit **rslt;
643         struct commit_list *result;
644         int cnt, i, j;
646         result = merge_bases_many(one, n, twos);
647         for (i = 0; i < n; i++) {
648                 if (one == twos[i])
649                         return result;
650         }
651         if (!result || !result->next) {
652                 if (cleanup) {
653                         clear_commit_marks(one, all_flags);
654                         for (i = 0; i < n; i++)
655                                 clear_commit_marks(twos[i], all_flags);
656                 }
657                 return result;
658         }
660         /* There are more than one */
661         cnt = 0;
662         list = result;
663         while (list) {
664                 list = list->next;
665                 cnt++;
666         }
667         rslt = xcalloc(cnt, sizeof(*rslt));
668         for (list = result, i = 0; list; list = list->next)
669                 rslt[i++] = list->item;
670         free_commit_list(result);
672         clear_commit_marks(one, all_flags);
673         for (i = 0; i < n; i++)
674                 clear_commit_marks(twos[i], all_flags);
675         for (i = 0; i < cnt - 1; i++) {
676                 for (j = i+1; j < cnt; j++) {
677                         if (!rslt[i] || !rslt[j])
678                                 continue;
679                         result = merge_bases_many(rslt[i], 1, &rslt[j]);
680                         clear_commit_marks(rslt[i], all_flags);
681                         clear_commit_marks(rslt[j], all_flags);
682                         for (list = result; list; list = list->next) {
683                                 if (rslt[i] == list->item)
684                                         rslt[i] = NULL;
685                                 if (rslt[j] == list->item)
686                                         rslt[j] = NULL;
687                         }
688                 }
689         }
691         /* Surviving ones in rslt[] are the independent results */
692         result = NULL;
693         for (i = 0; i < cnt; i++) {
694                 if (rslt[i])
695                         insert_by_date(rslt[i], &result);
696         }
697         free(rslt);
698         return result;
701 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
702                                     int cleanup)
704         return get_merge_bases_many(one, 1, &two, cleanup);
707 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
709         if (!with_commit)
710                 return 1;
711         while (with_commit) {
712                 struct commit *other;
714                 other = with_commit->item;
715                 with_commit = with_commit->next;
716                 if (in_merge_bases(other, &commit, 1))
717                         return 1;
718         }
719         return 0;
722 int in_merge_bases(struct commit *commit, struct commit **reference, int num)
724         struct commit_list *bases, *b;
725         int ret = 0;
727         if (num == 1)
728                 bases = get_merge_bases(commit, *reference, 1);
729         else
730                 die("not yet");
731         for (b = bases; b; b = b->next) {
732                 if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
733                         ret = 1;
734                         break;
735                 }
736         }
738         free_commit_list(bases);
739         return ret;
742 struct commit_list *reduce_heads(struct commit_list *heads)
744         struct commit_list *p;
745         struct commit_list *result = NULL, **tail = &result;
746         struct commit **other;
747         size_t num_head, num_other;
749         if (!heads)
750                 return NULL;
752         /* Avoid unnecessary reallocations */
753         for (p = heads, num_head = 0; p; p = p->next)
754                 num_head++;
755         other = xcalloc(sizeof(*other), num_head);
757         /* For each commit, see if it can be reached by others */
758         for (p = heads; p; p = p->next) {
759                 struct commit_list *q, *base;
761                 /* Do we already have this in the result? */
762                 for (q = result; q; q = q->next)
763                         if (p->item == q->item)
764                                 break;
765                 if (q)
766                         continue;
768                 num_other = 0;
769                 for (q = heads; q; q = q->next) {
770                         if (p->item == q->item)
771                                 continue;
772                         other[num_other++] = q->item;
773                 }
774                 if (num_other)
775                         base = get_merge_bases_many(p->item, num_other, other, 1);
776                 else
777                         base = NULL;
778                 /*
779                  * If p->item does not have anything common with other
780                  * commits, there won't be any merge base.  If it is
781                  * reachable from some of the others, p->item will be
782                  * the merge base.  If its history is connected with
783                  * others, but p->item is not reachable by others, we
784                  * will get something other than p->item back.
785                  */
786                 if (!base || (base->item != p->item))
787                         tail = &(commit_list_insert(p->item, tail)->next);
788                 free_commit_list(base);
789         }
790         free(other);
791         return result;