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#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_list *parent, *temp;
struct commit_list *posn = *list_p;
*list_p = NULL;
while (posn) {
parse_commit(posn->item);
if (posn->item->object.flags & this_mark) {
/*
printf("%d already seen %s %x\n",
this_mark
sha1_to_hex(posn->parent->sha1),
posn->parent->flags);
*/
/* do nothing; this indicates that this side
* split and reformed, and we only need to
* mark it once.
*/
} else if (posn->item->object.flags & other_mark) {
return posn->item;
} else {
/*
printf("%d based on %s\n",
this_mark,
sha1_to_hex(posn->parent->sha1));
*/
posn->item->object.flags |= this_mark;
parent = posn->item->parents;
while (parent) {
temp = malloc(sizeof(struct commit_list));
temp->next = *list_p;
temp->item = parent->item;
*list_p = temp;
parent = parent->next;
}
}
posn = posn->next;
}
return NULL;
}
struct commit *common_ancestor(struct commit *rev1, struct commit *rev2)
{
struct commit_list *rev1list = malloc(sizeof(struct commit_list));
struct commit_list *rev2list = malloc(sizeof(struct commit_list));
rev1list->item = rev1;
rev1list->next = NULL;
rev2list->item = rev2;
rev2list->next = NULL;
while (rev1list || rev2list) {
struct commit *ret;
ret = process_list(&rev1list, 0x1, 0x2);
if (ret) {
/* XXXX free lists */
return ret;
}
ret = process_list(&rev2list, 0x2, 0x1);
if (ret) {
/* XXXX free lists */
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_hex(argv[1], rev1key) ||
get_sha1_hex(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;
}
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