gstreamer/sources/custom/Object.cs

//
// Authors:
//     Andrés G. Aragoneses <knocte@gmail.com>
//     Sebastian Dröge <slomo@circular-chaos.org>
//     Stephan Sundermann <stephansundermann@gmail.com>
//
// Copyright (c) 2009 Sebastian Dröge
// Copyright (c) 2013 Andrés G. Aragoneses
// Copyright (C) 2013 Stephan Sundermann
// 
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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 library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
// 02110-1301  USA

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;

namespace Gst {

	public class PropertyNotFoundException : Exception {}
	
	[StructLayout (LayoutKind.Sequential)]
    struct GstObject {
        IntPtr _lock;
        public string name;
        public Object parent;
        public uint flags;
        IntPtr controlBindings;
        public int control_rate;
        public int last_sync;

        private IntPtr[] _gstGstReserved;
    }

	partial class Object 
	{
		private Dictionary <string, bool> PropertyNameCache = new Dictionary<string, bool> ();

		[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
		static extern IntPtr g_object_class_find_property (IntPtr klass, IntPtr name);

		bool PropertyExists (string name) {
			if (PropertyNameCache.ContainsKey (name))
				return PropertyNameCache [name];

			IntPtr native_name = GLib.Marshaller.StringToPtrGStrdup (name);
			var ptr = g_object_class_find_property (Marshal.ReadIntPtr (Handle), native_name);
			var result = ptr != IntPtr.Zero;

			// just cache the positive results because there might
			// actually be new properties getting installed
			if (result)
				PropertyNameCache [name] = result;

			GLib.Marshaller.Free (native_name);
			return result;
		}

		public object this[string property] {
		  get {
				if (PropertyExists (property)) {
					using (GLib.Value v = GetProperty (property)) {
						return v.Val;
					}
				} else
					throw new PropertyNotFoundException ();
		  } set {
				if (PropertyExists (property)) {
					if (value == null) {
						throw new ArgumentNullException ();
					}
					var type = value.GetType ();
					var gtype = (GLib.GType)type;
					if (gtype == null) {
						throw new Exception ("Could not find a GType for type " + type.FullName);
					}
					GLib.Value v = new GLib.Value ((GLib.GType)value.GetType ());
					v.Val = value;
					SetProperty (property, v);
					v.Dispose ();
				} else
					throw new PropertyNotFoundException ();
		  }
		}

		public void Connect (string signal, SignalHandler handler) {
		  DynamicSignal.Connect (this, signal, handler);
		}

		public void Disconnect (string signal, SignalHandler handler) {
		  DynamicSignal.Disconnect (this, signal, handler);
		}

		public void Connect (string signal, Delegate handler) {
		  DynamicSignal.Connect (this, signal, handler);
		}

		public void Disconnect (string signal, Delegate handler) {
		  DynamicSignal.Disconnect (this, signal, handler);
		}

		public object Emit (string signal, params object[] parameters) {
		  return DynamicSignal.Emit (this, signal, parameters);
		}
	}
}