Merge branch 'main' of https://github.com/SimonCropp/Polyfill

apiCount.include.md

@@ -1 +1 @@
-**API count: 434**
+**API count: 435**

api_list.include.md

@@ -490,6 +490,11 @@
  * `bool TryParse(string?, IFormatProvider?, byte)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.byte.tryparse#system-byte-tryparse(system-string-system-iformatprovider-system-byte@))
 
 
+#### DelegatePolyfill
+
+ * `InvocationListEnumerator<TDelegate> EnumerateInvocationList<TDelegate>(TDelegate?) where TDelegate : Delegate` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.delegate.enumerateinvocationlist)
+
+
 #### GuidPolyfill
 
  * `Guid CreateVersion7()` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.guid.createversion7#system-guid-createversion7)

readme.md

@@ -12,7 +12,7 @@ The package targets `netstandard2.0` and is designed to support the following ru
  * `net5.0`, `net6.0`, `net7.0`, `net8.0`, `net9.0`
 
 
-**API count: 434**<!-- singleLineInclude: apiCount. path: /apiCount.include.md -->
+**API count: 435**<!-- singleLineInclude: apiCount. path: /apiCount.include.md -->
 
 
 **See [Milestones](../../milestones?state=closed) for release notes.**
@@ -959,6 +959,11 @@ The class `Polyfill` includes the following extension methods:
  * `bool TryParse(string?, IFormatProvider?, byte)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.byte.tryparse#system-byte-tryparse(system-string-system-iformatprovider-system-byte@))
 
 
+#### DelegatePolyfill
+
+ * `InvocationListEnumerator<TDelegate> EnumerateInvocationList<TDelegate>(TDelegate?) where TDelegate : Delegate` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.delegate.enumerateinvocationlist)
+
+
 #### GuidPolyfill
 
  * `Guid CreateVersion7()` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.guid.createversion7#system-guid-createversion7)

src/ApiBuilderTests/BuildApiTest.cs

@@ -34,6 +34,7 @@ public void RunWithRoslyn()
         WriteHelper(types, "RegexPolyfill", writer, ref count);
         WriteHelper(types, "StringPolyfill", writer, ref count);
         WriteHelper(types, "BytePolyfill", writer, ref count);
+        WriteHelper(types, "DelegatePolyfill", writer, ref count);
         WriteHelper(types, "GuidPolyfill", writer, ref count);
         WriteHelper(types, "DateTimePolyfill", writer, ref count);
         WriteHelper(types, "DateTimeOffsetPolyfill", writer, ref count);

src/Polyfill/DelegatePolyfill.cs

@@ -0,0 +1,65 @@
+// <auto-generated />
+
+
+#pragma warning disable
+
+namespace Polyfills;
+
+using System;
+using System.ComponentModel;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+
+[ExcludeFromCodeCoverage]
+[DebuggerNonUserCode]
+#if PolyPublic
+public
+#endif
+static partial class DelegatePolyfill
+{
+    /// <summary>
+    /// Gets an enumerator for the invocation targets of this delegate.
+    /// </summary>
+    //Link: https://learn.microsoft.com/en-us/dotnet/api/system.delegate.enumerateinvocationlist
+#if NET9_0_OR_GREATER
+    public static Delegate.InvocationListEnumerator<TDelegate> EnumerateInvocationList<TDelegate>(TDelegate? target) where TDelegate : Delegate =>
+        Delegate.EnumerateInvocationList(target);
+#else
+    public static InvocationListEnumerator<TDelegate> EnumerateInvocationList<TDelegate>(TDelegate? target) where TDelegate : Delegate =>
+        new InvocationListEnumerator<TDelegate>(target);
+
+    /// <summary>
+    /// Provides an enumerator for the invocation list of a delegate.
+    /// </summary>
+    /// <typeparam name="TDelegate">Delegate type being enumerated.</typeparam>
+    public struct InvocationListEnumerator<TDelegate>
+        where TDelegate : Delegate
+    {
+        Delegate[] delegates;
+        int index = -1;
+
+        internal InvocationListEnumerator(Delegate target) =>
+            delegates = target.GetInvocationList();
+
+        public TDelegate Current { get; private set; }
+
+        public bool MoveNext()
+        {
+            int index = this.index + 1;
+            if (index == delegates.Length)
+            {
+                return false;
+            }
+
+            Current = (TDelegate) delegates[index];
+            this.index = index;
+            return true;
+        }
+
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public InvocationListEnumerator<TDelegate> GetEnumerator() => this;
+    }
+#endif
+
+}

src/Tests/PolyfillTests_Delegate.cs

@@ -1,14 +1,14 @@
 partial class PolyfillTests
 {
-    public static event EventHandler? MyEvent;
+    public static event EventHandler? EventForHasSingleTarget;
 
     [Test]
     public void HasSingleTarget()
     {
-        MyEvent += Handler;
-        Assert.IsTrue(MyEvent.HasSingleTarget());
-        MyEvent += Handler;
-        Assert.IsFalse(MyEvent.HasSingleTarget());
+        EventForHasSingleTarget += Handler;
+        Assert.IsTrue(EventForHasSingleTarget.HasSingleTarget());
+        EventForHasSingleTarget += Handler;
+        Assert.IsFalse(EventForHasSingleTarget.HasSingleTarget());
         var action = () =>
         {
         };
@@ -20,4 +20,21 @@ public void HasSingleTarget()
     static void Handler(object? sender, EventArgs e)
     {
     }
+
+    public static event EventHandler? EventForEnumerateInvocationList;
+
+    [Test]
+    public void EnumerateInvocationList()
+    {
+        var count = 0;
+
+        EventForEnumerateInvocationList += (_, _) => count++;
+
+        foreach (var item in DelegatePolyfill.EnumerateInvocationList(EventForEnumerateInvocationList))
+        {
+            item(this, EventArgs.Empty);
+        }
+
+        Assert.AreEqual(1, count);
+    }
 }