DNSSEC: use zone diff when deleting NSEC3 chain

refs #4

src/libknot/dnssec/zone-nsec.c

@@ -786,64 +786,11 @@ static int create_nsec3_chain(const knot_zone_contents_t *zone, uint32_t ttl,
 	return result;
 }
 
-/* - deleting NSEC3 chain -------------------------------------------------- */
-
-typedef struct {
-	knot_changeset_t *changeset;
-	int result;
-} nsec3_chain_delete_data_t;
-
-static int copy_node_and_delete(const knot_rrset_t *rrset,
-                                knot_changeset_t *changeset)
-{
-	knot_rrset_t *copy = NULL;
-	int result = knot_rrset_deep_copy_no_sig(rrset, &copy);
-	if (result != KNOT_EOK) {
-		return result;
-	}
-
-	result = knot_changeset_add_rrset(changeset, copy, KNOT_CHANGESET_REMOVE);
-	if (result != KNOT_EOK) {
-		knot_rrset_deep_free(&copy, 1);
-	}
-
-	return result;
-}
-
-static void delete_nsec3_chain_node_cb(knot_node_t **node_ptr, void *data)
-{
-	assert(node_ptr && *node_ptr);
-	assert(data);
-
-	knot_node_t *node = *node_ptr;
-	nsec3_chain_delete_data_t *params = (nsec3_chain_delete_data_t *)data;
-
-	if (params->result != KNOT_EOK) {
-		return;
-	}
-
-	int result = KNOT_EOK;
-
-	for (int i = 0; i < node->rrset_count; i++) {
-		const knot_rrset_t *rrset = node->rrset_tree[i];
-		result = copy_node_and_delete(rrset, params->changeset);
-		if (result != KNOT_EOK) {
-			break;
-		}
-
-		result = copy_node_and_delete(rrset->rrsigs, params->changeset);
-		if (result != KNOT_EOK) {
-			break;
-		}
-	}
-
-	params->result = result;
-}
-
 static int delete_nsec3_chain(const knot_zone_contents_t *zone,
                               knot_changeset_t *changeset)
 {
 	assert(zone);
+	assert(zone->nsec3_nodes);
 	assert(changeset);
 
 	if (knot_zone_tree_is_empty(zone->nsec3_nodes)) {
@@ -851,16 +798,17 @@ static int delete_nsec3_chain(const knot_zone_contents_t *zone,
 	}
 
 	dbg_dnssec_detail("deleting NSEC3 chain\n");
+	knot_zone_tree_t *empty_tree = knot_zone_tree_create();
+	if (!empty_tree) {
+		return KNOT_ENOMEM;
+	}
 
-	nsec3_chain_delete_data_t cb_data = {
-		.changeset = changeset,
-		.result = KNOT_EOK
-	};
+	int result = knot_zone_tree_add_diff(zone->nsec3_nodes, empty_tree,
+	                                     changeset);
 
-	knot_zone_tree_apply(zone->nsec3_nodes, delete_nsec3_chain_node_cb,
-			     &cb_data);
+	knot_zone_tree_free(&empty_tree);
 
-	return cb_data.result;
+	return result;
 }
 
 /* - helper functions ------------------------------------------------------ */