Radicale/radicale/storage/multifilesystem/history.py
2023-02-10 22:03:33 +01:00

95 lines
4.2 KiB
Python

# This file is part of Radicale - CalDAV and CardDAV server
# Copyright © 2014 Jean-Marc Martins
# Copyright © 2012-2017 Guillaume Ayoub
# Copyright © 2017-2019 Unrud <unrud@outlook.com>
#
# This library 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 3 of the License, or
# (at your option) any later version.
#
# This library 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 Radicale. If not, see <http://www.gnu.org/licenses/>.
import binascii
import contextlib
import os
import pickle
from typing import BinaryIO, Optional, cast
import radicale.item as radicale_item
from radicale import pathutils
from radicale.log import logger
from radicale.storage import multifilesystem
from radicale.storage.multifilesystem.base import CollectionBase
class CollectionPartHistory(CollectionBase):
_max_sync_token_age: int
def __init__(self, storage_: "multifilesystem.Storage", path: str,
filesystem_path: Optional[str] = None) -> None:
super().__init__(storage_, path, filesystem_path)
self._max_sync_token_age = storage_.configuration.get(
"storage", "max_sync_token_age")
def _update_history_etag(self, href, item):
"""Updates and retrieves the history etag from the history cache.
The history cache contains a file for each current and deleted item
of the collection. These files contain the etag of the item (empty
string for deleted items) and a history etag, which is a hash over
the previous history etag and the etag separated by "/".
"""
history_folder = os.path.join(self._filesystem_path,
".Radicale.cache", "history")
try:
with open(os.path.join(history_folder, href), "rb") as f:
cache_etag, history_etag = pickle.load(f)
except (FileNotFoundError, pickle.UnpicklingError, ValueError) as e:
if isinstance(e, (pickle.UnpicklingError, ValueError)):
logger.warning(
"Failed to load history cache entry %r in %r: %s",
href, self.path, e, exc_info=True)
cache_etag = ""
# Initialize with random data to prevent collisions with cleaned
# expired items.
history_etag = binascii.hexlify(os.urandom(16)).decode("ascii")
etag = item.etag if item else ""
if etag != cache_etag:
self._storage._makedirs_synced(history_folder)
history_etag = radicale_item.get_etag(
history_etag + "/" + etag).strip("\"")
# Race: Other processes might have created and locked the file.
with contextlib.suppress(PermissionError), self._atomic_write(
os.path.join(history_folder, href), "wb") as fo:
fb = cast(BinaryIO, fo)
pickle.dump([etag, history_etag], fb)
return history_etag
def _get_deleted_history_hrefs(self):
"""Returns the hrefs of all deleted items that are still in the
history cache."""
history_folder = os.path.join(self._filesystem_path,
".Radicale.cache", "history")
with contextlib.suppress(FileNotFoundError):
for entry in os.scandir(history_folder):
href = entry.name
if not pathutils.is_safe_filesystem_path_component(href):
continue
if os.path.isfile(os.path.join(self._filesystem_path, href)):
continue
yield href
def _clean_history(self):
# Delete all expired history entries of deleted items.
history_folder = os.path.join(self._filesystem_path,
".Radicale.cache", "history")
self._clean_cache(history_folder, self._get_deleted_history_hrefs(),
max_age=self._max_sync_token_age)