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# Copyright 2010-2014 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/>.
import hashlib
import struct
import random
import tracing
import obnamlib
class ChunkList(obnamlib.RepositoryTree):
'''Repository's list of chunks.
The list maps a chunk id to its checksum.
The list is implemented as a B-tree, with the 64-bit chunk id as the
key, and the checksum as the value.
'''
def __init__(self, fs, node_size, upload_queue_size, lru_size, hooks):
tracing.trace('new ChunkList')
self.fmt = '!Q'
self.key_bytes = struct.calcsize(self.fmt)
obnamlib.RepositoryTree.__init__(self, fs, 'chunklist', self.key_bytes,
node_size, upload_queue_size,
lru_size, hooks)
self.keep_just_one_tree = True
def key(self, chunk_id):
return struct.pack(self.fmt, chunk_id)
def add(self, chunk_id, checksum):
tracing.trace('chunk_id=%s', chunk_id)
tracing.trace('checksum=%s', repr(checksum))
self.start_changes()
self.tree.insert(self.key(chunk_id), checksum)
def get_checksum(self, chunk_id):
if self.init_forest() and self.forest.trees:
t = self.forest.trees[-1]
return t.lookup(self.key(chunk_id))
raise KeyError(chunk_id)
def remove(self, chunk_id):
tracing.trace('chunk_id=%s', chunk_id)
self.start_changes()
key = self.key(chunk_id)
self.tree.remove_range(key, key)
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