111 lines
3.2 KiB
Python
111 lines
3.2 KiB
Python
# (C) Copyright 2016 Mirantis, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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GZIP = 'zlib'
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BZIP2 = 'bz2'
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XZ = 'lzma'
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COMPRESS_METHOD = 'compress'
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DECOMPRESS_METHOD = 'decompress'
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def get_compression_algo(compression_algo):
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algo = {
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'gzip': GZIP,
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'bzip2': BZIP2,
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'xz': XZ,
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}
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return algo.get(compression_algo)
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def one_shot_compress(compression_algo, data):
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compression_module = __import__(get_compression_algo(compression_algo))
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return getattr(compression_module, COMPRESS_METHOD)(data)
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def one_shot_decompress(compression_algo, data):
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compression_module = __import__(get_compression_algo(compression_algo))
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return getattr(compression_module, DECOMPRESS_METHOD)(data)
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class BaseCompressor(object):
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"""
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Base class for compress/decompress activities.
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"""
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def __init__(self, compression_algo):
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# TODO(raliev): lzma module exists in stdlib since Py3 only
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if compression_algo == 'xz':
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raise NotImplementedError('XZ compression not implemented yet')
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self.algo = get_compression_algo(compression_algo)
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self.module = __import__(self.algo)
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class Compressor(BaseCompressor):
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"""
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Compress chucks of data.
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"""
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MAX_COMPRESS_LEVEL = 9
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def __init__(self, compression_algo):
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super(Compressor, self).__init__(compression_algo)
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self.compressobj = self.create_compressobj(compression_algo)
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def create_compressobj(self, compression_algo):
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def get_obj_name():
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names = {
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'gzip': 'compressobj',
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'bzip2': 'BZ2Compressor',
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'xz': 'compressobj',
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}
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return names.get(compression_algo)
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obj_name = get_obj_name()
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return getattr(self.module, obj_name)(self.MAX_COMPRESS_LEVEL)
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def compress(self, data):
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return self.compressobj.compress(data)
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def flush(self):
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return self.compressobj.flush()
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class Decompressor(BaseCompressor):
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"""
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Decompress chucks of data.
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"""
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def __init__(self, compression_algo):
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super(Decompressor, self).__init__(compression_algo)
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self.decompressobj = self.create_decompressobj(compression_algo)
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def create_decompressobj(self, compression_algo):
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def get_obj_name():
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names = {
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'gzip': 'decompressobj',
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'bzip2': 'BZ2Decompressor',
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'xz': 'decompressobj',
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}
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return names.get(compression_algo)
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obj_name = get_obj_name()
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return getattr(self.module, obj_name)()
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def decompress(self, data):
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return self.decompressobj.decompress(data)
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def flush(self):
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return self.decompressobj.flush()
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