generated_tests/modules/utils.py

   1 # coding=utf-8
   2 # Copyright (c) 2014 Intel Corporation
   3
   4 # Permission is hereby granted, free of charge, to any person obtaining a copy
   5 # of this software and associated documentation files (the "Software"), to deal
   6 # in the Software without restriction, including without limitation the rights
   7 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   8 # copies of the Software, and to permit persons to whom the Software is
   9 # furnished to do so, subject to the following conditions:
  10
  11 # The above copyright notice and this permission notice shall be included in
  12 # all copies or substantial portions of the Software.
  13
  14 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  17 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  19 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  20 # SOFTWARE.
  21
  22 """Helper functions for test generators."""
  23
  24 import os
  25 import errno
  26 import functools
  27
  28
  29 def safe_makedirs(dirs):
  30     """A safe function for creating a directory tree.
  31
  32     This function wraps os.makedirs, and provides a couple of sanity checks,
  33     first, if the directory already exists it doesn't try to create it, and
  34     second if the directory comes into existence between the check and creation
  35     time (like if another generator creates it) then the exception will be
  36     caught.
  37
  38     """
  39     if not os.path.exists(dirs):
  40         try:
  41             os.makedirs(dirs)
  42         except OSError as e:
  43             if e.errno == errno.EEXIST:
  44                 pass
  45             else:
  46                 raise
  47
  48
  49 class lazy_property(object):
  50     """Decorator for lazy property loading.
  51
  52     A property decorated with this class will execute it's code the first time
  53     it's run, but will store the value after that. This is useful for values
  54     that are either 1) expensive to compute, or 2) need to be computed only
  55     once and then read multiple times
  56
  57     """
  58     def __init__(self, func):
  59         functools.wraps(func)
  60         self.__func = func
  61
  62     def __get__(self, obj, cls):
  63         if not obj:
  64             return self
  65         value = self.__func(obj)
  66         setattr(obj, self.__func.__name__, value)
  67         return value