[rygel] core: Check availability of DBus interface

[Jens Georg <jensgeorg src gnome org>]

commit 87ec0afffc96cc4d10d5407a896d28deebd26f00
Author: Jens Georg <mail jensge org>
Date:   Thu Sep 22 18:51:48 2011 +0200

    core: Check availability of DBus interface
    
    Only show debug message if thumbnail DBus service is not available
    and also not activatable.

 src/rygel/rygel-dbus-thumbnailer.vala |   35 ++++++++++++++++++++++++++++----
 src/rygel/rygel-thumbnailer.vala      |    8 ++++--
 2 files changed, 35 insertions(+), 8 deletions(-)
---
diff --git a/src/rygel/rygel-dbus-thumbnailer.vala b/src/rygel/rygel-dbus-thumbnailer.vala
index 3a48316..ec289d3 100644
--- a/src/rygel/rygel-dbus-thumbnailer.vala
+++ b/src/rygel/rygel-dbus-thumbnailer.vala
@@ -39,6 +39,8 @@ internal class Rygel.DbusThumbnailer : GLib.Object {
     private bool is_running  = false;
     private string file_path;
 
+    public bool available { get; private set; }
+
     const string THUMBNAILER_IFACE = "org.freedesktop.thumbnails.Thumbnailer1";
     const string THUMBNAILER_SERVICE =
                                     "/org/freedesktop/thumbnails/Thumbnailer1";
@@ -51,12 +53,35 @@ internal class Rygel.DbusThumbnailer : GLib.Object {
 
 
     public DbusThumbnailer () throws GLib.IOError {
-        this.tumbler = GLib.Bus.get_proxy_sync (BusType.SESSION,
-                                                THUMBNAILER_IFACE,
-                                                THUMBNAILER_SERVICE);
+        this.available = false;
+        Bus.watch_name (BusType.SESSION,
+                        THUMBNAILER_IFACE,
+                        BusNameWatcherFlags.AUTO_START,
+                        this.on_name_available,
+                        this.on_name_unavailable);
+
+    }
+
+    public void on_name_available (DBusConnection connection,
+                                   string         name,
+                                   string         owner) {
+        try {
+            this.tumbler = connection.get_proxy_sync (THUMBNAILER_IFACE,
+                                                      THUMBNAILER_SERVICE);
+
+            tumbler.Finished.connect (on_finished);
+            tumbler.Error.connect (on_error);
+            this.available = true;
+            debug ("DBus thumbnailer service available");
+        } catch (Error error) {
+            this.available = false;
+        }
+    }
 
-        tumbler.Finished.connect (on_finished);
-        tumbler.Error.connect (on_error);
+    public void on_name_unavailable (DBusConnection connection,
+                                     string         name) {
+        this.available = false;
+        debug ("DBus thumbnailer service not available");
     }
 
     public async void create_thumbnail_task (string file_path,
diff --git a/src/rygel/rygel-thumbnailer.vala b/src/rygel/rygel-thumbnailer.vala
index 3f3fb5d..40d1e56 100644
--- a/src/rygel/rygel-thumbnailer.vala
+++ b/src/rygel/rygel-thumbnailer.vala
@@ -77,8 +77,8 @@ internal class Rygel.Thumbnailer : GLib.Object {
 
         try {
             this.thumbler = new DbusThumbnailer ();
-       } catch (GLib.IOError error) {}
-
+       } catch (GLib.Error error) {
+       }
     }
 
     public static Thumbnailer? get_default () {
@@ -104,7 +104,9 @@ internal class Rygel.Thumbnailer : GLib.Object {
         var file = File.new_for_path (full_path);
 
         // send a request to create thumbnail if it does not exist
-        if ((this.thumbler != null) && (!file.query_exists ())) {
+        if (this.thumbler != null &&
+            this.thumbler.available &&
+            !file.query_exists ()) {
             this.thumbler.create_thumbnail_task (uri, mime_type, "normal");
         }