builtin/gc: make too_many_loose_objects() reusable without GC config

To decide whether or not a repository needs to be repacked we estimate
the number of loose objects. If the number exceeds a certain threshold
we perform the repack, otherwise we don't.

This is done via `too_many_loose_objects()`, which takes as parameter
the `struct gc_config`. This configuration is only used to determine the
threshold. In a subsequent commit we'll add another caller of this
function that wants to pass a different limit than the one stored in
that structure.

Refactor the function accordingly so that we only take the limit as
parameter instead of the whole structure.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Acked-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

builtin/gc.c

@@ -447,7 +447,7 @@ static int rerere_gc_condition(struct gc_config *cfg UNUSED)
 	return should_gc;
 }
 
-static int too_many_loose_objects(struct gc_config *cfg)
+static int too_many_loose_objects(int limit)
 {
 	/*
 	 * Quickly check if a "gc" is needed, by estimating how
@@ -469,7 +469,7 @@ static int too_many_loose_objects(struct gc_config *cfg)
 	if (!dir)
 		return 0;
 
-	auto_threshold = DIV_ROUND_UP(cfg->gc_auto_threshold, 256);
+	auto_threshold = DIV_ROUND_UP(limit, 256);
 	while ((ent = readdir(dir)) != NULL) {
 		if (strspn(ent->d_name, "0123456789abcdef") != hexsz_loose ||
 		    ent->d_name[hexsz_loose] != '\0')
@@ -703,7 +703,7 @@ static int need_to_gc(struct gc_config *cfg, struct strvec *repack_args)
 
 		add_repack_all_option(cfg, &keep_pack, repack_args);
 		string_list_clear(&keep_pack, 0);
-	} else if (too_many_loose_objects(cfg))
+	} else if (too_many_loose_objects(cfg->gc_auto_threshold))
 		add_repack_incremental_option(repack_args);
 	else
 		return 0;
@@ -1057,7 +1057,7 @@ int cmd_gc(int argc,
 					     !opts.quiet && !daemonized ? COMMIT_GRAPH_WRITE_PROGRESS : 0,
 					     NULL);
 
-	if (opts.auto_flag && too_many_loose_objects(&cfg))
+	if (opts.auto_flag && too_many_loose_objects(cfg.gc_auto_threshold))
 		warning(_("There are too many unreachable loose objects; "
 			"run 'git prune' to remove them."));