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# Copyright 2015-2017 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 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_is_loaded = False
self._by_chunk_id_tree = None
self._by_checksum_tree = None
self._used_by_tree = None
def commit(self):
self._load_data()
self._save_data()
def _save_data(self):
root = {
'checksum_algorithm': self._checksum_name,
'by_chunk_id': self._by_chunk_id_tree.commit(),
'by_checksum': self._by_checksum_tree.commit(),
'used_by': self._used_by_tree.commit(),
}
blob = obnamlib.serialise_object(root)
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)
leaf_store = obnamlib.LeafStore()
leaf_store.set_blob_store(blob_store)
if blob is None:
self._by_chunk_id_tree = self._empty_cowtree(leaf_store)
self._by_checksum_tree = self._empty_cowtree(leaf_store)
self._used_by_tree = self._empty_cowtree(leaf_store)
else:
data = obnamlib.deserialise_object(blob)
self._checksum_name = data['checksum_algorithm']
self._by_chunk_id_tree = self._load_cowtree(
leaf_store, data['by_chunk_id'])
self._by_checksum_tree = self._load_cowtree(
leaf_store, data['by_checksum'])
self._used_by_tree = self._load_cowtree(
leaf_store, data['used_by'])
self._data_is_loaded = True
def _empty_cowtree(self, leaf_store):
cow = obnamlib.CowTree()
cow.set_leaf_store(leaf_store)
return cow
def _load_cowtree(self, leaf_store, list_id):
cow = self._empty_cowtree(leaf_store)
cow.set_list_node(list_id)
return cow
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()
client_ids = self._used_by_tree.lookup(chunk_id)
logging.debug(
'xxx before adding to used-by: chunk %r is used by %r',
chunk_id, client_ids)
self._by_chunk_id_tree.insert(chunk_id, token)
chunk_ids = self._by_checksum_tree.lookup(token)
if chunk_ids is None:
chunk_ids = [chunk_id]
elif chunk_id not in chunk_ids:
chunk_ids.append(chunk_id)
self._by_checksum_tree.insert(token, chunk_ids)
if client_ids is None:
client_ids = [client_id]
elif client_id not in client_ids:
client_ids.append(client_id)
self._used_by_tree.insert(chunk_id, client_ids)
logging.debug(
'xxx after adding to used-by: chunk %r is used by %r',
chunk_id, client_ids)
def find_chunk_ids_by_token(self, token):
self._load_data()
result = self._by_checksum_tree.lookup(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
client_ids = self._used_by_tree.lookup(chunk_id)
logging.debug(
'xxx before removing used_by: chunk %r is used by %r',
chunk_id, client_ids)
if client_ids is not None and client_id in client_ids:
client_ids.remove(client_id)
self._used_by_tree.insert(chunk_id, client_ids)
if client_ids:
still_used = True
else:
# We leave an empty list, and use that in
# remove_unused_chunks to indicate an unused chunk.
pass
logging.debug(
'xxx after removing used_by: chunk %r is used by %r',
chunk_id, client_ids)
return still_used
def _remove_chunk_by_id(self, chunk_id):
token = self._by_chunk_id_tree.lookup(chunk_id)
if token is not None:
self._by_chunk_id_tree.remove(chunk_id)
return token
def _remove_chunk_by_checksum(self, chunk_id, token):
chunk_ids = self._by_checksum_tree.lookup(token)
if chunk_ids is not None and chunk_id in chunk_ids:
chunk_ids.remove(chunk_id)
self._by_checksum_tree.insert(token, chunk_ids)
def _remove_all_used_by(self, chunk_id):
self._used_by_tree.insert(chunk_id, None)
def remove_unused_chunks(self, chunk_store):
unused_chunks = self.get_unused_chunks()
self.drop_unused_chunks(unused_chunks)
maybe_unused_bags = self.get_bags_containing_chunks(
chunk_store, unused_chunks)
for bag_id in maybe_unused_bags:
chunk_ids = chunk_store.get_chunks_in_bag(bag_id)
logging.debug(
'remove_unused_chunk: can bag %r be removed?', bag_id)
for chunk_id in chunk_ids:
logging.debug(
'remove_unused_chunk: chunk %r, used: %r',
chunk_id, self.is_chunk_used_by_anyone(chunk_id))
if not self.any_chunk_is_used_by_someone(chunk_ids):
logging.debug('remove_unused_chunk: remove bag %r', bag_id)
chunk_store.remove_bag(bag_id)
else:
logging.debug(
'remove_unused_chunk: bag %r cannot be removed', bag_id)
def get_unused_chunks(self):
return [
chunk_id
for chunk_id in self._used_by_tree.keys()
if not self.is_chunk_used_by_anyone(chunk_id)
]
def is_chunk_used_by_anyone(self, chunk_id):
return self._used_by_tree.lookup(chunk_id) not in (None, [])
def drop_unused_chunks(self, chunk_ids):
# By this time we know the chunk is only in the used_by tree.
for chunk_id in chunk_ids:
self._used_by_tree.remove(chunk_id)
def get_bags_containing_chunks(self, chunk_store, chunk_ids):
return set(
chunk_store.get_bag_id(chunk_id)
for chunk_id in chunk_ids
)
def any_chunk_is_used_by_someone(self, chunk_ids):
return any(
self.is_chunk_used_by_anyone(chunk_id)
for chunk_id in chunk_ids
)
def validate_chunk_content(self, chunk_id):
return None
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