From 1466a7364c1b0b3ff3c7fdd2af3a45a068d72c6e Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Tue, 5 Nov 2019 18:36:06 +0100
Subject: [PATCH] LibHTML: Add TreeNode::next_in_pre_order()

This function allows you to traverse in pre-order without recursing.
---
 Libraries/LibHTML/TreeNode.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Libraries/LibHTML/TreeNode.h b/Libraries/LibHTML/TreeNode.h
index d368b6c347..8461fd3160 100644
--- a/Libraries/LibHTML/TreeNode.h
+++ b/Libraries/LibHTML/TreeNode.h
@@ -53,6 +53,26 @@ public:
 
     bool is_child_allowed(const T&) const { return true; }
 
+    T* next_in_pre_order()
+    {
+        if (first_child())
+            return first_child();
+        T* node;
+        if (!(node = next_sibling())) {
+            node = parent();
+            while (node && !node->next_sibling())
+                node = node->parent();
+            if (node)
+                node = node->next_sibling();
+        }
+        return node;
+    }
+
+    const T* next_in_pre_order() const
+    {
+        return const_cast<TreeNode*>(this)->next_in_pre_order();
+    }
+
     template<typename Callback>
     IterationDecision for_each_in_subtree(Callback callback) const
     {