build_ext.py 文件源码

def copy_extensions_to_source(self):
        build_py = self.get_finalized_command('build_py')
        for ext in self.extensions:
            fullname = self.get_ext_fullname(ext.name)
            filename = self.get_ext_filename(fullname)
            modpath = fullname.split('.')
            package = '.'.join(modpath[:-1])
            package_dir = build_py.get_package_dir(package)
            dest_filename = os.path.join(package_dir,
                                         os.path.basename(filename))
            src_filename = os.path.join(self.build_lib, filename)

            # Always copy, even if source is older than destination, to ensure
            # that the right extensions for the current Python/platform are
            # used.
            copy_file(
                src_filename, dest_filename, verbose=self.verbose,
                dry_run=self.dry_run
            )
            if ext._needs_stub:
                self.write_stub(package_dir or os.curdir, ext, True)