using System;
using System.Collections;
using System.Reflection;
using System.Security.Permissions;
namespace Python.Runtime
{
//========================================================================
// Implements a Python descriptor type that manages CLR properties.
//========================================================================
internal class PropertyObject : ExtensionType
{
PropertyInfo info;
MethodInfo getter;
MethodInfo setter;
[StrongNameIdentityPermissionAttribute(SecurityAction.Assert)]
public PropertyObject(PropertyInfo md) : base()
{
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)
{
PropertyObject 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);
}
}
CLRObject 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 static new int tp_descr_set(IntPtr ds, IntPtr ob, IntPtr val)
{
PropertyObject 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)
{
CLRObject 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)
{
PropertyObject self = (PropertyObject)GetManagedObject(ob);
string s = String.Format("", self.info.Name);
return Runtime.PyString_FromStringAndSize(s, s.Length);
}
}
}