mirror of https://github.com/python/cpython
50 lines
1.5 KiB
Python
50 lines
1.5 KiB
Python
_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)
|