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.

In 8fd2cb4 (Extract helper bits from c-merge-recursive work,
2006-07-25), we create "path-list.c" and then introduce above code path.

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;
 }