luci-app-ddns: get rid of luci-lib-ipkg depdency

Invoking opkg to obtain the installed package version is very slow and
resource intensive, parse the related control file directly to avoid
the extraneous dependency and resource consumption.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

applications/luci-app-ddns/Makefile

@@ -12,7 +12,7 @@ PKG_LICENSE:=Apache-2.0
 PKG_MAINTAINER:=Ansuel Smith <ansuelsmth@gmail.com>
 
 LUCI_TITLE:=LuCI Support for Dynamic DNS Client (ddns-scripts)
-LUCI_DEPENDS:=+luci-lib-ipkg +luci-mod-admin-full +ddns-scripts
+LUCI_DEPENDS:=+luci-mod-admin-full +ddns-scripts
 LUCI_PKGARCH:=all
 
 include ../../luci.mk

applications/luci-app-ddns/root/usr/libexec/rpcd/luci.ddns

@@ -153,21 +153,26 @@ local methods = {
 	},
 	get_ddns_state = {
 		call = function()
-			local ipkg = require "luci.model.ipkg"
 			local uci = UCI.cursor()
 			local dateformat = uci:get("ddns", "global", "ddns_dateformat") or "%F %R"
 			local services_mtime = fs.stat(ddns_package_path .. "/list", 'mtime')
 			uci:unload("ddns")
-			local ver, srv_ver_cmd
 			local res = {}
+			local ver
 
-			if ipkg then
-				ver = ipkg.info(srv_name)[srv_name].Version
-			else
-				srv_ver_cmd = luci_helper .. " -V | awk {'print $2'} "
-				ver = util.exec(srv_ver_cmd)
+			local _, ctrl = pcall(io.lines, "/usr/lib/opkg/info/%s.control" % srv_name)
+			if ctrl then
+				for line in ctrl do
+					ver = line:match("^Version: (.+)$")
+
+					if ver then
+						break
+					end
+				end
 			end
 
+			ver = ver or util.trim(util.exec("%s -V | awk {'print $2'}" % luci_helper))
+
 			res['_version'] = ver and #ver > 0 and ver or nil
 			res['_enabled'] = sys.init.enabled("ddns")
 			res['_curr_dateformat'] = os.date(dateformat)