mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-12-22 00:06:36 +00:00
111 lines
3.7 KiB
C#
111 lines
3.7 KiB
C#
// DelegateWrapper.cs - Delegate wrapper implementation
|
|
//
|
|
// Authors:
|
|
// Rachel Hestilow <hestilow@ximian.com>
|
|
// Gonzalo Panigua Javier <gonzalo@ximian.com>
|
|
//
|
|
// Copyright (c) 2002 Rachel Hestilow
|
|
// Copyright (c) 2003 Ximian, 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 Gst.GLib {
|
|
|
|
using System;
|
|
using System.Collections;
|
|
using System.Runtime.InteropServices;
|
|
|
|
public class DelegateWrapper
|
|
{
|
|
// Keys in the hashtable are instances of classes derived from this one.
|
|
// Values are each instance's destroy notification delegate
|
|
static Hashtable instances = new Hashtable ();
|
|
|
|
// This list holds references to wrappers for static
|
|
// methods. These will never expire.
|
|
static ArrayList static_instances = new ArrayList ();
|
|
|
|
static int notify_count = 0;
|
|
|
|
// The object 'o' is the object that creates the instance of the DelegateWrapper
|
|
// derived class or null if created from a static method.
|
|
// Note that the instances will never be disposed if they are created in a static
|
|
// method.
|
|
[Obsolete ("Callback wrappers should be manually managed for persistence.")]
|
|
protected DelegateWrapper (object o)
|
|
{
|
|
if (o != null) {
|
|
// If o is a GObject, we can get
|
|
// destroy notification. Otherwise
|
|
// no additional references to
|
|
// the wrapper are kept.
|
|
// FIXME: This should work because
|
|
// currently only GObjects store
|
|
// callbacks over the long-term
|
|
|
|
if (o is Gst.GLib.Object) {
|
|
AddDestroyNotify ((Gst.GLib.Object) o);
|
|
}
|
|
} else {
|
|
// If o is null, we cannot ask for a destroy
|
|
// notification, so the wrapper never expires.
|
|
|
|
lock (typeof (DelegateWrapper)) {
|
|
static_instances.Add (this);
|
|
}
|
|
}
|
|
}
|
|
|
|
[UnmanagedFunctionPointer (CallingConvention.Cdecl)]
|
|
private delegate void DestroyNotify (IntPtr data);
|
|
|
|
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
|
|
private static extern void g_object_set_data_full (IntPtr obj, IntPtr name, IntPtr data, DestroyNotify destroy);
|
|
|
|
private void AddDestroyNotify (Gst.GLib.Object o) {
|
|
// This is a bit of an ugly hack. There is no
|
|
// way of getting a destroy notification
|
|
// explicitly, so we set some data and ask
|
|
// for notification when it is removed
|
|
|
|
IntPtr name = Marshaller.StringToPtrGStrdup (String.Format ("_GtkSharpDelegateWrapper_{0}", notify_count));
|
|
DestroyNotify destroy = new DestroyNotify (this.OnDestroy);
|
|
|
|
g_object_set_data_full (o.Handle, name, IntPtr.Zero, destroy);
|
|
Marshaller.Free (name);
|
|
lock (typeof (DelegateWrapper)) {
|
|
instances[this] = destroy;
|
|
notify_count++;
|
|
}
|
|
}
|
|
|
|
// This callback is invoked by Gst.GLib to indicate that the
|
|
// object that owned the native delegate wrapper no longer
|
|
// exists and the instance of the delegate itself is removed from the hash table.
|
|
private void OnDestroy (IntPtr data) {
|
|
try {
|
|
lock (typeof (DelegateWrapper)) {
|
|
if (instances.ContainsKey (this)) {
|
|
instances.Remove (this);
|
|
}
|
|
}
|
|
} catch (Exception e) {
|
|
ExceptionManager.RaiseUnhandledException (e, false);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|