From 83c927859303219ab5ac47f4aaa9d360dba8444d Mon Sep 17 00:00:00 2001
From: Mahdi Golestan <Mahdi Golestan>
Date: Sat, 31 Aug 2024 18:41:54 +0330
Subject: [PATCH] Use ConcurrentDictionary For Improving GetEnumFromDisplayName

---
 .../Extensions/StringExtensions.cs            | 22 +++++++++++++------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/Microsoft.OpenApi/Extensions/StringExtensions.cs b/src/Microsoft.OpenApi/Extensions/StringExtensions.cs
index 541523df5..00c26575e 100644
--- a/src/Microsoft.OpenApi/Extensions/StringExtensions.cs
+++ b/src/Microsoft.OpenApi/Extensions/StringExtensions.cs
@@ -1,7 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
-
 using System;
+using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using Microsoft.OpenApi.Attributes;
@@ -13,6 +13,8 @@ namespace Microsoft.OpenApi.Extensions
     /// </summary>
     public static class StringExtensions
     {
+        private static readonly ConcurrentDictionary<Type, ConcurrentDictionary<string, object>> EnumDisplayCache = new();
+
         /// <summary>
         /// Gets the enum value based on the given enum type and display name.
         /// </summary>
@@ -21,22 +23,28 @@ public static class StringExtensions
         {
             var type = typeof(T);
             if (!type.IsEnum)
-            {
                 return default;
-            }
+
+            var displayMap = EnumDisplayCache.GetOrAdd(type, _ => new ConcurrentDictionary<string, object>(StringComparer.OrdinalIgnoreCase));
+
+            if (displayMap.TryGetValue(displayName, out var cachedValue))
+                return (T)cachedValue;
+
 
             foreach (var field in type.GetFields(BindingFlags.Public | BindingFlags.Static))
             {
-                var displayAttribute = (DisplayAttribute)field.GetCustomAttribute(typeof(DisplayAttribute));
-                if (displayAttribute != null && displayAttribute.Name == displayName)
+                var displayAttribute = field.GetCustomAttribute<DisplayAttribute>();
+                if (displayAttribute != null && displayAttribute.Name.Equals(displayName, StringComparison.OrdinalIgnoreCase))
                 {
-                    return (T)field.GetValue(null);
+                    var enumValue = (T)field.GetValue(null);
+                    displayMap.TryAdd(displayName, enumValue);
+                    return enumValue;
                 }
             }
 
             return default;
         }
         internal static string ToFirstCharacterLowerCase(this string input)
-        => string.IsNullOrEmpty(input) ? string.Empty : char.ToLowerInvariant(input[0]) + input.Substring(1);
+            => string.IsNullOrEmpty(input) ? string.Empty : char.ToLowerInvariant(input[0]) + input.Substring(1);
     }
 }