From: Lars Schneider <larsxschneider@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Git Mailing List <git@vger.kernel.org>, Johannes Sixt <j6t@kdbg.org>
Subject: Re: Looking for help to understand external filter driver code
Date: Tue, 19 Jul 2016 22:44:53 +0200 [thread overview]
Message-ID: <7B44C694-7CB2-411D-9CC6-7334CCBAD20B@gmail.com> (raw)
In-Reply-To: <xmqqlh0xfoho.fsf@gitster.mtv.corp.google.com>
On 19 Jul 2016, at 20:53, Junio C Hamano <gitster@pobox.com> wrote:
> Junio C Hamano <gitster@pobox.com> writes:
>
>> The key benefit of this arrangement is the above can be done without
>> having to do poll() to flip between reading and writing that is
>> needed to avoid deadlocking, which kept the code simpler. A later
>> conversion of the write side into async does not fundamentally
>> change anything from the original arrangement.
>
> Translation: I was too lazy to worry about doing poll()/select()
> when I did it originally. As long as you can do so correctly, be my
> guest to reduce one process by having the main process do both
> reading and writing.
>
> ;-)
Thanks a lot for this explanation. My goal is to add an option to
the clean/smudge filter config that instructs Git to keep the
external filter process running. Whenever Git encounters a file
to be filtered then it would continue to talk to the filter process
over a simple pipe protocol:
Git writes --> 4 byte filename length
Git writes --> filename string
Git writes --> 4 byte content length
Git writes --> content string
Git reads <-- 4 byte filtered content length
Git reads <-- filtered content
I still need to read more about poll()/select() but it looks to me
as if these functions are only required if Git doesn't know what to
expect. With the sketched protocol above that wouldn't be the case.
Therefore, I wonder if I would need to use poll()/select()?
Thanks,
Lars
next prev parent reply other threads:[~2016-07-19 20:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-19 16:40 Looking for help to understand external filter driver code Lars Schneider
2016-07-19 17:56 ` Junio C Hamano
2016-07-19 18:53 ` Junio C Hamano
2016-07-19 20:44 ` Lars Schneider [this message]
2016-07-19 21:33 ` Junio C Hamano
2016-07-19 22:01 ` Lars Schneider
2016-07-20 2:33 ` Torsten Bögershausen
2016-07-20 8:59 ` Jakub Narębski
2016-07-20 9:43 ` Lars Schneider
2016-07-20 13:49 ` Jeff King
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