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path: root/builtin/merge-base.c
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#include "builtin.h"
#include "cache.h"
#include "commit.h"
#include "parse-options.h"
 
static int show_merge_base(struct commit **rev, int rev_nr, int show_all)
{
	struct commit_list *result;
 
	result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1, 0);
 
	if (!result)
		return 1;
 
	while (result) {
		printf("%s\n", sha1_to_hex(result->item->object.sha1));
		if (!show_all)
			return 0;
		result = result->next;
	}
 
	return 0;
}
 
static const char * const merge_base_usage[] = {
	N_("git merge-base [-a|--all] <commit> <commit>..."),
	N_("git merge-base [-a|--all] --octopus <commit>..."),
	N_("git merge-base --independent <commit>..."),
	N_("git merge-base --is-ancestor <commit> <commit>"),
	NULL
};
 
static struct commit *get_commit_reference(const char *arg)
{
	unsigned char revkey[20];
	struct commit *r;
 
	if (get_sha1(arg, revkey))
		die("Not a valid object name %s", arg);
	r = lookup_commit_reference(revkey);
	if (!r)
		die("Not a valid commit name %s", arg);
 
	return r;
}
 
static int handle_octopus(int count, const char **args, int reduce, int show_all)
{
	struct commit_list *revs = NULL;
	struct commit_list *result;
	int i;
 
	if (reduce)
		show_all = 1;
 
	for (i = count - 1; i >= 0; i--)
		commit_list_insert(get_commit_reference(args[i]), &revs);
 
	result = reduce ? reduce_heads(revs) : get_octopus_merge_bases(revs);
 
	if (!result)
		return 1;
 
	while (result) {
		printf("%s\n", sha1_to_hex(result->item->object.sha1));
		if (!show_all)
			return 0;
		result = result->next;
	}
 
	return 0;
}
 
static int handle_is_ancestor(int argc, const char **argv)
{
	struct commit *one, *two;
 
	if (argc != 2)
		die("--is-ancestor takes exactly two commits");
	one = get_commit_reference(argv[0]);
	two = get_commit_reference(argv[1]);
	if (in_merge_bases(one, two))
		return 0;
	else
		return 1;
}
 
int cmd_merge_base(int argc, const char **argv, const char *prefix)
{
	struct commit **rev;
	int rev_nr = 0;
	int show_all = 0;
	int cmdmode = 0;
 
	struct option options[] = {
		OPT_BOOL('a', "all", &show_all, N_("output all common ancestors")),
		OPT_CMDMODE(0, "octopus", &cmdmode,
			    N_("find ancestors for a single n-way merge"), 'o'),
		OPT_CMDMODE(0, "independent", &cmdmode,
			    N_("list revs not reachable from others"), 'r'),
		OPT_CMDMODE(0, "is-ancestor", &cmdmode,
			    N_("is the first one ancestor of the other?"), 'a'),
		OPT_END()
	};
 
	git_config(git_default_config, NULL);
	argc = parse_options(argc, argv, prefix, options, merge_base_usage, 0);
 
	if (cmdmode == 'a') {
		if (argc < 2)
			usage_with_options(merge_base_usage, options);
		if (show_all)
			die("--is-ancestor cannot be used with --all");
		return handle_is_ancestor(argc, argv);
	}
 
	if (cmdmode == 'r' && show_all)
		die("--independent cannot be used with --all");
 
	if (cmdmode == 'r' || cmdmode == 'o')
		return handle_octopus(argc, argv, cmdmode == 'r', show_all);
 
	if (argc < 2)
		usage_with_options(merge_base_usage, options);
 
	rev = xmalloc(argc * sizeof(*rev));
	while (argc-- > 0)
		rev[rev_nr++] = get_commit_reference(*argv++);
	return show_merge_base(rev, rev_nr, show_all);
}