[Culprit-Finder] Seperate gae related part in cache_decorator and gitile repository to gae_libs/

appengine/findit/util_scripts/local_cache.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import logging
 import os
 import pickle
 import threading
 import zlib
 
-from lib.cache_decorator import Cacher
+from lib.cache import Cache
 
 CACHE_DIR = os.path.join(os.path.expanduser('~'), '.predator', 'cache')
 
 
-class LocalCacher(Cacher):
+class LocalCache(Cache):
   """Cacher that uses local files to cache data."""
   lock = threading.Lock()
 
   def __init__(self, cache_dir=CACHE_DIR):
     self.cache_dir = cache_dir
-    with LocalCacher.lock:
-      if not os.path.exists(cache_dir): # pragma: no cover.
-        os.makedirs(cache_dir)
+    try:  # pragma: no cover.
+      os.makedirs(cache_dir)
+    except Exception:
+      pass
 
   def Get(self, key):
-    with LocalCacher.lock:
+    with LocalCache.lock:
       path = os.path.join(self.cache_dir, key)
       if not os.path.exists(path):
         return None
 
       try:
         with open(path) as f:
           return pickle.loads(zlib.decompress(f.read()))
       except Exception as error:  # pragma: no cover.
         raise Exception('Failed loading cache: %s' % error)
 
   def Set(self, key, data, expire_time=0):  # pylint: disable=W
-    with LocalCacher.lock:
+    with LocalCache.lock:
       try:
         with open(os.path.join(self.cache_dir, key), 'wb') as f:
           f.write(zlib.compress(pickle.dumps(data)))
       except Exception as e:  # pragma: no cover.
         raise Exception('Failed setting cache for key %s: %s' % (key, e))