ref: 8561a843070582d48ef7f99e1138941c3509975f
dir: /sys/lib/python/os2emxpath.py/
# Module 'os2emxpath' -- common operations on OS/2 pathnames
"""Common pathname manipulations, OS/2 EMX version.
Instead of importing this module directly, import os and refer to this
module as os.path.
"""
import os
import stat
__all__ = ["normcase","isabs","join","splitdrive","split","splitext",
"basename","dirname","commonprefix","getsize","getmtime",
"getatime","getctime", "islink","exists","lexists","isdir","isfile",
"ismount","walk","expanduser","expandvars","normpath","abspath",
"splitunc","curdir","pardir","sep","pathsep","defpath","altsep",
"extsep","devnull","realpath","supports_unicode_filenames"]
# strings representing various path-related bits and pieces
curdir = '.'
pardir = '..'
extsep = '.'
sep = '/'
altsep = '\\'
pathsep = ';'
defpath = '.;C:\\bin'
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 altseps into seps."""
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 sep as needed"""
path = a
for b in p:
if isabs(b):
path = b
elif path == '' or path[-1:] in '/\\:':
path = path + b
else:
path = path + '/' + b
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 == '/' * 2 or firstTwo == '\\' * 2:
# 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):
"""Split the extension from a pathname.
Extension is everything from the last dot to the end.
Return (root, ext), either part may be empty."""
root, ext = '', ''
for c in p:
if c in ['/','\\']:
root, ext = root + ext + c, ''
elif c == '.':
if ext:
root, ext = root + ext, c
else:
ext = c
elif ext:
ext = ext + c
else:
root = root + c
return root, ext
# 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]
# Return the longest prefix of all list elements.
def commonprefix(m):
"Given a list of pathnames, returns the longest common leading component"
if not m: return ''
s1 = min(m)
s2 = max(m)
n = min(len(s1), len(s2))
for i in xrange(n):
if s1[i] != s2[i]:
return s1[:i]
return s1[:n]
# Get size, mtime, atime of files.
def getsize(filename):
"""Return the size of a file, reported by os.stat()"""
return os.stat(filename).st_size
def getmtime(filename):
"""Return the last modification time of a file, reported by os.stat()"""
return os.stat(filename).st_mtime
def getatime(filename):
"""Return the last access time of a file, reported by os.stat()"""
return os.stat(filename).st_atime
def getctime(filename):
"""Return the creation time of a file, reported by os.stat()."""
return os.stat(filename).st_ctime
# 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 OS/2 always returns false"""
return False
# Does a path exist?
# This is false for dangling symbolic links.
def exists(path):
"""Test whether a path exists"""
try:
st = os.stat(path)
except os.error:
return False
return True
lexists = exists
# Is a path a directory?
def isdir(path):
"""Test whether a path is a directory"""
try:
st = os.stat(path)
except os.error:
return False
return stat.S_ISDIR(st.st_mode)
# Is a path a regular file?
# This follows symbolic links, so both islink() and isdir() can be true
# for the same path.
def isfile(path):
"""Test whether a path is a regular file"""
try:
st = os.stat(path)
except os.error:
return False
return stat.S_ISREG(st.st_mode)
# 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 '/\\'
# Directory tree walk.
# For each directory under top (including top itself, but excluding
# '.' and '..'), func(arg, dirname, filenames) is called, where
# dirname is the name of the directory and filenames is the list
# of files (and subdirectories etc.) in the directory.
# The func may modify the filenames list, to implement a filter,
# or to impose a different order of visiting.
def walk(top, func, arg):
"""Directory tree walk whth callback function.
walk(top, func, arg) calls func(arg, d, files) for each directory d
in the tree rooted at top (including top itself); files is a list
of all the files and subdirs in directory d."""
try:
names = os.listdir(top)
except os.error:
return
func(arg, top, names)
exceptions = ('.', '..')
for name in names:
if name not in exceptions:
name = join(top, name)
if isdir(name):
walk(name, func, arg)
# 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 i == 1:
if 'HOME' in os.environ:
userhome = os.environ['HOME']
elif not 'HOMEPATH' in os.environ:
return path
else:
try:
drive = os.environ['HOMEDRIVE']
except KeyError:
drive = ''
userhome = join(drive, os.environ['HOMEPATH'])
else:
return path
return userhome + path[i:]
# Expand paths containing shell variable substitutions.
# The following rules apply:
# - no expansion within single quotes
# - no escape character, except for '$$' which is translated into '$'
# - ${varname} is accepted.
# - varnames can be made out of letters, digits and the character '_'
# XXX With COMMAND.COM you can use any characters in a variable name,
# XXX except '^|<>='.
def expandvars(path):
"""Expand shell variables of form $var and ${var}.
Unknown variables are left unchanged."""
if '$' not in path:
return path
import string
varchars = string.letters + string.digits + '_-'
res = ''
index = 0
pathlen = len(path)
while index < pathlen:
c = path[index]
if c == '\'': # no expansion within single quotes
path = path[index + 1:]
pathlen = len(path)
try:
index = path.index('\'')
res = res + '\'' + path[:index + 1]
except ValueError:
res = res + path
index = pathlen - 1
elif c == '$': # variable or '$$'
if path[index + 1:index + 2] == '$':
res = res + c
index = index + 1
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]
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]
if c != '':
res = res + c
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.
def normpath(path):
"""Normalize path, eliminating double slashes, etc."""
path = path.replace('\\', '/')
prefix, path = splitdrive(path)
while path[:1] == '/':
prefix = prefix + '/'
path = path[1:]
comps = path.split('/')
i = 0
while i < len(comps):
if comps[i] == '.':
del comps[i]
elif comps[i] == '..' and i > 0 and comps[i-1] not in ('', '..'):
del comps[i-1:i+1]
i = i - 1
elif comps[i] == '' and i > 0 and comps[i-1] != '':
del comps[i]
else:
i = 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.
def abspath(path):
"""Return the absolute version of a path"""
if not isabs(path):
path = join(os.getcwd(), path)
return normpath(path)
# realpath is a no-op on systems without islink support
realpath = abspath
supports_unicode_filenames = False