From 57e2d5775d9571506773ec135662c6c788103669 Mon Sep 17 00:00:00 2001
From: Sebastian Harl <sh@tokkee.org>
Date: Fri, 25 Oct 2013 17:23:32 +0200
Subject: [PATCH] utils llist: Added sdb_llist_iter_remove_current().

This function may be used to remove the current (the one returned by the last
sdb_llist_iter_get_next() call) iterator value from the list.

Note, that this function is not safe if another iterator is used in parallel
at the same time.
---
 src/include/utils/llist.h | 17 ++++++++++++++++-
 src/utils/llist.c         | 24 ++++++++++++++++++++++++
 t/utils/llist_test.c      | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/src/include/utils/llist.h b/src/include/utils/llist.h
index 104c9e4..2742139 100644
--- a/src/include/utils/llist.h
+++ b/src/include/utils/llist.h
@@ -173,7 +173,8 @@ sdb_llist_remove(sdb_llist_t *list,
 sdb_object_t *
 sdb_llist_shift(sdb_llist_t *list);
 
-/* sdb_llist_get_iter, sdb_llist_iter_has_next, sdb_llist_iter_get_next:
+/*
+ * sdb_llist_get_iter, sdb_llist_iter_has_next, sdb_llist_iter_get_next:
  * Iterate through the list, element by element.
  *
  * sdb_llist_iter_get_next returns NULL if there is no next element.
@@ -188,6 +189,20 @@ sdb_llist_iter_has_next(sdb_llist_iter_t *iter);
 sdb_object_t *
 sdb_llist_iter_get_next(sdb_llist_iter_t *iter);
 
+/*
+ * sdb_llist_iter_remove_current:
+ * Remove the current object from the list, that is, the object which was
+ * returned by the last call to sdb_llist_iter_get_next().
+ *
+ * This operation is not safe if another iterator is in use at the same time.
+ *
+ * Returns:
+ *  - 0 on success
+ *  - a negative value else
+ */
+int
+sdb_llist_iter_remove_current(sdb_llist_iter_t *iter);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
diff --git a/src/utils/llist.c b/src/utils/llist.c
index 0af9c8c..0a4665d 100644
--- a/src/utils/llist.c
+++ b/src/utils/llist.c
@@ -434,5 +434,29 @@ sdb_llist_iter_get_next(sdb_llist_iter_t *iter)
 	return obj;
 } /* sdb_llist_iter_get_next */
 
+int
+sdb_llist_iter_remove_current(sdb_llist_iter_t *iter)
+{
+	sdb_llist_elem_t *elem;
+
+	if ((! iter) || (! iter->list))
+		return -1;
+
+	pthread_rwlock_wrlock(&iter->list->lock);
+
+	if (! iter->elem) /* reached end of list */
+		elem = iter->list->tail;
+	else
+		elem = iter->elem->prev;
+	if (elem)
+		sdb_llist_remove_elem(iter->list, elem);
+
+	pthread_rwlock_unlock(&iter->list->lock);
+
+	if (! elem)
+		return -1;
+	return 0;
+} /* sdb_llist_iter_remove */
+
 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 
diff --git a/t/utils/llist_test.c b/t/utils/llist_test.c
index 638d2fb..ede8200 100644
--- a/t/utils/llist_test.c
+++ b/t/utils/llist_test.c
@@ -233,6 +233,41 @@ START_TEST(test_sdb_llist_iter)
 }
 END_TEST
 
+START_TEST(test_sdb_llist_iter_remove)
+{
+	sdb_llist_iter_t *iter;
+	sdb_object_t *check;
+	size_t i;
+
+	populate();
+
+	iter = sdb_llist_get_iter(list);
+	fail_unless(iter != NULL,
+			"sdb_llist_get_iter() did not return an iterator");
+
+	i = 0;
+	while (sdb_llist_iter_has_next(iter)) {
+		check = sdb_llist_iter_get_next(iter);
+		fail_unless(check == &golden_data[i],
+				"sdb_llist_iter_get_next() = %p; expected: %p",
+				check, &golden_data[i]);
+
+		sdb_llist_iter_remove_current(iter);
+		++i;
+	}
+	sdb_llist_iter_destroy(iter);
+
+	fail_unless(i == (size_t)SDB_STATIC_ARRAY_LEN(golden_data),
+			"iterated for %zu steps; expected: %i",
+			i, SDB_STATIC_ARRAY_LEN(golden_data));
+
+	/* all elements should be removed */
+	check = sdb_llist_shift(list);
+	fail_unless(check == NULL,
+			"sdb_llist_shift() = %p; expected: NULL", check);
+}
+END_TEST
+
 Suite *
 util_llist_suite(void)
 {
@@ -249,6 +284,7 @@ util_llist_suite(void)
 	tcase_add_test(tc, test_sdb_llist_search);
 	tcase_add_test(tc, test_sdb_llist_shift);
 	tcase_add_test(tc, test_sdb_llist_iter);
+	tcase_add_test(tc, test_sdb_llist_iter_remove);
 	suite_add_tcase(s, tc);
 
 	return s;
-- 
2.30.2