Early termination when filename is too long

[sorairolake]

The maximum filename length is 240 bytes on Commons.

There is a hard limit on filenames of 240 bytes long.

https://commons.wikimedia.org/wiki/Commons:File_naming#Clear

Japanese typically uses 3 bytes to represent a single character when encoded in UTF-8. This is about 80 characters. This also applies to Chinese and Korean.

Sometimes, the filename length limit is reached in these languages, so I think it is better to check the filename length before processing.