files/usr/share/python-support/sipb-xen-base/invirt/common.py

   1 import unittest
   2 from fcntl import flock, LOCK_EX, LOCK_UN
   3 from os import remove
   4
   5 class struct(object):
   6     'A simple namespace object.'
   7     def __init__(self, d = {}, **kwargs):
   8         'd is the dictionary to update my __dict__ with.'
   9         self.__dict__.update(d)
  10         self.__dict__.update(kwargs)
  11
  12 def dicts2struct(x):
  13     """
  14     Given a tree of lists/dicts, perform a deep traversal to transform all the
  15     dicts to structs.
  16     """
  17     if type(x) == dict:
  18         return struct((k, dicts2struct(v)) for k,v in x.iteritems())
  19     elif type(x) == list:
  20         return [dicts2struct(v) for v in x]
  21     else:
  22         return x
  23
  24 #
  25 # Hacks to work around lack of Python 2.5's `with` statement.
  26 #
  27
  28 def with_closing(rsrc):
  29     "Utility to emulate Python 2.5's `with closing(rsrc)` context manager."
  30     def wrapper(func):
  31         try: return func(rsrc)
  32         finally: rsrc.close()
  33     return wrapper
  34
  35 def with_lock_file(path):
  36     """
  37     Context manager for lock files.  Example:
  38
  39     @with_lock_file('/tmp/mylock')
  40     def input():
  41         print 'locked'
  42         return raw_input()
  43     # decorator is executed immediately
  44     print input # prints the input text
  45     """
  46     def wrapper(func):
  47         @with_closing(file(path, 'w'))
  48         def g(f):
  49             flock(f, LOCK_EX)
  50             try: return func()
  51             finally: flock(f, LOCK_UN)
  52         remove(path)
  53         return g
  54     return wrapper
  55
  56 #
  57 # Tests.
  58 #
  59
  60 class common_tests(unittest.TestCase):
  61     def test_dicts2structs(self):
  62         dicts = {
  63                 'atom': 0,
  64                 'dict': { 'atom': 'atom', 'list': [1,2,3] },
  65                 'list': [ 'atom', {'key': 'value'} ]
  66                 }
  67         structs = dicts2struct(dicts)
  68         self.assertEqual(structs.atom,        dicts['atom'])
  69         self.assertEqual(structs.dict.atom,   dicts['dict']['atom'])
  70         self.assertEqual(structs.dict.list,   dicts['dict']['list'])
  71         self.assertEqual(structs.list[0],     dicts['list'][0])
  72         self.assertEqual(structs.list[1].key, dicts['list'][1]['key'])
  73
  74 if __name__ == '__main__':
  75     unittest.main()