tmp

include/threepp/core/EventDispatcher.hpp

@@ -14,6 +14,15 @@
 
 namespace threepp {
 
+    namespace concepts {
+#if defined(__cpp_concepts) && (__cpp_concepts >= 201907L) 
+        template<typename TEvent>
+        concept Event = requires(TEvent e) {
+            { e.target } -> std::convertible_to<void*>;
+            { e.unsubscribe } -> std::convertible_to<bool>;
+        };
+#endif
+    }
 
     /// An event listener is just a function that takes an argument of type TEvent
     template<typename TEvent>
@@ -27,12 +36,16 @@ namespace threepp {
 
     /// Allows one to use the << to push subscriptions onto the vector
     inline
-    void operator<<(std::vector<Subscription>& subs, Subscription& sub) {
+    void operator<<(std::vector<Subscription>& subs, Subscription const & sub) {
         subs.push_back(sub);
     }
 
     /// Generic event dispatch class
     template <typename TEvent>
+#if defined(__cpp_concepts) && (__cpp_concepts >= 201907L) 
+    requires concepts::Event<TEvent>
+#endif
+    // C++20 (and later) code
     class TEventDispatcher {
     public:
         using EventListener = TEventListener<TEvent>;
@@ -69,6 +82,7 @@ namespace threepp {
             s.subscribeOnce([sub](auto&) {});
         }
 
+
         /// Send an event to all listeners.
         void send(TEvent & e){
             std::vector<size_t> toUnsubscribe;
@@ -83,6 +97,11 @@ namespace threepp {
                 listeners_.erase(id);
         }
 
+        /// Handle r-value versions of send
+        void send(TEvent && e) {
+            send(e);
+        }
+
         virtual ~TEventDispatcher() = default;
 
     private: