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 must be implemented by the child classes. 
105   
106      """ 
107      raise NotImplementedError 
108   
109   
110 -def ContainerToDicts(container): 
111    """Convert the elements of a container to standard Python types. 
112   
113    This method converts a container with elements to standard Python types. If 
114    the input container is of the type C{dict}, only its values are touched. 
115    Those values, as well as all elements of input sequences, must support a 
116    C{ToDict} method returning a serialized version. 
117   
118    @type container: dict or sequence (see L{_SEQUENCE_TYPES}) 
119   
120    """ 
121    if isinstance(container, dict): 
122      ret = dict([(k, v.ToDict()) for k, v in container.items()]) 
123    elif isinstance(container, _SEQUENCE_TYPES): 
124      ret = [elem.ToDict() for elem in container] 
125    else: 
126      raise TypeError("Unknown container type '%s'" % type(container)) 
127   
128    return ret 
129   
130   
131 -def ContainerFromDicts(source, c_type, e_type): 
132    """Convert a container from standard python types. 
133   
134    This method converts a container with standard Python types to objects. If 
135    the container is a dict, we don't touch the keys, only the values. 
136   
137    @type source: None, dict or sequence (see L{_SEQUENCE_TYPES}) 
138    @param source: Input data 
139    @type c_type: type class 
140    @param c_type: Desired type for returned container 
141    @type e_type: element type class 
142    @param e_type: Item type for elements in returned container (must have a 
143      C{FromDict} class method) 
144   
145    """ 
146    if not isinstance(c_type, type): 
147      raise TypeError("Container type '%s' is not a type" % type(c_type)) 
148   
149    if source is None: 
150      source = c_type() 
151   
152    if c_type is dict: 
153      ret = dict([(k, e_type.FromDict(v)) for k, v in source.items()]) 
154    elif c_type in _SEQUENCE_TYPES: 
155      ret = c_type(map(e_type.FromDict, source)) 
156    else: 
157      raise TypeError("Unknown container type '%s'" % c_type) 
158   
159    return ret 
160