From 0f1b03df354f8f726e35e2eb482536c9c2af9aa4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Velad=20Galv=C3=A1n?= <ladvan91@hotmail.com>
Date: Fri, 13 Sep 2024 13:49:39 +0200
Subject: [PATCH] perf: Only use tXml parent when necessary (#7304)

Issue https://github.com/shaka-project/shaka-player/issues/6239
---
 lib/dash/mpd_utils.js        |  3 ---
 lib/text/ttml_text_parser.js |  2 +-
 lib/util/tXml.js             | 26 +++++++++++++++++---------
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/lib/dash/mpd_utils.js b/lib/dash/mpd_utils.js
index a0755aa353..360d11178d 100644
--- a/lib/dash/mpd_utils.js
+++ b/lib/dash/mpd_utils.js
@@ -481,9 +481,6 @@ shaka.dash.MpdUtils = class {
           // Move the children of the loaded xml into the current element.
           while (rootElem.children.length) {
             const child = rootElem.children.shift();
-            if (TXml.isNode(child)) {
-              child.parent = element;
-            }
             element.children.push(child);
           }
 
diff --git a/lib/text/ttml_text_parser.js b/lib/text/ttml_text_parser.js
index ca1c5544b4..8682c6ee19 100644
--- a/lib/text/ttml_text_parser.js
+++ b/lib/text/ttml_text_parser.js
@@ -65,7 +65,7 @@ shaka.text.TtmlTextParser = class {
       return cues;
     }
 
-    const tt = TXml.parseXmlString(str, 'tt');
+    const tt = TXml.parseXmlString(str, 'tt', /* includeParent= */ true);
     if (!tt) {
       throw new shaka.util.Error(
           shaka.util.Error.Severity.CRITICAL,
diff --git a/lib/util/tXml.js b/lib/util/tXml.js
index bb60f395a5..395517ebb8 100644
--- a/lib/util/tXml.js
+++ b/lib/util/tXml.js
@@ -44,11 +44,13 @@ shaka.util.TXml = class {
    * Parse some data
    * @param {BufferSource} data
    * @param {string=} expectedRootElemName
+   * @param {boolean=} includeParent
    * @return {shaka.extern.xml.Node | null}
    */
-  static parseXml(data, expectedRootElemName) {
+  static parseXml(data, expectedRootElemName, includeParent = false) {
     const xmlString = shaka.util.StringUtils.fromBytesAutoDetect(data);
-    return shaka.util.TXml.parseXmlString(xmlString, expectedRootElemName);
+    return shaka.util.TXml.parseXmlString(
+        xmlString, expectedRootElemName, includeParent);
   }
 
   /**
@@ -57,8 +59,9 @@ shaka.util.TXml = class {
    * @param {string=} expectedRootElemName
    * @return {shaka.extern.xml.Node | null}
    */
-  static parseXmlString(xmlString, expectedRootElemName) {
-    const result = shaka.util.TXml.parse(xmlString);
+  static parseXmlString(xmlString, expectedRootElemName,
+      includeParent = false) {
+    const result = shaka.util.TXml.parse(xmlString, includeParent);
     if (!expectedRootElemName && result.length) {
       return result[0];
     }
@@ -109,9 +112,10 @@ shaka.util.TXml = class {
    * parseXML / html into a DOM Object,
    * with no validation and some failure tolerance
    * @param {string} S your XML to parse
+   * @param {boolean} includeParent
    * @return {Array.<shaka.extern.xml.Node>}
    */
-  static parse(S) {
+  static parse(S, includeParent) {
     let pos = 0;
 
     const openBracket = '<';
@@ -286,9 +290,11 @@ shaka.util.TXml = class {
                 children,
                 parent: null,
               };
-              for (let i = 0; i < children.length; i++) {
-                if (typeof children[i] !== 'string') {
-                  children[i].parent = node;
+              if (includeParent) {
+                for (let i = 0; i < children.length; i++) {
+                  if (typeof children[i] !== 'string') {
+                    children[i].parent = node;
+                  }
                 }
               }
               return node;
@@ -330,7 +336,9 @@ shaka.util.TXml = class {
       for (let i = 0; i < childrenLength; i++) {
         const childrenValue = children[i];
         if (typeof childrenValue !== 'string') {
-          childrenValue.parent = node;
+          if (includeParent) {
+            childrenValue.parent = node;
+          }
         } else if (i == childrenLength - 1 && childrenValue == '\n') {
           children.pop();
         }