From 8fd2b9225a6f9b5143507518d9a235818abef1ae Mon Sep 17 00:00:00 2001
From: Dion <qdraw@users.noreply.github.com>
Date: Wed, 24 Apr 2024 15:54:44 +0200
Subject: [PATCH] #1537 add regex timeout

---
 .../Helpers/ExtensionRolesHelper.cs           | 34 ++++++++++---------
 1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/starsky/starsky.foundation.platform/Helpers/ExtensionRolesHelper.cs b/starsky/starsky.foundation.platform/Helpers/ExtensionRolesHelper.cs
index e65a253f58..8df8f18f3a 100644
--- a/starsky/starsky.foundation.platform/Helpers/ExtensionRolesHelper.cs
+++ b/starsky/starsky.foundation.platform/Helpers/ExtensionRolesHelper.cs
@@ -8,7 +8,7 @@
 
 namespace starsky.foundation.platform.Helpers
 {
-	public static class ExtensionRolesHelper
+	public static partial class ExtensionRolesHelper
 	{
 		/// <summary>
 		/// Xmp sidecar file
@@ -88,12 +88,8 @@ private static readonly Dictionary<ImageFormat, List<string>>
 		public static ImageFormat MapFileTypesToExtension(string filename)
 		{
 			if ( string.IsNullOrEmpty(filename) ) return ImageFormat.unknown;
-
-			// without escaped values:
-			//		\.([0-9a-z]+)(?=[?#])|(\.)(?:[\w]+)$
-			var matchCollection = new Regex("\\.([0-9a-z]+)(?=[?#])|(\\.)(?:[\\w]+)$",
-				RegexOptions.None, TimeSpan.FromMilliseconds(100)
-			).Matches(filename);
+			
+			var matchCollection = FileExtensionRegex().Matches(filename);
 			if ( matchCollection.Count == 0 )
 			{
 				return ImageFormat.unknown;
@@ -280,11 +276,8 @@ public static bool IsExtensionSidecar(string? filename)
 		private static bool IsExtensionForce(string? filename, List<string> checkThisList)
 		{
 			if ( string.IsNullOrEmpty(filename) ) return false;
-
-			// without escaped values:
-			//		\.([0-9a-z]+)(?=[?#])|(\.)(?:[\w]+)$
-			var matchCollection = new Regex("\\.([0-9a-z]+)(?=[?#])|(\\.)(?:[\\w]+)$",
-				RegexOptions.IgnoreCase, TimeSpan.FromMilliseconds(200)).Matches(filename);
+			
+			var matchCollection = FileExtensionRegex().Matches(filename);
 
 			if ( matchCollection.Count == 0 ) return false;
 			foreach ( var matchValue in matchCollection.Select(p => p.Value) )
@@ -316,10 +309,7 @@ public static string ReplaceExtensionWithXmp(string? filename)
 				return string.Empty;
 			}
 
-			// without escaped values:
-			//		\.([0-9a-z]+)(?=[?#])|(\.)(?:[\w]+)$
-			var matchCollection = new Regex("\\.([0-9a-z]+)(?=[?#])|(\\.)(?:[\\w]+)$",
-				RegexOptions.None, TimeSpan.FromMilliseconds(100)).Matches(filename);
+			var matchCollection = FileExtensionRegex().Matches(filename);
 
 			if ( matchCollection.Count == 0 ) return string.Empty;
 			foreach ( Match match in matchCollection )
@@ -339,6 +329,18 @@ public static string ReplaceExtensionWithXmp(string? filename)
 
 			return string.Empty;
 		}
+		
+		/// <summary>
+		/// Check for file extensions
+		/// without escaped values:
+		///		\.([0-9a-z]+)(?=[?#])|(\.)(?:[\w]+)$
+		/// </summary>
+		/// <returns>Regex object</returns>
+		[GeneratedRegex(
+			@"\.([0-9a-z]+)(?=[?#])|(\.)(?:[\w]+)$",
+			RegexOptions.CultureInvariant | RegexOptions.IgnoreCase,
+			matchTimeoutMilliseconds: 500)]
+		private static partial Regex FileExtensionRegex();
 
 		/// <summary>
 		/// ImageFormat based on first bytes