From 2825ec6693e2c47741cebaefd2cdb1ecfac31746 Mon Sep 17 00:00:00 2001
From: Shannon Deminick <sdeminick@gmail.com>
Date: Mon, 7 Jun 2021 21:10:50 +1000
Subject: [PATCH] Removes CallContext (#10398)

---
 src/Umbraco.Core/HybridAccessorBase.cs  |  8 +++--
 src/Umbraco.Core/Scoping/CallContext.cs | 48 -------------------------
 2 files changed, 5 insertions(+), 51 deletions(-)
 delete mode 100644 src/Umbraco.Core/Scoping/CallContext.cs

diff --git a/src/Umbraco.Core/HybridAccessorBase.cs b/src/Umbraco.Core/HybridAccessorBase.cs
index 530d1d5689..1bb7635dcc 100644
--- a/src/Umbraco.Core/HybridAccessorBase.cs
+++ b/src/Umbraco.Core/HybridAccessorBase.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Threading;
 using Umbraco.Cms.Core.Cache;
 using Umbraco.Cms.Core.Scoping;
 
@@ -16,9 +17,10 @@ namespace Umbraco.Cms.Core
     public abstract class HybridAccessorBase<T>
         where T : class
     {
+        private static readonly AsyncLocal<T> s_ambientContext = new AsyncLocal<T>();
+
         private readonly IRequestCache _requestCache;
         private string _itemKey;
-
         protected string ItemKey => _itemKey ??= GetType().FullName;
 
         // read
@@ -38,8 +40,8 @@ namespace Umbraco.Cms.Core
         // yes! flows with async!
         private T NonContextValue
         {
-            get => CallContext<T>.GetData(ItemKey);
-            set => CallContext<T>.SetData(ItemKey, value);
+            get => s_ambientContext.Value ?? default;
+            set => s_ambientContext.Value = value;
         }
 
         protected HybridAccessorBase(IRequestCache requestCache)
diff --git a/src/Umbraco.Core/Scoping/CallContext.cs b/src/Umbraco.Core/Scoping/CallContext.cs
deleted file mode 100644
index b77414ddd6..0000000000
--- a/src/Umbraco.Core/Scoping/CallContext.cs
+++ /dev/null
@@ -1,48 +0,0 @@
-using System.Collections.Concurrent;
-using System.Threading;
-
-namespace Umbraco.Cms.Core.Scoping
-{
-    /// <summary>
-    /// Represents ambient data that is local to a given asynchronous control flow, such as an asynchronous method.
-    /// </summary>
-    /// <remarks>
-    /// This is just a simple wrapper around <seealso cref="AsyncLocal{T}"/>
-    /// </remarks>
-    public static class CallContext<T>
-    {
-        // TODO: Kill this. Wherever we need AsyncLocal, we should just use it there.
-
-        private static readonly ConcurrentDictionary<string, AsyncLocal<T>> s_state = new ConcurrentDictionary<string, AsyncLocal<T>>();
-
-        /// <summary>
-        /// Stores a given object and associates it with the specified name.
-        /// </summary>
-        /// <param name="name">The name with which to associate the new item in the call context.</param>
-        /// <param name="data">The object to store in the call context.</param>
-        public static void SetData(string name, T data) => s_state.GetOrAdd(name, _ => new AsyncLocal<T>()).Value = data;
-
-        //Replace the SetData with the following when you need to debug AsyncLocal. The args.ThreadContextChanged can be usefull
-        //public static void SetData(string name, T data) => _state.GetOrAdd(name, _ => new AsyncLocal<T>(OnValueChanged)).Value = data;
-        // public static void OnValueChanged(AsyncLocalValueChangedArgs<T> args)
-        // {
-        //     var typeName = typeof(T).ToString();
-        //     Console.WriteLine($"OnValueChanged!, Type: {typeName} Prev: #{args.PreviousValue} Current: #{args.CurrentValue}");
-        // }
-
-        /// <summary>
-        /// Retrieves an object with the specified name from the <see cref="CallContext{T}"/>.
-        /// </summary>
-        /// <typeparam name="T">The type of the data being retrieved. Must match the type used when the <paramref name="name"/> was set via <see cref="SetData{T}(string, T)"/>.</typeparam>
-        /// <param name="name">The name of the item in the call context.</param>
-        /// <returns>The object in the call context associated with the specified name, or a default value for <typeparamref name="T"/> if none is found.</returns>
-        public static T GetData(string name) => s_state.TryGetValue(name, out AsyncLocal<T> data) ? data.Value : default;
-
-        // NOTE: If you have used the old CallContext in the past you might be thinking you need to clean this up but that is not the case.
-        // With CallContext you had to call FreeNamedDataSlot to prevent leaks but with AsyncLocal this is not the case, there is no way to clean this up.
-        // The above dictionary is sort of a trick because sure, there is always going to be a string key that will exist in the collection but the values
-        // themselves are managed per ExecutionContext so they don't build up.
-        // There's an SO article relating to this here https://stackoverflow.com/questions/36511243/safety-of-asynclocal-in-asp-net-core
-
-    }
-}