150 lines
6.6 KiB
Python
150 lines
6.6 KiB
Python
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#!/usr/bin/env python
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""" Which - locate a command
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* adapted from Brian Curtin's http://bugs.python.org/file15381/shutil_which.patch
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* see http://bugs.python.org/issue444582
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* uses ``PATHEXT`` on Windows
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* searches current directory before ``PATH`` on Windows,
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but not before an explicitly passed path
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* accepts both string or iterable for an explicitly passed path, or pathext
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* accepts an explicitly passed empty path, or pathext (either '' or [])
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* does not search ``PATH`` for files that have a path specified in their name already
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* moved defpath and defpathext lists initialization to module level,
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instead of initializing them on each function call
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* changed interface: which_files() returns generator, which() returns first match,
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or raises IOError(errno.ENOENT)
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.. function:: which_files(file [, mode=os.F_OK | os.X_OK[, path=None[, pathext=None]]])
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Return a generator which yields full paths in which the *file* name exists
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in a directory that is part of the file name, or on *path*,
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and has the given *mode*.
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By default, *mode* matches an inclusive OR of os.F_OK and os.X_OK - an
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existing executable file.
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The *path* is, by default, the ``PATH`` variable on the platform,
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or the string/iterable passed in as *path*.
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In the event that a ``PATH`` variable is not found, :const:`os.defpath` is used.
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On Windows, a current directory is searched before using the ``PATH`` variable,
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but not before an explicitly passed *path*.
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The *pathext* is only used on Windows to match files with given extensions appended as well.
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It defaults to the ``PATHEXT`` variable, or the string/iterable passed in as *pathext*.
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In the event that a ``PATHEXT`` variable is not found,
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default value for Windows XP/Vista is used.
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The command is always searched without extension first,
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even when *pathext* is explicitly passed.
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.. function:: which(file [, mode=os.F_OK | os.X_OK[, path=None[, pathext=None]]])
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Return first match generated by which_files(file, mode, path, pathext),
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or raise IOError(errno.ENOENT).
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"""
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__docformat__ = 'restructuredtext en'
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__all__ = 'which which_files pathsep defpath defpathext F_OK R_OK W_OK X_OK'.split()
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import sys
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from os import access, defpath, pathsep, environ, F_OK, R_OK, W_OK, X_OK
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from os.path import exists, dirname, split, join
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ENOENT = 2
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windows = sys.platform.startswith('win')
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defpath = environ.get('PATH', defpath).split(pathsep)
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if windows:
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defpath.insert(0, '.') # can insert without checking, when duplicates are removed
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# given the quite usual mess in PATH on Windows, let's rather remove duplicates
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seen = set()
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defpath = [dir for dir in defpath if dir.lower() not in seen and not seen.add(dir.lower())]
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del seen
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defpathext = [''] + environ.get('PATHEXT',
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'.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC').lower().split(pathsep)
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else:
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defpathext = ['']
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def which_files(file, mode=F_OK | X_OK, path=None, pathext=None):
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""" Locate a file in a path supplied as a part of the file name,
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or the user's path, or a supplied path.
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The function yields full paths (not necessarily absolute paths),
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in which the given file name matches an existing file in a directory on the path.
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>>> def test_which(expected, *args, **argd):
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... result = list(which_files(*args, **argd))
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... assert result == expected, 'which_files: %s != %s' % (result, expected)
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...
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... try:
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... result = [ which(*args, **argd) ]
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... except IOError:
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... result = []
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... assert result[:1] == expected[:1], 'which: %s != %s' % (result[:1], expected[:1])
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>>> if windows: cmd = environ['COMSPEC']
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>>> if windows: test_which([cmd], 'cmd')
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>>> if windows: test_which([cmd], 'cmd.exe')
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>>> if windows: test_which([cmd], 'cmd', path=dirname(cmd))
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>>> if windows: test_which([cmd], 'cmd', pathext='.exe')
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>>> if windows: test_which([cmd], cmd)
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>>> if windows: test_which([cmd], cmd, path='<nonexistent>')
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>>> if windows: test_which([cmd], cmd, pathext='<nonexistent>')
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>>> if windows: test_which([cmd], cmd[:-4])
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>>> if windows: test_which([cmd], cmd[:-4], path='<nonexistent>')
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>>> if windows: test_which([], 'cmd', path='<nonexistent>')
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>>> if windows: test_which([], 'cmd', pathext='<nonexistent>')
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>>> if windows: test_which([], '<nonexistent>/cmd')
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>>> if windows: test_which([], cmd[:-4], pathext='<nonexistent>')
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>>> if not windows: sh = '/bin/sh'
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>>> if not windows: test_which([sh], 'sh')
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>>> if not windows: test_which([sh], 'sh', path=dirname(sh))
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>>> if not windows: test_which([sh], 'sh', pathext='<nonexistent>')
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>>> if not windows: test_which([sh], sh)
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>>> if not windows: test_which([sh], sh, path='<nonexistent>')
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>>> if not windows: test_which([sh], sh, pathext='<nonexistent>')
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>>> if not windows: test_which([], 'sh', mode=W_OK) # not running as root, are you?
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>>> if not windows: test_which([], 'sh', path='<nonexistent>')
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>>> if not windows: test_which([], '<nonexistent>/sh')
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"""
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filepath, file = split(file)
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if filepath:
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path = (filepath,)
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elif path is None:
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path = defpath
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elif isinstance(path, str):
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path = path.split(pathsep)
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if pathext is None:
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pathext = defpathext
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elif isinstance(pathext, str):
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pathext = pathext.split(pathsep)
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if not '' in pathext:
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pathext.insert(0, '') # always check command without extension, even for custom pathext
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for dir in path:
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basepath = join(dir, file)
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for ext in pathext:
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fullpath = basepath + ext
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if exists(fullpath) and access(fullpath, mode):
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yield fullpath
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def which(file, mode=F_OK | X_OK, path=None, pathext=None):
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""" Locate a file in a path supplied as a part of the file name,
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or the user's path, or a supplied path.
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The function returns full path (not necessarily absolute path),
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in which the given file name matches an existing file in a directory on the path,
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or raises IOError(errno.ENOENT).
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>>> # for doctest see which_files()
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"""
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path = next(which_files(file, mode, path, pathext), None)
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if path is None:
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raise IOError(ENOENT, '%s not found' % (mode & X_OK and 'command' or 'file'), file)
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return path
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if __name__ == '__main__':
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import doctest
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doctest.testmod()
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