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# Copyright 2015-2016 Lars Wirzenius
#
# 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 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# =*= License: GPL-3+ =*=
import errno
import logging
import os
import obnamlib
class GAChunkIndexes(object):
_well_known_blob = 'root'
def __init__(self):
self._fs = None
self._checksum_name = None
self.set_dirname('chunk-indexes')
self.clear()
def set_fs(self, fs):
self._fs = fs
# Load the data so that we can get the in-use checksum
# algorithm at once, before we use the default, just in case
# they're different.
self._load_data()
def set_default_checksum_algorithm(self, name):
if self._checksum_name is None:
self._checksum_name = name
def set_dirname(self, dirname):
self._dirname = dirname
def get_dirname(self):
return self._dirname
def clear(self):
self._data = {}
self._data_is_loaded = False
def commit(self):
self._load_data()
self._save_data()
def _save_data(self):
blob = obnamlib.serialise_object(self._data)
bag_store = obnamlib.BagStore()
bag_store.set_location(self._fs, self.get_dirname())
blob_store = obnamlib.BlobStore()
blob_store.set_bag_store(bag_store)
blob_store.put_well_known_blob(self._well_known_blob, blob)
def _load_data(self):
if not self._data_is_loaded:
bag_store = obnamlib.BagStore()
bag_store.set_location(self._fs, self.get_dirname())
blob_store = obnamlib.BlobStore()
blob_store.set_bag_store(bag_store)
blob = blob_store.get_well_known_blob(self._well_known_blob)
if blob is None:
self._data = {
'by_chunk_id': {
},
'by_checksum': {
self._checksum_name: {},
},
'used_by': {
},
}
else:
self._data = obnamlib.deserialise_object(blob)
assert self._data is not None
keys = self._data['by_checksum'].keys()
assert len(keys) == 1
self._checksum_name = keys[0]
self._data_is_loaded = True
def _get_filename(self):
return os.path.join(self.get_dirname(), 'data.dat')
def prepare_chunk_for_indexes(self, chunk_content):
summer = obnamlib.get_checksum_algorithm(self._checksum_name)
summer.update(chunk_content)
return summer.hexdigest()
def put_chunk_into_indexes(self, chunk_id, token, client_id):
self._load_data()
by_chunk_id = self._data['by_chunk_id']
by_chunk_id[chunk_id] = token
by_checksum = self._data['by_checksum'][self._checksum_name]
chunk_ids = by_checksum.get(token, [])
if chunk_id not in chunk_ids:
chunk_ids.append(chunk_id)
by_checksum[token] = chunk_ids
used_by = self._data['used_by']
client_ids = used_by.get(chunk_id, [])
if client_id not in client_ids:
client_ids.append(client_id)
used_by[chunk_id] = client_ids
def find_chunk_ids_by_token(self, token):
self._load_data()
by_checksum = self._data['by_checksum'][self._checksum_name]
result = by_checksum.get(token, [])
if not result:
raise obnamlib.RepositoryChunkContentNotInIndexes()
return result
def remove_chunk_from_indexes(self, chunk_id, client_id):
self._load_data()
if not self._remove_used_by(chunk_id, client_id):
token = self._remove_chunk_by_id(chunk_id)
self._remove_chunk_by_checksum(chunk_id, token)
def remove_chunk_from_indexes_for_all_clients(self, chunk_id):
self._load_data()
token = self._remove_chunk_by_id(chunk_id)
self._remove_chunk_by_checksum(chunk_id, token)
self._remove_all_used_by(chunk_id)
def _remove_used_by(self, chunk_id, client_id):
still_used = False
used_by = self._data['used_by']
client_ids = used_by.get(chunk_id, [])
if client_id in client_ids:
client_ids.remove(client_id)
if client_ids:
still_used = True
else:
# We leave an empty here, and use that in
# remove_unused_chunks to indicate an unused chunk.
pass
return still_used
def _remove_chunk_by_id(self, chunk_id):
by_chunk_id = self._data['by_chunk_id']
token = by_chunk_id.get(chunk_id, None)
if token is not None:
del by_chunk_id[chunk_id]
return token
def _remove_chunk_by_checksum(self, chunk_id, token):
by_checksum = self._data['by_checksum'][self._checksum_name]
chunk_ids = by_checksum.get(token, [])
if chunk_id in chunk_ids:
chunk_ids.remove(chunk_id)
if not chunk_ids:
del by_checksum[token]
def _remove_all_used_by(self, chunk_id):
used_by = self._data['used_by']
if chunk_id in used_by:
del used_by[chunk_id]
def remove_unused_chunks(self, chunk_store):
def find_ids_of_unused_chunks(used_by):
return set(x for x in used_by if not used_by[x])
def remove_from_used_by(used_by, chunk_ids):
for chunk_id in chunk_ids:
del used_by[chunk_id]
def get_bag_ids(chunk_ids):
return set(
obnamlib.parse_object_id(chunk_id)[0]
for chunk_id in chunks_to_remove)
def get_chunk_ids_in_bag(bag_id):
bag = chunk_store._bag_store.get_bag(bag_id)
return [
obnamlib.make_object_id(bag_id, i)
for i in range(len(bag))
]
def remove_bag_if_unused(used_by, bag_id):
chunk_ids = get_chunk_ids_in_bag(bag_id)
if not any(chunk_id in used_by for chunk_id in chunk_ids):
chunk_store._bag_store.remove_bag(bag_id)
self._load_data()
used_by = self._data['used_by']
chunks_to_remove = find_ids_of_unused_chunks(used_by)
remove_from_used_by(used_by, chunks_to_remove)
for bag_id in get_bag_ids(chunks_to_remove):
try:
remove_bag_if_unused(used_by, bag_id)
except EnvironmentError as e:
if e.errno == errno.ENOENT:
# The bag's missing. We log, but otherwise
# ignore that. Don't want to crash a forget
# operation just because a chunk that was
# meant to be removed is already removed.
logging.warning(
'Tried to delete bag that was missing: %s', bag_id)
else:
raise
def validate_chunk_content(self, chunk_id):
return None
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