openwrt: save cache to disk when reboot system

package/luci/files/luci/i18n/smartdns.zh-cn.po

@@ -37,6 +37,9 @@ msgstr "屏蔽域名"
 msgid "Block domain."
 msgstr "屏蔽域名。"
 
+msgid "Cache Persist"
+msgstr "持久化缓存"
+
 msgid "Cache Size"
 msgstr "缓存大小"
 
@@ -537,6 +540,9 @@ msgstr ""
 "用于校验 TLS 服务器的有效性，数值为 Base64 编码的 SPKI 指纹，留空表示不验证 "
 "TLS 的合法性。"
 
+msgid "Write cache to disk on exit and load on startup."
+msgstr "退出时保存cache到磁盘，启动时加载。"
+
 msgid "domain list (/etc/smartdns/domain-set)"
 msgstr "域名列表（/etc/smartdns/domain-set）"
 

package/luci/files/root/www/luci-static/resources/view/smartdns/smartdns.js

@@ -242,6 +242,11 @@ return view.extend({
 		o = s.taboption("advanced", form.Value, "cache_size", _("Cache Size"), _("DNS domain result cache size"));
 		o.rempty = true;
 
+		// cache-persist;
+		o = s.taboption("advanced", form.Flag, "cache_persist", _("Cache Persist"), _("Write cache to disk on exit and load on startup."));
+		o.rmempty = false;
+		o.default = o.enabled;
+
 		// cache-size;
 		o = s.taboption("advanced", form.Flag, "resolve_local_hostnames", _("Resolve Local Hostnames"), _("Resolve local hostnames by reading Dnsmasq lease file."));
 		o.rmempty = false;