chrome/common/extensions/docs/server2/path_util.py

   1 # Copyright 2013 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import posixpath
   6
   7
   8 # TODO(kalman): Write a Path class and use that everywhere rather than a
   9 # utility class.
  10
  11
  12 def IsDirectory(path):
  13   '''Returns whether |path| should be considered a directory.
  14   '''
  15   # This assertion is sprinkled throughout the code base.
  16   AssertIsValid(path)
  17   return path in ('', '.', '..') or path.endswith('/') or path.endswith('/..')
  18
  19
  20 def IsValid(path):
  21   '''Returns whether |path| is a valid path for the purposes of the docserver.
  22   Paths may not start with /, must be posix paths, and for sanity shouldn't
  23   repeat the path separator //.
  24   '''
  25   return not path.startswith('/') and not '\\' in path and not '//' in path
  26
  27
  28 def AssertIsValid(path):
  29   assert IsValid(path), 'Path "%s" is invalid' % path
  30
  31
  32 def Join(*paths):
  33   assert all(IsValid(path) for path in paths), paths
  34   return posixpath.join(*paths)
  35
  36
  37 def SplitParent(path):
  38   '''Returns the parent directory and base name of |path| in a tuple.
  39   Any trailing slash of |path| is preserved, such that the parent of
  40   '/hello/world/' is '/hello' and the base is 'world/'.
  41   '''
  42   parent, base = posixpath.split(path.rstrip('/'))
  43   if path.endswith('/'):
  44     base += '/'
  45   return parent, base
  46
  47
  48 def Split(path):
  49   '''Returns a list of the directories and filename in a path. 'p1/p2/p3'
  50   will return ['p1/', 'p2/', 'p3'].
  51   '''
  52   AssertIsValid(path)
  53   names = [name + '/' for name in path.rstrip('/').split('/')]
  54   if names and not path.endswith('/'):
  55     names[-1] = names[-1][:-1]
  56   return names
  57
  58
  59 def ToDirectory(path):
  60   '''Returns a string representing |path| as a directory, that is,
  61   IsDirectory(result) is True (and does not fail assertions). If |path| is
  62   already a directory then this is a no-op.
  63   '''
  64   return path if IsDirectory(path) else (path + '/')
  65
  66
  67 def AssertIsDirectory(path):
  68   assert IsDirectory(path), '"%s" is not a directory' % path
  69
  70
  71 def AssertIsFile(path):
  72   assert not IsDirectory(path), '"%s" is not a file' % path
  73
  74 def Segment(path):
  75   '''Yields a tuple (url, file) for directory split pairs.
  76   For example, if we split the path 'foo/bar/baz', it will yield:
  77   ('', 'foo/bar/baz'), ('foo', "bar/baz'), ('foo/bar', 'baz'),
  78   ('foo/bar/baz', '')
  79   '''
  80   AssertIsValid(path)
  81
  82   last_path = ''
  83   yield (last_path, path)
  84
  85   for segment in (segment for segment in path.split('/') if segment != ''):
  86     last_path = posixpath.join(last_path, segment)
  87     rel_path = posixpath.relpath(path, last_path)
  88
  89     # Don't let relpath say the filename is '.'
  90     if rel_path == '.':
  91       rel_path = ''
  92     else:
  93       last_path = ToDirectory(last_path)
  94
  95     yield (last_path, rel_path)