Re: [PATCH 2/2] sha1_file: remove read_packed_sha1()
From: Junio C Hamano <hidden>
Date: 2017-08-11 22:07:03
Jonathan Tan [off-list ref] writes:
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 <redacted> --- 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.
quoted hunk
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;