os2emxpath.py revision 117910dc445a2262bd96bbfefaf43714ae59c11b 
1# Module 'os2emxpath' -- common operations on OS/2 pathnames
2"""Common pathname manipulations, OS/2 EMX version.
3
4Instead of importing this module directly, import os and refer to this
5module as os.path.
6"""
7
8import os
9import stat
10
11__all__ = ["normcase","isabs","join","splitdrive","split","splitext",
12           "basename","dirname","commonprefix","getsize","getmtime",
13           "getatime","getctime", "islink","exists","isdir","isfile","ismount",
14           "walk","expanduser","expandvars","normpath","abspath","splitunc",
15           "curdir","pardir","sep","pathsep","defpath","altsep","extsep",
16           "realpath","supports_unicode_filenames"]
17
18# strings representing various path-related bits and pieces
19curdir = '.'
20pardir = '..'
21extsep = '.'
22sep = '/'
23altsep = '\\'
24pathsep = ';'
25defpath = '.;C:\\bin'
26
27# Normalize the case of a pathname and map slashes to backslashes.
28# Other normalizations (such as optimizing '../' away) are not done
29# (this is done by normpath).
30
31def normcase(s):
32    """Normalize case of pathname.
33
34    Makes all characters lowercase and all altseps into seps."""
35    return s.replace('\\', '/').lower()
36
37
38# Return whether a path is absolute.
39# Trivial in Posix, harder on the Mac or MS-DOS.
40# For DOS it is absolute if it starts with a slash or backslash (current
41# volume), or if a pathname after the volume letter and colon / UNC resource
42# starts with a slash or backslash.
43
44def isabs(s):
45    """Test whether a path is absolute"""
46    s = splitdrive(s)[1]
47    return s != '' and s[:1] in '/\\'
48
49
50# Join two (or more) paths.
51
52def join(a, *p):
53    """Join two or more pathname components, inserting sep as needed"""
54    path = a
55    for b in p:
56        if isabs(b):
57            path = b
58        elif path == '' or path[-1:] in '/\\:':
59            path = path + b
60        else:
61            path = path + '/' + b
62    return path
63
64
65# Split a path in a drive specification (a drive letter followed by a
66# colon) and the path specification.
67# It is always true that drivespec + pathspec == p
68def splitdrive(p):
69    """Split a pathname into drive and path specifiers. Returns a 2-tuple
70"(drive,path)";  either part may be empty"""
71    if p[1:2] == ':':
72        return p[0:2], p[2:]
73    return '', p
74
75
76# Parse UNC paths
77def splitunc(p):
78    """Split a pathname into UNC mount point and relative path specifiers.
79
80    Return a 2-tuple (unc, rest); either part may be empty.
81    If unc is not empty, it has the form '//host/mount' (or similar
82    using backslashes).  unc+rest is always the input path.
83    Paths containing drive letters never have an UNC part.
84    """
85    if p[1:2] == ':':
86        return '', p # Drive letter present
87    firstTwo = p[0:2]
88    if firstTwo == '/' * 2 or firstTwo == '\\' * 2:
89        # is a UNC path:
90        # vvvvvvvvvvvvvvvvvvvv equivalent to drive letter
91        # \\machine\mountpoint\directories...
92        #           directory ^^^^^^^^^^^^^^^
93        normp = normcase(p)
94        index = normp.find('/', 2)
95        if index == -1:
96            ##raise RuntimeError, 'illegal UNC path: "' + p + '"'
97            return ("", p)
98        index = normp.find('/', index + 1)
99        if index == -1:
100            index = len(p)
101        return p[:index], p[index:]
102    return '', p
103
104
105# Split a path in head (everything up to the last '/') and tail (the
106# rest).  After the trailing '/' is stripped, the invariant
107# join(head, tail) == p holds.
108# The resulting head won't end in '/' unless it is the root.
109
110def split(p):
111    """Split a pathname.
112
113    Return tuple (head, tail) where tail is everything after the final slash.
114    Either part may be empty."""
115
116    d, p = splitdrive(p)
117    # set i to index beyond p's last slash
118    i = len(p)
119    while i and p[i-1] not in '/\\':
120        i = i - 1
121    head, tail = p[:i], p[i:]  # now tail has no slashes
122    # remove trailing slashes from head, unless it's all slashes
123    head2 = head
124    while head2 and head2[-1] in '/\\':
125        head2 = head2[:-1]
126    head = head2 or head
127    return d + head, tail
128
129
130# Split a path in root and extension.
131# The extension is everything starting at the last dot in the last
132# pathname component; the root is everything before that.
133# It is always true that root + ext == p.
134
135def splitext(p):
136    """Split the extension from a pathname.
137
138    Extension is everything from the last dot to the end.
139    Return (root, ext), either part may be empty."""
140    root, ext = '', ''
141    for c in p:
142        if c in ['/','\\']:
143            root, ext = root + ext + c, ''
144        elif c == '.':
145            if ext:
146                root, ext = root + ext, c
147            else:
148                ext = c
149        elif ext:
150            ext = ext + c
151        else:
152            root = root + c
153    return root, ext
154
155
156# Return the tail (basename) part of a path.
157
158def basename(p):
159    """Returns the final component of a pathname"""
160    return split(p)[1]
161
162
163# Return the head (dirname) part of a path.
164
165def dirname(p):
166    """Returns the directory component of a pathname"""
167    return split(p)[0]
168
169
170# Return the longest prefix of all list elements.
171
172def commonprefix(m):
173    "Given a list of pathnames, returns the longest common leading component"
174    if not m: return ''
175    prefix = m[0]
176    for item in m:
177        for i in range(len(prefix)):
178            if prefix[:i+1] != item[:i+1]:
179                prefix = prefix[:i]
180                if i == 0: return ''
181                break
182    return prefix
183
184
185# Get size, mtime, atime of files.
186
187def getsize(filename):
188    """Return the size of a file, reported by os.stat()"""
189    return os.stat(filename).st_size
190
191def getmtime(filename):
192    """Return the last modification time of a file, reported by os.stat()"""
193    return os.stat(filename).st_mtime
194
195def getatime(filename):
196    """Return the last access time of a file, reported by os.stat()"""
197    return os.stat(filename).st_atime
198
199def getctime(filename):
200    """Return the creation time of a file, reported by os.stat()."""
201    return os.stat(filename).st_ctime
202
203# Is a path a symbolic link?
204# This will always return false on systems where posix.lstat doesn't exist.
205
206def islink(path):
207    """Test for symbolic link.  On OS/2 always returns false"""
208    return False
209
210
211# Does a path exist?
212# This is false for dangling symbolic links.
213
214def exists(path):
215    """Test whether a path exists"""
216    try:
217        st = os.stat(path)
218    except os.error:
219        return False
220    return True
221
222
223# Is a path a directory?
224
225def isdir(path):
226    """Test whether a path is a directory"""
227    try:
228        st = os.stat(path)
229    except os.error:
230        return False
231    return stat.S_ISDIR(st.st_mode)
232
233
234# Is a path a regular file?
235# This follows symbolic links, so both islink() and isdir() can be true
236# for the same path.
237
238def isfile(path):
239    """Test whether a path is a regular file"""
240    try:
241        st = os.stat(path)
242    except os.error:
243        return False
244    return stat.S_ISREG(st.st_mode)
245
246
247# Is a path a mount point?  Either a root (with or without drive letter)
248# or an UNC path with at most a / or \ after the mount point.
249
250def ismount(path):
251    """Test whether a path is a mount point (defined as root of drive)"""
252    unc, rest = splitunc(path)
253    if unc:
254        return rest in ("", "/", "\\")
255    p = splitdrive(path)[1]
256    return len(p) == 1 and p[0] in '/\\'
257
258
259# Directory tree walk.
260# For each directory under top (including top itself, but excluding
261# '.' and '..'), func(arg, dirname, filenames) is called, where
262# dirname is the name of the directory and filenames is the list
263# files files (and subdirectories etc.) in the directory.
264# The func may modify the filenames list, to implement a filter,
265# or to impose a different order of visiting.
266
267def walk(top, func, arg):
268    """Directory tree walk whth callback function.
269
270    walk(top, func, arg) calls func(arg, d, files) for each directory d
271    in the tree rooted at top (including top itself); files is a list
272    of all the files and subdirs in directory d."""
273    try:
274        names = os.listdir(top)
275    except os.error:
276        return
277    func(arg, top, names)
278    exceptions = ('.', '..')
279    for name in names:
280        if name not in exceptions:
281            name = join(top, name)
282            if isdir(name):
283                walk(name, func, arg)
284
285
286# Expand paths beginning with '~' or '~user'.
287# '~' means $HOME; '~user' means that user's home directory.
288# If the path doesn't begin with '~', or if the user or $HOME is unknown,
289# the path is returned unchanged (leaving error reporting to whatever
290# function is called with the expanded path as argument).
291# See also module 'glob' for expansion of *, ? and [...] in pathnames.
292# (A function should also be defined to do full *sh-style environment
293# variable expansion.)
294
295def expanduser(path):
296    """Expand ~ and ~user constructs.
297
298    If user or $HOME is unknown, do nothing."""
299    if path[:1] != '~':
300        return path
301    i, n = 1, len(path)
302    while i < n and path[i] not in '/\\':
303        i = i + 1
304    if i == 1:
305        if 'HOME' in os.environ:
306            userhome = os.environ['HOME']
307        elif not 'HOMEPATH' in os.environ:
308            return path
309        else:
310            try:
311                drive = os.environ['HOMEDRIVE']
312            except KeyError:
313                drive = ''
314            userhome = join(drive, os.environ['HOMEPATH'])
315    else:
316        return path
317    return userhome + path[i:]
318
319
320# Expand paths containing shell variable substitutions.
321# The following rules apply:
322#       - no expansion within single quotes
323#       - no escape character, except for '$$' which is translated into '$'
324#       - ${varname} is accepted.
325#       - varnames can be made out of letters, digits and the character '_'
326# XXX With COMMAND.COM you can use any characters in a variable name,
327# XXX except '^|<>='.
328
329def expandvars(path):
330    """Expand shell variables of form $var and ${var}.
331
332    Unknown variables are left unchanged."""
333    if '$' not in path:
334        return path
335    import string
336    varchars = string.letters + string.digits + '_-'
337    res = ''
338    index = 0
339    pathlen = len(path)
340    while index < pathlen:
341        c = path[index]
342        if c == '\'':   # no expansion within single quotes
343            path = path[index + 1:]
344            pathlen = len(path)
345            try:
346                index = path.index('\'')
347                res = res + '\'' + path[:index + 1]
348            except ValueError:
349                res = res + path
350                index = pathlen - 1
351        elif c == '$':  # variable or '$$'
352            if path[index + 1:index + 2] == '$':
353                res = res + c
354                index = index + 1
355            elif path[index + 1:index + 2] == '{':
356                path = path[index+2:]
357                pathlen = len(path)
358                try:
359                    index = path.index('}')
360                    var = path[:index]
361                    if var in os.environ:
362                        res = res + os.environ[var]
363                except ValueError:
364                    res = res + path
365                    index = pathlen - 1
366            else:
367                var = ''
368                index = index + 1
369                c = path[index:index + 1]
370                while c != '' and c in varchars:
371                    var = var + c
372                    index = index + 1
373                    c = path[index:index + 1]
374                if var in os.environ:
375                    res = res + os.environ[var]
376                if c != '':
377                    res = res + c
378        else:
379            res = res + c
380        index = index + 1
381    return res
382
383
384# Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B.
385
386def normpath(path):
387    """Normalize path, eliminating double slashes, etc."""
388    path = path.replace('\\', '/')
389    prefix, path = splitdrive(path)
390    while path[:1] == '/':
391        prefix = prefix + '/'
392        path = path[1:]
393    comps = path.split('/')
394    i = 0
395    while i < len(comps):
396        if comps[i] == '.':
397            del comps[i]
398        elif comps[i] == '..' and i > 0 and comps[i-1] not in ('', '..'):
399            del comps[i-1:i+1]
400            i = i - 1
401        elif comps[i] == '' and i > 0 and comps[i-1] != '':
402            del comps[i]
403        else:
404            i = i + 1
405    # If the path is now empty, substitute '.'
406    if not prefix and not comps:
407        comps.append('.')
408    return prefix + '/'.join(comps)
409
410
411# Return an absolute path.
412def abspath(path):
413    """Return the absolute version of a path"""
414    if not isabs(path):
415        path = join(os.getcwd(), path)
416    return normpath(path)
417
418# realpath is a no-op on systems without islink support
419realpath = abspath
420
421supports_unicode_filenames = False
422