Replace c extension with cython versions.workflow_test_cython

Re-implement c version immutabledict / processors / resultproxy / utils with cython.
Performance is in general in par or better than the c version
Added a collection module that has cython version of OrderedSet and IdentitySet

Added a new test/perf file to compare the implementations.
Run ``python test/perf/compiled_extensions.py all`` to execute the comparison test.

See results here: https://docs.google.com/document/d/1nOcDGojHRtXEkuy4vNXcW_XOJd9gqKhSeALGG3kYr6A/edit?usp=sharing

Fixes: #7256
Change-Id: I2930ef1894b5048210384728118e586e813f6a76
Signed-off-by: Federico Caselli <cfederico87@gmail.com>

1 files changed, 91 insertions, 0 deletions

diff --git a/lib/sqlalchemy/cyextension/processors.pyx b/lib/sqlalchemy/cyextension/processors.pyx
new file mode 100644
index 000000000..9f23e73b1
--- /dev/null
+++ b/lib/sqlalchemy/cyextension/processors.pyx
@@ -0,0 +1,91 @@
+import datetime
+import re
+
+from cpython.datetime cimport date_new, datetime_new, import_datetime, time_new
+from cpython.object cimport PyObject_Str
+from cpython.unicode cimport PyUnicode_AsASCIIString, PyUnicode_Check, PyUnicode_Decode
+from libc.stdio cimport sscanf
+
+
+def int_to_boolean(value):
+    if value is None:
+        return None
+    return True if value else False
+
+def to_str(value):
+    return PyObject_Str(value) if value is not None else None
+
+def to_float(value):
+    return float(value) if value is not None else None
+
+cdef inline bytes to_bytes(object value, str type_name):
+    try:
+        return PyUnicode_AsASCIIString(value)
+    except Exception as e:
+        raise ValueError(
+            f"Couldn't parse {type_name} string '{value!r}' "
+            "- value is not a string."
+        ) from e
+
+import_datetime()  # required to call datetime_new/date_new/time_new
+
+def str_to_datetime(value):
+    if value is None:
+        return None
+    cdef int numparsed
+    cdef unsigned int year, month, day, hour, minute, second, microsecond = 0
+    cdef bytes value_b = to_bytes(value, 'datetime')
+    cdef const char * string = value_b
+
+    numparsed = sscanf(string, "%4u-%2u-%2u %2u:%2u:%2u.%6u",
+        &year, &month, &day, &hour, &minute, &second, &microsecond)
+    if numparsed < 6:
+        raise ValueError(
+                "Couldn't parse datetime string: '%s'" % (value)
+            )
+    return datetime_new(year, month, day, hour, minute, second, microsecond, None)
+
+def str_to_date(value):
+    if value is None:
+        return None
+    cdef int numparsed
+    cdef unsigned int year, month, day
+    cdef bytes value_b = to_bytes(value, 'date')
+    cdef const char * string = value_b
+
+    numparsed = sscanf(string, "%4u-%2u-%2u", &year, &month, &day)
+    if numparsed != 3:
+        raise ValueError(
+                "Couldn't parse date string: '%s'" % (value)
+            )
+    return date_new(year, month, day)
+
+def str_to_time(value):
+    if value is None:
+        return None
+    cdef int numparsed
+    cdef unsigned int hour, minute, second, microsecond = 0
+    cdef bytes value_b = to_bytes(value, 'time')
+    cdef const char * string = value_b
+
+    numparsed = sscanf(string, "%2u:%2u:%2u.%6u", &hour, &minute, &second, &microsecond)
+    if numparsed < 3:
+        raise ValueError(
+                "Couldn't parse time string: '%s'" % (value)
+            )
+    return time_new(hour, minute, second, microsecond, None)
+
+
+cdef class DecimalResultProcessor:
+    cdef object type_
+    cdef str format_
+
+    def __cinit__(self, type_, format_):
+        self.type_ = type_
+        self.format_ = format_
+
+    def process(self, object value):
+        if value is None:
+            return None
+        else:
+            return self.type_(self.format_ % value)