42 lines
1.3 KiB
Python
42 lines
1.3 KiB
Python
# Copyright: (c) 2018, Ansible Project
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# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
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from __future__ import (absolute_import, division, print_function)
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__metaclass__ = type
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"""
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This file contains common code for building ansible. If you want to use code from here at runtime,
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it needs to be moved out of this file and the implementation looked over to figure out whether API
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should be changed before being made public.
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"""
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import os.path
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def update_file_if_different(filename, b_data):
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'''
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Replace file content only if content is different.
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This preserves timestamps in case the file content has not changed. It performs multiple
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operations on the file so it is not atomic and may be slower than simply writing to the file.
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:arg filename: The filename to write to
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:b_data: Byte string containing the data to write to the file
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'''
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try:
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with open(filename, 'rb') as f:
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b_data_old = f.read()
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except IOError as e:
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if e.errno != 2:
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raise
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# File did not exist, set b_data_old to a sentinel value so that
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# b_data gets written to the filename
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b_data_old = None
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if b_data_old != b_data:
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with open(filename, 'wb') as f:
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f.write(b_data)
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return True
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return False
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