_orig_open = open | |
class _BkFile: | |
def __init__(self, file, mode, bufsize): | |
import os | |
self.__filename = file | |
self.__backup = file + '~' | |
try: | |
os.unlink(self.__backup) | |
except os.error: | |
pass | |
try: | |
os.rename(file, self.__backup) | |
except os.error: | |
self.__backup = None | |
self.__file = _orig_open(file, mode, bufsize) | |
self.closed = self.__file.closed | |
self.fileno = self.__file.fileno | |
self.flush = self.__file.flush | |
self.isatty = self.__file.isatty | |
self.mode = self.__file.mode | |
self.name = self.__file.name | |
self.read = self.__file.read | |
self.readinto = self.__file.readinto | |
self.readline = self.__file.readline | |
self.readlines = self.__file.readlines | |
self.seek = self.__file.seek | |
self.softspace = self.__file.softspace | |
self.tell = self.__file.tell | |
self.truncate = self.__file.truncate | |
self.write = self.__file.write | |
self.writelines = self.__file.writelines | |
def close(self): | |
self.__file.close() | |
if self.__backup is None: | |
return | |
import filecmp | |
if filecmp.cmp(self.__backup, self.__filename, shallow = 0): | |
import os | |
os.unlink(self.__filename) | |
os.rename(self.__backup, self.__filename) | |
def open(file, mode = 'r', bufsize = -1): | |
if 'w' not in mode: | |
return _orig_open(file, mode, bufsize) | |
return _BkFile(file, mode, bufsize) |