From cbd5ef9ca8a577613d32f5971ee7b94f43676ce6 Mon Sep 17 00:00:00 2001
From: William Forney <william@williamforney.com>
Date: Wed, 16 Sep 2026 09:09:26 -0700
Subject: [PATCH] Cache GUID validation regex

Avoid compiling the GUID validation regex on every call and use the source-generated regex on modern target frameworks.\n\nCo-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
---
 SharedCode.Core/Text/StringExtensions.cs | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/SharedCode.Core/Text/StringExtensions.cs b/SharedCode.Core/Text/StringExtensions.cs
index cb7c044..9a58cdf 100644
--- a/SharedCode.Core/Text/StringExtensions.cs
+++ b/SharedCode.Core/Text/StringExtensions.cs
@@ -12,6 +12,12 @@ namespace SharedCode.Text;
 /// </summary>
 public static partial class StringExtensions
 {
+	private const string GuidPattern =
+		"^[A-Fa-f0-9]{32}$|"
+		+ "^({|\\()?[A-Fa-f0-9]{8}-([A-Fa-f0-9]{4}-){3}[A-Fa-f0-9]{12}(}|\\))?$|"
+		+ "^({)?[0xA-Fa-f0-9]{3,10}(, {0,1}[0xA-Fa-f0-9]{3,6}){2}, {0,1}({)"
+		+ "([0xA-Fa-f0-9]{3,4}, {0,1}){7}[0xA-Fa-f0-9]{3,4}(}})$";
+
 	/// <summary>
 	/// Default masking character used in a mask.
 	/// </summary>
@@ -419,12 +425,11 @@ public static bool IsGuid(this string @this)
 	{
 		_ = @this ?? throw new ArgumentNullException(nameof(@this));
 
-		var format = new Regex(
-			"^[A-Fa-f0-9]{32}$|" + "^({|\\()?[A-Fa-f0-9]{8}-([A-Fa-f0-9]{4}-){3}[A-Fa-f0-9]{12}(}|\\))?$|"
-			+ "^({)?[0xA-Fa-f0-9]{3,10}(, {0,1}[0xA-Fa-f0-9]{3,6}){2}, {0,1}({)([0xA-Fa-f0-9]{3,4}, {0,1}){7}[0xA-Fa-f0-9]{3,4}(}})$");
-		var match = format.Match(@this);
-
-		return match.Success;
+#if NET8_0_OR_GREATER
+		return GuidRegex().IsMatch(@this);
+#else
+		return GuidRegex.IsMatch(@this);
+#endif
 	}
 
 	/// <summary>
@@ -950,5 +955,10 @@ private static void CreateAlphaNumMask(StringBuilder buffer, string source, char
 #if NET8_0_OR_GREATER
 	[GeneratedRegex("</?.+?>")]
 	private static partial Regex HtmlTagRegex();
+
+	[GeneratedRegex(GuidPattern)]
+	private static partial Regex GuidRegex();
+#else
+	private static readonly Regex GuidRegex = new(GuidPattern, RegexOptions.Compiled);
 #endif
 }