Add find_insert_index, insert_at_index and clear_func functions to string_list

string_list_find_insert_index() and string_list_insert_at_index()
enables you to see if an item is in the string_list, and to
insert at the appropriate index in the list, if not there.
This is usefull if you need to manipulate an existing item,
if present, and insert a new item if not.

Future mailmap code will use this construct to enable
complex (old_name, old_email) -> (new_name, new_email)
lookups.

The string_list_clear_func() allows to call a custom
cleanup function on each item in a string_list, which is
useful is the util member points to a complex structure.

Signed-off-by: Marius Storm-Olsen <marius@trolltech.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 48 insertions, 4 deletions

diff --git a/string-list.c b/string-list.c
index ddd83c8c76..15e14cf47a 100644
--- a/string-list.c
+++ b/string-list.c
@@ -26,10 +26,10 @@ static int get_entry_index(const struct string_list *list, const char *string,
 }
 
 /* returns -1-index if already exists */
-static int add_entry(struct string_list *list, const char *string)
+static int add_entry(int insert_at, struct string_list *list, const char *string)
 {
-	int exact_match;
-	int index = get_entry_index(list, string, &exact_match);
+	int exact_match = 0;
+	int index = insert_at != -1 ? insert_at : get_entry_index(list, string, &exact_match);
 
 	if (exact_match)
 		return -1 - index;
@@ -53,7 +53,13 @@ static int add_entry(struct string_list *list, const char *string)
 
 struct string_list_item *string_list_insert(const char *string, struct string_list *list)
 {
-	int index = add_entry(list, string);
+	return string_list_insert_at_index(-1, string, list);
+}
+
+struct string_list_item *string_list_insert_at_index(int insert_at,
+						     const char *string, struct string_list *list)
+{
+	int index = add_entry(insert_at, list, string);
 
 	if (index < 0)
 		index = -1 - index;
@@ -68,6 +74,16 @@ int string_list_has_string(const struct string_list *list, const char *string)
 	return exact_match;
 }
 
+int string_list_find_insert_index(const struct string_list *list, const char *string,
+				  int negative_existing_index)
+{
+	int exact_match;
+	int index = get_entry_index(list, string, &exact_match);
+	if (exact_match)
+		index = -1 - (negative_existing_index ? index : 0);
+	return index;
+}
+
 struct string_list_item *string_list_lookup(const char *string, struct string_list *list)
 {
 	int exact_match, i = get_entry_index(list, string, &exact_match);
@@ -94,6 +110,25 @@ void string_list_clear(struct string_list *list, int free_util)
 	list->nr = list->alloc = 0;
 }
 
+void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc)
+{
+	if (list->items) {
+		int i;
+		if (clearfunc) {
+			for (i = 0; i < list->nr; i++)
+				clearfunc(list->items[i].util, list->items[i].string);
+		}
+		if (list->strdup_strings) {
+			for (i = 0; i < list->nr; i++)
+				free(list->items[i].string);
+		}
+		free(list->items);
+	}
+	list->items = NULL;
+	list->nr = list->alloc = 0;
+}
+
+
 void print_string_list(const char *text, const struct string_list *p)
 {
 	int i;
diff --git a/string-list.h b/string-list.h
index 4d6a7051fe..d32ba05202 100644
--- a/string-list.h
+++ b/string-list.h
@@ -15,9 +15,18 @@ struct string_list
 void print_string_list(const char *text, const struct string_list *p);
 void string_list_clear(struct string_list *list, int free_util);
 
+/* Use this function to call a custom clear function on each util pointer */
+/* The string associated with the util pointer is passed as the second argument */
+typedef void (*string_list_clear_func_t)(void *p, const char *str);
+void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc);
+
 /* Use these functions only on sorted lists: */
 int string_list_has_string(const struct string_list *list, const char *string);
+int string_list_find_insert_index(const struct string_list *list, const char *string,
+				  int negative_existing_index);
 struct string_list_item *string_list_insert(const char *string, struct string_list *list);
+struct string_list_item *string_list_insert_at_index(int insert_at,
+						     const char *string, struct string_list *list);
 struct string_list_item *string_list_lookup(const char *string, struct string_list *list);
 
 /* Use these functions only on unsorted lists: */