[list] Add list_for_each_entry_safe_continue()

Signed-off-by: Michael Brown <mcb30@ipxe.org>

2 files changed, 48 insertions, 0 deletions

diff --git a/src/include/ipxe/list.h b/src/include/ipxe/list.h
index 53edfc9f..2f02e71f 100644
--- a/src/include/ipxe/list.h
+++ b/src/include/ipxe/list.h
@@ -490,6 +490,22 @@ extern void extern_list_splice_tail_init ( struct list_head *list,
 	      pos = list_entry ( pos->member.prev, typeof ( *pos ), member ) )
 
 /**
+ * Iterate over subsequent entries in a list, safe against deletion
+ *
+ * @v pos		Iterator
+ * @v tmp		Temporary value (of same type as iterator)
+ * @v head		List head
+ * @v member		Name of list field within iterator's type
+ */
+#define list_for_each_entry_safe_continue( pos, tmp, head, member )	      \
+	for ( list_check ( (head) ),					      \
+	      pos = list_entry ( pos->member.next, typeof ( *pos ), member ), \
+	      tmp = list_entry ( pos->member.next, typeof ( *tmp ), member ); \
+	      &pos->member != (head);					      \
+	      pos = tmp,						      \
+	      tmp = list_entry ( tmp->member.next, typeof ( *tmp ), member ) )
+
+/**
  * Test if list contains a specified entry
  *
  * @v entry		Entry
diff --git a/src/tests/list_test.c b/src/tests/list_test.c
index f18c63f2..c24e8082 100644
--- a/src/tests/list_test.c
+++ b/src/tests/list_test.c
@@ -518,6 +518,38 @@ static void list_test_exec ( void ) {
 	list_iterate_entry_ok ( list_for_each_entry_continue_reverse, "",
 				pos, list, list );
 
+	/* Test list_for_each_entry_safe_continue() */
+	INIT_LIST_HEAD ( list );
+	list_add_tail ( &list_tests[9].list, list );
+	list_add_tail ( &list_tests[4].list, list );
+	list_add_tail ( &list_tests[2].list, list );
+	list_add_tail ( &list_tests[5].list, list );
+	list_add_tail ( &list_tests[7].list, list );
+	{
+		char *expecteds[] = { "94257", "9457", "947", "94" };
+		char **expected = expecteds;
+		pos = &list_tests[4];
+		list_for_each_entry_safe_continue ( pos, tmp, list, list ) {
+			list_contents_ok ( list, *expected );
+			list_del ( &pos->list );
+			expected++;
+			list_contents_ok ( list, *expected );
+		}
+	}
+	list_contents_ok ( list, "94" );
+	{
+		char *expecteds[] = { "94", "4", "" };
+		char **expected = expecteds;
+		ok ( pos == list_entry ( list, struct list_test, list ) );
+		list_for_each_entry_safe_continue ( pos, tmp, list, list ) {
+			list_contents_ok ( list, *expected );
+			list_del ( &pos->list );
+			expected++;
+			list_contents_ok ( list, *expected );
+		}
+	}
+	ok ( list_empty ( list ) );
+
 	/* Test list_contains() and list_contains_entry() */
 	INIT_LIST_HEAD ( list );
 	INIT_LIST_HEAD ( &list_tests[3].list );