cpython/Lib/distutils/sysconfig.py

"""Provide access to Python's configuration information.  The specific
configuration variables available depend heavily on the platform and
configuration.  The values may be retrieved using
get_config_var(name), and the list of variables is available via
get_config_vars().keys().  Additional convenience functions are also
available.

Written by:   Fred L. Drake, Jr.
Email:        <fdrake@acm.org>
"""

import os
import re
import sys
import warnings

from functools import partial

from .errors import DistutilsPlatformError

from sysconfig import (
    _PREFIX as PREFIX,
    _BASE_PREFIX as BASE_PREFIX,
    _EXEC_PREFIX as EXEC_PREFIX,
    _BASE_EXEC_PREFIX as BASE_EXEC_PREFIX,
    _PROJECT_BASE as project_base,
    _PYTHON_BUILD as python_build,
    _init_posix as sysconfig_init_posix,
    parse_config_h as sysconfig_parse_config_h,

    _init_non_posix,
    _is_python_source_dir,
    _sys_home,

    _variable_rx,
    _findvar1_rx,
    _findvar2_rx,

    expand_makefile_vars,
    is_python_build,
    get_config_h_filename,
    get_config_var,
    get_config_vars,
    get_makefile_filename,
    get_python_version,
)

# This is better than
# from sysconfig import _CONFIG_VARS as _config_vars
# because it makes sure that the global dictionary is initialized
# which might not be true in the time of import.
_config_vars = get_config_vars()

if os.name == "nt":
    from sysconfig import _fix_pcbuild

warnings.warn(
    'The distutils.sysconfig module is deprecated, use sysconfig instead',
    DeprecationWarning,
    stacklevel=2
)


# Following functions are the same as in sysconfig but with different API
def parse_config_h(fp, g=None):
    return sysconfig_parse_config_h(fp, vars=g)


_python_build = partial(is_python_build, check_home=True)
_init_posix = partial(sysconfig_init_posix, _config_vars)
_init_nt = partial(_init_non_posix, _config_vars)


# Similar function is also implemented in sysconfig as _parse_makefile
# but without the parsing capabilities of distutils.text_file.TextFile.
def parse_makefile(fn, g=None):
    """Parse a Makefile-style file.
    A dictionary containing name/value pairs is returned.  If an
    optional dictionary is passed in as the second argument, it is
    used instead of a new dictionary.
    """
    from distutils.text_file import TextFile
    fp = TextFile(fn, strip_comments=1, skip_blanks=1, join_lines=1, errors="surrogateescape")

    if g is None:
        g = {}
    done = {}
    notdone = {}

    while True:
        line = fp.readline()
        if line is None: # eof
            break
        m = re.match(_variable_rx, line)
        if m:
            n, v = m.group(1, 2)
            v = v.strip()
            # `$$' is a literal `$' in make
            tmpv = v.replace('$$', '')

            if "$" in tmpv:
                notdone[n] = v
            else:
                try:
                    v = int(v)
                except ValueError:
                    # insert literal `$'
                    done[n] = v.replace('$$', '$')
                else:
                    done[n] = v

    # Variables with a 'PY_' prefix in the makefile. These need to
    # be made available without that prefix through sysconfig.
    # Special care is needed to ensure that variable expansion works, even
    # if the expansion uses the name without a prefix.
    renamed_variables = ('CFLAGS', 'LDFLAGS', 'CPPFLAGS')

    # do variable interpolation here
    while notdone:
        for name in list(notdone):
            value = notdone[name]
            m = re.search(_findvar1_rx, value) or re.search(_findvar2_rx, value)
            if m:
                n = m.group(1)
                found = True
                if n in done:
                    item = str(done[n])
                elif n in notdone:
                    # get it on a subsequent round
                    found = False
                elif n in os.environ:
                    # do it like make: fall back to environment
                    item = os.environ[n]

                elif n in renamed_variables:
                    if name.startswith('PY_') and name[3:] in renamed_variables:
                        item = ""

                    elif 'PY_' + n in notdone:
                        found = False

                    else:
                        item = str(done['PY_' + n])
                else:
                    done[n] = item = ""
                if found:
                    after = value[m.end():]
                    value = value[:m.start()] + item + after
                    if "$" in after:
                        notdone[name] = value
                    else:
                        try: value = int(value)
                        except ValueError:
                            done[name] = value.strip()
                        else:
                            done[name] = value
                        del notdone[name]

                        if name.startswith('PY_') \
                            and name[3:] in renamed_variables:

                            name = name[3:]
                            if name not in done:
                                done[name] = value
            else:
                # bogus variable reference; just drop it since we can't deal
                del notdone[name]

    fp.close()

    # strip spurious spaces
    for k, v in done.items():
        if isinstance(v, str):
            done[k] = v.strip()

    # save the results in the global dictionary
    g.update(done)
    return g


# Following functions are deprecated together with this module and they
# have no direct replacement

# Calculate the build qualifier flags if they are defined.  Adding the flags
# to the include and lib directories only makes sense for an installation, not
# an in-source build.
build_flags = ''
try:
    if not python_build:
        build_flags = sys.abiflags
except AttributeError:
    # It's not a configure-based build, so the sys module doesn't have
    # this attribute, which is fine.
    pass


def customize_compiler(compiler):
    """Do any platform-specific customization of a CCompiler instance.

    Mainly needed on Unix, so we can plug in the information that
    varies across Unices and is stored in Python's Makefile.
    """
    if compiler.compiler_type == "unix":
        if sys.platform == "darwin":
            # Perform first-time customization of compiler-related
            # config vars on OS X now that we know we need a compiler.
            # This is primarily to support Pythons from binary
            # installers.  The kind and paths to build tools on
            # the user system may vary significantly from the system
            # that Python itself was built on.  Also the user OS
            # version and build tools may not support the same set
            # of CPU architectures for universal builds.
            if not _config_vars.get('CUSTOMIZED_OSX_COMPILER'):
                import _osx_support
                _osx_support.customize_compiler(_config_vars)
                _config_vars['CUSTOMIZED_OSX_COMPILER'] = 'True'

        (cc, cxx, cflags, ccshared, ldshared, shlib_suffix, ar, ar_flags) = \
            get_config_vars('CC', 'CXX', 'CFLAGS',
                            'CCSHARED', 'LDSHARED', 'SHLIB_SUFFIX', 'AR', 'ARFLAGS')

        if 'CC' in os.environ:
            newcc = os.environ['CC']
            if (sys.platform == 'darwin'
                    and 'LDSHARED' not in os.environ
                    and ldshared.startswith(cc)):
                # On OS X, if CC is overridden, use that as the default
                #       command for LDSHARED as well
                ldshared = newcc + ldshared[len(cc):]
            cc = newcc
        if 'CXX' in os.environ:
            cxx = os.environ['CXX']
        if 'LDSHARED' in os.environ:
            ldshared = os.environ['LDSHARED']
        if 'CPP' in os.environ:
            cpp = os.environ['CPP']
        else:
            cpp = cc + " -E"           # not always
        if 'LDFLAGS' in os.environ:
            ldshared = ldshared + ' ' + os.environ['LDFLAGS']
        if 'CFLAGS' in os.environ:
            cflags = cflags + ' ' + os.environ['CFLAGS']
            ldshared = ldshared + ' ' + os.environ['CFLAGS']
        if 'CPPFLAGS' in os.environ:
            cpp = cpp + ' ' + os.environ['CPPFLAGS']
            cflags = cflags + ' ' + os.environ['CPPFLAGS']
            ldshared = ldshared + ' ' + os.environ['CPPFLAGS']
        if 'AR' in os.environ:
            ar = os.environ['AR']
        if 'ARFLAGS' in os.environ:
            archiver = ar + ' ' + os.environ['ARFLAGS']
        else:
            archiver = ar + ' ' + ar_flags

        cc_cmd = cc + ' ' + cflags
        compiler.set_executables(
            preprocessor=cpp,
            compiler=cc_cmd,
            compiler_so=cc_cmd + ' ' + ccshared,
            compiler_cxx=cxx,
            linker_so=ldshared,
            linker_exe=cc,
            archiver=archiver)

        compiler.shared_lib_extension = shlib_suffix


def get_python_inc(plat_specific=0, prefix=None):
    """Return the directory containing installed Python header files.

    If 'plat_specific' is false (the default), this is the path to the
    non-platform-specific header files, i.e. Python.h and so on;
    otherwise, this is the path to platform-specific header files
    (namely pyconfig.h).

    If 'prefix' is supplied, use it instead of sys.base_prefix or
    sys.base_exec_prefix -- i.e., ignore 'plat_specific'.
    """
    if prefix is None:
        prefix = plat_specific and BASE_EXEC_PREFIX or BASE_PREFIX
    if os.name == "posix":
        if python_build:
            # Assume the executable is in the build directory.  The
            # pyconfig.h file should be in the same directory.  Since
            # the build directory may not be the source directory, we
            # must use "srcdir" from the makefile to find the "Include"
            # directory.
            if plat_specific:
                return _sys_home or project_base
            else:
                incdir = os.path.join(get_config_var('srcdir'), 'Include')
                return os.path.normpath(incdir)
        python_dir = 'python' + get_python_version() + build_flags
        return os.path.join(prefix, "include", python_dir)
    elif os.name == "nt":
        if python_build:
            # Include both the include and PC dir to ensure we can find
            # pyconfig.h
            return (os.path.join(prefix, "include") + os.path.pathsep +
                    os.path.join(prefix, "PC"))
        return os.path.join(prefix, "include")
    else:
        raise DistutilsPlatformError(
            "I don't know where Python installs its C header files "
            "on platform '%s'" % os.name)


def get_python_lib(plat_specific=0, standard_lib=0, prefix=None):
    """Return the directory containing the Python library (standard or
    site additions).

    If 'plat_specific' is true, return the directory containing
    platform-specific modules, i.e. any module from a non-pure-Python
    module distribution; otherwise, return the platform-shared library
    directory.  If 'standard_lib' is true, return the directory
    containing standard Python library modules; otherwise, return the
    directory for site-specific modules.

    If 'prefix' is supplied, use it instead of sys.base_prefix or
    sys.base_exec_prefix -- i.e., ignore 'plat_specific'.
    """
    if prefix is None:
        if standard_lib:
            prefix = plat_specific and BASE_EXEC_PREFIX or BASE_PREFIX
        else:
            prefix = plat_specific and EXEC_PREFIX or PREFIX

    if os.name == "posix":
        if plat_specific or standard_lib:
            # Platform-specific modules (any module from a non-pure-Python
            # module distribution) or standard Python library modules.
            libdir = sys.platlibdir
        else:
            # Pure Python
            libdir = "lib"
        libpython = os.path.join(prefix, libdir,
                                 "python" + get_python_version())
        if standard_lib:
            return libpython
        else:
            return os.path.join(libpython, "site-packages")
    elif os.name == "nt":
        if standard_lib:
            return os.path.join(prefix, "Lib")
        else:
            return os.path.join(prefix, "Lib", "site-packages")
    else:
        raise DistutilsPlatformError(
            "I don't know where Python installs its library "
            "on platform '%s'" % os.name)