REF: implement ABCTimestamp, ABCTimedelta, ABCTick (pandas-dev#34054)

Author: jbrockmendel

pandas/_libs/index.pyx

@@ -23,7 +23,7 @@ cimport pandas._libs.util as util
 
 from pandas._libs.tslibs import Period, Timedelta
 from pandas._libs.tslibs.nattype cimport c_NaT as NaT
-from pandas._libs.tslibs.c_timestamp cimport _Timestamp
+from pandas._libs.tslibs.base cimport ABCTimestamp
 
 from pandas._libs.hashtable cimport HashTable
 
@@ -378,7 +378,7 @@ cdef class DatetimeEngine(Int64Engine):
     cdef int64_t _unbox_scalar(self, scalar) except? -1:
         # NB: caller is responsible for ensuring tzawareness compat
         #  before we get here
-        if not (isinstance(scalar, _Timestamp) or scalar is NaT):
+        if not (isinstance(scalar, ABCTimestamp) or scalar is NaT):
             raise TypeError(scalar)
         return scalar.value
 

pandas/_libs/tslib.pyx

@@ -26,7 +26,7 @@ from pandas._libs.util cimport (
     is_integer_object,
 )
 
-from pandas._libs.tslibs.c_timestamp cimport _Timestamp
+from pandas._libs.tslibs.base cimport ABCTimestamp
 
 from pandas._libs.tslibs.np_datetime cimport (
     _string_to_dts,
@@ -617,7 +617,7 @@ cpdef array_to_datetime(
                                              'datetime64 unless utc=True')
                     else:
                         iresult[i] = pydatetime_to_dt64(val, &dts)
-                        if isinstance(val, _Timestamp):
+                        if isinstance(val, ABCTimestamp):
                             iresult[i] += val.nanosecond
                         check_dts_bounds(&dts)
 

pandas/_libs/tslibs/__init__.py

@@ -21,8 +21,5 @@
 from .np_datetime import OutOfBoundsDatetime
 from .period import IncompatibleFrequency, Period
 from .timedeltas import Timedelta, delta_to_nanoseconds, ints_to_pytimedelta
-from .timestamps import Timestamp
+from .timestamps import NullFrequencyError, Timestamp
 from .tzconversion import tz_convert_single
-
-# import fails if we do this before np_datetime
-from .c_timestamp import NullFrequencyError  # isort:skip

pandas/_libs/tslibs/base.pxd

@@ -0,0 +1,20 @@
+from cpython.datetime cimport datetime, timedelta
+
+cdef class ABCTimedelta(timedelta):
+    pass
+
+
+cdef class ABCTimestamp(datetime):
+    pass
+
+
+cdef class ABCTick:
+    pass
+
+
+cdef class ABCPeriod:
+    pass
+
+
+cdef bint is_tick_object(object obj)
+cdef bint is_period_object(object obj)

pandas/_libs/tslibs/base.pyx

@@ -0,0 +1,32 @@
+"""
+We define base classes that will be inherited by Timestamp, Timedelta, etc
+in order to allow for fast isinstance checks without circular dependency issues.
+
+This is analogous to core.dtypes.generic.
+"""
+
+from cpython.datetime cimport datetime, timedelta
+
+
+cdef class ABCTimedelta(timedelta):
+    pass
+
+
+cdef class ABCTimestamp(datetime):
+    pass
+
+
+cdef class ABCPeriod:
+    pass
+
+
+cdef class ABCTick:
+    pass
+
+
+cdef bint is_tick_object(object obj):
+    return isinstance(obj, ABCTick)
+
+
+cdef bint is_period_object(object obj):
+    return isinstance(obj, ABCPeriod)