ls-files: convert prune_cache to take an index

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/ls-files.c

@@ -380,30 +380,31 @@ static void show_files(struct dir_struct *dir)
 /*
  * Prune the index to only contain stuff starting with "prefix"
  */
-static void prune_cache(const char *prefix, size_t prefixlen)
+static void prune_index(struct index_state *istate,
+			const char *prefix, size_t prefixlen)
 {
 	int pos;
 	unsigned int first, last;
 
 	if (!prefix)
 		return;
-	pos = cache_name_pos(prefix, prefixlen);
+	pos = index_name_pos(istate, prefix, prefixlen);
 	if (pos < 0)
 		pos = -pos-1;
 	first = pos;
-	last = active_nr;
+	last = istate->cache_nr;
 	while (last > first) {
 		int next = (last + first) >> 1;
-		const struct cache_entry *ce = active_cache[next];
+		const struct cache_entry *ce = istate->cache[next];
 		if (!strncmp(ce->name, prefix, prefixlen)) {
 			first = next+1;
 			continue;
 		}
 		last = next;
 	}
-	memmove(active_cache, active_cache + pos,
+	memmove(istate->cache, istate->cache + pos,
 		(last - pos) * sizeof(struct cache_entry *));
-	active_nr = last - pos;
+	istate->cache_nr = last - pos;
 }
 
 static int get_common_prefix_len(const char *common_prefix)
@@ -661,7 +662,7 @@ int cmd_ls_files(int argc, const char **argv, const char *cmd_prefix)
 		max_prefix = common_prefix(&pathspec);
 	max_prefix_len = get_common_prefix_len(max_prefix);
 
-	prune_cache(max_prefix, max_prefix_len);
+	prune_index(&the_index, max_prefix, max_prefix_len);
 
 	/* Treat unmatching pathspec elements as errors */
 	if (pathspec.nr && error_unmatch)