Patch from Igor:

Replacing usage of ShallowNodeIterator to loop throw node children by
explicit calls to Node.getFirstChild()/ Node.getNextSibling()) with
comments when the node children list is modified while iterating
through it.

It avoids creation of ShallowNodeIterator objects and eliminates the
need to have ShallowNodeIterator class.

js/rhino/src/org/mozilla/javascript/IRFactory.java

@@ -577,12 +577,13 @@ public class IRFactory {
         Node temp = createNewTemp(result);
         result = temp;
 
-        java.util.Enumeration children = ((Node) obj).getChildIterator();
-
         Node elem = null;
         int i = 0;
-        while (children.hasMoreElements()) {
-            elem = (Node) children.nextElement();
+        for (Node cursor = ((Node) obj).getFirstChild(); cursor != null;) {
+            // Move cursor to cursor.next before elem.next can be 
+            // altered in new Node constructor
+            elem = cursor;
+            cursor = cursor.getNextSibling();
             if (elem.getType() == TokenStream.PRIMARY &&
                 elem.getInt() == TokenStream.UNDEFINED)
             {
@@ -640,16 +641,16 @@ public class IRFactory {
         Node temp = createNewTemp(result);
         result = temp;
 
-        java.util.Enumeration children = ((Node) obj).getChildIterator();
-
-        while (children.hasMoreElements()) {
-            Node elem = (Node)children.nextElement();
-
-            int op = (elem.getType() == TokenStream.NAME)
+        for (Node cursor = ((Node) obj).getFirstChild(); cursor != null;) {
+            Node n = cursor;
+            cursor = cursor.getNextSibling();
+            int op = (n.getType() == TokenStream.NAME)
                    ? TokenStream.SETPROP
                    : TokenStream.SETELEM;
-            Node addelem = new Node(op, createUseTemp(temp),
-                                    elem, (Node)children.nextElement());
+            // Move cursor before next.next can be altered in new Node
+            Node next = cursor;
+            cursor = cursor.getNextSibling();
+            Node addelem = new Node(op, createUseTemp(temp), n, next);
             result = new Node(TokenStream.COMMA, result, addelem);
         }
         return new Node(TokenStream.COMMA, result, createUseTemp(temp));
@@ -693,7 +694,7 @@ public class IRFactory {
             result.addChildToBack(ifNotTarget);
         }
 
-    	return result;
+        return result;
     }
 
     public Object createTernary(Object cond, Object ifTrue, Object ifFalse) {
@@ -728,7 +729,7 @@ public class IRFactory {
             }
             return new Node(nodeType, left, right);
         }
-    	return new Node(nodeType, childNode);
+        return new Node(nodeType, childNode);
     }
 
     public Object createUnary(int nodeType, int nodeOp, Object child) {
@@ -810,7 +811,7 @@ public class IRFactory {
             return createTernary(temp, createUseTemp(temp), right);
 */            
         }
-    	return new Node(nodeType, (Node)left, (Node)right);
+        return new Node(nodeType, (Node)left, (Node)right);
     }
 
     public Object createBinary(int nodeType, int nodeOp, Object left,

js/rhino/src/org/mozilla/javascript/Node.java

@@ -147,10 +147,6 @@ public class Node implements Cloneable {
         return n;
     }
 
-    public ShallowNodeIterator getChildIterator() {
-        return new ShallowNodeIterator(first);
-    }
-
     public PreorderNodeIterator getPreorderIterator() {
         return new PreorderNodeIterator(this);
     }
@@ -484,17 +480,16 @@ public class Node implements Cloneable {
             }
             s.append(toString());
             s.append('\n');
-            ShallowNodeIterator iterator = getChildIterator();
-            if (iterator != null) {
-                while (iterator.hasMoreElements()) {
-                    Node n = (Node) iterator.nextElement();
-                    if (n.getType() == TokenStream.FUNCTION) {
-                        Node p = (Node) n.getProp(Node.FUNCTION_PROP);
-                        if (p != null)
-                            n = p;
-                    }
-                    s.append(n.toStringTreeHelper(level+1));
+            for (Node cursor = getFirstChild(); cursor != null;
+                 cursor = cursor.getNextSibling()) 
+            {
+                Node n = cursor;
+                if (cursor.getType() == TokenStream.FUNCTION) {
+                    Node p = (Node) cursor.getProp(Node.FUNCTION_PROP);
+                    if (p != null)
+                        n = p;
                 }
+                s.append(n.toStringTreeHelper(level+1));
             }
             return s.toString();
         }

js/rhino/src/org/mozilla/javascript/NodeTransformer.java

@@ -407,10 +407,12 @@ public class NodeTransformer {
 
               case TokenStream.VAR:
               {
-                ShallowNodeIterator i = node.getChildIterator();
                 Node result = new Node(TokenStream.BLOCK);
-                while (i.hasMoreElements()) {
-                    Node n = i.nextNode();
+                for (Node cursor = node.getFirstChild(); cursor != null;) {
+                    // Move cursor to next before createAssignment get chance
+                    // to change n.next
+                    Node n = cursor;
+                    cursor = cursor.getNextSibling();
                     if (!n.hasChildren())
                         continue;
                     Node init = n.getFirstChild();
@@ -519,11 +521,11 @@ public class NodeTransformer {
             }
             if (nodeType != TokenStream.VAR)
                 continue;
-            ShallowNodeIterator i = node.getChildIterator();
-            while (i.hasMoreElements()) {
-                Node n = i.nextNode();
-                if (ht == null || ht.get(n.getString()) == null)
-                    vars.addLocal(n.getString());
+            for (Node cursor = node.getFirstChild(); cursor != null;
+                 cursor = cursor.getNextSibling()) 
+            {
+                if (ht == null || ht.get(cursor.getString()) == null)
+                    vars.addLocal(cursor.getString());
             }
         }
         String name = tree.getString();
@@ -554,10 +556,10 @@ public class NodeTransformer {
         if (args.getType() == TokenStream.LP && vars.getParameterCount() == 0)
         {
             // Add parameters
-            ShallowNodeIterator i = args.getChildIterator();
-            while (i.hasMoreElements()) {
-                Node n = i.nextNode();
-                String arg = n.getString();
+            for (Node cursor = args.getFirstChild(); cursor != null;
+                 cursor = cursor.getNextSibling()) 
+            {
+                String arg = cursor.getString();
                 vars.addParameter(arg);
             }
         }