reftable-backend: implement 'optimize' action

To make the new generic `optimize` API fully functional, provide an
implementation for the 'reftable' reference backend.

For the reftable backend, the 'optimize' action is to compact its
tables. The existing `reftable_be_pack_refs()` function already provides
this logic, so the new `reftable_be_optimize()` function simply calls
it.

Wire up the new function to the `optimize` slot in the reftable
backend's virtual table.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Meet Soni <meetsoni3017@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: inosmeet

refs/reftable-backend.c

@@ -1721,6 +1721,12 @@ static int reftable_be_pack_refs(struct ref_store *ref_store,
 	return ret;
 }
 
+static int reftable_be_optimize(struct ref_store *ref_store,
+				struct pack_refs_opts *opts)
+{
+	return reftable_be_pack_refs(ref_store, opts);
+}
+
 struct write_create_symref_arg {
 	struct reftable_ref_store *refs;
 	struct reftable_stack *stack;
@@ -2702,6 +2708,7 @@ struct ref_storage_be refs_be_reftable = {
 	.transaction_abort = reftable_be_transaction_abort,
 
 	.pack_refs = reftable_be_pack_refs,
+	.optimize = reftable_be_optimize,
 	.rename_ref = reftable_be_rename_ref,
 	.copy_ref = reftable_be_copy_ref,