add TCP and UDP server samples

samples/tcpsrv.lua

@@ -0,0 +1,52 @@
+#! /usr/bin/env lua
+
+--
+-- Sample TCP echo server. Listens on 3333 port
+-- Use netcat to send strings to server (ncat 127.0.0.1 3333)
+--
+
+local lgi = require 'lgi'
+local Gio = lgi.Gio
+
+local app = Gio.Application { application_id = 'org.test.tcptest', flags = 'NON_UNIQUE' }
+
+local service = Gio.SocketService.new()
+service:add_address(
+   Gio.InetSocketAddress.new_from_string("127.0.0.1", 3333),
+   "STREAM", "TCP")
+
+local function get_message(conn, istream, ostream)
+   ostream:async_write("> ")
+   local bytes = istream:async_read_bytes(4096)
+   while bytes:get_size() > 0 do
+      print(string.format("Data: %s",
+			  bytes.data:sub(1, bytes:get_size()-1)))
+      ostream:async_write(bytes.data)
+      ostream:async_write("> ")
+      bytes = istream:async_read_bytes(4096)
+   end
+   print("Closing connection")
+   conn:close()
+end
+
+function service:on_incoming(conn)
+   local istream = conn:get_input_stream()
+   local ostream = conn:get_output_stream()
+   local rc = conn:get_remote_address()
+   print(string.format("Incoming connection from %s:%s",
+		       rc:get_address():to_string(),
+		       rc:get_port()))
+   Gio.Async.call(function(ostream)
+	 ostream:async_write("Connected\n")
+   end)(ostream)
+   Gio.Async.start(get_message)(conn, istream, ostream)
+   return false
+end
+
+service:start()
+
+function app:on_activate()
+   app:hold()
+end
+
+app:run({arg[0]})

samples/udpsrv.lua

@@ -0,0 +1,39 @@
+#! /usr/bin/env lua
+
+--
+-- Sample UDP server. Listens on 3333 port
+-- Use netcat to send strings to server (ncat -u 127.0.0.1 3333)
+--
+
+local lgi = require 'lgi'
+local Gio = lgi.Gio
+
+local app = Gio.Application { application_id = 'org.v1993.udptest', flags = 'NON_UNIQUE' }
+
+local socket = lgi.Gio.Socket.new('IPV4', 'DATAGRAM', 'UDP')
+local sa = lgi.Gio.InetSocketAddress.new(Gio.InetAddress.new_loopback('IPV4'), 3333)
+assert(socket:bind(sa, true))
+
+do
+   -- To avoid extra allocations
+   local buf = require("lgi.core").bytes.new(4096)
+   local source = socket:create_source('IN')
+   source:set_callback(function()
+	 print('Data incoming')
+	 local len, src = socket:receive_from(buf)
+	 if len > 0 then
+	    print(('%s:%d %s'):format(src:get_address():to_string(), src:get_port(), tostring(buf):sub(1, len)))
+	 else
+	    print('Failed to read data')
+	 end
+	 return true
+   end)
+
+   source:attach(lgi.GLib.MainContext.default())
+end
+
+function app:on_activate()
+   app:hold()
+end
+
+app:run({arg[0]})