Re: normalizing filenames and strings

[Alexander Larsson <alexl redhat com>]

On Tue, 2007-03-27 at 13:15 -0400, Dr. Michael J. Chudobiak wrote:
> > Filenames could also be NFC normalized when created, although that's
> > not absolutely necessary.
> 
> It would be nice if gnome mandated a standard approach for 
> normalization. Does everyone like NFC? (http://unicode.org/reports/tr15 
> for info.)
> 
> > This could be fixed at a low level, in gtk filechooser for some cases
> > or in apps. Gnome-vfs should handle that too.
> 
> It would be nice if gnome-vfs could handle this in the background, so 
> coders don't have to worry about uri escaping and normalization at the 
> same time. (The existing normalization functions have to be used on 
> unescaped URIs. It's already tricky enough keeping track of gnome-vfs 
> escaping issues...)

Its very hard and quite expensive to handle normalization automatically
at the low level. You have to intercept every i/o operation, and it can
introduce very strange behaviour (since we can't control whats already
on the disk). We have to accept that unix filenames are strings of bytes
and that we just cannot enforce any meaning on them (although we can do
our best to try to make them some normalized form of utf8).

For uri escaping I'm doing my best to make it not an issue in the new
GVFS API that is to replace gnome-vfs. (By not using uris much in the
API.)

In practice i don't think there is an enourmous problem. Most files are
either selected in the fileselector/filemanager (so we don't care about
normalization, just the filename bytestring that was selected) or for
new files, typed into the file selector.If the fileselector can do some
normalization for typed-in names we shouldn't really in normal use cause
any "duplicate" unnormalized filenames.

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
 Alexander Larsson                                            Red Hat, Inc 
                   alexl redhat com    alla lysator liu se 
He's a fiendish Republican photographer trapped in a world he never made. 
She's a strong-willed junkie Valkyrie with the power to see death. They fight 
crime!