From: Junio C Hamano <gitster@pobox•com>
To: Mike Hommey <mh@glandium•org>
Cc: Jeff King <peff@peff•net>, git@vger•kernel.org
Subject: Re: fast-import deltas
Date: Tue, 01 Apr 2014 15:32:49 -0700 [thread overview]
Message-ID: <xmqqlhvoy92m.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <20140401221003.GA5923@glandium.org> (Mike Hommey's message of "Wed, 2 Apr 2014 07:10:03 +0900")
Mike Hommey <mh@glandium•org> writes:
> On Tue, Apr 01, 2014 at 10:14:02AM -0700, Junio C Hamano wrote:
> ...
>> Unless you already have your change in the xdelta on hand, or the
>> format your foreign change is in gives sufficient information to
>> produce a corresponding xdelta without looking at the content that
>> your foreign change applies to, it is silly to try to convert your
>> foreign change into xdelta and feed it to fast-import.
>
> The patch format I'm getting from mercurial boils down to:
> - replace N bytes from offset in the source material with the given
> M bytes.
> Which can easily be converted to xdelta without looking at the original.
If that is the case, and if you can identify the original in a way
fast-import can understand, it might be interesting [*1*] to add support
for accepting <base object, xdelta> pair in place of blob data, as
Jonathan already hinted earlier.
It would not be sufficient for the receiving fast-import to store
the delta data to its output---it needs to make sure that the base
object is stored in the same output file as well, but that should
not be too complicated.
[Footnote]
*1* I am still not sure how useful the feature would be outside
slurping from Hg and Git---for obvious reasons, though. As long as
the change is to a cleanly isolated codepath, it would be OK, I
guess.
next prev parent reply other threads:[~2014-04-03 9:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-01 10:25 fast-import deltas Mike Hommey
2014-04-01 11:45 ` Jeff King
2014-04-01 13:07 ` Mike Hommey
2014-04-01 13:15 ` Jeff King
2014-04-01 14:18 ` Mike Hommey
2014-04-01 17:14 ` Junio C Hamano
2014-04-01 17:38 ` Jonathan Nieder
2014-04-01 22:10 ` Mike Hommey
2014-04-01 22:32 ` Junio C Hamano [this message]
2014-04-01 23:12 ` Mike Hommey
2014-04-01 23:29 ` Max Horn
2014-04-02 4:13 ` Mike Hommey
2014-04-09 17:44 ` Felipe Contreras
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