use write_str_in_full helper to avoid literal string lengths
[git/git.git] / commit.c
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
9 int save_commit_buffer = 1;
10
11 const char *commit_type = "commit";
12
13 static struct commit *check_commit(struct object *obj,
14 const unsigned char *sha1,
15 int quiet)
16 {
17 if (obj->type != OBJ_COMMIT) {
18 if (!quiet)
19 error("Object %s is a %s, not a commit",
20 sha1_to_hex(sha1), typename(obj->type));
21 return NULL;
22 }
23 return (struct commit *) obj;
24 }
25
26 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
27 int quiet)
28 {
29 struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
30
31 if (!obj)
32 return NULL;
33 return check_commit(obj, sha1, quiet);
34 }
35
36 struct commit *lookup_commit_reference(const unsigned char *sha1)
37 {
38 return lookup_commit_reference_gently(sha1, 0);
39 }
40
41 struct commit *lookup_commit(const unsigned char *sha1)
42 {
43 struct object *obj = lookup_object(sha1);
44 if (!obj)
45 return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
46 if (!obj->type)
47 obj->type = OBJ_COMMIT;
48 return check_commit(obj, sha1, 0);
49 }
50
51 static unsigned long parse_commit_date(const char *buf, const char *tail)
52 {
53 const char *dateptr;
54
55 if (buf + 6 >= tail)
56 return 0;
57 if (memcmp(buf, "author", 6))
58 return 0;
59 while (buf < tail && *buf++ != '\n')
60 /* nada */;
61 if (buf + 9 >= tail)
62 return 0;
63 if (memcmp(buf, "committer", 9))
64 return 0;
65 while (buf < tail && *buf++ != '>')
66 /* nada */;
67 if (buf >= tail)
68 return 0;
69 dateptr = buf;
70 while (buf < tail && *buf++ != '\n')
71 /* nada */;
72 if (buf >= tail)
73 return 0;
74 /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
75 return strtoul(dateptr, NULL, 10);
76 }
77
78 static struct commit_graft **commit_graft;
79 static int commit_graft_alloc, commit_graft_nr;
80
81 static int commit_graft_pos(const unsigned char *sha1)
82 {
83 int lo, hi;
84 lo = 0;
85 hi = commit_graft_nr;
86 while (lo < hi) {
87 int mi = (lo + hi) / 2;
88 struct commit_graft *graft = commit_graft[mi];
89 int cmp = hashcmp(sha1, graft->sha1);
90 if (!cmp)
91 return mi;
92 if (cmp < 0)
93 hi = mi;
94 else
95 lo = mi + 1;
96 }
97 return -lo - 1;
98 }
99
100 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
101 {
102 int pos = commit_graft_pos(graft->sha1);
103
104 if (0 <= pos) {
105 if (ignore_dups)
106 free(graft);
107 else {
108 free(commit_graft[pos]);
109 commit_graft[pos] = graft;
110 }
111 return 1;
112 }
113 pos = -pos - 1;
114 if (commit_graft_alloc <= ++commit_graft_nr) {
115 commit_graft_alloc = alloc_nr(commit_graft_alloc);
116 commit_graft = xrealloc(commit_graft,
117 sizeof(*commit_graft) *
118 commit_graft_alloc);
119 }
120 if (pos < commit_graft_nr)
121 memmove(commit_graft + pos + 1,
122 commit_graft + pos,
123 (commit_graft_nr - pos - 1) *
124 sizeof(*commit_graft));
125 commit_graft[pos] = graft;
126 return 0;
127 }
128
129 struct commit_graft *read_graft_line(char *buf, int len)
130 {
131 /* The format is just "Commit Parent1 Parent2 ...\n" */
132 int i;
133 struct commit_graft *graft = NULL;
134
135 if (buf[len-1] == '\n')
136 buf[--len] = 0;
137 if (buf[0] == '#' || buf[0] == '\0')
138 return NULL;
139 if ((len + 1) % 41) {
140 bad_graft_data:
141 error("bad graft data: %s", buf);
142 free(graft);
143 return NULL;
144 }
145 i = (len + 1) / 41 - 1;
146 graft = xmalloc(sizeof(*graft) + 20 * i);
147 graft->nr_parent = i;
148 if (get_sha1_hex(buf, graft->sha1))
149 goto bad_graft_data;
150 for (i = 40; i < len; i += 41) {
151 if (buf[i] != ' ')
152 goto bad_graft_data;
153 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
154 goto bad_graft_data;
155 }
156 return graft;
157 }
158
159 static int read_graft_file(const char *graft_file)
160 {
161 FILE *fp = fopen(graft_file, "r");
162 char buf[1024];
163 if (!fp)
164 return -1;
165 while (fgets(buf, sizeof(buf), fp)) {
166 /* The format is just "Commit Parent1 Parent2 ...\n" */
167 int len = strlen(buf);
168 struct commit_graft *graft = read_graft_line(buf, len);
169 if (!graft)
170 continue;
171 if (register_commit_graft(graft, 1))
172 error("duplicate graft data: %s", buf);
173 }
174 fclose(fp);
175 return 0;
176 }
177
178 static void prepare_commit_graft(void)
179 {
180 static int commit_graft_prepared;
181 char *graft_file;
182
183 if (commit_graft_prepared)
184 return;
185 graft_file = get_graft_file();
186 read_graft_file(graft_file);
187 /* make sure shallows are read */
188 is_repository_shallow();
189 commit_graft_prepared = 1;
190 }
191
192 struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
193 {
194 int pos;
195 prepare_commit_graft();
196 pos = commit_graft_pos(sha1);
197 if (pos < 0)
198 return NULL;
199 return commit_graft[pos];
200 }
201
202 int write_shallow_commits(int fd, int use_pack_protocol)
203 {
204 int i, count = 0;
205 for (i = 0; i < commit_graft_nr; i++)
206 if (commit_graft[i]->nr_parent < 0) {
207 const char *hex =
208 sha1_to_hex(commit_graft[i]->sha1);
209 count++;
210 if (use_pack_protocol)
211 packet_write(fd, "shallow %s", hex);
212 else {
213 if (write_in_full(fd, hex, 40) != 40)
214 break;
215 if (write_str_in_full(fd, "\n") != 1)
216 break;
217 }
218 }
219 return count;
220 }
221
222 int unregister_shallow(const unsigned char *sha1)
223 {
224 int pos = commit_graft_pos(sha1);
225 if (pos < 0)
226 return -1;
227 if (pos + 1 < commit_graft_nr)
228 memcpy(commit_graft + pos, commit_graft + pos + 1,
229 sizeof(struct commit_graft *)
230 * (commit_graft_nr - pos - 1));
231 commit_graft_nr--;
232 return 0;
233 }
234
235 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
236 {
237 char *tail = buffer;
238 char *bufptr = buffer;
239 unsigned char parent[20];
240 struct commit_list **pptr;
241 struct commit_graft *graft;
242
243 if (item->object.parsed)
244 return 0;
245 item->object.parsed = 1;
246 tail += size;
247 if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
248 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
249 if (get_sha1_hex(bufptr + 5, parent) < 0)
250 return error("bad tree pointer in commit %s",
251 sha1_to_hex(item->object.sha1));
252 item->tree = lookup_tree(parent);
253 bufptr += 46; /* "tree " + "hex sha1" + "\n" */
254 pptr = &item->parents;
255
256 graft = lookup_commit_graft(item->object.sha1);
257 while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
258 struct commit *new_parent;
259
260 if (tail <= bufptr + 48 ||
261 get_sha1_hex(bufptr + 7, parent) ||
262 bufptr[47] != '\n')
263 return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
264 bufptr += 48;
265 /*
266 * The clone is shallow if nr_parent < 0, and we must
267 * not traverse its real parents even when we unhide them.
268 */
269 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
270 continue;
271 new_parent = lookup_commit(parent);
272 if (new_parent)
273 pptr = &commit_list_insert(new_parent, pptr)->next;
274 }
275 if (graft) {
276 int i;
277 struct commit *new_parent;
278 for (i = 0; i < graft->nr_parent; i++) {
279 new_parent = lookup_commit(graft->parent[i]);
280 if (!new_parent)
281 continue;
282 pptr = &commit_list_insert(new_parent, pptr)->next;
283 }
284 }
285 item->date = parse_commit_date(bufptr, tail);
286
287 return 0;
288 }
289
290 int parse_commit(struct commit *item)
291 {
292 enum object_type type;
293 void *buffer;
294 unsigned long size;
295 int ret;
296
297 if (!item)
298 return -1;
299 if (item->object.parsed)
300 return 0;
301 buffer = read_sha1_file(item->object.sha1, &type, &size);
302 if (!buffer)
303 return error("Could not read %s",
304 sha1_to_hex(item->object.sha1));
305 if (type != OBJ_COMMIT) {
306 free(buffer);
307 return error("Object %s not a commit",
308 sha1_to_hex(item->object.sha1));
309 }
310 ret = parse_commit_buffer(item, buffer, size);
311 if (save_commit_buffer && !ret) {
312 item->buffer = buffer;
313 return 0;
314 }
315 free(buffer);
316 return ret;
317 }
318
319 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
320 {
321 struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
322 new_list->item = item;
323 new_list->next = *list_p;
324 *list_p = new_list;
325 return new_list;
326 }
327
328 unsigned commit_list_count(const struct commit_list *l)
329 {
330 unsigned c = 0;
331 for (; l; l = l->next )
332 c++;
333 return c;
334 }
335
336 void free_commit_list(struct commit_list *list)
337 {
338 while (list) {
339 struct commit_list *temp = list;
340 list = temp->next;
341 free(temp);
342 }
343 }
344
345 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
346 {
347 struct commit_list **pp = list;
348 struct commit_list *p;
349 while ((p = *pp) != NULL) {
350 if (p->item->date < item->date) {
351 break;
352 }
353 pp = &p->next;
354 }
355 return commit_list_insert(item, pp);
356 }
357
358
359 void sort_by_date(struct commit_list **list)
360 {
361 struct commit_list *ret = NULL;
362 while (*list) {
363 insert_by_date((*list)->item, &ret);
364 *list = (*list)->next;
365 }
366 *list = ret;
367 }
368
369 struct commit *pop_most_recent_commit(struct commit_list **list,
370 unsigned int mark)
371 {
372 struct commit *ret = (*list)->item;
373 struct commit_list *parents = ret->parents;
374 struct commit_list *old = *list;
375
376 *list = (*list)->next;
377 free(old);
378
379 while (parents) {
380 struct commit *commit = parents->item;
381 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
382 commit->object.flags |= mark;
383 insert_by_date(commit, list);
384 }
385 parents = parents->next;
386 }
387 return ret;
388 }
389
390 void clear_commit_marks(struct commit *commit, unsigned int mark)
391 {
392 while (commit) {
393 struct commit_list *parents;
394
395 if (!(mark & commit->object.flags))
396 return;
397
398 commit->object.flags &= ~mark;
399
400 parents = commit->parents;
401 if (!parents)
402 return;
403
404 while ((parents = parents->next))
405 clear_commit_marks(parents->item, mark);
406
407 commit = commit->parents->item;
408 }
409 }
410
411 struct commit *pop_commit(struct commit_list **stack)
412 {
413 struct commit_list *top = *stack;
414 struct commit *item = top ? top->item : NULL;
415
416 if (top) {
417 *stack = top->next;
418 free(top);
419 }
420 return item;
421 }
422
423 /*
424 * Performs an in-place topological sort on the list supplied.
425 */
426 void sort_in_topological_order(struct commit_list ** list, int lifo)
427 {
428 struct commit_list *next, *orig = *list;
429 struct commit_list *work, **insert;
430 struct commit_list **pptr;
431
432 if (!orig)
433 return;
434 *list = NULL;
435
436 /* Mark them and clear the indegree */
437 for (next = orig; next; next = next->next) {
438 struct commit *commit = next->item;
439 commit->indegree = 1;
440 }
441
442 /* update the indegree */
443 for (next = orig; next; next = next->next) {
444 struct commit_list * parents = next->item->parents;
445 while (parents) {
446 struct commit *parent = parents->item;
447
448 if (parent->indegree)
449 parent->indegree++;
450 parents = parents->next;
451 }
452 }
453
454 /*
455 * find the tips
456 *
457 * tips are nodes not reachable from any other node in the list
458 *
459 * the tips serve as a starting set for the work queue.
460 */
461 work = NULL;
462 insert = &work;
463 for (next = orig; next; next = next->next) {
464 struct commit *commit = next->item;
465
466 if (commit->indegree == 1)
467 insert = &commit_list_insert(commit, insert)->next;
468 }
469
470 /* process the list in topological order */
471 if (!lifo)
472 sort_by_date(&work);
473
474 pptr = list;
475 *list = NULL;
476 while (work) {
477 struct commit *commit;
478 struct commit_list *parents, *work_item;
479
480 work_item = work;
481 work = work_item->next;
482 work_item->next = NULL;
483
484 commit = work_item->item;
485 for (parents = commit->parents; parents ; parents = parents->next) {
486 struct commit *parent=parents->item;
487
488 if (!parent->indegree)
489 continue;
490
491 /*
492 * parents are only enqueued for emission
493 * when all their children have been emitted thereby
494 * guaranteeing topological order.
495 */
496 if (--parent->indegree == 1) {
497 if (!lifo)
498 insert_by_date(parent, &work);
499 else
500 commit_list_insert(parent, &work);
501 }
502 }
503 /*
504 * work_item is a commit all of whose children
505 * have already been emitted. we can emit it now.
506 */
507 commit->indegree = 0;
508 *pptr = work_item;
509 pptr = &work_item->next;
510 }
511 }
512
513 /* merge-base stuff */
514
515 /* bits #0..15 in revision.h */
516 #define PARENT1 (1u<<16)
517 #define PARENT2 (1u<<17)
518 #define STALE (1u<<18)
519 #define RESULT (1u<<19)
520
521 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
522
523 static struct commit *interesting(struct commit_list *list)
524 {
525 while (list) {
526 struct commit *commit = list->item;
527 list = list->next;
528 if (commit->object.flags & STALE)
529 continue;
530 return commit;
531 }
532 return NULL;
533 }
534
535 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
536 {
537 struct commit_list *list = NULL;
538 struct commit_list *result = NULL;
539 int i;
540
541 for (i = 0; i < n; i++) {
542 if (one == twos[i])
543 /*
544 * We do not mark this even with RESULT so we do not
545 * have to clean it up.
546 */
547 return commit_list_insert(one, &result);
548 }
549
550 if (parse_commit(one))
551 return NULL;
552 for (i = 0; i < n; i++) {
553 if (parse_commit(twos[i]))
554 return NULL;
555 }
556
557 one->object.flags |= PARENT1;
558 insert_by_date(one, &list);
559 for (i = 0; i < n; i++) {
560 twos[i]->object.flags |= PARENT2;
561 insert_by_date(twos[i], &list);
562 }
563
564 while (interesting(list)) {
565 struct commit *commit;
566 struct commit_list *parents;
567 struct commit_list *next;
568 int flags;
569
570 commit = list->item;
571 next = list->next;
572 free(list);
573 list = next;
574
575 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
576 if (flags == (PARENT1 | PARENT2)) {
577 if (!(commit->object.flags & RESULT)) {
578 commit->object.flags |= RESULT;
579 insert_by_date(commit, &result);
580 }
581 /* Mark parents of a found merge stale */
582 flags |= STALE;
583 }
584 parents = commit->parents;
585 while (parents) {
586 struct commit *p = parents->item;
587 parents = parents->next;
588 if ((p->object.flags & flags) == flags)
589 continue;
590 if (parse_commit(p))
591 return NULL;
592 p->object.flags |= flags;
593 insert_by_date(p, &list);
594 }
595 }
596
597 /* Clean up the result to remove stale ones */
598 free_commit_list(list);
599 list = result; result = NULL;
600 while (list) {
601 struct commit_list *next = list->next;
602 if (!(list->item->object.flags & STALE))
603 insert_by_date(list->item, &result);
604 free(list);
605 list = next;
606 }
607 return result;
608 }
609
610 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
611 {
612 struct commit_list *i, *j, *k, *ret = NULL;
613 struct commit_list **pptr = &ret;
614
615 for (i = in; i; i = i->next) {
616 if (!ret)
617 pptr = &commit_list_insert(i->item, pptr)->next;
618 else {
619 struct commit_list *new = NULL, *end = NULL;
620
621 for (j = ret; j; j = j->next) {
622 struct commit_list *bases;
623 bases = get_merge_bases(i->item, j->item, 1);
624 if (!new)
625 new = bases;
626 else
627 end->next = bases;
628 for (k = bases; k; k = k->next)
629 end = k;
630 }
631 ret = new;
632 }
633 }
634 return ret;
635 }
636
637 struct commit_list *get_merge_bases_many(struct commit *one,
638 int n,
639 struct commit **twos,
640 int cleanup)
641 {
642 struct commit_list *list;
643 struct commit **rslt;
644 struct commit_list *result;
645 int cnt, i, j;
646
647 result = merge_bases_many(one, n, twos);
648 for (i = 0; i < n; i++) {
649 if (one == twos[i])
650 return result;
651 }
652 if (!result || !result->next) {
653 if (cleanup) {
654 clear_commit_marks(one, all_flags);
655 for (i = 0; i < n; i++)
656 clear_commit_marks(twos[i], all_flags);
657 }
658 return result;
659 }
660
661 /* There are more than one */
662 cnt = 0;
663 list = result;
664 while (list) {
665 list = list->next;
666 cnt++;
667 }
668 rslt = xcalloc(cnt, sizeof(*rslt));
669 for (list = result, i = 0; list; list = list->next)
670 rslt[i++] = list->item;
671 free_commit_list(result);
672
673 clear_commit_marks(one, all_flags);
674 for (i = 0; i < n; i++)
675 clear_commit_marks(twos[i], all_flags);
676 for (i = 0; i < cnt - 1; i++) {
677 for (j = i+1; j < cnt; j++) {
678 if (!rslt[i] || !rslt[j])
679 continue;
680 result = merge_bases_many(rslt[i], 1, &rslt[j]);
681 clear_commit_marks(rslt[i], all_flags);
682 clear_commit_marks(rslt[j], all_flags);
683 for (list = result; list; list = list->next) {
684 if (rslt[i] == list->item)
685 rslt[i] = NULL;
686 if (rslt[j] == list->item)
687 rslt[j] = NULL;
688 }
689 }
690 }
691
692 /* Surviving ones in rslt[] are the independent results */
693 result = NULL;
694 for (i = 0; i < cnt; i++) {
695 if (rslt[i])
696 insert_by_date(rslt[i], &result);
697 }
698 free(rslt);
699 return result;
700 }
701
702 struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
703 int cleanup)
704 {
705 return get_merge_bases_many(one, 1, &two, cleanup);
706 }
707
708 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
709 {
710 if (!with_commit)
711 return 1;
712 while (with_commit) {
713 struct commit *other;
714
715 other = with_commit->item;
716 with_commit = with_commit->next;
717 if (in_merge_bases(other, &commit, 1))
718 return 1;
719 }
720 return 0;
721 }
722
723 int in_merge_bases(struct commit *commit, struct commit **reference, int num)
724 {
725 struct commit_list *bases, *b;
726 int ret = 0;
727
728 if (num == 1)
729 bases = get_merge_bases(commit, *reference, 1);
730 else
731 die("not yet");
732 for (b = bases; b; b = b->next) {
733 if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
734 ret = 1;
735 break;
736 }
737 }
738
739 free_commit_list(bases);
740 return ret;
741 }
742
743 struct commit_list *reduce_heads(struct commit_list *heads)
744 {
745 struct commit_list *p;
746 struct commit_list *result = NULL, **tail = &result;
747 struct commit **other;
748 size_t num_head, num_other;
749
750 if (!heads)
751 return NULL;
752
753 /* Avoid unnecessary reallocations */
754 for (p = heads, num_head = 0; p; p = p->next)
755 num_head++;
756 other = xcalloc(sizeof(*other), num_head);
757
758 /* For each commit, see if it can be reached by others */
759 for (p = heads; p; p = p->next) {
760 struct commit_list *q, *base;
761
762 /* Do we already have this in the result? */
763 for (q = result; q; q = q->next)
764 if (p->item == q->item)
765 break;
766 if (q)
767 continue;
768
769 num_other = 0;
770 for (q = heads; q; q = q->next) {
771 if (p->item == q->item)
772 continue;
773 other[num_other++] = q->item;
774 }
775 if (num_other)
776 base = get_merge_bases_many(p->item, num_other, other, 1);
777 else
778 base = NULL;
779 /*
780 * If p->item does not have anything common with other
781 * commits, there won't be any merge base. If it is
782 * reachable from some of the others, p->item will be
783 * the merge base. If its history is connected with
784 * others, but p->item is not reachable by others, we
785 * will get something other than p->item back.
786 */
787 if (!base || (base->item != p->item))
788 tail = &(commit_list_insert(p->item, tail)->next);
789 free_commit_list(base);
790 }
791 free(other);
792 return result;
793 }