chrome/common/extensions/docs/server2/test_file_system.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 from file_system import FileSystem, FileNotFoundError, StatInfo
   6 from future import Future
   7 from path_util import AssertIsValid, AssertIsDirectory, IsDirectory
   8
   9
  10 def MoveTo(base, obj):
  11   '''Returns an object as |obj| moved to |base|. That is,
  12   MoveTo('foo/bar', {'a': 'b'}) -> {'foo': {'bar': {'a': 'b'}}}
  13   '''
  14   AssertIsDirectory(base)
  15   result = {}
  16   leaf = result
  17   for k in base.rstrip('/').split('/'):
  18     leaf[k] = {}
  19     leaf = leaf[k]
  20   leaf.update(obj)
  21   return result
  22
  23
  24 def MoveAllTo(base, obj):
  25   '''Moves every value in |obj| to |base|. See MoveTo.
  26   '''
  27   result = {}
  28   for key, value in obj.iteritems():
  29     result[key] = MoveTo(base, value)
  30   return result
  31
  32
  33 def _List(file_system):
  34   '''Returns a list of '/' separated paths derived from |file_system|.
  35   For example, {'index.html': '', 'www': {'file.txt': ''}} would return
  36   ['index.html', 'www/file.txt'].
  37   '''
  38   assert isinstance(file_system, dict)
  39   result = {}
  40   def update_result(item, path):
  41     AssertIsValid(path)
  42     if isinstance(item, dict):
  43       if path != '':
  44         path += '/'
  45       result[path] = [p if isinstance(content, basestring) else (p + '/')
  46                       for p, content in item.iteritems()]
  47       for subpath, subitem in item.iteritems():
  48         update_result(subitem, path + subpath)
  49     elif isinstance(item, basestring):
  50       result[path] = item
  51     else:
  52       raise ValueError('Unsupported item type: %s' % type(item))
  53   update_result(file_system, '')
  54   return result
  55
  56
  57 class _StatTracker(object):
  58   '''Maintains the versions of paths in a file system. The versions of files
  59   are changed either by |Increment| or |SetVersion|. The versions of
  60   directories are derived from the versions of files within it.
  61   '''
  62
  63   def __init__(self):
  64     self._path_stats = {}
  65     self._global_stat = 0
  66
  67   def Increment(self, path=None, by=1):
  68     if path is None:
  69       self._global_stat += by
  70     else:
  71       self.SetVersion(path, self._path_stats.get(path, 0) + by)
  72
  73   def SetVersion(self, path, new_version):
  74     if IsDirectory(path):
  75       raise ValueError('Only files have an incrementable stat, '
  76                        'but "%s" is a directory' % path)
  77
  78     # Update version of that file.
  79     self._path_stats[path] = new_version
  80
  81     # Update all parent directory versions as well.
  82     slash_index = 0  # (deliberately including '' in the dir paths)
  83     while slash_index != -1:
  84       dir_path = path[:slash_index] + '/'
  85       self._path_stats[dir_path] = max(self._path_stats.get(dir_path, 0),
  86                                        new_version)
  87       if dir_path == '/':
  88         # Legacy support for '/' being the root of the file system rather
  89         # than ''. Eventually when the path normalisation logic is complete
  90         # this will be impossible and this logic will change slightly.
  91         self._path_stats[''] = self._path_stats['/']
  92       slash_index = path.find('/', slash_index + 1)
  93
  94   def GetVersion(self, path):
  95     return self._global_stat + self._path_stats.get(path, 0)
  96
  97
  98 class TestFileSystem(FileSystem):
  99   '''A FileSystem backed by an object. Create with an object representing file
 100   paths such that {'a': {'b': 'hello'}} will resolve Read('a/b') as 'hello',
 101   Read('a/') as ['b'], and Stat determined by a value incremented via
 102   IncrementStat.
 103   '''
 104
 105   def __init__(self, obj, relative_to=None, identity=None):
 106     assert obj is not None
 107     if relative_to is not None:
 108       obj = MoveTo(relative_to, obj)
 109     self._identity = identity or type(self).__name__
 110     self._path_values = _List(obj)
 111     self._stat_tracker = _StatTracker()
 112
 113   #
 114   # FileSystem implementation.
 115   #
 116
 117   def Read(self, paths, skip_not_found=False):
 118     for path in paths:
 119       if path not in self._path_values:
 120         if skip_not_found: continue
 121         return FileNotFoundError.RaiseInFuture(
 122             '%s not in %s' % (path, '\n'.join(self._path_values)))
 123     return Future(value=dict((k, v) for k, v in self._path_values.iteritems()
 124                              if k in paths))
 125
 126   def Refresh(self):
 127     return Future(value=())
 128
 129   def Stat(self, path):
 130     read_result = self.ReadSingle(path).Get()
 131     stat_result = StatInfo(str(self._stat_tracker.GetVersion(path)))
 132     if isinstance(read_result, list):
 133       stat_result.child_versions = dict(
 134           (file_result,
 135            str(self._stat_tracker.GetVersion('%s%s' % (path, file_result))))
 136           for file_result in read_result)
 137     return stat_result
 138
 139   #
 140   # Testing methods.
 141   #
 142
 143   def IncrementStat(self, path=None, by=1):
 144     self._stat_tracker.Increment(path, by=by)
 145
 146   def GetIdentity(self):
 147     return self._identity