// ==========================================================================
// This software is subject to the provisions of the Zope Public License,
// Version 2.0 (ZPL). A copy of the ZPL should accompany this distribution.
// THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
// WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
// FOR A PARTICULAR PURPOSE.
// ==========================================================================
using System;
using System.Runtime.InteropServices;
using System.Collections;
using System.Reflection;
namespace Python.Runtime {
//========================================================================
// The managed metatype. This object implements the type of all reflected
// types. It also provides support for single-inheritance from reflected
// managed types.
//========================================================================
internal class MetaType : ManagedType {
static IntPtr PyCLRMetaType;
//====================================================================
// Metatype initialization. This bootstraps the CLR metatype to life.
//====================================================================
public static IntPtr Initialize() {
PyCLRMetaType = TypeManager.CreateMetaType(typeof(MetaType));
return PyCLRMetaType;
}
//====================================================================
// Metatype __new__ implementation. This is called to create a new
// class / type when a reflected class is subclassed.
//====================================================================
public static IntPtr tp_new(IntPtr tp, IntPtr args, IntPtr kw) {
int len = Runtime.PyTuple_Size(args);
if (len < 3) {
return Exceptions.RaiseTypeError("invalid argument list");
}
//IntPtr name = Runtime.PyTuple_GetItem(args, 0);
IntPtr bases = Runtime.PyTuple_GetItem(args, 1);
IntPtr dict = Runtime.PyTuple_GetItem(args, 2);
// We do not support multiple inheritance, so the bases argument
// should be a 1-item tuple containing the type we are subtyping.
// That type must itself have a managed implementation. We check
// that by making sure its metatype is the CLR metatype.
if (Runtime.PyTuple_Size(bases) != 1) {
return Exceptions.RaiseTypeError(
"cannot use multiple inheritance with managed classes"
);
}
IntPtr base_type = Runtime.PyTuple_GetItem(bases, 0);
IntPtr mt = Runtime.PyObject_TYPE(base_type);
if (!((mt == PyCLRMetaType) || (mt == Runtime.PyTypeType))) {
return Exceptions.RaiseTypeError("invalid metatype");
}
// Ensure that the reflected type is appropriate for subclassing,
// disallowing subclassing of delegates, enums and array types.
ClassBase cb = GetManagedObject(base_type) as ClassBase;
if (cb != null) {
if (! cb.CanSubclass() ) {
return Exceptions.RaiseTypeError(
"delegates, enums and array types cannot be subclassed"
);
}
}
IntPtr slots = Runtime.PyDict_GetItemString(dict, "__slots__");
if (slots != IntPtr.Zero) {
return Exceptions.RaiseTypeError(
"subclasses of managed classes do not support __slots__"
);
}
// hack for now... fix for 1.0
//return TypeManager.CreateSubType(args);
// right way
IntPtr func = Marshal.ReadIntPtr(Runtime.PyTypeType,
TypeOffset.tp_new);
IntPtr type = NativeCall.Call_3(func, tp, args, kw);
if (type == IntPtr.Zero) {
return IntPtr.Zero;
}
int flags = TypeFlags.Default;
flags |= TypeFlags.Managed;
flags |= TypeFlags.HeapType;
flags |= TypeFlags.BaseType;
flags |= TypeFlags.Subclass;
flags |= TypeFlags.HaveGC;
Marshal.WriteIntPtr(type, TypeOffset.tp_flags, (IntPtr)flags);
TypeManager.CopySlot(base_type, type, TypeOffset.tp_dealloc);
// Hmm - the standard subtype_traverse, clear look at ob_size to
// do things, so to allow gc to work correctly we need to move
// our hidden handle out of ob_size. Then, in theory we can
// comment this out and still not crash.
TypeManager.CopySlot(base_type, type, TypeOffset.tp_traverse);
TypeManager.CopySlot(base_type, type, TypeOffset.tp_clear);
// for now, move up hidden handle...
IntPtr gc = Marshal.ReadIntPtr(base_type, TypeOffset.magic());
Marshal.WriteIntPtr(type, TypeOffset.magic(), gc);
//DebugUtil.DumpType(base_type);
//DebugUtil.DumpType(type);
return type;
}
public static IntPtr tp_alloc(IntPtr mt, int n) {
IntPtr type = Runtime.PyType_GenericAlloc(mt, n);
return type;
}
public static void tp_free(IntPtr tp) {
Runtime.PyObject_GC_Del(tp);
}
//====================================================================
// Metatype __call__ implementation. This is needed to ensure correct
// initialization (__init__ support), because the tp_call we inherit
// from PyType_Type won't call __init__ for metatypes it doesnt know.
//====================================================================
public static IntPtr tp_call(IntPtr tp, IntPtr args, IntPtr kw) {
IntPtr func = Marshal.ReadIntPtr(tp, TypeOffset.tp_new);
if (func == IntPtr.Zero) {
return Exceptions.RaiseTypeError("invalid object");
}
IntPtr obj = NativeCall.Call_3(func, tp, args, kw);
if (obj == IntPtr.Zero) {
return IntPtr.Zero;
}
IntPtr py__init__ = Runtime.PyString_FromString("__init__");
IntPtr type = Runtime.PyObject_TYPE(obj);
IntPtr init = Runtime._PyType_Lookup(type, py__init__);
Runtime.Decref(py__init__);
Runtime.PyErr_Clear();
if (init != IntPtr.Zero) {
IntPtr bound = Runtime.GetBoundArgTuple(obj, args);
if (bound == IntPtr.Zero) {
Runtime.Decref(obj);
return IntPtr.Zero;
}
IntPtr result = Runtime.PyObject_Call(init, bound, kw);
Runtime.Decref(bound);
if (result == IntPtr.Zero) {
Runtime.Decref(obj);
return IntPtr.Zero;
}
Runtime.Decref(result);
}
return obj;
}
//====================================================================
// Type __setattr__ implementation for reflected types. Note that this
// is slightly different than the standard setattr implementation for
// the normal Python metatype (PyTypeType). We need to look first in
// the type object of a reflected type for a descriptor in order to
// support the right setattr behavior for static fields and properties.
//====================================================================
public static int tp_setattro(IntPtr tp, IntPtr name, IntPtr value) {
IntPtr descr = Runtime._PyType_Lookup(tp, name);
if (descr != IntPtr.Zero) {
IntPtr dt = Runtime.PyObject_TYPE(descr);
IntPtr fp = Marshal.ReadIntPtr(dt, TypeOffset.tp_descr_set);
if (fp != IntPtr.Zero) {
return NativeCall.Impl.Int_Call_3(fp, descr, name, value);
}
Exceptions.SetError(Exceptions.AttributeError,
"attribute is read-only");
return -1;
}
if (Runtime.PyObject_GenericSetAttr(tp, name, value) < 0) {
return -1;
}
return 0;
}
//====================================================================
// The metatype has to implement [] semantics for generic types, so
// here we just delegate to the generic type def implementation. Its
// own mp_subscript
//====================================================================
public static IntPtr mp_subscript(IntPtr tp, IntPtr idx) {
ClassBase cb = GetManagedObject(tp) as ClassBase;
if (cb != null) {
return cb.type_subscript(idx);
}
return Exceptions.RaiseTypeError("unsubscriptable object");
}
//====================================================================
// Dealloc implementation. This is called when a Python type generated
// by this metatype is no longer referenced from the Python runtime.
//====================================================================
public static void tp_dealloc(IntPtr tp) {
// Fix this when we dont cheat on the handle for subclasses!
int flags = (int)Marshal.ReadIntPtr(tp, TypeOffset.tp_flags);
if ((flags & TypeFlags.Subclass) == 0) {
IntPtr gc = Marshal.ReadIntPtr(tp, TypeOffset.magic());
((GCHandle)gc).Free();
}
IntPtr op = Marshal.ReadIntPtr(tp, TypeOffset.ob_type);
Runtime.Decref(op);
// Delegate the rest of finalization the Python metatype. Note
// that the PyType_Type implementation of tp_dealloc will call
// tp_free on the type of the type being deallocated - in this
// case our CLR metatype. That is why we implement tp_free.
op = Marshal.ReadIntPtr(Runtime.PyTypeType, TypeOffset.tp_dealloc);
NativeCall.Void_Call_1(op, tp);
return;
}
}
}