GtkSharp/Source/glib/DestroyNotify.cs

// GLib.DestroyNotify.cs - internal DestroyNotify helper
//
// Author: Mike Kestner <mkestner@novell.com>
//
// Copyright (c) 2005 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.Runtime.InteropServices;

	[UnmanagedFunctionPointer (CallingConvention.Cdecl)]
	public delegate void DestroyNotify (IntPtr data);

	public class DestroyHelper {

		private DestroyHelper () {}
		
		static void ReleaseGCHandle (IntPtr data)
		{
			if (data == IntPtr.Zero)
				return;
			GCHandle gch = (GCHandle) data;
			gch.Free ();
		}

		static DestroyNotify release_gchandle;

		public static DestroyNotify NotifyHandler {
			get {
				if (release_gchandle == null)
					release_gchandle = new DestroyNotify (ReleaseGCHandle);
				return release_gchandle;
			}
		}
	}
}