Subject: Re: [PATCH 05/17] cmd_diff(): use an object_array for holding trees

From: Junio C Hamano <[email-masked]>
Date: Tue, 21 May 2013 10:30:50 -0700

Michael Haggerty <[email-masked]> writes:

> Change cmd_diff() to use a (struct object_array) for holding the trees
> that it accumulates, rather than rolling its own equivalent.
>

A significant detail missing here is that this lifts the hardcoded
100 tree limit in combined diff but that does not matter in
practice, I would suppose ;-).

> Signed-off-by: Michael Haggerty <[email-masked]>
> ---
>  builtin/diff.c | 37 ++++++++++++++++++-------------------
>  1 file changed, 18 insertions(+), 19 deletions(-)
>
> diff --git a/builtin/diff.c b/builtin/diff.c
> index ba68c6c..72d99c0 100644
> --- a/builtin/diff.c
> +++ b/builtin/diff.c
> @@ -252,8 +252,8 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
>  {
>  	int i;
>  	struct rev_info rev;
> -	struct object_array_entry ent[100];
> -	int ents = 0, blobs = 0, paths = 0;
> +	struct object_array ent = OBJECT_ARRAY_INIT;
> +	int blobs = 0, paths = 0;
>  	const char *path = NULL;
>  	struct blobinfo blob[2];
>  	int nongit;
> @@ -350,13 +350,8 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
>  		if (obj->type == OBJ_COMMIT)
>  			obj = &((struct commit *)obj)->tree->object;
>  		if (obj->type == OBJ_TREE) {
> -			if (ARRAY_SIZE(ent) <= ents)
> -				die(_("more than %d trees given: '%s'"),
> -				    (int) ARRAY_SIZE(ent), name);
>  			obj->flags |= flags;
> -			ent[ents].item = obj;
> -			ent[ents].name = name;
> -			ents++;
> +			add_object_array(obj, name, &ent);
>  			continue;
>  		}
>  		if (obj->type == OBJ_BLOB) {
> @@ -380,7 +375,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
>  	/*
>  	 * Now, do the arguments look reasonable?
>  	 */
> -	if (!ents) {
> +	if (!ent.nr) {
>  		switch (blobs) {
>  		case 0:
>  			result = builtin_diff_files(&rev, argc, argv);
> @@ -401,22 +396,26 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
>  	}
>  	else if (blobs)
>  		usage(builtin_diff_usage);
> -	else if (ents == 1)
> +	else if (ent.nr == 1)
>  		result = builtin_diff_index(&rev, argc, argv);
> -	else if (ents == 2)
> -		result = builtin_diff_tree(&rev, argc, argv, &ent[0], &ent[1]);
> -	else if (ent[0].item->flags & UNINTERESTING) {
> +	else if (ent.nr == 2)
> +		result = builtin_diff_tree(&rev, argc, argv,
> +					   &ent.objects[0], &ent.objects[1]);
> +	else if (ent.objects[0].item->flags & UNINTERESTING) {
>  		/*
>  		 * diff A...B where there is at least one merge base
> -		 * between A and B.  We have ent[0] == merge-base,
> -		 * ent[ents-2] == A, and ent[ents-1] == B.  Show diff
> -		 * between the base and B.  Note that we pick one
> -		 * merge base at random if there are more than one.
> +		 * between A and B.  We have ent.objects[0] ==
> +		 * merge-base, ent.objects[ents-2] == A, and
> +		 * ent.objects[ents-1] == B.  Show diff between the
> +		 * base and B.  Note that we pick one merge base at
> +		 * random if there are more than one.
>  		 */
> -		result = builtin_diff_tree(&rev, argc, argv, &ent[0], &ent[ents-1]);
> +		result = builtin_diff_tree(&rev, argc, argv,
> +					   &ent.objects[0],
> +					   &ent.objects[ent.nr-1]);
>  	} else
>  		result = builtin_diff_combined(&rev, argc, argv,
> -					       ent, ents);
> +					       ent.objects, ent.nr);
>  	result = diff_result_code(&rev.diffopt, result);
>  	if (1 < rev.diffopt.skip_stat_unmatch)
>  		refresh_index_quietly();