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Python-1.4
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amigapath.py
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1998-06-24
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# Module 'amigapath' -- common operations on AMIGA pathnames
# Irmen de Jong, april 1st, 1996 (no joke)
# (adapted from `posixpath.py')
#
# 26-mar-96: fixed split, islink. Improved expanduser.
# 1-apr-96: fixed expanduser (works 100% now)
# 25-dec-96: slight changes to comments and expanduser.
#
import amiga
import stat
import string
# normalize the case of a pathname
normcase = string.lower
# Return wheter a path is absolute. On Amiga: when a ':' occurs in it.
def isabs(s):
return ':' in s
# 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 '/' or ':'.
def join(a, b):
if ':' in b: return b
if a == '' or a[-1:] == '/': return a + b
# Note: join('x', '') returns 'x/'; is this what we want?
if a[-1:]==':': return a+b
return a + '/' + b
# Split a path in head (everything up to the last '/' or ':') and tail (the
# rest). If the path ends in '/' or ':', tail will be empty. If there is no
# '/' or ':' in the path, head will be empty.
# DIFFERENCE WITH posixpath: only ONE trailing '/' will be stripped from head!
# (on the Amiga a double slash means "parent dir"! ) This means that if
# head ends in a '/', you MUST add a '/' to it when reconstructing the path,
# or you will lose the "parent dir" slash.
# Functions that depend on this function are also affected!
# (basename, dirname)
#
# Suggested by Kent Polk, kent@eaenki.nde.swri.edu
def split(p):
i = string.rfind(p, '/')
j = string.rfind(p, ':')
if (i>j) and p[-1]=='/':
p=p[:-1]
i = string.rfind(p, '/')
if (j>i) or ((j>=0) and (i<0)): i=j
head, tail = p[:i+1], p[i+1:]
if head:
if head[-1]=='/': head=head[:-1]
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):
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/Amiga; on Unix, the drive is always empty.
def splitdrive(p):
i = string.rfind(p,':') + 1
if i<=0: return '', p
return p[:i],p[i:]
# Return the tail (basename) part of a path.
def basename(p):
return split(p)[1]
# Return the head (dirname) part of a path.
def dirname(p):
return split(p)[0]
# Get the full pathname of a file/directory (i.e. expand assigns).
fullpath = amiga.fullpath
# Return the longest prefix of all list elements.
def commonprefix(m):
if not m: return ''
prefix = m[0]
for item in m:
for i in range(len(prefix)):
if prefix[:i+1] <> item[:i+1]:
prefix = prefix[:i]
if i == 0: return ''
break
return prefix
# Is a path a symbolic link?
# This will always return false on systems where amiga.lstat doesn't exist.
# (or where S_ISLNK isn't defined)
def islink(path):
try:
st = amiga.lstat(path)
return stat.S_ISLNK(st[stat.ST_MODE])
except (amiga.error, AttributeError):
return 0
# Does a path exist?
# This is false for dangling symbolic links.
def exists(path):
try:
st = amiga.stat(path)
except amiga.error:
return 0
return 1
# Is a path an amiga directory?
# This follows symbolic links, so both islink() and isdir() can be true
# for the same path.
def isdir(path):
try:
st = amiga.stat(path)
except amiga.error:
return 0
return stat.S_ISDIR(st[stat.ST_MODE])
# Is a path a regular file?
# This follows symbolic links, so both islink() and isfile() can be true
# for the same path.
def isfile(path):
try:
st = amiga.stat(path)
except amiga.error:
return 0
return stat.S_ISREG(st[stat.ST_MODE])
# Are two filenames really pointing to the same file?
def samefile(f1, f2):
s1 = amiga.stat(f1)
s2 = amiga.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):
s1 = amiga.fstat(fp1)
s2 = amiga.fstat(fp2)
return samestat(s1, s2)
# 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.ST_DEV]
# Is a path a mount point? AMIGA: Is it a device name?
def ismount(path):
drive,rest = splitdrive(path)
if rest=='':
return 1
else:
return 0
# 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
# 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 = amiga.listdir(top)
except amiga.error:
return
func(arg, top, names)
for name in names:
name = join(top, name)
if isdir(name) and not islink(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 amiga.environ.has_key('HOME'):
return path
userhome = amiga.environ['HOME']
else:
try:
import pwd
pwent = pwd.getpwnam(path[1:i])
except (KeyError,ImportError,SystemError):
return path # ~user only works if pwd module works
userhome = pwent[5]
if userhome[-1:] == '/': i = i+1
return userhome + path[i:]
# Expand paths containing shell variable substitutions.
# This expands the forms $variable and ${variable} only.
# Non-existant variables are left unchanged.
_varprog = None
def expandvars(path):
global _varprog
if '$' not in path:
return path
if not _varprog:
import regex
_varprog = regex.compile('$\([a-zA-Z0-9_]+\|{[^}]*}\)')
i = 0
while 1:
i = _varprog.search(path, i)
if i < 0:
break
name = _varprog.group(1)
j = i + len(_varprog.group(0))
if name[:1] == '{' and name[-1:] == '}':
name = name[1:-1]
if amiga.environ.has_key(name):
tail = path[j:]
path = path[:i] + amiga.environ[name]
i = len(path)
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!
# Note: does nothing on Amiga because x/y//z is different than x/y/z.
def normpath(path):
return path