CVS-like push-pull description update.
[git.git] / merge-base.c
blob591956666d06603d145ac9a5d2102185289e4c2c
1 #include <stdlib.h>
2 #include "cache.h"
3 #include "commit.h"
5 static struct commit *common_ancestor(struct commit *rev1, struct commit *rev2)
7 struct commit_list *list = NULL;
8 struct commit_list *result = NULL;
10 if (rev1 == rev2)
11 return rev1;
13 parse_commit(rev1);
14 parse_commit(rev2);
16 rev1->object.flags |= 1;
17 rev2->object.flags |= 2;
18 insert_by_date(rev1, &list);
19 insert_by_date(rev2, &list);
21 while (list) {
22 struct commit *commit = list->item;
23 struct commit_list *tmp = list, *parents;
24 int flags = commit->object.flags & 3;
26 list = list->next;
27 free(tmp);
28 switch (flags) {
29 case 3:
30 insert_by_date(commit, &result);
31 continue;
32 case 0:
33 die("git-merge-base: commit without either parent?");
35 parents = commit->parents;
36 while (parents) {
37 struct commit *p = parents->item;
38 parents = parents->next;
39 if ((p->object.flags & flags) == flags)
40 continue;
41 parse_commit(p);
42 p->object.flags |= flags;
43 insert_by_date(p, &list);
46 if (!result)
47 return NULL;
48 return result->item;
51 int main(int argc, char **argv)
53 struct commit *rev1, *rev2, *ret;
54 unsigned char rev1key[20], rev2key[20];
56 if (argc != 3 ||
57 get_sha1(argv[1], rev1key) ||
58 get_sha1(argv[2], rev2key)) {
59 usage("git-merge-base <commit-id> <commit-id>");
61 rev1 = lookup_commit_reference(rev1key);
62 rev2 = lookup_commit_reference(rev2key);
63 if (!rev1 || !rev2)
64 return 1;
65 ret = common_ancestor(rev1, rev2);
66 if (!ret)
67 return 1;
68 printf("%s\n", sha1_to_hex(ret->object.sha1));
69 return 0;