Add support for updateable ActionDescriptorCollection

Fixes #5350

src/Microsoft.AspNetCore.Mvc.Core/Infrastructure/IActionDescriptorChangeProvider.cs

@@ -0,0 +1,21 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.Extensions.Primitives;
+
+namespace Microsoft.AspNetCore.Mvc.Infrastructure
+{
+    /// <summary>
+    /// Provides a way to signal invalidation of the cached collection of <see cref="Abstractions.ActionDescriptor" /> from an
+    /// <see cref="IActionDescriptorCollectionProvider"/>.
+    /// </summary>
+    public interface IActionDescriptorChangeProvider
+    {
+        /// <summary>
+        /// Gets a <see cref="IChangeToken"/> used to signal invalidation of cached <see cref="Abstractions.ActionDescriptor"/>
+        /// instances.
+        /// </summary>
+        /// <returns>The <see cref="IChangeToken"/>.</returns>
+        IChangeToken GetChangeToken();
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/Infrastructure/IActionDescriptorCollectionProvider.cs

@@ -7,10 +7,9 @@ namespace Microsoft.AspNetCore.Mvc.Infrastructure
     /// Provides the currently cached collection of <see cref="Abstractions.ActionDescriptor"/>.
     /// </summary>
     /// <remarks>
-    /// The default implementation, does not update the cache, it is up to the user
-    /// to create or use an implementation that can update the available actions in
-    /// the application. The implementor is also responsible for updating the
-    /// <see cref="ActionDescriptorCollection.Version"/> in a thread safe way.
+    /// The default implementation internally caches the collection and uses
+    /// <see cref="IActionDescriptorChangeProvider"/> to invalidate this cache, incrementing
+    /// <see cref="ActionDescriptorCollection.Version"/> the collection is reconstructed.
     ///
     /// Default consumers of this service, are aware of the version and will recache
     /// data as appropriate, but rely on the version being unique.

src/Microsoft.AspNetCore.Mvc.Core/Internal/ActionDescriptorCollectionProvider.cs

@@ -1,31 +1,55 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
+using System.Threading;
 using Microsoft.AspNetCore.Mvc.Abstractions;
 using Microsoft.AspNetCore.Mvc.Infrastructure;
-using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Primitives;
 
 namespace Microsoft.AspNetCore.Mvc.Internal
 {
     /// <summary>
     /// Default implementation of <see cref="IActionDescriptorCollectionProvider"/>.
-    /// This implementation caches the results at first call, and is not responsible for updates.
     /// </summary>
     public class ActionDescriptorCollectionProvider : IActionDescriptorCollectionProvider
     {
-        private readonly IServiceProvider _serviceProvider;
+        private readonly IActionDescriptorProvider[] _actionDescriptorProviders;
+        private readonly IActionDescriptorChangeProvider[] _actionDescriptorChangeProviders;
         private ActionDescriptorCollection _collection;
+        private int _version = -1;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="ActionDescriptorCollectionProvider" /> class.
         /// </summary>
-        /// <param name="serviceProvider">The application IServiceProvider.</param>
-        public ActionDescriptorCollectionProvider(IServiceProvider serviceProvider)
+        /// <param name="actionDescriptorProviders">The sequence of <see cref="IActionDescriptorProvider"/>.</param>
+        /// <param name="actionDescriptorChangeProviders">The sequence of <see cref="IActionDescriptorChangeProvider"/>.</param>
+        public ActionDescriptorCollectionProvider(
+            IEnumerable<IActionDescriptorProvider> actionDescriptorProviders,
+            IEnumerable<IActionDescriptorChangeProvider> actionDescriptorChangeProviders)
         {
-            _serviceProvider = serviceProvider;
+            _actionDescriptorProviders = actionDescriptorProviders
+                .OrderBy(p => p.Order)
+                .ToArray();
+
+            _actionDescriptorChangeProviders = actionDescriptorChangeProviders.ToArray();
+
+            ChangeToken.OnChange(
+                GetCompositeChangeToken,
+                UpdateCollection);
+        }
+
+        private IChangeToken GetCompositeChangeToken()
+        {
+            var changeTokens = new IChangeToken[_actionDescriptorChangeProviders.Length];
+            for (var i = 0; i < _actionDescriptorChangeProviders.Length; i++)
+            {
+                changeTokens[i] = _actionDescriptorChangeProviders[i].GetChangeToken();
+            }
+
+            return new CompositeChangeToken(changeTokens);
         }
 
         /// <summary>
@@ -37,34 +61,30 @@ public ActionDescriptorCollection ActionDescriptors
             {
                 if (_collection == null)
                 {
-                    _collection = GetCollection();
+                    UpdateCollection();
                 }
 
                 return _collection;
             }
         }
 
-        private ActionDescriptorCollection GetCollection()
+        private void UpdateCollection()
         {
-            var providers =
-                _serviceProvider.GetServices<IActionDescriptorProvider>()
-                                .OrderBy(p => p.Order)
-                                .ToArray();
-
             var context = new ActionDescriptorProviderContext();
 
-            foreach (var provider in providers)
+            for (var i = 0; i < _actionDescriptorProviders.Length; i++)
             {
-                provider.OnProvidersExecuting(context);
+                _actionDescriptorProviders[i].OnProvidersExecuting(context);
             }
 
-            for (var i = providers.Length - 1; i >= 0; i--)
+            for (var i = _actionDescriptorProviders.Length - 1; i >= 0; i--)
             {
-                providers[i].OnProvidersExecuted(context);
+                _actionDescriptorProviders[i].OnProvidersExecuted(context);
             }
 
-            return new ActionDescriptorCollection(
-                new ReadOnlyCollection<ActionDescriptor>(context.Results), 0);
+            _collection = new ActionDescriptorCollection(
+                new ReadOnlyCollection<ActionDescriptor>(context.Results),
+                Interlocked.Increment(ref _version));
         }
     }
 }

src/Microsoft.AspNetCore.Mvc.Core/Internal/CompositeChangeToken.cs

@@ -0,0 +1,85 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.Extensions.Primitives;
+
+namespace Microsoft.AspNetCore.Mvc.Internal
+{
+    internal class CompositeChangeToken : IChangeToken
+    {
+        public CompositeChangeToken(IList<IChangeToken> changeTokens)
+        {
+            if (changeTokens == null)
+            {
+                throw new ArgumentNullException(nameof(changeTokens));
+            }
+
+            ChangeTokens = changeTokens;
+        }
+
+        public IList<IChangeToken> ChangeTokens { get; }
+
+        public IDisposable RegisterChangeCallback(Action<object> callback, object state)
+        {
+            var disposables = new IDisposable[ChangeTokens.Count];
+            for (var i = 0; i < ChangeTokens.Count; i++)
+            {
+                var disposable = ChangeTokens[i].RegisterChangeCallback(callback, state);
+                disposables[i] = disposable;
+            }
+            return new CompositeDisposable(disposables);
+        }
+
+        public bool HasChanged
+        {
+            get
+            {
+                for (var i = 0; i < ChangeTokens.Count; i++)
+                {
+                    if (ChangeTokens[i].HasChanged)
+                    {
+                        return true;
+                    }
+                }
+
+                return false;
+            }
+        }
+
+        public bool ActiveChangeCallbacks
+        {
+            get
+            {
+                for (var i = 0; i < ChangeTokens.Count; i++)
+                {
+                    if (ChangeTokens[i].ActiveChangeCallbacks)
+                    {
+                        return true;
+                    }
+                }
+
+                return false;
+            }
+        }
+
+        private class CompositeDisposable : IDisposable
+        {
+            private readonly IDisposable[] _disposables;
+
+            public CompositeDisposable(IDisposable[] disposables)
+            {
+                _disposables = disposables;
+            }
+
+            public void Dispose()
+            {
+                for (var i = 0; i < _disposables.Length; i++)
+                {
+                    _disposables[i].Dispose();
+                }
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.Core.Test/Infrastructure/DefaultActionSelectorTests.cs

@@ -657,17 +657,9 @@ public void ActionNameAttribute_DifferentActionName_UsesActionNameFromActionName
         private ControllerActionDescriptor InvokeActionSelector(RouteContext context)
         {
             var actionDescriptorProvider = GetActionDescriptorProvider();
-
-            var serviceContainer = new ServiceCollection();
-            var list = new List<IActionDescriptorProvider>()
-            {
-                actionDescriptorProvider,
-            };
-
-            serviceContainer.AddSingleton(typeof(IEnumerable<IActionDescriptorProvider>), list);
-
             var actionDescriptorCollectionProvider = new ActionDescriptorCollectionProvider(
-                serviceContainer.BuildServiceProvider());
+                new[] { actionDescriptorProvider },
+                Enumerable.Empty<IActionDescriptorChangeProvider>());
             var decisionTreeProvider = new ActionSelectorDecisionTreeProvider(actionDescriptorCollectionProvider);
 
             var actionConstraintProviders = new[]
@@ -827,8 +819,9 @@ private static ActionDescriptor CreateAction(string area, string controller, str
 
         private static ActionConstraintCache GetActionConstraintCache(IActionConstraintProvider[] actionConstraintProviders = null)
         {
-            var services = new ServiceCollection().BuildServiceProvider();
-            var descriptorProvider = new ActionDescriptorCollectionProvider(services);
+            var descriptorProvider = new ActionDescriptorCollectionProvider(
+                Enumerable.Empty<IActionDescriptorProvider>(),
+                Enumerable.Empty<IActionDescriptorChangeProvider>());
             return new ActionConstraintCache(descriptorProvider, actionConstraintProviders.AsEnumerable() ?? new List<IActionConstraintProvider>());
         }
 

test/Microsoft.AspNetCore.Mvc.Core.Test/Internal/ActionConstraintCacheTest.cs

@@ -2,9 +2,12 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Linq;
 using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Abstractions;
 using Microsoft.AspNetCore.Mvc.ActionConstraints;
 using Microsoft.AspNetCore.Mvc.Controllers;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.Extensions.DependencyInjection;
 using Xunit;
 
@@ -156,8 +159,9 @@ private static IServiceProvider CreateServices()
 
         private static ActionConstraintCache CreateCache(params IActionConstraintProvider[] providers)
         {
-            var services = CreateServices();
-            var descriptorProvider = new ActionDescriptorCollectionProvider(services);
+            var descriptorProvider = new ActionDescriptorCollectionProvider(
+                Enumerable.Empty<IActionDescriptorProvider>(),
+                Enumerable.Empty<IActionDescriptorChangeProvider>());
             return new ActionConstraintCache(descriptorProvider, providers);
         }
     }