Source Code for Module buildbot.process.cache

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14  # Copyright Buildbot Team Members 
15   
16  from buildbot.util import lru 
17  from buildbot import config 
18  from twisted.application import service 
19   
20 -class CacheManager(config.ReconfigurableServiceMixin, service.Service): 
21      """ 
22      A manager for a collection of caches, each for different types of objects 
23      and with potentially-overlapping key spaces. 
24   
25      There is generally only one instance of this class, available at 
26      C{master.caches}. 
27      """ 
28   
29      # a cache of length one still has many benefits: it collects objects that 
30      # remain referenced elsewhere; it collapses simultaneous misses into one 
31      # miss function; and it will optimize repeated fetches of the same object. 
32      DEFAULT_CACHE_SIZE = 1 
33   
34 -    def __init__(self): 
35          self.setName('caches') 
36          self.config = {} 
37          self._caches = {} 
38   
39 -    def get_cache(self, cache_name, miss_fn): 
40          """ 
41          Get an L{AsyncLRUCache} object with the given name.  If such an object 
42          does not exist, it will be created.  Since the cache is permanent, this 
43          method can be called only once, e.g., in C{startService}, and it value 
44          stored indefinitely. 
45   
46          @param cache_name: name of the cache (usually the name of the type of 
47          object it stores) 
48          @param miss_fn: miss function for the cache; see L{AsyncLRUCache} 
49          constructor. 
50          @returns: L{AsyncLRUCache} instance 
51          """ 
52          try: 
53              return self._caches[cache_name] 
54          except KeyError: 
55              max_size = self.config.get(cache_name, self.DEFAULT_CACHE_SIZE) 
56              assert max_size >= 1 
57              c = self._caches[cache_name] = lru.AsyncLRUCache(miss_fn, max_size) 
58              return c 
59   
60 -    def reconfigService(self, new_config): 
61          self.config = new_config.caches 
62          for name, cache in self._caches.iteritems(): 
63              cache.set_max_size(new_config.caches.get(name, 
64                                                  self.DEFAULT_CACHE_SIZE)) 
65   
66          return config.ReconfigurableServiceMixin.reconfigService(self, 
67                                                              new_config) 
68   
69 -    def get_metrics(self): 
70          return dict([ 
71              (n, dict(hits=c.hits, refhits=c.refhits, 
72                       misses=c.misses, max_size=c.max_size)) 
73              for n, c in self._caches.iteritems()]) 
74