refs: implement releasing ref storages

Ref storages are typically only initialized once for `the_repository`
and then never released. Until now we got away with that without causing
memory leaks because `the_repository` stays reachable, and because the
ref backend is reachable via `the_repository` its memory basically never
leaks.

This is about to change though because of the upcoming migration logic,
which will create a secondary ref storage. In that case, we will either
have to release the old or new ref storage to avoid leaks.

Implement a new `release` callback and expose it via a new
`ref_storage_release()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/refs.c b/refs.c
index ebc6de81e9..0f4d327c47 100644
--- a/refs.c
+++ b/refs.c
@@ -2041,6 +2041,12 @@ static struct ref_store *ref_store_init(struct repository *repo,
 	return refs;
 }
 
+void ref_store_release(struct ref_store *ref_store)
+{
+	ref_store->be->release(ref_store);
+	free(ref_store->gitdir);
+}
+
 struct ref_store *get_main_ref_store(struct repository *r)
 {
 	if (r->refs_private)