object_array: add function object_array_filter()

Add a function that allows unwanted entries in an object_array to be
removed.  This encapsulation is a step towards giving object_array
ownership of its entries' name memory.

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

1 files changed, 16 insertions, 0 deletions

diff --git a/object.c b/object.c
index 20703f52ed..fcd4a82c13 100644
--- a/object.c
+++ b/object.c
@@ -278,6 +278,22 @@ void add_object_array_with_mode(struct object *obj, const char *name, struct obj
 	array->nr = ++nr;
 }
 
+void object_array_filter(struct object_array *array,
+			 object_array_each_func_t want, void *cb_data)
+{
+	unsigned nr = array->nr, src, dst;
+	struct object_array_entry *objects = array->objects;
+
+	for (src = dst = 0; src < nr; src++) {
+		if (want(&objects[src], cb_data)) {
+			if (src != dst)
+				objects[dst] = objects[src];
+			dst++;
+		}
+	}
+	array->nr = dst;
+}
+
 void object_array_remove_duplicates(struct object_array *array)
 {
 	unsigned int ref, src, dst;