string-list: add string_list_remove function

Teach string-list to be able to remove a string from a sorted
'struct string_list'.

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

string-list.c

@@ -67,6 +67,24 @@ struct string_list_item *string_list_insert(struct string_list *list, const char
 	return list->items + index;
 }
 
+void string_list_remove(struct string_list *list, const char *string,
+			int free_util)
+{
+	int exact_match;
+	int i = get_entry_index(list, string, &exact_match);
+
+	if (exact_match) {
+		if (list->strdup_strings)
+			free(list->items[i].string);
+		if (free_util)
+			free(list->items[i].util);
+
+		list->nr--;
+		memmove(list->items + i, list->items + i + 1,
+			(list->nr - i) * sizeof(struct string_list_item));
+	}
+}
+
 int string_list_has_string(const struct string_list *list, const char *string)
 {
 	int exact_match;

string-list.h

@@ -62,6 +62,13 @@ int string_list_find_insert_index(const struct string_list *list, const char *st
  */
 struct string_list_item *string_list_insert(struct string_list *list, const char *string);
 
+/*
+ * Removes the given string from the sorted list.
+ * If the string doesn't exist, the list is not altered.
+ */
+extern void string_list_remove(struct string_list *list, const char *string,
+			       int free_util);
+
 /*
  * Checks if the given string is part of a sorted list. If it is part of the list,
  * return the coresponding string_list_item, NULL otherwise.