[rygel] ruih: Check for mandatory arguments

[Jens Georg <jensgeorg src gnome org>]

commit aa1e126b8e09a83eb48f47a048eb6ac4506d8a46
Author: Parthiban Balasubramanian <parthibanbalu1 gmail com>
Date:   Mon May 4 13:54:09 2015 -0600

    ruih: Check for mandatory arguments
    
    GetCompatibleUI action must check for 2 mandatory arguments with the action.
    Both the arguments can be empty but the element needs to be sent out in the
    request.

 src/librygel-ruih/rygel-ruih-service.vala |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/src/librygel-ruih/rygel-ruih-service.vala b/src/librygel-ruih/rygel-ruih-service.vala
index ba2cccf..acc88e7 100644
--- a/src/librygel-ruih/rygel-ruih-service.vala
+++ b/src/librygel-ruih/rygel-ruih-service.vala
@@ -59,6 +59,11 @@ internal class Rygel.RuihService: Service {
                         out input_device_profile);
         action.get ("UIFilter", typeof (string), out input_ui_filter);
 
+        if (action.get_argument_count () < 2) {
+            action.return_error (402, _("Invalid argument"));
+            return;
+        }
+
         try {
             var manager = RuihServiceManager.get_default ();
             var compat_ui = manager.get_compatible_uis (input_device_profile,