Add IntoPyObject & FromPyObject for Arc<T>

Author: bschoenmaeckers

newsfragments/4987.added.md

@@ -0,0 +1 @@
+Add `IntoPyObject` & `FromPyObject` for `Arc<T>`

src/conversions/std/mod.rs

@@ -9,5 +9,6 @@ mod path;
 mod set;
 mod slice;
 mod string;
+mod sync;
 mod time;
 mod vec;

src/conversions/std/sync.rs

@@ -0,0 +1,85 @@
+#[cfg(feature = "experimental-inspect")]
+use crate::inspect::types::TypeInfo;
+use crate::types::PyAnyMethods;
+use crate::{Bound, BoundObject, FromPyObject, IntoPyObject, PyAny, PyErr, PyResult, Python};
+use std::sync::Arc;
+
+// TODO find a better way (without the extra type parameters) to name the associated types in the trait.
+impl<'py, A, T, O, E> IntoPyObject<'py> for Arc<A>
+where
+    for<'a> &'a A: IntoPyObject<'py, Target = T, Output = O, Error = E>,
+    O: BoundObject<'py, T>,
+    E: Into<PyErr>,
+{
+    type Target = T;
+    type Output = O;
+    type Error = E;
+
+    #[inline]
+    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
+        (&*self).into_pyobject(py)
+    }
+
+    #[cfg(feature = "experimental-inspect")]
+    fn type_output() -> TypeInfo {
+        <&A as IntoPyObject<'py>>::type_output()
+    }
+}
+
+impl<'a, 'py, T> IntoPyObject<'py> for &'a Arc<T>
+where
+    &'a T: IntoPyObject<'py>,
+{
+    type Target = <&'a T as IntoPyObject<'py>>::Target;
+    type Output = <&'a T as IntoPyObject<'py>>::Output;
+    type Error = <&'a T as IntoPyObject<'py>>::Error;
+
+    #[inline]
+    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
+        (&**self).into_pyobject(py)
+    }
+
+    #[cfg(feature = "experimental-inspect")]
+    fn type_output() -> TypeInfo {
+        <&'a T as IntoPyObject<'py>>::type_output()
+    }
+}
+
+impl<'py, T> FromPyObject<'py> for Arc<T>
+where
+    T: FromPyObject<'py>,
+{
+    fn extract_bound(ob: &Bound<'py, PyAny>) -> PyResult<Self> {
+        ob.extract::<T>().map(Arc::new)
+    }
+
+    #[cfg(feature = "experimental-inspect")]
+    fn type_input() -> TypeInfo {
+        T::type_input()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::types::PyInt;
+    use crate::Python;
+
+    #[test]
+    fn test_arc_into_pyobject() {
+        macro_rules! test_roundtrip {
+            ($arc:expr) => {
+                Python::with_gil(|py| {
+                    let arc = $arc;
+                    let obj: Bound<'_, PyInt> = arc.into_pyobject(py).unwrap();
+                    assert_eq!(obj.extract::<i32>().unwrap(), 42);
+                    let roundtrip = obj.extract::<Arc<i32>>().unwrap();
+                    assert_eq!(&42, roundtrip.as_ref());
+                });
+            };
+        }
+
+        test_roundtrip!(Arc::new(42));
+        test_roundtrip!(&Arc::new(42));
+    }
+}