// ==========================================================================

// 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__"

);

}

// If __assembly__ or __namespace__ are in the class dictionary then create

// a managed sub type.

// This creates a new managed type that can be used from .net to call back

// into python.

if (IntPtr.Zero != dict) {

Runtime.Incref(dict);

using (PyDict clsDict = new PyDict(dict)) {

if (clsDict.HasKey("__assembly__") || clsDict.HasKey("__namespace__"))

return TypeManager.CreateSubType(name, base_type, dict);

}

}

// otherwise just create a basic type without reflecting back into the managed side.

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);

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;

}

}

}