pythonnet/src/runtime/Types/MetaType.cs at master · devtrack/pythonnet · GitHub

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using System;

using System.Collections.Generic;

using System.Diagnostics;

using System.Linq;

using System.Reflection;

using System.Runtime.InteropServices;

using System.Runtime.Serialization;

using Python.Runtime.StateSerialization;

namespace Python.Runtime

{

/// <summary>

/// The managed metatype. This object implements the type of all reflected

/// types. It also provides support for single-inheritance from reflected

/// managed types.

/// </summary>

internal sealed class MetaType : ManagedType

{

#pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.

// set in Initialize

private static PyType PyCLRMetaType;

private static SlotsHolder _metaSlotsHodler;

#pragma warning restore CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.

internal static readonly string[] CustomMethods = new string[]

{

"__instancecheck__",

"__subclasscheck__",

};

/// <summary>

/// Metatype initialization. This bootstraps the CLR metatype to life.

/// </summary>

public static PyType Initialize()

{

PyCLRMetaType = TypeManager.CreateMetaType(typeof(MetaType), out _metaSlotsHodler);

return PyCLRMetaType;

}

public static void Release()

{

if (Runtime.HostedInPython)

{

_metaSlotsHodler.ResetSlots();

}

PyCLRMetaType.Dispose();

}

internal static MetatypeState SaveRuntimeData() => new() { CLRMetaType = PyCLRMetaType };

internal static PyType RestoreRuntimeData(MetatypeState storage)

{

PyCLRMetaType = storage.CLRMetaType;

_metaSlotsHodler = new SlotsHolder(PyCLRMetaType);

TypeManager.InitializeSlots(PyCLRMetaType, typeof(MetaType), _metaSlotsHodler);

IntPtr mdef = Util.ReadIntPtr(PyCLRMetaType, TypeOffset.tp_methods);

foreach (var methodName in CustomMethods)

{

var mi = typeof(MetaType).GetMethod(methodName);

ThunkInfo thunkInfo = Interop.GetThunk(mi);

_metaSlotsHodler.KeeapAlive(thunkInfo);

mdef = TypeManager.WriteMethodDef(mdef, methodName, thunkInfo.Address);

}

return PyCLRMetaType;

}

/// <summary>

/// Metatype __new__ implementation. This is called to create a new

/// class / type when a reflected class is subclassed.

/// </summary>

public static NewReference tp_new(BorrowedReference tp, BorrowedReference args, BorrowedReference kw)

{

var len = Runtime.PyTuple_Size(args);

if (len < 3)

{

return Exceptions.RaiseTypeError("invalid argument list");

}

BorrowedReference name = Runtime.PyTuple_GetItem(args, 0);

BorrowedReference bases = Runtime.PyTuple_GetItem(args, 1);

BorrowedReference dict = Runtime.PyTuple_GetItem(args, 2);

// Extract interface types and base class types.

var interfaces = new List<Type>();

// More than one base type case be declared, but an exception will be thrown

// if more than one is a class/not an interface.

var baseTypes = new List<ClassBase>();

var baseClassCount = Runtime.PyTuple_Size(bases);

if (baseClassCount == 0)

{

return Exceptions.RaiseTypeError("zero base classes ");

}

for (nint i = 0; i < baseClassCount; i++)

{

var baseTypeIt = Runtime.PyTuple_GetItem(bases, (int)i);

if (GetManagedObject(baseTypeIt) is ClassBase classBaseIt)

{

if (!classBaseIt.type.Valid)

{

return Exceptions.RaiseTypeError("Invalid type used as a super type.");

}

if (classBaseIt.type.Value.IsInterface)

{

interfaces.Add(classBaseIt.type.Value);

}

else

{

baseTypes.Add(classBaseIt);

}

else

{

return Exceptions.RaiseTypeError("Non .NET type used as super class for meta type. This is not supported.");

}

// if the base type count is 0, there might still be interfaces to implement.

if (baseTypes.Count == 0)

{

baseTypes.Add(new ClassBase(typeof(object)));

}

// Multiple inheritance is not supported, unless the other types are interfaces

if (baseTypes.Count > 1)

{

var types = string.Join(", ", baseTypes.Select(baseType => baseType.type.Value));

return Exceptions.RaiseTypeError($"Multiple inheritance with managed classes cannot be used. Types: {types} ");

}

// check if the list of interfaces contains no duplicates.

if (interfaces.Distinct().Count() != interfaces.Count)

{

// generate a string containing the problematic types.

var duplicateTypes = interfaces.GroupBy(type => type)

.Where(typeGroup => typeGroup.Count() > 1)

.Select(typeGroup => typeGroup.Key);

var duplicateTypesString = string.Join(", ", duplicateTypes);

return Exceptions.RaiseTypeError($"An interface can only be implemented once. Duplicate types: {duplicateTypesString}");

}

var cb = baseTypes[0];

try

{

if (!cb.CanSubclass())

{

return Exceptions.RaiseTypeError("delegates, enums and array types cannot be subclassed");

}

catch (SerializationException)

{

return Exceptions.RaiseTypeError($"Underlying C# Base class {cb.type} has been deleted");

}

BorrowedReference slots = Runtime.PyDict_GetItem(dict, PyIdentifier.__slots__);

if (slots != null)

{

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 (null != dict)

{

using var clsDict = new PyDict(dict);

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

{

return TypeManager.CreateSubType(name, baseTypes[0], interfaces, clsDict);

}

var base_type = Runtime.PyTuple_GetItem(bases, 0);

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

IntPtr func = Util.ReadIntPtr(Runtime.PyTypeType, TypeOffset.tp_new);

NewReference type = NativeCall.Call_3(func, tp, args, kw);

if (type.IsNull())

{

return default;

}

var flags = PyType.GetFlags(type.Borrow());

if (!flags.HasFlag(TypeFlags.Ready))

throw new NotSupportedException("PyType.tp_new returned an incomplete type");

flags |= TypeFlags.HasClrInstance;

flags |= TypeFlags.HeapType;

flags |= TypeFlags.BaseType;

flags |= TypeFlags.Subclass;

flags |= TypeFlags.HaveGC;

PyType.SetFlags(type.Borrow(), flags);

TypeManager.CopySlot(base_type, type.Borrow(), 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.Borrow(), TypeOffset.tp_traverse);

TypeManager.CopySlot(base_type, type.Borrow(), TypeOffset.tp_clear);

// derived types must have their GCHandle at the same offset as the base types

int clrInstOffset = Util.ReadInt32(base_type, Offsets.tp_clr_inst_offset);

Debug.Assert(clrInstOffset > 0

&& clrInstOffset < Util.ReadInt32(type.Borrow(), TypeOffset.tp_basicsize));

Util.WriteInt32(type.Borrow(), Offsets.tp_clr_inst_offset, clrInstOffset);

// for now, move up hidden handle...

var gc = (GCHandle)Util.ReadIntPtr(base_type, Offsets.tp_clr_inst);

Util.WriteIntPtr(type.Borrow(), Offsets.tp_clr_inst, (IntPtr)GCHandle.Alloc(gc.Target));

Runtime.PyType_Modified(type.Borrow());

return type;

}

public static NewReference tp_alloc(BorrowedReference mt, nint n)

=> Runtime.PyType_GenericAlloc(mt, n);

public static void tp_free(NewReference tp)

{

Runtime.PyObject_GC_Del(tp.Steal());

}

/// <summary>

/// 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 doesn't know.

/// </summary>

public static NewReference tp_call(BorrowedReference tp, BorrowedReference args, BorrowedReference kw)

{

IntPtr tp_new = Util.ReadIntPtr(tp, TypeOffset.tp_new);

if (tp_new == IntPtr.Zero)

{

return Exceptions.RaiseTypeError("invalid object");

}

using NewReference obj = NativeCall.Call_3(tp_new, tp, args, kw);

if (obj.IsNull())

{

return default;

}

var type = GetManagedObject(tp)!;

return type.Init(obj.Borrow(), args, kw)

? obj.Move()

: default;

}

/// <summary>

/// 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.

/// </summary>

public static int tp_setattro(BorrowedReference tp, BorrowedReference name, BorrowedReference value)

{

BorrowedReference descr = Runtime._PyType_Lookup(tp, name);

if (descr != null)

{

BorrowedReference dt = Runtime.PyObject_TYPE(descr);

if (dt == Runtime.PyWrapperDescriptorType

|| dt == Runtime.PyMethodType

|| typeof(ExtensionType).IsInstanceOfType(GetManagedObject(descr))

)

{

IntPtr fp = Util.ReadIntPtr(dt, TypeOffset.tp_descr_set);

if (fp != IntPtr.Zero)

{

return NativeCall.Int_Call_3(fp, descr, name, value);

}

Exceptions.SetError(Exceptions.AttributeError, "attribute is read-only");

return -1;

}

int res = Runtime.PyObject_GenericSetAttr(tp, name, value);

Runtime.PyType_Modified(tp);

return res;

}

/// <summary>

/// The metatype has to implement [] semantics for generic types, so

/// here we just delegate to the generic type def implementation. Its

/// own mp_subscript

/// </summary>

public static NewReference mp_subscript(BorrowedReference tp, BorrowedReference idx)

{

if (GetManagedObject(tp) is ClassBase cb)

{

return cb.type_subscript(idx);

}

return Exceptions.RaiseTypeError("unsubscriptable object");

}

/// <summary>

/// Dealloc implementation. This is called when a Python type generated

/// by this metatype is no longer referenced from the Python runtime.

/// </summary>

public static void tp_dealloc(NewReference lastRef)

{

var weakrefs = Runtime.PyObject_GetWeakRefList(lastRef.Borrow());

if (weakrefs != null)

{

Runtime.PyObject_ClearWeakRefs(lastRef.Borrow());

}

// Fix this when we dont cheat on the handle for subclasses!

var flags = PyType.GetFlags(lastRef.Borrow());

if ((flags & TypeFlags.Subclass) == 0)

{

TryGetGCHandle(lastRef.Borrow())?.Free();

#if DEBUG

// prevent ExecutionEngineException in debug builds in case we have a bug

// this would allow using managed debugger to investigate the issue

SetGCHandle(lastRef.Borrow(), default);

#endif

}

var op = Runtime.PyObject_TYPE(lastRef.Borrow());

Debug.Assert(Runtime.PyCLRMetaType is null || Runtime.PyCLRMetaType == op);

var builtinType = Runtime.PyObject_TYPE(Runtime.PyObject_TYPE(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.

IntPtr tp_dealloc = Util.ReadIntPtr(builtinType, TypeOffset.tp_dealloc);

NativeCall.CallDealloc(tp_dealloc, lastRef.Steal());

// We must decref our type.

// type_dealloc from PyType will use it to get tp_free so we must keep the value

Runtime.XDecref(StolenReference.DangerousFromPointer(op.DangerousGetAddress()));

}

private static NewReference DoInstanceCheck(BorrowedReference tp, BorrowedReference args, bool checkType)

{

if (GetManagedObject(tp) is not ClassBase cb || !cb.type.Valid)

{

return new NewReference(Runtime.PyFalse);

}

using var argsObj = new PyList(args);

if (argsObj.Length() != 1)

{

return Exceptions.RaiseTypeError("Invalid parameter count");

}

PyObject arg = argsObj[0];

var otherType = checkType ? arg : arg.GetPythonType();

if (Runtime.PyObject_TYPE(otherType) != PyCLRMetaType)

{

return new NewReference(Runtime.PyFalse);

}

if (GetManagedObject(otherType) is ClassBase otherCb && otherCb.type.Valid)

{

return Converter.ToPython(cb.type.Value.IsAssignableFrom(otherCb.type.Value));

}

return new NewReference(Runtime.PyFalse);

}

public static NewReference __instancecheck__(BorrowedReference tp, BorrowedReference args)

{

return DoInstanceCheck(tp, args, false);

}

public static NewReference __subclasscheck__(BorrowedReference tp, BorrowedReference args)

{

return DoInstanceCheck(tp, args, true);

}

pythonnet/src/runtime/Types/MetaType.cs at master · devtrack/pythonnet · GitHub

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