Source Code for Module lastfm.mixins.cacheable

 1  #!/usr/bin/env python 
 2   
 3  __author__ = "Abhinav Sarkar <abhinav@abhinavsarkar.net>" 
 4  __version__ = "0.2" 
 5  __license__ = "GNU Lesser General Public License" 
 6   
 7  try: 
 8      from threading import Lock 
 9  except ImportError: 
10      from dummy_threading import Lock 
11       
12 -class Cacheable(object): 
13      registry = {} 
14      _lock = Lock() 
15   
16 -    def __new__(cls, *args, **kwds): 
17          subject = None 
18          if 'subject' in kwds and not cls.__name__.startswith('Weekly'): 
19              subject = kwds['subject'] 
20              #del kwds['subject'] 
21   
22          if 'bypass_registry' in kwds: 
23                  del kwds['bypass_registry'] 
24                  inst = object.__new__(cls) 
25                  inst.init(*args, **kwds) 
26                  return inst 
27   
28          key = cls._hash_func(*args, **kwds) 
29          if subject is not None: 
30              key = (hash(subject), key) 
31   
32          Cacheable._lock.acquire() 
33          try: 
34              inst, already_registered = Cacheable.register(object.__new__(cls), key) 
35              if not already_registered: 
36                  inst.init(*args, **kwds) 
37          finally: 
38              Cacheable._lock.release() 
39          return inst 
40   
41      @staticmethod 
42 -    def register(ob, key): 
43          if not ob.__class__ in Cacheable.registry: 
44              Cacheable.registry[ob.__class__] = {} 
45          if key in Cacheable.registry[ob.__class__]: 
46              ob = Cacheable.registry[ob.__class__][key] 
47              #print "already registered: %s" % repr(ob) 
48              return (ob, True) 
49          else: 
50              #print "not already registered: %s" % ob.__class__ 
51              Cacheable.registry[ob.__class__][key] = ob 
52              return (ob, False) 
53