Event flattening

JLChnToZ · Jun 4, 2023 · 2a3e315 · 2a3e315
1 parent 45e095a
commit 2a3e315
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Showing 2 changed files with 37 additions and 2 deletions.
diff --git a/JLChnToZ.CommonUtils.Dynamic/LimitlessEvent.cs b/JLChnToZ.CommonUtils.Dynamic/LimitlessEvent.cs
@@ -43,8 +43,8 @@ public override bool TryBinaryOperation(BinaryOperationBinder binder, object arg
                     targetDelegate = argDelegate;
                 else {
                     // Rewrap delegate to avoid type mismatch
-                    targetDelegate = Delegate.CreateDelegate(eventType, argDelegate, delegateType.GetMethod("Invoke"), false);
-                    if (targetDelegate == null) { // Failed to rewrap, possibly incorrect signature
+                    targetDelegate = argDelegate.ConvertAndFlatten(eventType);
+                    if (targetDelegate == null) {
                         result = null;
                         return false;
                     }

diff --git a/JLChnToZ.CommonUtils.Dynamic/Utilites.cs b/JLChnToZ.CommonUtils.Dynamic/Utilites.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq.Expressions;
 using System.Reflection;
 
@@ -105,6 +106,40 @@ public static MethodInfo GetUndelyRaiseMethod(this EventInfo eventInfo, out Dele
             }
             return raiseMethod;
         }
+
+        public static Delegate ConvertAndFlatten(this Delegate del, Type toType = null) {
+            if (del == null) return null;
+            if (toType == null) toType = del.GetType();
+            var entries = new Stack<Delegate>();
+            entries.Push(del);
+            del = null;
+            while (entries.Count > 0) {
+                var current = entries.Pop();
+                if (current == null) continue;
+                // Check if current delegate multi-cast and if so, flatten it
+                var list = current.GetInvocationList();
+                if (list.Length > 1) {
+                    // We do it in reverse order to preserve the order of the delegates
+                    for (int i = list.Length - 1; i >= 0; i--)
+                        entries.Push(list[i]);
+                    continue;
+                }
+                var target = current.Target;
+                var method = current.Method;
+                // Check if target is a delegate and if so, flatten it
+                if (target is Delegate subDelegate && method.Name == "Invoke") {
+                    list = subDelegate.GetInvocationList();
+                    for (int i = list.Length - 1; i >= 0; i--)
+                        entries.Push(list[i]);
+                    continue;
+                }
+                if (current.GetType() != toType)
+                    current = target == null ? Delegate.CreateDelegate(toType, method, false) :
+                        Delegate.CreateDelegate(toType, target, method, false);
+                del = Delegate.Combine(del, current);
+            }
+            return del;
+        }
     }
 
     internal enum MethodMatchLevel {