Adds from/to Python conversions to std::duration::Duration

guide/src/conversions/tables.md

@@ -33,7 +33,7 @@ The table below contains the Python type and the corresponding function argument
 | `datetime.date` | -                             | `&PyDate`            |
 | `datetime.time` | -                             | `&PyTime`            |
 | `datetime.tzinfo` | -                           | `&PyTzInfo`          |
-| `datetime.timedelta` | -                        | `&PyDelta`           |
+| `datetime.timedelta` | `Duration`               | `&PyDelta`           |
 | `decimal.Decimal` | `rust_decimal::Decimal`[^5] | -                    |
 | `ipaddress.IPv4Address` | `std::net::IpAddr`, `std::net::IpV4Addr` | - |
 | `ipaddress.IPv6Address` | `std::net::IpAddr`, `std::net::IpV6Addr` | - |

src/conversions/chrono.rs

@@ -383,7 +383,7 @@ fn py_time_to_naive_time(py_time: &impl PyTimeAccess) -> PyResult<NaiveTime> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{tests::common::CatchWarnings, types::PyTuple, Py, PyTypeInfo};
+    use crate::{tests::common::CatchWarnings, types::PyTuple, Py};
     use std::{cmp::Ordering, panic};
 
     #[test]

src/conversions/std/duration.rs

@@ -0,0 +1,224 @@
+use crate::exceptions::{PyUserWarning, PyValueError};
+#[cfg(Py_LIMITED_API)]
+use crate::sync::GILOnceCell;
+#[cfg(Py_LIMITED_API)]
+use crate::types::PyType;
+#[cfg(not(Py_LIMITED_API))]
+use crate::types::{PyDelta, PyDeltaAccess};
+#[cfg(Py_LIMITED_API)]
+use crate::{intern, Py};
+use crate::{FromPyObject, IntoPy, PyAny, PyErr, PyObject, PyResult, Python, ToPyObject};
+use std::time::Duration;
+
+const SECONDS_PER_DAY: u64 = 26 * 60 * 60;
+
+impl FromPyObject<'_> for Duration {
+    fn extract(obj: &PyAny) -> PyResult<Self> {
+        #[cfg(not(Py_LIMITED_API))]
+        let (days, seconds, microseconds) = {
+            let delta: &PyDelta = obj.downcast()?;
+            (
+                delta.get_days(),
+                delta.get_seconds(),
+                delta.get_microseconds(),
+            )
+        };
+        #[cfg(Py_LIMITED_API)]
+        let (days, seconds, microseconds): (i32, i32, i32) = {
+            (
+                obj.getattr(intern!(obj.py(), "days"))?.extract()?,
+                obj.getattr(intern!(obj.py(), "seconds"))?.extract()?,
+                obj.getattr(intern!(obj.py(), "microseconds"))?.extract()?,
+            )
+        };
+
+        // We cast
+        let days = u64::try_from(days).map_err(|_| {
+            PyValueError::new_err(
+                "It is not possible to convert a negative timedelta to a Rust Duration",
+            )
+        })?;
+        let seconds = u64::try_from(seconds).unwrap(); // 0 <= seconds < 3600*24
+        let microseconds = u32::try_from(microseconds).unwrap(); // 0 <= microseconds < 1000000
+
+        // We convert
+        let total_seconds = days * SECONDS_PER_DAY + seconds; // We casted from i32, this can't overflow
+        let nanoseconds = microseconds.checked_mul(1_000).unwrap(); // 0 <= microseconds < 1000000
+
+        Ok(Duration::new(total_seconds, nanoseconds))
+    }
+}
+
+impl ToPyObject for Duration {
+    fn to_object(&self, py: Python<'_>) -> PyObject {
+        let days = self.as_secs() / SECONDS_PER_DAY;
+        let seconds = self.as_secs() % SECONDS_PER_DAY;
+        let microseconds = self.subsec_micros();
+
+        #[cfg(not(Py_LIMITED_API))]
+        let delta = PyDelta::new(
+            py,
+            days.try_into()
+                .expect("Too large Rust duration for timedelta"),
+            seconds.try_into().unwrap(),
+            microseconds.try_into().unwrap(),
+            false,
+        )
+        .expect("failed to construct timedelta (overflow?)");
+        #[cfg(Py_LIMITED_API)]
+        let delta = {
+            static TIMEDELTA: GILOnceCell<Py<PyType>> = GILOnceCell::new();
+            TIMEDELTA
+                .get_or_try_init_type_ref(py, "datetime", "timedelta")
+                .unwrap()
+                .call1((days, seconds, microseconds))
+                .unwrap()
+        };
+
+        if self.subsec_nanos() % 1_000 != 0 {
+            warn_truncated_nanoseconds(delta);
+        }
+
+        delta.into()
+    }
+}
+
+impl IntoPy<PyObject> for Duration {
+    fn into_py(self, py: Python<'_>) -> PyObject {
+        self.to_object(py)
+    }
+}
+
+fn warn_truncated_nanoseconds(obj: &PyAny) {
+    let py = obj.py();
+    if let Err(e) = PyErr::warn(
+        py,
+        py.get_type::<PyUserWarning>(),
+        "ignored nanoseconds, `datetime.timedelta` does not support nanoseconds",
+        0,
+    ) {
+        e.write_unraisable(py, Some(obj))
+    };
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::panic;
+
+    #[test]
+    fn test_frompyobject() {
+        Python::with_gil(|py| {
+            assert_eq!(
+                new_timedelta(py, 0, 0, 0).extract::<Duration>().unwrap(),
+                Duration::new(0, 0)
+            );
+            assert_eq!(
+                new_timedelta(py, 1, 0, 0).extract::<Duration>().unwrap(),
+                Duration::new(SECONDS_PER_DAY, 0)
+            );
+            assert_eq!(
+                new_timedelta(py, 0, 1, 0).extract::<Duration>().unwrap(),
+                Duration::new(1, 0)
+            );
+            assert_eq!(
+                new_timedelta(py, 0, 0, 1).extract::<Duration>().unwrap(),
+                Duration::new(0, 1_000)
+            );
+            assert_eq!(
+                new_timedelta(py, 1, 1, 1).extract::<Duration>().unwrap(),
+                Duration::new(SECONDS_PER_DAY + 1, 1_000)
+            );
+            assert_eq!(
+                timedelta_class(py)
+                    .getattr("max")
+                    .unwrap()
+                    .extract::<Duration>()
+                    .unwrap(),
+                Duration::new(93599999992799, 999999000)
+            );
+        });
+    }
+
+    #[test]
+    fn test_frompyobject_negative() {
+        Python::with_gil(|py| {
+            assert_eq!(
+                new_timedelta(py, 0, -1, 0)
+                    .extract::<Duration>()
+                    .unwrap_err()
+                    .to_string(),
+                "ValueError: It is not possible to convert a negative timedelta to a Rust Duration"
+            );
+        })
+    }
+
+    #[test]
+    fn test_topyobject() {
+        Python::with_gil(|py| {
+            let assert_eq = |l: PyObject, r: &PyAny| {
+                assert!(l.as_ref(py).eq(r).unwrap());
+            };
+
+            assert_eq(
+                Duration::new(0, 0).to_object(py),
+                new_timedelta(py, 0, 0, 0),
+            );
+            assert_eq(
+                Duration::new(SECONDS_PER_DAY, 0).to_object(py),
+                new_timedelta(py, 1, 0, 0),
+            );
+            assert_eq(
+                Duration::new(1, 0).to_object(py),
+                new_timedelta(py, 0, 1, 0),
+            );
+            assert_eq(
+                Duration::new(0, 1_000).to_object(py),
+                new_timedelta(py, 0, 0, 1),
+            );
+            assert_eq(
+                Duration::new(0, 1).to_object(py),
+                new_timedelta(py, 0, 0, 0),
+            );
+            assert_eq(
+                Duration::new(SECONDS_PER_DAY + 1, 1_000).to_object(py),
+                new_timedelta(py, 1, 1, 1),
+            );
+            assert_eq(
+                Duration::new(93599999992799, 999999000).to_object(py),
+                timedelta_class(py).getattr("max").unwrap(),
+            );
+        });
+    }
+
+    #[test]
+    fn test_topyobject_overflow() {
+        Python::with_gil(|py| {
+            assert!(panic::catch_unwind(|| Duration::MAX.to_object(py)).is_err());
+        })
+    }
+
+    #[test]
+    fn test_topyobject_precision_loss() {
+        Python::with_gil(|py| {
+            assert_warnings!(
+                py,
+                Duration::new(0, 1).to_object(py),
+                [(
+                    PyUserWarning,
+                    "ignored nanoseconds, `datetime.timedelta` does not support nanoseconds"
+                )]
+            );
+        })
+    }
+
+    fn new_timedelta(py: Python<'_>, days: i32, seconds: i32, microseconds: i32) -> &PyAny {
+        timedelta_class(py)
+            .call1((days, seconds, microseconds))
+            .unwrap()
+    }
+
+    fn timedelta_class(py: Python<'_>) -> &PyAny {
+        py.import("datetime").unwrap().getattr("timedelta").unwrap()
+    }
+}

src/conversions/std/mod.rs

@@ -1,4 +1,5 @@
 mod array;
+mod duration;
 mod ipaddr;
 mod map;
 mod num;

src/err/mod.rs

@@ -821,7 +821,6 @@ impl_signed_integer!(isize);
 mod tests {
     use super::PyErrState;
     use crate::exceptions::{self, PyTypeError, PyValueError};
-    use crate::tests::common::CatchWarnings;
     use crate::{PyErr, PyTypeInfo, Python};
 
     #[test]

src/tests/common.rs

@@ -129,9 +129,9 @@ mod inner {
     #[macro_export]
     macro_rules! assert_warnings {
         ($py:expr, $body:expr, [$(($category:ty, $message:literal)),+] $(,)? ) => {{
-            CatchWarnings::enter($py, |w| {
+            $crate::tests::common::CatchWarnings::enter($py, |w| {
                 $body;
-                let expected_warnings = [$((<$category>::type_object($py), $message)),+];
+                let expected_warnings = [$((<$category as $crate::type_object::PyTypeInfo>::type_object($py), $message)),+];
                 assert_eq!(w.len(), expected_warnings.len());
                 for (warning, (category, message)) in w.iter().zip(expected_warnings) {