utils llist: Added sdb_llist_clear().

This function clears the list by removing all elements and releasing the
included objects. It's similar to destroy() but does not actually release the
list object itself.

diff --git a/src/include/utils/llist.h b/src/include/utils/llist.h
index f557c9d41c63800ead40925f1414b7da02d80334..28816a6a49abaaf58232f55ab5b7e9a9f6a2ffa8 100644 (file)
--- a/src/include/utils/llist.h
+++ b/src/include/utils/llist.h
@@ -56,6 +56,14 @@ sdb_llist_create(void);
 void
 sdb_llist_destroy(sdb_llist_t *list);
 
+/*
+ * sdb_llist_clear:
+ * Remove all elements from the list, releasing the included objects
+ * (decrement the ref-count).
+ */
+void
+sdb_llist_clear(sdb_llist_t *list);
+
 /*
  * sdb_llist_clone:
  * Clone an existing list. The objects stored in the list will not be copied

diff --git a/src/utils/llist.c b/src/utils/llist.c
index e042c99df1c81bb3b55482f8a6b8b5470a20d388..f9bf722785dab30087c2c6e796858f3decd3f4a7 100644 (file)
--- a/src/utils/llist.c
+++ b/src/utils/llist.c
@@ -69,6 +69,26 @@ struct sdb_llist_iter {
  * private helper functions
  */
 
+static void
+llist_clear(sdb_llist_t *list)
+{
+       sdb_llist_elem_t *elem;
+
+       assert(list);
+       elem = list->head;
+       while (elem) {
+               sdb_llist_elem_t *tmp = elem->next;
+
+               sdb_object_deref(elem->obj);
+               free(elem);
+
+               elem = tmp;
+       }
+
+       list->head = list->tail = NULL;
+       list->length = 0;
+} /* llist_clear */
+
 /* Insert a new element after 'elem'. If 'elem' is NULL, insert at the head of
  * the list. */
 static int
@@ -213,31 +233,27 @@ sdb_llist_clone(sdb_llist_t *list)
 void
 sdb_llist_destroy(sdb_llist_t *list)
 {
-       sdb_llist_elem_t *elem;
-
        if (! list)
                return;
 
        pthread_rwlock_wrlock(&list->lock);
-
-       elem = list->head;
-       while (elem) {
-               sdb_llist_elem_t *tmp = elem->next;
-
-               sdb_object_deref(elem->obj);
-               free(elem);
-
-               elem = tmp;
-       }
-
-       list->head = list->tail = NULL;
-       list->length = 0;
-
+       llist_clear(list);
        pthread_rwlock_unlock(&list->lock);
        pthread_rwlock_destroy(&list->lock);
        free(list);
 } /* sdb_llist_destroy */
 
+void
+sdb_llist_clear(sdb_llist_t *list)
+{
+       if (! list)
+               return;
+
+       pthread_rwlock_wrlock(&list->lock);
+       llist_clear(list);
+       pthread_rwlock_unlock(&list->lock);
+} /* sdb_llist_clear */
+
 int
 sdb_llist_append(sdb_llist_t *list, sdb_object_t *obj)
 {

diff --git a/t/utils/llist_test.c b/t/utils/llist_test.c
index e8d366c2f103ccb244775c78bec7d5c9d2167ad5..cc9954d98662c76f89ef32f4e9416ea178073017 100644 (file)
--- a/t/utils/llist_test.c
+++ b/t/utils/llist_test.c
@@ -115,6 +115,25 @@ START_TEST(test_destroy)
 }
 END_TEST
 
+START_TEST(test_clear)
+{
+       size_t i;
+       populate();
+       sdb_llist_clear(list);
+
+       for (i = 0; i < SDB_STATIC_ARRAY_LEN(golden_data); ++i) {
+               fail_unless(golden_data[i].ref_cnt == 1,
+                               "sdb_llist_clear() did not deref element %s",
+                               golden_data[i].name);
+       }
+
+       i = sdb_llist_len(list);
+       fail_unless(i == 0,
+                       "sdb_llist_clear() left %zu elements in the list; "
+                       "expected: 0", i);
+}
+END_TEST
+
 START_TEST(test_append)
 {
        size_t i;
@@ -361,6 +380,7 @@ util_llist_suite(void)
        tcase_add_checked_fixture(tc, setup, teardown);
        tcase_add_test(tc, test_clone);
        tcase_add_test(tc, test_destroy);
+       tcase_add_test(tc, test_clear);
        tcase_add_test(tc, test_append);
        tcase_add_test(tc, test_insert);
        tcase_add_test(tc, test_validate_insert);