convert trivial cases to FLEX_ARRAY macros

Using FLEX_ARRAY macros reduces the amount of manual
computation size we have to do. It also ensures we don't
overflow size_t, and it makes sure we write the same number
of bytes that we allocated.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/refs.c b/refs.c
index 1d9e2a7932..2d86445231 100644
--- a/refs.c
+++ b/refs.c
@@ -761,10 +761,8 @@ void ref_transaction_free(struct ref_transaction *transaction)
 static struct ref_update *add_update(struct ref_transaction *transaction,
 				     const char *refname)
 {
-	size_t len = strlen(refname) + 1;
-	struct ref_update *update = xcalloc(1, sizeof(*update) + len);
-
-	memcpy((char *)update->refname, refname, len); /* includes NUL */
+	struct ref_update *update;
+	FLEX_ALLOC_STR(update, refname, refname);
 	ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
 	transaction->updates[transaction->nr++] = update;
 	return update;