Bug#703366: RFH: apt-file -- search for files within Debian packages (command-line interface)

[Stefan Fritsch <sf@sfritsch.de>]

On Wednesday 20 March 2013, Niels Thykier wrote:
> > I would like to take the opportunity to invite anyone interested
> > to join deity@lists.debian.org (cc'ed) and discuss if and how we
> > could work on integrating apt-file more closely with other apt-*
> > tools.
> >
> > 
> >
> > I (and I guess many other users) would be pleased if we could
> > reach a point in which "apt-get update" (or its countless
> > alternative ways) would update indeed all data I requested to be
> > downloaded as a user rather than remembering to run also
> > "apt-file update" (and "debtags update" and and and).
> >
> > 
> 
> Indeed that would be great.  Maybe packages like apt-file could
> install a file in some directory APT reads saying "Please download
> X with updates" ?

That would be the perfect solution. Unfortunately, it would also mean 
that apt's pdiff implementation would need to be rewritten because it 
is so inefficient. AFAICS, with N the number of lines in the Contents 
or Packages file, and M the number of diffs, apt currently scales like 
O(N*M) while apt-file's implementation scales more like O(M+N). Since 
the content files are much larger than the packages files, this would 
be an even bigger issue with apt-file than it is with apt. In order to 
get decent performance, one really must download all diffs and apply 
them at the same time. Also, it is not possible to keep the whole 
Contents file in memory (though I don't know if apt does that).

But of course, if someone would tackle that problem, the benefit would 
be much greater than only to apt-file. Maybe this would be a nice GSOC 
project? Don't know if it is too late for this year's deadline, 
though.