improve physical structure

Network/NetworkServerLookup.hpp

@@ -0,0 +1,38 @@
+#ifndef NETWORK_SERVER_LOOKUP_HPP__
+#define NETWORK_SERVER_LOOKUP_HPP__
+
+#include <tuple>
+
+#include <QHostAddress>
+#include <QAbstractSocket>
+
+class QString;
+
+//
+// Do a blocking DNS lookup using query as a destination host address
+// and port.
+//
+// query can be one of:
+//
+// 1) "" (empty string) - use defaults
+// 2) ":nnnnn" - override default service port with port nnnnn
+// 3) "<valid-host-name>" - override default host address with DNS lookup
+// 4) "nnn.nnn.nnn.nnn" - override default host address with the IPv4 address given by nnn.nnn.nnn.nnn
+// 5) "[<valid-IPv6-address]" - override default host address with the given IPv6 address
+// 6) "<valid-host-name>:nnnnn" - use as per (3) & (2)
+// 7) "nnn.nnn.nnn.nnn:nnnnn" - use as per (4) & (2)
+// 8) "[<valid-IPv6-address]:nnnnn" - use as per (5) & (2)
+//
+// The first host address matching the protocol and the service port
+// number are returned.
+//
+// If no suitable host address is found QHostAddress::Null will be
+// returned in the first member of the result tuple.
+//
+std::tuple<QHostAddress, quint16>
+network_server_lookup (QString query
+		       , quint16 default_service_port
+		       , QHostAddress default_host_address = QHostAddress::LocalHost
+		       , QAbstractSocket::NetworkLayerProtocol protocol = QAbstractSocket::AnyIPProtocol);
+
+#endif