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# Module 'ntpath' -- common operations on WinNT/Win95 pathnames
"""Common pathname manipulations, WindowsNT/95 version.
Instead of importing this module directly, import os and refer to this
module as os.path.
"""
import os
import sys
import stat
import genericpath
from genericpath import *
__all__ = ["normcase","isabs","join","splitdrive","split","splitext",
"basename","dirname","commonprefix","getsize","getmtime",
"getatime","getctime", "islink","exists","lexists","isdir","isfile",
"ismount", "expanduser","expandvars","normpath","abspath",
"splitunc","curdir","pardir","sep","pathsep","defpath","altsep",
"extsep","devnull","realpath","supports_unicode_filenames","relpath"]
# strings representing various path-related bits and pieces
curdir = '.'
pardir = '..'
extsep = '.'
sep = '\\'
pathsep = ';'
altsep = '/'
defpath = '.;C:\\bin'
if 'ce' in sys.builtin_module_names:
defpath = '\\Windows'
elif 'os2' in sys.builtin_module_names:
# OS/2 w/ VACPP
altsep = '/'
devnull = 'nul'
# Normalize the case of a pathname and map slashes to backslashes.
# Other normalizations (such as optimizing '../' away) are not done
# (this is done by normpath).
def normcase(s):
"""Normalize case of pathname.
Makes all characters lowercase and all slashes into backslashes."""
return s.replace("/", "\\").lower()
# Return whether a path is absolute.
# Trivial in Posix, harder on the Mac or MS-DOS.
# For DOS it is absolute if it starts with a slash or backslash (current
# volume), or if a pathname after the volume letter and colon / UNC resource
# starts with a slash or backslash.
def isabs(s):
"""Test whether a path is absolute"""
s = splitdrive(s)[1]
return s != '' and s[:1] in '/\\'
# Join two (or more) paths.
def join(a, *p):
"""Join two or more pathname components, inserting "\\" as needed.
If any component is an absolute path, all previous path components
will be discarded."""
path = a
for b in p:
b_wins = 0 # set to 1 iff b makes path irrelevant
if path == "":
b_wins = 1
elif isabs(b):
# This probably wipes out path so far. However, it's more
# complicated if path begins with a drive letter:
# 1. join('c:', '/a') == 'c:/a'
# 2. join('c:/', '/a') == 'c:/a'
# But
# 3. join('c:/a', '/b') == '/b'
# 4. join('c:', 'd:/') = 'd:/'
# 5. join('c:/', 'd:/') = 'd:/'
if path[1:2] != ":" or b[1:2] == ":":
# Path doesn't start with a drive letter, or cases 4 and 5.
b_wins = 1
# Else path has a drive letter, and b doesn't but is absolute.
elif len(path) > 3 or (len(path) == 3 and
path[-1] not in "/\\"):
# case 3
b_wins = 1
if b_wins:
path = b
else:
# Join, and ensure there's a separator.
assert len(path) > 0
if path[-1] in "/\\":
if b and b[0] in "/\\":
path += b[1:]
else:
path += b
elif path[-1] == ":":
path += b
elif b:
if b[0] in "/\\":
path += b
else:
path += "\\" + b
else:
# path is not empty and does not end with a backslash,
# but b is empty; since, e.g., split('a/') produces
# ('a', ''), it's best if join() adds a backslash in
# this case.
path += '\\'
return path
# Split a path in a drive specification (a drive letter followed by a
# colon) and the path specification.
# It is always true that drivespec + pathspec == p
def splitdrive(p):
"""Split a pathname into drive and path specifiers. Returns a 2-tuple
"(drive,path)"; either part may be empty"""
if p[1:2] == ':':
return p[0:2], p[2:]
return '', p
# Parse UNC paths
def splitunc(p):
"""Split a pathname into UNC mount point and relative path specifiers.
Return a 2-tuple (unc, rest); either part may be empty.
If unc is not empty, it has the form '//host/mount' (or similar
using backslashes). unc+rest is always the input path.
Paths containing drive letters never have an UNC part.
"""
if p[1:2] == ':':
return '', p # Drive letter present
firstTwo = p[0:2]
if firstTwo == '//' or firstTwo == '\\\\':
# is a UNC path:
# vvvvvvvvvvvvvvvvvvvv equivalent to drive letter
# \\machine\mountpoint\directories...
# directory ^^^^^^^^^^^^^^^
normp = normcase(p)
index = normp.find('\\', 2)
if index == -1:
##raise RuntimeError, 'illegal UNC path: "' + p + '"'
return ("", p)
index = normp.find('\\', index + 1)
if index == -1:
index = len(p)
return p[:index], p[index:]
return '', p
# Split a path in head (everything up to the last '/') and tail (the
# rest). After the trailing '/' is stripped, the invariant
# join(head, tail) == p holds.
# The resulting head won't end in '/' unless it is the root.
def split(p):
"""Split a pathname.
Return tuple (head, tail) where tail is everything after the final slash.
Either part may be empty."""
d, p = splitdrive(p)
# set i to index beyond p's last slash
i = len(p)
while i and p[i-1] not in '/\\':
i = i - 1
head, tail = p[:i], p[i:] # now tail has no slashes
# remove trailing slashes from head, unless it's all slashes
head2 = head
while head2 and head2[-1] in '/\\':
head2 = head2[:-1]
head = head2 or head
return d + head, tail
# Split a path in root and extension.
# The extension is everything starting at the last dot in the last
# pathname component; the root is everything before that.
# It is always true that root + ext == p.
def splitext(p):
return genericpath._splitext(p, sep, altsep, extsep)
splitext.__doc__ = genericpath._splitext.__doc__
# Return the tail (basename) part of a path.
def basename(p):
"""Returns the final component of a pathname"""
return split(p)[1]
# Return the head (dirname) part of a path.
def dirname(p):
"""Returns the directory component of a pathname"""
return split(p)[0]
# Is a path a symbolic link?
# This will always return false on systems where posix.lstat doesn't exist.
def islink(path):
"""Test for symbolic link.
On WindowsNT/95 and OS/2 always returns false
"""
return False
# alias exists to lexists
lexists = exists
# Is a path a mount point? Either a root (with or without drive letter)
# or an UNC path with at most a / or \ after the mount point.
def ismount(path):
"""Test whether a path is a mount point (defined as root of drive)"""
unc, rest = splitunc(path)
if unc:
return rest in ("", "/", "\\")
p = splitdrive(path)[1]
return len(p) == 1 and p[0] in '/\\'
# Expand paths beginning with '~' or '~user'.
# '~' means $HOME; '~user' means that user's home directory.
# If the path doesn't begin with '~', or if the user or $HOME is unknown,
# the path is returned unchanged (leaving error reporting to whatever
# function is called with the expanded path as argument).
# See also module 'glob' for expansion of *, ? and [...] in pathnames.
# (A function should also be defined to do full *sh-style environment
# variable expansion.)
def expanduser(path):
"""Expand ~ and ~user constructs.
If user or $HOME is unknown, do nothing."""
if path[:1] != '~':
return path
i, n = 1, len(path)
while i < n and path[i] not in '/\\':
i = i + 1
if 'HOME' in os.environ:
userhome = os.environ['HOME']
elif 'USERPROFILE' in os.environ:
userhome = os.environ['USERPROFILE']
elif not 'HOMEPATH' in os.environ:
return path
else:
try:
drive = os.environ['HOMEDRIVE']
except KeyError:
drive = ''
userhome = join(drive, os.environ['HOMEPATH'])
if i != 1: #~user
userhome = join(dirname(userhome), path[1:i])
return userhome + path[i:]
# Expand paths containing shell variable substitutions.
# The following rules apply:
# - no expansion within single quotes
# - '$$' is translated into '$'
# - '%%' is translated into '%' if '%%' are not seen in %var1%%var2%
# - ${varname} is accepted.
# - $varname is accepted.
# - %varname% is accepted.
# - varnames can be made out of letters, digits and the characters '_-'
# (though is not verifed in the ${varname} and %varname% cases)
# XXX With COMMAND.COM you can use any characters in a variable name,
# XXX except '^|<>='.
def expandvars(path):
"""Expand shell variables of the forms $var, ${var} and %var%.
Unknown variables are left unchanged."""
if '$' not in path and '%' not in path:
return path
import string
varchars = string.ascii_letters + string.digits + '_-'
res = ''
index = 0
pathlen = len(path)
while index < pathlen:
c = path[index]
if c == '\'': # no expansion within single quotes
path = path[index + 1:]
pathlen = len(path)
try:
index = path.index('\'')
res = res + '\'' + path[:index + 1]
except ValueError:
res = res + path
index = pathlen - 1
elif c == '%': # variable or '%'
if path[index + 1:index + 2] == '%':
res = res + c
index = index + 1
else:
path = path[index+1:]
pathlen = len(path)
try:
index = path.index('%')
except ValueError:
res = res + '%' + path
index = pathlen - 1
else:
var = path[:index]
if var in os.environ:
res = res + os.environ[var]
else:
res = res + '%' + var + '%'
elif c == '$': # variable or '$$'
if path[index + 1:index + 2] == '$':
res = res + c
index = index + 1
elif path[index + 1:index + 2] == '{':
path = path[index+2:]
pathlen = len(path)
try:
index = path.index('}')
var = path[:index]
if var in os.environ:
res = res + os.environ[var]
else:
res = res + '${' + var + '}'
except ValueError:
res = res + '${' + path
index = pathlen - 1
else:
var = ''
index = index + 1
c = path[index:index + 1]
while c != '' and c in varchars:
var = var + c
index = index + 1
c = path[index:index + 1]
if var in os.environ:
res = res + os.environ[var]
else:
res = res + '$' + var
if c != '':
index = index - 1
else:
res = res + c
index = index + 1
return res
# Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A\B.
# Previously, this function also truncated pathnames to 8+3 format,
# but as this module is called "ntpath", that's obviously wrong!
def normpath(path):
"""Normalize path, eliminating double slashes, etc."""
path = path.replace("/", "\\")
prefix, path = splitdrive(path)
# We need to be careful here. If the prefix is empty, and the path starts
# with a backslash, it could either be an absolute path on the current
# drive (\dir1\dir2\file) or a UNC filename (\\server\mount\dir1\file). It
# is therefore imperative NOT to collapse multiple backslashes blindly in
# that case.
# The code below preserves multiple backslashes when there is no drive
# letter. This means that the invalid filename \\\a\b is preserved
# unchanged, where a\\\b is normalised to a\b. It's not clear that there
# is any better behaviour for such edge cases.
if prefix == '':
# No drive letter - preserve initial backslashes
while path[:1] == "\\":
prefix = prefix + "\\"
path = path[1:]
else:
# We have a drive letter - collapse initial backslashes
if path.startswith("\\"):
prefix = prefix + "\\"
path = path.lstrip("\\")
comps = path.split("\\")
i = 0
while i < len(comps):
if comps[i] in ('.', ''):
del comps[i]
elif comps[i] == '..':
if i > 0 and comps[i-1] != '..':
del comps[i-1:i+1]
i -= 1
elif i == 0 and prefix.endswith("\\"):
del comps[i]
else:
i += 1
else:
i += 1
# If the path is now empty, substitute '.'
if not prefix and not comps:
comps.append('.')
return prefix + "\\".join(comps)
# Return an absolute path.
try:
from nt import _getfullpathname
except ImportError: # not running on Windows - mock up something sensible
def abspath(path):
"""Return the absolute version of a path."""
if not isabs(path):
path = join(os.getcwd(), path)
return normpath(path)
else: # use native Windows method on Windows
def abspath(path):
"""Return the absolute version of a path."""
if path: # Empty path must return current working directory.
try:
path = _getfullpathname(path)
except WindowsError:
pass # Bad path - return unchanged.
else:
path = os.getcwd()
return normpath(path)
# realpath is a no-op on systems without islink support
realpath = abspath
# Win9x family and earlier have no Unicode filename support.
supports_unicode_filenames = (hasattr(sys, "getwindowsversion") and
sys.getwindowsversion()[3] >= 2)
def relpath(path, start=curdir):
"""Return a relative version of a path"""
if not path:
raise ValueError("no path specified")
start_list = abspath(start).split(sep)
path_list = abspath(path).split(sep)
if start_list[0].lower() != path_list[0].lower():
unc_path, rest = splitunc(path)
unc_start, rest = splitunc(start)
if bool(unc_path) ^ bool(unc_start):
raise ValueError("Cannot mix UNC and non-UNC paths (%s and %s)"
% (path, start))
else:
raise ValueError("path is on drive %s, start on drive %s"
% (path_list[0], start_list[0]))
# Work out how much of the filepath is shared by start and path.
for i in range(min(len(start_list), len(path_list))):
if start_list[i].lower() != path_list[i].lower():
break
else:
i += 1
rel_list = [pardir] * (len(start_list)-i) + path_list[i:]
if not rel_list:
return curdir
return join(*rel_list)