Re: ioctls for gnome-vfs

[Alexander Larsson <alexl redhat com>]

On 15 Nov 2002, Alex Graveley wrote:

> Hi,
> 
> On Fri, 2002-11-15 at 15:09, Joe Shaw wrote:
> > I'm not so sure.  Maybe it's just the terminology, but "metadata" to me
> > means any arbitrary information layered on top of files, probably
> > persistent.  Image thumbnailing seems like a good use of metadata to
> > me.  
> > 
> > This seems more like additional parameters on the method itself...
> > things like setting HTTP headers for a specific request or passive mode
> > on FTP.
> 
> I think it depends completely on the metadata being twiddled.  For
> instance: idealy we would want metadata stored on an mp3 and prefixed
> with "id3-tag:" to be stored in the id3 section of the file itself. 
> Just as likely is setting headers in an http transfer, before a read or
> write; in this case the meta-data should only be available for setting
> on an open file handle, and not on a URI.

Meta-data changes changing the actual file? Ick! That wouldn't be metadata 
at all, that would be data.
 
> Also an issue for me is the that i can't think of any good reason for a
> file-control api.  We don't expose sockets or file descriptors.  Ans the
> example that alexl posted is certainly metadata and not an ioctl, since
> the attribute is associated with a file and would presumably remain for
> its lifetime.

I'd love to have a real metadata API in gnome-vfs, but I don't think it 
can replace a real per-backend ioctl style operation. While for some 
designs of metadata you might be able to hack it into doing backend 
specific things that is really not what metadata is for.

Metadata is auxilliary information about the file, some metadata is 
already stored by the os, such as file modification dates, permissions 
etc. Others (as used by nautilus) are custom icon, icon position, icon 
stretch factor, etc.

-- 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
 Alexander Larsson                                            Red Hat, Inc 
                   alexl redhat com    alla lysator liu se 
He's an impetuous day-dreaming paramedic on the run. She's a beautiful 
renegade cab driver from a family of eight older brothers. They fight crime!