Subject: Re: [PATCH 3/3] ref-filter: factor ref_array pushing into its own function

From: Derrick Stolee <[email-masked]>
Date: Fri, 6 Apr 2018 15:27:13 -0400

On 4/6/2018 2:59 PM, Jeff King wrote:
> In preparation for callers constructing their own ref_array
> structs, let's move our own internal push operation into its
> own function.
>
> While we're at it, we can replace REALLOC_ARRAY() with
> ALLOC_GROW(), which should give the growth operation
> amortized linear complexity (as opposed to growing by one,
> which is potentially quadratic, though in-place realloc
> growth often makes this faster in practice).
>
> Signed-off-by: Jeff King <[email-masked]>
> ---
>   ref-filter.c | 16 +++++++++++++---
>   ref-filter.h |  8 ++++++++
>   2 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/ref-filter.c b/ref-filter.c
> index c1c3cc9480..6e9328b274 100644
> --- a/ref-filter.c
> +++ b/ref-filter.c
> @@ -1840,6 +1840,18 @@ static struct ref_array_item *new_ref_array_item(const char *refname,
>   	return ref;
>   }
>   
> +struct ref_array_item *ref_array_push(struct ref_array *array,
> +				      const char *refname,
> +				      const struct object_id *oid)
> +{
> +	struct ref_array_item *ref = new_ref_array_item(refname, oid);
> +
> +	ALLOC_GROW(array->items, array->nr + 1, array->alloc);
> +	array->items[array->nr++] = ref;
> +
> +	return ref;
> +}
> +
>   static int ref_kind_from_refname(const char *refname)
>   {
>   	unsigned int i;
> @@ -1930,13 +1942,11 @@ static int ref_filter_handler(const char *refname, const struct object_id *oid,
>   	 * to do its job and the resulting list may yet to be pruned
>   	 * by maxcount logic.
>   	 */
> -	ref = new_ref_array_item(refname, oid);
> +	ref = ref_array_push(ref_cbdata->array, refname, oid);
>   	ref->commit = commit;
>   	ref->flag = flag;
>   	ref->kind = kind;
>   
> -	REALLOC_ARRAY(ref_cbdata->array->items, ref_cbdata->array->nr + 1);
> -	ref_cbdata->array->items[ref_cbdata->array->nr++] = ref;
>   	return 0;
>   }
>   
> diff --git a/ref-filter.h b/ref-filter.h
> index 68268f9ebc..76cf87cb6c 100644
> --- a/ref-filter.h
> +++ b/ref-filter.h
> @@ -135,4 +135,12 @@ void setup_ref_filter_porcelain_msg(void);
>   void pretty_print_ref(const char *name, const struct object_id *oid,
>   		      const struct ref_format *format);
>   
> +/*
> + * Push a single ref onto the array; this can be used to construct your own
> + * ref_array without using filter_refs().
> + */
> +struct ref_array_item *ref_array_push(struct ref_array *array,
> +				      const char *refname,
> +				      const struct object_id *oid);
> +
>   #endif /*  REF_FILTER_H  */

The three patches in this series look good to me.

Reviewed-by: Derrick Stolee <[email-masked]>