Subject: Re: [PATCH 3/7] release_delta_base_cache: reuse existing detach function

From: Junio C Hamano <[email-masked]>
Date: Tue, 23 Aug 2016 14:49:15 -0700

Jeff King <[email-masked]> writes:

> This function drops an entry entirely from the cache,
> meaning that aside from the freeing of the buffer, it is
> exactly equivalent to detach_delta_base_cache_entry(). Let's
> build on top of the detach function, which shortens the code
> and will make it simpler when we change out the underlying
> storage in future patches.
>
> Signed-off-by: Jeff King <[email-masked]>
> ---
>  sha1_file.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/sha1_file.c b/sha1_file.c
> index 1d0810c..8264b39 100644
> --- a/sha1_file.c
> +++ b/sha1_file.c
> @@ -2152,10 +2152,7 @@ static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
>  {
>  	if (ent->data) {
>  		free(ent->data);
> -		ent->data = NULL;
> -		ent->lru.next->prev = ent->lru.prev;
> -		ent->lru.prev->next = ent->lru.next;
> -		delta_base_cached -= ent->size;
> +		detach_delta_base_cache_entry(ent);

If we were designing this from scratch, we might have made detach_*
to return the pointer to minimize direct access to ent->data, but I
do not think it is worth it.  Looks very sensible.