Ground work for reincorporating software updater for select platforms.

service/OneService.hpp

@@ -34,6 +34,15 @@ namespace ZeroTier {
 
 /**
  * Local service for ZeroTier One as system VPN/NFV provider
+ *
+ * If built with ZT_ENABLE_NETWORK_CONTROLLER defined, this includes and
+ * runs controller/SqliteNetworkController with a database called
+ * controller.db in the specified home directory.
+ *
+ * If built with ZT_AUTO_UPDATE, an official ZeroTier update URL is
+ * periodically checked and updates are automatically downloaded, verified
+ * against a built-in list of update signing keys, and installed. This is
+ * only supported for certain platforms.
  */
 class OneService
 {
@@ -69,6 +78,11 @@ public:
 	 */
 	static std::string platformDefaultHomePath();
 
+	/**
+	 * @return Auto-update URL or empty string if auto-updates unsupported or not enabled
+	 */
+	static std::string autoUpdateUrl();
+
 	/**
 	 * Create a new instance of the service
 	 *