perf(CommunityToolkit.Mvvm): use System.Threading.Lock (NET9+) and FrozenDictionary (NET8+)

src/CommunityToolkit.Mvvm/CommunityToolkit.Mvvm.csproj

@@ -1,7 +1,10 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1;net8.0;net8.0-windows10.0.17763.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net8.0;net8.0-windows10.0.17763.0;net10.0;net10.0-windows10.0.17763.0</TargetFrameworks>
+    <!-- C# 13 enables the optimized lock statement for System.Threading.Lock (NET9+), where
+         the compiler emits Lock.EnterScope() instead of Monitor.Enter/Exit for reduced overhead. -->
+    <LangVersion>13.0</LangVersion>
   </PropertyGroup>
 
   <!--

src/CommunityToolkit.Mvvm/ComponentModel/ObservableValidator.cs

@@ -5,6 +5,9 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+#if NET8_0_OR_GREATER
+using System.Collections.Frozen;
+#endif
 using System.ComponentModel;
 using System.ComponentModel.DataAnnotations;
 using System.Diagnostics.CodeAnalysis;
@@ -36,7 +39,11 @@ public abstract class ObservableValidator : ObservableObject, INotifyDataErrorIn
     /// so we need to replicate the same logic to retrieve the right display name for properties to validate and update that
     /// property manually right before passing the context to <see cref="Validator"/> and proceed with the normal functionality.
     /// </remarks>
+#if NET8_0_OR_GREATER
+    private static readonly ConditionalWeakTable<Type, FrozenDictionary<string, string>> DisplayNamesMap = new();
+#else
     private static readonly ConditionalWeakTable<Type, Dictionary<string, string>> DisplayNamesMap = new();
+#endif
 
     /// <summary>
     /// The cached <see cref="PropertyChangedEventArgs"/> for <see cref="HasErrors"/>.
@@ -807,6 +814,23 @@ private void ClearErrorsForProperty(string propertyName)
     [RequiresUnreferencedCode("The type of the current instance cannot be statically discovered.")]
     private string GetDisplayNameForProperty(string propertyName)
     {
+#if NET8_0_OR_GREATER
+        static FrozenDictionary<string, string> GetDisplayNames(Type type)
+        {
+            Dictionary<string, string> displayNames = new();
+
+            foreach (PropertyInfo property in type.GetProperties(BindingFlags.Instance | BindingFlags.Public))
+            {
+                if (property.GetCustomAttribute<DisplayAttribute>() is DisplayAttribute attribute &&
+                    attribute.GetName() is string displayName)
+                {
+                    displayNames.Add(property.Name, displayName);
+                }
+            }
+
+            return displayNames.ToFrozenDictionary();
+        }
+#else
         static Dictionary<string, string> GetDisplayNames(Type type)
         {
             Dictionary<string, string> displayNames = new();
@@ -822,6 +846,7 @@ static Dictionary<string, string> GetDisplayNames(Type type)
 
             return displayNames;
         }
+#endif
 
         // This method replicates the logic of DisplayName and GetDisplayName from the
         // ValidationContext class. See the original source in the BCL for more details.

src/CommunityToolkit.Mvvm/Messaging/Internals/System/Runtime.CompilerServices/ConditionalWeakTable2{TKey,TValue}.ZeroAlloc.cs

@@ -29,7 +29,11 @@ internal sealed class ConditionalWeakTable2<TKey, TValue>
     /// <summary>
     /// This lock protects all mutation of data in the table. Readers do not take this lock.
     /// </summary>
-    private readonly object lockObject;
+#if NET9_0_OR_GREATER
+    private readonly Lock lockObject = new();
+#else
+    private readonly object lockObject = new();
+#endif
 
     /// <summary>
     /// The actual storage for the table; swapped out as the table grows.
@@ -41,7 +45,6 @@ internal sealed class ConditionalWeakTable2<TKey, TValue>
     /// </summary>
     public ConditionalWeakTable2()
     {
-        this.lockObject = new object();
         this.container = new Container(this);
     }
 
@@ -138,7 +141,11 @@ public Enumerator GetEnumerator()
         // invoked. This is fine in this specific scenario because we're the only users of the enumerators so
         // there's no concern about blocking other threads while enumerating. So here we just preemptively take
         // a lock for the entire lifetime of the enumerator, and just release it once once we're done.
+#if NET9_0_OR_GREATER
+        this.lockObject.Enter();
+#else
         Monitor.Enter(this.lockObject);
+#endif
 
         return new(this);
     }
@@ -204,7 +211,11 @@ public Enumerator(ConditionalWeakTable2<TKey, TValue> table)
         public void Dispose()
         {
             // Release the lock
+#if NET9_0_OR_GREATER
+            this.table.lockObject.Exit();
+#else
             Monitor.Exit(this.table.lockObject);
+#endif
 
             this.table = null!;
 

src/CommunityToolkit.Mvvm/Messaging/StrongReferenceMessenger.cs

@@ -95,6 +95,18 @@ public sealed class StrongReferenceMessenger : IMessenger
     /// </remarks>
     private readonly Dictionary2<Type2, IMapping> typesMap = new();
 
+#if NET9_0_OR_GREATER
+    /// <summary>
+    /// The <see cref="Lock"/> used to synchronize access to <see cref="recipientsMap"/>.
+    /// </summary>
+    private readonly Lock recipientsMapLock = new();
+#else
+    /// <summary>
+    /// The lock object used to synchronize access to <see cref="recipientsMap"/>.
+    /// </summary>
+    private readonly object recipientsMapLock = new();
+#endif
+
     /// <summary>
     /// Gets the default <see cref="StrongReferenceMessenger"/> instance.
     /// </summary>
@@ -108,7 +120,7 @@ public bool IsRegistered<TMessage, TToken>(object recipient, TToken token)
         ArgumentNullException.ThrowIfNull(recipient);
         ArgumentNullException.For<TToken>.ThrowIfNull(token);
 
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             if (typeof(TToken) == typeof(Unit))
             {
@@ -171,7 +183,7 @@ private void Register<TMessage, TToken>(object recipient, TToken token, MessageH
        where TMessage : class
        where TToken : IEquatable<TToken>
     {
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             Recipient key = new(recipient);
             IMapping mapping;
@@ -227,7 +239,7 @@ public void UnregisterAll(object recipient)
     {
         ArgumentNullException.ThrowIfNull(recipient);
 
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             // If the recipient has no registered messages at all, ignore
             Recipient key = new(recipient);
@@ -399,7 +411,7 @@ public void Unregister<TMessage, TToken>(object recipient, TToken token)
         ArgumentNullException.ThrowIfNull(recipient);
         ArgumentNullException.For<TToken>.ThrowIfNull(token);
 
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             if (typeof(TToken) == typeof(Unit))
             {
@@ -500,7 +512,7 @@ public TMessage Send<TMessage, TToken>(TMessage message, TToken token)
         Span<object?> pairs;
         int i = 0;
 
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             if (typeof(TToken) == typeof(Unit))
             {
@@ -618,7 +630,7 @@ void IMessenger.Cleanup()
     /// <inheritdoc/>
     public void Reset()
     {
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             this.recipientsMap.Clear();
             this.typesMap.Clear();
@@ -856,3 +868,4 @@ private static void ThrowInvalidOperationExceptionForDuplicateRegistration()
         throw new InvalidOperationException("The target recipient has already subscribed to the target message.");
     }
 }
+

src/CommunityToolkit.Mvvm/Messaging/WeakReferenceMessenger.cs

@@ -62,6 +62,18 @@ public sealed class WeakReferenceMessenger : IMessenger
     /// </summary>
     private readonly Dictionary2<Type2, ConditionalWeakTable2<object, object?>> recipientsMap = new();
 
+#if NET9_0_OR_GREATER
+    /// <summary>
+    /// The <see cref="Lock"/> used to synchronize access to <see cref="recipientsMap"/>.
+    /// </summary>
+    private readonly Lock recipientsMapLock = new();
+#else
+    /// <summary>
+    /// The lock object used to synchronize access to <see cref="recipientsMap"/>.
+    /// </summary>
+    private readonly object recipientsMapLock = new();
+#endif
+
     /// <summary>
     /// Initializes a new instance of the <see cref="WeakReferenceMessenger"/> class.
     /// </summary>
@@ -98,7 +110,7 @@ public bool IsRegistered<TMessage, TToken>(object recipient, TToken token)
         ArgumentNullException.ThrowIfNull(recipient);
         ArgumentNullException.For<TToken>.ThrowIfNull(token);
 
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             Type2 type2 = new(typeof(TMessage), typeof(TToken));
 
@@ -168,7 +180,7 @@ private void Register<TMessage, TToken>(object recipient, TToken token, MessageH
         where TMessage : class
         where TToken : IEquatable<TToken>
     {
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             Type2 type2 = new(typeof(TMessage), typeof(TToken));
 
@@ -209,7 +221,7 @@ public void UnregisterAll(object recipient)
     {
         ArgumentNullException.ThrowIfNull(recipient);
 
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             Dictionary2<Type2, ConditionalWeakTable2<object, object?>>.Enumerator enumerator = this.recipientsMap.GetEnumerator();
 
@@ -237,7 +249,7 @@ public void UnregisterAll<TToken>(object recipient, TToken token)
             throw new NotImplementedException();
         }
 
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             Dictionary2<Type2, ConditionalWeakTable2<object, object?>>.Enumerator enumerator = this.recipientsMap.GetEnumerator();
 
@@ -265,7 +277,7 @@ public void Unregister<TMessage, TToken>(object recipient, TToken token)
         ArgumentNullException.ThrowIfNull(recipient);
         ArgumentNullException.For<TToken>.ThrowIfNull(token);
 
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             Type2 type2 = new(typeof(TMessage), typeof(TToken));
 
@@ -296,7 +308,7 @@ public TMessage Send<TMessage, TToken>(TMessage message, TToken token)
         ArrayPoolBufferWriter<object?> bufferWriter;
         int i = 0;
 
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             Type2 type2 = new(typeof(TMessage), typeof(TToken));
 
@@ -422,7 +434,7 @@ internal static void SendAll<TMessage>(ReadOnlySpan<object?> pairs, int i, TMess
     /// <inheritdoc/>
     public void Cleanup()
     {
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             CleanupWithoutLock();
         }
@@ -431,7 +443,7 @@ public void Cleanup()
     /// <inheritdoc/>
     public void Reset()
     {
-        lock (this.recipientsMap)
+        lock (this.recipientsMapLock)
         {
             this.recipientsMap.Clear();
         }
@@ -443,7 +455,20 @@ public void Reset()
     /// </summary>
     private void CleanupWithNonBlockingLock()
     {
-        object lockObject = this.recipientsMap;
+#if NET9_0_OR_GREATER
+        if (this.recipientsMapLock.TryEnter())
+        {
+            try
+            {
+                CleanupWithoutLock();
+            }
+            finally
+            {
+                this.recipientsMapLock.Exit();
+            }
+        }
+#else
+        object lockObject = this.recipientsMapLock;
         bool lockTaken = false;
 
         try
@@ -462,6 +487,7 @@ private void CleanupWithNonBlockingLock()
                 Monitor.Exit(lockObject);
             }
         }
+#endif
     }
 
     /// <summary>
@@ -546,3 +572,4 @@ private static void ThrowInvalidOperationExceptionForDuplicateRegistration()
         throw new InvalidOperationException("The target recipient has already subscribed to the target message.");
     }
 }
+

tests/CommunityToolkit.Mvvm.Roslyn5000.UnitTests/CommunityToolkit.Mvvm.Roslyn5000.UnitTests.csproj

@@ -1,7 +1,7 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net472;net8.0;net9.0</TargetFrameworks>
+    <TargetFrameworks>net472;net8.0;net9.0;net10.0</TargetFrameworks>
     <LangVersion>14.0</LangVersion>
     <SuppressTfmSupportBuildWarnings>true</SuppressTfmSupportBuildWarnings>
     <DefineConstants>$(DefineConstants);ROSLYN_4_12_0_OR_GREATER;ROSLYN_5_0_0_OR_GREATER</DefineConstants>
@@ -32,4 +32,4 @@
 
   <Import Project="..\CommunityToolkit.Mvvm.UnitTests\CommunityToolkit.Mvvm.UnitTests.projitems" Label="Shared" />
 
-</Project>
+</Project>