Add from-Python conversions from datetime.time to `absl::Duration`, `absl::Time`

For compatibility with Google-internal Clif_PyObjAs/From implementations.

This is to support the PyCLIF-pybind11 integration.

PiperOrigin-RevId: 526718225

pybind11_abseil/absl_casters.h

@@ -34,6 +34,9 @@
 #include <pybind11/pybind11.h>
 #include <pybind11/stl.h>
 
+// Must NOT appear before at least one pybind11 include.
+#include <datetime.h>  // Python datetime builtin.
+
 #include <cmath>
 #include <cstdint>
 #include <tuple>
@@ -107,6 +110,14 @@ struct type_caster<absl::TimeZone> {
   }
 };
 
+namespace internal {
+inline void EnsurePyDateTime_IMPORT() {
+  if (PyDateTimeAPI == nullptr) {
+    PyDateTime_IMPORT;
+  }
+}
+}  // namespace internal
+
 // Convert between absl::Duration and python datetime.timedelta.
 template <>
 struct type_caster<absl::Duration> {
@@ -117,16 +128,26 @@ struct type_caster<absl::Duration> {
 
   // Conversion part 1 (Python->C++)
   bool load(handle src, bool convert) {
+    // As early as possible to avoid mid-process surprises.
+    internal::EnsurePyDateTime_IMPORT();
     if (!convert) {
       return false;
     }
     if (PyFloat_Check(src.ptr())) {
       value = absl::Seconds(src.cast<double>());
       return true;
-    } else if (PyLong_Check(src.ptr())) {
+    }
+    if (PyLong_Check(src.ptr())) {
       value = absl::Seconds(src.cast<int64_t>());
       return true;
-    } else {
+    }
+    if (PyTime_Check(src.ptr())) {
+      value = absl::Hours(PyDateTime_TIME_GET_HOUR(src.ptr())) +
+              absl::Minutes(PyDateTime_TIME_GET_MINUTE(src.ptr())) +
+              absl::Seconds(PyDateTime_TIME_GET_SECOND(src.ptr())) +
+              absl::Microseconds(PyDateTime_TIME_GET_MICROSECOND(src.ptr()));
+      return true;
+    }
     // Ensure that absl::Duration is converted from a Python
     // datetime.timedelta.
     if (!hasattr(src, "days") || !hasattr(src, "seconds") ||
@@ -143,8 +164,6 @@ struct type_caster<absl::Duration> {
     }
     return true;
   }
-    return false;
-  }
 
   // Conversion part 2 (C++ -> Python)
   static handle cast(const absl::Duration& src, return_value_policy, handle) {
@@ -172,15 +191,32 @@ struct type_caster<absl::Time> {
 
   // Conversion part 1 (Python->C++)
   bool load(handle src, bool convert) {
+    // As early as possible to avoid mid-process surprises.
+    internal::EnsurePyDateTime_IMPORT();
     if (convert) {
       if (PyLong_Check(src.ptr())) {
         value = absl::FromUnixSeconds(src.cast<int64_t>());
         return true;
-      } else if (PyFloat_Check(src.ptr())) {
+      }
+      if (PyFloat_Check(src.ptr())) {
         value = absl::time_internal::FromUnixDuration(absl::Seconds(
             src.cast<double>()));
         return true;
       }
+      if (PyTime_Check(src.ptr())) {
+        // Adapted from absl/python/time.cc
+        // Copyright 2018 The Abseil Authors.
+        timeval tv{PyDateTime_TIME_GET_HOUR(src.ptr()) * 3600 +
+                       PyDateTime_TIME_GET_MINUTE(src.ptr()) * 60 +
+                       PyDateTime_TIME_GET_SECOND(src.ptr()),
+                   PyDateTime_TIME_GET_MICROSECOND(src.ptr())};
+        value = absl::TimeFromTimeval(tv);
+        int utcoffset;
+        if (PyTzOffset(src.ptr(), &utcoffset)) {
+          value += absl::Seconds(utcoffset);
+        }
+        return true;
+      }
     }
     if (!hasattr(src, "year") || !hasattr(src, "month") ||
         !hasattr(src, "day")) {
@@ -233,6 +269,25 @@ struct type_caster<absl::Time> {
     auto py_datetime = py_from_timestamp(as_seconds, "tz"_a = py_timezone);
     return py_datetime.release();
   }
+
+ private:
+  // Adapted from absl/python/time.cc
+  // Copyright 2018 The Abseil Authors.
+  bool PyTzOffset(PyObject* datetime, int* utcoffset) {
+    PyObject* offset = PyObject_CallMethod(datetime, "utcoffset", nullptr);
+
+    if (!offset || !PyDelta_Check(offset)) {
+      return false;
+    }
+
+    if (utcoffset) {
+      *utcoffset = PyDateTime_DELTA_GET_SECONDS(offset) +
+                   PyDateTime_DELTA_GET_DAYS(offset) * 24 * 3600;
+    }
+
+    Py_DECREF(offset);
+    return true;
+  }
 };
 
 template <typename CivilTimeUnitType>

pybind11_abseil/tests/absl_example.cc

@@ -98,6 +98,12 @@ bool CheckCivilYear(absl::CivilYear datetime, double secs) {
   return datetime == MakeCivilYear(secs);
 }
 
+absl::Duration RoundtripDuration(const absl::Duration& duration) {
+  return duration;
+}
+
+absl::Time RoundtripTime(const absl::Time& time) { return time; }
+
 absl::TimeZone RoundtripTimeZone(absl::TimeZone timezone) { return timezone; }
 
 // Since a span does not own its elements, we must create a class to own them
@@ -340,7 +346,8 @@ PYBIND11_MODULE(absl_example, m) {
   m.def("absl_time_overloads", [](int) {  return "int"; });
   m.def("absl_time_overloads", [](float) { return "float"; });
 
-  // absl::TimeZone bindings
+  m.def("roundtrip_duration", &RoundtripDuration, arg("duration"));
+  m.def("roundtrip_time", &RoundtripTime, arg("time"));
   m.def("roundtrip_timezone", &RoundtripTimeZone, arg("timezone"));
 
   // absl::CivilTime bindings

pybind11_abseil/tests/absl_test.py

@@ -15,6 +15,12 @@ import numpy as np
 from pybind11_abseil.tests import absl_example
 
 
+def dt_time(h=0, m=0, s=0, micros=0, tzoff=0):
+  return datetime.time(h, m, s, micros).replace(
+      tzinfo=datetime.timezone(datetime.timedelta(seconds=tzoff))
+  )
+
+
 class AbslTimeTest(parameterized.TestCase):
   SECONDS_IN_DAY = 24 * 60 * 60
   POSITIVE_SECS = 3 * SECONDS_IN_DAY + 2.5
@@ -242,6 +248,29 @@ class AbslTimeTest(parameterized.TestCase):
     with self.assertRaises(TypeError):
       absl_example.roundtrip_timezone('Not a timezone')
 
+  @parameterized.parameters(
+      absl_example.roundtrip_duration, absl_example.roundtrip_time
+  )
+  def test_from_datetime_time(self, rt):
+    dt1 = rt(dt_time(h=13))
+    dt2 = rt(dt_time(h=15))
+    self.assertEqual((dt2 - dt1).seconds, 2 * 3600)
+    dt1 = rt(dt_time(m=12))
+    dt2 = rt(dt_time(m=16))
+    self.assertEqual((dt2 - dt1).seconds, 4 * 60)
+    dt1 = rt(dt_time(s=11))
+    dt2 = rt(dt_time(s=17))
+    self.assertEqual((dt2 - dt1).seconds, 6)
+    dt1 = rt(dt_time(micros=10))
+    dt2 = rt(dt_time(micros=18))
+    self.assertEqual((dt2 - dt1).microseconds, 8)
+    dt1 = rt(dt_time(tzoff=9))
+    dt2 = rt(dt_time(tzoff=19))
+    # Conversion from datetime.time to absl::Duration ignores tzinfo!
+    self.assertEqual(
+        (dt2 - dt1).seconds, 0 if rt is absl_example.roundtrip_duration else 10
+    )
+
 
 def make_read_only_numpy_array():
   values = np.zeros(5, dtype=np.int32)