| _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 |
| try: |
| self.readinto = self.__file.readinto |
| except AttributeError: |
| pass |
| self.readline = self.__file.readline |
| self.readlines = self.__file.readlines |
| self.seek = self.__file.seek |
| 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) |