using System;
using System.Reflection;
using System.Security.Permissions;
namespace Python.Runtime
{
///
/// Implements a Python descriptor type that manages CLR properties.
///
internal class PropertyObject : ExtensionType
{
private PropertyInfo info;
private MethodInfo getter;
private MethodInfo setter;
public PropertyObject(PropertyInfo md)
{
getter = md.GetGetMethod(true);
setter = md.GetSetMethod(true);
info = md;
}
///
/// Descriptor __get__ implementation. This method returns the
/// value of the property on the given object. The returned value
/// is converted to an appropriately typed Python object.
///
public static IntPtr tp_descr_get(IntPtr ds, IntPtr ob, IntPtr tp)
{
var self = (PropertyObject)GetManagedObject(ds);
MethodInfo getter = self.getter;
object result;
if (getter == null)
{
return Exceptions.RaiseTypeError("property cannot be read");
}
if (ob == IntPtr.Zero || ob == Runtime.PyNone)
{
if (!getter.IsStatic)
{
Exceptions.SetError(Exceptions.TypeError,
"instance property must be accessed through a class instance");
return IntPtr.Zero;
}
try
{
result = self.info.GetValue(null, null);
return Converter.ToPython(result, self.info.PropertyType);
}
catch (Exception e)
{
return Exceptions.RaiseTypeError(e.Message);
}
}
var co = GetManagedObject(ob) as CLRObject;
if (co == null)
{
return Exceptions.RaiseTypeError("invalid target");
}
try
{
result = self.info.GetValue(co.inst, null);
return Converter.ToPython(result, self.info.PropertyType);
}
catch (Exception e)
{
if (e.InnerException != null)
{
e = e.InnerException;
}
Exceptions.SetError(e);
return IntPtr.Zero;
}
}
///
/// Descriptor __set__ implementation. This method sets the value of
/// a property based on the given Python value. The Python value must
/// be convertible to the type of the property.
///
public new static int tp_descr_set(IntPtr ds, IntPtr ob, IntPtr val)
{
var self = (PropertyObject)GetManagedObject(ds);
MethodInfo setter = self.setter;
object newval;
if (val == IntPtr.Zero)
{
Exceptions.RaiseTypeError("cannot delete property");
return -1;
}
if (setter == null)
{
Exceptions.RaiseTypeError("property is read-only");
return -1;
}
if (!Converter.ToManaged(val, self.info.PropertyType, out newval, true))
{
return -1;
}
bool is_static = setter.IsStatic;
if (ob == IntPtr.Zero || ob == Runtime.PyNone)
{
if (!is_static)
{
Exceptions.RaiseTypeError("instance property must be set on an instance");
return -1;
}
}
try
{
if (!is_static)
{
var co = GetManagedObject(ob) as CLRObject;
if (co == null)
{
Exceptions.RaiseTypeError("invalid target");
return -1;
}
self.info.SetValue(co.inst, newval, null);
}
else
{
self.info.SetValue(null, newval, null);
}
return 0;
}
catch (Exception e)
{
if (e.InnerException != null)
{
e = e.InnerException;
}
Exceptions.SetError(e);
return -1;
}
}
///
/// Descriptor __repr__ implementation.
///
public static IntPtr tp_repr(IntPtr ob)
{
var self = (PropertyObject)GetManagedObject(ob);
return Runtime.PyString_FromString($"");
}
}
}