Make nicer comments.
Added expanduser() and normcase() and isabs() and isfile().
diff --git a/Lib/posixpath.py b/Lib/posixpath.py
index fa72ecb..f244ca5 100644
--- a/Lib/posixpath.py
+++ b/Lib/posixpath.py
@@ -4,11 +4,26 @@
import stat
+# 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):
+ return s
+
+
+# Return wheter a path is absolute.
+# Trivial in Posix, harder on the Mac or MS-DOS.
+
+def isabs(s):
+ return s[:1] == '/'
+
+
# Join two pathnames.
+# Ignore the first part if the second part is absolute.
# Insert a '/' unless the first part is empty or already ends in '/'.
-# Ignore the first part altogether if the second part is absolute
-# (begins with '/').
-#
+
def join(a, b):
if b[:1] == '/': return b
if a == '' or a[-1:] == '/': return a + b
@@ -16,13 +31,14 @@
return a + '/' + b
-cat = join # For compatibility
-
-
# Split a path in head (empty or ending in '/') and tail (no '/').
# The tail will be empty if the path ends in '/'.
-# It is always true that head+tail = p.
-#
+# It is always true that head + tail == p; also join(head, tail) == p.
+# Note that because head ends in '/', if you want to find all components
+# of a path by repeatedly getting the head, you will have to strip off
+# the trailing '/' yourself (another function should be defined to
+# split an entire path into components.)
+
def split(p):
head, tail = '', ''
for c in p:
@@ -35,8 +51,8 @@
# Split a path in root and extension.
# The extension is everything starting at the first dot in the last
# pathname component; the root is everything before that.
-# It is always true that root+ext = p.
-#
+# It is always true that root + ext == p.
+
def splitext(p):
root, ext = '', ''
for c in p:
@@ -50,13 +66,13 @@
# Return the tail (basename) part of a path.
-#
+
def basename(p):
return split(p)[1]
# Return the longest prefix of all list elements.
-#
+
def commonprefix(m):
if not m: return ''
prefix = m[0]
@@ -69,8 +85,20 @@
return prefix
-# Does a file/directory exist?
-#
+# Is a path a symbolic link?
+# This will always return false on systems where posix.lstat doesn't exist.
+
+def islink(path):
+ try:
+ st = posix.lstat(path)
+ except (posix.error, AttributeError):
+ return 0
+ return stat.S_ISLNK(st[stat.ST_MODE])
+
+
+# Does a path exist?
+# This is false for dangling symbolic links.
+
def exists(path):
try:
st = posix.stat(path)
@@ -80,7 +108,9 @@
# Is a path a posix directory?
-#
+# This follows symbolic links, so both islink() and isdir() can be true
+# for the same path.
+
def isdir(path):
try:
st = posix.stat(path)
@@ -89,19 +119,20 @@
return stat.S_ISDIR(st[stat.ST_MODE])
-# Is a path a symbolic link?
-# This will always return false on systems where posix.lstat doesn't exist.
-#
-def islink(path):
+# Is a path a regulat file?
+# This follows symbolic links, so both islink() and isdir() can be true
+# for the same path.
+
+def isfile(path):
try:
- st = posix.lstat(path)
- except (posix.error, AttributeError):
+ st = posix.stat(path)
+ except posix.error:
return 0
- return stat.S_ISLNK(st[stat.ST_MODE])
+ return stat.S_ISREG(st[stat.ST_MODE])
# Are two filenames really pointing to the same file?
-#
+
def samefile(f1, f2):
s1 = posix.stat(f1)
s2 = posix.stat(f2)
@@ -111,7 +142,7 @@
# Are two open files really referencing the same file?
# (Not necessarily the same file descriptor!)
# XXX Oops, posix.fstat() doesn't exist yet!
-#
+
def sameopenfile(fp1, fp2):
s1 = posix.fstat(fp1)
s2 = posix.fstat(fp2)
@@ -120,7 +151,7 @@
# Are two stat buffers (obtained from stat, fstat or lstat)
# describing the same file?
-#
+
def samestat(s1, s2):
return s1[stat.ST_INO] == s2[stat.ST_INO] and \
s1[stat.ST_DEV] == s2[stat.STD_DEV]
@@ -143,24 +174,28 @@
# Is a path a mount point?
-# This only works for normalized, absolute paths,
+# This only works for normalized paths,
# and only if the mount table as printed by /etc/mount is correct.
-# Sorry.
-#
+# It tries to make relative paths absolute by prefixing them with the
+# current directory, but it won't normalize arguments containing '../'
+# or symbolic links.
+
def ismount(path):
+ if not isabs(path):
+ path = join(posix.getcwd(), path)
if not _mounts:
_mounts[:] = _getmounts()
return path in _mounts
# Directory tree walk.
-# For each directory under top (including top itself),
-# 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.
-# func may modify the filenames list, to implement a filter,
+# 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
+# files 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):
try:
names = posix.listdir(top)
@@ -173,3 +208,32 @@
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):
+ if path[:1] <> '~':
+ return path
+ i, n = 1, len(path)
+ while i < n and path[i] <> '/':
+ i = i+1
+ if i == 1:
+ if not posix.environ.has_key('HOME'):
+ return path
+ userhome = posix.environ['HOME']
+ else:
+ import pwd
+ try:
+ pwent = pwd.getpwnam(path[1:i])
+ except KeyError:
+ return path
+ userhome = pwent[5]
+ return userhome + path[i:]