pyo3/types/
none.rs

1use crate::ffi_ptr_ext::FfiPtrExt;
2use crate::{ffi, types::any::PyAnyMethods, Borrowed, Bound, PyAny, PyTypeInfo, Python};
3
4/// Represents the Python `None` object.
5///
6/// Values of this type are accessed via PyO3's smart pointers, e.g. as
7/// [`Py<PyNone>`][crate::Py] or [`Bound<'py, PyNone>`][Bound].
8#[repr(transparent)]
9pub struct PyNone(PyAny);
10
11pyobject_native_type_named!(PyNone);
12
13impl PyNone {
14    /// Returns the `None` object.
15    #[inline]
16    pub fn get(py: Python<'_>) -> Borrowed<'_, '_, PyNone> {
17        unsafe { ffi::Py_None().assume_borrowed(py).downcast_unchecked() }
18    }
19}
20
21unsafe impl PyTypeInfo for PyNone {
22    const NAME: &'static str = "NoneType";
23
24    const MODULE: Option<&'static str> = None;
25
26    fn type_object_raw(_py: Python<'_>) -> *mut ffi::PyTypeObject {
27        unsafe { ffi::Py_TYPE(ffi::Py_None()) }
28    }
29
30    #[inline]
31    fn is_type_of(object: &Bound<'_, PyAny>) -> bool {
32        // NoneType is not usable as a base type
33        Self::is_exact_type_of(object)
34    }
35
36    #[inline]
37    fn is_exact_type_of(object: &Bound<'_, PyAny>) -> bool {
38        object.is(&**Self::get(object.py()))
39    }
40}
41
42#[cfg(test)]
43mod tests {
44    use crate::types::any::PyAnyMethods;
45    use crate::types::{PyDict, PyNone};
46    use crate::{PyTypeInfo, Python};
47
48    #[test]
49    fn test_none_is_itself() {
50        Python::with_gil(|py| {
51            assert!(PyNone::get(py).is_instance_of::<PyNone>());
52            assert!(PyNone::get(py).is_exact_instance_of::<PyNone>());
53        })
54    }
55
56    #[test]
57    fn test_none_type_object_consistent() {
58        Python::with_gil(|py| {
59            assert!(PyNone::get(py).get_type().is(PyNone::type_object(py)));
60        })
61    }
62
63    #[test]
64    fn test_none_is_none() {
65        Python::with_gil(|py| {
66            assert!(PyNone::get(py).downcast::<PyNone>().unwrap().is_none());
67        })
68    }
69
70    #[test]
71    fn test_dict_is_not_none() {
72        Python::with_gil(|py| {
73            assert!(PyDict::new(py).downcast::<PyNone>().is_err());
74        })
75    }
76}
pyo3/types/none.rs

pyo3/types/
none.rs
