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# BSD Licensed, Copyright (c) 2006-2010 TileCache Contributors
import os, sys, time
from warnings import warn
class Cache (object):
def __init__ (self, timeout = 30.0, stale_interval = 300.0, readonly = False, expire = False, sendfile = False, **kwargs):
self.stale = float(stale_interval)
self.timeout = float(timeout)
self.readonly = readonly
self.expire = expire
self.sendfile = sendfile and sendfile.lower() in ["yes", "y", "t", "true"]
if expire != False:
self.expire = long(expire)
def lock (self, tile, blocking = True):
start_time = time.time()
result = self.attemptLock(tile)
if result:
return True
elif not blocking:
return False
while result is not True:
if time.time() - start_time > self.timeout:
raise Exception("You appear to have a stuck lock. You may wish to remove the lock named:\n%s" % self.getLockName(tile))
time.sleep(0.25)
result = self.attemptLock(tile)
return True
def getLockName (self, tile):
return self.getKey(tile) + ".lck"
def getKey (self, tile):
raise NotImplementedError()
def attemptLock (self, tile):
raise NotImplementedError()
def unlock (self, tile):
raise NotImplementedError()
def get (self, tile):
raise NotImplementedError()
def set (self, tile, data):
raise NotImplementedError()
def delete(self, tile):
raise NotImplementedError()
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