From: Junio C Hamano <gitster@pobox.com>
To: Derrick Stolee <stolee@gmail.com>
Cc: git@vger.kernel.org, sbeller@google.com, pclouds@gmail.com,
avarab@gmail.com, dstolee@microsoft.com
Subject: Re: [PATCH v3 06/24] multi-pack-index: load into memory
Date: Mon, 09 Jul 2018 12:08:14 -0700 [thread overview]
Message-ID: <xmqq36wsdy75.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20180706005321.124643-7-dstolee@microsoft.com> (Derrick Stolee's message of "Thu, 5 Jul 2018 20:53:03 -0400")
Derrick Stolee <stolee@gmail.com> writes:
> +struct multi_pack_index *load_multi_pack_index(const char *object_dir)
> +{
> + struct multi_pack_index *m = NULL;
> + int fd;
> + struct stat st;
> + size_t midx_size;
> + void *midx_map = NULL;
> + uint32_t hash_version;
> + char *midx_name = get_midx_filename(object_dir);
> +
> + fd = git_open(midx_name);
> +
> + if (fd < 0)
> + goto cleanup_fail;
> + if (fstat(fd, &st)) {
> + error_errno(_("failed to read %s"), midx_name);
> + goto cleanup_fail;
> + }
> +
> + midx_size = xsize_t(st.st_size);
> +
> + if (midx_size < MIDX_MIN_SIZE) {
> + close(fd);
With the use of "do things normally and jump to cleanup-fail label"
pattern, I think you do not want the close() here (unless you also
assign -1 to fd yourself, but that is a pointless workaround).
Another goto we see above after fstat() failure correctly omits it.
> + error(_("multi-pack-index file %s is too small"), midx_name);
> + goto cleanup_fail;
> + }
> +
> + FREE_AND_NULL(midx_name);
This correctly calls free-and-null not just free (otherwise we'd
break the cleanup-fail procedure below), which is good.
> + midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
> +
> + m = xcalloc(1, sizeof(*m) + strlen(object_dir) + 1);
> + strcpy(m->object_dir, object_dir);
Hmph, I thought we had FLEX_ALLOC_*() convenience functions exactly
for doing things like this more safely.
> + m->fd = fd;
> + m->data = midx_map;
> + m->data_len = midx_size;
> +
> + m->signature = get_be32(m->data);
> + if (m->signature != MIDX_SIGNATURE) {
> + error(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
> + m->signature, MIDX_SIGNATURE);
> + goto cleanup_fail;
> + }
> +
> + m->version = m->data[MIDX_BYTE_FILE_VERSION];
> + if (m->version != MIDX_VERSION) {
> + error(_("multi-pack-index version %d not recognized"),
> + m->version);
> + goto cleanup_fail;
> + }
> +
> + hash_version = m->data[MIDX_BYTE_HASH_VERSION];
> + if (hash_version != MIDX_HASH_VERSION) {
> + error(_("hash version %u does not match"), hash_version);
> + goto cleanup_fail;
> + }
> + m->hash_len = MIDX_HASH_LEN;
> +
> + m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
> +
> + m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
> +
> + return m;
> +cleanup_fail:
> + /* no need to check for NULL when freeing */
I wonder who the target reader of this comment is. We certainly are
not in the business of C language newbies.
If this _were_ a commit that looked like this:
- if (ptr)
- free(ptr);
+ /* no need to check for NULL when freeing */
+ free(ptr);
then it might be more understandable, but it still is wrong (such a
comment does not help understanding the new code, which is the only
thing the people who read the comment sees, without knowing what was
there previously---it belongs to the commit log message as a rationale
to make that change).
> diff --git a/midx.h b/midx.h
> index dbdbe9f873..2d83dd9ec1 100644
> --- a/midx.h
> +++ b/midx.h
> @@ -1,6 +1,10 @@
> #ifndef __MIDX_H__
> #define __MIDX_H__
>
> +struct multi_pack_index;
I actually was quite surprised that this struct is defined in
object-store.h and not here. It feels the other way around.
The raw_object_store needs to know that such an in-core structure
might exist as an optional feature in an object store, but as an
optional feature, I suspect that it has a pointer to an instance of
multi_pack_index, instead of embedding the struct itself in it, so I
would have expected to see an "I am only telling you that there is a
struct with this name, but I am leaving it opaque as you do not have
any business looking inside the struct yourself. You only need to
be aware of the type's existence and a pointer to it so that you can
call helpers that know what's inside and that should be sufficient
for your needs." decl like this in object-store.h and instead an
actual implementation in here.
next prev parent reply other threads:[~2018-07-09 19:08 UTC|newest]
Thread overview: 192+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-07 14:03 [PATCH 00/23] Multi-pack-index (MIDX) Derrick Stolee
2018-06-07 14:03 ` [PATCH 01/23] midx: add design document Derrick Stolee
2018-06-11 19:04 ` Stefan Beller
2018-06-18 18:48 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 02/23] midx: add midx format details to pack-format.txt Derrick Stolee
2018-06-11 19:19 ` Stefan Beller
2018-06-18 19:01 ` Derrick Stolee
2018-06-18 19:41 ` Stefan Beller
2018-06-07 14:03 ` [PATCH 03/23] midx: add midx builtin Derrick Stolee
2018-06-07 17:20 ` Duy Nguyen
2018-06-18 19:23 ` Derrick Stolee
2018-06-11 21:02 ` Stefan Beller
2018-06-18 19:40 ` Derrick Stolee
2018-06-18 19:55 ` Stefan Beller
2018-06-18 19:58 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 04/23] midx: add 'write' subcommand and basic wiring Derrick Stolee
2018-06-07 17:27 ` Duy Nguyen
2018-06-07 14:03 ` [PATCH 05/23] midx: write header information to lockfile Derrick Stolee
2018-06-07 17:35 ` Duy Nguyen
2018-06-12 15:00 ` Duy Nguyen
2018-06-19 12:54 ` Derrick Stolee
2018-06-19 14:59 ` Duy Nguyen
2018-06-19 15:24 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 06/23] midx: struct midxed_git and 'read' subcommand Derrick Stolee
2018-06-07 17:54 ` Duy Nguyen
2018-06-20 13:13 ` Derrick Stolee
2018-06-07 18:31 ` Duy Nguyen
2018-06-20 13:33 ` Derrick Stolee
2018-06-20 15:07 ` Duy Nguyen
2018-06-20 16:39 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 07/23] midx: expand test data Derrick Stolee
2018-06-07 14:03 ` [PATCH 08/23] midx: read packfiles from pack directory Derrick Stolee
2018-06-07 18:03 ` Duy Nguyen
2018-06-20 16:33 ` [PATCH] packfile: generalize pack directory list Derrick Stolee
2018-06-07 14:03 ` [PATCH 09/23] midx: write pack names in chunk Derrick Stolee
2018-06-07 18:26 ` Duy Nguyen
2018-06-21 15:25 ` Derrick Stolee
2018-06-21 17:38 ` Junio C Hamano
2018-06-22 18:25 ` Derrick Stolee
2018-06-22 18:31 ` Junio C Hamano
2018-06-22 18:32 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 10/23] midx: write a lookup into the pack names chunk Derrick Stolee
2018-06-09 16:43 ` Duy Nguyen
2018-06-21 17:23 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 11/23] midx: sort and deduplicate objects from packfiles Derrick Stolee
2018-06-09 17:07 ` Duy Nguyen
2018-06-21 17:54 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 12/23] midx: write object ids in a chunk Derrick Stolee
2018-06-09 17:25 ` Duy Nguyen
2018-06-07 14:03 ` [PATCH 13/23] midx: write object id fanout chunk Derrick Stolee
2018-06-09 17:28 ` Duy Nguyen
2018-06-21 19:49 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 14/23] midx: write object offsets Derrick Stolee
2018-06-09 17:41 ` Duy Nguyen
2018-06-07 14:03 ` [PATCH 15/23] midx: create core.midx config setting Derrick Stolee
2018-06-07 14:03 ` [PATCH 16/23] midx: prepare midxed_git struct Derrick Stolee
2018-06-09 17:47 ` Duy Nguyen
2018-06-07 14:03 ` [PATCH 17/23] midx: read objects from multi-pack-index Derrick Stolee
2018-06-09 17:56 ` Duy Nguyen
2018-06-21 20:03 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 18/23] midx: use midx in abbreviation calculations Derrick Stolee
2018-06-09 18:01 ` Duy Nguyen
2018-06-22 18:38 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 19/23] midx: use existing midx when writing new one Derrick Stolee
2018-06-07 14:03 ` [PATCH 20/23] midx: use midx in approximate_object_count Derrick Stolee
2018-06-09 18:03 ` Duy Nguyen
2018-06-22 18:39 ` Derrick Stolee
2018-06-07 14:03 ` [PATCH 21/23] midx: prevent duplicate packfile loads Derrick Stolee
2018-06-09 18:05 ` Duy Nguyen
2018-06-07 14:03 ` [PATCH 22/23] midx: use midx to find ref-deltas Derrick Stolee
2018-06-07 14:03 ` [PATCH 23/23] midx: clear midx on repack Derrick Stolee
2018-06-09 18:13 ` Duy Nguyen
2018-06-22 18:44 ` Derrick Stolee
2018-06-07 14:06 ` [PATCH 00/23] Multi-pack-index (MIDX) Derrick Stolee
2018-06-07 14:45 ` Ævar Arnfjörð Bjarmason
2018-06-07 14:54 ` Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 00/24] " Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 01/24] multi-pack-index: add design document Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 02/24] multi-pack-index: add format details Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 03/24] multi-pack-index: add builtin Derrick Stolee
2018-06-25 19:15 ` Junio C Hamano
2018-06-25 14:34 ` [PATCH v2 04/24] multi-pack-index: add 'write' verb Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 05/24] midx: write header information to lockfile Derrick Stolee
2018-06-25 19:19 ` Junio C Hamano
2018-07-05 19:13 ` Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 06/24] multi-pack-index: load into memory Derrick Stolee
2018-06-25 19:38 ` Junio C Hamano
2018-07-05 14:19 ` Derrick Stolee
2018-07-05 18:58 ` Eric Sunshine
2018-07-06 19:20 ` Junio C Hamano
2018-06-25 14:34 ` [PATCH v2 07/24] multi-pack-index: expand test data Derrick Stolee
2018-06-25 19:45 ` Junio C Hamano
2018-06-25 14:34 ` [PATCH v2 08/24] packfile: generalize pack directory list Derrick Stolee
2018-06-25 19:57 ` Junio C Hamano
2018-06-25 14:34 ` [PATCH v2 09/24] multi-pack-index: read packfile list Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 10/24] multi-pack-index: write pack names in chunk Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 11/24] midx: read pack names into array Derrick Stolee
2018-06-25 23:52 ` Eric Sunshine
2018-06-25 14:34 ` [PATCH v2 12/24] midx: sort and deduplicate objects from packfiles Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 13/24] midx: write object ids in a chunk Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 14/24] midx: write object id fanout chunk Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 15/24] midx: write object offsets Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 16/24] config: create core.multiPackIndex setting Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 17/24] midx: prepare midxed_git struct Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 18/24] midx: read objects from multi-pack-index Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 19/24] midx: use midx in abbreviation calculations Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 20/24] midx: use existing midx when writing new one Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 21/24] midx: use midx in approximate_object_count Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 22/24] midx: prevent duplicate packfile loads Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 23/24] packfile: skip loading index if in multi-pack-index Derrick Stolee
2018-06-25 14:34 ` [PATCH v2 24/24] midx: clear midx on repack Derrick Stolee
2018-07-06 0:52 ` [PATCH v3 00/24] Multi-pack-index (MIDX) Derrick Stolee
2018-07-06 0:52 ` [PATCH v3 01/24] multi-pack-index: add design document Derrick Stolee
2018-07-06 0:52 ` [PATCH v3 02/24] multi-pack-index: add format details Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 03/24] multi-pack-index: add builtin Derrick Stolee
2018-07-06 3:54 ` Eric Sunshine
2018-07-06 0:53 ` [PATCH v3 04/24] multi-pack-index: add 'write' verb Derrick Stolee
2018-07-06 4:07 ` Eric Sunshine
2018-07-06 0:53 ` [PATCH v3 05/24] midx: write header information to lockfile Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 06/24] multi-pack-index: load into memory Derrick Stolee
2018-07-06 4:19 ` Eric Sunshine
2018-07-06 5:18 ` Eric Sunshine
2018-07-09 19:08 ` Junio C Hamano [this message]
2018-07-12 16:06 ` Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 07/24] multi-pack-index: expand test data Derrick Stolee
2018-07-06 4:36 ` Eric Sunshine
2018-07-06 5:20 ` Eric Sunshine
2018-07-12 14:10 ` Derrick Stolee
2018-07-12 18:02 ` Eric Sunshine
2018-07-12 18:06 ` Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 08/24] packfile: generalize pack directory list Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 09/24] multi-pack-index: read packfile list Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 10/24] multi-pack-index: write pack names in chunk Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 11/24] midx: read pack names into array Derrick Stolee
2018-07-06 4:58 ` Eric Sunshine
2018-07-06 0:53 ` [PATCH v3 12/24] midx: sort and deduplicate objects from packfiles Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 13/24] midx: write object ids in a chunk Derrick Stolee
2018-07-06 5:04 ` Eric Sunshine
2018-07-06 0:53 ` [PATCH v3 14/24] midx: write object id fanout chunk Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 15/24] midx: write object offsets Derrick Stolee
2018-07-06 5:27 ` Eric Sunshine
2018-07-12 16:33 ` Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 16/24] config: create core.multiPackIndex setting Derrick Stolee
2018-07-06 5:39 ` Eric Sunshine
2018-07-12 13:19 ` Derrick Stolee
2018-07-12 16:30 ` Derrick Stolee
2018-07-11 9:48 ` SZEDER Gábor
2018-07-12 13:01 ` Derrick Stolee
2018-07-12 13:31 ` SZEDER Gábor
2018-07-12 15:40 ` Derrick Stolee
2018-07-12 17:29 ` Junio C Hamano
2018-07-06 0:53 ` [PATCH v3 17/24] midx: prepare midxed_git struct Derrick Stolee
2018-07-06 5:41 ` Eric Sunshine
2018-07-06 0:53 ` [PATCH v3 18/24] midx: read objects from multi-pack-index Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 19/24] midx: use midx in abbreviation calculations Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 20/24] midx: use existing midx when writing new one Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 21/24] midx: use midx in approximate_object_count Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 22/24] midx: prevent duplicate packfile loads Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 23/24] packfile: skip loading index if in multi-pack-index Derrick Stolee
2018-07-06 0:53 ` [PATCH v3 24/24] midx: clear midx on repack Derrick Stolee
2018-07-06 5:52 ` Eric Sunshine
2018-07-12 19:39 ` [PATCH v4 00/23] Multi-pack-index (MIDX) Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 01/23] multi-pack-index: add design document Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 02/23] multi-pack-index: add format details Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 03/23] multi-pack-index: add builtin Derrick Stolee
2018-07-20 18:22 ` Junio C Hamano
2018-07-20 22:15 ` brian m. carlson
2018-07-20 22:28 ` Junio C Hamano
2018-07-12 19:39 ` [PATCH v4 04/23] multi-pack-index: add 'write' verb Derrick Stolee
2018-07-12 22:56 ` Eric Sunshine
2018-07-12 19:39 ` [PATCH v4 05/23] midx: write header information to lockfile Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 06/23] multi-pack-index: load into memory Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 07/23] t5319: expand test data Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 08/23] packfile: generalize pack directory list Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 09/23] multi-pack-index: read packfile list Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 10/23] multi-pack-index: write pack names in chunk Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 11/23] midx: read pack names into array Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 12/23] midx: sort and deduplicate objects from packfiles Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 13/23] midx: write object ids in a chunk Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 14/23] midx: write object id fanout chunk Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 15/23] midx: write object offsets Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 16/23] config: create core.multiPackIndex setting Derrick Stolee
2018-07-12 21:05 ` Junio C Hamano
2018-07-13 0:50 ` Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 17/23] midx: read objects from multi-pack-index Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 18/23] midx: use midx in abbreviation calculations Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 19/23] midx: use existing midx when writing new one Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 20/23] midx: use midx in approximate_object_count Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 21/23] midx: prevent duplicate packfile loads Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 22/23] packfile: skip loading index if in multi-pack-index Derrick Stolee
2018-07-12 19:39 ` [PATCH v4 23/23] midx: clear midx on repack Derrick Stolee
2018-07-12 21:11 ` [PATCH v4 00/23] Multi-pack-index (MIDX) Junio C Hamano
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