build_ext.py

import os
import pathlib

from setuptools import Extension
from setuptools.command.build_ext import build_ext


class CMakeExtension(Extension):
    """
    Stub class to distinguish between default extensions and CMake
    extensions (which contain no sources as these are listed in the
    CMakeLists.txt file)
    """

    def __init__(self, name):
        # don't invoke the original build_ext for this special extension
        super().__init__(name, sources=[])


class cmakeable_build_ext(build_ext):
    """
    build_ext compatible class which detects if the extension it is to
    build is a CMakeExtension in which case it delegates building to
    the CMake executable.
    """

    def run(self):
        for ext in self.extensions:
            if isinstance(ext, CMakeExtension):
                self.build_cmake(ext)
        super().run()

    def copy_extensions_to_source(self):
        # install is handled by cmake
        pass

    def build_cmake(self, ext):
        cwd = pathlib.Path().absolute()

        # Create directory structure
        build_temp = pathlib.Path(self.build_temp)
        if not build_temp.exists():
            build_temp.mkdir(parents=True, exist_ok=True)
        extdir = pathlib.Path(self.get_ext_fullpath(ext.name))
        if not extdir.exists():
            extdir.mkdir(parents=True, exist_ok=True)

        # Check which architecture we should be building for
        import struct

        bits = struct.calcsize("P") * 8

        # Setup args passed to cmake
        config = "Debug" if self.debug else "Release"
        cmake_config_args = [
            "-DCMAKE_INSTALL_PREFIX=" + str(extdir.parent.absolute()),
            "-DCMAKE_BUILD_TYPE=" + config,
            "-DSETUPTOOLS_BUILD=1",
        ]
        if os.name == "nt":
            if bits == 64:
                cmake_config_args.append("-A x64")
            elif bits == 32:
                cmake_config_args.append("-A Win32")
            else:
                raise RuntimeError(f"Unknown computer architecture with {bits} bits")
        else:
            if bits == 32:
                cmake_config_args.append("-DCOMPILE_32_BITS=1")

        # Disable warning MSB8029 (https://stackoverflow.com/a/60301902/5194459)
        os.environ["IgnoreWarnIntDirInTempDetected"] = "true"

        os.chdir(str(build_temp))
        self.spawn(["cmake", str(cwd)] + cmake_config_args)
        if not self.dry_run:  # pyright: ignore
            cmake_build_args = [
                "--build",
                ".",
                "--target",
                "install",
                "--config",
                config,
            ]
            self.spawn(["cmake"] + cmake_build_args)
        os.chdir(str(cwd))


def build(setup_kwargs):
    setup_kwargs.update(
        {
            "ext_modules": [CMakeExtension("endplay")],
            "cmdclass": {"build_ext": cmakeable_build_ext},
        }
    )