440 lines
14 KiB
Python
440 lines
14 KiB
Python
|
"""Common operations on Posix pathnames.
|
||
|
|
|
||
|
|
Instead of importing this module directly, import os and refer to
|
||
|
|
this module as os.path. The "os.path" name is an alias for this
|
||
|
|
module on Posix systems; on other systems (e.g. Mac, Windows),
|
||
|
|
os.path provides the same operations in a manner specific to that
|
||
|
|
platform, and is an alias to another module (e.g. macpath, ntpath).
|
||
|
|
|
||
|
|
Some of this can actually be useful on non-Posix systems too, e.g.
|
||
|
|
for manipulation of the pathname component of URLs.
|
||
|
|
"""
|
||
|
|
|
||
|
|
import os
|
||
|
|
import sys
|
||
|
|
import stat
|
||
|
|
import genericpath
|
||
|
|
import warnings
|
||
|
|
from genericpath import *
|
||
|
|
from genericpath import _unicode
|
||
|
|
|
||
|
|
__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",
|
||
|
|
"samefile","sameopenfile","samestat",
|
||
|
|
"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 = ':'
|
||
|
|
defpath = ':/bin:/usr/bin'
|
||
|
|
altsep = None
|
||
|
|
devnull = '/dev/null'
|
||
|
|
|
||
|
|
# Normalize the case of a pathname. Trivial in Posix, string.lower on Mac.
|
||
|
|
# On MS-DOS this may also turn slashes into backslashes; however, other
|
||
|
|
# normalizations (such as optimizing '../' away) are not allowed
|
||
|
|
# (another function should be defined to do that).
|
||
|
|
|
||
|
|
def normcase(s):
|
||
|
|
"""Normalize case of pathname. Has no effect under Posix"""
|
||
|
|
return s
|
||
|
|
|
||
|
|
|
||
|
|
# Return whether a path is absolute.
|
||
|
|
# Trivial in Posix, harder on the Mac or MS-DOS.
|
||
|
|
|
||
|
|
def isabs(s):
|
||
|
|
"""Test whether a path is absolute"""
|
||
|
|
return s.startswith('/')
|
||
|
|
|
||
|
|
|
||
|
|
# Join pathnames.
|
||
|
|
# Ignore the previous parts if a part is absolute.
|
||
|
|
# Insert a '/' unless the first part is empty or already ends in '/'.
|
||
|
|
|
||
|
|
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. An empty last part will result in a path that
|
||
|
|
ends with a separator."""
|
||
|
|
path = a
|
||
|
|
for b in p:
|
||
|
|
if b.startswith('/'):
|
||
|
|
path = b
|
||
|
|
elif path == '' or path.endswith('/'):
|
||
|
|
path += b
|
||
|
|
else:
|
||
|
|
path += '/' + b
|
||
|
|
return path
|
||
|
|
|
||
|
|
|
||
|
|
# Split a path in head (everything up to the last '/') and tail (the
|
||
|
|
# rest). If the path ends in '/', tail will be empty. If there is no
|
||
|
|
# '/' in the path, head will be empty.
|
||
|
|
# Trailing '/'es are stripped from head unless it is the root.
|
||
|
|
|
||
|
|
def split(p):
|
||
|
|
"""Split a pathname. Returns tuple "(head, tail)" where "tail" is
|
||
|
|
everything after the final slash. Either part may be empty."""
|
||
|
|
i = p.rfind('/') + 1
|
||
|
|
head, tail = p[:i], p[i:]
|
||
|
|
if head and head != '/'*len(head):
|
||
|
|
head = head.rstrip('/')
|
||
|
|
return 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__
|
||
|
|
|
||
|
|
# Split a pathname into a drive specification and the rest of the
|
||
|
|
# path. Useful on DOS/Windows/NT; on Unix, the drive is always empty.
|
||
|
|
|
||
|
|
def splitdrive(p):
|
||
|
|
"""Split a pathname into drive and path. On Posix, drive is always
|
||
|
|
empty."""
|
||
|
|
return '', p
|
||
|
|
|
||
|
|
|
||
|
|
# Return the tail (basename) part of a path, same as split(path)[1].
|
||
|
|
|
||
|
|
def basename(p):
|
||
|
|
"""Returns the final component of a pathname"""
|
||
|
|
i = p.rfind('/') + 1
|
||
|
|
return p[i:]
|
||
|
|
|
||
|
|
|
||
|
|
# Return the head (dirname) part of a path, same as split(path)[0].
|
||
|
|
|
||
|
|
def dirname(p):
|
||
|
|
"""Returns the directory component of a pathname"""
|
||
|
|
i = p.rfind('/') + 1
|
||
|
|
head = p[:i]
|
||
|
|
if head and head != '/'*len(head):
|
||
|
|
head = head.rstrip('/')
|
||
|
|
return head
|
||
|
|
|
||
|
|
|
||
|
|
# Is a path a symbolic link?
|
||
|
|
# This will always return false on systems where os.lstat doesn't exist.
|
||
|
|
|
||
|
|
def islink(path):
|
||
|
|
"""Test whether a path is a symbolic link"""
|
||
|
|
try:
|
||
|
|
st = os.lstat(path)
|
||
|
|
except (os.error, AttributeError):
|
||
|
|
return False
|
||
|
|
return stat.S_ISLNK(st.st_mode)
|
||
|
|
|
||
|
|
# Being true for dangling symbolic links is also useful.
|
||
|
|
|
||
|
|
def lexists(path):
|
||
|
|
"""Test whether a path exists. Returns True for broken symbolic links"""
|
||
|
|
try:
|
||
|
|
os.lstat(path)
|
||
|
|
except os.error:
|
||
|
|
return False
|
||
|
|
return True
|
||
|
|
|
||
|
|
|
||
|
|
# Are two filenames really pointing to the same file?
|
||
|
|
|
||
|
|
def samefile(f1, f2):
|
||
|
|
"""Test whether two pathnames reference the same actual file"""
|
||
|
|
s1 = os.stat(f1)
|
||
|
|
s2 = os.stat(f2)
|
||
|
|
return samestat(s1, s2)
|
||
|
|
|
||
|
|
|
||
|
|
# Are two open files really referencing the same file?
|
||
|
|
# (Not necessarily the same file descriptor!)
|
||
|
|
|
||
|
|
def sameopenfile(fp1, fp2):
|
||
|
|
"""Test whether two open file objects reference the same file"""
|
||
|
|
s1 = os.fstat(fp1)
|
||
|
|
s2 = os.fstat(fp2)
|
||
|
|
return samestat(s1, s2)
|
||
|
|
|
||
|
|
|
||
|
|
# Are two stat buffers (obtained from stat, fstat or lstat)
|
||
|
|
# describing the same file?
|
||
|
|
|
||
|
|
def samestat(s1, s2):
|
||
|
|
"""Test whether two stat buffers reference the same file"""
|
||
|
|
return s1.st_ino == s2.st_ino and \
|
||
|
|
s1.st_dev == s2.st_dev
|
||
|
|
|
||
|
|
|
||
|
|
# Is a path a mount point?
|
||
|
|
# (Does this work for all UNIXes? Is it even guaranteed to work by Posix?)
|
||
|
|
|
||
|
|
def ismount(path):
|
||
|
|
"""Test whether a path is a mount point"""
|
||
|
|
if islink(path):
|
||
|
|
# A symlink can never be a mount point
|
||
|
|
return False
|
||
|
|
try:
|
||
|
|
s1 = os.lstat(path)
|
||
|
|
s2 = os.lstat(join(path, '..'))
|
||
|
|
except os.error:
|
||
|
|
return False # It doesn't exist -- so not a mount point :-)
|
||
|
|
dev1 = s1.st_dev
|
||
|
|
dev2 = s2.st_dev
|
||
|
|
if dev1 != dev2:
|
||
|
|
return True # path/.. on a different device as path
|
||
|
|
ino1 = s1.st_ino
|
||
|
|
ino2 = s2.st_ino
|
||
|
|
if ino1 == ino2:
|
||
|
|
return True # path/.. is the same i-node as path
|
||
|
|
return False
|
||
|
|
|
||
|
|
|
||
|
|
# 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 with callback function.
|
||
|
|
|
||
|
|
For each directory in the directory tree rooted at top (including top
|
||
|
|
itself, but excluding '.' and '..'), call func(arg, dirname, fnames).
|
||
|
|
dirname is the name of the directory, and fnames a list of the names of
|
||
|
|
the files and subdirectories in dirname (excluding '.' and '..'). func
|
||
|
|
may modify the fnames list in-place (e.g. via del or slice assignment),
|
||
|
|
and walk will only recurse into the subdirectories whose names remain in
|
||
|
|
fnames; this can be used to implement a filter, or to impose a specific
|
||
|
|
order of visiting. No semantics are defined for, or required of, arg,
|
||
|
|
beyond that arg is always passed to func. It can be used, e.g., to pass
|
||
|
|
a filename pattern, or a mutable object designed to accumulate
|
||
|
|
statistics. Passing None for arg is common."""
|
||
|
|
warnings.warnpy3k("In 3.x, os.path.walk is removed in favor of os.walk.",
|
||
|
|
stacklevel=2)
|
||
|
|
try:
|
||
|
|
names = os.listdir(top)
|
||
|
|
except os.error:
|
||
|
|
return
|
||
|
|
func(arg, top, names)
|
||
|
|
for name in names:
|
||
|
|
name = join(top, name)
|
||
|
|
try:
|
||
|
|
st = os.lstat(name)
|
||
|
|
except os.error:
|
||
|
|
continue
|
||
|
|
if stat.S_ISDIR(st.st_mode):
|
||
|
|
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 constructions. If user or $HOME is unknown,
|
||
|
|
do nothing."""
|
||
|
|
if not path.startswith('~'):
|
||
|
|
return path
|
||
|
|
i = path.find('/', 1)
|
||
|
|
if i < 0:
|
||
|
|
i = len(path)
|
||
|
|
if i == 1:
|
||
|
|
if 'HOME' not in os.environ:
|
||
|
|
import pwd
|
||
|
|
userhome = pwd.getpwuid(os.getuid()).pw_dir
|
||
|
|
else:
|
||
|
|
userhome = os.environ['HOME']
|
||
|
|
else:
|
||
|
|
import pwd
|
||
|
|
try:
|
||
|
|
pwent = pwd.getpwnam(path[1:i])
|
||
|
|
except KeyError:
|
||
|
|
return path
|
||
|
|
userhome = pwent.pw_dir
|
||
|
|
userhome = userhome.rstrip('/')
|
||
|
|
return (userhome + path[i:]) or '/'
|
||
|
|
|
||
|
|
|
||
|
|
# Expand paths containing shell variable substitutions.
|
||
|
|
# This expands the forms $variable and ${variable} only.
|
||
|
|
# Non-existent variables are left unchanged.
|
||
|
|
|
||
|
|
_varprog = None
|
||
|
|
_uvarprog = None
|
||
|
|
|
||
|
|
def expandvars(path):
|
||
|
|
"""Expand shell variables of form $var and ${var}. Unknown variables
|
||
|
|
are left unchanged."""
|
||
|
|
global _varprog, _uvarprog
|
||
|
|
if '$' not in path:
|
||
|
|
return path
|
||
|
|
if isinstance(path, _unicode):
|
||
|
|
if not _uvarprog:
|
||
|
|
import re
|
||
|
|
_uvarprog = re.compile(ur'\$(\w+|\{[^}]*\})', re.UNICODE)
|
||
|
|
varprog = _uvarprog
|
||
|
|
encoding = sys.getfilesystemencoding()
|
||
|
|
else:
|
||
|
|
if not _varprog:
|
||
|
|
import re
|
||
|
|
_varprog = re.compile(r'\$(\w+|\{[^}]*\})')
|
||
|
|
varprog = _varprog
|
||
|
|
encoding = None
|
||
|
|
i = 0
|
||
|
|
while True:
|
||
|
|
m = varprog.search(path, i)
|
||
|
|
if not m:
|
||
|
|
break
|
||
|
|
i, j = m.span(0)
|
||
|
|
name = m.group(1)
|
||
|
|
if name.startswith('{') and name.endswith('}'):
|
||
|
|
name = name[1:-1]
|
||
|
|
if encoding:
|
||
|
|
name = name.encode(encoding)
|
||
|
|
if name in os.environ:
|
||
|
|
tail = path[j:]
|
||
|
|
value = os.environ[name]
|
||
|
|
if encoding:
|
||
|
|
value = value.decode(encoding)
|
||
|
|
path = path[:i] + value
|
||
|
|
i = len(path)
|
||
|
|
path += tail
|
||
|
|
else:
|
||
|
|
i = j
|
||
|
|
return path
|
||
|
|
|
||
|
|
|
||
|
|
# Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B.
|
||
|
|
# It should be understood that this may change the meaning of the path
|
||
|
|
# if it contains symbolic links!
|
||
|
|
|
||
|
|
def normpath(path):
|
||
|
|
"""Normalize path, eliminating double slashes, etc."""
|
||
|
|
# Preserve unicode (if path is unicode)
|
||
|
|
slash, dot = (u'/', u'.') if isinstance(path, _unicode) else ('/', '.')
|
||
|
|
if path == '':
|
||
|
|
return dot
|
||
|
|
initial_slashes = path.startswith('/')
|
||
|
|
# POSIX allows one or two initial slashes, but treats three or more
|
||
|
|
# as single slash.
|
||
|
|
if (initial_slashes and
|
||
|
|
path.startswith('//') and not path.startswith('///')):
|
||
|
|
initial_slashes = 2
|
||
|
|
comps = path.split('/')
|
||
|
|
new_comps = []
|
||
|
|
for comp in comps:
|
||
|
|
if comp in ('', '.'):
|
||
|
|
continue
|
||
|
|
if (comp != '..' or (not initial_slashes and not new_comps) or
|
||
|
|
(new_comps and new_comps[-1] == '..')):
|
||
|
|
new_comps.append(comp)
|
||
|
|
elif new_comps:
|
||
|
|
new_comps.pop()
|
||
|
|
comps = new_comps
|
||
|
|
path = slash.join(comps)
|
||
|
|
if initial_slashes:
|
||
|
|
path = slash*initial_slashes + path
|
||
|
|
return path or dot
|
||
|
|
|
||
|
|
|
||
|
|
def abspath(path):
|
||
|
|
"""Return an absolute path."""
|
||
|
|
if not isabs(path):
|
||
|
|
if isinstance(path, _unicode):
|
||
|
|
cwd = os.getcwdu()
|
||
|
|
else:
|
||
|
|
cwd = os.getcwd()
|
||
|
|
path = join(cwd, path)
|
||
|
|
return normpath(path)
|
||
|
|
|
||
|
|
|
||
|
|
# Return a canonical path (i.e. the absolute location of a file on the
|
||
|
|
# filesystem).
|
||
|
|
|
||
|
|
def realpath(filename):
|
||
|
|
"""Return the canonical path of the specified filename, eliminating any
|
||
|
|
symbolic links encountered in the path."""
|
||
|
|
path, ok = _joinrealpath('', filename, {})
|
||
|
|
return abspath(path)
|
||
|
|
|
||
|
|
# Join two paths, normalizing ang eliminating any symbolic links
|
||
|
|
# encountered in the second path.
|
||
|
|
def _joinrealpath(path, rest, seen):
|
||
|
|
if isabs(rest):
|
||
|
|
rest = rest[1:]
|
||
|
|
path = sep
|
||
|
|
|
||
|
|
while rest:
|
||
|
|
name, _, rest = rest.partition(sep)
|
||
|
|
if not name or name == curdir:
|
||
|
|
# current dir
|
||
|
|
continue
|
||
|
|
if name == pardir:
|
||
|
|
# parent dir
|
||
|
|
if path:
|
||
|
|
path, name = split(path)
|
||
|
|
if name == pardir:
|
||
|
|
path = join(path, pardir, pardir)
|
||
|
|
else:
|
||
|
|
path = pardir
|
||
|
|
continue
|
||
|
|
newpath = join(path, name)
|
||
|
|
if not islink(newpath):
|
||
|
|
path = newpath
|
||
|
|
continue
|
||
|
|
# Resolve the symbolic link
|
||
|
|
if newpath in seen:
|
||
|
|
# Already seen this path
|
||
|
|
path = seen[newpath]
|
||
|
|
if path is not None:
|
||
|
|
# use cached value
|
||
|
|
continue
|
||
|
|
# The symlink is not resolved, so we must have a symlink loop.
|
||
|
|
# Return already resolved part + rest of the path unchanged.
|
||
|
|
return join(newpath, rest), False
|
||
|
|
seen[newpath] = None # not resolved symlink
|
||
|
|
path, ok = _joinrealpath(path, os.readlink(newpath), seen)
|
||
|
|
if not ok:
|
||
|
|
return join(path, rest), False
|
||
|
|
seen[newpath] = path # resolved symlink
|
||
|
|
|
||
|
|
return path, True
|
||
|
|
|
||
|
|
|
||
|
|
supports_unicode_filenames = (sys.platform == 'darwin')
|
||
|
|
|
||
|
|
def relpath(path, start=curdir):
|
||
|
|
"""Return a relative version of a path"""
|
||
|
|
|
||
|
|
if not path:
|
||
|
|
raise ValueError("no path specified")
|
||
|
|
|
||
|
|
start_list = [x for x in abspath(start).split(sep) if x]
|
||
|
|
path_list = [x for x in abspath(path).split(sep) if x]
|
||
|
|
|
||
|
|
# Work out how much of the filepath is shared by start and path.
|
||
|
|
i = len(commonprefix([start_list, path_list]))
|
||
|
|
|
||
|
|
rel_list = [pardir] * (len(start_list)-i) + path_list[i:]
|
||
|
|
if not rel_list:
|
||
|
|
return curdir
|
||
|
|
return join(*rel_list)
|