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# Copyright (C) 2011-2015 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 zlib
import obnamlib
class DeflateCompressionFilter(object):
def __init__(self, app):
self.tag = "deflate"
self.app = app
self.warned = False
def filter_read(self, data, repo, toplevel):
return zlib.decompress(data)
def filter_write(self, data, repo, toplevel):
how = self.app.settings['compress-with']
compressed = None
if how == 'deflate':
compressed = zlib.compress(data)
elif how == 'gzip':
if not self.warned:
self.app.ts.notify("--compress-with=gzip is deprecated. " +
"Use --compress-with=deflate instead")
self.warned = True
compressed = zlib.compress(data)
# If the compression result, the tag and the separator byte taken
# together are longer than the uncompressed input, let's store the
# uncompressed data to avoid waste upon transfer, storage and read.
if compressed and len(compressed) + len(self.tag) + 1 < len(data):
return compressed
return data
class CompressionPlugin(obnamlib.ObnamPlugin):
def enable(self):
self.app.settings.choice(
['compress-with'],
['none', 'deflate', 'gzip'],
'use PROGRAM to compress repository with '
'(one of none, deflate)',
metavar='PROGRAM')
hooks = [
('repository-data', DeflateCompressionFilter(self.app),
obnamlib.Hook.EARLY_PRIORITY),
]
for name, callback, prio in hooks:
self.app.hooks.add_callback(name, callback, prio)
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