Re: [PATCH 1/1] Add a helper to reverse index_pos_to_insert_pos()

From: Johannes Sixt <j6t@kdbg.org>
Date: Oct 8, 2019, 21:03 UTC
Message-ID: <75a9c7ce-893c-6341-ba8d-eed3ccba7ee3@kdbg.org>
In-Reply-To: <81648344bbab4219c0bfc60d1e5f02473ea7d495.1570517329.git.gitgitgadget@gmail.com>

Am 08.10.19 um 08:48 schrieb Johannes Schindelin via GitGitGadget:

> We have just introduced the helper `index_pos_to_insert_pos()` to help
> avoiding underflows when returning `-1 - pos` for cases where we want to
> return an insert position, using the ones' complement (as `int`).

We do not want to have it for *all* cases, where we return -1 - pos, but only for those cases, where the result was actually encoded by index_pos_to_insert_pos(). That excludes all cases where the argument is derived from index_name_pos(), and leaves just...

Show 8 quoted lines

> --- a/rerere.c
> +++ b/rerere.c
> @@ -154,7 +154,7 @@ static struct rerere_dir *find_rerere_dir(const char *hex)
>  		rr_dir->status = NULL;
>  		rr_dir->status_nr = 0;
>  		rr_dir->status_alloc = 0;
> -		pos = -1 - pos;
> +		pos = insert_pos_to_index_pos(pos);

... this one...

Show 13 quoted lines

>  
>  		/* Make sure the array is big enough ... */
>  		ALLOC_GROW(rerere_dir, rerere_dir_nr + 1, rerere_dir_alloc);
> diff --git a/sha1-name.c b/sha1-name.c
> index 49855ad24f..bee7ce39ee 100644
> --- a/sha1-name.c
> +++ b/sha1-name.c
> @@ -98,7 +98,7 @@ static void find_short_object_filename(struct disambiguate_state *ds)
>  		loose_objects = odb_loose_cache(odb, &ds->bin_pfx);
>  		pos = oid_array_lookup(loose_objects, &ds->bin_pfx);
>  		if (pos < 0)
> -			pos = -1 - pos;
> +			pos = insert_pos_to_index_pos(pos);

... and this one.

>  		while (!ds->ambiguous && pos < loose_objects->nr) {
>  			const struct object_id *oid;
>  			oid = loose_objects->oid + pos;

-- Hannes