GtkSharp/glib/ManagedValue.cs

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// GLib.ManagedValue.cs : Managed types boxer
//
// Author: Rachel Hestilow <hestilow@ximian.com>
//
// Copyright (c) 2002 Rachel Hestilow
//
// 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;
using GLib;
// FIXME:
// This used to use GCHandles, but I rewrote it to debug
// some odd interactions. Since the boxed code in GLib is designed
// to not interact directly with the pointers, just using our own
// arbitrary pointer values is fine. Still, it might be useful
// to use GCHandle later on.
internal class ManagedValue {
private class ValueHolder {
public object val;
public int ref_count;
}
private delegate IntPtr CopyFunc (IntPtr ptr);
private delegate void FreeFunc (IntPtr ptr);
private static Hashtable pointers = new Hashtable ();
private static IntPtr cur_ptr = IntPtr.Zero;
private static CopyFunc copy;
private static FreeFunc free;
private static GType boxed_type = GType.Invalid;
[DllImport("libgobject-2.0-0.dll")]
private static extern IntPtr g_boxed_type_register_static (string typename, CopyFunc copy_func, FreeFunc free_func);
public static GType GType {
get {
if (boxed_type == GType.Invalid) {
copy = new CopyFunc (Copy);
free = new FreeFunc (Free);
boxed_type = new GLib.GType (g_boxed_type_register_static ("GtkSharpValue", copy, free));
}
return boxed_type;
}
}
public static IntPtr Copy (IntPtr ptr)
{
ValueHolder holder = (ValueHolder) pointers[ptr];
holder.ref_count++;
return ptr;
}
public static void Free (IntPtr ptr)
{
ValueHolder holder = (ValueHolder) pointers[ptr];
if (holder == null)
return;
holder.ref_count--;
if (holder.ref_count < 1)
pointers.Remove (ptr);
}
public static IntPtr WrapObject (object obj)
{
ValueHolder holder = new ValueHolder ();
holder.val = obj;
holder.ref_count = 1;
cur_ptr = new IntPtr (((int) cur_ptr) + 1);
pointers[cur_ptr] = holder;
return cur_ptr;
}
public static object ObjectForWrapper (IntPtr ptr)
{
if (!pointers.Contains (ptr))
return null;
ValueHolder holder = (ValueHolder) pointers[ptr];
return holder.val;
}
}
}