Save critical files not directly, but via temp file

src/mmdiary/utils/jsoncache.py

@@ -26,8 +26,10 @@ def __load(self):
     def __save(self):
         if self.__filename is None or not self.__changed:
             return
-        with open(self.__filename, "wb") as f:
+        tmpfile = self.__filename + ".tmp"
+        with open(tmpfile, "wb") as f:
             pickle.dump(self.__data, f)
+        os.replace(tmpfile, self.__filename)
 
     def __load_json(self, filename):
         with open(filename, "r", encoding="utf-8") as f:

src/mmdiary/video/uploader/dailymotion.py

@@ -51,9 +51,11 @@ def __read(self):
                     self.__current = current
 
     def __save(self):
-        with open(self.__accounts_file, "w", encoding="utf-8") as f:
+        tmpfile = self.__accounts_file + ".tmp"
+        with open(tmpfile, "w", encoding="utf-8") as f:
             data = {"accounts": self.__accounts, "current": self.__current}
             json.dump(data, f, ensure_ascii=False, indent=2)
+        os.replace(tmpfile, self.__accounts_file)
 
     def get_all(self):
         return self.__accounts