namespace Python.Runtime.Native
{
using System;
using System.Globalization;
using System.Linq;
using System.Reflection;
static class ABI
{
public static int RefCountOffset { get; } = GetRefCountOffset();
public static int ObjectHeadOffset => RefCountOffset;
internal static void Initialize(Version version)
{
string offsetsClassSuffix = string.Format(CultureInfo.InvariantCulture,
"{0}{1}", version.Major, version.Minor);
var thisAssembly = Assembly.GetExecutingAssembly();
const string nativeTypeOffsetClassName = "Python.Runtime.NativeTypeOffset";
string className = "Python.Runtime.TypeOffset" + offsetsClassSuffix;
Type nativeOffsetsClass = thisAssembly.GetType(nativeTypeOffsetClassName, throwOnError: false);
Type typeOffsetsClass =
// Try platform native offsets first. It is only present when generated by setup.py
nativeOffsetsClass ?? thisAssembly.GetType(className, throwOnError: false);
if (typeOffsetsClass is null)
{
var types = thisAssembly.GetTypes().Select(type => type.Name).Where(name => name.StartsWith("TypeOffset"));
string message = $"Searching for {className}, found {string.Join(",", types)}.";
throw new NotSupportedException($"Python ABI v{version} is not supported: {message}");
}
var typeOffsets = (ITypeOffsets)Activator.CreateInstance(typeOffsetsClass);
TypeOffset.Use(typeOffsets, nativeOffsetsClass == null ? ObjectHeadOffset : 0);
}
static unsafe int GetRefCountOffset()
{
using var tempObject = Runtime.PyList_New(0);
IntPtr* tempPtr = (IntPtr*)tempObject.DangerousGetAddress();
int offset = 0;
while(tempPtr[offset] != (IntPtr)1)
{
offset++;
if (offset > 100)
throw new InvalidProgramException("PyObject_HEAD could not be found withing reasonable distance from the start of PyObject");
}
return offset * IntPtr.Size;
}
}
}