[Mesa-dev] [PATCH 08/14] util: rb_tree: add safe iterators

[Lionel Landwerlin]

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
---
 src/util/rb_tree.h | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/src/util/rb_tree.h b/src/util/rb_tree.h
index c77e9255ea2..df1a4197b8a 100644
--- a/src/util/rb_tree.h
+++ b/src/util/rb_tree.h
@@ -243,6 +243,24 @@ struct rb_node *rb_node_prev(struct rb_node *node);
         &node->field != NULL; \
         node = rb_node_data(type, rb_node_next(&node->field), field))
 
+/** Iterate over the nodes in the tree, allowing the current node to be freed
+ *
+ * \param   type    The type of the containing data structure
+ *
+ * \param   node    The variable name for current node in the iteration;
+ *                  this will be declared as a pointer to \p type
+ *
+ * \param   T       The red-black tree
+ *
+ * \param   field   The rb_node field in containing data structure
+ */
+#define rb_tree_foreach_safe(type, node, T, field) \
+   for (type *node = rb_node_data(type, rb_tree_first(T), field), \
+           *_next = (&node->field != NULL) ? rb_node_data(type, rb_node_next(&node->field), field) : node; \
+        &node->field != NULL; \
+        node = _next, \
+           _next = (&_next->field != NULL) ? rb_node_data(type, rb_node_next(&_next->field), field) : _next)
+
 /** Iterate over the nodes in the tree in reverse
  *
  * \param   type    The type of the containing data structure
@@ -259,6 +277,24 @@ struct rb_node *rb_node_prev(struct rb_node *node);
         &node->field != NULL; \
         node = rb_node_data(type, rb_node_prev(&node->field), field))
 
+/** Iterate over the nodes in the tree in reverse, allowing the current node to be freed
+ *
+ * \param   type    The type of the containing data structure
+ *
+ * \param   node    The variable name for current node in the iteration;
+ *                  this will be declared as a pointer to \p type
+ *
+ * \param   T       The red-black tree
+ *
+ * \param   field   The rb_node field in containing data structure
+ */
+#define rb_tree_foreach_rev_safe(type, node, T, field) \
+   for (type *node = rb_node_data(type, rb_tree_last(T), field), \
+           *_prev = rb_node_prev(&node->field) ? rb_node_data(type, rb_node_prev(&node->field), field) : NULL; \
+        &node->field != NULL; \
+        node = _prev, \
+           _prev = (prev && rb_node_prev(&_prev->field)) ? rb_node_data(type, rb_node_prev(&_prev->field), field) : NULL)
+
 /** Validate a red-black tree
  *
  * This function walks the tree and validates that this is a valid red-
-- 
2.18.0