Current File : //proc/self/root/lib/python2.7/site-packages/salt/utils/gzip_util.py
# -*- coding: utf-8 -*-
'''
salt.utils.gzip
~~~~~~~~~~~~~~~
Helper module for handling gzip consistently between 2.7+ and 2.6-
'''
from __future__ import absolute_import, unicode_literals, print_function
# Import python libs
import gzip
# Import Salt libs
import salt.utils.files
# Import 3rd-party libs
from salt.ext import six
from salt.ext.six import BytesIO
class GzipFile(gzip.GzipFile):
def __init__(self, filename=None, mode=None,
compresslevel=9, fileobj=None):
gzip.GzipFile.__init__(self, filename, mode, compresslevel, fileobj)
### Context manager (stolen from Python 2.7)###
def __enter__(self):
"""Context management protocol. Returns self."""
return self
def __exit__(self, *args):
"""Context management protocol. Calls close()"""
self.close()
def open(filename, mode="rb", compresslevel=9):
if hasattr(gzip.GzipFile, '__enter__'):
return gzip.open(filename, mode, compresslevel)
else:
return GzipFile(filename, mode, compresslevel)
def open_fileobj(fileobj, mode='rb', compresslevel=9):
if hasattr(gzip.GzipFile, '__enter__'):
return gzip.GzipFile(
filename='', mode=mode, fileobj=fileobj,
compresslevel=compresslevel
)
return GzipFile(
filename='', mode=mode, fileobj=fileobj, compresslevel=compresslevel
)
def compress(data, compresslevel=9):
'''
Returns the data compressed at gzip level compression.
'''
buf = BytesIO()
with open_fileobj(buf, 'wb', compresslevel) as ogz:
if six.PY3 and not isinstance(data, bytes):
data = data.encode(__salt_system_encoding__)
ogz.write(data)
compressed = buf.getvalue()
return compressed
def uncompress(data):
buf = BytesIO(data)
with open_fileobj(buf, 'rb') as igz:
unc = igz.read()
return unc
def compress_file(fh_, compresslevel=9, chunk_size=1048576):
'''
Generator that reads chunk_size bytes at a time from a file/filehandle and
yields the compressed result of each read.
.. note::
Each chunk is compressed separately. They cannot be stitched together
to form a compressed file. This function is designed to break up a file
into compressed chunks for transport and decompression/reassembly on a
remote host.
'''
try:
bytes_read = int(chunk_size)
if bytes_read != chunk_size:
raise ValueError
except ValueError:
raise ValueError('chunk_size must be an integer')
try:
while bytes_read == chunk_size:
buf = BytesIO()
with open_fileobj(buf, 'wb', compresslevel) as ogz:
try:
bytes_read = ogz.write(fh_.read(chunk_size))
except AttributeError:
# Open the file and re-attempt the read
fh_ = salt.utils.files.fopen(fh_, 'rb')
bytes_read = ogz.write(fh_.read(chunk_size))
yield buf.getvalue()
finally:
try:
fh_.close()
except AttributeError:
pass
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