text: # Copyright 2012-2020 The Meson development team
  
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  
  #     http://www.apache.org/licenses/LICENSE-2.0
  
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  """A library of random helper functionality."""
  from pathlib import Path
  import enum
  import sys
  import stat
  import time
  import platform, subprocess, operator, os, shlex, shutil, re
  import collections
  from functools import lru_cache, wraps, total_ordering
  from itertools import tee, filterfalse
  from tempfile import TemporaryDirectory
  import typing as T
  import uuid
  import textwrap
  
  from mesonbuild import mlog
  
  if T.TYPE_CHECKING:
      from .build import ConfigurationData
      from .coredata import KeyedOptionDictType, UserOption
      from .compilers.compilers import CompilerType
      from .interpreterbase import ObjectHolder
  
      FileOrString = T.Union['File', str]
  
  _T = T.TypeVar('_T')
  _U = T.TypeVar('_U')
  
  have_fcntl = False
  have_msvcrt = False
  # TODO: this is such a hack, this really should be either in coredata or in the
  # interpreter
  # {subproject: project_meson_version}
  project_meson_versions = collections.defaultdict(str)  # type: T.DefaultDict[str, str]
  
  try:
      import fcntl
      have_fcntl = True
  except Exception:
      pass
  
  try:
      import msvcrt
      have_msvcrt = True
  except Exception:
      pass
  
  from glob import glob
  
  if os.path.basename(sys.executable) == 'meson.exe':
      # In Windows and using the MSI installed executable.
      python_command = [sys.executable, 'runpython']
  else:
      python_command = [sys.executable]
  meson_command = None
  
  class MesonException(Exception):
      '''Exceptions thrown by Meson'''
  
      def __init__(self, *args: object, file: T.Optional[str] = None,
                   lineno: T.Optional[int] = None, colno: T.Optional[int] = None):
          super().__init__(*args)
          self.file = file
          self.lineno = lineno
          self.colno = colno
  
  
  class EnvironmentException(MesonException):
      '''Exceptions thrown while processing and creating the build environment'''
  
  class GitException(MesonException):
      def __init__(self, msg: str, output: T.Optional[str] = None):
          super().__init__(msg)
          self.output = output.strip() if output else ''
  
  GIT = shutil.which('git')
  def git(cmd: T.List[str], workingdir: str, check: bool = False, **kwargs: T.Any) -> T.Tuple[subprocess.Popen, str, str]:
      cmd = [GIT] + cmd
      p, o, e = Popen_safe(cmd, cwd=workingdir, **kwargs)
      if check and p.returncode != 0:
          raise GitException('Git command failed: ' + str(cmd), e)
      return p, o, e
  
  def quiet_git(cmd: T.List[str], workingdir: str, check: bool = False) -> T.Tuple[bool, str]:
      if not GIT:
          m = 'Git program not found.'
          if check:
              raise GitException(m)
          return False, m
      p, o, e = git(cmd, workingdir, check)
      if p.returncode != 0:
          return False, e
      return True, o
  
  def verbose_git(cmd: T.List[str], workingdir: str, check: bool = False) -> bool:
      if not GIT:
          m = 'Git program not found.'
          if check:
              raise GitException(m)
          return False
      p, _, _ = git(cmd, workingdir, check, stdout=None, stderr=None)
      return p.returncode == 0
  
  def set_meson_command(mainfile: str) -> None:
      global python_command
      global meson_command
      # On UNIX-like systems `meson` is a Python script
      # On Windows `meson` and `meson.exe` are wrapper exes
      if not mainfile.endswith('.py'):
          meson_command = [mainfile]
      elif os.path.isabs(mainfile) and mainfile.endswith('mesonmain.py'):
          # Can't actually run meson with an absolute path to mesonmain.py, it must be run as -m mesonbuild.mesonmain
          meson_command = python_command + ['-m', 'mesonbuild.mesonmain']
      else:
          # Either run uninstalled, or full path to meson-script.py
          meson_command = python_command + [mainfile]
      # We print this value for unit tests.
      if 'MESON_COMMAND_TESTS' in os.environ:
          mlog.log('meson_command is {!r}'.format(meson_command))
  
  
  def is_ascii_string(astring: T.Union[str, bytes]) -> bool:
      try:
          if isinstance(astring, str):
              astring.encode('ascii')
          elif isinstance(astring, bytes):
              astring.decode('ascii')
      except UnicodeDecodeError:
          return False
      return True
  
  
  def check_direntry_issues(direntry_array: T.Union[T.List[T.Union[str, bytes]], str, bytes]) -> None:
      import locale
      # Warn if the locale is not UTF-8. This can cause various unfixable issues
      # such as os.stat not being able to decode filenames with unicode in them.
      # There is no way to reset both the preferred encoding and the filesystem
      # encoding, so we can just warn about it.
      e = locale.getpreferredencoding()
      if e.upper() != 'UTF-8' and not is_windows():
          if not isinstance(direntry_array, list):
              direntry_array = [direntry_array]
          for de in direntry_array:
              if is_ascii_string(de):
                  continue
              mlog.warning(textwrap.dedent('''
                  You are using {!r} which is not a Unicode-compatible
                  locale but you are trying to access a file system entry called {!r} which is
                  not pure ASCII. This may cause problems.
                  '''.format(e, de)), file=sys.stderr)
  
  
  # Put this in objects that should not get dumped to pickle files
  # by accident.
  import threading
  an_unpicklable_object = threading.Lock()
  
  class FileMode:
      # The first triad is for owner permissions, the second for group permissions,
      # and the third for others (everyone else).
      # For the 1st character:
      #  'r' means can read
      #  '-' means not allowed
      # For the 2nd character:
      #  'w' means can write
      #  '-' means not allowed
      # For the 3rd character:
      #  'x' means can execute
      #  's' means can execute and setuid/setgid is set (owner/group triads only)
      #  'S' means cannot execute and setuid/setgid is set (owner/group triads only)
      #  't' means can execute and sticky bit is set ("others" triads only)
      #  'T' means cannot execute and sticky bit is set ("others" triads only)
      #  '-' means none of these are allowed
      #
      # The meanings of 'rwx' perms is not obvious for directories; see:
      # https://www.hackinglinuxexposed.com/articles/20030424.html
      #
      # For information on this notation such as setuid/setgid/sticky bits, see:
      # https://en.wikipedia.org/wiki/File_system_permissions#Symbolic_notation
      symbolic_perms_regex = re.compile('[r-][w-][xsS-]' # Owner perms
                                        '[r-][w-][xsS-]' # Group perms
                                        '[r-][w-][xtT-]') # Others perms
  
      def __init__(self, perms: T.Optional[str] = None, owner: T.Optional[str] = None,
                   group: T.Optional[str] = None):
          self.perms_s = perms
          self.perms = self.perms_s_to_bits(perms)
          self.owner = owner
          self.group = group
  
      def __repr__(self) -> str:
          ret = '<FileMode: {!r} owner={} group={}'
          return ret.format(self.perms_s, self.owner, self.group)
  
      @classmethod
      def perms_s_to_bits(cls, perms_s: T.Optional[str]) -> int:
          '''
          Does the opposite of stat.filemode(), converts strings of the form
          'rwxr-xr-x' to st_mode enums which can be passed to os.chmod()
          '''
          if perms_s is None:
              # No perms specified, we will not touch the permissions
              return -1
          eg = 'rwxr-xr-x'
          if not isinstance(perms_s, str):
              msg = 'Install perms must be a string. For example, {!r}'
              raise MesonException(msg.format(eg))
          if len(perms_s) != 9 or not cls.symbolic_perms_regex.match(perms_s):
              msg = 'File perms {!r} must be exactly 9 chars. For example, {!r}'
              raise MesonException(msg.format(perms_s, eg))
          perms = 0
          # Owner perms
          if perms_s[0] == 'r':
              perms |= stat.S_IRUSR
          if perms_s[1] == 'w':
              perms |= stat.S_IWUSR
          if perms_s[2] == 'x':
              perms |= stat.S_IXUSR
          elif perms_s[2] == 'S':
              perms |= stat.S_ISUID
          elif perms_s[2] == 's':
              perms |= stat.S_IXUSR
              perms |= stat.S_ISUID
          # Group perms
          if perms_s[3] == 'r':
              perms |= stat.S_IRGRP
          if perms_s[4] == 'w':
              perms |= stat.S_IWGRP
          if perms_s[5] == 'x':
              perms |= stat.S_IXGRP
          elif perms_s[5] == 'S':
              perms |= stat.S_ISGID
          elif perms_s[5] == 's':
              perms |= stat.S_IXGRP
              perms |= stat.S_ISGID
          # Others perms
          if perms_s[6] == 'r':
              perms |= stat.S_IROTH
          if perms_s[7] == 'w':
              perms |= stat.S_IWOTH
          if perms_s[8] == 'x':
              perms |= stat.S_IXOTH
          elif perms_s[8] == 'T':
              perms |= stat.S_ISVTX
          elif perms_s[8] == 't':
              perms |= stat.S_IXOTH
              perms |= stat.S_ISVTX
          return perms
  
  class File:
      def __init__(self, is_built: bool, subdir: str, fname: str):
          self.is_built = is_built
          self.subdir = subdir
          self.fname = fname
          self.hash = hash((is_built, subdir, fname))
  
      def __str__(self) -> str:
          return self.relative_name()
  
      def __repr__(self) -> str:
          ret = '<File: {0}'
          if not self.is_built:
              ret += ' (not built)'
          ret += '>'
          return ret.format(self.relative_name())
  
      @staticmethod
      @lru_cache(maxsize=None)
      def from_source_file(source_root: str, subdir: str, fname: str) -> 'File':
          if not os.path.isfile(os.path.join(source_root, subdir, fname)):
              raise MesonException('File %s does not exist.' % fname)
          return File(False, subdir, fname)
  
      @staticmethod
      def from_built_file(subdir: str, fname: str) -> 'File':
          return File(True, subdir, fname)
  
      @staticmethod
      def from_absolute_file(fname: str) -> 'File':
          return File(False, '', fname)
  
      @lru_cache(maxsize=None)
      def rel_to_builddir(self, build_to_src: str) -> str:
          if self.is_built:
              return self.relative_name()
          else:
              return os.path.join(build_to_src, self.subdir, self.fname)
  
      @lru_cache(maxsize=None)
      def absolute_path(self, srcdir: str, builddir: str) -> str:
          absdir = srcdir
          if self.is_built:
              absdir = builddir
          return os.path.join(absdir, self.relative_name())
  
      def endswith(self, ending: str) -> bool:
          return self.fname.endswith(ending)
  
      def split(self, s: str) -> T.List[str]:
          return self.fname.split(s)
  
      def __eq__(self, other: object) -> bool:
          if not isinstance(other, File):
              return NotImplemented
          if self.hash != other.hash:
              return False
          return (self.fname, self.subdir, self.is_built) == (other.fname, other.subdir, other.is_built)
  
      def __hash__(self) -> int:
          return self.hash
  
      @lru_cache(maxsize=None)
      def relative_name(self) -> str:
          return os.path.join(self.subdir, self.fname)
  
  
  def get_compiler_for_source(compilers: T.Iterable['CompilerType'], src: str) -> 'CompilerType':
      """Given a set of compilers and a source, find the compiler for that source type."""
      for comp in compilers:
          if comp.can_compile(src):
              return comp
      raise MesonException('No specified compiler can handle file {!s}'.format(src))
  
  
  def classify_unity_sources(compilers: T.Iterable['CompilerType'], sources: T.Iterable[str]) -> T.Dict['CompilerType', T.List[str]]:
      compsrclist = {}  # type: T.Dict[CompilerType, T.List[str]]
      for src in sources:
          comp = get_compiler_for_source(compilers, src)
          if comp not in compsrclist:
              compsrclist[comp] = [src]
          else:
              compsrclist[comp].append(src)
      return compsrclist
  
  
  class MachineChoice(enum.IntEnum):
  
      """Enum class representing one of the two abstract machine names used in
      most places: the build, and host, machines.
      """
  
      BUILD = 0
      HOST = 1
  
      def get_lower_case_name(self) -> str:
          return PerMachine('build', 'host')[self]
  
      def get_prefix(self) -> str:
          return PerMachine('build.', '')[self]
  
  
  class PerMachine(T.Generic[_T]):
      def __init__(self, build: _T, host: _T) -> None:
          self.build = build
          self.host = host
  
      def __getitem__(self, machine: MachineChoice) -> _T:
          return {
              MachineChoice.BUILD:  self.build,
              MachineChoice.HOST:   self.host,
          }[machine]
  
      def __setitem__(self, machine: MachineChoice, val: _T) -> None:
          setattr(self, machine.get_lower_case_name(), val)
  
      def miss_defaulting(self) -> "PerMachineDefaultable[T.Optional[_T]]":
          """Unset definition duplicated from their previous to None
  
          This is the inverse of ''default_missing''. By removing defaulted
          machines, we can elaborate the original and then redefault them and thus
          avoid repeating the elaboration explicitly.
          """
          unfreeze = PerMachineDefaultable() # type: PerMachineDefaultable[T.Optional[_T]]
          unfreeze.build = self.build
          unfreeze.host = self.host
          if unfreeze.host == unfreeze.build:
              unfreeze.host = None
          return unfreeze
  
      def __repr__(self) -> str:
          return 'PerMachine({!r}, {!r})'.format(self.build, self.host)
  
  
  class PerThreeMachine(PerMachine[_T]):
      """Like `PerMachine` but includes `target` too.
  
      It turns out just one thing do we need track the target machine. There's no
      need to computer the `target` field so we don't bother overriding the
      `__getitem__`/`__setitem__` methods.
      """
      def __init__(self, build: _T, host: _T, target: _T) -> None:
          super().__init__(build, host)
          self.target = target
  
      def miss_defaulting(self) -> "PerThreeMachineDefaultable[T.Optional[_T]]":
          """Unset definition duplicated from their previous to None
  
          This is the inverse of ''default_missing''. By removing defaulted
          machines, we can elaborate the original and then redefault them and thus
          avoid repeating the elaboration explicitly.
          """
          unfreeze = PerThreeMachineDefaultable() # type: PerThreeMachineDefaultable[T.Optional[_T]]
          unfreeze.build = self.build
          unfreeze.host = self.host
          unfreeze.target = self.target
          if unfreeze.target == unfreeze.host:
              unfreeze.target = None
          if unfreeze.host == unfreeze.build:
              unfreeze.host = None
          return unfreeze
  
      def matches_build_machine(self, machine: MachineChoice) -> bool:
          return self.build == self[machine]
  
      def __repr__(self) -> str:
          return 'PerThreeMachine({!r}, {!r}, {!r})'.format(self.build, self.host, self.target)
  
  
  class PerMachineDefaultable(PerMachine[T.Optional[_T]]):
      """Extends `PerMachine` with the ability to default from `None`s.
      """
      def __init__(self) -> None:
          super().__init__(None, None)
  
      def default_missing(self) -> "PerMachine[T.Optional[_T]]":
          """Default host to build
  
          This allows just specifying nothing in the native case, and just host in the
          cross non-compiler case.
          """
          freeze = PerMachine(self.build, self.host)
          if freeze.host is None:
              freeze.host = freeze.build
          return freeze
  
      def __repr__(self) -> str:
          return 'PerMachineDefaultable({!r}, {!r})'.format(self.build, self.host)
  
  
  class PerThreeMachineDefaultable(PerMachineDefaultable, PerThreeMachine[T.Optional[_T]]):
      """Extends `PerThreeMachine` with the ability to default from `None`s.
      """
      def __init__(self) -> None:
          PerThreeMachine.__init__(self, None, None, None)
  
      def default_missing(self) -> "PerThreeMachine[T.Optional[_T]]":
          """Default host to build and target to host.
  
          This allows just specifying nothing in the native case, just host in the
          cross non-compiler case, and just target in the native-built
          cross-compiler case.
          """
          freeze = PerThreeMachine(self.build, self.host, self.target)
          if freeze.host is None:
              freeze.host = freeze.build
          if freeze.target is None:
              freeze.target = freeze.host
          return freeze
  
      def __repr__(self) -> str:
          return 'PerThreeMachineDefaultable({!r}, {!r}, {!r})'.format(self.build, self.host, self.target)
  
  
  def is_sunos() -> bool:
      return platform.system().lower() == 'sunos'
  
  
  def is_osx() -> bool:
      return platform.system().lower() == 'darwin'
  
  
  def is_linux() -> bool:
      return platform.system().lower() == 'linux'
  
  
  def is_android() -> bool:
      return platform.system().lower() == 'android'
  
  
  def is_haiku() -> bool:
      return platform.system().lower() == 'haiku'
  
  
  def is_openbsd() -> bool:
      return platform.system().lower() == 'openbsd'
  
  
  def is_windows() -> bool:
      platname = platform.system().lower()
      return platname == 'windows'
  
  
  def is_cygwin() -> bool:
      return sys.platform == 'cygwin'
  
  
  def is_debianlike() -> bool:
      return os.path.isfile('/etc/debian_version')
  
  
  def is_dragonflybsd() -> bool:
      return platform.system().lower() == 'dragonfly'
  
  
  def is_netbsd() -> bool:
      return platform.system().lower() == 'netbsd'
  
  
  def is_freebsd() -> bool:
      return platform.system().lower() == 'freebsd'
  
  def is_irix() -> bool:
      return platform.system().startswith('irix')
  
  def is_hurd() -> bool:
      return platform.system().lower() == 'gnu'
  
  def is_qnx() -> bool:
      return platform.system().lower() == 'qnx'
  
  def is_aix() -> bool:
      return platform.system().lower() == 'aix'
  
  def exe_exists(arglist: T.List[str]) -> bool:
      try:
          if subprocess.run(arglist, timeout=10).returncode == 0:
              return True
      except (FileNotFoundError, subprocess.TimeoutExpired):
          pass
      return False
  
  
  @lru_cache(maxsize=None)
  def darwin_get_object_archs(objpath: str) -> T.List[str]:
      '''
      For a specific object (executable, static library, dylib, etc), run `lipo`
      to fetch the list of archs supported by it. Supports both thin objects and
      'fat' objects.
      '''
      _, stdo, stderr = Popen_safe(['lipo', '-info', objpath])
      if not stdo:
          mlog.debug('lipo {}: {}'.format(objpath, stderr))
          return None
      stdo = stdo.rsplit(': ', 1)[1]
      # Convert from lipo-style archs to meson-style CPUs
      stdo = stdo.replace('i386', 'x86')
      stdo = stdo.replace('arm64', 'aarch64')
      # Add generic name for armv7 and armv7s
      if 'armv7' in stdo:
          stdo += ' arm'
      return stdo.split()
  
  
  def detect_vcs(source_dir: T.Union[str, Path]) -> T.Optional[T.Dict[str, str]]:
      vcs_systems = [
          dict(name = 'git',        cmd = 'git', repo_dir = '.git', get_rev = 'git describe --dirty=+', rev_regex = '(.*)', dep = '.git/logs/HEAD'),
          dict(name = 'mercurial',  cmd = 'hg',  repo_dir = '.hg',  get_rev = 'hg id -i',               rev_regex = '(.*)', dep = '.hg/dirstate'),
          dict(name = 'subversion', cmd = 'svn', repo_dir = '.svn', get_rev = 'svn info',               rev_regex = 'Revision: (.*)', dep = '.svn/wc.db'),
          dict(name = 'bazaar',     cmd = 'bzr', repo_dir = '.bzr', get_rev = 'bzr revno',              rev_regex = '(.*)', dep = '.bzr'),
      ]
      if isinstance(source_dir, str):
          source_dir = Path(source_dir)
  
      parent_paths_and_self = collections.deque(source_dir.parents)
      # Prepend the source directory to the front so we can check it;
      # source_dir.parents doesn't include source_dir
      parent_paths_and_self.appendleft(source_dir)
      for curdir in parent_paths_and_self:
          for vcs in vcs_systems:
              if Path.is_dir(curdir.joinpath(vcs['repo_dir'])) and shutil.which(vcs['cmd']):
                  vcs['wc_dir'] = str(curdir)
                  return vcs
      return None
  
  def current_vs_supports_modules() -> bool:
      vsver = os.environ.get('VSCMD_VER', '')
      return vsver.startswith('16.9.0') and '-pre.' in vsver
  
  # a helper class which implements the same version ordering as RPM
  class Version:
      def __init__(self, s: str) -> None:
          self._s = s
  
          # split into numeric, alphabetic and non-alphanumeric sequences
          sequences1 = re.finditer(r'(\d+|[a-zA-Z]+|[^a-zA-Z\d]+)', s)
  
          # non-alphanumeric separators are discarded
          sequences2 = [m for m in sequences1 if not re.match(r'[^a-zA-Z\d]+', m.group(1))]
  
          # numeric sequences are converted from strings to ints
          sequences3 = [int(m.group(1)) if m.group(1).isdigit() else m.group(1) for m in sequences2]
  
          self._v = sequences3
  
      def __str__(self) -> str:
          return '%s (V=%s)' % (self._s, str(self._v))
  
      def __repr__(self) -> str:
          return '<Version: {}>'.format(self._s)
  
      def __lt__(self, other: object) -> bool:
          if isinstance(other, Version):
              return self.__cmp(other, operator.lt)
          return NotImplemented
  
      def __gt__(self, other: object) -> bool:
          if isinstance(other, Version):
              return self.__cmp(other, operator.gt)
          return NotImplemented
  
      def __le__(self, other: object) -> bool:
          if isinstance(other, Version):
              return self.__cmp(other, operator.le)
          return NotImplemented
  
      def __ge__(self, other: object) -> bool:
          if isinstance(other, Version):
              return self.__cmp(other, operator.ge)
          return NotImplemented
  
      def __eq__(self, other: object) -> bool:
          if isinstance(other, Version):
              return self._v == other._v
          return NotImplemented
  
      def __ne__(self, other: object) -> bool:
          if isinstance(other, Version):
              return self._v != other._v
          return NotImplemented
  
      def __cmp(self, other: 'Version', comparator: T.Callable[[T.Any, T.Any], bool]) -> bool:
          # compare each sequence in order
          for ours, theirs in zip(self._v, other._v):
              # sort a non-digit sequence before a digit sequence
              ours_is_int = isinstance(ours, int)
              theirs_is_int = isinstance(theirs, int)
              if ours_is_int != theirs_is_int:
                  return comparator(ours_is_int, theirs_is_int)
  
              if ours != theirs:
                  return comparator(ours, theirs)
  
          # if equal length, all components have matched, so equal
          # otherwise, the version with a suffix remaining is greater
          return comparator(len(self._v), len(other._v))
  
  
  def _version_extract_cmpop(vstr2: str) -> T.Tuple[T.Callable[[T.Any, T.Any], bool], str]:
      if vstr2.startswith('>='):
          cmpop = operator.ge
          vstr2 = vstr2[2:]
      elif vstr2.startswith('<='):
          cmpop = operator.le
          vstr2 = vstr2[2:]
      elif vstr2.startswith('!='):
          cmpop = operator.ne
          vstr2 = vstr2[2:]
      elif vstr2.startswith('=='):
          cmpop = operator.eq
          vstr2 = vstr2[2:]
      elif vstr2.startswith('='):
          cmpop = operator.eq
          vstr2 = vstr2[1:]
      elif vstr2.startswith('>'):
          cmpop = operator.gt
          vstr2 = vstr2[1:]
      elif vstr2.startswith('<'):
          cmpop = operator.lt
          vstr2 = vstr2[1:]
      else:
          cmpop = operator.eq
  
      return (cmpop, vstr2)
  
  
  def version_compare(vstr1: str, vstr2: str) -> bool:
      (cmpop, vstr2) = _version_extract_cmpop(vstr2)
      return cmpop(Version(vstr1), Version(vstr2))
  
  
  def version_compare_many(vstr1: str, conditions: T.Union[str, T.Iterable[str]]) -> T.Tuple[bool, T.List[str], T.List[str]]:
      if isinstance(conditions, str):
          conditions = [conditions]
      found = []
      not_found = []
      for req in conditions:
          if not version_compare(vstr1, req):
              not_found.append(req)
          else:
              found.append(req)
      return not_found == [], not_found, found
  
  
  # determine if the minimum version satisfying the condition |condition| exceeds
  # the minimum version for a feature |minimum|
  def version_compare_condition_with_min(condition: str, minimum: str) -> bool:
      if condition.startswith('>='):
          cmpop = operator.le
          condition = condition[2:]
      elif condition.startswith('<='):
          return False
      elif condition.startswith('!='):
          return False
      elif condition.startswith('=='):
          cmpop = operator.le
          condition = condition[2:]
      elif condition.startswith('='):
          cmpop = operator.le
          condition = condition[1:]
      elif condition.startswith('>'):
          cmpop = operator.lt
          condition = condition[1:]
      elif condition.startswith('<'):
          return False
      else:
          cmpop = operator.le
  
      # Declaring a project(meson_version: '>=0.46') and then using features in
      # 0.46.0 is valid, because (knowing the meson versioning scheme) '0.46.0' is
      # the lowest version which satisfies the constraint '>=0.46'.
      #
      # But this will fail here, because the minimum version required by the
      # version constraint ('0.46') is strictly less (in our version comparison)
      # than the minimum version needed for the feature ('0.46.0').
      #
      # Map versions in the constraint of the form '0.46' to '0.46.0', to embed
      # this knowledge of the meson versioning scheme.
      condition = condition.strip()
      if re.match(r'^\d+.\d+$', condition):
          condition += '.0'
  
      return T.cast(bool, cmpop(Version(minimum), Version(condition)))
  
  
  def default_libdir() -> str:
      if is_debianlike():
          try:
              pc = subprocess.Popen(['dpkg-architecture', '-qDEB_HOST_MULTIARCH'],
                                    stdout=subprocess.PIPE,
                                    stderr=subprocess.DEVNULL)
              (stdo, _) = pc.communicate()
              if pc.returncode == 0:
                  archpath = stdo.decode().strip()
                  return 'lib/' + archpath
          except Exception:
              pass
      if is_freebsd() or is_irix():
          return 'lib'
      if os.path.isdir('/usr/lib64') and not os.path.islink('/usr/lib64'):
          return 'lib64'
      return 'lib'
  
  
  def default_libexecdir() -> str:
      # There is no way to auto-detect this, so it must be set at build time
      return 'libexec'
  
  
  def default_prefix() -> str:
      return 'c:/' if is_windows() else '/usr/local'
  
  
  def get_library_dirs() -> T.List[str]:
      if is_windows():
          return ['C:/mingw/lib'] # TODO: get programmatically
      if is_osx():
          return ['/usr/lib'] # TODO: get programmatically
      # The following is probably Debian/Ubuntu specific.
      # /usr/local/lib is first because it contains stuff
      # installed by the sysadmin and is probably more up-to-date
      # than /usr/lib. If you feel that this search order is
      # problematic, please raise the issue on the mailing list.
      unixdirs = ['/usr/local/lib', '/usr/lib', '/lib']
  
      if is_freebsd():
          return unixdirs
      # FIXME: this needs to be further genericized for aarch64 etc.
      machine = platform.machine()
      if machine in ('i386', 'i486', 'i586', 'i686'):
          plat = 'i386'
      elif machine.startswith('arm'):
          plat = 'arm'
      else:
          plat = ''
  
      # Solaris puts 32-bit libraries in the main /lib & /usr/lib directories
      # and 64-bit libraries in platform specific subdirectories.
      if is_sunos():
          if machine == 'i86pc':
              plat = 'amd64'
          elif machine.startswith('sun4'):
              plat = 'sparcv9'
  
      usr_platdir = Path('/usr/lib/') / plat
      if usr_platdir.is_dir():
          unixdirs += [str(x) for x in (usr_platdir).iterdir() if x.is_dir()]
      if os.path.exists('/usr/lib64'):
          unixdirs.append('/usr/lib64')
  
      lib_platdir = Path('/lib/') / plat
      if lib_platdir.is_dir():
          unixdirs += [str(x) for x in (lib_platdir).iterdir() if x.is_dir()]
      if os.path.exists('/lib64'):
          unixdirs.append('/lib64')
  
      return unixdirs
  
  
  def has_path_sep(name: str, sep: str = '/\\') -> bool:
      'Checks if any of the specified @sep path separators are in @name'
      for each in sep:
          if each in name:
              return True
      return False
  
  
  if is_windows():
      # shlex.split is not suitable for splitting command line on Window (https://bugs.python.org/issue1724822);
      # shlex.quote is similarly problematic. Below are "proper" implementations of these functions according to
      # https://docs.microsoft.com/en-us/cpp/c-language/parsing-c-command-line-arguments and
      # https://blogs.msdn.microsoft.com/twistylittlepassagesallalike/2011/04/23/everyone-quotes-command-line-arguments-the-wrong-way/
  
      _whitespace = ' \t\n\r'
      _find_unsafe_char = re.compile(r'[{}"]'.format(_whitespace)).search
  
      def quote_arg(arg: str) -> str:
          if arg and not _find_unsafe_char(arg):
              return arg
  
          result = '"'
          num_backslashes = 0
          for c in arg:
              if c == '\\':
                  num_backslashes += 1
              else:
                  if c == '"':
                      # Escape all backslashes and the following double quotation mark
                      num_backslashes = num_backslashes * 2 + 1
  
                  result += num_backslashes * '\\' + c
                  num_backslashes = 0
  
          # Escape all backslashes, but let the terminating double quotation
          # mark we add below be interpreted as a metacharacter
          result += (num_backslashes * 2) * '\\' + '"'
          return result
  
      def split_args(cmd: str) -> T.List[str]:
          result = []
          arg = ''
          num_backslashes = 0
          num_quotes = 0
          in_quotes = False
          for c in cmd:
              if c == '\\':
                  num_backslashes += 1
              else:
                  if c == '"' and not (num_backslashes % 2):
                      # unescaped quote, eat it
                      arg += (num_backslashes // 2) * '\\'
                      num_quotes += 1
                      in_quotes = not in_quotes
                  elif c in _whitespace and not in_quotes:
                      if arg or num_quotes:
                          # reached the end of the argument
                          result.append(arg)
                          arg = ''
                          num_quotes = 0
                  else:
                      if c == '"':
                          # escaped quote
                          num_backslashes = (num_backslashes - 1) // 2
  
                      arg += num_backslashes * '\\' + c
  
                  num_backslashes = 0
  
          if arg or num_quotes:
              result.append(arg)
  
          return result
  else:
      def quote_arg(arg: str) -> str:
          return shlex.quote(arg)
  
      def split_args(cmd: str) -> T.List[str]:
          return shlex.split(cmd)
  
  
  def join_args(args: T.Iterable[str]) -> str:
      return ' '.join([quote_arg(x) for x in args])
  
  
  def do_replacement(regex: T.Pattern[str], line: str, variable_format: str,
                     confdata: 'ConfigurationData') -> T.Tuple[str, T.Set[str]]:
      missing_variables = set()  # type: T.Set[str]
      if variable_format == 'cmake':
          start_tag = '${'
          backslash_tag = '\\${'
      else:
          assert variable_format in ['meson', 'cmake@']
          start_tag = '@'
          backslash_tag = '\\@'
  
      def variable_replace(match: T.Match[str]) -> str:
          # Pairs of escape characters before '@' or '\@'
          if match.group(0).endswith('\\'):
              num_escapes = match.end(0) - match.start(0)
              return '\\' * (num_escapes // 2)
          # Single escape character and '@'
          elif match.group(0) == backslash_tag:
              return start_tag
          # Template variable to be replaced
          else:
              varname = match.group(1)
              var_str = ''
              if varname in confdata:
                  (var, desc) = confdata.get(varname)
                  if isinstance(var, str):
                      var_str = var
                  elif isinstance(var, int):
                      var_str = str(var)
                  else:
                      msg = 'Tried to replace variable {!r} value with ' \
                            'something other than a string or int: {!r}'
                      raise MesonException(msg.format(varname, var))
              else:
                  missing_variables.add(varname)
              return var_str
      return re.sub(regex, variable_replace, line), missing_variables
  
  def do_define(regex: T.Pattern[str], line: str, confdata: 'ConfigurationData', variable_format: str) -> str:
      def get_cmake_define(line: str, confdata: 'ConfigurationData') -> str:
          arr = line.split()
          define_value=[]
          for token in arr[2:]:
              try:
                  (v, desc) = confdata.get(token)
                  define_value += [str(v)]
              except KeyError:
                  define_value += [token]
          return ' '.join(define_value)
  
      arr = line.split()
      if variable_format == 'meson' and len(arr) != 2:
          raise MesonException('#mesondefine does not contain exactly two tokens: %s' % line.strip())
  
      varname = arr[1]
      try:
          (v, desc) = confdata.get(varname)
      except KeyError:
          return '/* #undef %s */\n' % varname
      if isinstance(v, bool):
          if v:
              return '#define %s\n' % varname
          else:
              return '#undef %s\n' % varname
      elif isinstance(v, int):
          return '#define %s %d\n' % (varname, v)
      elif isinstance(v, str):
          if variable_format == 'meson':
              result = v
          else:
              result = get_cmake_define(line, confdata)
          result = '#define %s %s\n' % (varname, result)
          (result, missing_variable) = do_replacement(regex, result, variable_format, confdata)
          return result
      else:
          raise MesonException('#mesondefine argument "%s" is of unknown type.' % varname)
  
  def get_variable_regex(variable_format: str = 'meson') -> T.Pattern[str]:
      # Only allow (a-z, A-Z, 0-9, _, -) as valid characters for a define
      # Also allow escaping '@' with '\@'
      if variable_format in ['meson', 'cmake@']:
          regex = re.compile(r'(?:\\\\)+(?=\\?@)|\\@|@([-a-zA-Z0-9_]+)@')
      elif variable_format == 'cmake':
          regex = re.compile(r'(?:\\\\)+(?=\\?\$)|\\\${|\${([-a-zA-Z0-9_]+)}')
      else:
          raise MesonException('Format "{}" not handled'.format(variable_format))
      return regex
  
  def do_conf_str (data: list, confdata: 'ConfigurationData', variable_format: str,
                   encoding: str = 'utf-8') -> T.Tuple[T.List[str],T.Set[str], bool]:
      def line_is_valid(line : str, variable_format: str) -> bool:
          if variable_format == 'meson':
              if '#cmakedefine' in line:
                  return False
          else: #cmake format
              if '#mesondefine' in line:
                  return False
          return True
  
      regex = get_variable_regex(variable_format)
  
      search_token = '#mesondefine'
      if variable_format != 'meson':
          search_token = '#cmakedefine'
  
      result = []
      missing_variables = set()
      # Detect when the configuration data is empty and no tokens were found
      # during substitution so we can warn the user to use the `copy:` kwarg.
      confdata_useless = not confdata.keys()
      for line in data:
          if line.startswith(search_token):
              confdata_useless = False
              line = do_define(regex, line, confdata, variable_format)
          else:
              if not line_is_valid(line,variable_format):
                  raise MesonException('Format "{}" mismatched'.format(variable_format))
              line, missing = do_replacement(regex, line, variable_format, confdata)
              missing_variables.update(missing)
              if missing:
                  confdata_useless = False
          result.append(line)
  
      return result, missing_variables, confdata_useless
  
  def do_conf_file(src: str, dst: str, confdata: 'ConfigurationData', variable_format: str,
                   encoding: str = 'utf-8') -> T.Tuple[T.Set[str], bool]:
      try:
          with open(src, encoding=encoding, newline='') as f:
              data = f.readlines()
      except Exception as e:
          raise MesonException('Could not read input file %s: %s' % (src, str(e)))
  
      (result, missing_variables, confdata_useless) = do_conf_str(data, confdata, variable_format, encoding)
      dst_tmp = dst + '~'
      try:
          with open(dst_tmp, 'w', encoding=encoding, newline='') as f:
              f.writelines(result)
      except Exception as e:
          raise MesonException('Could not write output file %s: %s' % (dst, str(e)))
      shutil.copymode(src, dst_tmp)
      replace_if_different(dst, dst_tmp)
      return missing_variables, confdata_useless
  
  CONF_C_PRELUDE = '''/*
   * Autogenerated by the Meson build system.
   * Do not edit, your changes will be lost.
   */
  
  #pragma once
  
  '''
  
  CONF_NASM_PRELUDE = '''; Autogenerated by the Meson build system.
  ; Do not edit, your changes will be lost.
  
  '''
  
  def dump_conf_header(ofilename: str, cdata: 'ConfigurationData', output_format: str) -> None:
      if output_format == 'c':
          prelude = CONF_C_PRELUDE
          prefix = '#'
      elif output_format == 'nasm':
          prelude = CONF_NASM_PRELUDE
          prefix = '%'
  
      ofilename_tmp = ofilename + '~'
      with open(ofilename_tmp, 'w', encoding='utf-8') as ofile:
          ofile.write(prelude)
          for k in sorted(cdata.keys()):
              (v, desc) = cdata.get(k)
              if desc:
                  if output_format == 'c':
                      ofile.write('/* %s */\n' % desc)
                  elif output_format == 'nasm':
                      for line in desc.split('\n'):
                          ofile.write('; %s\n' % line)
              if isinstance(v, bool):
                  if v:
                      ofile.write('%sdefine %s\n\n' % (prefix, k))
                  else:
                      ofile.write('%sundef %s\n\n' % (prefix, k))
              elif isinstance(v, (int, str)):
                  ofile.write('%sdefine %s %s\n\n' % (prefix, k, v))
              else:
                  raise MesonException('Unknown data type in configuration file entry: ' + k)
      replace_if_different(ofilename, ofilename_tmp)
  
  
  def replace_if_different(dst: str, dst_tmp: str) -> None:
      # If contents are identical, don't touch the file to prevent
      # unnecessary rebuilds.
      different = True
      try:
          with open(dst, 'rb') as f1, open(dst_tmp, 'rb') as f2:
              if f1.read() == f2.read():
                  different = False
      except FileNotFoundError:
          pass
      if different:
          os.replace(dst_tmp, dst)
      else:
          os.unlink(dst_tmp)
  
  
  @T.overload
  def unholder(item: 'ObjectHolder[_T]') -> _T: ...
  
  @T.overload
  def unholder(item: T.List['ObjectHolder[_T]']) -> T.List[_T]: ...
  
  @T.overload
  def unholder(item: T.List[_T]) -> T.List[_T]: ...
  
  @T.overload
  def unholder(item: T.List[T.Union[_T, 'ObjectHolder[_T]']]) -> T.List[_T]: ...
  
  def unholder(item):  # type: ignore  # TODO fix overload (somehow)
      """Get the held item of an object holder or list of object holders."""
      if isinstance(item, list):
          return [i.held_object if hasattr(i, 'held_object') else i for i in item]
      if hasattr(item, 'held_object'):
          return item.held_object
      return item
  
  
  def listify(item: T.Any, flatten: bool = True) -> T.List[T.Any]:
      '''
      Returns a list with all args embedded in a list if they are not a list.
      This function preserves order.
      @flatten: Convert lists of lists to a flat list
      '''
      if not isinstance(item, list):
          return [item]
      result = []  # type: T.List[T.Any]
      for i in item:
          if flatten and isinstance(i, list):
              result += listify(i, flatten=True)
          else:
              result.append(i)
      return result
  
  
  def extract_as_list(dict_object: T.Dict[_T, _U], key: _T, pop: bool = False) -> T.List[_U]:
      '''
      Extracts all values from given dict_object and listifies them.
      '''
      fetch = dict_object.get
      if pop:
          fetch = dict_object.pop
      # If there's only one key, we don't return a list with one element
      return listify(fetch(key, []), flatten=True)
  
  
  def typeslistify(item: 'T.Union[_T, T.Sequence[_T]]',
                   types: 'T.Union[T.Type[_T], T.Tuple[T.Type[_T]]]') -> T.List[_T]:
      '''
      Ensure that type(@item) is one of @types or a
      list of items all of which are of type @types
      '''
      if isinstance(item, types):
          item = T.cast(T.List[_T], [item])
      if not isinstance(item, list):
          raise MesonException('Item must be a list or one of {!r}'.format(types))
      for i in item:
          if i is not None and not isinstance(i, types):
              raise MesonException('List item must be one of {!r}'.format(types))
      return item
  
  
  def stringlistify(item: T.Union[T.Any, T.Sequence[T.Any]]) -> T.List[str]:
      return typeslistify(item, str)
  
  
  def expand_arguments(args: T.Iterable[str]) -> T.Optional[T.List[str]]:
      expended_args = []  # type: T.List[str]
      for arg in args:
          if not arg.startswith('@'):
              expended_args.append(arg)
              continue
  
          args_file = arg[1:]
          try:
              with open(args_file) as f:
                  extended_args = f.read().split()
              expended_args += extended_args
          except Exception as e:
              mlog.error('Expanding command line arguments:',  args_file, 'not found')
              mlog.exception(e)
              return None
      return expended_args
  
  
  def partition(pred: T.Callable[[_T], object], iterable: T.Iterator[_T]) -> T.Tuple[T.Iterator[_T], T.Iterator[_T]]:
      """Use a predicate to partition entries into false entries and true
      entries.
  
      >>> x, y = partition(is_odd, range(10))
      >>> (list(x), list(y))
      ([0, 2, 4, 6, 8], [1, 3, 5, 7, 9])
      """
      t1, t2 = tee(iterable)
      return filterfalse(pred, t1), filter(pred, t2)
  
  
  def Popen_safe(args: T.List[str], write: T.Optional[str] = None,
                 stdout: T.Union[T.BinaryIO, int] = subprocess.PIPE,
                 stderr: T.Union[T.BinaryIO, int] = subprocess.PIPE,
                 **kwargs: T.Any) -> T.Tuple[subprocess.Popen, str, str]:
      import locale
      encoding = locale.getpreferredencoding()
      # Redirect stdin to DEVNULL otherwise the command run by us here might mess
      # up the console and ANSI colors will stop working on Windows.
      if 'stdin' not in kwargs:
          kwargs['stdin'] = subprocess.DEVNULL
      if not sys.stdout.encoding or encoding.upper() != 'UTF-8':
          p, o, e = Popen_safe_legacy(args, write=write, stdout=stdout, stderr=stderr, **kwargs)
      else:
          p = subprocess.Popen(args, universal_newlines=True, close_fds=False,
                               stdout=stdout, stderr=stderr, **kwargs)
          o, e = p.communicate(write)
      # Sometimes the command that we run will call another command which will be
      # without the above stdin workaround, so set the console mode again just in
      # case.
      mlog.setup_console()
      return p, o, e
  
  
  def Popen_safe_legacy(args: T.List[str], write: T.Optional[str] = None,
                        stdout: T.Union[T.BinaryIO, int] = subprocess.PIPE,
                        stderr: T.Union[T.BinaryIO, int] = subprocess.PIPE,
                        **kwargs: T.Any) -> T.Tuple[subprocess.Popen, str, str]:
      p = subprocess.Popen(args, universal_newlines=False, close_fds=False,
                           stdout=stdout, stderr=stderr, **kwargs)
      input_ = None  # type: T.Optional[bytes]
      if write is not None:
          input_ = write.encode('utf-8')
      o, e = p.communicate(input_)
      if o is not None:
          if sys.stdout.encoding:
              o = o.decode(encoding=sys.stdout.encoding, errors='replace').replace('\r\n', '\n')
          else:
              o = o.decode(errors='replace').replace('\r\n', '\n')
      if e is not None:
          if sys.stderr.encoding:
              e = e.decode(encoding=sys.stderr.encoding, errors='replace').replace('\r\n', '\n')
          else:
              e = e.decode(errors='replace').replace('\r\n', '\n')
      return p, o, e
  
  
  def iter_regexin_iter(regexiter: T.Iterable[str], initer: T.Iterable[str]) -> T.Optional[str]:
      '''
      Takes each regular expression in @regexiter and tries to search for it in
      every item in @initer. If there is a match, returns that match.
      Else returns False.
      '''
      for regex in regexiter:
          for ii in initer:
              if not isinstance(ii, str):
                  continue
              match = re.search(regex, ii)
              if match:
                  return match.group()
      return None
  
  
  def _substitute_values_check_errors(command: T.List[str], values: T.Dict[str, str]) -> None:
      # Error checking
      inregex = ['@INPUT([0-9]+)?@', '@PLAINNAME@', '@BASENAME@']  # type: T.List[str]
      outregex = ['@OUTPUT([0-9]+)?@', '@OUTDIR@']                 # type: T.List[str]
      if '@INPUT@' not in values:
          # Error out if any input-derived templates are present in the command
          match = iter_regexin_iter(inregex, command)
          if match:
              m = 'Command cannot have {!r}, since no input files were specified'
              raise MesonException(m.format(match))
      else:
          if len(values['@INPUT@']) > 1:
              # Error out if @PLAINNAME@ or @BASENAME@ is present in the command
              match = iter_regexin_iter(inregex[1:], command)
              if match:
                  raise MesonException('Command cannot have {!r} when there is '
                                       'more than one input file'.format(match))
          # Error out if an invalid @INPUTnn@ template was specified
          for each in command:
              if not isinstance(each, str):
                  continue
              match2 = re.search(inregex[0], each)
              if match2 and match2.group() not in values:
                  m = 'Command cannot have {!r} since there are only {!r} inputs'
                  raise MesonException(m.format(match2.group(), len(values['@INPUT@'])))
      if '@OUTPUT@' not in values:
          # Error out if any output-derived templates are present in the command
          match = iter_regexin_iter(outregex, command)
          if match:
              m = 'Command cannot have {!r} since there are no outputs'
              raise MesonException(m.format(match))
      else:
          # Error out if an invalid @OUTPUTnn@ template was specified
          for each in command:
              if not isinstance(each, str):
                  continue
              match2 = re.search(outregex[0], each)
              if match2 and match2.group() not in values:
                  m = 'Command cannot have {!r} since there are only {!r} outputs'
                  raise MesonException(m.format(match2.group(), len(values['@OUTPUT@'])))
  
  
  def substitute_values(command: T.List[str], values: T.Dict[str, str]) -> T.List[str]:
      '''
      Substitute the template strings in the @values dict into the list of
      strings @command and return a new list. For a full list of the templates,
      see get_filenames_templates_dict()
  
      If multiple inputs/outputs are given in the @values dictionary, we
      substitute @INPUT@ and @OUTPUT@ only if they are the entire string, not
      just a part of it, and in that case we substitute *all* of them.
      '''
      # Error checking
      _substitute_values_check_errors(command, values)
      # Substitution
      outcmd = []  # type: T.List[str]
      rx_keys = [re.escape(key) for key in values if key not in ('@INPUT@', '@OUTPUT@')]
      value_rx = re.compile('|'.join(rx_keys)) if rx_keys else None
      for vv in command:
          if not isinstance(vv, str):
              outcmd.append(vv)
          elif '@INPUT@' in vv:
              inputs = values['@INPUT@']
              if vv == '@INPUT@':
                  outcmd += inputs
              elif len(inputs) == 1:
                  outcmd.append(vv.replace('@INPUT@', inputs[0]))
              else:
                  raise MesonException("Command has '@INPUT@' as part of a "
                                       "string and more than one input file")
          elif '@OUTPUT@' in vv:
              outputs = values['@OUTPUT@']
              if vv == '@OUTPUT@':
                  outcmd += outputs
              elif len(outputs) == 1:
                  outcmd.append(vv.replace('@OUTPUT@', outputs[0]))
              else:
                  raise MesonException("Command has '@OUTPUT@' as part of a "
                                       "string and more than one output file")
          # Append values that are exactly a template string.
          # This is faster than a string replace.
          elif vv in values:
              outcmd.append(values[vv])
          # Substitute everything else with replacement
          elif value_rx:
              outcmd.append(value_rx.sub(lambda m: values[m.group(0)], vv))
          else:
              outcmd.append(vv)
      return outcmd
  
  
  def get_filenames_templates_dict(inputs: T.List[str], outputs: T.List[str]) -> T.Dict[str, T.Union[str, T.List[str]]]:
      '''
      Create a dictionary with template strings as keys and values as values for
      the following templates:
  
      @INPUT@  - the full path to one or more input files, from @inputs
      @OUTPUT@ - the full path to one or more output files, from @outputs
      @OUTDIR@ - the full path to the directory containing the output files
  
      If there is only one input file, the following keys are also created:
  
      @PLAINNAME@ - the filename of the input file
      @BASENAME@ - the filename of the input file with the extension removed
  
      If there is more than one input file, the following keys are also created:
  
      @INPUT0@, @INPUT1@, ... one for each input file
  
      If there is more than one output file, the following keys are also created:
  
      @OUTPUT0@, @OUTPUT1@, ... one for each output file
      '''
      values = {}  # type: T.Dict[str, T.Union[str, T.List[str]]]
      # Gather values derived from the input
      if inputs:
          # We want to substitute all the inputs.
          values['@INPUT@'] = inputs
          for (ii, vv) in enumerate(inputs):
              # Write out @INPUT0@, @INPUT1@, ...
              values['@INPUT{}@'.format(ii)] = vv
          if len(inputs) == 1:
              # Just one value, substitute @PLAINNAME@ and @BASENAME@
              values['@PLAINNAME@'] = plain = os.path.basename(inputs[0])
              values['@BASENAME@'] = os.path.splitext(plain)[0]
      if outputs:
          # Gather values derived from the outputs, similar to above.
          values['@OUTPUT@'] = outputs
          for (ii, vv) in enumerate(outputs):
              values['@OUTPUT{}@'.format(ii)] = vv
          # Outdir should be the same for all outputs
          values['@OUTDIR@'] = os.path.dirname(outputs[0])
          # Many external programs fail on empty arguments.
          if values['@OUTDIR@'] == '':
              values['@OUTDIR@'] = '.'
      return values
  
  
  def _make_tree_writable(topdir: str) -> None:
      # Ensure all files and directories under topdir are writable
      # (and readable) by owner.
      for d, _, files in os.walk(topdir):
          os.chmod(d, os.stat(d).st_mode | stat.S_IWRITE | stat.S_IREAD)
          for fname in files:
              fpath = os.path.join(d, fname)
              if os.path.isfile(fpath):
                  os.chmod(fpath, os.stat(fpath).st_mode | stat.S_IWRITE | stat.S_IREAD)
  
  
  def windows_proof_rmtree(f: str) -> None:
      # On Windows if anyone is holding a file open you can't
      # delete it. As an example an anti virus scanner might
      # be scanning files you are trying to delete. The only
      # way to fix this is to try again and again.
      delays = [0.1, 0.1, 0.2, 0.2, 0.2, 0.5, 0.5, 1, 1, 1, 1, 2]
      # Start by making the tree wriable.
      _make_tree_writable(f)
      for d in delays:
          try:
              shutil.rmtree(f)
              return
          except FileNotFoundError:
              return
          except OSError:
              time.sleep(d)
      # Try one last time and throw if it fails.
      shutil.rmtree(f)
  
  
  def windows_proof_rm(fpath: str) -> None:
      """Like windows_proof_rmtree, but for a single file."""
      if os.path.isfile(fpath):
          os.chmod(fpath, os.stat(fpath).st_mode | stat.S_IWRITE | stat.S_IREAD)
      delays = [0.1, 0.1, 0.2, 0.2, 0.2, 0.5, 0.5, 1, 1, 1, 1, 2]
      for d in delays:
          try:
              os.unlink(fpath)
              return
          except FileNotFoundError:
              return
          except OSError:
              time.sleep(d)
      os.unlink(fpath)
  
  
  class TemporaryDirectoryWinProof(TemporaryDirectory):
      """
      Like TemporaryDirectory, but cleans things up using
      windows_proof_rmtree()
      """
  
      def __exit__(self, exc: T.Any, value: T.Any, tb: T.Any) -> None:
          try:
              super().__exit__(exc, value, tb)
          except OSError:
              windows_proof_rmtree(self.name)
  
      def cleanup(self) -> None:
          try:
              super().cleanup()
          except OSError:
              windows_proof_rmtree(self.name)
  
  
  def detect_subprojects(spdir_name: str, current_dir: str = '',
                         result: T.Optional[T.Dict[str, T.List[str]]] = None) -> T.Optional[T.Dict[str, T.List[str]]]:
      if result is None:
          result = {}
      spdir = os.path.join(current_dir, spdir_name)
      if not os.path.exists(spdir):
          return result
      for trial in glob(os.path.join(spdir, '*')):
          basename = os.path.basename(trial)
          if trial == 'packagecache':
              continue
          append_this = True
          if os.path.isdir(trial):
              detect_subprojects(spdir_name, trial, result)
          elif trial.endswith('.wrap') and os.path.isfile(trial):
              basename = os.path.splitext(basename)[0]
          else:
              append_this = False
          if append_this:
              if basename in result:
                  result[basename].append(trial)
              else:
                  result[basename] = [trial]
      return result
  
  
  def substring_is_in_list(substr: str, strlist: T.List[str]) -> bool:
      for s in strlist:
          if substr in s:
              return True
      return False
  
  
  class OrderedSet(T.MutableSet[_T]):
      """A set that preserves the order in which items are added, by first
      insertion.
      """
      def __init__(self, iterable: T.Optional[T.Iterable[_T]] = None):
          # typing.OrderedDict is new in 3.7.2, so we can't use that, but we can
          # use MutableMapping, which is fine in this case.
          self.__container = collections.OrderedDict()  # type: T.MutableMapping[_T, None]
          if iterable:
              self.update(iterable)
  
      def __contains__(self, value: object) -> bool:
          return value in self.__container
  
      def __iter__(self) -> T.Iterator[_T]:
          return iter(self.__container.keys())
  
      def __len__(self) -> int:
          return len(self.__container)
  
      def __repr__(self) -> str:
          # Don't print 'OrderedSet("")' for an empty set.
          if self.__container:
              return 'OrderedSet("{}")'.format(
                  '", "'.join(repr(e) for e in self.__container.keys()))
          return 'OrderedSet()'
  
      def __reversed__(self) -> T.Iterator[_T]:
          # Mypy is complaining that sets cant be reversed, which is true for
          # unordered sets, but this is an ordered, set so reverse() makes sense.
          return reversed(self.__container.keys())  # type: ignore
  
      def add(self, value: _T) -> None:
          self.__container[value] = None
  
      def discard(self, value: _T) -> None:
          if value in self.__container:
              del self.__container[value]
  
      def move_to_end(self, value: _T, last: bool = True) -> None:
          # Mypy does not know about move_to_end, because it is not part of MutableMapping
          self.__container.move_to_end(value, last) # type: ignore
  
      def pop(self, last: bool = True) -> _T:
          # Mypy does not know about the last argument, because it is not part of MutableMapping
          item, _ = self.__container.popitem(last)  # type: ignore
          return item
  
      def update(self, iterable: T.Iterable[_T]) -> None:
          for item in iterable:
              self.__container[item] = None
  
      def difference(self, set_: T.Union[T.Set[_T], 'OrderedSet[_T]']) -> 'OrderedSet[_T]':
          return type(self)(e for e in self if e not in set_)
  
  class BuildDirLock:
  
      def __init__(self, builddir: str) -> None:
          self.lockfilename = os.path.join(builddir, 'meson-private/meson.lock')
  
      def __enter__(self) -> None:
          self.lockfile = open(self.lockfilename, 'w')
          try:
              if have_fcntl:
                  fcntl.flock(self.lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
              elif have_msvcrt:
                  msvcrt.locking(self.lockfile.fileno(), msvcrt.LK_NBLCK, 1)
          except (BlockingIOError, PermissionError):
              self.lockfile.close()
              raise MesonException('Some other Meson process is already using this build directory. Exiting.')
  
      def __exit__(self, *args: T.Any) -> None:
          if have_fcntl:
              fcntl.flock(self.lockfile, fcntl.LOCK_UN)
          elif have_msvcrt:
              msvcrt.locking(self.lockfile.fileno(), msvcrt.LK_UNLCK, 1)
          self.lockfile.close()
  
  def relpath(path: str, start: str) -> str:
      # On Windows a relative path can't be evaluated for paths on two different
      # drives (i.e. c:\foo and f:\bar).  The only thing left to do is to use the
      # original absolute path.
      try:
          return os.path.relpath(path, start)
      except (TypeError, ValueError):
          return path
  
  def path_is_in_root(path: Path, root: Path, resolve: bool = False) -> bool:
      # Check wheter a path is within the root directory root
      try:
          if resolve:
              path.resolve().relative_to(root.resolve())
          else:
              path.relative_to(root)
      except ValueError:
          return False
      return True
  
  def relative_to_if_possible(path: Path, root: Path, resolve: bool = False) -> Path:
      try:
          if resolve:
              return path.resolve().relative_to(root.resolve())
          else:
              return path.relative_to(root)
      except ValueError:
          return path
  
  class LibType(enum.IntEnum):
  
      """Enumeration for library types."""
  
      SHARED = 0
      STATIC = 1
      PREFER_SHARED = 2
      PREFER_STATIC = 3
  
  
  class ProgressBarFallback:  # lgtm [py/iter-returns-non-self]
      '''
      Fallback progress bar implementation when tqdm is not found
  
      Since this class is not an actual iterator, but only provides a minimal
      fallback, it is safe to ignore the 'Iterator does not return self from
      __iter__ method' warning.
      '''
      def __init__(self, iterable: T.Optional[T.Iterable[str]] = None, total: T.Optional[int] = None,
                   bar_type: T.Optional[str] = None, desc: T.Optional[str] = None):
          if iterable is not None:
              self.iterable = iter(iterable)
              return
          self.total = total
          self.done = 0
          self.printed_dots = 0
          if self.total and bar_type == 'download':
              print('Download size:', self.total)
          if desc:
              print('{}: '.format(desc), end='')
  
      # Pretend to be an iterator when called as one and don't print any
      # progress
      def __iter__(self) -> T.Iterator[str]:
          return self.iterable
  
      def __next__(self) -> str:
          return next(self.iterable)
  
      def print_dot(self) -> None:
          print('.', end='')
          sys.stdout.flush()
          self.printed_dots += 1
  
      def update(self, progress: int) -> None:
          self.done += progress
          if not self.total:
              # Just print one dot per call if we don't have a total length
              self.print_dot()
              return
          ratio = int(self.done / self.total * 10)
          while self.printed_dots < ratio:
              self.print_dot()
  
      def close(self) -> None:
          print('')
  
  try:
      from tqdm import tqdm
  except ImportError:
      # ideally we would use a typing.Protocol here, but it's part of typing_extensions until 3.8
      ProgressBar = ProgressBarFallback  # type: T.Union[T.Type[ProgressBarFallback], T.Type[ProgressBarTqdm]]
  else:
      class ProgressBarTqdm(tqdm):
          def __init__(self, *args: T.Any, bar_type: T.Optional[str] = None, **kwargs: T.Any) -> None:
              if bar_type == 'download':
                  kwargs.update({'unit': 'bytes', 'leave': True})
              else:
                  kwargs.update({'leave': False})
              kwargs['ncols'] = 100
              super().__init__(*args, **kwargs)
  
      ProgressBar = ProgressBarTqdm
  
  
  def get_wine_shortpath(winecmd: T.List[str], wine_paths: T.Sequence[str]) -> str:
      """Get A short version of @wine_paths to avoid reaching WINEPATH number
      of char limit.
      """
  
      wine_paths = list(OrderedSet(wine_paths))
  
      getShortPathScript = '%s.bat' % str(uuid.uuid4()).lower()[:5]
      with open(getShortPathScript, mode='w') as f:
          f.write("@ECHO OFF\nfor %%x in (%*) do (\n echo|set /p=;%~sx\n)\n")
          f.flush()
      try:
          with open(os.devnull, 'w') as stderr:
              wine_path = subprocess.check_output(
                  winecmd +
                  ['cmd', '/C', getShortPathScript] + wine_paths,
                  stderr=stderr).decode('utf-8')
      except subprocess.CalledProcessError as e:
          print("Could not get short paths: %s" % e)
          wine_path = ';'.join(wine_paths)
      finally:
          os.remove(getShortPathScript)
      if len(wine_path) > 2048:
          raise MesonException(
              'WINEPATH size {} > 2048'
              ' this will cause random failure.'.format(
                  len(wine_path)))
  
      return wine_path.strip(';')
  
  
  def run_once(func: T.Callable[..., _T]) -> T.Callable[..., _T]:
      ret = []  # type: T.List[_T]
  
      @wraps(func)
      def wrapper(*args: T.Any, **kwargs: T.Any) -> _T:
          if ret:
              return ret[0]
  
          val = func(*args, **kwargs)
          ret.append(val)
          return val
  
      return wrapper
  
  
  class OptionProxy(T.Generic[_T]):
      def __init__(self, value: _T, choices: T.Optional[T.List[str]] = None):
          self.value = value
          self.choices = choices
  
      def set_value(self, v: _T) -> None:
          # XXX: should this be an error
          self.value = v
  
  
  class OptionOverrideProxy(collections.abc.MutableMapping):
  
      '''Mimic an option list but transparently override selected option
      values.
      '''
  
      # TODO: the typing here could be made more explicit using a TypeDict from
      # python 3.8 or typing_extensions
  
      def __init__(self, overrides: T.Dict['OptionKey', T.Any], *options: 'KeyedOptionDictType'):
          self.overrides = overrides.copy()
          self.options: T.Dict['OptionKey', UserOption] = {}
          for o in options:
              self.options.update(o)
  
      def __getitem__(self, key: 'OptionKey') -> T.Union['UserOption', OptionProxy]:
          if key in self.options:
              opt = self.options[key]
              if key in self.overrides:
                  return OptionProxy(opt.validate_value(self.overrides[key]), getattr(opt, 'choices', None))
              return opt
          raise KeyError('Option not found', key)
  
      def __setitem__(self, key: 'OptionKey', value: T.Union['UserOption', OptionProxy]) -> None:
          self.overrides[key] = value.value
  
      def __delitem__(self, key: 'OptionKey') -> None:
          del self.overrides[key]
  
      def __iter__(self) -> T.Iterator['OptionKey']:
          return iter(self.options)
  
      def __len__(self) -> int:
          return len(self.options)
  
      def copy(self) -> 'OptionOverrideProxy':
          return OptionOverrideProxy(self.overrides.copy(), self.options.copy())
  
  
  class OptionType(enum.Enum):
  
      """Enum used to specify what kind of argument a thing is."""
  
      BUILTIN = 0
      BASE = 1
      COMPILER = 2
      PROJECT = 3
      BACKEND = 4
  
  # This is copied from coredata. There is no way to share this, because this
  # is used in the OptionKey constructor, and the coredata lists are
  # OptionKeys...
  _BUILTIN_NAMES = {
      'prefix',
      'bindir',
      'datadir',
      'includedir',
      'infodir',
      'libdir',
      'libexecdir',
      'localedir',
      'localstatedir',
      'mandir',
      'sbindir',
      'sharedstatedir',
      'sysconfdir',
      'auto_features',
      'backend',
      'buildtype',
      'debug',
      'default_library',
      'errorlogs',
      'install_umask',
      'layout',
      'optimization',
      'stdsplit',
      'strip',
      'unity',
      'unity_size',
      'warning_level',
      'werror',
      'wrap_mode',
      'force_fallback_for',
      'pkg_config_path',
      'cmake_prefix_path',
  }
  
  
  def _classify_argument(key: 'OptionKey') -> OptionType:
      """Classify arguments into groups so we know which dict to assign them to."""
  
      if key.name.startswith('b_'):
          assert key.machine is MachineChoice.HOST, str(key)
          return OptionType.BASE
      elif key.lang is not None:
          return OptionType.COMPILER
      elif key.name in _BUILTIN_NAMES:
          return OptionType.BUILTIN
      elif key.name.startswith('backend_'):
          assert key.machine is MachineChoice.HOST, str(key)
          return OptionType.BACKEND
      else:
          assert key.machine is MachineChoice.HOST, str(key)
          return OptionType.PROJECT
  
  
  @total_ordering
  class OptionKey:
  
      """Represents an option key in the various option dictionaries.
  
      This provides a flexible, powerful way to map option names from their
      external form (things like subproject:build.option) to something that
      internally easier to reason about and produce.
      """
  
      __slots__ = ['name', 'subproject', 'machine', 'lang', '_hash', 'type']
  
      name: str
      subproject: str
      machine: MachineChoice
      lang: T.Optional[str]
      _hash: int
      type: OptionType
  
      def __init__(self, name: str, subproject: str = '',
                   machine: MachineChoice = MachineChoice.HOST,
                   lang: T.Optional[str] = None, _type: T.Optional[OptionType] = None):
          # the _type option to the constructor is kinda private. We want to be
          # able tos ave the state and avoid the lookup function when
          # pickling/unpickling, but we need to be able to calculate it when
          # constructing a new OptionKey
          object.__setattr__(self, 'name', name)
          object.__setattr__(self, 'subproject', subproject)
          object.__setattr__(self, 'machine', machine)
          object.__setattr__(self, 'lang', lang)
          object.__setattr__(self, '_hash', hash((name, subproject, machine, lang)))
          if _type is None:
              _type = _classify_argument(self)
          object.__setattr__(self, 'type', _type)
  
      def __setattr__(self, key: str, value: T.Any) -> None:
          raise AttributeError('OptionKey instances do not support mutation.')
  
      def __getstate__(self) -> T.Dict[str, T.Any]:
          return {
              'name': self.name,
              'subproject': self.subproject,
              'machine': self.machine,
              'lang': self.lang,
              '_type': self.type,
          }
  
      def __setstate__(self, state: T.Dict[str, T.Any]) -> None:
          """De-serialize the state of a pickle.
  
          This is very clever. __init__ is not a constructor, it's an
          initializer, therefore it's safe to call more than once. We create a
          state in the custom __getstate__ method, which is valid to pass
          splatted to the initializer.
          """
          # Mypy doesn't like this, because it's so clever.
          self.__init__(**state)  # type: ignore
  
      def __hash__(self) -> int:
          return self._hash
  
      def __eq__(self, other: object) -> bool:
          if isinstance(other, OptionKey):
              return (
                  self.name == other.name and
                  self.subproject == other.subproject and
                  self.machine is other.machine and
                  self.lang == other.lang)
          return NotImplemented
  
      def __lt__(self, other: object) -> bool:
          if isinstance(other, OptionKey):
              return (
                  self.name < other.name and
                  self.subproject < other.subproject and
                  self.machine < other.machine and
                  self.lang < other.lang)
          return NotImplemented
  
      def __str__(self) -> str:
          out = self.name
          if self.lang:
              out = f'{self.lang}_{out}'
          if self.machine is MachineChoice.BUILD:
              out = f'build.{out}'
          if self.subproject:
              out = f'{self.subproject}:{out}'
          return out
  
      def __repr__(self) -> str:
          return f'OptionKey({repr(self.name)}, {repr(self.subproject)}, {repr(self.machine)}, {repr(self.lang)})'
  
      @classmethod
      def from_string(cls, raw: str) -> 'OptionKey':
          """Parse the raw command line format into a three part tuple.
  
          This takes strings like `mysubproject:build.myoption` and Creates an
          OptionKey out of them.
          """
  
          try:
              subproject, raw2 = raw.split(':')
          except ValueError:
              subproject, raw2 = '', raw
  
          if raw2.startswith('build.'):
              raw3 = raw2.lstrip('build.')
              for_machine = MachineChoice.BUILD
          else:
              raw3 = raw2
              for_machine = MachineChoice.HOST
  
          from .compilers import all_languages
          if any(raw3.startswith(f'{l}_') for l in all_languages):
              lang, opt = raw3.split('_', 1)
          else:
              lang, opt = None, raw3
          assert ':' not in opt
          assert 'build.' not in opt
  
          return cls(opt, subproject, for_machine, lang)
  
      def evolve(self, name: T.Optional[str] = None, subproject: T.Optional[str] = None,
                 machine: T.Optional[MachineChoice] = None, lang: T.Optional[str] = '') -> 'OptionKey':
          """Create a new copy of this key, but with alterted members.
  
          For example:
          >>> a = OptionKey('foo', '', MachineChoice.Host)
          >>> b = OptionKey('foo', 'bar', MachineChoice.Host)
          >>> b == a.evolve(subproject='bar')
          True
          """
          # We have to be a little clever with lang here, because lang is valid
          # as None, for non-compiler options
          return OptionKey(
              name if name is not None else self.name,
              subproject if subproject is not None else self.subproject,
              machine if machine is not None else self.machine,
              lang if lang != '' else self.lang,
          )
  
      def as_root(self) -> 'OptionKey':
          """Convenience method for key.evolve(subproject='')."""
          return self.evolve(subproject='')
  
      def as_build(self) -> 'OptionKey':
          """Convenience method for key.evolve(machine=MachinceChoice.BUILD)."""
          return self.evolve(machine=MachineChoice.BUILD)
  
      def as_host(self) -> 'OptionKey':
          """Convenience method for key.evolve(machine=MachinceChoice.HOST)."""
          return self.evolve(machine=MachineChoice.HOST)
  
      def is_backend(self) -> bool:
          """Convenience method to check if this is a backend option."""
          return self.type is OptionType.BACKEND
  
      def is_builtin(self) -> bool:
          """Convenience method to check if this is a builtin option."""
          return self.type is OptionType.BUILTIN
  
      def is_compiler(self) -> bool:
          """Convenience method to check if this is a builtin option."""
          return self.type is OptionType.COMPILER
  
      def is_project(self) -> bool:
          """Convenience method to check if this is a project option."""
          return self.type is OptionType.PROJECT
  
      def is_base(self) -> bool:
          """Convenience method to check if this is a base option."""
          return self.type is OptionType.BASE