def __init__(self, get_function=None):
self.data = None
self.get_function = get_function
from qon.observe import Dependencies
self.__depends = Dependencies()
self.__disable_cache = False
def upgradeToVersion1(self):
from qon.observe import Dependencies
self.__depends = Dependencies()
self.version_upgrade_done()
class PersistentCache(QonPersistent):
"""Generic Persistent caching mechanism."""
persistenceVersion = 2
def __init__(self, get_function=None):
self.data = None
self.get_function = get_function
from qon.observe import Dependencies
self.__depends = Dependencies()
self.__disable_cache = False
def upgradeToVersion1(self):
from qon.observe import Dependencies
self.__depends = Dependencies()
self.version_upgrade_done()
# alex added __disable_cache ability so that directives like on-user-link can
# call disable_cache to signify that the cache is not to be used
def upgradeToVersion2(self):
self.__disable_cache = False
self.version_upgrade_done()
def set(self, data):
self.data = data
def get(self):
from quixote.html import htmltext
# check dependencies and cache setting
if (not self.__depends.up_to_date()) or self.__disable_cache or self.__depends.any_caches_disabled():
self.data = None
if self.data:
return self.data
if self.get_function:
# assume that we'll be able to use the cache
self.__disable_cache = False
self.__depends.remove_all_dependencies()
self.data = self.get_function()
# can't pickle htmltext objects
if type(self.data) is htmltext:
self.data = str(self.data)
return self.data
def flush(self):
"""Flush cache. E.g. when something it depends on has changed."""
self.data = None
self.__depends.remove_all_dependencies()
def add_dependency(self, target):
self.__depends.add_dependency(target)
def disable_cache(self):
self.__disable_cache = True
def cache_disabled(self):
return self.__disable_cache