From 4a166a45ec9db910542893133f08cc7de4ec974f Mon Sep 17 00:00:00 2001
From: Timothy Flynn <trflynn89@pm.me>
Date: Tue, 30 Jul 2024 06:46:30 -0400
Subject: [PATCH] LibWeb: Avoid allocating UTF-16 strings only the UTF-16
 length is needed

---
 Userland/Libraries/LibWeb/DOM/CharacterData.h          | 5 ++---
 Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.cpp | 5 ++---
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/Userland/Libraries/LibWeb/DOM/CharacterData.h b/Userland/Libraries/LibWeb/DOM/CharacterData.h
index 431b45b655d..0598c8d88db 100644
--- a/Userland/Libraries/LibWeb/DOM/CharacterData.h
+++ b/Userland/Libraries/LibWeb/DOM/CharacterData.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include <AK/String.h>
+#include <AK/Utf16View.h>
 #include <LibUnicode/Forward.h>
 #include <LibWeb/DOM/ChildNode.h>
 #include <LibWeb/DOM/Node.h>
@@ -30,9 +31,7 @@ public:
 
     unsigned length_in_utf16_code_units() const
     {
-        // FIXME: This is inefficient!
-        auto utf16_data = MUST(AK::utf8_to_utf16(m_data));
-        return Utf16View { utf16_data }.length_in_code_units();
+        return AK::utf16_code_unit_length_from_utf8(m_data);
     }
 
     WebIDL::ExceptionOr<String> substring_data(size_t offset_in_utf16_code_units, size_t count_in_utf16_code_units) const;
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.cpp
index bcbb56e4adc..71f100e2108 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLTextAreaElement.cpp
@@ -6,6 +6,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/Utf16View.h>
 #include <LibWeb/Bindings/HTMLTextAreaElementPrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/CSS/StyleProperties.h>
@@ -189,9 +190,7 @@ String HTMLTextAreaElement::api_value() const
 u32 HTMLTextAreaElement::text_length() const
 {
     // The textLength IDL attribute must return the length of the element's API value.
-    // FIXME: This is inefficient!
-    auto utf16_data = MUST(AK::utf8_to_utf16(api_value()));
-    return Utf16View { utf16_data }.length_in_code_units();
+    return AK::utf16_code_unit_length_from_utf8(api_value());
 }
 
 // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#dom-cva-checkvalidity