Re: [PATCH 1/4] gitweb: notes feature

[Johan Herland <johan@herland.net>]

On Sunday 07 February 2010, Jakub Narebski wrote:
> On Sat, 6 Feb 2010, Giuseppe Bilotta wrote:
> > On the other hand, as mentioned by Junio, this approach is not
> > future-proof enough for any kind of fan-out schemes.
> 
> On the third hand ;-P you propose below a trick to deal with fan-out
> schemes, assuming that they use 2-character component breaking.

The current notes code (as it stands in 'pu') use only 2-character component 
breaking, and I don't see any other fanout mechanism being added anytime 
soon.

> Also, perhaps "git notes show" should acquire --batch / --batch-check
> options, similar to git-cat-file's options of the same name?

I'd much rather have support for ^{notes} (or similar) in the rev-parse 
machinery, so that you could look up deadbeef's notes by passing 
"deadbeef^{notes}" to 'git cat-file --batch'.

> > What worries me is that you're going to get fan-outs when there are
> > LOTS of notes, and that's precisely the kind of situation where you
> > _don't_ want to go through all the notes to pick the ones you're only
> > interested in.
> 
> Right.  This method would be contrary to the goals of fan-out schemes...
> well, we could use 'git ls-tree' without '-r' option, or simply
> 'git cat-file --batch' to read trees (note that we would get raw,
> unformatted tree, which is parseable with Perl, but it is not that easy),
> and go down level-by-level.

IMHO, it's much better/nicer to re-use the notes code for parsing note 
trees. See above suggestion on deadbeef^{notes}.

> > If we have a guarantee that the fan-outs follow a 2/[2/...] scheme,
> > the open2 approach might still be the best way to go, by just trying
> > not only namespace:xxxxx...xxx but also namespace:xx/xxxxx etc.
> > Horrible, but could still be coalesced in a single call. It mgiht also
> > be optimized to stop at the first successfull hit in a namespace.
> 
> Nice trick!  It seems like quite a good idea... but it would absolutely
> require using 'git cat-file --batch' rather than one git-show per try.

Still, I'd still much rather use the notes.c code itself for doing this 
since it should always be the fastest (not to mention future-proof) way of 
making lookups in the notes tree.


...Johan

-- 
Johan Herland, <johan@herland.net>
www.herland.net