Re: [PATCH] denser delta header encoding

From: Linus Torvalds <torvalds@osdl.org>
Date: Jun 29, 2005, 05:21 UTC
Message-ID: <Pine.LNX.4.58.0506282217010.19755@ppc970.osdl.org>
In-Reply-To: <7vmzp9kbcf.fsf@assigned-by-dhcp.cox.net>

On Tue, 28 Jun 2005, Junio C Hamano wrote:

>
> Linus, please do not apply this as is.

Argh. Too late.

> There are code other than what Nico updated with this patch in
> sha1_file.c that also need updating, that count the number of
> bytes in the delta-patch result by reading from the delta
> header.

Hmm.. I tested this (along with my change to make the pack object also use the little-endian size encoding) with "gitk" on a packed git archive, and with git-unpack-objects. So it can't break _too_ seriously. Is it the "git-cat-file -s" thing that gets the wrong answer?

Ahh. I see it. "packed_delta_info()". And it looks like "diff" uses it too. Oh, for the copy and rename detection. I don't think I tested that part, nope.

Show 14 quoted lines

> I wonder if we can have a helper function in delta suite
> somewhere (maybe in diff-delta.c):
> 
>     int look_at_delta_header(void **delta_data, ulong delta_size,
>     	                     ulong *src_size, ulong *dst_size)
> 
> that:
> 
>     - checks delta size and barf if it is small;
>     - reads the header and fills src_size and dst_size;
>     - advances *delta_data pointer;
> 
> and have count-delta, patch-delta and sha1_file.c users use it
> consistently.  Nico, what do you think?

Sounds like a good idea.

		Linus