From: Ondřej Surý <ondrej@isc.org>
Date: Thu, 19 Oct 2023 08:21:20 +0000 (+0200)
Subject: Add ISC_LIST_FOREACH_REV(_SAFE) macros
X-Git-Tag: v9.19.18~24^2~1
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d2e84a4b9713b85beaf5604ff67f3530c5a96a15;p=thirdparty%2Fbind9.git

Add ISC_LIST_FOREACH_REV(_SAFE) macros

Add complementary macros to ISC_LIST_FOREACH(_SAFE) that walk the lists
in reverse.

  * ISC_LIST_FOREACH_REV(list, elt, link) - walk the static list from
    tail to head
  * ISC_LIST_FOREACH_REV_SAFE(list, elt, link, next) - walk the list
    from tail to head in a manner that's safe against list member
    deletions
---

diff --git a/.clang-format b/.clang-format
index 124d82a2696..54a39fdb4d4 100644
--- a/.clang-format
+++ b/.clang-format
@@ -78,4 +78,4 @@ PenaltyBreakString: 80
 PenaltyExcessCharacter: 100
 Standard: Cpp11
 ContinuationIndentWidth: 8
-ForEachMacros: [ 'cds_lfs_for_each', 'cds_lfs_for_each_safe', 'cds_list_for_each_entry_safe', 'ISC_LIST_FOREACH', 'ISC_LIST_FOREACH_SAFE' ]
+ForEachMacros: [ 'cds_lfs_for_each', 'cds_lfs_for_each_safe', 'cds_list_for_each_entry_safe', 'ISC_LIST_FOREACH', 'ISC_LIST_FOREACH_SAFE', 'ISC_LIST_FOREACH_REV', 'ISC_LIST_FOREACH_REV_SAFE' ]
diff --git a/lib/isc/include/isc/list.h b/lib/isc/include/isc/list.h
index a168254d40b..67ed208c2c0 100644
--- a/lib/isc/include/isc/list.h
+++ b/lib/isc/include/isc/list.h
@@ -241,3 +241,17 @@
 	     elt != NULL;									\
 	     elt = next, next = (elt != NULL) ? ISC_LIST_NEXT(elt, link) : NULL)
 /* clang-format on */
+
+/* clang-format off */
+#define ISC_LIST_FOREACH_REV(list, elt, link)	\
+	for (elt = ISC_LIST_TAIL(list);		\
+	     elt != NULL;			\
+	     elt = ISC_LIST_PREV(elt, link))
+/* clang-format on */
+
+/* clang-format off */
+#define ISC_LIST_FOREACH_REV_SAFE(list, elt, link, prev)						\
+	for (elt = ISC_LIST_TAIL(list), prev = (elt != NULL) ? ISC_LIST_PREV(elt, link) : NULL;	\
+	     elt != NULL;									\
+	     elt = prev, prev = (elt != NULL) ? ISC_LIST_PREV(elt, link) : NULL)
+/* clang-format on */