Source Code for Module ganeti.compat

  1  # 
  2  # 
  3   
  4  # Copyright (C) 2010, 2011 Google Inc. 
  5  # All rights reserved. 
  6  # 
  7  # Redistribution and use in source and binary forms, with or without 
  8  # modification, are permitted provided that the following conditions are 
  9  # met: 
 10  # 
 11  # 1. Redistributions of source code must retain the above copyright notice, 
 12  # this list of conditions and the following disclaimer. 
 13  # 
 14  # 2. Redistributions in binary form must reproduce the above copyright 
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 16  # documentation and/or other materials provided with the distribution. 
 17  # 
 18  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 
 19  # IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 
 20  # TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
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 28  # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 29   
 30   
 31  """Module containing backported language/library functionality. 
 32   
 33  """ 
 34   
 35  import itertools 
 36  import operator 
 37   
 38  try: 
 39    # pylint: disable=F0401 
 40    import functools 
 41  except ImportError: 
 42    functools = None 
 43   
 44  try: 
 45    # pylint: disable=F0401 
 46    import roman 
 47  except ImportError: 
 48    roman = None 
 49   
 50   
 51  # compat.md5_hash and compat.sha1_hash can be called to generate and md5 and a 
 52  # sha1 hashing modules, under python 2.4, 2.5 and 2.6, even though some changes 
 53  # went on. compat.sha1 is python-version specific and is used for python 
 54  # modules (hmac, for example) which have changed their behavior as well from 
 55  # one version to the other. 
 56  try: 
 57    # Yes, these don't always exist, that's why we're testing 
 58    # Yes, we're not using the imports in this module. 
 59    from hashlib import md5 as md5_hash # pylint: disable=W0611,E0611,F0401 
 60    from hashlib import sha1 as sha1_hash # pylint: disable=W0611,E0611,F0401 
 61    # this additional version is needed for compatibility with the hmac module 
 62    sha1 = sha1_hash 
 63  except ImportError: 
 64    from md5 import new as md5_hash 
 65    import sha 
 66    sha1 = sha 
 67    sha1_hash = sha.new 
 68   
 69   
 70 -def _all(seq): 
 71    """Returns True if all elements in the iterable are True. 
 72   
 73    """ 
 74    for _ in itertools.ifilterfalse(bool, seq): 
 75      return False 
 76    return True 
 77   
 78   
 79 -def _any(seq): 
 80    """Returns True if any element of the iterable are True. 
 81   
 82    """ 
 83    for _ in itertools.ifilter(bool, seq): 
 84      return True 
 85    return False 
 86   
 87   
 88  try: 
 89    # pylint: disable=E0601 
 90    # pylint: disable=W0622 
 91    all = all 
 92  except NameError: 
 93    all = _all 
 94   
 95  try: 
 96    # pylint: disable=E0601 
 97    # pylint: disable=W0622 
 98    any = any 
 99  except NameError: 
100    any = _any 
101   
102   
103 -def partition(seq, pred=bool): # pylint: disable=W0622 
104    """Partition a list in two, based on the given predicate. 
105   
106    """ 
107    return (list(itertools.ifilter(pred, seq)), 
108            list(itertools.ifilterfalse(pred, seq))) 
109   
110   
111  # Even though we're using Python's built-in "partial" function if available, 
112  # this one is always defined for testing. 
113 -def _partial(func, *args, **keywords): # pylint: disable=W0622 
114    """Decorator with partial application of arguments and keywords. 
115   
116    This function was copied from Python's documentation. 
117   
118    """ 
119    def newfunc(*fargs, **fkeywords): 
120      newkeywords = keywords.copy() 
121      newkeywords.update(fkeywords) 
122      return func(*(args + fargs), **newkeywords) # pylint: disable=W0142 
123   
124    newfunc.func = func 
125    newfunc.args = args 
126    newfunc.keywords = keywords 
127    return newfunc 
128   
129   
130  if functools is None: 
131    partial = _partial 
132  else: 
133    partial = functools.partial 
134   
135   
136 -def TryToRoman(val, convert=True): 
137    """Try to convert a value to roman numerals 
138   
139    If the roman module could be loaded convert the given value to a roman 
140    numeral. Gracefully fail back to leaving the value untouched. 
141   
142    @type val: integer 
143    @param val: value to convert 
144    @type convert: boolean 
145    @param convert: if False, don't try conversion at all 
146    @rtype: string or typeof(val) 
147    @return: roman numeral for val, or val if conversion didn't succeed 
148   
149    """ 
150    if roman is not None and convert: 
151      try: 
152        return roman.toRoman(val) 
153      except roman.RomanError: 
154        return val 
155    else: 
156      return val 
157   
158   
159 -def UniqueFrozenset(seq): 
160    """Makes C{frozenset} from sequence after checking for duplicate elements. 
161   
162    @raise ValueError: When there are duplicate elements 
163   
164    """ 
165    if isinstance(seq, (list, tuple)): 
166      items = seq 
167    else: 
168      items = list(seq) 
169   
170    result = frozenset(items) 
171   
172    if len(items) != len(result): 
173      raise ValueError("Duplicate values found") 
174   
175    return result 
176   
177   
178  #: returns the first element of a list-like value 
179  fst = operator.itemgetter(0) 
180   
181  #: returns the second element of a list-like value 
182  snd = operator.itemgetter(1) 
183