[PATCH 2/3] builtin-remote: teach show to display remote HEAD

[Jay Soffian <jaysoffian@gmail.com>]

The remote HEAD cannot be determined unambiguosly, so use the same
heuristics as builtin-clone's locate_head().

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
---
 builtin-remote.c |   39 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/builtin-remote.c b/builtin-remote.c
index 00e7ca5..0be8bfd 100644
--- a/builtin-remote.c
+++ b/builtin-remote.c
@@ -212,6 +212,7 @@ static void read_branches(void)
 struct ref_states {
 	struct remote *remote;
 	struct string_list new, stale, tracked;
+	char *head_name;
 };
 
 static int handle_one_branch(const char *refname,
@@ -271,6 +272,38 @@ static int get_ref_states(const struct ref *ref, struct ref_states *states)
 	return 0;
 }
 
+static char *get_head_name(const struct ref *ref)
+{
+	const struct ref *remote_head = NULL;
+	const struct ref *remote_master = NULL;
+	const struct ref *r;
+	for (r = ref; r; r = r->next) {
+		if (!strcmp(r->name, "HEAD"))
+			remote_head = r;
+		if (!strcmp(r->name, "refs/heads/master"))
+			remote_master = r;
+	}
+
+	/* If there's no HEAD value at all, never mind. */
+	if (!remote_head)
+		return NULL;
+
+	/* If refs/heads/master could be right, it is. */
+	if (remote_master && !hashcmp(remote_master->old_sha1,
+				      remote_head->old_sha1))
+		return xstrdup(abbrev_branch(remote_master->name));
+
+	/* Look for another ref that points there */
+	for (r = ref; r; r = r->next)
+		if (r != remote_head &&
+		    !hashcmp(r->old_sha1, remote_head->old_sha1) &&
+		    !prefixcmp(r->name, "refs/heads/"))
+			return xstrdup(abbrev_branch(r->name));
+
+	/* Nothing is the same */
+	return NULL;
+}
+
 struct known_remote {
 	struct known_remote *next;
 	struct remote *remote;
@@ -638,6 +671,8 @@ static void free_remote_ref_states(struct ref_states *states)
 	string_list_clear(&states->new, 0);
 	string_list_clear(&states->stale, 0);
 	string_list_clear(&states->tracked, 0);
+	if (states->head_name)
+		free(states->head_name);
 }
 
 static int get_remote_ref_states(const char *name,
@@ -659,6 +694,7 @@ static int get_remote_ref_states(const char *name,
 		ref = transport_get_remote_refs(transport);
 		transport_disconnect(transport);
 
+		states->head_name = get_head_name(ref);
 		get_ref_states(ref, states);
 	}
 
@@ -703,6 +739,9 @@ static int show(int argc, const char **argv)
 		printf("* remote %s\n  URL: %s\n", *argv,
 			states.remote->url_nr > 0 ?
 				states.remote->url[0] : "(no URL)");
+		if (!no_query)
+			printf("  HEAD: %s\n", states.head_name ?
+				states.head_name : "(unknown)");
 
 		for (i = 0; i < branch_list.nr; i++) {
 			struct string_list_item *branch = branch_list.items + i;
-- 
1.6.2.rc0.187.g9fcfb