[rygel] external: Simplify and fix translatable message

[Jens Georg <jensgeorg src gnome org>]

commit be20dc1cc8bb7bf455b38117d8a6ebfab5ab4d25
Author: Jens Georg <jensg openismus com>
Date:   Thu Aug 15 12:26:24 2013 +0200

    external: Simplify and fix translatable message
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705899

 .../rygel-dlna-profile.vala                        |    1 -
 .../external/rygel-external-variant-util.vala      |   33 ++++++++++++-------
 2 files changed, 21 insertions(+), 13 deletions(-)
---
diff --git a/src/librygel-server/rygel-dlna-profile.vala b/src/librygel-core/rygel-dlna-profile.vala
similarity index 99%
rename from src/librygel-server/rygel-dlna-profile.vala
rename to src/librygel-core/rygel-dlna-profile.vala
index 5abb22e..20ec1c8 100644
--- a/src/librygel-server/rygel-dlna-profile.vala
+++ b/src/librygel-core/rygel-dlna-profile.vala
@@ -42,4 +42,3 @@ public class Rygel.DLNAProfile {
         return a.name.ascii_casecmp (b.name);
     }
 }
-
diff --git a/src/plugins/external/rygel-external-variant-util.vala 
b/src/plugins/external/rygel-external-variant-util.vala
index 1f564c1..3ef3d1c 100644
--- a/src/plugins/external/rygel-external-variant-util.vala
+++ b/src/plugins/external/rygel-external-variant-util.vala
@@ -19,18 +19,31 @@
  */
 
 namespace Rygel.External {
-    public static string get_mandatory_string_value
+    public static string MANDATORY_MISSING_MESSAGE =
+        N_("External provider %s did not provide mandatory property \"%s\"");
+
+    public static Variant? get_mandatory
                                     (HashTable<string, Variant> props,
                                      string                     key,
-                                     string                     default,
                                      string                     service_name) {
         var value = props.lookup (key);
         if (value == null) {
-            warning (_("External provider %s did not provide mandatory " +
-                       "property \"%s\""),
-                     service_name,
-                     key);
+            warning (_(MANDATORY_MISSING_MESSAGE), service_name, key);
+
+            return null;
+        }
 
+        return value;
+    }
+
+    public static string get_mandatory_string_value
+                                    (HashTable<string, Variant> props,
+                                     string                     key,
+                                     string                     default,
+                                     string                     service_name) {
+        var value = get_mandatory (props, key, service_name);
+
+        if (value == null) {
             return default;
         }
 
@@ -42,13 +55,9 @@ namespace Rygel.External {
                                      string                     key,
                                      string[]?                  default,
                                      string                     service_name) {
-        var value = props.lookup (key);
-        if (value == null) {
-            warning (_("External provider %s did not provide mandatory " +
-                       "property \"%s\""),
-                     service_name,
-                     key);
+        var value = get_mandatory (props, key, service_name);
 
+        if (value == null) {
             return default;
         }