# HG changeset patch
# User Chris Seaton <chris.seaton@oracle.com>
# Date 1379073760 -3600
# Node ID ccf047a30f18fb08f2d8d74edb602e041d94fef4
# Parent  46e7087387173de2abe10400232ed62e4750fe91
Truffle: NodeUtil.getNthParent.

diff -r 46e708738717 -r ccf047a30f18 graal/com.oracle.truffle.api/src/com/oracle/truffle/api/nodes/NodeUtil.java
--- a/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/nodes/NodeUtil.java	Fri Sep 13 11:57:18 2013 +0200
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/nodes/NodeUtil.java	Fri Sep 13 13:02:40 2013 +0100
@@ -423,6 +423,24 @@
         return result;
     }
 
+    /**
+     * Get the nth parent of a node, where the 0th parent is the node itself. Returns null if there
+     * are less than n ancestors.
+     */
+    public static Node getNthParent(Node node, int n) {
+        Node parent = node;
+
+        for (int i = 0; i < n; i++) {
+            parent = parent.getParent();
+
+            if (parent == null) {
+                return null;
+            }
+        }
+
+        return parent;
+    }
+
     /** find annotation in class/interface hierarchy. */
     public static <T extends Annotation> T findAnnotation(Class<?> clazz, Class<T> annotationClass) {
         if (clazz.getAnnotation(annotationClass) != null) {