lldb/third_party/Python/module/ptyprocess-0.6.0/ptyprocess/util.py

   1 try:
   2     from shutil import which  # Python >= 3.3
   3 except ImportError:
   4     import os, sys
   5
   6     # This is copied from Python 3.4.1
   7     def which(cmd, mode=os.F_OK | os.X_OK, path=None):
   8         """Given a command, mode, and a PATH string, return the path which
   9         conforms to the given mode on the PATH, or None if there is no such
  10         file.
  11
  12         `mode` defaults to os.F_OK | os.X_OK. `path` defaults to the result
  13         of os.environ.get("PATH"), or can be overridden with a custom search
  14         path.
  15
  16         """
  17         # Check that a given file can be accessed with the correct mode.
  18         # Additionally check that `file` is not a directory, as on Windows
  19         # directories pass the os.access check.
  20         def _access_check(fn, mode):
  21             return (os.path.exists(fn) and os.access(fn, mode)
  22                     and not os.path.isdir(fn))
  23
  24         # If we're given a path with a directory part, look it up directly rather
  25         # than referring to PATH directories. This includes checking relative to the
  26         # current directory, e.g. ./script
  27         if os.path.dirname(cmd):
  28             if _access_check(cmd, mode):
  29                 return cmd
  30             return None
  31
  32         if path is None:
  33             path = os.environ.get("PATH", os.defpath)
  34         if not path:
  35             return None
  36         path = path.split(os.pathsep)
  37
  38         if sys.platform == "win32":
  39             # The current directory takes precedence on Windows.
  40             if not os.curdir in path:
  41                 path.insert(0, os.curdir)
  42
  43             # PATHEXT is necessary to check on Windows.
  44             pathext = os.environ.get("PATHEXT", "").split(os.pathsep)
  45             # See if the given file matches any of the expected path extensions.
  46             # This will allow us to short circuit when given "python.exe".
  47             # If it does match, only test that one, otherwise we have to try
  48             # others.
  49             if any(cmd.lower().endswith(ext.lower()) for ext in pathext):
  50                 files = [cmd]
  51             else:
  52                 files = [cmd + ext for ext in pathext]
  53         else:
  54             # On other platforms you don't have things like PATHEXT to tell you
  55             # what file suffixes are executable, so just pass on cmd as-is.
  56             files = [cmd]
  57
  58         seen = set()
  59         for dir in path:
  60             normdir = os.path.normcase(dir)
  61             if not normdir in seen:
  62                 seen.add(normdir)
  63                 for thefile in files:
  64                     name = os.path.join(dir, thefile)
  65                     if _access_check(name, mode):
  66                         return name
  67         return None
  68
  69
  70 class PtyProcessError(Exception):
  71     """Generic error class for this package."""