Hi,

The attached patch implements the feature of controlling the display
length of filename in dired buffers.

When setting this option to `window', the long filename is shortened
by hiding the middle part to ensure that the whole line needs not to
be wrapped. The option can also be set to an integer, meaning the
maximum display length of filename. For users who turn on line
truncation, this feature can display the end part including the file
extension, which I think is convenient.


Best,

--
Liu Hui