[PATCH 4/6] object-file: drop oid field from find_cached_object() return value
- From
Jeff King <peff@peff.net>
- Date
- Nov 18, 2024, 09:55 UTC
- Message-ID
- <20241118095515.GD3992317@coredump.intra.peff.net>
- In-Reply-To
- <20241118095423.GA3990835@coredump.intra.peff.net>
The pretend_object_file() function adds to an array mapping oids to object contents, which are later retrieved with find_cached_object(). We naturally need to store the oid for each entry, since it's the lookup key.
But find_cached_object() also returns a hard-coded empty_tree object. There we don't care about its oid field and instead compare against the_hash_algo->empty_tree. The oid field is left as all-zeroes.
This all works, but it means that the cached_object struct we return from find_cached_object() may or may not have a valid oid field, depend whether it is the hard-coded tree or came from pretend_object_file().
Nobody looks at the field, so there's no bug. But let's future-proof it by returning only the object contents themselves, not the oid. We'll continue to call this "struct cached_object", and the array entry mapping the key to those contents will be a "cached_object_entry".
This would also let us swap out the array for a better data structure (like a hashmap) if we chose, but there's not much point. The only code that adds an entry is git-blame, which adds at most a single entry per process.
Signed-off-by: Jeff King <peff@peff.net> --- object-file.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/object-file.c b/object-file.c index 4d4280543e..67a6731066 100644 --- a/object-file.c +++ b/object-file.c @@ -317,27 +317,28 @@ int hash_algo_by_length(int len) * to write them into the object store (e.g. a browse-only * application). */ -static struct cached_object { +static struct cached_object_entry { struct object_id oid; - enum object_type type; - const void *buf; - unsigned long size; + struct cached_object { + enum object_type type; + const void *buf; + unsigned long size; + } value; } *cached_objects; static int cached_object_nr, cached_object_alloc; static struct cached_object *find_cached_object(const struct object_id *oid) { static struct cached_object empty_tree = { - /* no oid needed; we'll look it up manually based on the_hash_algo */ .type = OBJ_TREE, .buf = "", }; int i; - struct cached_object *co = cached_objects; + struct cached_object_entry *co = cached_objects; for (i = 0; i < cached_object_nr; i++, co++) { if (oideq(&co->oid, oid)) - return co; + return &co->value; } if (oideq(oid, the_hash_algo->empty_tree)) return &empty_tree; @@ -1850,7 +1851,7 @@ int oid_object_info(struct repository *r, int pretend_object_file(void *buf, unsigned long len, enum object_type type, struct object_id *oid) { - struct cached_object *co; + struct cached_object_entry *co; char *co_buf; hash_object_file(the_hash_algo, buf, len, type, oid); @@ -1859,11 +1860,11 @@ int pretend_object_file(void *buf, unsigned long len, enum object_type type, return 0; ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc); co = &cached_objects[cached_object_nr++]; - co->size = len; - co->type = type; + co->value.size = len; + co->value.type = type; co_buf = xmalloc(len); memcpy(co_buf, buf, len); - co->buf = co_buf; + co->value.buf = co_buf; oidcpy(&co->oid, oid); return 0; }
-- 2.47.0.547.g778689293a