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# -*- coding: utf-8 -*-
# Copyright © 2012-2020 Roberto Alsina and others.
# Permission is hereby granted, free of charge, to any
# person obtaining a copy of this software and associated
# documentation files (the "Software"), to deal in the
# Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the
# Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice
# shall be included in all copies or substantial portions of
# the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
# PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
# OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""Persistent state implementation."""
import json
import os
import shutil
import tempfile
import threading
from . import utils
class Persistor():
"""Persist stuff in a place.
This is an intentionally dumb implementation. It is *not* meant to be
fast, or useful for arbitrarily large data. Use lightly.
Intentionally it has no namespaces, sections, etc. Use as a
responsible adult.
"""
def __init__(self, path):
"""Where do you want it persisted."""
self._path = path
self._local = threading.local()
self._local.data = {}
def _set_site(self, site):
"""Set site and create path directory."""
self._site = site
utils.makedirs(os.path.dirname(self._path))
def get(self, key):
"""Get data stored in key."""
self._read()
return self._local.data.get(key)
def set(self, key, value):
"""Store value in key."""
self._read()
self._local.data[key] = value
self._save()
def delete(self, key):
"""Delete key and the value it contains."""
self._read()
if key in self._local.data:
self._local.data.pop(key)
self._save()
def _read(self):
if os.path.isfile(self._path):
with open(self._path) as inf:
self._local.data = json.load(inf)
def _save(self):
dname = os.path.dirname(self._path)
with tempfile.NamedTemporaryFile(dir=dname, delete=False, mode='w+', encoding='utf-8') as outf:
tname = outf.name
json.dump(self._local.data, outf, sort_keys=True, indent=2)
shutil.move(tname, self._path)
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