cpython/Lib/macpath.py
1996-07-23 02:28:32 +00:00

192 lines
4.4 KiB
Python

# module 'macpath' -- pathname (or -related) operations for the Macintosh
import string
import mac
from stat import *
# Normalize the case of a pathname. Dummy in Posix, but string.lower here.
normcase = string.lower
# Return true if a path is absolute.
# On the Mac, relative paths begin with a colon,
# but as a special case, paths with no colons at all are also relative.
# Anything else is absolute (the string up to the first colon is the
# volume name).
def isabs(s):
return ':' in s and s[0] <> ':'
# Join two pathnames.
# The result is equivalent to what the second pathname would refer to
# if the first pathname were the current directory.
def join(s, t):
if (not s) or isabs(t): return t
if t[:1] == ':': t = t[1:]
if ':' not in s:
s = ':' + s
if s[-1:] <> ':':
s = s + ':'
return s + t
# Split a pathname in two parts: the directory leading up to the final bit,
# and the basename (the filename, without colons, in that directory).
# The result (s, t) is such that join(s, t) yields the original argument.
def split(s):
if ':' not in s: return '', s
colon = 0
for i in range(len(s)):
if s[i] == ':': colon = i+1
return s[:colon-1], s[colon:]
# 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):
root, ext = '', ''
for c in p:
if c == ':':
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
# Split a pathname into a drive specification and the rest of the
# path. Useful on DOS/Windows/NT; on the Mac, the drive is always
# empty (don't use the volume name -- it doesn't have the same
# syntactic and semantic oddities as DOS drive letters, such as there
# being a separate current directory per drive).
def splitdrive(p):
return '', p
# Short interfaces to split()
def dirname(s): return split(s)[0]
def basename(s): return split(s)[1]
# Return true if the pathname refers to an existing directory.
def isdir(s):
try:
st = mac.stat(s)
except mac.error:
return 0
return S_ISDIR(st[ST_MODE])
# Return true if the pathname refers to a symbolic link.
# (Always false on the Mac, until we understand Aliases.)
def islink(s):
return 0
# Return true if the pathname refers to an existing regular file.
def isfile(s):
try:
st = mac.stat(s)
except mac.error:
return 0
return S_ISREG(st[ST_MODE])
# Return true if the pathname refers to an existing file or directory.
def exists(s):
try:
st = mac.stat(s)
except mac.error:
return 0
return 1
#
# dummy expandvars to retain interface-compatability with other
# operating systems.
def expandvars(path):
return path
#
# dummy expanduser to retain interface-compatability with other
# operating systems.
def expanduser(path):
return path
# Normalize a pathname: get rid of '::' sequences by backing up,
# e.g., 'foo:bar::bletch' becomes 'foo:bletch'.
# Raise the exception norm_error below if backing up is impossible,
# e.g., for '::foo'.
# XXX The Unix version doesn't raise an exception but simply
# returns an unnormalized path. Should do so here too.
norm_error = 'macpath.norm_error: path cannot be normalized'
def normpath(s):
import string
if ':' not in s:
return ':' + s
f = string.splitfields(s, ':')
pre = []
post = []
if not f[0]:
pre = f[:1]
f = f[1:]
if not f[len(f)-1]:
post = f[-1:]
f = f[:-1]
res = []
for seg in f:
if seg:
res.append(seg)
else:
if not res: raise norm_error, 'path starts with ::'
del res[len(res)-1]
if not (pre or res):
raise norm_error, 'path starts with volume::'
if pre: res = pre + res
if post: res = res + post
s = res[0]
for seg in res[1:]:
s = s + ':' + seg
return s
# 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.
# 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 = mac.listdir(top)
except mac.error:
return
func(arg, top, names)
for name in names:
name = join(top, name)
if isdir(name):
walk(name, func, arg)