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using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Runtime.InteropServices;
using Python.Runtime.Platform;
using Python.Runtime.Slots;
namespace Python.Runtime
{
/// <summary>
/// The TypeManager class is responsible for building binary-compatible
/// Python type objects that are implemented in managed code.
/// </summary>
internal class TypeManager
{
private static BindingFlags tbFlags;
private static Dictionary<Type, IntPtr> cache;
static TypeManager()
{
tbFlags = BindingFlags.Public | BindingFlags.Static;
cache = new Dictionary<Type, IntPtr>(128);
}
public static void Reset()
{
cache = new Dictionary<Type, IntPtr>(128);
}
/// <summary>
/// Given a managed Type derived from ExtensionType, get the handle to
/// a Python type object that delegates its implementation to the Type
/// object. These Python type instances are used to implement internal
/// descriptor and utility types like ModuleObject, PropertyObject, etc.
/// </summary>
internal static IntPtr GetTypeHandle(Type type)
{
// Note that these types are cached with a refcount of 1, so they
// effectively exist until the CPython runtime is finalized.
IntPtr handle;
cache.TryGetValue(type, out handle);
if (handle != IntPtr.Zero)
{
return handle;
}
handle = CreateType(type);
cache[type] = handle;
return handle;
}
/// <summary>
/// Get the handle of a Python type that reflects the given CLR type.
/// The given ManagedType instance is a managed object that implements
/// the appropriate semantics in Python for the reflected managed type.
/// </summary>
internal static IntPtr GetTypeHandle(ManagedType obj, Type type)
{
IntPtr handle;
cache.TryGetValue(type, out handle);
if (handle != IntPtr.Zero)
{
return handle;
}
handle = CreateType(obj, type);
cache[type] = handle;
return handle;
}
/// <summary>
/// The following CreateType implementations do the necessary work to
/// create Python types to represent managed extension types, reflected
/// types, subclasses of reflected types and the managed metatype. The
/// dance is slightly different for each kind of type due to different
/// behavior needed and the desire to have the existing Python runtime
/// do as much of the allocation and initialization work as possible.
/// </summary>
internal static IntPtr CreateType(Type impl)
{
IntPtr type = AllocateTypeObject(impl.Name);
int ob_size = ObjectOffset.Size(type);
// Set tp_basicsize to the size of our managed instance objects.
Marshal.WriteIntPtr(type, TypeOffset.tp_basicsize, (IntPtr)ob_size);
var offset = (IntPtr)ObjectOffset.TypeDictOffset(type);
Marshal.WriteIntPtr(type, TypeOffset.tp_dictoffset, offset);
InitializeSlots(type, impl);
int flags = TypeFlags.Default | TypeFlags.Managed |
TypeFlags.HeapType | TypeFlags.HaveGC;
Util.WriteCLong(type, TypeOffset.tp_flags, flags);
Runtime.PyType_Ready(type);
IntPtr dict = Marshal.ReadIntPtr(type, TypeOffset.tp_dict);
IntPtr mod = Runtime.PyString_FromString("CLR");
Runtime.PyDict_SetItemString(dict, "__module__", mod);
InitMethods(type, impl);
return type;
}
internal static IntPtr CreateType(ManagedType impl, Type clrType)
{
// Cleanup the type name to get rid of funny nested type names.
string name = "CLR." + clrType.FullName;
int i = name.LastIndexOf('+');
if (i > -1)
{
name = name.Substring(i + 1);
}
i = name.LastIndexOf('.');
if (i > -1)
{
name = name.Substring(i + 1);
}
IntPtr base_ = IntPtr.Zero;
int ob_size = ObjectOffset.Size(Runtime.PyTypeType);
// XXX Hack, use a different base class for System.Exception
// Python 2.5+ allows new style class exceptions but they *must*
// subclass BaseException (or better Exception).
if (typeof(Exception).IsAssignableFrom(clrType))
{
ob_size = ObjectOffset.Size(Exceptions.Exception);
}
int tp_dictoffset = ob_size + ManagedDataOffsets.ob_dict;
if (clrType == typeof(Exception))
{
base_ = Exceptions.Exception;
}
else if (clrType.BaseType != null)
{
ClassBase bc = ClassManager.GetClass(clrType.BaseType);
base_ = bc.pyHandle;
}
IntPtr type = AllocateTypeObject(name);
Marshal.WriteIntPtr(type, TypeOffset.ob_type, Runtime.PyCLRMetaType);
Runtime.XIncref(Runtime.PyCLRMetaType);
Marshal.WriteIntPtr(type, TypeOffset.tp_basicsize, (IntPtr)ob_size);
Marshal.WriteIntPtr(type, TypeOffset.tp_itemsize, IntPtr.Zero);
Marshal.WriteIntPtr(type, TypeOffset.tp_dictoffset, (IntPtr)tp_dictoffset);
// add a __len__ slot for inheritors of ICollection and ICollection<>
if (typeof(ICollection).IsAssignableFrom(clrType) || clrType.GetInterfaces().Any(x => x.IsGenericType && x.GetGenericTypeDefinition() == typeof(ICollection<>)))
{
InitializeSlot(type, TypeOffset.mp_length, typeof(mp_length_slot).GetMethod(nameof(mp_length_slot.mp_length)));
}
// we want to do this after the slot stuff above in case the class itself implements a slot method
InitializeSlots(type, impl.GetType());
if (base_ != IntPtr.Zero)
{
Marshal.WriteIntPtr(type, TypeOffset.tp_base, base_);
Runtime.XIncref(base_);
}
int flags = TypeFlags.Default;
flags |= TypeFlags.Managed;
flags |= TypeFlags.HeapType;
flags |= TypeFlags.BaseType;
flags |= TypeFlags.HaveGC;
Util.WriteCLong(type, TypeOffset.tp_flags, flags);
// Leverage followup initialization from the Python runtime. Note
// that the type of the new type must PyType_Type at the time we
// call this, else PyType_Ready will skip some slot initialization.
Runtime.PyType_Ready(type);
IntPtr dict = Marshal.ReadIntPtr(type, TypeOffset.tp_dict);
string mn = clrType.Namespace ?? "";
IntPtr mod = Runtime.PyString_FromString(mn);
Runtime.PyDict_SetItemString(dict, "__module__", mod);
// Hide the gchandle of the implementation in a magic type slot.
GCHandle gc = GCHandle.Alloc(impl);
Marshal.WriteIntPtr(type, TypeOffset.magic(), (IntPtr)gc);
// Set the handle attributes on the implementing instance.
impl.tpHandle = Runtime.PyCLRMetaType;
impl.gcHandle = gc;
impl.pyHandle = type;
//DebugUtil.DumpType(type);
return type;
}
static void InitializeSlot(IntPtr type, int slotOffset, MethodInfo method)
{
var thunk = Interop.GetThunk(method);
Marshal.WriteIntPtr(type, slotOffset, thunk.Address);
}
internal static IntPtr CreateSubType(IntPtr py_name, IntPtr py_base_type, IntPtr py_dict)
{
// Utility to create a subtype of a managed type with the ability for the
// a python subtype able to override the managed implementation
string name = Runtime.GetManagedString(py_name);
// the derived class can have class attributes __assembly__ and __module__ which
// control the name of the assembly and module the new type is created in.
object assembly = null;
object namespaceStr = null;
var disposeList = new List<PyObject>();
try
{
var assemblyKey = new PyObject(Converter.ToPython("__assembly__", typeof(string)));
disposeList.Add(assemblyKey);
if (0 != Runtime.PyMapping_HasKey(py_dict, assemblyKey.Handle))
{
var pyAssembly = new PyObject(Runtime.PyDict_GetItem(py_dict, assemblyKey.Handle));
Runtime.XIncref(pyAssembly.Handle);
disposeList.Add(pyAssembly);
if (!Converter.ToManagedValue(pyAssembly.Handle, typeof(string), out assembly, false))
{
throw new InvalidCastException("Couldn't convert __assembly__ value to string");
}
}
var namespaceKey = new PyObject(Converter.ToPythonImplicit("__namespace__"));
disposeList.Add(namespaceKey);
if (0 != Runtime.PyMapping_HasKey(py_dict, namespaceKey.Handle))
{
var pyNamespace = new PyObject(Runtime.PyDict_GetItem(py_dict, namespaceKey.Handle));
Runtime.XIncref(pyNamespace.Handle);
disposeList.Add(pyNamespace);
if (!Converter.ToManagedValue(pyNamespace.Handle, typeof(string), out namespaceStr, false))
{
throw new InvalidCastException("Couldn't convert __namespace__ value to string");
}
}
}
finally
{
foreach (PyObject o in disposeList)
{
o.Dispose();
}
}
// create the new managed type subclassing the base managed type
var baseClass = ManagedType.GetManagedObject(py_base_type) as ClassBase;
if (null == baseClass)
{
return Exceptions.RaiseTypeError("invalid base class, expected CLR class type");
}
try
{
Type subType = ClassDerivedObject.CreateDerivedType(name,
baseClass.type,
py_dict,
(string)namespaceStr,
(string)assembly);
// create the new ManagedType and python type
ClassBase subClass = ClassManager.GetClass(subType);
IntPtr py_type = GetTypeHandle(subClass, subType);
// by default the class dict will have all the C# methods in it, but as this is a
// derived class we want the python overrides in there instead if they exist.
IntPtr cls_dict = Marshal.ReadIntPtr(py_type, TypeOffset.tp_dict);
Runtime.PyDict_Update(cls_dict, py_dict);
// Update the __classcell__ if it exists
var cell = new BorrowedReference(Runtime.PyDict_GetItemString(cls_dict, "__classcell__"));
if (!cell.IsNull)
{
Runtime.PyCell_Set(cell, py_type);
Runtime.PyDict_DelItemString(cls_dict, "__classcell__");
}
return py_type;
}
catch (Exception e)
{
return Exceptions.RaiseTypeError(e.Message);
}
}
internal static IntPtr WriteMethodDef(IntPtr mdef, IntPtr name, IntPtr func, int flags, IntPtr doc)
{
Marshal.WriteIntPtr(mdef, name);
Marshal.WriteIntPtr(mdef, 1 * IntPtr.Size, func);
Marshal.WriteInt32(mdef, 2 * IntPtr.Size, flags);
Marshal.WriteIntPtr(mdef, 3 * IntPtr.Size, doc);
return mdef + 4 * IntPtr.Size;
}
internal static IntPtr WriteMethodDef(IntPtr mdef, string name, IntPtr func, int flags = 0x0001,
string doc = null)
{
IntPtr namePtr = Marshal.StringToHGlobalAnsi(name);
IntPtr docPtr = doc != null ? Marshal.StringToHGlobalAnsi(doc) : IntPtr.Zero;
return WriteMethodDef(mdef, namePtr, func, flags, docPtr);
}
internal static IntPtr WriteMethodDefSentinel(IntPtr mdef)
{
return WriteMethodDef(mdef, IntPtr.Zero, IntPtr.Zero, 0, IntPtr.Zero);
}
internal static IntPtr CreateMetaType(Type impl)
{
// The managed metatype is functionally little different than the
// standard Python metatype (PyType_Type). It overrides certain of
// the standard type slots, and has to subclass PyType_Type for
// certain functions in the C runtime to work correctly with it.
IntPtr type = AllocateTypeObject("CLR Metatype");
IntPtr py_type = Runtime.PyTypeType;
Marshal.WriteIntPtr(type, TypeOffset.tp_base, py_type);
Runtime.XIncref(py_type);
// Slots will inherit from TypeType, it's not neccesary for setting them.
// Inheried slots:
// tp_basicsize, tp_itemsize,
// tp_dictoffset, tp_weaklistoffset,
// tp_traverse, tp_clear, tp_is_gc, etc.
// Override type slots with those of the managed implementation.
InitializeSlots(type, impl);
int flags = TypeFlags.Default;
flags |= TypeFlags.Managed;
flags |= TypeFlags.HeapType;
flags |= TypeFlags.HaveGC;
Util.WriteCLong(type, TypeOffset.tp_flags, flags);
// We need space for 3 PyMethodDef structs, each of them
// 4 int-ptrs in size.
IntPtr mdef = Runtime.PyMem_Malloc(3 * 4 * IntPtr.Size);
IntPtr mdefStart = mdef;
ThunkInfo thunkInfo = Interop.GetThunk(typeof(MetaType).GetMethod("__instancecheck__"), "BinaryFunc");
mdef = WriteMethodDef(
mdef,
"__instancecheck__",
thunkInfo.Address
);
thunkInfo = Interop.GetThunk(typeof(MetaType).GetMethod("__subclasscheck__"), "BinaryFunc");
mdef = WriteMethodDef(
mdef,
"__subclasscheck__",
thunkInfo.Address
);
// FIXME: mdef is not used
mdef = WriteMethodDefSentinel(mdef);
Marshal.WriteIntPtr(type, TypeOffset.tp_methods, mdefStart);
Runtime.PyType_Ready(type);
IntPtr dict = Marshal.ReadIntPtr(type, TypeOffset.tp_dict);
IntPtr mod = Runtime.PyString_FromString("CLR");
Runtime.PyDict_SetItemString(dict, "__module__", mod);
//DebugUtil.DumpType(type);
return type;
}
internal static IntPtr BasicSubType(string name, IntPtr base_, Type impl)
{
// Utility to create a subtype of a std Python type, but with
// a managed type able to override implementation
IntPtr type = AllocateTypeObject(name);
//Marshal.WriteIntPtr(type, TypeOffset.tp_basicsize, (IntPtr)obSize);
//Marshal.WriteIntPtr(type, TypeOffset.tp_itemsize, IntPtr.Zero);
//IntPtr offset = (IntPtr)ObjectOffset.ob_dict;
//Marshal.WriteIntPtr(type, TypeOffset.tp_dictoffset, offset);
//IntPtr dc = Runtime.PyDict_Copy(dict);
//Marshal.WriteIntPtr(type, TypeOffset.tp_dict, dc);
Marshal.WriteIntPtr(type, TypeOffset.tp_base, base_);
Runtime.XIncref(base_);
int flags = TypeFlags.Default;
flags |= TypeFlags.Managed;
flags |= TypeFlags.HeapType;
flags |= TypeFlags.HaveGC;
Util.WriteCLong(type, TypeOffset.tp_flags, flags);
CopySlot(base_, type, TypeOffset.tp_traverse);
CopySlot(base_, type, TypeOffset.tp_clear);
CopySlot(base_, type, TypeOffset.tp_is_gc);
InitializeSlots(type, impl);
Runtime.PyType_Ready(type);
IntPtr tp_dict = Marshal.ReadIntPtr(type, TypeOffset.tp_dict);
IntPtr mod = Runtime.PyString_FromString("CLR");
Runtime.PyDict_SetItemString(tp_dict, "__module__", mod);
return type;
}
/// <summary>
/// Utility method to allocate a type object & do basic initialization.
/// </summary>
internal static IntPtr AllocateTypeObject(string name)
{
IntPtr type = Runtime.PyType_GenericAlloc(Runtime.PyTypeType, 0);
// Cheat a little: we'll set tp_name to the internal char * of
// the Python version of the type name - otherwise we'd have to
// allocate the tp_name and would have no way to free it.
#if PYTHON3
IntPtr temp = Runtime.PyUnicode_FromString(name);
IntPtr raw = Runtime.PyUnicode_AsUTF8(temp);
#elif PYTHON2
IntPtr temp = Runtime.PyString_FromString(name);
IntPtr raw = Runtime.PyString_AsString(temp);
#endif
Marshal.WriteIntPtr(type, TypeOffset.tp_name, raw);
Marshal.WriteIntPtr(type, TypeOffset.name, temp);
#if PYTHON3
Marshal.WriteIntPtr(type, TypeOffset.qualname, temp);
#endif
long ptr = type.ToInt64(); // 64-bit safe
temp = new IntPtr(ptr + TypeOffset.nb_add);
Marshal.WriteIntPtr(type, TypeOffset.tp_as_number, temp);
temp = new IntPtr(ptr + TypeOffset.sq_length);
Marshal.WriteIntPtr(type, TypeOffset.tp_as_sequence, temp);
temp = new IntPtr(ptr + TypeOffset.mp_length);
Marshal.WriteIntPtr(type, TypeOffset.tp_as_mapping, temp);
#if PYTHON3
temp = new IntPtr(ptr + TypeOffset.bf_getbuffer);
#elif PYTHON2
temp = new IntPtr(ptr + TypeOffset.bf_getreadbuffer);
#endif
Marshal.WriteIntPtr(type, TypeOffset.tp_as_buffer, temp);
return type;
}
#region Native Code Page
/// <summary>
/// Initialized by InitializeNativeCodePage.
///
/// This points to a page of memory allocated using mmap or VirtualAlloc
/// (depending on the system), and marked read and execute (not write).
/// Very much on purpose, the page is *not* released on a shutdown and
/// is instead leaked. See the TestDomainReload test case.
///
/// The contents of the page are two native functions: one that returns 0,
/// one that returns 1.
///
/// If python didn't keep its gc list through a Py_Finalize we could remove
/// this entire section.
/// </summary>
internal static IntPtr NativeCodePage = IntPtr.Zero;
/// <summary>
/// Structure to describe native code.
///
/// Use NativeCode.Active to get the native code for the current platform.
///
/// Generate the code by creating the following C code:
/// <code>
/// int Return0() { return 0; }
/// int Return1() { return 1; }
/// </code>
/// Then compiling on the target platform, e.g. with gcc or clang:
/// <code>cc -c -fomit-frame-pointer -O2 foo.c</code>
/// And then analyzing the resulting functions with a hex editor, e.g.:
/// <code>objdump -disassemble foo.o</code>
/// </summary>
internal class NativeCode
{
/// <summary>
/// The code, as a string of bytes.
/// </summary>
public byte[] Code { get; private set; }
/// <summary>
/// Where does the "return 0" function start?
/// </summary>
public int Return0 { get; private set; }
/// <summary>
/// Where does the "return 1" function start?
/// </summary>
public int Return1 { get; private set; }
public static NativeCode Active
{
get
{
switch (Runtime.Machine)
{
case MachineType.i386:
return I386;
case MachineType.x86_64:
return X86_64;
default:
return null;
}
}
}
/// <summary>
/// Code for x86_64. See the class comment for how it was generated.
/// </summary>
public static readonly NativeCode X86_64 = new NativeCode()
{
Return0 = 0x10,
Return1 = 0,
Code = new byte[]
{
// First Return1:
0xb8, 0x01, 0x00, 0x00, 0x00, // movl $1, %eax
0xc3, // ret
// Now some padding so that Return0 can be 16-byte-aligned.
// I put Return1 first so there's not as much padding to type in.
0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00, // nop
// Now Return0.
0x31, 0xc0, // xorl %eax, %eax
0xc3, // ret
}
};
/// <summary>
/// Code for X86.
///
/// It's bitwise identical to X86_64, so we just point to it.
/// <see cref="NativeCode.X86_64"/>
/// </summary>
public static readonly NativeCode I386 = X86_64;
}
/// <summary>
/// Platform-dependent mmap and mprotect.
/// </summary>
internal interface IMemoryMapper
{
/// <summary>
/// Map at least numBytes of memory. Mark the page read-write (but not exec).
/// </summary>
IntPtr MapWriteable(int numBytes);
/// <summary>
/// Sets the mapped memory to be read-exec (but not write).
/// </summary>
void SetReadExec(IntPtr mappedMemory, int numBytes);
}
class WindowsMemoryMapper : IMemoryMapper
{
const UInt32 MEM_COMMIT = 0x1000;
const UInt32 MEM_RESERVE = 0x2000;
const UInt32 PAGE_READWRITE = 0x04;
const UInt32 PAGE_EXECUTE_READ = 0x20;
[DllImport("kernel32.dll")]
static extern IntPtr VirtualAlloc(IntPtr lpAddress, IntPtr dwSize, UInt32 flAllocationType, UInt32 flProtect);
[DllImport("kernel32.dll")]
static extern bool VirtualProtect(IntPtr lpAddress, IntPtr dwSize, UInt32 flNewProtect, out UInt32 lpflOldProtect);
public IntPtr MapWriteable(int numBytes)
{
return VirtualAlloc(IntPtr.Zero, new IntPtr(numBytes),
MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
}
public void SetReadExec(IntPtr mappedMemory, int numBytes)
{
UInt32 _;
VirtualProtect(mappedMemory, new IntPtr(numBytes), PAGE_EXECUTE_READ, out _);
}
}
class UnixMemoryMapper : IMemoryMapper
{
const int PROT_READ = 0x1;
const int PROT_WRITE = 0x2;
const int PROT_EXEC = 0x4;
const int MAP_PRIVATE = 0x2;
int MAP_ANONYMOUS
{
get
{
switch (Runtime.OperatingSystem)
{
case OperatingSystemType.Darwin:
return 0x1000;
case OperatingSystemType.Linux:
return 0x20;
default:
throw new NotImplementedException(
$"mmap is not supported on {Runtime.OperatingSystem}"
);
}
}
}
[DllImport("libc")]
static extern IntPtr mmap(IntPtr addr, IntPtr len, int prot, int flags, int fd, IntPtr offset);
[DllImport("libc")]
static extern int mprotect(IntPtr addr, IntPtr len, int prot);
public IntPtr MapWriteable(int numBytes)
{
// MAP_PRIVATE must be set on linux, even though MAP_ANON implies it.
// It doesn't hurt on darwin, so just do it.
return mmap(IntPtr.Zero, new IntPtr(numBytes), PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, IntPtr.Zero);
}
public void SetReadExec(IntPtr mappedMemory, int numBytes)
{
mprotect(mappedMemory, new IntPtr(numBytes), PROT_READ | PROT_EXEC);
}
}
internal static IMemoryMapper CreateMemoryMapper()
{
switch (Runtime.OperatingSystem)
{
case OperatingSystemType.Darwin:
case OperatingSystemType.Linux:
return new UnixMemoryMapper();
case OperatingSystemType.Windows:
return new WindowsMemoryMapper();
default:
throw new NotImplementedException(
$"No support for {Runtime.OperatingSystem}"
);
}
}
/// <summary>
/// Initializes the native code page.
///
/// Safe to call if we already initialized (this function is idempotent).
/// <see cref="NativeCodePage"/>
/// </summary>
internal static void InitializeNativeCodePage()
{
// Do nothing if we already initialized.
if (NativeCodePage != IntPtr.Zero)
{
return;
}
// Allocate the page, write the native code into it, then set it
// to be executable.
IMemoryMapper mapper = CreateMemoryMapper();
int codeLength = NativeCode.Active.Code.Length;
NativeCodePage = mapper.MapWriteable(codeLength);
Marshal.Copy(NativeCode.Active.Code, 0, NativeCodePage, codeLength);
mapper.SetReadExec(NativeCodePage, codeLength);
}
#endregion
/// <summary>
/// Given a newly allocated Python type object and a managed Type that
/// provides the implementation for the type, connect the type slots of
/// the Python object to the managed methods of the implementing Type.
/// </summary>
internal static void InitializeSlots(IntPtr type, Type impl)
{
// We work from the most-derived class up; make sure to get
// the most-derived slot and not to override it with a base
// class's slot.
var seen = new HashSet<string>();
while (impl != null)
{
MethodInfo[] methods = impl.GetMethods(tbFlags);
foreach (MethodInfo method in methods)
{
string name = method.Name;
if (!(name.StartsWith("tp_") ||
name.StartsWith("nb_") ||
name.StartsWith("sq_") ||
name.StartsWith("mp_") ||
name.StartsWith("bf_")
))
{
continue;
}
if (seen.Contains(name))
{
continue;
}
var thunkInfo = Interop.GetThunk(method);
InitializeSlot(type, thunkInfo.Address, name);
seen.Add(name);
}
impl = impl.BaseType;
}
var native = NativeCode.Active;
// The garbage collection related slots always have to return 1 or 0
// since .NET objects don't take part in Python's gc:
// tp_traverse (returns 0)
// tp_clear (returns 0)
// tp_is_gc (returns 1)
// These have to be defined, though, so by default we fill these with
// static C# functions from this class.
var ret0 = Interop.GetThunk(((Func<IntPtr, int>)Return0).Method).Address;
var ret1 = Interop.GetThunk(((Func<IntPtr, int>)Return1).Method).Address;
if (native != null)
{
// If we want to support domain reload, the C# implementation
// cannot be used as the assembly may get released before
// CPython calls these functions. Instead, for amd64 and x86 we
// load them into a separate code page that is leaked
// intentionally.
InitializeNativeCodePage();
ret1 = NativeCodePage + native.Return1;
ret0 = NativeCodePage + native.Return0;
}
InitializeSlot(type, ret0, "tp_traverse");
InitializeSlot(type, ret0, "tp_clear");
InitializeSlot(type, ret1, "tp_is_gc");
}
static int Return1(IntPtr _) => 1;
static int Return0(IntPtr _) => 0;
/// <summary>
/// Helper for InitializeSlots.
///
/// Initializes one slot to point to a function pointer.
/// The function pointer might be a thunk for C#, or it may be
/// an address in the NativeCodePage.
/// </summary>
/// <param name="type">Type being initialized.</param>
/// <param name="slot">Function pointer.</param>
/// <param name="name">Name of the method.</param>
static void InitializeSlot(IntPtr type, IntPtr slot, string name)
{
Type typeOffset = typeof(TypeOffset);
FieldInfo fi = typeOffset.GetField(name);
var offset = (int)fi.GetValue(typeOffset);
Marshal.WriteIntPtr(type, offset, slot);
}
/// <summary>
/// Given a newly allocated Python type object and a managed Type that
/// implements it, initialize any methods defined by the Type that need
/// to appear in the Python type __dict__ (based on custom attribute).
/// </summary>
private static void InitMethods(IntPtr pytype, Type type)
{
IntPtr dict = Marshal.ReadIntPtr(pytype, TypeOffset.tp_dict);
Type marker = typeof(PythonMethodAttribute);
BindingFlags flags = BindingFlags.Public | BindingFlags.Static;
var addedMethods = new HashSet<string>();
while (type != null)
{
MethodInfo[] methods = type.GetMethods(flags);
foreach (MethodInfo method in methods)
{
if (!addedMethods.Contains(method.Name))
{
object[] attrs = method.GetCustomAttributes(marker, false);
if (attrs.Length > 0)
{
string method_name = method.Name;
var mi = new MethodInfo[1];
mi[0] = method;
MethodObject m = new TypeMethod(type, method_name, mi);
Runtime.PyDict_SetItemString(dict, method_name, m.pyHandle);
addedMethods.Add(method_name);
}
}
}
type = type.BaseType;
}
}
/// <summary>
/// Utility method to copy slots from a given type to another type.
/// </summary>
internal static void CopySlot(IntPtr from, IntPtr to, int offset)
{
IntPtr fp = Marshal.ReadIntPtr(from, offset);
Marshal.WriteIntPtr(to, offset, fp);
}
}
}