From 009498fae18df561452ffbfc799a8e8d95f1d52c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sascha=20K=C3=BChl?= <s.kuehl@tms-bonn.de>
Date: Fri, 17 Oct 2025 08:53:41 +0200
Subject: [PATCH] added type shortcuts in message_bus

---
 include/matador/utils/message_bus.hpp | 28 ++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/include/matador/utils/message_bus.hpp b/include/matador/utils/message_bus.hpp
index e1b43ee..c919c3b 100644
--- a/include/matador/utils/message_bus.hpp
+++ b/include/matador/utils/message_bus.hpp
@@ -179,6 +179,22 @@ class message_bus {
 public:
     using HandlerId = uint64_t; /**< Type alias for handler IDs. */
 
+    /**
+     * @brief Type alias for message filter functions.
+     * @tparam MessageType The type of message the filter operates on.
+     */
+    template<typename MessageType>
+    using Filter = std::function<bool(const MessageType&)>;
+
+    /**
+     * @brief Type alias for member function pointers used as message handlers.
+     * @tparam MessageType The type of message the handler processes.
+     * @tparam CallerClass The class that contains the member function.
+     */
+    template<typename MessageType, typename CallerClass>
+    using MemberHandler = void (CallerClass::*)(const MessageType&);
+
+
     /**
      * @brief Constructs a new message_bus object.
      */
@@ -194,7 +210,7 @@ public:
      */
     template<typename MessageType>
     subscription subscribe(std::function<void(const MessageType&)> handler,
-                           std::function<bool(const MessageType&)> filter = nullptr)
+                           Filter<MessageType> filter = nullptr)
     {
         auto id = next_id_.fetch_add(1, std::memory_order_relaxed);
         std::unique_lock writeLock(mutex_);
@@ -227,8 +243,9 @@ public:
      * @return A subscription object to manage the handler's registration.
      */
     template<typename MessageType, typename CallerClass>
-    subscription subscribe(CallerClass* instance, void (CallerClass::*memberFn)(const MessageType&),
-                           std::function<bool(const MessageType&)> filter = nullptr)
+    subscription subscribe(CallerClass* instance,
+                           MemberHandler<MessageType, CallerClass> memberFn,
+                           Filter<MessageType> filter = nullptr)
     {
         auto fn = [instance, memberFn](const MessageType& m) { (instance->*memberFn)(m); };
         return subscribe<MessageType>(std::function<void(const MessageType&)>(fn), std::move(filter));
@@ -245,8 +262,9 @@ public:
      * @return A subscription object to manage the handler's registration.
      */
     template<typename MessageType, typename CallerClass>
-    subscription subscribe(std::shared_ptr<CallerClass> instance, void (CallerClass::*memberFn)(const MessageType&),
-                           std::function<bool(const MessageType&)> filter = nullptr)
+    subscription subscribe(std::shared_ptr<CallerClass> instance,
+                           MemberHandler<MessageType, CallerClass> memberFn,
+                           Filter<MessageType> filter = nullptr)
     {
         std::weak_ptr<CallerClass> w = instance;
         auto handler = [w, memberFn](const MessageType& m) {