git-commit-vandalism/merge-base.c
Linus Torvalds 3c249c9506 Add "get_sha1()" helper function.
This allows the programs to use various simplified versions of
the SHA1 names, eg just say "HEAD" for the SHA1 pointed to by
the .git/HEAD file etc.

For example, this commit has been done with

	git-commit-tree $(git-write-tree) -p HEAD

instead of the traditional "$(cat .git/HEAD)" syntax.
2005-05-01 16:36:56 -07:00

73 lines
1.6 KiB
C

#include <stdlib.h>
#include "cache.h"
#include "commit.h"
static struct commit *process_list(struct commit_list **list_p, int this_mark,
int other_mark)
{
struct commit *item = (*list_p)->item;
if (item->object.flags & other_mark) {
return item;
} else {
pop_most_recent_commit(list_p, this_mark);
}
return NULL;
}
struct commit *common_ancestor(struct commit *rev1, struct commit *rev2)
{
struct commit_list *rev1list = NULL;
struct commit_list *rev2list = NULL;
commit_list_insert(rev1, &rev1list);
rev1->object.flags |= 0x1;
commit_list_insert(rev2, &rev2list);
rev2->object.flags |= 0x2;
parse_commit(rev1);
parse_commit(rev2);
while (rev1list || rev2list) {
struct commit *ret;
if (!rev1list) {
// process 2
ret = process_list(&rev2list, 0x2, 0x1);
} else if (!rev2list) {
// process 1
ret = process_list(&rev1list, 0x1, 0x2);
} else if (rev1list->item->date < rev2list->item->date) {
// process 2
ret = process_list(&rev2list, 0x2, 0x1);
} else {
// process 1
ret = process_list(&rev1list, 0x1, 0x2);
}
if (ret) {
free_commit_list(rev1list);
free_commit_list(rev2list);
return ret;
}
}
return NULL;
}
int main(int argc, char **argv)
{
struct commit *rev1, *rev2, *ret;
unsigned char rev1key[20], rev2key[20];
if (argc != 3 ||
get_sha1(argv[1], rev1key) ||
get_sha1(argv[2], rev2key)) {
usage("merge-base <commit-id> <commit-id>");
}
rev1 = lookup_commit(rev1key);
rev2 = lookup_commit(rev2key);
ret = common_ancestor(rev1, rev2);
if (!ret)
return 1;
printf("%s\n", sha1_to_hex(ret->object.sha1));
return 0;
}