string-list: return index directly when inserting an existing element

When inserting an existing element, "add_entry" would convert "index"
value to "-1-index" to indicate the caller that this element is in the
list already.

However, in "string_list_insert", we would simply convert this to the
original positive index without any further action. Let's directly
return the index as we don't care about whether the element is in the
list by using "add_entry".

In the future, if we want to let "add_entry" tell the caller, we may add
"int *exact_match" parameter to "add_entry" instead of converting the
index to negative to indicate.

Signed-off-by: shejialuo <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: shejialuo

string-list.c

@@ -40,14 +40,13 @@ static int get_entry_index(const struct string_list *list, const char *string,
 	return right;
 }
 
-/* returns -1-index if already exists */
 static int add_entry(struct string_list *list, const char *string)
 {
 	int exact_match = 0;
 	int index = get_entry_index(list, string, &exact_match);
 
 	if (exact_match)
-		return -1 - index;
+		return index;
 
 	ALLOC_GROW(list->items, list->nr+1, list->alloc);
 	if (index < list->nr)
@@ -65,9 +64,6 @@ struct string_list_item *string_list_insert(struct string_list *list, const char
 {
 	int index = add_entry(list, string);
 
-	if (index < 0)
-		index = -1 - index;
-
 	return list->items + index;
 }