Lib/os2emxpath.py

   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