1 files changed, 159 insertions, 0 deletions
diff --git a/gstreamer-sharp/glib-sharp/ToggleRef.cs b/gstreamer-sharp/glib-sharp/ToggleRef.cs
new file mode 100644
index 0000000..1a16c86
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+++ b/gstreamer-sharp/glib-sharp/ToggleRef.cs
@@ -0,0 +1,159 @@
+// GLib.ToggleRef.cs - GLib ToggleRef class implementation
+//
+// Author: Mike Kestner <mkestner@novell.com>
+//
+// Copyright <c> 2007 Novell, Inc.
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of version 2 of the Lesser GNU General 
+// Public License as published by the Free Software Foundation.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this program; if not, write to the
+// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+// Boston, MA 02111-1307, USA.
+
+
+namespace GLib {
+
+	using System;
+	using System.Collections;
+	using System.Runtime.InteropServices;
+
+	internal class ToggleRef {
+
+		bool hardened;
+		IntPtr handle;
+		object reference;
+		GCHandle gch;
+		Hashtable signals;
+
+		public ToggleRef (GLib.Object target)
+		{
+			handle = target.Handle;
+			gch = GCHandle.Alloc (this);
+			reference = target;
+			g_object_add_toggle_ref (target.Handle, ToggleNotifyCallback, (IntPtr) gch);
+			g_object_unref (target.Handle);
+		}
+
+		public bool IsAlive {
+			get {
+				if (reference is WeakReference) {
+					WeakReference weak = reference as WeakReference;
+					return weak.IsAlive;
+				} else if (reference == null)
+					return false;
+				return true;
+			}
+		}
+
+		public IntPtr Handle {
+			get {
+				return handle;
+			}
+		}
+
+		public Hashtable Signals {
+			get {
+				if (signals == null)
+					signals = new Hashtable ();
+				return signals;
+			}
+		}
+
+		public GLib.Object Target {
+			get {
+				if (reference == null)
+					return null;
+				else if (reference is GLib.Object)
+					return reference as GLib.Object;
+
+				WeakReference weak = reference as WeakReference;
+				return weak.Target as GLib.Object;
+			}
+		}
+
+  		public void Free ()
+  		{
+			Signal[] signals = new Signal [Signals.Count];
+			Signals.Values.CopyTo (signals, 0);
+			foreach (Signal s in signals)
+				s.Free ();
+			if (hardened)
+				g_object_unref (handle);
+			else
+				g_object_remove_toggle_ref (handle, ToggleNotifyCallback, (IntPtr) gch);
+			reference = null;
+			gch.Free ();
+		}
+
+		internal void Harden ()
+		{
+			// Added for the benefit of GnomeProgram.  It releases a final ref in
+			// an atexit handler which causes toggle ref notifications to occur after 
+			// our delegates are gone, so we need a mechanism to override the 
+			// notifications.  This method effectively leaks all objects which invoke it, 
+			// but since it is only used by Gnome.Program, which is a singleton object 
+			// with program duration persistence, who cares.
+
+			g_object_ref (handle);
+			g_object_remove_toggle_ref (handle, ToggleNotifyCallback, (IntPtr) gch);
+			if (reference is WeakReference)
+				reference = (reference as WeakReference).Target;
+			hardened = true;
+		}
+
+		void Toggle (bool is_last_ref)
+		{
+			if (is_last_ref && reference is GLib.Object)
+				reference = new WeakReference (reference);
+			else if (!is_last_ref && reference is WeakReference) {
+				WeakReference weak = reference as WeakReference;
+				if (weak.IsAlive)
+					reference = weak.Target;
+			}
+		}
+
+		[UnmanagedFunctionPointer (CallingConvention.Cdecl)]
+		delegate void ToggleNotifyHandler (IntPtr data, IntPtr handle, bool is_last_ref);
+
+		static void RefToggled (IntPtr data, IntPtr handle, bool is_last_ref)
+		{
+			try {
+				GCHandle gch = (GCHandle) data;
+				ToggleRef tref = gch.Target as ToggleRef;
+				tref.Toggle (is_last_ref);
+			} catch (Exception e) {
+				ExceptionManager.RaiseUnhandledException (e, false);
+			}
+		}
+
+		static ToggleNotifyHandler toggle_notify_callback;
+		static ToggleNotifyHandler ToggleNotifyCallback {
+			get {
+				if (toggle_notify_callback == null)
+					toggle_notify_callback = new ToggleNotifyHandler (RefToggled);
+				return toggle_notify_callback;
+			}
+		}
+
+		[DllImport("libgobject-2.0-0.dll")]
+		static extern void g_object_add_toggle_ref (IntPtr raw, ToggleNotifyHandler notify_cb, IntPtr data);
+
+		[DllImport("libgobject-2.0-0.dll")]
+		static extern void g_object_remove_toggle_ref (IntPtr raw, ToggleNotifyHandler notify_cb, IntPtr data);
+
+		[DllImport("libgobject-2.0-0.dll")]
+		static extern IntPtr g_object_ref (IntPtr raw);
+
+		[DllImport("libgobject-2.0-0.dll")]
+		static extern void g_object_unref (IntPtr raw);
+
+	}
+}