From e1fb9de9770e5f56d463d1d5f41b9d54e4375e04 Mon Sep 17 00:00:00 2001
From: Dean Marcussen <dean.marcussen@gmail.com>
Date: Thu, 13 Jan 2022 10:10:48 +0000
Subject: [PATCH] Tidy up unused ConcurrentDictionary Extensions

---
 .../ConcurrentDictionaryExtensions.cs         | 63 -------------------
 1 file changed, 63 deletions(-)
 delete mode 100644 src/ImageSharp.Web/Middleware/ConcurrentDictionaryExtensions.cs

diff --git a/src/ImageSharp.Web/Middleware/ConcurrentDictionaryExtensions.cs b/src/ImageSharp.Web/Middleware/ConcurrentDictionaryExtensions.cs
deleted file mode 100644
index 09b77544..00000000
--- a/src/ImageSharp.Web/Middleware/ConcurrentDictionaryExtensions.cs
+++ /dev/null
@@ -1,63 +0,0 @@
-// Copyright (c) Six Labors.
-// Licensed under the Apache License, Version 2.0.
-
-using System;
-using System.Collections.Concurrent;
-using System.Threading.Tasks;
-
-namespace SixLabors.ImageSharp.Web.Middleware
-{
-    /// <summary>
-    /// Extensions used to manage asynchronous access to the <see cref="ImageSharpMiddleware"/>
-    /// https://gist.github.com/davidfowl/3dac8f7b3d141ae87abf770d5781feed
-    /// </summary>
-    public static class ConcurrentDictionaryExtensions
-    {
-        /// <summary>
-        /// Provides an alternative to <see cref="ConcurrentDictionary{TKey, TValue}.GetOrAdd(TKey, Func{TKey, TValue})"/> specifically for asynchronous values. The factory method will only run once.
-        /// </summary>
-        /// <typeparam name="TKey">The type of the key.</typeparam>
-        /// <typeparam name="TValue">The value for the dictionary.</typeparam>
-        /// <param name="dictionary">The <see cref="ConcurrentDictionary{TKey, TValue}"/>.</param>
-        /// <param name="key">The key of the element to add.</param>
-        /// <param name="valueFactory">The function used to generate a value for the key</param>
-        /// <returns>The value for the key.  This will be either the existing value for the key if the
-        /// key is already in the dictionary, or the new value for the key as returned by valueFactory
-        /// if the key was not in the dictionary.</returns>
-        public static async Task<TValue> GetOrAddAsync<TKey, TValue>(
-            this ConcurrentDictionary<TKey, Task<TValue>> dictionary,
-            TKey key,
-            Func<TKey, Task<TValue>> valueFactory)
-        {
-            while (true)
-            {
-                if (dictionary.TryGetValue(key, out var task))
-                {
-                    return await task;
-                }
-
-                // This is the task that we'll return to all waiters. We'll complete it when the factory is complete
-                var tcs = new TaskCompletionSource<TValue>(TaskCreationOptions.RunContinuationsAsynchronously);
-                if (dictionary.TryAdd(key, tcs.Task))
-                {
-                    try
-                    {
-                        var value = await valueFactory(key);
-                        tcs.TrySetResult(value);
-                        return await tcs.Task;
-                    }
-                    catch (Exception ex)
-                    {
-                        // Make sure all waiters see the exception
-                        tcs.SetException(ex);
-
-                        // We remove the entry if the factory failed so it's not a permanent failure
-                        // and future gets can retry (this could be a pluggable policy)
-                        dictionary.TryRemove(key, out _);
-                        throw;
-                    }
-                }
-            }
-        }
-    }
-}