/usr/lib/python2.6/posixpath.py is in python2.6-minimal 2.6.8-1.1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 | """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 stat
import genericpath
import warnings
from genericpath import *
__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."""
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:
st = 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('/') or userhome
return userhome + path[i:]
# Expand paths containing shell variable substitutions.
# This expands the forms $variable and ${variable} only.
# Non-existent variables are left unchanged.
_varprog = None
def expandvars(path):
"""Expand shell variables of form $var and ${var}. Unknown variables
are left unchanged."""
global _varprog
if '$' not in path:
return path
if not _varprog:
import re
_varprog = re.compile(r'\$(\w+|\{[^}]*\})')
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 name in os.environ:
tail = path[j:]
path = path[:i] + os.environ[name]
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."""
if isabs(filename):
bits = ['/'] + filename.split('/')[1:]
else:
bits = [''] + filename.split('/')
for i in range(2, len(bits)+1):
component = join(*bits[0:i])
# Resolve symbolic links.
if islink(component):
resolved = _resolve_link(component)
if resolved is None:
# Infinite loop -- return original component + rest of the path
return abspath(join(*([component] + bits[i:])))
else:
newpath = join(*([resolved] + bits[i:]))
return realpath(newpath)
return abspath(filename)
def _resolve_link(path):
"""Internal helper function. Takes a path and follows symlinks
until we either arrive at something that isn't a symlink, or
encounter a path we've seen before (meaning that there's a loop).
"""
paths_seen = []
while islink(path):
if path in paths_seen:
# Already seen this path, so we must have a symlink loop
return None
paths_seen.append(path)
# Resolve where the link points to
resolved = os.readlink(path)
if not isabs(resolved):
dir = dirname(path)
path = normpath(join(dir, resolved))
else:
path = normpath(resolved)
return path
supports_unicode_filenames = False
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)
# 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)
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