setup.py

"""A setuptools based setup module.

See:
https://packaging.python.org/guides/distributing-packages-using-setuptools/
https://github.com/pypa/sampleproject
"""

# Always prefer setuptools over distutils
from setuptools import setup, Extension, Command
import os
import warnings

# stuff to check presence of compiler:
import distutils.sysconfig
import distutils.ccompiler
from distutils.errors import CompileError, DistutilsPlatformError

setup_path = os.path.abspath(os.path.dirname(__file__))


# Extensions. Add your extension here:
raw_extensions = [
    Extension(
        "rsciio.bruker.unbcf_fast", [os.path.join("rsciio", "bruker", "unbcf_fast.pyx")]
    ),
]

cleanup_list = []
for leftover in raw_extensions:
    path, ext = os.path.splitext(leftover.sources[0])
    if ext in (".pyx", ".py"):
        cleanup_list.append("".join([os.path.join(setup_path, path), ".c*"]))
        if os.name == "nt":
            bin_ext = ".cpython-*.pyd"
        else:
            bin_ext = ".cpython-*.so"
        cleanup_list.append("".join([os.path.join(setup_path, path), bin_ext]))


def count_c_extensions(extensions):
    c_num = 0
    for extension in extensions:
        # if first source file with extension *.c or *.cpp exists
        # it is cythonised or pure c/c++ extension:
        sfile = extension.sources[0]
        path, ext = os.path.splitext(sfile)
        if os.path.exists(path + ".c") or os.path.exists(path + ".cpp"):
            c_num += 1
    return c_num


def cythonize_extensions(extensions):
    try:
        from Cython.Build import cythonize

        return cythonize(extensions, language_level="3")
    except ImportError:
        warnings.warn(
            """WARNING: cython required to generate fast c code is not found on this system.
Only slow pure python alternative functions will be available.
To use fast implementation of some functions writen in cython either:
a) install cython and re-run the installation,
b) try alternative source distribution containing cythonized C versions of fast code,
c) use binary distribution (i.e. wheels, egg)."""
        )
        return []


def no_cythonize(extensions):
    for extension in extensions:
        sources = []
        for sfile in extension.sources:
            path, ext = os.path.splitext(sfile)
            if ext in (".pyx", ".py"):
                if extension.language == "c++":
                    ext = ".cpp"
                else:
                    ext = ".c"
                sfile = path + ext
            sources.append(sfile)
        extension.sources[:] = sources
    return extensions


# to cythonize, or not to cythonize... :
if len(raw_extensions) > count_c_extensions(raw_extensions):
    extensions = cythonize_extensions(raw_extensions)
else:
    extensions = no_cythonize(raw_extensions)

if os.environ.get("DISABLE_C_EXTENTIONS"):
    # Explicitly disable
    extensions = []
else:
    # to compile or not to compile... depends if compiler is present:
    compiler = distutils.ccompiler.new_compiler()
    assert isinstance(compiler, distutils.ccompiler.CCompiler)
    distutils.sysconfig.customize_compiler(compiler)
    try:
        compiler.compile(
            [os.path.join(setup_path, "rsciio", "tests", "test_compilers.c")]
        )
    except (CompileError, DistutilsPlatformError):
        warnings.warn(
            """WARNING: C compiler can't be found.
    Only slow pure python alternative functions will be available.
    To use fast implementation of some functions writen in cython/c either:
    a) check that you have compiler (EXACTLY SAME as your python
    distribution was compiled with) installed,
    b) use binary distribution of hyperspy (i.e. wheels, egg, (only osx and win)).
    Installation will continue in 5 sec..."""
        )
        extensions = []
        from time import sleep

        sleep(5)  # wait 5 secs for user to notice the message


class Recythonize(Command):

    """cythonize all extensions"""

    description = "(re-)cythonize all changed cython extensions"

    user_options = []

    def initialize_options(self):
        """init options"""
        pass

    def finalize_options(self):
        """finalize options"""
        pass

    def run(self):
        # if there is no cython it is supposed to fail:
        from Cython.Build import cythonize

        global raw_extensions
        global extensions
        cythonize(extensions, language_level="3")


setup(
    ext_modules=extensions,
    cmdclass={
        "recythonize": Recythonize,
    },
)