Source Code for Module ganeti.compat

  1  # 
  2  # 
  3   
  4  # Copyright (C) 2010, 2011 Google Inc. 
  5  # 
  6  # This program is free software; you can redistribute it and/or modify 
  7  # it under the terms of the GNU General Public License as published by 
  8  # the Free Software Foundation; either version 2 of the License, or 
  9  # (at your option) any later version. 
 10  # 
 11  # This program is distributed in the hope that it will be useful, but 
 12  # WITHOUT ANY WARRANTY; without even the implied warranty of 
 13  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
 14  # General Public License for more details. 
 15  # 
 16  # You should have received a copy of the GNU General Public License 
 17  # along with this program; if not, write to the Free Software 
 18  # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 
 19  # 02110-1301, USA. 
 20   
 21   
 22  """Module containing backported language/library functionality. 
 23   
 24  """ 
 25   
 26  import itertools 
 27  import operator 
 28   
 29  try: 
 30    # pylint: disable=F0401 
 31    import functools 
 32  except ImportError: 
 33    functools = None 
 34   
 35  try: 
 36    # pylint: disable=F0401 
 37    import roman 
 38  except ImportError: 
 39    roman = None 
 40   
 41   
 42  # compat.md5_hash and compat.sha1_hash can be called to generate and md5 and a 
 43  # sha1 hashing modules, under python 2.4, 2.5 and 2.6, even though some changes 
 44  # went on. compat.sha1 is python-version specific and is used for python 
 45  # modules (hmac, for example) which have changed their behavior as well from 
 46  # one version to the other. 
 47  try: 
 48    # Yes, these don't always exist, that's why we're testing 
 49    # Yes, we're not using the imports in this module. 
 50    from hashlib import md5 as md5_hash # pylint: disable=W0611,E0611,F0401 
 51    from hashlib import sha1 as sha1_hash # pylint: disable=W0611,E0611,F0401 
 52    # this additional version is needed for compatibility with the hmac module 
 53    sha1 = sha1_hash 
 54  except ImportError: 
 55    from md5 import new as md5_hash 
 56    import sha 
 57    sha1 = sha 
 58    sha1_hash = sha.new 
 59   
 60   
 61 -def _all(seq): 
 62    """Returns True if all elements in the iterable are True. 
 63   
 64    """ 
 65    for _ in itertools.ifilterfalse(bool, seq): 
 66      return False 
 67    return True 
 68   
 69   
 70 -def _any(seq): 
 71    """Returns True if any element of the iterable are True. 
 72   
 73    """ 
 74    for _ in itertools.ifilter(bool, seq): 
 75      return True 
 76    return False 
 77   
 78   
 79  try: 
 80    # pylint: disable=E0601 
 81    # pylint: disable=W0622 
 82    all = all 
 83  except NameError: 
 84    all = _all 
 85   
 86  try: 
 87    # pylint: disable=E0601 
 88    # pylint: disable=W0622 
 89    any = any 
 90  except NameError: 
 91    any = _any 
 92   
 93   
 94 -def partition(seq, pred=bool): # pylint: disable=W0622 
 95    """Partition a list in two, based on the given predicate. 
 96   
 97    """ 
 98    return (list(itertools.ifilter(pred, seq)), 
 99            list(itertools.ifilterfalse(pred, seq))) 
100   
101   
102  # Even though we're using Python's built-in "partial" function if available, 
103  # this one is always defined for testing. 
104 -def _partial(func, *args, **keywords): # pylint: disable=W0622 
105    """Decorator with partial application of arguments and keywords. 
106   
107    This function was copied from Python's documentation. 
108   
109    """ 
110    def newfunc(*fargs, **fkeywords): 
111      newkeywords = keywords.copy() 
112      newkeywords.update(fkeywords) 
113      return func(*(args + fargs), **newkeywords) # pylint: disable=W0142 
114   
115    newfunc.func = func 
116    newfunc.args = args 
117    newfunc.keywords = keywords 
118    return newfunc 
119   
120   
121  if functools is None: 
122    partial = _partial 
123  else: 
124    partial = functools.partial 
125   
126   
127 -def TryToRoman(val, convert=True): 
128    """Try to convert a value to roman numerals 
129   
130    If the roman module could be loaded convert the given value to a roman 
131    numeral. Gracefully fail back to leaving the value untouched. 
132   
133    @type val: integer 
134    @param val: value to convert 
135    @type convert: boolean 
136    @param convert: if False, don't try conversion at all 
137    @rtype: string or typeof(val) 
138    @return: roman numeral for val, or val if conversion didn't succeed 
139   
140    """ 
141    if roman is not None and convert: 
142      try: 
143        return roman.toRoman(val) 
144      except roman.RomanError: 
145        return val 
146    else: 
147      return val 
148   
149   
150 -def UniqueFrozenset(seq): 
151    """Makes C{frozenset} from sequence after checking for duplicate elements. 
152   
153    @raise ValueError: When there are duplicate elements 
154   
155    """ 
156    if isinstance(seq, (list, tuple)): 
157      items = seq 
158    else: 
159      items = list(seq) 
160   
161    result = frozenset(items) 
162   
163    if len(items) != len(result): 
164      raise ValueError("Duplicate values found") 
165   
166    return result 
167   
168   
169  #: returns the first element of a list-like value 
170  fst = operator.itemgetter(0) 
171   
172  #: returns the second element of a list-like value 
173  snd = operator.itemgetter(1) 
174