[rygel] renderer: Return 701 for play action in bad state

[Jens Georg <jensgeorg src gnome org>]

commit 3c2349c82fdd557fdf2ac4d538b79577478b042f
Author: Simon Mikuda <simon mikuda streamunlimited com>
Date:   Thu Feb 26 15:49:20 2015 +0100

    renderer: Return 701 for play action in bad state
    
    Only accept play actions in state STOPPED or PAUSED
    
    Signed-off-by: Simon Mikuda <simon mikuda streamunlimited com>

 src/librygel-renderer/rygel-av-transport.vala |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/src/librygel-renderer/rygel-av-transport.vala b/src/librygel-renderer/rygel-av-transport.vala
index 4479df9..dbe7682 100644
--- a/src/librygel-renderer/rygel-av-transport.vala
+++ b/src/librygel-renderer/rygel-av-transport.vala
@@ -468,6 +468,13 @@ internal class Rygel.AVTransport : Service {
             return;
         }
 
+        if (this.controller.playback_state != "STOPPED"
+            && this.controller.playback_state != "PAUSED_PLAYBACK") {
+            action.return_error (701, _("Transition not available"));
+
+            return;
+        }
+
         // Speed change will take effect when playback state is changed
         this.player.playback_speed = speed;
         this.controller.playback_state = "PLAYING";