refactor(python): Extract utility functions into _utils.pyx (#529)

This PR moves a number of utility functions that were relatively
self-contained into a new module, _utils.pyx.

TODO:

- dereplicate the error handling utility
- Ensure "exported" functions are documented with a docstring

python/.gitignore

@@ -17,8 +17,7 @@
 # under the License.
 
 vendor/
-src/nanoarrow/_lib.c
-src/nanoarrow/_ipc_lib.c
+src/nanoarrow/_*.c
 
 # Byte-compiled / optimized / DLL files
 __pycache__/

python/setup.py

@@ -67,6 +67,18 @@ def get_version(pkg_path):
 
 setup(
     ext_modules=[
+        Extension(
+            name="nanoarrow._utils",
+            include_dirs=["src/nanoarrow", "vendor"],
+            language="c",
+            sources=[
+                "src/nanoarrow/_utils.pyx",
+                "vendor/nanoarrow.c",
+            ],
+            extra_compile_args=extra_compile_args,
+            extra_link_args=extra_link_args,
+            define_macros=extra_define_macros,
+        ),
         Extension(
             name="nanoarrow._lib",
             include_dirs=["src/nanoarrow", "vendor"],

python/src/nanoarrow/__init__.py

@@ -24,7 +24,7 @@
 Arrow C Data and Arrow C Stream interfaces.
 """
 
-from nanoarrow._lib import c_version
+from nanoarrow._utils import c_version
 from nanoarrow.c_array import c_array_from_buffers, c_array
 from nanoarrow.c_array_stream import c_array_stream
 from nanoarrow.c_schema import c_schema