From: Junio C Hamano <gitster@pobox.com>
To: Derrick Stolee <stolee@gmail.com>
Cc: Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org, me@ttaylorr.com, l.s.r@web.de,
szeder.dev@gmail.com, Chris Torek <chris.torek@gmail.com>,
Derrick Stolee <derrickstolee@github.com>,
Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH v2 12/17] chunk-format: create read chunk API
Date: Fri, 05 Feb 2021 11:37:53 -0800 [thread overview]
Message-ID: <xmqqeehu1f1q.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <1278de82-417c-a6ee-a5fe-055fa0ef1903@gmail.com> (Derrick Stolee's message of "Fri, 5 Feb 2021 07:19:52 -0500")
Derrick Stolee <stolee@gmail.com> writes:
>>> + chunk_id = get_be32(table_of_contents);
>>> + if (chunk_id) {
>>> + error(_("final chunk has non-zero id %"PRIx32""), chunk_id);
>>> + return -1;
>>> + }
>>
>> Shouldn't we be validating the size component associated with this
>> "id=0" fake chunk that appears at the end as well?
No, please disregard this comment, which was based on my incorrect
understanding of the "size" field associated with this fake ID==0
chunk (I incorrectly thought the size had something to do with the
file header plus TOC, but it is not---it is to allow discovering the
size of the last chunk by being a sentinel that records the offset
of an extra chunk at the end that does not actually exist).
> I like this, but why not just use pair_chunk_fn inside of
> the implementation of pair_chunk() so callers have an easy
> interface.
Yes, I didn't realize that earlier design iteration resulted in the
introduction of the "pair_chunk()" after discovering that it often
is necessary to just note the address where the data begins, so I
am OK to leave something like pair_chunk() as a public interface,
and implementing the pair_chunk() helper like you suggest would be a
perfectly fine way to do so.
It however is curious that the callers who use pair_chunk() do not
get the same quality of data as read_chunk() callers.
The users of pair_chunk() presumably are not ready to (or simply do
not want to) process the data immediately by using read_chunk() with
callback, but when they get ready to process the data, unlike
read_chunk callbacks, they do not get to learn how much they ought
to process---all they learn is the address of the beginning of the
chunk. I do not see a way to write pair_chunk() users safely to
guarantee that they do not overrun at the tail end of the chunk they
are processing.
Thanks.
next prev parent reply other threads:[~2021-02-05 19:44 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-26 16:01 [PATCH 00/17] Refactor chunk-format into an API Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 01/17] commit-graph: anonymize data in chunk_write_fn Derrick Stolee via GitGitGadget
2021-01-27 1:53 ` Chris Torek
2021-01-27 2:36 ` Taylor Blau
2021-01-26 16:01 ` [PATCH 02/17] chunk-format: create chunk format write API Derrick Stolee via GitGitGadget
2021-01-27 2:42 ` Taylor Blau
2021-01-27 13:49 ` Derrick Stolee
2021-01-26 16:01 ` [PATCH 03/17] commit-graph: use chunk-format " Derrick Stolee via GitGitGadget
2021-01-27 2:47 ` Taylor Blau
2021-01-26 16:01 ` [PATCH 04/17] midx: rename pack_info to write_midx_context Derrick Stolee via GitGitGadget
2021-01-27 2:49 ` Taylor Blau
2021-01-26 16:01 ` [PATCH 05/17] midx: use context in write_midx_pack_names() Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 06/17] midx: add entries to write_midx_context Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 07/17] midx: add pack_perm " Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 08/17] midx: add num_large_offsets " Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 09/17] midx: return success/failure in chunk write methods Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 10/17] midx: drop chunk progress during write Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 11/17] midx: use chunk-format API in write_midx_internal() Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 12/17] chunk-format: create read chunk API Derrick Stolee via GitGitGadget
2021-01-27 3:02 ` Taylor Blau
2021-01-26 16:01 ` [PATCH 13/17] commit-graph: use chunk-format read API Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 14/17] midx: " Derrick Stolee via GitGitGadget
2021-01-27 3:06 ` Taylor Blau
2021-01-27 13:50 ` Derrick Stolee
2021-01-26 16:01 ` [PATCH 15/17] midx: use 64-bit multiplication for chunk sizes Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 16/17] chunk-format: restore duplicate chunk checks Derrick Stolee via GitGitGadget
2021-01-26 16:01 ` [PATCH 17/17] chunk-format: add technical docs Derrick Stolee via GitGitGadget
2021-01-26 22:37 ` [PATCH 00/17] Refactor chunk-format into an API Junio C Hamano
2021-01-27 2:29 ` Taylor Blau
2021-01-27 15:01 ` [PATCH v2 " Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 01/17] commit-graph: anonymize data in chunk_write_fn Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 02/17] chunk-format: create chunk format write API Derrick Stolee via GitGitGadget
2021-02-04 21:24 ` Junio C Hamano
2021-02-04 22:40 ` Junio C Hamano
2021-02-05 11:37 ` Derrick Stolee
2021-02-05 19:25 ` Junio C Hamano
2021-01-27 15:01 ` [PATCH v2 03/17] commit-graph: use chunk-format " Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 04/17] midx: rename pack_info to write_midx_context Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 05/17] midx: use context in write_midx_pack_names() Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 06/17] midx: add entries to write_midx_context Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 07/17] midx: add pack_perm " Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 08/17] midx: add num_large_offsets " Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 09/17] midx: return success/failure in chunk write methods Derrick Stolee via GitGitGadget
2021-02-04 22:59 ` Junio C Hamano
2021-02-05 11:42 ` Derrick Stolee
2021-01-27 15:01 ` [PATCH v2 10/17] midx: drop chunk progress during write Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 11/17] midx: use chunk-format API in write_midx_internal() Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 12/17] chunk-format: create read chunk API Derrick Stolee via GitGitGadget
2021-02-04 23:40 ` Junio C Hamano
2021-02-05 12:19 ` Derrick Stolee
2021-02-05 19:37 ` Junio C Hamano [this message]
2021-02-08 22:26 ` Junio C Hamano
2021-02-09 1:33 ` Derrick Stolee
2021-02-09 20:47 ` Junio C Hamano
2021-01-27 15:01 ` [PATCH v2 13/17] commit-graph: use chunk-format read API Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 14/17] midx: " Derrick Stolee via GitGitGadget
2021-01-27 15:01 ` [PATCH v2 15/17] midx: use 64-bit multiplication for chunk sizes Derrick Stolee via GitGitGadget
2021-02-05 0:00 ` Junio C Hamano
2021-02-05 10:59 ` Chris Torek
2021-02-05 20:41 ` Junio C Hamano
2021-02-06 20:35 ` Chris Torek
2021-02-05 12:30 ` Derrick Stolee
2021-02-05 19:42 ` Junio C Hamano
2021-02-07 19:50 ` SZEDER Gábor
2021-02-08 5:41 ` Junio C Hamano
2021-01-27 15:01 ` [PATCH v2 16/17] chunk-format: restore duplicate chunk checks Derrick Stolee via GitGitGadget
2021-02-05 0:05 ` Junio C Hamano
2021-02-05 12:31 ` Derrick Stolee
2021-01-27 15:01 ` [PATCH v2 17/17] chunk-format: add technical docs Derrick Stolee via GitGitGadget
2021-02-05 0:15 ` Junio C Hamano
2021-01-27 16:03 ` [PATCH v2 00/17] Refactor chunk-format into an API Taylor Blau
2021-02-05 2:08 ` Junio C Hamano
2021-02-05 2:27 ` Derrick Stolee
2021-02-05 14:30 ` [PATCH v3 " Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 01/17] commit-graph: anonymize data in chunk_write_fn Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 02/17] chunk-format: create chunk format write API Derrick Stolee via GitGitGadget
2021-02-07 21:13 ` SZEDER Gábor
2021-02-08 13:44 ` Derrick Stolee
2021-02-11 19:43 ` SZEDER Gábor
2021-02-05 14:30 ` [PATCH v3 03/17] commit-graph: use chunk-format " Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 04/17] midx: rename pack_info to write_midx_context Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 05/17] midx: use context in write_midx_pack_names() Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 06/17] midx: add entries to write_midx_context Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 07/17] midx: add pack_perm " Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 08/17] midx: add num_large_offsets " Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 09/17] midx: return success/failure in chunk write methods Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 10/17] midx: drop chunk progress during write Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 11/17] midx: use chunk-format API in write_midx_internal() Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 12/17] chunk-format: create read chunk API Derrick Stolee via GitGitGadget
2021-02-07 20:20 ` SZEDER Gábor
2021-02-08 13:35 ` Derrick Stolee
2021-02-05 14:30 ` [PATCH v3 13/17] commit-graph: use chunk-format read API Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 14/17] midx: " Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 15/17] midx: use 64-bit multiplication for chunk sizes Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 16/17] chunk-format: restore duplicate chunk checks Derrick Stolee via GitGitGadget
2021-02-05 14:30 ` [PATCH v3 17/17] chunk-format: add technical docs Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 00/17] Refactor chunk-format into an API Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 01/17] commit-graph: anonymize data in chunk_write_fn Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 02/17] chunk-format: create chunk format write API Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 03/17] commit-graph: use chunk-format " Derrick Stolee via GitGitGadget
2021-02-24 16:52 ` SZEDER Gábor
2021-02-24 17:12 ` Taylor Blau
2021-02-24 17:52 ` Derrick Stolee
2021-02-24 19:44 ` Junio C Hamano
2021-02-18 14:07 ` [PATCH v4 04/17] midx: rename pack_info to write_midx_context Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 05/17] midx: use context in write_midx_pack_names() Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 06/17] midx: add entries to write_midx_context Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 07/17] midx: add pack_perm " Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 08/17] midx: add num_large_offsets " Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 09/17] midx: return success/failure in chunk write methods Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 10/17] midx: drop chunk progress during write Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 11/17] midx: use chunk-format API in write_midx_internal() Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 12/17] chunk-format: create read chunk API Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 13/17] commit-graph: use chunk-format read API Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 14/17] midx: " Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 15/17] midx: use 64-bit multiplication for chunk sizes Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 16/17] chunk-format: restore duplicate chunk checks Derrick Stolee via GitGitGadget
2021-02-18 14:07 ` [PATCH v4 17/17] chunk-format: add technical docs Derrick Stolee via GitGitGadget
2021-02-18 21:47 ` Junio C Hamano
2021-02-19 12:42 ` Derrick Stolee
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