Revert "Use PyCapsule for internal datetime functions" (#51951)

Revert "Use PyCapsule for internal datetime functions (#51525)"

This reverts commit 251b512.

MANIFEST.in

@@ -58,5 +58,3 @@ prune pandas/tests/io/parser/data
 # Selectively re-add *.cxx files that were excluded above
 graft pandas/_libs/src
 graft pandas/_libs/tslibs/src
-include pandas/_libs/pd_parser.h
-include pandas/_libs/pd_parser.c

pandas/_libs/__init__.py

@@ -10,11 +10,6 @@
 ]
 
 
-# Below imports needs to happen first to ensure pandas top level
-# module gets monkeypatched with the pandas_datetime_CAPI
-# see pandas_datetime_exec in pd_datetime.c
-import pandas._libs.pandas_parser  # noqa # isort: skip # type: ignore[reportUnusedImport]
-import pandas._libs.pandas_datetime  # noqa # isort: skip # type: ignore[reportUnusedImport]
 from pandas._libs.interval import Interval
 from pandas._libs.tslibs import (
     NaT,

pandas/_libs/index.pyx

@@ -20,12 +20,7 @@ from pandas._libs.tslibs.nattype cimport c_NaT as NaT
 from pandas._libs.tslibs.np_datetime cimport (
     NPY_DATETIMEUNIT,
     get_unit_from_dtype,
-    import_pandas_datetime,
 )
-
-import_pandas_datetime()
-
-
 from pandas._libs.tslibs.period cimport is_period_object
 from pandas._libs.tslibs.timedeltas cimport _Timedelta
 from pandas._libs.tslibs.timestamps cimport _Timestamp

pandas/_libs/lib.pyx

@@ -88,11 +88,9 @@ cdef extern from "numpy/arrayobject.h":
 cdef extern from "numpy/ndarrayobject.h":
     bint PyArray_CheckScalar(obj) nogil
 
-cdef extern from "pd_parser.h":
-    int floatify(object, float64_t *result, int *maybe_int) except -1
-    void PandasParser_IMPORT()
 
-PandasParser_IMPORT
+cdef extern from "src/parse_helper.h":
+    int floatify(object, float64_t *result, int *maybe_int) except -1
 
 from pandas._libs cimport util
 from pandas._libs.util cimport (

pandas/_libs/missing.pyx

@@ -34,11 +34,8 @@ from pandas._libs.tslibs.np_datetime cimport (
     get_datetime64_unit,
     get_datetime64_value,
     get_timedelta64_value,
-    import_pandas_datetime,
 )
 
-import_pandas_datetime()
-
 from pandas._libs.ops_dispatch import maybe_dispatch_ufunc_to_dunder_op
 
 cdef:

pandas/_libs/parsers.pyx

@@ -229,9 +229,9 @@ cdef extern from "parser/tokenizer.h":
         int64_t skip_first_N_rows
         int64_t skipfooter
         # pick one, depending on whether the converter requires GIL
-        double (*double_converter)(const char *, char **,
-                                   char, char, char,
-                                   int, int *, int *) nogil
+        float64_t (*double_converter)(const char *, char **,
+                                      char, char, char,
+                                      int, int *, int *) nogil
 
         #  error handling
         char *warn_msg
@@ -249,16 +249,6 @@ cdef extern from "parser/tokenizer.h":
         int seen_uint
         int seen_null
 
-    void COLITER_NEXT(coliter_t, const char *) nogil
-
-cdef extern from "pd_parser.h":
-    void *new_rd_source(object obj) except NULL
-
-    int del_rd_source(void *src)
-
-    void* buffer_rd_bytes(void *source, size_t nbytes,
-                          size_t *bytes_read, int *status, const char *encoding_errors)
-
     void uint_state_init(uint_state *self)
     int uint64_conflict(uint_state *self)
 
@@ -289,49 +279,26 @@ cdef extern from "pd_parser.h":
     uint64_t str_to_uint64(uint_state *state, char *p_item, int64_t int_max,
                            uint64_t uint_max, int *error, char tsep) nogil
 
-    double xstrtod(const char *p, char **q, char decimal,
-                   char sci, char tsep, int skip_trailing,
-                   int *error, int *maybe_int) nogil
-    double precise_xstrtod(const char *p, char **q, char decimal,
-                           char sci, char tsep, int skip_trailing,
-                           int *error, int *maybe_int) nogil
-    double round_trip(const char *p, char **q, char decimal,
+    float64_t xstrtod(const char *p, char **q, char decimal,
                       char sci, char tsep, int skip_trailing,
                       int *error, int *maybe_int) nogil
+    float64_t precise_xstrtod(const char *p, char **q, char decimal,
+                              char sci, char tsep, int skip_trailing,
+                              int *error, int *maybe_int) nogil
+    float64_t round_trip(const char *p, char **q, char decimal,
+                         char sci, char tsep, int skip_trailing,
+                         int *error, int *maybe_int) nogil
 
     int to_boolean(const char *item, uint8_t *val) nogil
 
-    void PandasParser_IMPORT()
-
-PandasParser_IMPORT
-
-# When not invoked directly but rather assigned as a function,
-# cdef extern'ed declarations seem to leave behind an undefined symbol
-cdef double xstrtod_wrapper(const char *p, char **q, char decimal,
-                            char sci, char tsep, int skip_trailing,
-                            int *error, int *maybe_int) nogil:
-    return xstrtod(p, q, decimal, sci, tsep, skip_trailing, error, maybe_int)
-
-
-cdef double precise_xstrtod_wrapper(const char *p, char **q, char decimal,
-                                    char sci, char tsep, int skip_trailing,
-                                    int *error, int *maybe_int) nogil:
-    return precise_xstrtod(p, q, decimal, sci, tsep, skip_trailing, error, maybe_int)
-
-
-cdef double round_trip_wrapper(const char *p, char **q, char decimal,
-                               char sci, char tsep, int skip_trailing,
-                               int *error, int *maybe_int) nogil:
-    return round_trip(p, q, decimal, sci, tsep, skip_trailing, error, maybe_int)
 
+cdef extern from "parser/io.h":
+    void *new_rd_source(object obj) except NULL
 
-cdef void* buffer_rd_bytes_wrapper(void *source, size_t nbytes,
-                                   size_t *bytes_read, int *status,
-                                   const char *encoding_errors) noexcept:
-    return buffer_rd_bytes(source, nbytes, bytes_read, status, encoding_errors)
+    int del_rd_source(void *src)
 
-cdef int del_rd_source_wrapper(void *src) noexcept:
-    return del_rd_source(src)
+    void* buffer_rd_bytes(void *source, size_t nbytes,
+                          size_t *bytes_read, int *status, const char *encoding_errors)
 
 
 cdef class TextReader:
@@ -518,11 +485,11 @@ cdef class TextReader:
 
         if float_precision == "round_trip":
             # see gh-15140
-            self.parser.double_converter = round_trip_wrapper
+            self.parser.double_converter = round_trip
         elif float_precision == "legacy":
-            self.parser.double_converter = xstrtod_wrapper
+            self.parser.double_converter = xstrtod
         elif float_precision == "high" or float_precision is None:
-            self.parser.double_converter = precise_xstrtod_wrapper
+            self.parser.double_converter = precise_xstrtod
         else:
             raise ValueError(f"Unrecognized float_precision option: "
                              f"{float_precision}")
@@ -640,8 +607,8 @@ cdef class TextReader:
 
         ptr = new_rd_source(source)
         self.parser.source = ptr
-        self.parser.cb_io = buffer_rd_bytes_wrapper
-        self.parser.cb_cleanup = del_rd_source_wrapper
+        self.parser.cb_io = &buffer_rd_bytes
+        self.parser.cb_cleanup = &del_rd_source
 
     cdef _get_header(self, list prelim_header):
         # header is now a list of lists, so field_count should use header[0]