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# groupcompress, a bzr plugin providing new compression logic.
# Copyright (C) 2008 Canonical Limited.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as published
# by the Free Software Foundation.
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
"""Core compression logic for compressing streams of related files."""
from bzrlib import pack
from bzrlib.knit import _DirectPackAccess
from bzrlib.plugins.index2.repofmt import InMemoryBTree
from bzrlib.versionedfile import VersionedFiles
def make_pack_factory(graph, delta, keylength):
"""Create a factory for creating a pack based groupcompress.
This is only functional enough to run interface tests, it doesn't try to
provide a full pack environment.
:param graph: Store a graph.
:param delta: Delta compress contents.
:param keylength: How long should keys be.
"""
def factory(transport):
parents = graph or delta
ref_length = 0
if graph:
ref_length += 1
if delta:
ref_length += 1
max_delta_chain = 200
else:
max_delta_chain = 0
graph_index = InMemoryBTree(reference_lists=ref_length,
key_elements=keylength)
stream = transport.open_write_stream('newpack')
writer = pack.ContainerWriter(stream.write)
writer.begin()
index = _GCGraphIndex(graph_index, lambda:True, parents=parents,
deltas=delta, add_callback=graph_index.add_nodes)
access = _DirectPackAccess({})
access.set_writer(writer, graph_index, (transport, 'newpack'))
result = GroupCompressVersionedFiles(index, access,
max_delta_chain=max_delta_chain)
result.stream = stream
result.writer = writer
return result
return factory
def cleanup_pack_group(versioned_files):
versioned_files.stream.close()
versioned_files.writer.end()
class GroupCompressVersionedFiles(VersionedFiles):
"""A group-compress based VersionedFiles implementation."""
def __init__(self, index, access, max_delta_chain=-1):
"""Create a GroupCompressVersionedFiles object.
:param index: The index object storing access and graph data.
:param access: The access object storing raw data.
"""
class _GCGraphIndex(object):
"""Mapper from GroupCompressVersionedFiles needs into GraphIndex storage."""
def __init__(self, graph_index, is_locked, deltas=False, parents=True,
add_callback=None):
"""Construct a _GCGraphIndex on a graph_index.
:param graph_index: An implementation of bzrlib.index.GraphIndex.
:param is_locked: A callback to check whether the object should answer
queries.
:param deltas: Allow delta-compressed records.
:param parents: If True, record knits parents, if not do not record
parents.
:param add_callback: If not None, allow additions to the index and call
this callback with a list of added GraphIndex nodes:
[(node, value, node_refs), ...]
:param is_locked: A callback, returns True if the index is locked and
thus usable.
"""
self._add_callback = add_callback
self._graph_index = graph_index
self._deltas = deltas
self._parents = parents
if deltas and not parents:
# XXX: TODO: Delta tree and parent graph should be conceptually
# separate.
raise KnitCorrupt(self, "Cannot do delta compression without "
"parent tracking.")
self.has_graph = parents
self._is_locked = is_locked
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