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From: Junio C Hamano <gitster@pobox.com>
To: Taylor Blau <me@ttaylorr.com>
Cc: "Eric W. Biederman" <ebiederm@gmail.com>,
	"brian m. carlson" <sandals@crustytoothpaste.net>,
	Elijah Newren <newren@gmail.com>,
	git@vger.kernel.org
Subject: Re: [PATCH v3] bulk-checkin: only support blobs in index_bulk_checkin
Date: Wed, 27 Sep 2023 09:26:46 -0700	[thread overview]
Message-ID: <xmqq7cobmvjt.fsf@gitster.g> (raw)
In-Reply-To: <ZRQ9aSeu/wpJERuV@nand.local> (Taylor Blau's message of "Wed, 27 Sep 2023 10:34:17 -0400")

Taylor Blau <me@ttaylorr.com> writes:

> I am not sure that I follow. If we have an address in memory from which
> we want to stream raw bytes directly to the packfile, that should work
> for all objects regardless of type, no?

For a single hash world, yes.  For keeping track of "the other hash"
and correspondence, you need to (1) interpret the contents of the
object (e.g., if you received a tree contents for SHA-1 repository,
you'd need to split them into tree entries and know which parts of
the bytestream are SHA-1 hashes of the tree contebnts), (2) come
up with the corresponding tree contents in the SHA-256 world (you
should be able to do that now you know SHA-1 names of the objects
directly referred to by the tree) and hash that using SHA-256, and
(3) remember the SHA-1 and the SHA-256 name correspondence of the
tree object you just hashed, in addition to the usual (4) hashing
the contents using SHA-1 hash algorithm without caring what the byte
stream represents.

  reply	other threads:[~2023-09-27 16:27 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-20  3:52 [PATCH v2] bulk-checkin: only support blobs in index_bulk_checkin Eric W. Biederman
2023-09-20  6:59 ` Junio C Hamano
2023-09-20 12:24   ` Eric W. Biederman
2023-09-26 15:58     ` [PATCH v3] " Eric W. Biederman
2023-09-26 21:48       ` Junio C Hamano
2023-09-27  1:38         ` Taylor Blau
2023-09-27  4:08           ` Junio C Hamano
2023-09-27 14:34             ` Taylor Blau
2023-09-27 16:26               ` Junio C Hamano [this message]
2023-09-27 20:06                 ` Eric W. Biederman
2023-09-27 20:13           ` Eric W. Biederman
2023-09-28  9:39       ` Oswald Buddenhagen

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