Add PyTzInfoAccess

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Add an experimental `generate-abi3-import-lib` feature to auto-generate `python3.dll` import libraries for Windows. [#2282](https://github.com/PyO3/pyo3/pull/2282)
 - Add FFI definitions for `PyDateTime_BaseTime` and `PyDateTime_BaseDateTime`. [#2294](https://github.com/PyO3/pyo3/pull/2294)
+- Added `PyTzInfoAccess` for safe access to time zone information. [#2263](https://github.com/PyO3/pyo3/pull/2263)
 
 ### Changed
 

pytests/src/datetime.rs

@@ -3,7 +3,7 @@
 use pyo3::prelude::*;
 use pyo3::types::{
     PyDate, PyDateAccess, PyDateTime, PyDelta, PyDeltaAccess, PyTime, PyTimeAccess, PyTuple,
-    PyTzInfo,
+    PyTzInfo, PyTzInfoAccess,
 };
 
 #[pyfunction]
@@ -179,6 +179,16 @@ fn datetime_from_timestamp<'p>(
     PyDateTime::from_timestamp(py, ts, tz)
 }
 
+#[pyfunction]
+fn get_datetime_tzinfo(dt: &PyDateTime) -> Option<&PyTzInfo> {
+    dt.get_tzinfo()
+}
+
+#[pyfunction]
+fn get_time_tzinfo(dt: &PyTime) -> Option<&PyTzInfo> {
+    dt.get_tzinfo()
+}
+
 #[pyclass(extends=PyTzInfo)]
 pub struct TzClass {}
 
@@ -214,6 +224,8 @@ pub fn datetime(_py: Python<'_>, m: &PyModule) -> PyResult<()> {
     m.add_function(wrap_pyfunction!(make_datetime, m)?)?;
     m.add_function(wrap_pyfunction!(get_datetime_tuple, m)?)?;
     m.add_function(wrap_pyfunction!(datetime_from_timestamp, m)?)?;
+    m.add_function(wrap_pyfunction!(get_datetime_tzinfo, m)?)?;
+    m.add_function(wrap_pyfunction!(get_time_tzinfo, m)?)?;
 
     // Functions not supported by PyPy
     #[cfg(not(PyPy))]

pytests/tests/test_datetime.py

@@ -114,6 +114,7 @@ def test_time(args, kwargs):
 
     assert act == exp
     assert act.tzinfo is exp.tzinfo
+    assert rdt.get_time_tzinfo(act) == exp.tzinfo
 
 
 @given(t=st.times())
@@ -194,6 +195,7 @@ def test_datetime(args, kwargs):
 
     assert act == exp
     assert act.tzinfo is exp.tzinfo
+    assert rdt.get_datetime_tzinfo(act) == exp.tzinfo
 
 
 @given(dt=st.datetimes())

src/types/datetime.rs

@@ -4,9 +4,8 @@
 //! documentation](https://docs.python.org/3/library/datetime.html)
 
 use crate::err::PyResult;
-use crate::ffi;
 use crate::ffi::{
-    PyDateTime_CAPI, PyDateTime_FromTimestamp, PyDateTime_IMPORT, PyDate_FromTimestamp,
+    self, PyDateTime_CAPI, PyDateTime_FromTimestamp, PyDateTime_IMPORT, PyDate_FromTimestamp,
 };
 #[cfg(not(PyPy))]
 use crate::ffi::{PyDateTime_DATE_GET_FOLD, PyDateTime_TIME_GET_FOLD};
@@ -22,6 +21,7 @@ use crate::ffi::{
     PyDateTime_TIME_GET_HOUR, PyDateTime_TIME_GET_MICROSECOND, PyDateTime_TIME_GET_MINUTE,
     PyDateTime_TIME_GET_SECOND,
 };
+use crate::instance::PyNativeType;
 use crate::types::PyTuple;
 use crate::{AsPyPointer, PyAny, PyObject, Python, ToPyObject};
 use std::os::raw::c_int;
@@ -160,6 +160,16 @@ pub trait PyTimeAccess {
     fn get_fold(&self) -> bool;
 }
 
+/// Trait for accessing the components of a struct containing a tzinfo.
+pub trait PyTzInfoAccess {
+    /// Returns the tzinfo (which may be None).
+    ///
+    /// Implementations should conform to the upstream documentation:
+    /// <https://docs.python.org/3/c-api/datetime.html#c.PyDateTime_DATE_GET_TZINFO>
+    /// <https://docs.python.org/3/c-api/datetime.html#c.PyDateTime_TIME_GET_TZINFO>
+    fn get_tzinfo(&self) -> Option<&PyTzInfo>;
+}
+
 /// Bindings around `datetime.date`
 #[repr(transparent)]
 pub struct PyDate(PyAny);
@@ -354,6 +364,19 @@ impl PyTimeAccess for PyDateTime {
     }
 }
 
+impl PyTzInfoAccess for PyDateTime {
+    fn get_tzinfo(&self) -> Option<&PyTzInfo> {
+        let ptr = self.as_ptr() as *mut ffi::PyDateTime_DateTime;
+        unsafe {
+            if (*ptr).hastzinfo != 0 {
+                Some(self.py().from_borrowed_ptr((*ptr).tzinfo))
+            } else {
+                None
+            }
+        }
+    }
+}
+
 /// Bindings for `datetime.time`
 #[repr(transparent)]
 pub struct PyTime(PyAny);
@@ -439,6 +462,19 @@ impl PyTimeAccess for PyTime {
     }
 }
 
+impl PyTzInfoAccess for PyTime {
+    fn get_tzinfo(&self) -> Option<&PyTzInfo> {
+        let ptr = self.as_ptr() as *mut ffi::PyDateTime_Time;
+        unsafe {
+            if (*ptr).hastzinfo != 0 {
+                Some(self.py().from_borrowed_ptr((*ptr).tzinfo))
+            } else {
+                None
+            }
+        }
+    }
+}
+
 /// Bindings for `datetime.tzinfo`
 ///
 /// This is an abstract base class and should not be constructed directly.
@@ -524,4 +560,33 @@ mod tests {
             assert!(b.unwrap().get_fold());
         });
     }
+
+    #[cfg(not(PyPy))]
+    #[test]
+    fn test_get_tzinfo() {
+        crate::Python::with_gil(|py| {
+            use crate::conversion::ToPyObject;
+            use crate::types::{PyDateTime, PyTime, PyTzInfoAccess};
+
+            let datetime = py.import("datetime").map_err(|e| e.print(py)).unwrap();
+            let timezone = datetime.getattr("timezone").unwrap();
+            let utc = timezone.getattr("utc").unwrap().to_object(py);
+
+            let dt = PyDateTime::new(py, 2018, 1, 1, 0, 0, 0, 0, Some(&utc)).unwrap();
+
+            assert!(dt.get_tzinfo().unwrap().eq(&utc).unwrap());
+
+            let dt = PyDateTime::new(py, 2018, 1, 1, 0, 0, 0, 0, None).unwrap();
+
+            assert!(dt.get_tzinfo().is_none());
+
+            let t = PyTime::new(py, 0, 0, 0, 0, Some(&utc)).unwrap();
+
+            assert!(t.get_tzinfo().unwrap().eq(&utc).unwrap());
+
+            let t = PyTime::new(py, 0, 0, 0, 0, None).unwrap();
+
+            assert!(t.get_tzinfo().is_none());
+        });
+    }
 }

src/types/mod.rs

@@ -11,6 +11,7 @@ pub use self::complex::PyComplex;
 #[cfg(not(Py_LIMITED_API))]
 pub use self::datetime::{
     PyDate, PyDateAccess, PyDateTime, PyDelta, PyDeltaAccess, PyTime, PyTimeAccess, PyTzInfo,
+    PyTzInfoAccess,
 };
 pub use self::dict::{IntoPyDict, PyDict};
 pub use self::floatob::PyFloat;