First commit

.gitignore

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+/[Bb]in/
+/[Oo]bj/
+/[Bb]uild/

.vscode/launch.json

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+{
+	// Use IntelliSense to learn about possible attributes.
+	// Hover to view descriptions of existing attributes.
+	// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+	"version": "0.2.0",
+	"configurations": [
+        {
+            "name": ".NET Core Launch (console)",
+            "type": "coreclr",
+            "request": "launch",
+            "preLaunchTask": "build",
+            "program": "${workspaceFolder}/bin/Debug/net6.0/MessageBus.exe",
+            "args": [],
+            "cwd": "${workspaceFolder}",
+            "stopAtEntry": false,
+            "console": "internalConsole"
+        },
+    ],
+}

.vscode/settings.json

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+{
+	"dotnet.defaultSolution": "MessageBus.sln"
+}

.vscode/tasks.json

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+{
+    "tasks": [
+        {
+            "label": "build",
+            "command": "dotnet",
+            "type": "process",
+            "args": [
+                "build",
+                "${workspaceFolder}/MessageBus.sln"
+            ],
+            "problemMatcher": "$msCompile"
+        }
+    ]
+}

Example/Example.cs

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+//------------------------------------------------------------------------------
+// MIT License
+//
+// Copyright (c) 2024 Tobias Barendt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//------------------------------------------------------------------------------
+
+public class Example
+{
+	//--------------------------------------------------------------------------
+	// Messages
+	public delegate void ExampleMessage();
+	public delegate void ExampleArguments(int x, int y);
+
+	//--------------------------------------------------------------------------
+	// Constructor
+	//--------------------------------------------------------------------------
+	public Example()
+	{
+		// Example of how to use it unscoped
+		UnscopedExample();
+
+		// Example on how to use it with a scope
+		ScopedExample();
+
+
+	}
+
+	//--------------------------------------------------------------------------
+	// UnscopedExample
+	//--------------------------------------------------------------------------
+	private void UnscopedExample()
+	{
+		//----------------------------------------------------------------------
+		// Subscribe to a few messages
+		MessageBus.Subscribe<ExampleMessage>(OnExampleMessage);
+		MessageBus.Subscribe<ExampleArguments>(OnExampleArguments);
+
+
+		//----------------------------------------------------------------------
+		// Dispatch messages
+		MessageBus.Dispatch<ExampleMessage>();
+		MessageBus.Dispatch<ExampleArguments>(100, 200);
+
+		//----------------------------------------------------------------------
+		// Remove subscriptions
+		MessageBus.Unsubscribe<ExampleMessage>(OnExampleMessage);
+		MessageBus.Unsubscribe<ExampleArguments>(OnExampleArguments);
+	}
+
+
+	//--------------------------------------------------------------------------
+	// ScopedExample
+	//--------------------------------------------------------------------------
+	private void ScopedExample()
+	{
+		//----------------------------------------------------------------------
+		// Subscribe to a few messages
+		MessageBus.Subscribe<ExampleMessage>("ExampleScope", OnExampleMessage);
+		MessageBus.Subscribe<ExampleArguments>("ExampleScope", OnExampleArguments);
+
+
+		//----------------------------------------------------------------------
+		// Dispatch messages
+		var scopedDispatcher = MessageBus.GetDispatcher("ExampleScope");
+
+		scopedDispatcher.Dispatch<ExampleMessage>();
+		scopedDispatcher.Dispatch<ExampleArguments>(64, 128);
+
+		//----------------------------------------------------------------------
+		// Remove subscriptions
+		MessageBus.Unsubscribe<ExampleMessage>("ExampleScope", OnExampleMessage);
+		MessageBus.Unsubscribe<ExampleArguments>("ExampleScope", OnExampleArguments);
+	}
+
+	//--------------------------------------------------------------------------
+	// OnExampleMessage
+	//--------------------------------------------------------------------------
+	private void OnExampleMessage()
+	{
+		Console.WriteLine("OnExampleMessage");
+	}
+
+	//--------------------------------------------------------------------------
+	// OnExampleArguments
+	//--------------------------------------------------------------------------
+	private void OnExampleArguments(int x, int y)
+	{
+		Console.WriteLine("ExampleArguments with " + x + " and " + y);
+	}
+}

MessageBus.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

MessageBus.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.30114.105
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MessageBus", "MessageBus.csproj", "{AC802790-5432-4DFD-B9E0-FB66DA790C92}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{AC802790-5432-4DFD-B9E0-FB66DA790C92}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{AC802790-5432-4DFD-B9E0-FB66DA790C92}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{AC802790-5432-4DFD-B9E0-FB66DA790C92}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{AC802790-5432-4DFD-B9E0-FB66DA790C92}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal

MessageBus/MessageBus.cs

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+//------------------------------------------------------------------------------
+// MIT License
+//
+// Copyright (c) 2024 Tobias Barendt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//------------------------------------------------------------------------------
+using System.Collections.Generic;
+using System.Diagnostics;
+
+//------------------------------------------------------------------------------
+// MessageBus
+//
+// The message bus is a central point for communication between different parts
+// of the application. It is used to decouple different parts of the application
+// and to allow for a more modular design.
+//
+public class MessageBus
+{
+	//--------------------------------------------------------------------------
+	// Singleton instance
+	private static MessageBus instance = new MessageBus();
+
+	//--------------------------------------------------------------------------
+	// Message Scopes
+	private Dictionary<string, MessageDispatcher> m_scopes = new();
+
+	//--------------------------------------------------------------------------
+	// GetDispatcher
+	//
+	// Returns the message dispatcher for the given scope. IF scoped does not 
+	// already exist it will be created.
+	//
+	//--------------------------------------------------------------------------
+	public static MessageDispatcher GetDispatcher() => instance.Internal_GetDispatcher("");
+	public static MessageDispatcher GetDispatcher(string scope) => instance.Internal_GetDispatcher(scope);
+	private MessageDispatcher Internal_GetDispatcher(string scope)
+	{
+		if(m_scopes.TryGetValue(scope, out var dispatcher))
+			return dispatcher;
+
+		m_scopes[scope] = new MessageDispatcher(scope);
+		return m_scopes[scope];
+	}
+	//--------------------------------------------------------------------------
+	// Dispatch
+	//
+	// Unscoped dispatch, will dispatch to all unscoped subscribers
+	// Use GetDispatcher for scoped dispatching
+	//
+	//--------------------------------------------------------------------------
+	public static void Dispatch<MessageType>(params object[] args) where MessageType : System.Delegate => instance.Internal_DispatchEvent(typeof(MessageType).GetHashCode(), args);
+	public static void Dispatch(System.Type messageType, params object[] args) => instance.Internal_DispatchEvent(messageType.GetHashCode(), args);
+	private void Internal_DispatchEvent(int type, params object[] args)
+	{
+		if(!m_scopes.ContainsKey(""))Internal_GetDispatcher("");
+		m_scopes[""].Dispatch(type, args);
+	}
+
+	//--------------------------------------------------------------------------
+	// Subscribe
+	//--------------------------------------------------------------------------
+	public static void Subscribe<MessageType>(MessageType subscriber) where MessageType : System.Delegate => instance.Internal_Subscribe("", subscriber);
+	public static void Subscribe<MessageType>(string scope, MessageType subscriber) where MessageType : System.Delegate => instance.Internal_Subscribe(scope, subscriber);
+	private void Internal_Subscribe<MessageType>(string scope, MessageType subscriber) where MessageType : System.Delegate
+	{
+		if(!m_scopes.ContainsKey(scope))Internal_GetDispatcher(scope);
+		m_scopes[scope].Subscribe(subscriber);
+	}
+
+	//--------------------------------------------------------------------------
+	// Unsubscribe
+	//--------------------------------------------------------------------------
+	public static void Unsubscribe<MessageType>(MessageType subscriber) where MessageType : System.Delegate => instance.Internal_Unsubscribe("", subscriber);
+	public static void Unsubscribe<MessageType>(string scope, MessageType subscriber) where MessageType : System.Delegate => instance.Internal_Unsubscribe(scope, subscriber);
+	private void Internal_Unsubscribe<MessageType>(string scope, MessageType subscriber) where MessageType : System.Delegate
+	{
+		if(!m_scopes.ContainsKey(scope))return ;
+		m_scopes[scope].Unsubscribe(subscriber);
+	}
+}
+
+//------------------------------------------------------------------------------
+// IMessageDispatcher
+//
+// Interface for the message dispatcher, handy for making proxy dispatchers.
+//
+//------------------------------------------------------------------------------
+public interface IMessageDispatcher
+{
+	public void Dispatch<MessageType>(params object[] args) where MessageType : System.Delegate;
+	public void Dispatch(System.Type messageType, params object[] args);
+	public void Subscribe<MessageType>(MessageType subscriber) where MessageType : System.Delegate;
+	public void Unsubscribe<MessageType>(MessageType subscriber) where MessageType : System.Delegate;
+}
+
+//------------------------------------------------------------------------------
+// MessageDispatcher
+//
+// The message dispatcher is used to dispatch messages to the correct handlers.
+//
+//------------------------------------------------------------------------------
+public class MessageDispatcher : IMessageDispatcher
+{
+	//--------------------------------------------------------------------------
+	// Properties
+	public string Scope {get; private set;}
+
+	//--------------------------------------------------------------------------
+	// Subscribers
+	private Dictionary<int, HashSet<System.Delegate>> m_subscribers = new();
+
+	//--------------------------------------------------------------------------
+	// Cache
+	private List<System.Delegate> m_delegateList = new(8);
+
+	//--------------------------------------------------------------------------
+	// Constructor
+	//--------------------------------------------------------------------------
+	public MessageDispatcher(string scope)
+	{
+		Scope = scope;
+	}
+
+	//--------------------------------------------------------------------------
+	// Subscribe
+	//--------------------------------------------------------------------------
+	public void Subscribe<MessageType>(MessageType subscriber) where MessageType : System.Delegate
+	{
+		// Find message type set
+		int type = subscriber.GetType().GetHashCode();
+		if(!m_subscribers.TryGetValue(type, out var messageSet))
+		{
+			// First time we see this message type, create a new set
+			messageSet = new HashSet<System.Delegate>();
+			m_subscribers[type] = messageSet;
+		}
+
+		// Add listener
+		Debug.Assert(!messageSet.Contains(subscriber as System.Delegate), "Listener added twice! [" + subscriber.GetType() + "]");
+		messageSet.Add(subscriber as System.Delegate);
+	}
+
+	//--------------------------------------------------------------------------
+	// Unsubscribe
+	//--------------------------------------------------------------------------
+	public void Unsubscribe<MessageType>(MessageType subscriber) where MessageType : System.Delegate
+	{
+		// Find message type set
+		int type = subscriber.GetType().GetHashCode();
+		if(m_subscribers.TryGetValue(type, out var messageSet))
+		{
+			messageSet.Remove(subscriber as System.Delegate);
+			if(messageSet.Count == 0)
+				m_subscribers.Remove(type);
+		}
+	}
+
+	//--------------------------------------------------------------------------
+	// DispatchEvent
+	//--------------------------------------------------------------------------
+	public void Dispatch<MessageType>(params object[] args) where MessageType : System.Delegate => Internal_DispatchEvent(typeof(MessageType).GetHashCode(), args);
+	public void Dispatch(System.Type messageType, params object[] args) => Internal_DispatchEvent(messageType.GetHashCode(), args);
+	public void Dispatch(int type, params object[] args) => Internal_DispatchEvent(type, args);
+	private void Internal_DispatchEvent(int type, params object[] args)
+	{
+		if(m_subscribers.TryGetValue(type, out var messageSet))
+		{
+			if(messageSet.Count > 0)
+			{
+				m_delegateList.Clear();
+				foreach(System.Delegate dg in messageSet)m_delegateList.Add(dg);
+
+				for(int i = 0; i < m_delegateList.Count; i++)
+				{
+					try
+					{
+						m_delegateList[i].Method.Invoke(m_delegateList[i].Target, args);
+					}
+					catch(System.Exception e)
+					{
+						Debug.Assert(false, "Error dispatching message: " + e.Message);
+					}
+				}
+			}
+		}
+	}
+}