build_extension.py

# SPDX-FileCopyrightText: 2023 Gabriele Pongelli
#
# SPDX-License-Identifier: MIT

"""Module to build C/C++ extension with Poetry."""

import configparser
import os
import platform
from glob import glob
from os.path import join, relpath, splitext
from pathlib import Path

from setuptools.command.develop import develop
from setuptools.extension import Extension

# arch information comes from
# gcc -v
# gcc -dumpmachine

# info
#  https://stackoverflow.com/questions/6928110/how-may-i-override-the-compiler-gcc-flags-that-setup-py-uses-by-default

print(f"SYSTEM: {platform.system()}")
print(f"MACHINE: {platform.machine()}")
print(f"UNAME: {platform.uname()}")
print(f"RELEASE: {platform.release()}")
print(f"VERSION: {platform.version()}")
print(f"PROCESSOR: {platform.processor()}")

_platform = platform.system().lower()
_is_windows = 'windows' in _platform  # pylint: disable=C0103
_arch = 'x86-64'  # pylint: disable=C0103
_c_compiler = ""  # pylint: disable=C0103
if _is_windows:
    _lflags = f"-Wl,--subsystem,windows,--out-implib,libcode128_{_arch}.a"
    _c_compiler = "mingw32"  # pylint: disable=C0103
else:
    # if "linux" in _platform:
    _c_compiler = "unix"  # pylint: disable=C0103
    _lflags = "-Wl,-soname,libcode128.so"  # pylint: disable=C0103
    if 'arm' in platform.machine():
        _arch = "armv7"  # pylint: disable=C0103
    elif 'aarch64' in platform.machine():
        _arch = "armv8.8-a"  # pylint: disable=C0103

_march = f"-march={_arch}"  # pylint: disable=C0103
if 'darwin' in _platform:
    _march = ""  # pylint: disable=C0103  # clang compiler does not support -march=x86_64


# list of tuples (python_module, dict of C/C++ library build data ),
#   python_module is the extension that uses those C/C++ library info.
# the dict can be extended with all the kwargs needed by Extension to correctly build C/C++ sourcecode
_LIBS = [
    (
        'pycode128',
        {
            "libs": ['libs/code128'],
            # Building library part
            "lib_cflags": ["-O2", "-std=c99", "-Wall", "-fpic", "-Wextra", _march, "-DADD_EXPORTS"],
            "lib_lflags": ["-shared", _lflags],
            # Python extension part
            # always define PY_SSIZE_T_CLEAN , see https://docs.python.org/3/extending/extending.html
            "extension_define_macros": [("PY_SSIZE_T_CLEAN", None), ("ADD_EXPORTS", None)],
            "extension_language": "c99",
            "extension_extra_compile_args": [],
            "extension_extra_link_args": [],
            "extension_library": ['code128'],
        },
    )
]


class CustomDevelop(develop):
    """Custom install procedure.

    When declaring a ``build_extension.py`` poetry switches to setuptools during
    installation, i.e., it generates a temporary ``setup.py`` and then calls
    ``setup.py develop`` on it when you call ``poetry install``.
    Consequentially, we can hook into the develop command and customize the
    build to compile our source :) Note that this is only needed for the
    ``develop`` command, because the ``build`` command (``poetry build``)
    already includes ``build_clib``.

    This class then is the hook that will compile the source when we call
    ``poetry install``.

    """

    def run(self) -> None:  # type: ignore
        # build archives (.lib) these are declared in the `libraries` kwarg of
        # setup(). Extensions may depend on these, so we have to build the libs
        # them first.
        self.run_command("build_clib")
        super().run()


# custom_extension = Extension(
#     "pycode128.pycode128",
#     sources=["pycode128/pycode128.c"],
#     # define_macros=[("PY_SSIZE_T_CLEAN",)],
#     # we need to declare the extenal dependencies
#     include_dirs=["libs/code128"],
#     libraries=["code128"],  # see below
# )


def _add_compiler_to_setup_cfg(_compiler):
    conf = configparser.ConfigParser(inline_comment_prefixes="#")

    with open(Path(os.path.realpath(os.path.dirname(__file__))) / 'setup.cfg', mode='r', encoding="cp1252") as _fp:
        try:
            conf.read_file(_fp)
        except configparser.Error:
            pass

    try:
        conf.set('build_clib', 'compiler', _compiler)
    except configparser.NoSectionError:
        conf.add_section('build_clib')
        conf.set('build_clib', 'compiler', _compiler)

    try:
        conf.set('build_ext', 'compiler', _compiler)
    except configparser.NoSectionError:
        conf.add_section('build_ext')
        conf.set('build_ext', 'compiler', _compiler)

    with open('setup.cfg', mode='w', encoding="cp1252") as _fp:
        conf.write(_fp, space_around_delimiters=True)


# setuptools.extension requires unix separator
def _unix_form(file_path: str) -> str:
    return file_path.replace('\\', '/')


def build(setup_kwargs):
    """
    This is a callback for poetry used to hook in our extensions.
    """

    _add_compiler_to_setup_cfg(_c_compiler)

    setup_kwargs.update(
        {
            # declare archives (.lib) to build. These will be linked to
            # statically by extensions, cython, ...
            "libraries": [
                (
                    "code128",
                    {
                        "sources": [
                            _unix_form(path)
                            for _, _source_libs in _LIBS
                            for _source_folder in _source_libs['libs']
                            for root, _, _ in os.walk(os.sep.join([_source_folder]))
                            for path in glob(join(root, '*.c'))
                            if 'code128png' not in path
                        ],
                        # flags and dependencies of this library
                        # "include_dirs": ...
                        # "libraries": ...
                        "cflags": [
                            itm
                            for pylib, _source_libs in _LIBS
                            for itm in _source_libs['lib_cflags']
                            if pylib == 'pycode128'
                        ],
                        "lflags": [
                            itm
                            for pylib, _source_libs in _LIBS
                            for itm in _source_libs['lib_lflags']
                            if pylib == 'pycode128'
                        ],
                    },
                ),
            ],
            "ext_modules": [
                Extension(
                    splitext(relpath(_unix_form(path), start='.').replace(os.sep, '.'))[0],
                    sources=[_unix_form(path)],
                    define_macros=_source_libs['extension_define_macros'],
                    include_dirs=_source_libs['libs'],
                    libraries=_source_libs['extension_library'],
                    language=_source_libs["extension_language"],
                    extra_compile_args=_source_libs["extension_extra_compile_args"],
                    extra_link_args=_source_libs["extension_extra_link_args"],
                )
                for _py_lib, _source_libs in _LIBS
                for root, _, _ in os.walk(os.sep.join([_py_lib]))
                for path in glob(join(root, '*.c'))
            ],
            # hook into the build process to build our external sources before
            # we build and install the package.
            "cmdclass": {"develop": CustomDevelop},
        }
    )


#
# if __name__ == '__main__':
#     # _LIBS = [('py', 'libs/code128')]
#
#     for _py_lib, _source_libs in _LIBS:
#         for _source_folder in _source_libs['libs']:
#             for root, _, _ in os.walk(os.sep.join([_source_folder])):
#                 print(root)
#                 for path in glob(join(root, '*.c')):
#                     print(path)
#                     print(dirname(path))
#
#     _a = [_unix_form(path)
#           for _py_lib, _source_lib in _LIBS
#           for source_fold in _source_lib['libs']
#           for root, _, _ in os.walk(os.sep.join([source_fold]))
#           for path in glob(join(root, '*.c'))
#           if 'code128png' not in path]
#
#     for _py_lib, _ in _LIBS:
#         for root, _, _ in os.walk(os.sep.join([_py_lib])):
#             print(root)
#             for path in glob(join(root, '*.c')):
#                 print(path)
#                 print(dirname(path))
#                 print(splitext(relpath(path, start='.').replace(os.sep, '.'))[0])
#
#     ext = [Extension(splitext(relpath(_unix_form(path), start='.').replace(os.sep, '.'))[0],
#                      sources=[_unix_form(path)],
#                      define_macros=_source_libs['define_macros'],
#                      include_dirs=_source_libs['libs'])
#            for _py_lib, _source_libs in _LIBS
#            for root, _, _ in os.walk(os.sep.join([_py_lib]))
#            for path in glob(join(root, '*.c'))
#            ]
#     print(ext)
#
#