[pacman-dev] some more delta stats

[Xavier]

On Fri, Mar 6, 2009 at 3:38 PM, Nagy Gabor <ngaba at bibl.u-szeged.hu> wrote:
> Well, these results are cool. If deltas finally work perfectly in alpm we
> may want to factorize (move) it to a stand-alone xdelta client-server(?)
> stuff, which is something similar to rsync (but we need a vcs-like stuff
> here). Well, I know this idea is very ambitious, but I have the impression
> that we (== Nathan and Xavier:) did something, from which the whole open
> source community could profit. (Moreover, our alpm code would be cleaner :)
> At least I didn't find anything which is similar to our low-bandwidth
> delta-based "vcs system" on the net.

There would be a huge drawback with this idea, that we couldn't simply
re-use all the existing http/ftp mirrors.

However, I considered writing standalone apps in python :

1) delta-add.py : analog of repo-add but for delta.
delta-add delta-database foo1.delta foo2.delta ...

2) delta-download.py :
have a delta.conf file, analog to pacman.conf, to specify delta mirrors
delta-download url : either use deltas from the delta mirrors to
generate the wanted package, or download the url directly

I was motivated by this solution, when I realized that the repository
system implemented by pacman is quite nice :
* pacman.conf specifying for each repo multiple possible urls (mirroring system)
* refresh only when needed using .lastupdate

So that I would have to reimplement / duplicate this system.
Also by moving this to an external app, it means the refreshing of the
database has to be made for each download (for each download, the
external client app has to be called).

So I lost my motivation and this project didn't go far.