text: """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>
  """
  
  __revision__ = "$Id: sysconfig.py 73343 2009-06-11 08:31:17Z tarek.ziade $"
  
  import io
  import os
  import re
  import sys
  
  from .errors import DistutilsPlatformError
  
  # These are needed in a couple of spots, so just compute them once.
  PREFIX = os.path.normpath(sys.prefix)
  EXEC_PREFIX = os.path.normpath(sys.exec_prefix)
  
  # Path to the base directory of the project. On Windows the binary may
  # live in project/PCBuild9.  If we're dealing with an x64 Windows build,
  # it'll live in project/PCbuild/amd64.
  project_base = os.path.dirname(os.path.abspath(sys.executable))
  if os.name == "nt" and "pcbuild" in project_base[-8:].lower():
      project_base = os.path.abspath(os.path.join(project_base, os.path.pardir))
  # PC/VS7.1
  if os.name == "nt" and "\\pc\\v" in project_base[-10:].lower():
      project_base = os.path.abspath(os.path.join(project_base, os.path.pardir,
                                                  os.path.pardir))
  # PC/AMD64
  if os.name == "nt" and "\\pcbuild\\amd64" in project_base[-14:].lower():
      project_base = os.path.abspath(os.path.join(project_base, os.path.pardir,
                                                  os.path.pardir))
  
  # python_build: (Boolean) if true, we're either building Python or
  # building an extension with an un-installed Python, so we use
  # different (hard-wired) directories.
  # Setup.local is available for Makefile builds including VPATH builds,
  # Setup.dist is available on Windows
  def _python_build():
      for fn in ("Setup.dist", "Setup.local"):
          if os.path.isfile(os.path.join(project_base, "Modules", fn)):
              return True
      return False
  python_build = _python_build()
  
  def get_python_version():
      """Return a string containing the major and minor Python version,
      leaving off the patchlevel.  Sample return values could be '1.5'
      or '2.2'.
      """
      return sys.version[:3]
  
  
  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.prefix or
      sys.exec_prefix -- i.e., ignore 'plat_specific'.
      """
      if prefix is None:
          prefix = plat_specific and EXEC_PREFIX or 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.
              base = os.path.dirname(os.path.abspath(sys.executable))
              if plat_specific:
                  return base
              else:
                  incdir = os.path.join(get_config_var('srcdir'), 'Include')
                  return os.path.normpath(incdir)
          return os.path.join(prefix, "include", "python" + get_python_version())
      elif os.name == "nt":
          return os.path.join(prefix, "include")
      elif os.name == "mac":
          if plat_specific:
              return os.path.join(prefix, "Mac", "Include")
          else:
              return os.path.join(prefix, "Include")
      elif os.name == "os2":
          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.prefix or
      sys.exec_prefix -- i.e., ignore 'plat_specific'.
      """
      if prefix is None:
          prefix = plat_specific and EXEC_PREFIX or PREFIX
  
      if os.name == "posix":
          libpython = os.path.join(prefix,
                                   "lib", "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:
              if get_python_version() < "2.2":
                  return prefix
              else:
                  return os.path.join(prefix, "Lib", "site-packages")
      elif os.name == "mac":
          if plat_specific:
              if standard_lib:
                  return os.path.join(prefix, "Lib", "lib-dynload")
              else:
                  return os.path.join(prefix, "Lib", "site-packages")
          else:
              if standard_lib:
                  return os.path.join(prefix, "Lib")
              else:
                  return os.path.join(prefix, "Lib", "site-packages")
      elif os.name == "os2":
          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)
  
  
  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":
          (cc, cxx, opt, cflags, ccshared, ldshared, so_ext, ar, ar_flags) = \
              get_config_vars('CC', 'CXX', 'OPT', 'CFLAGS',
                              'CCSHARED', 'LDSHARED', 'SO', 'AR', 'ARFLAGS')
  
          if 'CC' in os.environ:
              cc = os.environ['CC']
          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 = opt + ' ' + 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 = so_ext
  
  
  def get_config_h_filename():
      """Return full pathname of installed pyconfig.h file."""
      if python_build:
          if os.name == "nt":
              inc_dir = os.path.join(project_base, "PC")
          else:
              inc_dir = project_base
      else:
          inc_dir = get_python_inc(plat_specific=1)
      if get_python_version() < '2.2':
          config_h = 'config.h'
      else:
          # The name of the config.h file changed in 2.2
          config_h = 'pyconfig.h'
      return os.path.join(inc_dir, config_h)
  
  
  def get_makefile_filename():
      """Return full pathname of installed Makefile from the Python build."""
      if python_build:
          return os.path.join(os.path.dirname(sys.executable), "Makefile")
      lib_dir = get_python_lib(plat_specific=1, standard_lib=1)
      return os.path.join(lib_dir, "config", "Makefile")
  
  
  def parse_config_h(fp, g=None):
      """Parse a config.h-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.
      """
      if g is None:
          g = {}
      define_rx = re.compile("#define ([A-Z][A-Za-z0-9_]+) (.*)\n")
      undef_rx = re.compile("/[*] #undef ([A-Z][A-Za-z0-9_]+) [*]/\n")
      #
      while True:
          line = fp.readline()
          if not line:
              break
          m = define_rx.match(line)
          if m:
              n, v = m.group(1, 2)
              try: v = int(v)
              except ValueError: pass
              g[n] = v
          else:
              m = undef_rx.match(line)
              if m:
                  g[m.group(1)] = 0
      return g
  
  
  # Regexes needed for parsing Makefile (and similar syntaxes,
  # like old-style Setup files).
  _variable_rx = re.compile("([a-zA-Z][a-zA-Z0-9_]+)\s*=\s*(.*)")
  _findvar1_rx = re.compile(r"\$\(([A-Za-z][A-Za-z0-9_]*)\)")
  _findvar2_rx = re.compile(r"\${([A-Za-z][A-Za-z0-9_]*)}")
  
  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)
  
      if g is None:
          g = {}
      done = {}
      notdone = {}
  
      while True:
          line = fp.readline()
          if line is None: # eof
              break
          m = _variable_rx.match(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
  
      # do variable interpolation here
      while notdone:
          for name in list(notdone):
              value = notdone[name]
              m = _findvar1_rx.search(value) or _findvar2_rx.search(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]
                  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]
              else:
                  # bogus variable reference; just drop it since we can't deal
                  del notdone[name]
  
      fp.close()
  
      # save the results in the global dictionary
      g.update(done)
      return g
  
  
  def expand_makefile_vars(s, vars):
      """Expand Makefile-style variables -- "${foo}" or "$(foo)" -- in
      'string' according to 'vars' (a dictionary mapping variable names to
      values).  Variables not present in 'vars' are silently expanded to the
      empty string.  The variable values in 'vars' should not contain further
      variable expansions; if 'vars' is the output of 'parse_makefile()',
      you're fine.  Returns a variable-expanded version of 's'.
      """
  
      # This algorithm does multiple expansion, so if vars['foo'] contains
      # "${bar}", it will expand ${foo} to ${bar}, and then expand
      # ${bar}... and so forth.  This is fine as long as 'vars' comes from
      # 'parse_makefile()', which takes care of such expansions eagerly,
      # according to make's variable expansion semantics.
  
      while True:
          m = _findvar1_rx.search(s) or _findvar2_rx.search(s)
          if m:
              (beg, end) = m.span()
              s = s[0:beg] + vars.get(m.group(1)) + s[end:]
          else:
              break
      return s
  
  
  _config_vars = None
  
  def _init_posix():
      """Initialize the module as appropriate for POSIX systems."""
      g = {}
      # load the installed Makefile:
      try:
          filename = get_makefile_filename()
          parse_makefile(filename, g)
      except IOError as msg:
          my_msg = "invalid Python installation: unable to open %s" % filename
          if hasattr(msg, "strerror"):
              my_msg = my_msg + " (%s)" % msg.strerror
  
          raise DistutilsPlatformError(my_msg)
  
      # load the installed pyconfig.h:
      try:
          filename = get_config_h_filename()
          parse_config_h(io.open(filename), g)
      except IOError as msg:
          my_msg = "invalid Python installation: unable to open %s" % filename
          if hasattr(msg, "strerror"):
              my_msg = my_msg + " (%s)" % msg.strerror
  
          raise DistutilsPlatformError(my_msg)
  
      # On MacOSX we need to check the setting of the environment variable
      # MACOSX_DEPLOYMENT_TARGET: configure bases some choices on it so
      # it needs to be compatible.
      # If it isn't set we set it to the configure-time value
      if sys.platform == 'darwin' and 'MACOSX_DEPLOYMENT_TARGET' in g:
          cfg_target = g['MACOSX_DEPLOYMENT_TARGET']
          cur_target = os.getenv('MACOSX_DEPLOYMENT_TARGET', '')
          if cur_target == '':
              cur_target = cfg_target
              os.putenv('MACOSX_DEPLOYMENT_TARGET', cfg_target)
          elif [int(x) for x in cfg_target.split('.')] > [int(x) for x in cur_target.split('.')]:
              my_msg = ('$MACOSX_DEPLOYMENT_TARGET mismatch: now "%s" but "%s" during configure'
                  % (cur_target, cfg_target))
              raise DistutilsPlatformError(my_msg)
  
      # On AIX, there are wrong paths to the linker scripts in the Makefile
      # -- these paths are relative to the Python source, but when installed
      # the scripts are in another directory.
      if python_build:
          g['LDSHARED'] = g['BLDSHARED']
  
      elif get_python_version() < '2.1':
          # The following two branches are for 1.5.2 compatibility.
          if sys.platform == 'aix4':          # what about AIX 3.x ?
              # Linker script is in the config directory, not in Modules as the
              # Makefile says.
              python_lib = get_python_lib(standard_lib=1)
              ld_so_aix = os.path.join(python_lib, 'config', 'ld_so_aix')
              python_exp = os.path.join(python_lib, 'config', 'python.exp')
  
              g['LDSHARED'] = "%s %s -bI:%s" % (ld_so_aix, g['CC'], python_exp)
  
      global _config_vars
      _config_vars = g
  
  
  def _init_nt():
      """Initialize the module as appropriate for NT"""
      g = {}
      # set basic install directories
      g['LIBDEST'] = get_python_lib(plat_specific=0, standard_lib=1)
      g['BINLIBDEST'] = get_python_lib(plat_specific=1, standard_lib=1)
  
      # XXX hmmm.. a normal install puts include files here
      g['INCLUDEPY'] = get_python_inc(plat_specific=0)
  
      g['SO'] = '.pyd'
      g['EXE'] = ".exe"
      g['VERSION'] = get_python_version().replace(".", "")
      g['BINDIR'] = os.path.dirname(os.path.abspath(sys.executable))
  
      global _config_vars
      _config_vars = g
  
  
  def _init_mac():
      """Initialize the module as appropriate for Macintosh systems"""
      g = {}
      # set basic install directories
      g['LIBDEST'] = get_python_lib(plat_specific=0, standard_lib=1)
      g['BINLIBDEST'] = get_python_lib(plat_specific=1, standard_lib=1)
  
      # XXX hmmm.. a normal install puts include files here
      g['INCLUDEPY'] = get_python_inc(plat_specific=0)
  
      import MacOS
      if not hasattr(MacOS, 'runtimemodel'):
          g['SO'] = '.ppc.slb'
      else:
          g['SO'] = '.%s.slb' % MacOS.runtimemodel
  
      # XXX are these used anywhere?
      g['install_lib'] = os.path.join(EXEC_PREFIX, "Lib")
      g['install_platlib'] = os.path.join(EXEC_PREFIX, "Mac", "Lib")
  
      # These are used by the extension module build
      g['srcdir'] = ':'
      global _config_vars
      _config_vars = g
  
  
  def _init_os2():
      """Initialize the module as appropriate for OS/2"""
      g = {}
      # set basic install directories
      g['LIBDEST'] = get_python_lib(plat_specific=0, standard_lib=1)
      g['BINLIBDEST'] = get_python_lib(plat_specific=1, standard_lib=1)
  
      # XXX hmmm.. a normal install puts include files here
      g['INCLUDEPY'] = get_python_inc(plat_specific=0)
  
      g['SO'] = '.pyd'
      g['EXE'] = ".exe"
  
      global _config_vars
      _config_vars = g
  
  
  def get_config_vars(*args):
      """With no arguments, return a dictionary of all configuration
      variables relevant for the current platform.  Generally this includes
      everything needed to build extensions and install both pure modules and
      extensions.  On Unix, this means every variable defined in Python's
      installed Makefile; on Windows and Mac OS it's a much smaller set.
  
      With arguments, return a list of values that result from looking up
      each argument in the configuration variable dictionary.
      """
      global _config_vars
      if _config_vars is None:
          func = globals().get("_init_" + os.name)
          if func:
              func()
          else:
              _config_vars = {}
  
          # Normalized versions of prefix and exec_prefix are handy to have;
          # in fact, these are the standard versions used most places in the
          # Distutils.
          _config_vars['prefix'] = PREFIX
          _config_vars['exec_prefix'] = EXEC_PREFIX
  
          # Convert srcdir into an absolute path if it appears necessary.
          # Normally it is relative to the build directory.  However, during
          # testing, for example, we might be running a non-installed python
          # from a different directory.
          if python_build and os.name == "posix":
              base = os.path.dirname(os.path.abspath(sys.executable))
              if (not os.path.isabs(_config_vars['srcdir']) and
                  base != os.getcwd()):
                  # srcdir is relative and we are not in the same directory
                  # as the executable. Assume executable is in the build
                  # directory and make srcdir absolute.
                  srcdir = os.path.join(base, _config_vars['srcdir'])
                  _config_vars['srcdir'] = os.path.normpath(srcdir)
  
          if sys.platform == 'darwin':
              kernel_version = os.uname()[2] # Kernel version (8.4.3)
              major_version = int(kernel_version.split('.')[0])
  
              if major_version < 8:
                  # On Mac OS X before 10.4, check if -arch and -isysroot
                  # are in CFLAGS or LDFLAGS and remove them if they are.
                  # This is needed when building extensions on a 10.3 system
                  # using a universal build of python.
                  for key in ('LDFLAGS', 'BASECFLAGS',
                          # a number of derived variables. These need to be
                          # patched up as well.
                          'CFLAGS', 'PY_CFLAGS', 'BLDSHARED'):
                      flags = _config_vars[key]
                      flags = re.sub('-arch\s+\w+\s', ' ', flags, re.ASCII)
                      flags = re.sub('-isysroot [^ \t]*', ' ', flags)
                      _config_vars[key] = flags
  
              else:
  
                  # Allow the user to override the architecture flags using
                  # an environment variable.
                  # NOTE: This name was introduced by Apple in OSX 10.5 and
                  # is used by several scripting languages distributed with
                  # that OS release.
  
                  if 'ARCHFLAGS' in os.environ:
                      arch = os.environ['ARCHFLAGS']
                      for key in ('LDFLAGS', 'BASECFLAGS',
                          # a number of derived variables. These need to be
                          # patched up as well.
                          'CFLAGS', 'PY_CFLAGS', 'BLDSHARED'):
  
                          flags = _config_vars[key]
                          flags = re.sub('-arch\s+\w+\s', ' ', flags)
                          flags = flags + ' ' + arch
                          _config_vars[key] = flags
  
      if args:
          vals = []
          for name in args:
              vals.append(_config_vars.get(name))
          return vals
      else:
          return _config_vars
  
  def get_config_var(name):
      """Return the value of a single variable using the dictionary
      returned by 'get_config_vars()'.  Equivalent to
      get_config_vars().get(name)
      """
      return get_config_vars().get(name)
  