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 ?÷     	"""Shared OS X support functions."""

import os
import re
import sys

__all__ = [
    'compiler_fixup',
    'customize_config_vars',
    'customize_compiler',
    'get_platform_osx',
]

# configuration variables that may contain universal build flags,
# like "-arch" or "-isdkroot", that may need customization for
# the user environment
_UNIVERSAL_CONFIG_VARS = ('CFLAGS', 'LDFLAGS', 'CPPFLAGS', 'BASECFLAGS',
                            'BLDSHARED', 'LDSHARED', 'CC', 'CXX',
                            'PY_CFLAGS', 'PY_LDFLAGS', 'PY_CPPFLAGS',
                            'PY_CORE_CFLAGS')

# configuration variables that may contain compiler calls
_COMPILER_CONFIG_VARS = ('BLDSHARED', 'LDSHARED', 'CC', 'CXX')

# prefix added to original configuration variable names
_INITPRE = '_OSX_SUPPORT_INITIAL_'


def _find_executable(executable, path=None):
    """Tries to find 'executable' in the directories listed in 'path'.

    A string listing directories separated by 'os.pathsep'; defaults to
    os.environ['PATH'].  Returns the complete filename or None if not found.
    """
    if path is None:
        path = os.environ['PATH']

    paths = path.split(os.pathsep)
    base, ext = os.path.splitext(executable)

    if (sys.platform == 'win32' or os.name == 'os2') and (ext != '.exe'):
        executable = executable + '.exe'

    if not os.path.isfile(executable):
        for p in paths:
            f = os.path.join(p, executable)
            if os.path.isfile(f):
                # the file exists, we have a shot at spawn working
                return f
        return None
    else:
        return executable


def _read_output(commandstring):
    """Output from succesful command execution or None"""
    # Similar to os.popen(commandstring, "r").read(),
    # but without actually using os.popen because that
    # function is not usable during python bootstrap.
    # tempfile is also not available then.
    import contextlib
    try:
        import tempfile
        fp = tempfile.NamedTemporaryFile()
    except ImportError:
        fp = open("/tmp/_osx_support.%s"%(
            os.getpid(),), "w+b")

    with contextlib.closing(fp) as fp:
        cmd = "%s 2>/dev/null >'%s'" % (commandstring, fp.name)
        return fp.read().decode('utf-8').strip() if not os.system(cmd) else None


def _find_build_tool(toolname):
    """Find a build tool on current path or using xcrun"""
    return (_find_executable(toolname)
                or _read_output("/usr/bin/xcrun -find %s" % (toolname,))
                or ''
            )

_SYSTEM_VERSION = None

def _get_system_version():
    """Return the OS X system version as a string"""
    # Reading this plist is a documented way to get the system
    # version (see the documentation for the Gestalt Manager)
    # We avoid using platform.mac_ver to avoid possible bootstrap issues during
    # the build of Python itself (distutils is used to build standard library
    # extensions).

    global _SYSTEM_VERSION

    if _SYSTEM_VERSION is None:
        _SYSTEM_VERSION = ''
        try:
            f = open('/System/Library/CoreServices/SystemVersion.plist')
        except IOError:
            # We're on a plain darwin box, fall back to the default
            # behaviour.
            pass
        else:
            try:
                m = re.search(r'<key>ProductUserVisibleVersion</key>\s*'
                              r'<string>(.*?)</string>', f.read())
            finally:
                f.close()
            if m is not None:
                _SYSTEM_VERSION = '.'.join(m.group(1).split('.')[:2])
            # else: fall back to the default behaviour

    return _SYSTEM_VERSION

def _remove_original_values(_config_vars):
    """Remove original unmodified values for testing"""
    # This is needed for higher-level cross-platform tests of get_platform.
    for k in list(_config_vars):
        if k.startswith(_INITPRE):
            del _config_vars[k]

def _save_modified_value(_config_vars, cv, newvalue):
    """Save modified and original unmodified value of configuration var"""