Source Code for Module oort.util.code

  1  #======================================================================= 
  2   
  3   
  4 -class autosuper(type): 
  5      """ 
  6      Use this as a metaclass for types to set the magic attribute '__super' on 
  7      them. When this is accessed through self the result is an object 
  8      constructed as if super(ThisType, self) had been called. (Makes it a little 
  9      bit more like in Python 3, where super() will work like this attribute.) 
 10      """ 
 11 -    def __init__(cls, name, bases, members): 
 12          super(autosuper, cls).__init__(name, bases, members) 
 13          setattr(cls, "_%s__super" % name, super(cls)) 
 14   
 15   
 16  #======================================================================= 
 17   
 18   
 19 -def init_slots(obj, *args, **kwargs): 
 20      data = dict(zip(obj.__slots__, args)) 
 21      data.update(kwargs) 
 22      for a in obj.__slots__: 
 23          setattr(obj, a, data.get(a, None)) 
 24   
 25 -class SlotStruct(object): 
 26      """ 
 27      Base class for making "struct" types with members defined by their 
 28      __slots__ value. Example: 
 29   
 30          >>> class Item(SlotStruct): 
 31          ...     __slots__ = 'first', 'last' 
 32   
 33          >>> item1 = Item(first='a', last='b') 
 34          >>> item1.first, item1.last 
 35          ('a', 'b') 
 36   
 37          >>> item1.middle = '-' 
 38          Traceback (most recent call last): 
 39          ... 
 40          AttributeError: 'Item' object has no attribute 'middle' 
 41   
 42          >>> item2 = Item('a', 'b') 
 43          >>> assert (item1.first, item1.last) == (item2.first, item2.last) 
 44   
 45          >>> assert item1.make_dict() == {'first': 'a', 'last': 'b'} 
 46   
 47      """ 
 48      __slots__ = () 
 49 -    def __init__(self, *args, **kwargs): 
 50          init_slots(self, *args, **kwargs) 
 51 -    def __str__(self): 
 52          return "%s instance with %s" % (type(self).__name__, str(self.make_dict())) 
 53 -    def make_dict(self): 
 54          return dict([(a, getattr(self, a)) for a in self.__slots__]) 
 55   
 56   
 57  #======================================================================= 
 58   
 59   
 60 -def property_with_setter(fset): 
 61      attr = '_%s' % fset.func_name 
 62      return property(lambda self: getattr(self, attr), 
 63              fset, doc=fset.__doc__) 
 64   
 65   
 66  #======================================================================= 
 67   
 68   
 69 -def call(caller, *args): 
 70      def decorator(decorated): 
 71          callArgs = [(arg, decorated)[arg is call] for arg in args] 
 72          caller(*callArgs) 
 73          return call 
 74      return decorator 
 75   
 76   
 77  #======================================================================= 
 78   
 79   
 80 -class BooleanDecorator(object): 
 81      """ 
 82      A documentation helper. Usage: 
 83   
 84          >>> contract = BooleanDecorator('interface') 
 85          >>> class T: 
 86          ...     @contract.interface 
 87          ...     def action(self): raise NotImplementedError 
 88          ... 
 89          >>> assert T.action.interface == True 
 90      """ 
 91   
 92      __slots__ = ('attributes') 
 93   
 94 -    def __init__(self, *args): 
 95          self.attributes = args 
 96   
 97 -    def __getattr__(self, name): 
 98          if name not in self.attributes: 
 99              raise Exception("Unknown attribute: %s" % name) 
100          def decorator(func): 
101              setattr(func, name, True) 
102              return func 
103          return decorator 
104   
105  contract = BooleanDecorator('template_method', 'default_method', 'helper', 'state_change') 
106   
107   
108 -def attrs(**kwargs): 
109      """ 
110      Generic decorator for setting attributes. Usage: 
111   
112          >>> @attrs(value="A value", thing=None, other=True) 
113          ... def f(): pass 
114          ... 
115          >>> assert f.value == "A value" 
116          >>> assert f.thing is None 
117          >>> assert f.other is True 
118      """ 
119      def decorator(func): 
120          # TODO: or just func.__dict__.update(kwargs) 
121          for key, value in kwargs.items(): 
122              setattr(func, key, value) 
123          return func 
124      return decorator 
125