pyo3/impl_/
wrap.rs

1use std::{convert::Infallible, marker::PhantomData, ops::Deref};
2
3use crate::{ffi, types::PyNone, Bound, IntoPyObject, IntoPyObjectExt, PyObject, PyResult, Python};
4
5/// Used to wrap values in `Option<T>` for default arguments.
6pub trait SomeWrap<T> {
7    fn wrap(self) -> Option<T>;
8}
9
10impl<T> SomeWrap<T> for T {
11    fn wrap(self) -> Option<T> {
12        Some(self)
13    }
14}
15
16impl<T> SomeWrap<T> for Option<T> {
17    fn wrap(self) -> Self {
18        self
19    }
20}
21
22// Hierarchy of conversions used in the `IntoPy` implementation
23pub struct Converter<T>(EmptyTupleConverter<T>);
24pub struct EmptyTupleConverter<T>(IntoPyObjectConverter<T>);
25pub struct IntoPyObjectConverter<T>(IntoPyConverter<T>);
26pub struct IntoPyConverter<T>(UnknownReturnResultType<T>);
27pub struct UnknownReturnResultType<T>(UnknownReturnType<T>);
28pub struct UnknownReturnType<T>(PhantomData<T>);
29
30pub fn converter<T>(_: &T) -> Converter<T> {
31    Converter(EmptyTupleConverter(IntoPyObjectConverter(IntoPyConverter(
32        UnknownReturnResultType(UnknownReturnType(PhantomData)),
33    ))))
34}
35
36impl<T> Deref for Converter<T> {
37    type Target = EmptyTupleConverter<T>;
38    fn deref(&self) -> &Self::Target {
39        &self.0
40    }
41}
42
43impl<T> Deref for EmptyTupleConverter<T> {
44    type Target = IntoPyObjectConverter<T>;
45    fn deref(&self) -> &Self::Target {
46        &self.0
47    }
48}
49
50impl<T> Deref for IntoPyObjectConverter<T> {
51    type Target = IntoPyConverter<T>;
52    fn deref(&self) -> &Self::Target {
53        &self.0
54    }
55}
56
57impl<T> Deref for IntoPyConverter<T> {
58    type Target = UnknownReturnResultType<T>;
59    fn deref(&self) -> &Self::Target {
60        &self.0
61    }
62}
63
64impl<T> Deref for UnknownReturnResultType<T> {
65    type Target = UnknownReturnType<T>;
66    fn deref(&self) -> &Self::Target {
67        &self.0
68    }
69}
70
71impl EmptyTupleConverter<PyResult<()>> {
72    #[inline]
73    pub fn map_into_ptr(&self, py: Python<'_>, obj: PyResult<()>) -> PyResult<*mut ffi::PyObject> {
74        obj.map(|_| PyNone::get(py).to_owned().into_ptr())
75    }
76}
77
78impl<'py, T: IntoPyObject<'py>> IntoPyObjectConverter<T> {
79    #[inline]
80    pub fn wrap(&self, obj: T) -> Result<T, Infallible> {
81        Ok(obj)
82    }
83}
84
85impl<'py, T: IntoPyObject<'py>, E> IntoPyObjectConverter<Result<T, E>> {
86    #[inline]
87    pub fn wrap(&self, obj: Result<T, E>) -> Result<T, E> {
88        obj
89    }
90
91    #[inline]
92    pub fn map_into_pyobject(&self, py: Python<'py>, obj: PyResult<T>) -> PyResult<PyObject>
93    where
94        T: IntoPyObject<'py>,
95    {
96        obj.and_then(|obj| obj.into_py_any(py))
97    }
98
99    #[inline]
100    pub fn map_into_ptr(&self, py: Python<'py>, obj: PyResult<T>) -> PyResult<*mut ffi::PyObject>
101    where
102        T: IntoPyObject<'py>,
103    {
104        obj.and_then(|obj| obj.into_bound_py_any(py))
105            .map(Bound::into_ptr)
106    }
107}
108
109impl<T, E> UnknownReturnResultType<Result<T, E>> {
110    #[inline]
111    pub fn wrap<'py>(&self, _: Result<T, E>) -> Result<T, E>
112    where
113        T: IntoPyObject<'py>,
114    {
115        unreachable!("should be handled by IntoPyObjectConverter")
116    }
117}
118
119impl<T> UnknownReturnType<T> {
120    #[inline]
121    pub fn wrap<'py>(&self, _: T) -> T
122    where
123        T: IntoPyObject<'py>,
124    {
125        unreachable!("should be handled by IntoPyObjectConverter")
126    }
127
128    #[inline]
129    pub fn map_into_pyobject<'py>(&self, _: Python<'py>, _: PyResult<T>) -> PyResult<PyObject>
130    where
131        T: IntoPyObject<'py>,
132    {
133        unreachable!("should be handled by IntoPyObjectConverter")
134    }
135
136    #[inline]
137    pub fn map_into_ptr<'py>(&self, _: Python<'py>, _: PyResult<T>) -> PyResult<*mut ffi::PyObject>
138    where
139        T: IntoPyObject<'py>,
140    {
141        unreachable!("should be handled by IntoPyObjectConverter")
142    }
143}
144
145#[cfg(test)]
146mod tests {
147    use super::*;
148
149    #[test]
150    fn wrap_option() {
151        let a: Option<u8> = SomeWrap::wrap(42);
152        assert_eq!(a, Some(42));
153
154        let b: Option<u8> = SomeWrap::wrap(None);
155        assert_eq!(b, None);
156    }
157}
pyo3/impl_/wrap.rs

pyo3/impl_/
wrap.rs
