Re: [PATCH 2/2] sha1_file: remove read_packed_sha1()
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Aug 11, 2017, 22:06 UTC
- Message-ID
- <xmqqa835zrlt.fsf@gitster.mtv.corp.google.com>
- In-Reply-To
- <557fbeeac6a0f65d48ba0902f20c0650e75ae332.1502483486.git.jonathantanmy@google.com>
Jonathan Tan <jonathantanmy@google.com> writes:
Show 9 quoted lines
> Use read_object() in its place instead. This avoids duplication of code. > > This makes force_object_loose() slightly slower (because of a redundant > check of loose object storage), but only in the error case. > > Signed-off-by: Jonathan Tan <jonathantanmy@google.com> > --- > sha1_file.c | 26 +------------------------- > 1 file changed, 1 insertion(+), 25 deletions(-)
The original code insisted on reading from pack and never from a loose object, because it knew it would return early when it found a loose version. Now we allow a loose one to appear in the middle of force_object_loose() operation and happily read from it when we do not see a pack entry for the object---presumably because we are racing with another simultanous repack process, or something?---and then write it out as a new (and identical) loose object, which would not do any harm.
So this is not strictly a no-op conversion; I have a gut feeling that it would make it more robust, not less, in the presence of another racing repack process, but I haven't really thought through race scenarios that may make difference in its behaviour.
Show 44 quoted lines
> diff --git a/sha1_file.c b/sha1_file.c
> index 910109fd9..0f758eabf 100644
> --- a/sha1_file.c
> +++ b/sha1_file.c
> @@ -3062,30 +3062,6 @@ int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
> return type;
> }
>
> -static void *read_packed_sha1(const unsigned char *sha1,
> - enum object_type *type, unsigned long *size)
> -{
> - struct pack_entry e;
> - void *data;
> -
> - if (!find_pack_entry(sha1, &e))
> - return NULL;
> - data = cache_or_unpack_entry(e.p, e.offset, size, type);
> - if (!data) {
> - /*
> - * We're probably in deep shit, but let's try to fetch
> - * the required object anyway from another pack or loose.
> - * This should happen only in the presence of a corrupted
> - * pack, and is better than failing outright.
> - */
> - error("failed to read object %s at offset %"PRIuMAX" from %s",
> - sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
> - mark_bad_packed_object(e.p, sha1);
> - data = read_object(sha1, type, size);
> - }
> - return data;
> -}
> -
> int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
> unsigned char *sha1)
> {
> @@ -3468,7 +3444,7 @@ int force_object_loose(const unsigned char *sha1, time_t mtime)
>
> if (has_loose_object(sha1))
> return 0;
> - buf = read_packed_sha1(sha1, &type, &len);
> + buf = read_object(sha1, &type, &len);
> if (!buf)
> return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
> hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;