Distutils：将 Objective-C++ 源文件编译为 C++ 扩展的一部分

Question

我正在用 C++ 编写 Python 扩展。我通过在 setup.py 文件中定义组成源文件的列表来编译它，如下所示：

extensions = {
    'im': [
        "im/src/buffer.cpp",
        "im/src/detail.cpp",
        "im/src/gil.cpp",
        "im/src/halideimage.cpp",
        "im/src/hybrid.cpp",
        "im/src/hybridimage.cpp",
        "im/src/options.cpp",
        "im/src/pybuffer.cpp",
        "im/src/pycapsule.cpp",
        "im/src/structcode.cpp",
        "im/src/typecode.cpp",
        "im/src/module.cpp"
    ],
}

...这些用于定义setuptools.Extension 的实例，最终传递给setup() 函数。这在整个项目中都运行良好，直到现在，当我尝试添加一个特定于平台的位时：

preview_source = (sys.platform == 'darwin') and 'im/src/plat/preview_mac.mm' or \
                  (sys.platform == 'linux') and 'im/src/plat/preview_linux.cpp' or \
                  (sys.platform == 'win32') and 'im/src/plat/preview_windows.cpp' or \
                                                'im/src/plat/preview.cpp'

extensions = {
    'im': [
        "im/src/buffer.cpp",
        "im/src/detail.cpp",
        "im/src/gil.cpp",
        "im/src/halideimage.cpp",
        "im/src/hybrid.cpp",
        "im/src/hybridimage.cpp",
        "im/src/options.cpp",
        preview_source,
        "im/src/pybuffer.cpp",
        "im/src/pycapsule.cpp",
        "im/src/structcode.cpp",
        "im/src/typecode.cpp",
        "im/src/module.cpp"
    ],
}

... 添加这个新位会选择正确的文件进行编译——但它在 Mac OS X 上根本无法编译。显然distutils/setuptools 无法将“.mm”扩展名识别为源文件：

错误：未知文件类型“.mm”

对于distutils 和setuptools 特定于平台的配置，我不是专家——有什么简单的方法可以有条件地将这个源文件添加到 Mac 上的源文件列表中？

Answer 1

我遇到了同样的问题，你有没有找到解决办法？

我的 distutils 版本似乎不支持“.mm”，但“.m”支持。所以我将 .mm 文件的 C++ 部分分离成一个 .cpp 文件，并创建一个小的 C 头文件以从该 .cpp 访问 .m 文件。

Answer 2

我正在开展一个遇到此问题的项目。这是我放在一起的东西。它有点老套，但它确实有效。

from distutils.unixccompiler import UnixCCompiler
from setuptools import setup
from setuptools.command.build_ext import build_ext

class DarwinInteropBuildExt(build_ext):
    def initialize_options(self):

        # add support for ".mm" files
        UnixCCompiler.src_extensions.append(".mm")
        UnixCCompiler.language_map[".mm"] = "objc"

        # then intercept and patch the compile and link methods to add needed flags
        unpatched_compile = UnixCCompiler._compile
        unpatched_link = UnixCCompiler.link

        def patched_compile(self, obj, src, ext, cc_args, extra_postargs, pp_opts):
            # define language specific compile flags here
            if ext == ".cpp":
                patched_postargs = extra_postargs + ["-std=c++17"]
            elif ext == ".mm":
                patched_postargs = extra_postargs + [
                    "-ObjC++",
                    "-fobjc-weak",
                    "-fobjc-arc",
                ]
            else:
                patched_postargs = extra_postargs
            unpatched_compile(self, obj, src, ext, cc_args, patched_postargs, pp_opts)

        def patched_link(
                self,
                target_desc,
                objects,
                output_filename,
                output_dir=None,
                libraries=None,
                library_dirs=None,
                runtime_library_dirs=None,
                export_symbols=None,
                debug=0,
                extra_preargs=None,
                extra_postargs=None,
                build_temp=None,
                target_lang=None,
        ):
            # define additional linking arguments here if needed
            existing_postargs = extra_postargs or []
            framework_postargs = [
                "-framework", "Cocoa",
                "-framework", "Metal",
                "-framework", "QuartzCore",
            ]
            unpatched_link(
                self,
                target_desc,
                objects,
                output_filename,
                output_dir,
                libraries,
                library_dirs,
                runtime_library_dirs,
                export_symbols,
                debug,
                extra_preargs,
                existing_postargs + framework_postargs,
                build_temp,
                target_lang,
            )
        UnixCCompiler._compile = patched_compile
        UnixCCompiler.link = patched_link
        super().initialize_options()

# ...


setup(
    # use the custom cmd class here
    cmdclass={"build_ext": DarwinInteropBuildExt},
)