From 93aa697347e47141d6b15bdbeb6fdf3055dfbcc0 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Sun, 13 Apr 2025 17:36:43 +0300
Subject: [PATCH] Support RAII-wrapping the execution of an ECS system into
 some context (e.g. for profiling)

---
 libs/ecs/include/psemek/ecs/dispatcher.hpp | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/libs/ecs/include/psemek/ecs/dispatcher.hpp b/libs/ecs/include/psemek/ecs/dispatcher.hpp
index b534413e..a51aaa39 100644
--- a/libs/ecs/include/psemek/ecs/dispatcher.hpp
+++ b/libs/ecs/include/psemek/ecs/dispatcher.hpp
@@ -7,6 +7,19 @@
 namespace psemek::ecs
 {
 
+	namespace detail
+	{
+
+		struct default_context_factory
+		{
+			int operator()() const noexcept
+			{
+				return 0;
+			}
+		};
+
+	}
+
 	struct dispatcher
 	{
 		dispatcher() = default;
@@ -42,12 +55,14 @@ namespace psemek::ecs
 			});
 		}
 
-		template <typename Event, typename ... Components, typename System>
-		void system(System system)
+		template <typename Event, typename ... Components, typename System, typename ContextFactory = detail::default_context_factory>
+		void system(System system, ContextFactory && context_factory = ContextFactory{})
 		{
-			handlers_[Event::uuid()].push_back([system = std::move(system), this, cache = container_->cache<Components...>()](void const * event_ptr) mutable {
+			handlers_[Event::uuid()].push_back([system = std::move(system), this, cache = container_->cache<Components...>(), context_factory = std::move(context_factory)](void const * event_ptr) mutable {
 				auto const & event = *reinterpret_cast<Event const *>(event_ptr);
 
+				[[maybe_unused]] auto context = context_factory();
+
 				container_->apply<Components...>([&]<typename ... FilteredComponents>(ecs::container & container, ecs::handle entity, FilteredComponents & ... filtered_components){
 					if constexpr (std::invocable<System, Event const &, ecs::container &, handle, FilteredComponents & ...>)
 					{