Re: [PATCH 0/3] fast textconv

[Jeff King <peff@peff.net>]

On Sun, Mar 28, 2010 at 06:09:35PM +0200, Michael J Gruber wrote:

> Really, "Notes!" was my first thought even before reading 2. Happy to
> have found a like mind :)
> 
> This would still need a mechanism where the conv helper gets the blob's
> SHA1 - hey, it's there in your patch...
> 
> How about:
> 
> Set fasttextconv=notestextconv
> 
> notestextconv does the following:
> 
> - If $sha1 has a note in refs/notes/bikeshed display it.
> - If not create one and then display it.
> 
> In fact, the creation could be done using the textconv setting!

If I understand you right, you are proposing a separate program
that you would pass as a fasttextconv helper, and that would look in a
notes tree. So you would still have a per-diff fork/exec, and pipe all
the data.

I was thinking of actually doing it in-core, so cache hits would be as
lightweight as a notes lookup (and cache misses obviously would still
fork/exec a helper, but we don't care too much since the helper's time
to convert will dominate in that path).

> Pruning the cache is done be deleting the refs/notes/bikeshed ref,
> truncating it by truncating it's DAG (filter-branch...).

Yeah, that would work. It just means it's one more thing the user has to
deal with. I didn't want to have to introduce a "git textconv"
management helper. ;)

-Peff