[hyena] ListView: Do not enable a11y when it would cause freezes (bgo#696111)

[Bertrand Lorentz <blorentz src gnome org>]

commit fec01af8d9602fd72a59219cd7a55da435c1be97
Author: Andres G. Aragoneses <knocte gmail com>
Date:   Tue Apr 2 12:30:09 2013 +0100

    ListView: Do not enable a11y when it would cause freezes (bgo#696111)
    
    Recent versions of glib or gobject (2.35.4 and above) don't allow
    anymore to add GInterfaces after class initialization, which causes the
    Mono binding to fail when implementing interfaces in managed land (filed
    in https://bugzilla.xamarin.com/show_bug.cgi?id=11510).
    
    We're  affected by this particularly when implementing the AtkTable
    interface for the accessibility support of the ListView custom widget.
    The consequence would be that the class would not implement the
    interface properly, which would cause lots of exceptions in
    OnCreateAccessible signals, high CPU usage and make the app hang.
    
    The workaround for now is create a dummy instance of ListViewAccessible
    class, and not enable accessibility if any exception is caught at
    creation time.
    
    Signed-off-by: Bertrand Lorentz <bertrand lorentz gmail com>

 .../Hyena.Data.Gui/ListView/ListView_Accessible.cs |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)
---
diff --git a/Hyena.Gui/Hyena.Data.Gui/ListView/ListView_Accessible.cs 
b/Hyena.Gui/Hyena.Data.Gui/ListView/ListView_Accessible.cs
index 3cdabeb..7c50e56 100644
--- a/Hyena.Gui/Hyena.Data.Gui/ListView/ListView_Accessible.cs
+++ b/Hyena.Gui/Hyena.Data.Gui/ListView/ListView_Accessible.cs
@@ -157,8 +157,17 @@ namespace Hyena.Data.Gui
     {
         public static void Init ()
         {
-            new ListViewAccessibleFactory<T> ();
-            Atk.Global.DefaultRegistry.SetFactoryType ((GLib.GType)typeof (ListView<T>), (GLib.GType)typeof 
(ListViewAccessibleFactory<T>));
+            try {
+                // Test creating a dummy accessible, which may throw if gobject binding has issues.
+                // If it throws, a11y for ListView will not be enabled.
+                // (workaround for https://bugzilla.xamarin.com/show_bug.cgi?id=11510)
+                new ListViewAccessible<T> (new ListView<T> ());
+
+                new ListViewAccessibleFactory<T> ();
+                Atk.Global.DefaultRegistry.SetFactoryType ((GLib.GType)typeof (ListView<T>), 
(GLib.GType)typeof (ListViewAccessibleFactory<T>));
+            } catch (Exception ex) {
+                Log.Exception ("Initialization of accessibility support for ListView widgets failed", ex);
+            }
         }
 
         protected override Atk.Object OnCreateAccessible (GLib.Object obj)