From 0bdf88f5074d963dbd03fca5174b2f81241f387a Mon Sep 17 00:00:00 2001
From: Niels Dossche <7771979+nielsdos@users.noreply.github.com>
Date: Wed, 2 Oct 2024 23:00:18 +0200
Subject: [PATCH] Don't use recursion when transferring a DOM internal document
 pointer

Recursion is typically slower than iteration, and furthermore, this can
cause problems in theory with deep trees.
---
 ext/dom/document.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/ext/dom/document.c b/ext/dom/document.c
index 9650d0902909a..804efe727ffca 100644
--- a/ext/dom/document.c
+++ b/ext/dom/document.c
@@ -1074,7 +1074,7 @@ PHP_METHOD(DOMDocument, getElementById)
 }
 /* }}} end dom_document_get_element_by_id */
 
-static zend_always_inline void php_dom_transfer_document_ref_single_node(xmlNodePtr node, php_libxml_ref_obj *new_document)
+static void php_dom_transfer_document_ref_single_node(xmlNodePtr node, php_libxml_ref_obj *new_document)
 {
 	php_libxml_node_ptr *iteration_object_ptr = node->_private;
 	if (iteration_object_ptr) {
@@ -1087,21 +1087,25 @@ static zend_always_inline void php_dom_transfer_document_ref_single_node(xmlNode
 	}
 }
 
-static void php_dom_transfer_document_ref(xmlNodePtr node, php_libxml_ref_obj *new_document)
+static void php_dom_transfer_document_ref_single_aux(xmlNodePtr node, php_libxml_ref_obj *new_document)
 {
-	if (node->children) {
-		php_dom_transfer_document_ref(node->children, new_document);
+	php_dom_transfer_document_ref_single_node(node, new_document);
+	if (node->type == XML_ELEMENT_NODE) {
+		for (xmlAttrPtr attr = node->properties; attr != NULL; attr = attr->next) {
+			php_dom_transfer_document_ref_single_node((xmlNodePtr) attr, new_document);
+		}
 	}
+}
 
-	while (node) {
-		if (node->type == XML_ELEMENT_NODE) {
-			for (xmlAttrPtr attr = node->properties; attr != NULL; attr = attr->next) {
-				php_dom_transfer_document_ref_single_node((xmlNodePtr) attr, new_document);
-			}
-		}
+static void php_dom_transfer_document_ref(xmlNodePtr node, php_libxml_ref_obj *new_document)
+{
+	xmlNodePtr base = node;
+	php_dom_transfer_document_ref_single_aux(base, new_document);
 
-		php_dom_transfer_document_ref_single_node(node, new_document);
-		node = node->next;
+	node = node->children;
+	while (node != NULL) {
+		php_dom_transfer_document_ref_single_aux(node, new_document);
+		node = php_dom_next_in_tree_order(node, base);
 	}
 }