pythonnet/src/runtime/Types/MethodBinding.cs at v3.0.1 · pythonnet/pythonnet · GitHub

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using System;

using System.Collections.Generic;

using System.Diagnostics;

using System.Linq;

using System.Reflection;

namespace Python.Runtime

{

using MaybeMethodInfo = MaybeMethodBase<MethodBase>;

/// <summary>

/// Implements a Python binding type for CLR methods. These work much like

/// standard Python method bindings, but the same type is used to bind

/// both static and instance methods.

/// </summary>

[Serializable]

internal class MethodBinding : ExtensionType

{

internal MaybeMethodInfo info;

internal MethodObject m;

internal PyObject? target;

internal PyType? targetType;

public MethodBinding(MethodObject m, PyObject? target, PyType? targetType = null)

{

this.target = target;

this.targetType = targetType ?? target?.GetPythonType();

this.info = null;

this.m = m;

}

/// <summary>

/// Implement binding of generic methods using the subscript syntax [].

/// </summary>

public static NewReference mp_subscript(BorrowedReference tp, BorrowedReference idx)

{

var self = (MethodBinding)GetManagedObject(tp)!;

Type[]? types = Runtime.PythonArgsToTypeArray(idx);

if (types == null)

{

return Exceptions.RaiseTypeError("type(s) expected");

}

MethodBase[] overloads = self.m.IsInstanceConstructor

? self.m.type.Value.GetConstructor(types) is { } ctor

? new[] { ctor }

: Array.Empty<MethodBase>()

: MethodBinder.MatchParameters(self.m.info, types);

if (overloads.Length == 0)

{

return Exceptions.RaiseTypeError("No match found for given type params");

}

MethodObject overloaded = self.m.WithOverloads(overloads);

var mb = new MethodBinding(overloaded, self.target, self.targetType);

return mb.Alloc();

}

PyObject Signature

{

get

{

var infos = this.info.Valid ? new[] { this.info.Value } : this.m.info;

Type type = infos.Select(i => i.DeclaringType)

.OrderByDescending(t => t, new TypeSpecificityComparer())

.First();

infos = infos.Where(info => info.DeclaringType == type).ToArray();

// this is a primitive version

// the overload with the maximum number of parameters should be used

MethodBase primary = infos.OrderByDescending(i => i.GetParameters().Length).First();

var primaryParameters = primary.GetParameters();

PyObject signatureClass = Runtime.InspectModule.GetAttr("Signature");

using var parameters = new PyList();

using var parameterClass = primaryParameters.Length > 0 ? Runtime.InspectModule.GetAttr("Parameter") : null;

using var positionalOrKeyword = parameterClass?.GetAttr("POSITIONAL_OR_KEYWORD");

for (int i = 0; i < primaryParameters.Length; i++)

{

var parameter = primaryParameters[i];

var alternatives = infos.Select(info =>

{

ParameterInfo[] altParamters = info.GetParameters();

return i < altParamters.Length ? altParamters[i] : null;

}).WhereNotNull();

using var defaultValue = alternatives

.Select(alternative => alternative!.DefaultValue != DBNull.Value ? alternative.DefaultValue.ToPython() : null)

.FirstOrDefault(v => v != null) ?? parameterClass?.GetAttr("empty");

if (alternatives.Any(alternative => alternative.Name != parameter.Name)

|| positionalOrKeyword is null)

{

return signatureClass.Invoke();

}

using var args = new PyTuple(new[] { parameter.Name.ToPython(), positionalOrKeyword });

using var kw = new PyDict();

if (defaultValue is not null)

{

kw["default"] = defaultValue;

}

using var parameterInfo = parameterClass!.Invoke(args: args, kw: kw);

parameters.Append(parameterInfo);

}

// TODO: add return annotation

return signatureClass.Invoke(parameters);

}

struct TypeSpecificityComparer : IComparer<Type>

{

public int Compare(Type a, Type b)

{

if (a == b) return 0;

if (a.IsSubclassOf(b)) return 1;

if (b.IsSubclassOf(a)) return -1;

throw new NotSupportedException();

}

/// <summary>

/// MethodBinding __getattribute__ implementation.

/// </summary>

public static NewReference tp_getattro(BorrowedReference ob, BorrowedReference key)

{

var self = (MethodBinding)GetManagedObject(ob)!;

if (!Runtime.PyString_Check(key))

{

Exceptions.SetError(Exceptions.TypeError, "string expected");

return default;

}

string? name = InternString.GetManagedString(key);

switch (name)

{

case "__doc__":

return self.m.GetDocString();

// FIXME: deprecate __overloads__ soon...

case "__overloads__":

case "Overloads":

var om = new OverloadMapper(self.m, self.target);

return om.Alloc();

case "__signature__" when Runtime.InspectModule is not null:

var sig = self.Signature;

if (sig is null)

{

return Runtime.PyObject_GenericGetAttr(ob, key);

}

return sig.NewReferenceOrNull();

case "__name__":

return self.m.GetName();

default:

return Runtime.PyObject_GenericGetAttr(ob, key);

}

/// <summary>

/// MethodBinding __call__ implementation.

/// </summary>

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

{

var self = (MethodBinding)GetManagedObject(ob)!;

// This works around a situation where the wrong generic method is picked,

// for example this method in the tests: string Overloaded<T>(int arg1, int arg2, string arg3)

if (self.info.Valid)

{

var info = self.info.Value;

if (info.IsGenericMethod)

{

Type[]? sigTp = Runtime.PythonArgsToTypeArray(args, true);

if (sigTp != null)

{

Type[] genericTp = info.GetGenericArguments();

MethodInfo? betterMatch = MethodBinder.MatchSignatureAndParameters(self.m.info, genericTp, sigTp);

if (betterMatch != null)

{

self.info = betterMatch;

}

// This supports calling a method 'unbound', passing the instance

// as the first argument. Note that this is not supported if any

// of the overloads are static since we can't know if the intent

// was to call the static method or the unbound instance method.

var disposeList = new List<PyObject>();

try

{

PyObject? target = self.target;

if (target is null && !self.m.IsStatic())

{

var len = Runtime.PyTuple_Size(args);

if (len < 1)

{

Exceptions.SetError(Exceptions.TypeError, "not enough arguments");

return default;

}

target = new PyObject(Runtime.PyTuple_GetItem(args, 0));

disposeList.Add(target);

var unboundArgs = Runtime.PyTuple_GetSlice(args, 1, len).MoveToPyObject();

disposeList.Add(unboundArgs);

args = unboundArgs;

}

// if the class is a IPythonDerivedClass and target is not the same as self.targetType

// (eg if calling the base class method) then call the original base class method instead

// of the target method.

IntPtr superType = IntPtr.Zero;

if (target is not null && Runtime.PyObject_TYPE(target) != self.targetType!)

{

var inst = GetManagedObject(target) as CLRObject;

if (inst?.inst is IPythonDerivedType)

{

if (GetManagedObject(self.targetType!) is ClassBase baseType && baseType.type.Valid)

{

var baseMethodName = $"_{baseType.type.Value.Name}__{self.m.name}";

using var baseMethod = Runtime.PyObject_GetAttrString(target, baseMethodName);

if (!baseMethod.IsNull())

{

if (GetManagedObject(baseMethod.Borrow()) is MethodBinding baseSelf)

{

self = baseSelf;

}

else

{

Runtime.PyErr_Clear();

}

return self.m.Invoke(target is null ? BorrowedReference.Null : target, args, kw, self.info.UnsafeValue);

}

finally

{

foreach (var ptr in disposeList)

{

ptr.Dispose();

}

/// <summary>

/// MethodBinding __hash__ implementation.

/// </summary>

public static nint tp_hash(BorrowedReference ob)

{

var self = (MethodBinding)GetManagedObject(ob)!;

nint x = 0;

if (self.target is not null)

{

x = Runtime.PyObject_Hash(self.target);

if (x == -1)

{

return x;

}

nint y = self.m.GetHashCode();

return x ^ y;

}

/// <summary>

/// MethodBinding __repr__ implementation.

/// </summary>

public static NewReference tp_repr(BorrowedReference ob)

{

var self = (MethodBinding)GetManagedObject(ob)!;

string type = self.target is null ? "unbound" : "bound";

string name = self.m.name;

return Runtime.PyString_FromString($"<{type} method '{name}'>");

}

pythonnet/src/runtime/Types/MethodBinding.cs at v3.0.1 · pythonnet/pythonnet · GitHub

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