tiramisu/tiramisu/storage/util.py

# -*- coding: utf-8 -*-
"utils used by storage"
# Copyright (C) 2013-2017 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 Lesser General Public License as published by the
# Free Software Foundation, either version 3 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
# ____________________________________________________________
from ..setting import owners


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

    def __init__(self, storage):
        self._cache = {}
        self._storage = storage

    def setcache(self, path, val, time, index):
        """add val in cache for a specified path
        if slave, add index
        """
        self._cache.setdefault(path, {})[index] = (val, time)

    def getcache(self, path, exp, index):
        value, created = self._cache[path][index]
        if created is None or exp <= created:
            return True, value
        return False, None  # pragma: no cover

    def delcache(self, path):
        """remove cache for a specified path
        """
        if path in  self._cache:
            del self._cache[path]

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

        :param path: the path's option
        """
        return path in self._cache and index in self._cache[path]

    def reset_expired_cache(self, exp):
        cache_keys = list(self._cache.keys())
        for key in cache_keys:
            key_cache_keys = list(self._cache[key].keys())
            for index in key_cache_keys:
                val, created = self._cache[key][index]
                if created is not None and exp > created:
                    del(self._cache[key][index])
                    if self._cache[key] == {}:
                        del(self._cache[key])

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

    def get_cached(self, context):
        """return all values in a dictionary
        example: {'path1': {'index1': ('value1', 'time1')}, 'path2': {'index2': ('value2', 'time2', )}}
        """
        return self._cache