Implement PyTypeInfo for PyEllipsis, PyNone, and `PyNotImplemen…

…ted`

newsfragments/3577.added.md

@@ -0,0 +1 @@
+Implement `PyTypeInfo` for `PyEllipsis`, `PyNone` and `PyNotImplemented`.

src/types/ellipsis.rs

@@ -1,4 +1,4 @@
-use crate::{ffi, PyAny, PyDowncastError, PyTryFrom, Python};
+use crate::{ffi, PyAny, PyTypeInfo, Python};
 
 /// Represents the Python `Ellipsis` object.
 #[repr(transparent)]
@@ -15,24 +15,26 @@ impl PyEllipsis {
     }
 }
 
-impl<'v> PyTryFrom<'v> for PyEllipsis {
-    fn try_from<V: Into<&'v PyAny>>(value: V) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        let value: &PyAny = value.into();
-        if unsafe { ffi::Py_Ellipsis() == value.as_ptr() } {
-            return unsafe { Ok(value.downcast_unchecked()) };
-        }
-        Err(PyDowncastError::new(value, "ellipsis"))
+unsafe impl PyTypeInfo for PyEllipsis {
+    const NAME: &'static str = "ellipsis";
+
+    const MODULE: Option<&'static str> = None;
+
+    type AsRefTarget = PyEllipsis;
+
+    fn type_object_raw(_py: Python<'_>) -> *mut ffi::PyTypeObject {
+        unsafe { ffi::Py_TYPE(ffi::Py_Ellipsis()) }
     }
 
-    fn try_from_exact<V: Into<&'v PyAny>>(
-        value: V,
-    ) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        value.into().downcast()
+    #[inline]
+    fn is_type_of(object: &PyAny) -> bool {
+        // ellipsis is not usable as a base type
+        Self::is_exact_type_of(object)
     }
 
-    unsafe fn try_from_unchecked<V: Into<&'v PyAny>>(value: V) -> &'v Self {
-        let ptr = value.into() as *const _ as *const PyEllipsis;
-        &*ptr
+    #[inline]
+    fn is_exact_type_of(object: &PyAny) -> bool {
+        object.is(PyEllipsis::get(object.py()))
     }
 }
 

src/types/none.rs

@@ -1,4 +1,4 @@
-use crate::{ffi, IntoPy, PyAny, PyDowncastError, PyObject, PyTryFrom, Python, ToPyObject};
+use crate::{ffi, IntoPy, PyAny, PyObject, PyTypeInfo, Python, ToPyObject};
 
 /// Represents the Python `None` object.
 #[repr(transparent)]
@@ -15,24 +15,26 @@ impl PyNone {
     }
 }
 
-impl<'v> PyTryFrom<'v> for PyNone {
-    fn try_from<V: Into<&'v PyAny>>(value: V) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        let value: &PyAny = value.into();
-        if value.is_none() {
-            return unsafe { Ok(value.downcast_unchecked()) };
-        }
-        Err(PyDowncastError::new(value, "NoneType"))
+unsafe impl PyTypeInfo for PyNone {
+    const NAME: &'static str = "NoneType";
+
+    const MODULE: Option<&'static str> = None;
+
+    type AsRefTarget = PyNone;
+
+    fn type_object_raw(_py: Python<'_>) -> *mut ffi::PyTypeObject {
+        unsafe { ffi::Py_TYPE(ffi::Py_None()) }
     }
 
-    fn try_from_exact<V: Into<&'v PyAny>>(
-        value: V,
-    ) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        value.into().downcast()
+    #[inline]
+    fn is_type_of(object: &PyAny) -> bool {
+        // NoneType is not usable as a base type
+        Self::is_exact_type_of(object)
     }
 
-    unsafe fn try_from_unchecked<V: Into<&'v PyAny>>(value: V) -> &'v Self {
-        let ptr = value.into() as *const _ as *const PyNone;
-        &*ptr
+    #[inline]
+    fn is_exact_type_of(object: &PyAny) -> bool {
+        object.is_none()
     }
 }
 

src/types/notimplemented.rs

@@ -1,4 +1,6 @@
-use crate::{ffi, PyAny, PyDowncastError, PyTryFrom, Python};
+use crate::{ffi, PyAny, PyTypeInfo, Python};
+
+use super::PyEllipsis;
 
 /// Represents the Python `NotImplemented` object.
 #[repr(transparent)]
@@ -15,24 +17,26 @@ impl PyNotImplemented {
     }
 }
 
-impl<'v> PyTryFrom<'v> for PyNotImplemented {
-    fn try_from<V: Into<&'v PyAny>>(value: V) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        let value: &PyAny = value.into();
-        if unsafe { ffi::Py_NotImplemented() == value.as_ptr() } {
-            return unsafe { Ok(value.downcast_unchecked()) };
-        }
-        Err(PyDowncastError::new(value, "NotImplementedType"))
+unsafe impl PyTypeInfo for PyNotImplemented {
+    const NAME: &'static str = "NotImplementedType";
+
+    const MODULE: Option<&'static str> = None;
+
+    type AsRefTarget = PyNotImplemented;
+
+    fn type_object_raw(_py: Python<'_>) -> *mut ffi::PyTypeObject {
+        unsafe { ffi::Py_TYPE(ffi::Py_None()) }
     }
 
-    fn try_from_exact<V: Into<&'v PyAny>>(
-        value: V,
-    ) -> Result<&'v Self, crate::PyDowncastError<'v>> {
-        value.into().downcast()
+    #[inline]
+    fn is_type_of(object: &PyAny) -> bool {
+        // NoneType is not usable as a base type
+        Self::is_exact_type_of(object)
     }
 
-    unsafe fn try_from_unchecked<V: Into<&'v PyAny>>(value: V) -> &'v Self {
-        let ptr = value.into() as *const _ as *const PyNotImplemented;
-        &*ptr
+    #[inline]
+    fn is_exact_type_of(object: &PyAny) -> bool {
+        object.is(PyEllipsis::get(object.py()))
     }
 }