string_list: add a new function, filter_string_list()

This function allows entries that don't match a specified criterion to
be discarded from a string_list while preserving the order of the
remaining entries.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/string-list.h b/string-list.h
index dc5fbc8..7d18e62 100644
--- a/string-list.h
+++ b/string-list.h
@@ -29,6 +29,15 @@ int for_each_string_list(struct string_list *list,
 #define for_each_string_list_item(item,list) \
 	for (item = (list)->items; item < (list)->items + (list)->nr; ++item)
 
+/*
+ * Apply want to each item in list, retaining only the ones for which
+ * the function returns true.  If free_util is true, call free() on
+ * the util members of any items that have to be deleted.  Preserve
+ * the order of the items that are retained.
+ */
+void filter_string_list(struct string_list *list, int free_util,
+			string_list_each_func_t want, void *cb_data);
+
 
 /* Use these functions only on sorted lists: */
 int string_list_has_string(const struct string_list *list, const char *string);