openmedialibrary/oml/cache.py
2016-02-26 17:14:56 +05:30

43 lines
1.1 KiB
Python

from threading import Lock
import time
class Cache(dict):
def __init__(self, ttl=10):
self._ttl = ttl
self._added = {}
self._lock = {}
def lock(self, key):
if key not in self._lock:
self._lock[key] = Lock()
self._lock[key].acquire()
def get(self, key):
now = time.time()
for k, value in list(self._added.items()):
if value < now:
self._added.pop(k, None)
self.pop(k, None)
self._lock.pop(k, None)
if key in self._lock:
self._lock[key].acquire()
return dict.get(self, key)
def set(self, key, value, ttl=None):
ttl = ttl or self._ttl
self._added[key] = time.time() + ttl
dict.__setitem__(self, key, value)
q = self._lock.pop(key, None)
if q:
q.release()
def delete(self, key):
if key in self._added:
del self._added[key]
del self[key]
def clear(self, prefix):
for key in list(self):
if key.startswith(prefix):
self.delete(key)