From a15998b6e2dc749a5f8c0bd0c711d548738d6468 Mon Sep 17 00:00:00 2001
From: Alexander Ebert <ebert@woltlab.com>
Date: Mon, 12 Apr 2021 22:01:30 +0200
Subject: [PATCH] Use `XPath::query()` for its superior performance

---
 .../node/HtmlOutputNodeProcessor.class.php    | 24 +++++--------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/wcfsetup/install/files/lib/system/html/output/node/HtmlOutputNodeProcessor.class.php b/wcfsetup/install/files/lib/system/html/output/node/HtmlOutputNodeProcessor.class.php
index 866ba51c1f..d2e54f1740 100644
--- a/wcfsetup/install/files/lib/system/html/output/node/HtmlOutputNodeProcessor.class.php
+++ b/wcfsetup/install/files/lib/system/html/output/node/HtmlOutputNodeProcessor.class.php
@@ -91,22 +91,15 @@ class HtmlOutputNodeProcessor extends AbstractHtmlNodeProcessor {
 		$this->invokeNodeHandlers('wcf\system\html\output\node\HtmlOutputNode', ['woltlab-metacode']);
 		
 		if ($this->getHtmlProcessor()->removeLinks) {
-			$links = $this->getDocument()->getElementsByTagName('a');
-			while ($links->length) {
-				DOMUtil::removeNode($links->item(0), true);
+			foreach ($this->getXPath()->query('//a') as $link) {
+				DOMUtil::removeNode($link, true);
 			}
 		}
 		
 		if ($this->outputType !== 'text/html') {
 			// convert `<p>...</p>` into `...<br><br>`
 			$paragraphs = [];
-			// The DOMNodeList returned by `getElementsByTagName()` is live, causing a performance
-			// penalty when modifying it a lot.
-			foreach ($this->getDocument()->getElementsByTagName('p') as $node) {
-				$paragraphs[] = $node;
-			}
-			
-			foreach ($paragraphs as $paragraph) {
+			foreach ($this->getXPath()->query('//p') as $paragraph) {
 				$isLastNode = true;
 				$sibling = $paragraph;
 				while ($sibling = $sibling->nextSibling) {
@@ -147,7 +140,6 @@ class HtmlOutputNodeProcessor extends AbstractHtmlNodeProcessor {
 				
 				DOMUtil::removeNode($paragraph, true);
 			}
-			unset($paragraphs);
 			
 			if ($this->outputType === 'text/plain') {
 				// remove all `\n` first
@@ -166,10 +158,7 @@ class HtmlOutputNodeProcessor extends AbstractHtmlNodeProcessor {
 				
 				// insert a trailing newline for certain elements, such as `<br>` or `<li>`
 				foreach (self::$plainTextNewlineTags as $tagName) {
-					$elements = $this->getDocument()->getElementsByTagName($tagName);
-					while ($elements->length) {
-						$element = $elements->item(0);
-						
+					foreach ($this->getXPath()->query("//{$tagName}") as $element) {
 						$newline = $this->getDocument()->createTextNode("\n");
 						$element->parentNode->insertBefore($newline, $element->nextSibling);
 						DOMUtil::removeNode($element, true);
@@ -177,9 +166,8 @@ class HtmlOutputNodeProcessor extends AbstractHtmlNodeProcessor {
 				}
 				
 				// remove all other elements
-				$elements = $this->getDocument()->getElementsByTagName('*');
-				while ($elements->length) {
-					DOMUtil::removeNode($elements->item(0), true);
+				foreach ($this->getXPath()->query('//*') as $element) {
+					DOMUtil::removeNode($element, true);
 				}
 			}
 		}
-- 
2.20.1