Source Code for Module cosmolopy.saveable

 1  """A Saveable class with methods to save and restore. 
 2   
 3  Saveable is designed to be subclassed to create new types of objects 
 4  that can easily be pickled and reloaded. 
 5  """ 
 6   
 7  import pickle 
 8   
 9 -class NullWriter: 
10      """Dummy file-like object that does nothing. 
11   
12      From 
13      http://stackoverflow.com/questions/1809958/hide-stderr-output-in-unit-tests 
14   
15      Used in Saveable. 
16      """ 
17 -    def write(self, s): 
18          pass 
19   
20   
21 -def loadSaveable(filename): 
22      """Return an instance of an object unpickled from a file. 
23      """ 
24      picfile = open(filename) 
25      loaded = pickle.load(picfile) 
26      picfile.close() 
27      return loaded 
28   
29 -class Saveable(object): 
30      """An object with methods to save and restore. 
31   
32      Unpickleable attributes will simply be deleted from the object. 
33      """ 
34   
35 -    def __init__(self, filename=None): 
36          if filename is not None: 
37              self.load(filename) 
38                     
39 -    def save(self, filename): 
40          """Save object to a file.""" 
41          picfile = open(filename, 'w') 
42          pickle.dump(self, picfile) 
43          picfile.close() 
44   
45 -    def load(self, filename): 
46          """Return an instance of an object unpickled from a file. 
47          """ 
48          picfile = open(filename) 
49          loaded = pickle.load(picfile) 
50          picfile.close() 
51          self.__dict__.update(loaded.__dict__) 
52          return self 
53   
54 -    def dumb_pickle_filter(self): 
55          """Filter out attributes that can't be pickled. 
56   
57          Returns a copy of dict with  
58          """ 
59          picfile = NullWriter() 
60          sdict = self.__dict__.copy() 
61          for k, v in sdict.items(): 
62              # Avoid self references (and thereby infinite recurion). 
63              if v is self: 
64                  del sdict[k] 
65                  continue 
66              # Remove any attributes that can't be pickled. 
67              try: 
68                  pickle.dump(v, picfile) 
69              except (TypeError, pickle.PicklingError) as err: 
70                  if hasattr(self, 'verbose') and self.verbose: 
71                      print "Won't pickle", k, type(v), ": " 
72                      print "'", err, "'" 
73                  del sdict[k] 
74          return sdict 
75 -    def __getstate__(self): 
76          """Prepare a state of pickling.""" 
77          return self.dumb_pickle_filter() 
78   
79 -    def __setstate__(self, dict): 
80          """Unpickle.""" 
81          self.__dict__.update(dict) 
82