Re: [RFC] Long running Git clean/smudge filter

On 10 Jul 2016, at 17:10, Joey Hess [off-list ref] wrote:

larsxschneider@gmail.com wrote:

quoted

(2) Joey's topic, which is the base for my patch, looks stalled for more than
2 weeks:
http://thread.gmane.org/gmane.comp.version-control.git/297994/focus=298006
I would be happy to address Junio's comments and post a reroll. However,
I don't want to interfere with Joey's plans.

I've been on vacation and plan to get back to that in the upcoming week.

Good to hear :-) ! I hope you had a great vacation!

quoted

@Joey (in case you are reading this):
My patch changes your initial idea quite a bit. However, I believe it is an
improvement that could be beneficial for git-annex, too. Would you prefer to
work with me on the combination of our ideas (file clean/smudge + long running
clean/smudge processes) or would you prefer to keep your interface?

Long running filters mean that you need a more complicated protocol to
speak over the pipes. Seems that such a protocol could be designed to work
with the original smudge/clean filters as well as with my
smudgeToFile/cleanFromFile filters. Assuming that there's a way to
tell whether the filters support being long-running or not.

Note that the interface we arrived at for smudgeToFile/cleanFromFile is as
similar as possible to smudge/clean, so the filter developer only has to
change one thing. That's a big plus, and so I don't like diverging the
two interfaces.

I understand, thanks for the clarification. My plan is to implement long running 
filters only for smudgeToFile/cleanFromFile (at least initially) as this should
solve the major pain point already and is relatively straight forward.

What do you think about this kind of config? Any idea for a better config name?

[filter "bar"]
    clean = foo1 %f
    smudge = foo2 %f
    cleanFromFile foo3
    smudgeToFile foo4
    longRunning = true

I think it would be easy to support both of our interfaces in parallel. Do
you understand why the "async" API is necessary?
https://github.com/larsxschneider/git/blob/74e22bd4e0b505785fa8ffc2ef15721909635d1c/convert.c#L585-L599

Would you be OK if I implement smudgeToFile/cleanFromFile as separate
"apply_filter" function as I have prototyped here:
https://github.com/larsxschneider/git/blob/74e22bd4e0b505785fa8ffc2ef15721909635d1c/convert.c#L1143-L1146
https://github.com/larsxschneider/git/blob/74e22bd4e0b505785fa8ffc2ef15721909635d1c/convert.c#L402-L488


Thanks,
Lars