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// Gst.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 Gst.GLib {
using System;
using System.Collections;
using System.Runtime.InteropServices;
using GLib;
internal class ManagedValue {
GCHandle gch;
object instance;
int ref_count = 1;
private ManagedValue (object instance)
{
this.instance = instance;
gch = GCHandle.Alloc (this);
}
IntPtr Handle {
get { return (IntPtr) gch; }
}
object Instance {
get { return instance; }
}
void Ref ()
{
ref_count++;
}
void Unref ()
{
if (--ref_count == 0) {
instance = null;
gch.Free ();
}
}
[UnmanagedFunctionPointer (CallingConvention.Cdecl)]
delegate IntPtr CopyFunc (IntPtr gch);
[UnmanagedFunctionPointer (CallingConvention.Cdecl)]
delegate void FreeFunc (IntPtr gch);
static CopyFunc copy;
static FreeFunc free;
static GType boxed_type = GType.Invalid;
[DllImport("libgobject-2.0-0.dll")]
static extern IntPtr g_boxed_type_register_static (IntPtr 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);
IntPtr name = Marshaller.StringToPtrGStrdup ("GstGLibSharpValue");
boxed_type = new Gst.GLib.GType (g_boxed_type_register_static (name, copy, free));
Marshaller.Free (name);
}
return boxed_type;
}
}
static ManagedValue FromHandle (IntPtr ptr)
{
GCHandle gch = (GCHandle) ptr;
ManagedValue val = gch.Target as ManagedValue;
if (val == null)
throw new Exception ("Unexpected GCHandle received.");
return val;
}
static IntPtr Copy (IntPtr ptr)
{
try {
if (ptr == IntPtr.Zero)
return ptr;
ManagedValue val = FromHandle (ptr);
val.Ref ();
return ptr;
} catch (Exception e) {
ExceptionManager.RaiseUnhandledException (e, false);
}
return IntPtr.Zero;
}
static void Free (IntPtr ptr)
{
try {
if (ptr == IntPtr.Zero)
return;
ManagedValue val = FromHandle (ptr);
val.Unref ();
} catch (Exception e) {
ExceptionManager.RaiseUnhandledException (e, false);
}
}
public static IntPtr WrapObject (object obj)
{
if (obj == null)
return IntPtr.Zero;
return new ManagedValue (obj).Handle;
}
public static object ObjectForWrapper (IntPtr ptr)
{
if (ptr == IntPtr.Zero)
return null;
ManagedValue val = FromHandle (ptr);
return val == null ? null : val.Instance;
}
public static void ReleaseWrapper (IntPtr ptr)
{
if (ptr == IntPtr.Zero)
return;
ManagedValue val = FromHandle (ptr);
val.Unref ();
}
}
}
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