cache API: add a "INDEX_STATE_INIT" macro/function, add release_index()

Hopefully in some not so distant future, we'll get advantages from always
initializing the "repo" member of the "struct index_state". To make
that easier let's introduce an initialization macro & function.

The various ad-hoc initialization of the structure can then be changed
over to it, and we can remove the various "0" assignments in
discard_index() in favor of calling index_state_init() at the end.

While not strictly necessary, let's also change the CALLOC_ARRAY() of
various "struct index_state *" to use an ALLOC_ARRAY() followed by
index_state_init() instead.

We're then adding the release_index() function and converting some
callers (including some of these allocations) over to it if they
either won't need to use their "struct index_state" again, or are just
about to call index_state_init().

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/builtin/difftool.c b/builtin/difftool.c
index 1f9d432..758e7bd 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -361,7 +361,7 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 	struct hashmap symlinks2 = HASHMAP_INIT(pair_cmp, NULL);
 	struct hashmap_iter iter;
 	struct pair_entry *entry;
-	struct index_state wtindex = { 0 };
+	struct index_state wtindex = INDEX_STATE_INIT;
 	struct checkout lstate, rstate;
 	int err = 0;
 	struct child_process cmd = CHILD_PROCESS_INIT;