1 # Module 'os2emxpath' -- common operations on OS/2 pathnames

     2 """Common pathname manipulations, OS/2 EMX version.

     3 

     4 Instead of importing this module directly, import os and refer to this

     5 module as os.path.

     6 """

     7 

     8 import os

     9 import stat

    10 

    11 __all__ = ["normcase","isabs","join","splitdrive","split","splitext",

    12            "basename","dirname","commonprefix","getsize","getmtime",

    13            "getatime","getctime", "islink","exists","lexists","isdir","isfile",

    14            "ismount","walk","expanduser","expandvars","normpath","abspath",

    15            "splitunc","curdir","pardir","sep","pathsep","defpath","altsep",

    16            "extsep","devnull","realpath","supports_unicode_filenames"]

    17 

    18 # strings representing various path-related bits and pieces

    19 curdir = '.'

    20 pardir = '..'

    21 extsep = '.'

    22 sep = '/'

    23 altsep = '\\'

    24 pathsep = ';'

    25 defpath = '.;C:\\bin'

    26 devnull = 'nul'

    27 

    28 # Normalize the case of a pathname and map slashes to backslashes.

    29 # Other normalizations (such as optimizing '../' away) are not done

    30 # (this is done by normpath).

    31 

    32 def normcase(s):

    33     """Normalize case of pathname.

    34 

    35     Makes all characters lowercase and all altseps into seps."""

    36     return s.replace('\\', '/').lower()

    37 

    38 

    39 # Return whether a path is absolute.

    40 # Trivial in Posix, harder on the Mac or MS-DOS.

    41 # For DOS it is absolute if it starts with a slash or backslash (current

    42 # volume), or if a pathname after the volume letter and colon / UNC resource

    43 # starts with a slash or backslash.

    44 

    45 def isabs(s):

    46     """Test whether a path is absolute"""

    47     s = splitdrive(s)[1]

    48     return s != '' and s[:1] in '/\\'

    49 

    50 

    51 # Join two (or more) paths.

    52 

    53 def join(a, *p):

    54     """Join two or more pathname components, inserting sep as needed"""

    55     path = a

    56     for b in p:

    57         if isabs(b):

    58             path = b

    59         elif path == '' or path[-1:] in '/\\:':

    60             path = path + b

    61         else:

    62             path = path + '/' + b

    63     return path

    64 

    65 

    66 # Split a path in a drive specification (a drive letter followed by a

    67 # colon) and the path specification.

    68 # It is always true that drivespec + pathspec == p

    69 def splitdrive(p):

    70     """Split a pathname into drive and path specifiers. Returns a 2-tuple

    71 "(drive,path)";  either part may be empty"""

    72     if p[1:2] == ':':

    73         return p[0:2], p[2:]

    74     return '', p

    75 

    76 

    77 # Parse UNC paths

    78 def splitunc(p):

    79     """Split a pathname into UNC mount point and relative path specifiers.

    80 

    81     Return a 2-tuple (unc, rest); either part may be empty.

    82     If unc is not empty, it has the form '//host/mount' (or similar

    83     using backslashes).  unc+rest is always the input path.

    84     Paths containing drive letters never have an UNC part.

    85     """

    86     if p[1:2] == ':':

    87         return '', p # Drive letter present

    88     firstTwo = p[0:2]

    89     if firstTwo == '/' * 2 or firstTwo == '\\' * 2:

    90         # is a UNC path:

    91         # vvvvvvvvvvvvvvvvvvvv equivalent to drive letter

    92         # \\machine\mountpoint\directories...

    93         #           directory ^^^^^^^^^^^^^^^

    94         normp = normcase(p)

    95         index = normp.find('/', 2)

    96         if index == -1:

    97             ##raise RuntimeError, 'illegal UNC path: "' + p + '"'

    98             return ("", p)

    99         index = normp.find('/', index + 1)

   100         if index == -1:

   101             index = len(p)

   102         return p[:index], p[index:]

   103     return '', p

   104 

   105 

   106 # Split a path in head (everything up to the last '/') and tail (the

   107 # rest).  After the trailing '/' is stripped, the invariant

   108 # join(head, tail) == p holds.

   109 # The resulting head won't end in '/' unless it is the root.

   110 

   111 def split(p):

   112     """Split a pathname.

   113 

   114     Return tuple (head, tail) where tail is everything after the final slash.

   115     Either part may be empty."""

   116 

   117     d, p = splitdrive(p)

   118     # set i to index beyond p's last slash

   119     i = len(p)

   120     while i and p[i-1] not in '/\\':

   121         i = i - 1

   122     head, tail = p[:i], p[i:]  # now tail has no slashes

   123     # remove trailing slashes from head, unless it's all slashes

   124     head2 = head

   125     while head2 and head2[-1] in '/\\':

   126         head2 = head2[:-1]

   127     head = head2 or head

   128     return d + head, tail

   129 

   130 

   131 # Split a path in root and extension.

   132 # The extension is everything starting at the last dot in the last

   133 # pathname component; the root is everything before that.

   134 # It is always true that root + ext == p.

   135 

   136 def splitext(p):

   137     """Split the extension from a pathname.

   138 

   139     Extension is everything from the last dot to the end.

   140     Return (root, ext), either part may be empty."""

   141     root, ext = '', ''

   142     for c in p:

   143         if c in ['/','\\']:

   144             root, ext = root + ext + c, ''

   145         elif c == '.':

   146             if ext:

   147                 root, ext = root + ext, c

   148             else:

   149                 ext = c

   150         elif ext:

   151             ext = ext + c

   152         else:

   153             root = root + c

   154     return root, ext

   155 

   156 

   157 # Return the tail (basename) part of a path.

   158 

   159 def basename(p):

   160     """Returns the final component of a pathname"""

   161     return split(p)[1]

   162 

   163 

   164 # Return the head (dirname) part of a path.

   165 

   166 def dirname(p):

   167     """Returns the directory component of a pathname"""

   168     return split(p)[0]

   169 

   170 

   171 # Return the longest prefix of all list elements.

   172 

   173 def commonprefix(m):

   174     "Given a list of pathnames, returns the longest common leading component"

   175     if not m: return ''

   176     s1 = min(m)

   177     s2 = max(m)

   178     n = min(len(s1), len(s2))

   179     for i in xrange(n):

   180         if s1[i] != s2[i]:

   181             return s1[:i]

   182     return s1[:n]

   183 

   184 

   185 # Get size, mtime, atime of files.

   186 

   187 def getsize(filename):

   188     """Return the size of a file, reported by os.stat()"""

   189     return os.stat(filename).st_size

   190 

   191 def getmtime(filename):

   192     """Return the last modification time of a file, reported by os.stat()"""

   193     return os.stat(filename).st_mtime

   194 

   195 def getatime(filename):

   196     """Return the last access time of a file, reported by os.stat()"""

   197     return os.stat(filename).st_atime

   198 

   199 def 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 

   206 def 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 

   214 def 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 lexists = exists

   223 

   224 

   225 # Is a path a directory?

   226 

   227 def isdir(path):

   228     """Test whether a path is a directory"""

   229     try:

   230         st = os.stat(path)

   231     except os.error:

   232         return False

   233     return stat.S_ISDIR(st.st_mode)

   234 

   235 

   236 # Is a path a regular file?

   237 # This follows symbolic links, so both islink() and isdir() can be true

   238 # for the same path.

   239 

   240 def isfile(path):

   241     """Test whether a path is a regular file"""

   242     try:

   243         st = os.stat(path)

   244     except os.error:

   245         return False

   246     return stat.S_ISREG(st.st_mode)

   247 

   248 

   249 # Is a path a mount point?  Either a root (with or without drive letter)

   250 # or an UNC path with at most a / or \ after the mount point.

   251 

   252 def ismount(path):

   253     """Test whether a path is a mount point (defined as root of drive)"""

   254     unc, rest = splitunc(path)

   255     if unc:

   256         return rest in ("", "/", "\\")

   257     p = splitdrive(path)[1]

   258     return len(p) == 1 and p[0] in '/\\'

   259 

   260 

   261 # Directory tree walk.

   262 # For each directory under top (including top itself, but excluding

   263 # '.' and '..'), func(arg, dirname, filenames) is called, where

   264 # dirname is the name of the directory and filenames is the list

   265 # of files (and subdirectories etc.) in the directory.

   266 # The func may modify the filenames list, to implement a filter,

   267 # or to impose a different order of visiting.

   268 

   269 def walk(top, func, arg):

   270     """Directory tree walk whth callback function.

   271 

   272     walk(top, func, arg) calls func(arg, d, files) for each directory d

   273     in the tree rooted at top (including top itself); files is a list

   274     of all the files and subdirs in directory d."""

   275     try:

   276         names = os.listdir(top)

   277     except os.error:

   278         return

   279     func(arg, top, names)

   280     exceptions = ('.', '..')

   281     for name in names:

   282         if name not in exceptions:

   283             name = join(top, name)

   284             if isdir(name):

   285                 walk(name, func, arg)

   286 

   287 

   288 # Expand paths beginning with '~' or '~user'.

   289 # '~' means $HOME; '~user' means that user's home directory.

   290 # If the path doesn't begin with '~', or if the user or $HOME is unknown,

   291 # the path is returned unchanged (leaving error reporting to whatever

   292 # function is called with the expanded path as argument).

   293 # See also module 'glob' for expansion of *, ? and [...] in pathnames.

   294 # (A function should also be defined to do full *sh-style environment

   295 # variable expansion.)

   296 

   297 def expanduser(path):

   298     """Expand ~ and ~user constructs.

   299 

   300     If user or $HOME is unknown, do nothing."""

   301     if path[:1] != '~':

   302         return path

   303     i, n = 1, len(path)

   304     while i < n and path[i] not in '/\\':

   305         i = i + 1

   306     if i == 1:

   307         if 'HOME' in os.environ:

   308             userhome = os.environ['HOME']

   309         elif not 'HOMEPATH' in os.environ:

   310             return path

   311         else:

   312             try:

   313                 drive = os.environ['HOMEDRIVE']

   314             except KeyError:

   315                 drive = ''

   316             userhome = join(drive, os.environ['HOMEPATH'])

   317     else:

   318         return path

   319     return userhome + path[i:]

   320 

   321 

   322 # Expand paths containing shell variable substitutions.

   323 # The following rules apply:

   324 #       - no expansion within single quotes

   325 #       - no escape character, except for '$$' which is translated into '$'

   326 #       - ${varname} is accepted.

   327 #       - varnames can be made out of letters, digits and the character '_'

   328 # XXX With COMMAND.COM you can use any characters in a variable name,

   329 # XXX except '^|<>='.

   330 

   331 def expandvars(path):

   332     """Expand shell variables of form $var and ${var}.

   333 

   334     Unknown variables are left unchanged."""

   335     if '$' not in path:

   336         return path

   337     import string

   338     varchars = string.letters + string.digits + '_-'

   339     res = ''

   340     index = 0

   341     pathlen = len(path)

   342     while index < pathlen:

   343         c = path[index]

   344         if c == '\'':   # no expansion within single quotes

   345             path = path[index + 1:]

   346             pathlen = len(path)

   347             try:

   348                 index = path.index('\'')

   349                 res = res + '\'' + path[:index + 1]

   350             except ValueError:

   351                 res = res + path

   352                 index = pathlen - 1

   353         elif c == '$':  # variable or '$$'

   354             if path[index + 1:index + 2] == '$':

   355                 res = res + c

   356                 index = index + 1

   357             elif path[index + 1:index + 2] == '{':

   358                 path = path[index+2:]

   359                 pathlen = len(path)

   360                 try:

   361                     index = path.index('}')

   362                     var = path[:index]

   363                     if var in os.environ:

   364                         res = res + os.environ[var]

   365                 except ValueError:

   366                     res = res + path

   367                     index = pathlen - 1

   368             else:

   369                 var = ''

   370                 index = index + 1

   371                 c = path[index:index + 1]

   372                 while c != '' and c in varchars:

   373                     var = var + c

   374                     index = index + 1

   375                     c = path[index:index + 1]

   376                 if var in os.environ:

   377                     res = res + os.environ[var]

   378                 if c != '':

   379                     res = res + c

   380         else:

   381             res = res + c

   382         index = index + 1

   383     return res

   384 

   385 

   386 # Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B.

   387 

   388 def normpath(path):

   389     """Normalize path, eliminating double slashes, etc."""

   390     path = path.replace('\\', '/')

   391     prefix, path = splitdrive(path)

   392     while path[:1] == '/':

   393         prefix = prefix + '/'

   394         path = path[1:]

   395     comps = path.split('/')

   396     i = 0

   397     while i < len(comps):

   398         if comps[i] == '.':

   399             del comps[i]

   400         elif comps[i] == '..' and i > 0 and comps[i-1] not in ('', '..'):

   401             del comps[i-1:i+1]

   402             i = i - 1

   403         elif comps[i] == '' and i > 0 and comps[i-1] != '':

   404             del comps[i]

   405         else:

   406             i = i + 1

   407     # If the path is now empty, substitute '.'

   408     if not prefix and not comps:

   409         comps.append('.')

   410     return prefix + '/'.join(comps)

   411 

   412 

   413 # Return an absolute path.

   414 def abspath(path):

   415     """Return the absolute version of a path"""

   416     if not isabs(path):

   417         path = join(os.getcwd(), path)

   418     return normpath(path)

   419 

   420 # realpath is a no-op on systems without islink support

   421 realpath = abspath

   422 

   423 supports_unicode_filenames = False