mirror of https://github.com/python/cpython
51 lines
1.4 KiB
Python
51 lines
1.4 KiB
Python
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_orig_open = open
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class _BkFile:
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def __init__(self, file, mode, bufsize):
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import os
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self.__filename = file
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self.__backup = file + '~'
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try:
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os.unlink(self.__backup)
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except os.error:
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pass
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try:
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os.rename(file, self.__backup)
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except os.error:
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self.__backup = None
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self.__file = _orig_open(file, mode, bufsize)
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self.closed = self.__file.closed
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self.fileno = self.__file.fileno
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self.flush = self.__file.flush
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self.isatty = self.__file.isatty
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self.mode = self.__file.mode
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self.name = self.__file.name
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self.read = self.__file.read
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self.readinto = self.__file.readinto
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self.readline = self.__file.readline
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self.readlines = self.__file.readlines
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self.seek = self.__file.seek
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self.softspace = self.__file.softspace
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self.tell = self.__file.tell
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self.truncate = self.__file.truncate
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self.write = self.__file.write
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self.writelines = self.__file.writelines
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def close(self):
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self.__file.close()
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if self.__backup is None:
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return
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import cmp
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# don't use cmp.cmp because of NFS bugs :-( and
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# anyway, the stat mtime values differ so do_cmp will
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# most likely be called anyway
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if cmp.do_cmp(self.__backup, self.__filename):
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import os
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os.unlink(self.__filename)
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os.rename(self.__backup, self.__filename)
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def open(file, mode = 'r', bufsize = -1):
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if 'w' not in mode:
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return _orig_open(file, mode, bufsize)
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return _BkFile(file, mode, bufsize)
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