Package horizons :: Package util :: Package python :: Module weakmethod
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Source Code for Module horizons.util.python.weakmethod

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 4  # This file is part of Unknown Horizons. 
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14  # GNU General Public License for more details. 
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18  # Free Software Foundation, Inc., 
19  # 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA 
20  # ################################################### 
21   
22  import types 
23  import weakref 
24   
25   
26 -class WeakMethod:
27 - def __init__(self, function):
28 assert callable(function) 29 30 if isinstance(function, types.MethodType) and function.__self__ is not None: 31 self.function = function.__func__ 32 self.instance = weakref.ref(function.__self__) 33 else: 34 self.function = function 35 self.instance = None
36
37 - def __call__(self, *args, **kwargs):
38 if self.instance is None: 39 return self.function(*args, **kwargs) 40 elif self.instance() is not None: 41 return self.function(self.instance(), *args, **kwargs) 42 else: 43 raise ReferenceError("Instance: {} Function: {} Function from module: {}" 44 .format(self.instance(), self.function, self.function.__module__))
45
46 - def __eq__(self, other):
47 if isinstance(other, WeakMethod): 48 if self.function != other.function: 49 return False 50 # check also if either instance is None or else if instances are equal 51 if self.instance is None: 52 return other.instance is None 53 else: 54 return self.instance() == other.instance() 55 elif callable(other): 56 return self == WeakMethod(other) 57 else: 58 return False
59
60 - def __ne__(self, other):
61 return not self.__eq__(other)
62
63 - def __hash__(self):
64 return hash((self.instance, self.function))
65
66 - def __str__(self):
67 return str(self.function)
68