zone-api: add zone_update _add and _remove RR functions.

src/knot/updates/ddns.c

@@ -465,14 +465,14 @@ static int add_rr_to_chgset(const knot_rrset_t *rr,
 		return KNOT_EOK;
 	}
 
-	return changeset_add_rrset(&update->change, rr);
+	return zone_update_add(update, rr);
 }
 
 /*!< \brief Adds RR into remove section of changeset if it is deemed worthy. */
 static int rem_rr_to_chgset(const knot_rrset_t *rr,
                             zone_update_t *update)
 {
-	return changeset_rem_rrset(&update->change, rr);
+	return zone_update_remove(update, rr);
 }
 
 /*!< \brief Adds all RRs from RRSet into remove section of changeset. */

src/knot/updates/zone-update.c

@@ -258,6 +258,37 @@ void zone_update_clear(zone_update_t *update)
 	}
 }
 
+int zone_update_add(zone_update_t *update, const knot_rrset_t *rrset)
+{
+	if (update->flags & UPDATE_WRITING_ITER) {
+		return changeset_add_rrset(&update->iteration_changes, rrset);
+	} else if (update->flags & UPDATE_INCREMENTAL) {
+		return changeset_add_rrset(&update->change, rrset);
+	} else if (update->flags & UPDATE_FULL) {
+		zone_node_t *n = NULL;
+		return zone_contents_add_rr(update->new_cont, rrset, &n);
+	} else {
+		return KNOT_EINVAL;
+	}
+}
+
+int zone_update_remove(zone_update_t *update, const knot_rrset_t *rrset)
+{
+	if (update->flags & UPDATE_WRITING_ITER) {
+		return changeset_rem_rrset(&update->iteration_changes, rrset);
+	} else if (update->flags & UPDATE_INCREMENTAL) {
+		return changeset_rem_rrset(&update->change, rrset);
+	} else {
+		// Removing from zone during creation does not make sense, ignore.
+		/* The comment right above does not make sense when the following line
+		 * was uncommented. Anyway, right now we don't have a nice and clean way
+		 * to remove an RR. FIXME
+		 */
+		//return zone_contents_remove_rr(update->new_cont, rrset);
+		return KNOT_ENOTSUP;
+	}
+}
+
 static bool apex_rr_changed(const zone_node_t *old_apex,
                             const zone_node_t *new_apex,
                             uint16_t type)