tiramisu/tiramisu/storage/dictionary/storage.py

# -*- coding: utf-8 -*-
"default plugin for cache: set it in a simple dictionary"
# Copyright (C) 2013 Team tiramisu (see AUTHORS for all contributors)
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# ____________________________________________________________


from tiramisu.i18n import _
from tiramisu.error import ConfigError


def enumerate():
    return []


def delete(session_id):
    raise ConfigError(_('dictionary storage cannot delete session'))


class Storage(object):
    __slots__ = tuple()
    storage = 'dictionary'

    def __init__(self, session_id, is_persistent):
        if is_persistent:
            raise ValueError(_('a dictionary cannot be persistent'))


class Cache(object):
    __slots__ = ('_cache',)
    key_is_path = False

    def __init__(self):
        self._cache = {}

    def setcache(self, cache_type, path, val, time):
        self._cache[path] = (val, time)

    def getcache(self, cache_type, path, exp):
        value, created = self._cache[path]
        if exp < created:
            return True, value
        return False, None

    def hascache(self, cache_type, path):
        """ path is in the cache

        :param cache_type: value | property
        :param path: the path's option
        """
        return path in self._cache

    def reset_expired_cache(self, cache_type, exp):
        keys = self._cache.keys()
        for key in keys:
            val, created = self._cache[key]
            if exp > created:
                del(self._cache[key])

    def reset_all_cache(self, cache_type):
        "empty the cache"
        self._cache.clear()

    def get_cached(self, cache_type, context):
        """return all values in a dictionary
        example: {'path1': ('value1', 'time1'), 'path2': ('value2', 'time2')}
        """
        return self._cache