Source Code for Module ganeti.outils

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 29   
 30  """Module for object related utils.""" 
 31   
 32   
 33  #: Supported container types for serialization/de-serialization (must be a 
 34  #: tuple as it's used as a parameter for C{isinstance}) 
 35  _SEQUENCE_TYPES = (list, tuple, set, frozenset) 
 36   
 37   
 38 -class AutoSlots(type): 
 39    """Meta base class for __slots__ definitions. 
 40   
 41    """ 
 42 -  def __new__(mcs, name, bases, attrs): 
 43      """Called when a class should be created. 
 44   
 45      @param mcs: The meta class 
 46      @param name: Name of created class 
 47      @param bases: Base classes 
 48      @type attrs: dict 
 49      @param attrs: Class attributes 
 50   
 51      """ 
 52      assert "__slots__" not in attrs, \ 
 53        "Class '%s' defines __slots__ when it should not" % name 
 54   
 55      attrs["__slots__"] = mcs._GetSlots(attrs) 
 56   
 57      return type.__new__(mcs, name, bases, attrs) 
 58   
 59    @classmethod 
 60 -  def _GetSlots(mcs, attrs): 
 61      """Used to get the list of defined slots. 
 62   
 63      @param attrs: The attributes of the class 
 64   
 65      """ 
 66      raise NotImplementedError 
 67   
 68   
 69 -class ValidatedSlots(object): 
 70    """Sets and validates slots. 
 71   
 72    """ 
 73    __slots__ = [] 
 74   
 75 -  def __init__(self, **kwargs): 
 76      """Constructor for BaseOpCode. 
 77   
 78      The constructor takes only keyword arguments and will set 
 79      attributes on this object based on the passed arguments. As such, 
 80      it means that you should not pass arguments which are not in the 
 81      __slots__ attribute for this class. 
 82   
 83      """ 
 84      slots = self.GetAllSlots() 
 85      for (key, value) in kwargs.items(): 
 86        if key not in slots: 
 87          raise TypeError("Object %s doesn't support the parameter '%s'" % 
 88                          (self.__class__.__name__, key)) 
 89        setattr(self, key, value) 
 90   
 91    @classmethod 
 92 -  def GetAllSlots(cls): 
 93      """Compute the list of all declared slots for a class. 
 94   
 95      """ 
 96      slots = [] 
 97      for parent in cls.__mro__: 
 98        slots.extend(getattr(parent, "__slots__", [])) 
 99      return slots 
100   
101 -  def Validate(self): 
102      """Validates the slots. 
103   
104      This method returns L{None} if the validation succeeds, or raises 
105      an exception otherwise. 
106   
107      @rtype: NoneType 
108      @return: L{None}, if the validation succeeds 
109   
110      @raise Exception: validation fails 
111   
112      This method must be implemented by the child classes. 
113   
114      """ 
115      raise NotImplementedError 
116   
117   
118 -def ContainerToDicts(container): 
119    """Convert the elements of a container to standard Python types. 
120   
121    This method converts a container with elements to standard Python types. If 
122    the input container is of the type C{dict}, only its values are touched. 
123    Those values, as well as all elements of input sequences, must support a 
124    C{ToDict} method returning a serialized version. 
125   
126    @type container: dict or sequence (see L{_SEQUENCE_TYPES}) 
127   
128    """ 
129    if isinstance(container, dict): 
130      ret = dict([(k, v.ToDict()) for k, v in container.items()]) 
131    elif isinstance(container, _SEQUENCE_TYPES): 
132      ret = [elem.ToDict() for elem in container] 
133    else: 
134      raise TypeError("Unknown container type '%s'" % type(container)) 
135   
136    return ret 
137   
138   
139 -def ContainerFromDicts(source, c_type, e_type): 
140    """Convert a container from standard python types. 
141   
142    This method converts a container with standard Python types to objects. If 
143    the container is a dict, we don't touch the keys, only the values. 
144   
145    @type source: None, dict or sequence (see L{_SEQUENCE_TYPES}) 
146    @param source: Input data 
147    @type c_type: type class 
148    @param c_type: Desired type for returned container 
149    @type e_type: element type class 
150    @param e_type: Item type for elements in returned container (must have a 
151      C{FromDict} class method) 
152   
153    """ 
154    if not isinstance(c_type, type): 
155      raise TypeError("Container type '%s' is not a type" % type(c_type)) 
156   
157    if source is None: 
158      source = c_type() 
159   
160    if c_type is dict: 
161      ret = dict([(k, e_type.FromDict(v)) for k, v in source.items()]) 
162    elif c_type in _SEQUENCE_TYPES: 
163      ret = c_type(map(e_type.FromDict, source)) 
164    else: 
165      raise TypeError("Unknown container type '%s'" % c_type) 
166   
167    return ret 
168