pythonnet/src/runtime/Types/OperatorMethod.cs at v3.2.0-rc1 · pythonnet/pythonnet · GitHub

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using System;

using System.Collections.Generic;

using System.Diagnostics;

using System.Linq;

using System.Reflection;

using System.Text;

namespace Python.Runtime

{

internal static class OperatorMethod

{

/// <summary>

/// Maps the compiled method name in .NET CIL (e.g. op_Addition) to

/// the equivalent Python operator (e.g. __add__) as well as the offset

/// that identifies that operator's slot (e.g. nb_add) in heap space.

/// </summary>

public static Dictionary<string, SlotDefinition> OpMethodMap { get; private set; }

public static Dictionary<string, string> ComparisonOpMap { get; private set; }

public readonly struct SlotDefinition

{

public SlotDefinition(string methodName, int typeOffset)

{

MethodName = methodName;

TypeOffset = typeOffset;

}

public string MethodName { get; }

public int TypeOffset { get; }

}

private static PyObject? _opType;

static OperatorMethod()

{

// .NET operator method names are documented at:

// https://docs.microsoft.com/en-us/dotnet/standard/design-guidelines/operator-overloads

// Python operator methods and slots are documented at:

// https://docs.python.org/3/c-api/typeobj.html

// TODO: Rich compare, inplace operator support

OpMethodMap = new Dictionary<string, SlotDefinition>

{

["op_Addition"] = new SlotDefinition("__add__", TypeOffset.nb_add),

["op_Subtraction"] = new SlotDefinition("__sub__", TypeOffset.nb_subtract),

["op_Multiply"] = new SlotDefinition("__mul__", TypeOffset.nb_multiply),

["op_Division"] = new SlotDefinition("__truediv__", TypeOffset.nb_true_divide),

["op_Modulus"] = new SlotDefinition("__mod__", TypeOffset.nb_remainder),

["op_BitwiseAnd"] = new SlotDefinition("__and__", TypeOffset.nb_and),

["op_BitwiseOr"] = new SlotDefinition("__or__", TypeOffset.nb_or),

["op_ExclusiveOr"] = new SlotDefinition("__xor__", TypeOffset.nb_xor),

["op_LeftShift"] = new SlotDefinition("__lshift__", TypeOffset.nb_lshift),

["op_RightShift"] = new SlotDefinition("__rshift__", TypeOffset.nb_rshift),

["op_OnesComplement"] = new SlotDefinition("__invert__", TypeOffset.nb_invert),

["op_UnaryNegation"] = new SlotDefinition("__neg__", TypeOffset.nb_negative),

["op_UnaryPlus"] = new SlotDefinition("__pos__", TypeOffset.nb_positive),

["__int__"] = new SlotDefinition("__int__", TypeOffset.nb_int),

["__float__"] = new SlotDefinition("__float__", TypeOffset.nb_float),

["__index__"] = new SlotDefinition("__index__", TypeOffset.nb_index),

};

ComparisonOpMap = new Dictionary<string, string>

{

["op_Equality"] = "__eq__",

["op_Inequality"] = "__ne__",

["op_LessThanOrEqual"] = "__le__",

["op_GreaterThanOrEqual"] = "__ge__",

["op_LessThan"] = "__lt__",

["op_GreaterThan"] = "__gt__",

};

}

public static void Initialize()

{

_opType = GetOperatorType();

}

public static void Shutdown()

{

if (_opType != null)

{

_opType.Dispose();

_opType = null;

}

public static bool IsOperatorMethod(MethodBase method)

{

if (!method.IsSpecialName && !method.IsOpsHelper())

{

return false;

}

return OpMethodMap.ContainsKey(method.Name) || ComparisonOpMap.ContainsKey(method.Name);

}

public static bool IsComparisonOp(MethodBase method)

{

return ComparisonOpMap.ContainsKey(method.Name);

}

/// <summary>

/// For the operator methods of a CLR type, set the special slots of the

/// corresponding Python type's operator methods.

/// </summary>

public static void FixupSlots(BorrowedReference pyType, Type clrType)

{

Debug.Assert(_opType != null);

var operatorCandidates = GetOperatorCandidates(clrType);

foreach (var method in operatorCandidates)

{

// We only want to override slots for operators excluding

// comparison operators, which are handled by ClassBase.tp_richcompare.

if (!OpMethodMap.ContainsKey(method.Name))

{

continue;

}

int offset = OpMethodMap[method.Name].TypeOffset;

// Copy the default implementation of e.g. the nb_add slot,

// which simply calls __add__ on the type.

IntPtr func = Util.ReadIntPtr(_opType!, offset);

// Write the slot definition of the target Python type, so

// that we can later modify __add___ and it will be called

// when used with a Python operator.

// https://tenthousandmeters.com/blog/python-behind-the-scenes-6-how-python-object-system-works/

Util.WriteIntPtr(pyType, offset, func);

}

static IEnumerable<MethodInfo> GetOperatorCandidates(Type clrType)

{

const BindingFlags flags = BindingFlags.Public | BindingFlags.Static;

if (clrType.IsEnum)

{

return typeof(EnumOps<>).MakeGenericType(clrType).GetMethods(flags)

.Concat(typeof(FlagEnumOps<>).MakeGenericType(clrType).GetMethods(flags));

}

return clrType.GetMethods(flags);

}

public static string GetPyMethodName(string clrName)

{

if (OpMethodMap.ContainsKey(clrName))

{

return OpMethodMap[clrName].MethodName;

} else

{

return ComparisonOpMap[clrName];

}

private static string GenerateDummyCode()

{

var sb = new StringBuilder();

sb.AppendLine("class OperatorMethod(object):");

foreach (var item in OpMethodMap.Values)

{

string def = string.Format(" def {0}(self, other): pass", item.MethodName);

sb.AppendLine(def);

}

return sb.ToString();

}

private static PyObject GetOperatorType()

{

using var locals = new PyDict();

// A hack way for getting typeobject.c::slotdefs

string code = GenerateDummyCode();

// The resulting OperatorMethod class is stored in a PyDict.

PythonEngine.Exec(code, null, locals);

// Return the class itself, which is a type.

return locals.GetItem("OperatorMethod");

}

public static string ReversePyMethodName(string pyName)

{

return pyName.Insert(2, "r");

}

/// <summary>

/// Check if the method should have a reversed operation.

/// </summary>

/// <param name="method">The operator method.</param>

/// <returns></returns>

public static bool HaveReverse(MethodBase method)

{

var pi = method.GetParameters();

return OpMethodMap.ContainsKey(method.Name) && pi.Length == 2;

}

public static void FilterMethods(MethodBase[] methods, out MethodBase[] forwardMethods, out MethodBase[] reverseMethods)

{

var forwardMethodsList = new List<MethodBase>();

var reverseMethodsList = new List<MethodBase>();

foreach (var method in methods)

{

forwardMethodsList.Add(method);

if (HaveReverse(method))

{

reverseMethodsList.Add(method);

}

forwardMethods = forwardMethodsList.ToArray();

reverseMethods = reverseMethodsList.ToArray();

}

pythonnet/src/runtime/Types/OperatorMethod.cs at v3.2.0-rc1 · pythonnet/pythonnet · GitHub

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