Proof of concept of using PEP384s PyType_Spec

Author: alex

guide/src/class.md

@@ -205,7 +205,7 @@ or by `self_.into_super()` as `PyRef<Self::BaseClass>`.
 ```rust
 # use pyo3::prelude::*;
 
-#[pyclass]
+#[pyclass(subclass)]
 struct BaseClass {
     val1: usize,
 }
@@ -222,7 +222,7 @@ impl BaseClass {
     }
 }
 
-#[pyclass(extends=BaseClass)]
+#[pyclass(extends=BaseClass, subclass)]
 struct SubClass {
     val2: usize,
 }

src/class/basic.rs

@@ -9,8 +9,9 @@
 //! [typeobj docs](https://docs.python.org/3/c-api/typeobj.html)
 
 use crate::callback::{HashCallbackOutput, IntoPyCallbackOutput};
+use crate::pyclass::maybe_push_slot;
 use crate::{exceptions, ffi, FromPyObject, PyAny, PyCell, PyClass, PyErr, PyObject, PyResult};
-use std::os::raw::c_int;
+use std::os::raw::{c_int, c_void};
 
 /// Operators for the __richcmp__ method
 #[derive(Debug)]
@@ -147,13 +148,38 @@ pub struct PyObjectMethods {
 
 #[doc(hidden)]
 impl PyObjectMethods {
-    pub(crate) fn update_typeobj(&self, type_object: &mut ffi::PyTypeObject) {
-        type_object.tp_str = self.tp_str;
-        type_object.tp_repr = self.tp_repr;
-        type_object.tp_hash = self.tp_hash;
-        type_object.tp_getattro = self.tp_getattro;
-        type_object.tp_richcompare = self.tp_richcompare;
-        type_object.tp_setattro = self.tp_setattro;
+    pub(crate) fn update_slots(&self, slots: &mut Vec<ffi::PyType_Slot>) {
+        maybe_push_slot(slots, ffi::Py_tp_str, self.tp_str.map(|v| v as *mut c_void));
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_repr,
+            self.tp_repr.map(|v| v as *mut c_void),
+        );
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_hash,
+            self.tp_hash.map(|v| v as *mut c_void),
+        );
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_getattro,
+            self.tp_getattro.map(|v| v as *mut c_void),
+        );
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_richcompare,
+            self.tp_richcompare.map(|v| v as *mut c_void),
+        );
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_setattro,
+            self.tp_setattro.map(|v| v as *mut c_void),
+        );
+        maybe_push_slot(
+            slots,
+            ffi::Py_nb_bool,
+            self.nb_bool.map(|v| v as *mut c_void),
+        );
     }
     // Set functions used by `#[pyproto]`.
     pub fn set_str<T>(&mut self)

src/class/descr.rs

@@ -6,9 +6,10 @@
 //! https://docs.python.org/3/reference/datamodel.html#implementing-descriptors)
 
 use crate::callback::IntoPyCallbackOutput;
+use crate::pyclass::maybe_push_slot;
 use crate::types::PyAny;
 use crate::{ffi, FromPyObject, PyClass, PyObject};
-use std::os::raw::c_int;
+use std::os::raw::{c_int, c_void};
 
 /// Descriptor interface
 #[allow(unused_variables)]
@@ -79,9 +80,17 @@ pub struct PyDescrMethods {
 
 #[doc(hidden)]
 impl PyDescrMethods {
-    pub(crate) fn update_typeobj(&self, type_object: &mut ffi::PyTypeObject) {
-        type_object.tp_descr_get = self.tp_descr_get;
-        type_object.tp_descr_set = self.tp_descr_set;
+    pub(crate) fn update_slots(&self, slots: &mut Vec<ffi::PyType_Slot>) {
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_descr_get,
+            self.tp_descr_get.map(|v| v as *mut c_void),
+        );
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_descr_set,
+            self.tp_descr_set.map(|v| v as *mut c_void),
+        );
     }
     pub fn set_descr_get<T>(&mut self)
     where

src/class/gc.rs

@@ -3,6 +3,7 @@
 //! Python GC support
 //!
 
+use crate::pyclass::maybe_push_slot;
 use crate::{ffi, AsPyPointer, PyCell, PyClass, Python};
 use std::os::raw::{c_int, c_void};
 
@@ -27,9 +28,17 @@ pub struct PyGCMethods {
 
 #[doc(hidden)]
 impl PyGCMethods {
-    pub(crate) fn update_typeobj(&self, type_object: &mut ffi::PyTypeObject) {
-        type_object.tp_traverse = self.tp_traverse;
-        type_object.tp_clear = self.tp_clear;
+    pub(crate) fn update_slots(&self, slots: &mut Vec<ffi::PyType_Slot>) {
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_traverse,
+            self.tp_traverse.map(|v| v as *mut c_void),
+        );
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_clear,
+            self.tp_clear.map(|v| v as *mut c_void),
+        );
     }
 
     pub fn set_traverse<T>(&mut self)

src/class/iter.rs

@@ -5,7 +5,9 @@
 use crate::callback::IntoPyCallbackOutput;
 use crate::derive_utils::TryFromPyCell;
 use crate::err::PyResult;
+use crate::pyclass::maybe_push_slot;
 use crate::{ffi, IntoPy, IntoPyPointer, PyClass, PyObject, Python};
+use std::os::raw::c_void;
 
 /// Python Iterator Interface.
 ///
@@ -79,9 +81,17 @@ pub struct PyIterMethods {
 
 #[doc(hidden)]
 impl PyIterMethods {
-    pub(crate) fn update_typeobj(&self, type_object: &mut ffi::PyTypeObject) {
-        type_object.tp_iter = self.tp_iter;
-        type_object.tp_iternext = self.tp_iternext;
+    pub(crate) fn update_slots(&self, slots: &mut Vec<ffi::PyType_Slot>) {
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_iter,
+            self.tp_iter.map(|v| v as *mut c_void),
+        );
+        maybe_push_slot(
+            slots,
+            ffi::Py_tp_iternext,
+            self.tp_iternext.map(|v| v as *mut c_void),
+        );
     }
     pub fn set_iter<T>(&mut self)
     where

src/class/number.rs

@@ -581,11 +581,6 @@ pub trait PyNumberIndexProtocol<'p>: PyNumberProtocol<'p> {
 
 #[doc(hidden)]
 impl ffi::PyNumberMethods {
-    pub(crate) fn from_nb_bool(nb_bool: ffi::inquiry) -> *mut Self {
-        let mut nm = ffi::PyNumberMethods_INIT;
-        nm.nb_bool = Some(nb_bool);
-        Box::into_raw(Box::new(nm))
-    }
     pub fn set_add_radd<T>(&mut self)
     where
         T: for<'p> PyNumberAddProtocol<'p> + for<'p> PyNumberRAddProtocol<'p>,

src/pycell.rs

@@ -455,7 +455,7 @@ impl<T: PyClass + fmt::Debug> fmt::Debug for PyCell<T> {
 /// - You want to get super class.
 /// ```
 /// # use pyo3::prelude::*;
-/// #[pyclass]
+/// #[pyclass(subclass)]
 /// struct Parent {
 ///     basename: &'static str,
 /// }
@@ -516,11 +516,11 @@ where
     /// # Examples
     /// ```
     /// # use pyo3::prelude::*;
-    /// #[pyclass]
+    /// #[pyclass(subclass)]
     /// struct Base1 {
     ///     name1: &'static str,
     /// }
-    /// #[pyclass(extends=Base1)]
+    /// #[pyclass(extends=Base1, subclass)]
     /// struct Base2 {
     ///     name2: &'static str,
     ///  }