aksetup_helper.py

import setuptools  # noqa
from setuptools import Extension
import sys
from setuptools.command.build_ext import (  # noqa: N812
        build_ext as BaseBuildExtCommand)


def count_down_delay(delay):
    from time import sleep
    while delay:
        sys.stdout.write("Continuing in %d seconds...   \r" % delay)
        sys.stdout.flush()
        delay -= 1
        sleep(1)
    print("")


DASH_SEPARATOR = 75 * "-"


def setup(*args, **kwargs):
    from setuptools import setup
    try:
        setup(*args, **kwargs)
    except KeyboardInterrupt:
        raise
    except SystemExit:
        raise
    except Exception:
        print(DASH_SEPARATOR)
        print("Sorry, your build failed. Try rerunning configure.py with "
                "different options.")
        print(DASH_SEPARATOR)
        raise


def get_numpy_incpath():
    from imp import find_module
    # avoid actually importing numpy, it screws up distutils
    file, pathname, descr = find_module("numpy")
    from os.path import join
    return join(pathname, "core", "include")


class NumpyExtension(Extension):
    # nicked from
    # http://mail.python.org/pipermail/distutils-sig/2007-September/008253.html
    # solution by Michael Hoffmann
    def __init__(self, *args, **kwargs):
        Extension.__init__(self, *args, **kwargs)
        self._include_dirs = self.include_dirs
        del self.include_dirs  # restore overwritten property

    def get_additional_include_dirs(self):
        return [get_numpy_incpath()]

    def get_include_dirs(self):
        return self._include_dirs + self.get_additional_include_dirs()

    def set_include_dirs(self, value):
        self._include_dirs = value

    def del_include_dirs(self):
        pass

    include_dirs = property(get_include_dirs, set_include_dirs, del_include_dirs)


class ExtensionUsingNumpy(Extension):
    """Unlike :class:`NumpyExtension`, this class does not require numpy to be
    importable upon extension module creation, allowing ``setup_requires=["numpy"]``
    to work. On the other hand, it requires the use of::

        setup(...,
            cmdclass={'build_ext': NumpyBuildExtCommand})

    or

        setup(...,
            cmdclass={'build_ext': PybindBuildExtCommand})
    """


class NumpyBuildExtCommand(BaseBuildExtCommand):
    def build_extension(self, extension):
        # We add the numpy include dir right before building the
        # extension, in order to avoid having to import numpy when
        # the setup script is imported, which would prevent
        # installation before manual installation of numpy.
        if isinstance(extension, ExtensionUsingNumpy):
            numpy_incpath = get_numpy_incpath()
            if numpy_incpath not in extension.include_dirs:
                extension.include_dirs.append(numpy_incpath)

        BaseBuildExtCommand.build_extension(self, extension)


# {{{ tools

def flatten(lst):
    """For an iterable of sub-iterables, generate each member of each
    sub-iterable in turn, i.e. a flattened version of that super-iterable.

    Example: Turn [[a,b,c],[d,e,f]] into [a,b,c,d,e,f].
    """
    for sublist in lst:
        for j in sublist:
            yield j


def humanize(sym_str):
    words = sym_str.lower().replace("_", " ").split(" ")
    return " ".join([word.capitalize() for word in words])

# }}}


# {{{ siteconf handling

def get_config(schema=None, warn_about_no_config=True):
    if schema is None:
        from setup import get_config_schema
        schema = get_config_schema()

    if (not schema.have_config() and not schema.have_global_config()
            and warn_about_no_config):
        print("*************************************************************")
        print("*** I have detected that you have not run configure.py.")
        print("*************************************************************")
        print("*** Additionally, no global config files were found.")
        print("*** I will go ahead with the default configuration.")
        print("*** In all likelihood, this will not work out.")
        print("*** ")
        print("*** See README_SETUP.txt for more information.")
        print("*** ")
        print("*** If the build does fail, just re-run configure.py with the")
        print("*** correct arguments, and then retry. Good luck!")
        print("*************************************************************")
        print("*** HIT Ctrl-C NOW IF THIS IS NOT WHAT YOU WANT")
        print("*************************************************************")

        count_down_delay(delay=10)

    config = expand_options(schema.read_config())
    schema.update_config_from_and_modify_command_line(config, sys.argv)
    return config


def hack_distutils(debug=False, fast_link=True, what_opt=3):
    # hack distutils.sysconfig to eliminate debug flags
    # stolen from mpi4py

    def remove_prefixes(optlist, bad_prefixes):
        for bad_prefix in bad_prefixes:
            for i, flag in enumerate(optlist):
                if flag.startswith(bad_prefix):
                    optlist.pop(i)
                    break
        return optlist

    if not sys.platform.lower().startswith("win"):
        from distutils import sysconfig

        cvars = sysconfig.get_config_vars()

        bad_prefixes = ['-g', '-O', '-Wstrict-prototypes', '-DNDEBUG']

        cflags = cvars.get("OPT")
        if cflags:
            cflags = remove_prefixes(cflags.split(), bad_prefixes)
            if debug:
                cflags.append("-g")
            else:
                if what_opt is None:
                    pass
                else:
                    cflags.append("-O%s" % what_opt)
                    cflags.append("-DNDEBUG")

            cvars["OPT"] = str.join(' ', cflags)

        cflags = cvars.get("CONFIGURE_CFLAGS")
        if cflags:
            cflags = remove_prefixes(cflags.split(), bad_prefixes)
            cvars["CONFIGURE_CFLAGS"] = str.join(' ', cflags)

        if "BASECFLAGS" in cvars:
            cvars["CFLAGS"] = cvars["BASECFLAGS"] + " " + cvars.get("OPT", "")
        else:
            assert "CFLAGS" in cvars

        if fast_link:
            for varname in ["LDSHARED", "BLDSHARED"]:
                ldsharedflags = cvars.get(varname)
                if ldsharedflags:
                    ldsharedflags = remove_prefixes(ldsharedflags.split(),
                            ['-Wl,-O'])
                    cvars[varname] = str.join(' ', ldsharedflags)

# }}}


# {{{ configure guts

def default_or(a, b):
    if a is None:
        return b
    else:
        return a


def expand_str(s, options):
    import re

    def my_repl(match):
        sym = match.group(1)
        try:
            repl = options[sym]
        except KeyError:
            from os import environ
            repl = environ[sym]

        return expand_str(repl, options)

    return re.subn(r"\$\{([a-zA-Z0-9_]+)\}", my_repl, s)[0]


def expand_value(v, options):
    if isinstance(v, str):
        return expand_str(v, options)
    elif isinstance(v, list):
        result = []
        for i in v:
            try:
                exp_i = expand_value(i, options)
            except Exception:
                pass
            else:
                result.append(exp_i)

        return result
    else:
        return v


def expand_options(options):
    return dict(
            (k, expand_value(v, options)) for k, v in options.items())


class ConfigSchema:
    def __init__(self, options, conf_file="siteconf.py", conf_dir="."):
        self.optdict = dict((opt.name, opt) for opt in options)
        self.options = options
        self.conf_dir = conf_dir
        self.conf_file = conf_file

        from os.path import expanduser
        self.user_conf_file = expanduser("~/.aksetup-defaults.py")

        if not sys.platform.lower().startswith("win"):
            self.global_conf_file = "/etc/aksetup-defaults.py"
        else:
            self.global_conf_file = None

    def get_conf_file(self):
        import os
        return os.path.join(self.conf_dir, self.conf_file)

    def set_conf_dir(self, conf_dir):
        self.conf_dir = conf_dir

    def get_default_config(self):
        return dict((opt.name, opt.default) for opt in self.options)

    def read_config_from_pyfile(self, filename):
        result = {}
        filevars = {}
        infile = open(filename, "r")
        try:
            contents = infile.read()
        finally:
            infile.close()

        exec(compile(contents, filename, "exec"), filevars)

        for key, value in filevars.items():
            if key in self.optdict:
                result[key] = value

        return result

    def update_conf_file(self, filename, config):
        result = {}
        filevars = {}

        try:
            exec(compile(open(filename, "r").read(), filename, "exec"), filevars)
        except IOError:
            pass

        if "__builtins__" in filevars:
            del filevars["__builtins__"]

        for key, value in config.items():
            if value is not None:
                filevars[key] = value

        keys = list(filevars.keys())
        keys.sort()

        outf = open(filename, "w")
        for key in keys:
            outf.write("%s = %s\n" % (key, repr(filevars[key])))
        outf.close()

        return result

    def update_user_config(self, config):
        self.update_conf_file(self.user_conf_file, config)

    def update_global_config(self, config):
        if self.global_conf_file is not None:
            self.update_conf_file(self.global_conf_file, config)

    def get_default_config_with_files(self):
        result = self.get_default_config()

        import os

        confignames = []
        if self.global_conf_file is not None:
            confignames.append(self.global_conf_file)
        confignames.append(self.user_conf_file)

        for fn in confignames:
            if os.access(fn, os.R_OK):
                result.update(self.read_config_from_pyfile(fn))

        return result

    def have_global_config(self):
        import os
        result = os.access(self.user_conf_file, os.R_OK)

        if self.global_conf_file is not None:
            result = result or os.access(self.global_conf_file, os.R_OK)

        return result

    def have_config(self):
        import os
        return os.access(self.get_conf_file(), os.R_OK)

    def update_from_python_snippet(self, config, py_snippet, filename):
        filevars = {}
        exec(compile(py_snippet, filename, "exec"), filevars)

        for key, value in filevars.items():
            if key in self.optdict:
                config[key] = value
            elif key == "__builtins__":
                pass
            else:
                raise KeyError("invalid config key in %s: %s" % (
                        filename, key))

    def update_config_from_and_modify_command_line(self, config, argv):
        cfg_prefix = "--conf:"

        i = 0
        while i < len(argv):
            arg = argv[i]

            if arg.startswith(cfg_prefix):
                del argv[i]
                self.update_from_python_snippet(
                        config, arg[len(cfg_prefix):], "<command line>")
            else:
                i += 1

        return config

    def read_config(self):
        import os
        cfile = self.get_conf_file()

        result = self.get_default_config_with_files()
        if os.access(cfile, os.R_OK):
            with open(cfile, "r") as inf:
                py_snippet = inf.read()
            self.update_from_python_snippet(result, py_snippet, cfile)

        return result

    def add_to_configparser(self, parser, def_config=None):
        if def_config is None:
            def_config = self.get_default_config_with_files()

        for opt in self.options:
            default = default_or(def_config.get(opt.name), opt.default)
            opt.add_to_configparser(parser, default)

    def get_from_configparser(self, options):
        result = {}
        for opt in self.options:
            result[opt.name] = opt.take_from_configparser(options)
        return result

    def write_config(self, config):
        outf = open(self.get_conf_file(), "w")
        for opt in self.options:
            value = config[opt.name]
            if value is not None:
                outf.write("%s = %s\n" % (opt.name, repr(config[opt.name])))
        outf.close()

    def make_substitutions(self, config):
        return dict((opt.name, opt.value_to_str(config[opt.name]))
                for opt in self.options)


class Option(object):
    def __init__(self, name, default=None, help=None):
        self.name = name
        self.default = default
        self.help = help

    def as_option(self):
        return self.name.lower().replace("_", "-")

    def metavar(self):
        last_underscore = self.name.rfind("_")
        return self.name[last_underscore+1:]

    def get_help(self, default):
        result = self.help
        if self.default:
            result += " (default: %s)" % self.value_to_str(
                    default_or(default, self.default))
        return result

    def value_to_str(self, default):
        return default

    def add_to_configparser(self, parser, default=None):
        default = default_or(default, self.default)
        default_str = self.value_to_str(default)
        parser.add_option(
            "--" + self.as_option(), dest=self.name,
            default=default_str,
            metavar=self.metavar(), help=self.get_help(default))

    def take_from_configparser(self, options):
        return getattr(options, self.name)


class Switch(Option):
    def add_to_configparser(self, parser, default=None):
        if not isinstance(self.default, bool):
            raise ValueError("Switch options must have a default")

        if default is None:
            default = self.default

        option_name = self.as_option()

        if default:
            option_name = "no-" + option_name
            action = "store_false"
        else:
            action = "store_true"

        parser.add_option(
            "--" + option_name,
            dest=self.name,
            help=self.get_help(default),
            default=default,
            action=action)


class StringListOption(Option):
    def value_to_str(self, default):
        if default is None:
            return None

        return ",".join([str(el).replace(",", r"\,") for el in default])

    def get_help(self, default):
        return Option.get_help(self, default) + " (several ok)"

    def take_from_configparser(self, options):
        opt = getattr(options, self.name)
        if opt is None:
            return None
        else:
            if opt:
                import re
                sep = re.compile(r"(?<!\\),")
                result = sep.split(opt)
                result = [i.replace(r"\,", ",") for i in result]
                return result
            else:
                return []


class IncludeDir(StringListOption):
    def __init__(self, lib_name, default=None, human_name=None, help=None):
        StringListOption.__init__(self, "%s_INC_DIR" % lib_name, default,
                help=help or ("Include directories for %s"
                % (human_name or humanize(lib_name))))


class LibraryDir(StringListOption):
    def __init__(self, lib_name, default=None, human_name=None, help=None):
        StringListOption.__init__(self, "%s_LIB_DIR" % lib_name, default,
                help=help or ("Library directories for %s"
                % (human_name or humanize(lib_name))))


class Libraries(StringListOption):
    def __init__(self, lib_name, default=None, human_name=None, help=None):
        StringListOption.__init__(self, "%s_LIBNAME" % lib_name, default,
                help=help or ("Library names for %s (without lib or .so)"
                % (human_name or humanize(lib_name))))

# }}}


# {{{ configure options for specific software

class BoostLibraries(Libraries):
    def __init__(self, lib_base_name, default_lib_name=None):
        if default_lib_name is None:
            if lib_base_name == "python":
                default_lib_name = "boost_python-py%d%d" % sys.version_info[:2]
            else:
                default_lib_name = "boost_%s" % lib_base_name

        Libraries.__init__(self, "BOOST_%s" % lib_base_name.upper(),
                [default_lib_name],
                help="Library names for Boost C++ %s library (without lib or .so)"
                % humanize(lib_base_name))


def set_up_shipped_boost_if_requested(project_name, conf, source_path=None,
        boost_chrono=False):
    """Set up the package to use a shipped version of Boost.

    Return a tuple of a list of extra C files to build and extra
    defines to be used.

    :arg boost_chrono: one of *False* and ``"header_only"``
        (only relevant in shipped mode)
    """
    from os.path import exists

    if source_path is None:
        source_path = "bpl-subset/bpl_subset"

    if conf["USE_SHIPPED_BOOST"]:
        if not exists("%s/boost/version.hpp" % source_path):
            print(DASH_SEPARATOR)
            print("The shipped Boost library was not found, but "
                    "USE_SHIPPED_BOOST is True.")
            print("(The files should be under %s/.)" % source_path)
            print(DASH_SEPARATOR)
            print("If you got this package from git, you probably want to do")
            print("")
            print(" $ git submodule update --init")
            print("")
            print("to fetch what you are presently missing. If you got this from")
            print("a distributed package on the net, that package is broken and")
            print("should be fixed. For now, I will turn off 'USE_SHIPPED_BOOST'")
            print("to try and see if the build succeeds that way, but in the long")
            print("run you might want to either get the missing bits or turn")
            print("'USE_SHIPPED_BOOST' off.")
            print(DASH_SEPARATOR)
            conf["USE_SHIPPED_BOOST"] = False

            count_down_delay(delay=10)

    if conf["USE_SHIPPED_BOOST"]:
        conf["BOOST_INC_DIR"] = [source_path]
        conf["BOOST_LIB_DIR"] = []
        conf["BOOST_PYTHON_LIBNAME"] = []
        conf["BOOST_THREAD_LIBNAME"] = []

        from glob import glob
        source_files = (glob(source_path + "/libs/*/*/*/*.cpp")
                + glob(source_path + "/libs/*/*/*.cpp")
                + glob(source_path + "/libs/*/*.cpp"))

        # make sure next line succeeds even on Windows
        source_files = [f.replace("\\", "/") for f in source_files]

        source_files = [f for f in source_files
                if not f.startswith(source_path + "/libs/thread/src")]

        if sys.platform == "win32":
            source_files += glob(
                    source_path + "/libs/thread/src/win32/*.cpp")
            source_files += glob(
                    source_path + "/libs/thread/src/tss_null.cpp")
        else:
            source_files += glob(
                    source_path + "/libs/thread/src/pthread/*.cpp")

        source_files = [f for f in source_files
                if not f.endswith("once_atomic.cpp")]

        from os.path import isdir
        main_boost_inc = source_path + "/boost"
        bpl_project_boost_inc = source_path + "/%sboost" % project_name

        if not isdir(bpl_project_boost_inc):
            try:
                from os import symlink
                symlink("boost", bpl_project_boost_inc)
            except (ImportError, OSError):
                from shutil import copytree
                print("Copying files, hang on... (do not interrupt)")
                copytree(main_boost_inc, bpl_project_boost_inc)

        defines = {
                # do not pick up libboost link dependency on windows
                "BOOST_ALL_NO_LIB": 1,
                "BOOST_THREAD_BUILD_DLL": 1,

                "BOOST_MULTI_INDEX_DISABLE_SERIALIZATION": 1,
                "BOOST_PYTHON_SOURCE": 1,
                "boost": '%sboost' % project_name,
                }

        if boost_chrono is False:
            defines["BOOST_THREAD_DONT_USE_CHRONO"] = 1
        elif boost_chrono == "header_only":
            defines["BOOST_CHRONO_HEADER_ONLY"] = 1
        else:
            raise ValueError("invalid value of 'boost_chrono'")

        return (source_files, defines)
    else:
        return [], {}


def make_boost_base_options():
    return [
        IncludeDir("BOOST", []),
        LibraryDir("BOOST", []),
        Option("BOOST_COMPILER", default="gcc43",
            help="The compiler with which Boost C++ was compiled, e.g. gcc43"),
        ]

# }}}


# {{{ configure frontend

def configure_frontend():
    from optparse import OptionParser

    from setup import get_config_schema
    schema = get_config_schema()
    if schema.have_config():
        print("************************************************************")
        print("*** I have detected that you have already run configure.")
        print("*** I'm taking the configured values as defaults for this")
        print("*** configure run. If you don't want this, delete the file")
        print("*** %s." % schema.get_conf_file())
        print("************************************************************")

    description = "generate a configuration file for this software package"
    parser = OptionParser(description=description)
    parser.add_option(
            "--python-exe", dest="python_exe", default=sys.executable,
            help="Which Python interpreter to use", metavar="PATH")

    parser.add_option("--prefix", default=None,
            help="Ignored")
    parser.add_option("--enable-shared", help="Ignored", action="store_false")
    parser.add_option("--disable-static", help="Ignored", action="store_false")
    parser.add_option("--update-user",
            help="Update user config file (%s)" % schema.user_conf_file,
            action="store_true")
    parser.add_option("--update-global",
            help="Update global config file (%s)" % schema.global_conf_file,
            action="store_true")

    schema.add_to_configparser(parser, schema.read_config())

    options, args = parser.parse_args()

    config = schema.get_from_configparser(options)
    schema.write_config(config)

    if options.update_user:
        schema.update_user_config(config)

    if options.update_global:
        schema.update_global_config(config)

    import os
    if os.access("Makefile.in", os.F_OK):
        substs = schema.make_substitutions(config)
        substs["PYTHON_EXE"] = options.python_exe

        substitute(substs, "Makefile")

# }}}


def substitute(substitutions, fname):
    import re
    var_re = re.compile(r"\$\{([A-Za-z_0-9]+)\}")
    string_var_re = re.compile(r"\$str\{([A-Za-z_0-9]+)\}")

    fname_in = fname+".in"
    with open(fname_in, "r") as inf:
        lines = inf.readlines()

    new_lines = []
    for line in lines:
        made_change = True
        while made_change:
            made_change = False
            match = var_re.search(line)
            if match:
                varname = match.group(1)
                line = (
                        line[:match.start()]
                        + str(substitutions[varname])
                        + line[match.end():])
                made_change = True

            match = string_var_re.search(line)
            if match:
                varname = match.group(1)
                subst = substitutions[varname]
                if subst is None:
                    subst = ""
                else:
                    subst = '"%s"' % subst

                line = line[:match.start()] + subst + line[match.end():]
                made_change = True
        new_lines.append(line)
    new_lines.insert(1, "# DO NOT EDIT THIS FILE -- "
            "it was generated by configure.py\n")
    new_lines.insert(2, "# %s\n" % (" ".join(sys.argv)))
    with open(fname, "w") as outf:
        outf.write("".join(new_lines))

    from os import stat, chmod
    infile_stat_res = stat(fname_in)
    chmod(fname, infile_stat_res.st_mode)


# {{{ git bits

def _run_git_command(cmd):
    git_error = None
    from subprocess import Popen, PIPE
    stdout = None
    try:
        popen = Popen(["git"] + cmd, stdout=PIPE)
        stdout, stderr = popen.communicate()
        if popen.returncode != 0:
            git_error = "git returned error code %d: %s" % (popen.returncode, stderr)
    except OSError:
        git_error = "(OS error, likely git not found)"

    if git_error is not None:
        print(DASH_SEPARATOR)
        print("Trouble invoking git")
        print(DASH_SEPARATOR)
        print("The package directory appears to be a git repository, but I could")
        print("not invoke git to check whether my submodules are up to date.")
        print("")
        print("The error was:")
        print(git_error)
        print("Hit Ctrl-C now if you'd like to think about the situation.")
        print(DASH_SEPARATOR)
        count_down_delay(delay=0)
    if stdout:
        return stdout.decode("utf-8"), git_error
    else:
        return '', "(subprocess call to git did not succeed)"


def check_git_submodules():
    from os.path import isdir
    if not isdir(".git"):
        # not a git repository
        return
    if isdir("../.repo"):
        # assume repo is in charge and bail
        return

    stdout, git_error = _run_git_command(["submodule", "status"])
    if git_error is not None:
        return

    pkg_warnings = []

    lines = stdout.split("\n")
    for l in lines:
        if not l.strip():
            continue

        status = l[0]
        sha, package = l[1:].split(" ", 1)

        if package == "bpl-subset" or (
                package.startswith("boost") and package.endswith("subset")):
            # treated separately
            continue

        if status == "+":
            pkg_warnings.append("version of '%s' is not what this "
                    "outer package wants" % package)
        elif status == "-":
            pkg_warnings.append("subpackage '%s' is not initialized"
                    % package)
        elif status == " ":
            pass
        else:
            pkg_warnings.append("subpackage '%s' has unrecognized status '%s'"
                    % package)

    if pkg_warnings:
            print(DASH_SEPARATOR)
            print("git submodules are not up-to-date or in odd state")
            print(DASH_SEPARATOR)
            print("If this makes no sense, you probably want to say")
            print("")
            print(" $ git submodule update --init")
            print("")
            print("to fetch what you are presently missing and "
                    "move on with your life.")
            print("If you got this from a distributed package on the "
                    "net, that package is")
            print("broken and should be fixed. Please inform whoever "
                    "gave you this package.")
            print("")
            print("These issues were found:")
            for w in pkg_warnings:
                print("  %s" % w)
            print("")
            print("I will try to initialize the submodules for you "
                    "after a short wait.")
            print(DASH_SEPARATOR)
            print("Hit Ctrl-C now if you'd like to think about the situation.")
            print(DASH_SEPARATOR)

            from os.path import exists
            if not exists(".dirty-git-ok"):
                count_down_delay(delay=10)
                stdout, git_error = _run_git_command(
                        ["submodule", "update", "--init"])
                if git_error is None:
                    print(DASH_SEPARATOR)
                    print("git submodules initialized successfully")
                    print(DASH_SEPARATOR)

# }}}


# {{{ pybind11

def check_pybind11():
    try:
        import pybind11  # noqa
    except ImportError:
        print(DASH_SEPARATOR)
        print("Pybind11 is not installed.")
        print(DASH_SEPARATOR)
        print("Very likely, the build process after this message will fail.")
        print("")
        print("Simply press Ctrl+C and type")
        print("python -m pip install pybind11")
        print("to fix this. If you don't, the build will continue ")
        print("in a few seconds.")
        print("")
        print("[1] https://pybind11.readthedocs.io/en/stable/")
        print(DASH_SEPARATOR)

        from aksetup_helper import count_down_delay
        count_down_delay(delay=10)


# {{{ (modified) boilerplate from https://github.com/pybind/python_example/blob/2ed5a68759cd6ff5d2e5992a91f08616ef457b5c/setup.py  # noqa

class get_pybind_include(object):  # noqa: N801
    """Helper class to determine the pybind11 include path

    The purpose of this class is to postpone importing pybind11
    until it is actually installed, so that the ``get_include()``
    method can be invoked. """

    def __init__(self, user=False):
        self.user = user

    def __str__(self):
        import pybind11
        return pybind11.get_include(self.user)


# As of Python 3.6, CCompiler has a `has_flag` method.
# cf http://bugs.python.org/issue26689
def has_flag(compiler, flagname):
    """Return a boolean indicating whether a flag name is supported on
    the specified compiler.
    """
    import tempfile
    with tempfile.NamedTemporaryFile('w', suffix='.cpp', delete=False) as f:
        f.write('int main (int argc, char **argv) { return 0; }')
        fname = f.name
    try:
        compiler.compile([fname], extra_postargs=[flagname])
    except setuptools.distutils.errors.CompileError:
        return False
    return True


def cpp_flag(compiler):
    """Return the -std=c++[11/14] compiler flag.

    The c++14 is preferred over c++11 (when it is available).
    """
    if has_flag(compiler, '-std=gnu++14'):
        return '-std=gnu++14'
    elif has_flag(compiler, '-std=c++14'):
        return '-std=c++14'
    elif has_flag(compiler, '-std=c++11'):
        return '-std=c++11'
    else:
        raise RuntimeError('Unsupported compiler -- at least C++11 support '
                           'is needed!')


class PybindBuildExtCommand(NumpyBuildExtCommand):
    """A custom build extension for adding compiler-specific options."""
    c_opts = {
        'msvc': ['/EHsc'],
        'unix': [],
    }

    def build_extensions(self):
        ct = self.compiler.compiler_type
        opts = self.c_opts.get(ct, [])
        cxx_opts = []

        if ct in ['unix', 'mingw32']:
            opts.append('-DVERSION_INFO="%s"' % self.distribution.get_version())
            cxx_opts.append(cpp_flag(self.compiler))
            if has_flag(self.compiler, '-fvisibility=hidden'):
                opts.append('-fvisibility=hidden')
            if sys.platform == 'darwin':
                if has_flag(self.compiler, '-stdlib=libc++'):
                    opts.append('-stdlib=libc++')
                if has_flag(self.compiler, '-mmacosx-version-min=10.7'):
                    opts.append('-mmacosx-version-min=10.7')
        elif ct == 'msvc':
            opts.append('/DVERSION_INFO=\\"%s\\"' % self.distribution.get_version())
        for ext in self.extensions:
            ext.extra_compile_args = ext.extra_compile_args + opts

        prev__compile = self.compiler._compile

        # -std=... used on C files causes an error on Apple LLVM
        # https://gitlab.tiker.net/inducer/pymetis/-/jobs/102421
        def _compile(obj, src, ext, cc_args, extra_postargs, pp_opts):
            if ext == ".cpp":
                cc_args = cc_args + cxx_opts

            return prev__compile(obj, src, ext, cc_args, extra_postargs, pp_opts)

        self.compiler._compile = _compile

        try:
            NumpyBuildExtCommand.build_extensions(self)
        finally:
            self.compiler._compile = prev__compile

# }}}

# }}}

# vim: foldmethod=marker