More work on State System

src/dawn/state/State.hpp

@@ -8,10 +8,44 @@
 #include "StateProperty.hpp"
 
 namespace Dawn {
+  template<typename ...A>
+  class StateOwnerEventLegacy : public IStateOwnerEventLegacy {
+    public:
+      IStateOwner *owner;
+      Event<A...> *event;
+      std::function<void(A...)> fn;
+
+      /**
+       * Function used to simply remove the event listener from the legacy
+       * event, does not deal with the state owner. 
+       */
+      void removeListener() override {
+        event->removeListener(this, &StateOwnerEventLegacy::callback);
+      }
+
+      /**
+       * Function that can be used to tear down this legacy event.
+       */
+      void teardown() override {
+        this->removeListener();
+        owner->_stateLegacyEventDisposed(this);
+      }
+
+      /**
+       * Callbaack method that is invoked by the legacy event.
+       * @param args Arguments received by legacy event.
+       */
+      void callback(A... args) {
+        this->fn(args...);
+      }
+  };
+
   class StateOwner : public IStateOwner {
     private:
       std::vector<IStateEvent*> eventsSubscribed;
-
+      std::vector<IStateOwnerEventLegacy*> eventLegacyBridge;
+  
+    public:
       /**
        * Called by the state event when it is disposing (before the StateOwner
        * itself is).
@@ -28,8 +62,25 @@ namespace Dawn {
           }
         }
       }
-  
-    public:
+
+      /**
+       * Called by legacy events when they are being disposed in a way that was
+       * not called by this state owner disposing.
+       * 
+       * @param evt Event that is being disposed.
+       */
+      void _stateLegacyEventDisposed(IStateOwnerEventLegacy *evt) override {
+        auto it = this->eventLegacyBridge.begin();
+        while(it != this->eventLegacyBridge.end()) {
+          if(*it == evt) {
+            this->eventLegacyBridge.erase(it);
+            break;
+          } else {
+            ++it;
+          }
+        }
+      }
+
       /**
        * Listen for changes to a state property and invoke the provided func
        * when the value is changed.
@@ -126,15 +177,55 @@ namespace Dawn {
 
         return listener.unsub;
       }
-      
-      
+    
+      /**
+       * Listen for callback of a legacy styled event. This will be removed in
+       * the future in favour of everything using State Events. This uses a lot
+       * more memory than the new state event listener.
+       * 
+       * @deprecated In favour of StateEvent<>
+       * @tparam F The type of the callback function.
+       * @tparam A Argument types for the event.
+       * @param fn Callback function to be invoked when the event is triggered.
+       * @param event Event that will be listened to.
+       */
+      template<typename F, typename... A>
+      std::function<void()> useEventLegacy(
+        F fn,
+        Event<A...> &event
+      ) {
+        // This is a legacy feature to make upgrading to the new useEffect a bit
+        // easier for me. For the time being I am just bodging this together to
+        // do what I need here.
+        auto bridge = new StateOwnerEventLegacy<A...>();
+        bridge->owner = this;
+        bridge->event = &event;
+        bridge->fn = fn;
+        event.addListener(bridge, &StateOwnerEventLegacy<A...>::callback);
+        eventLegacyBridge.push_back(bridge);
 
+        return std::bind([&](IStateOwnerEventLegacy *evt){
+          evt->teardown();
+        }, bridge);
+      }
+
+      /**
+       * State Owner teardown function. Mostly just used to remove any lingering
+       * useEffects or useEvents.
+       */
       virtual ~StateOwner() {
         auto it = this->eventsSubscribed.begin();
         while(it != this->eventsSubscribed.end()) {
           (*it)->_stateOwnerDestroyed(this);
           ++it;
         }
+
+        auto itBridge = this->eventLegacyBridge.begin();
+        while(itBridge != this->eventLegacyBridge.end()) {
+          (*itBridge)->removeListener();
+          delete *itBridge;
+          ++itBridge;
+        }
       }
   };
 }

src/dawn/state/StateEvent.hpp

@@ -4,31 +4,14 @@
 // https://opensource.org/licenses/MIT
 
 #pragma once
-#include "assert/assert.hpp"
-#include "event/Event.hpp"
+#include "StateInterfaces.hpp"
 
 namespace Dawn {
-  /** Forwarders / Fake Virtuals for other methods. */
   template<typename...A>
-  class StateEvent;
-  class IStateEvent;
-  class IStateOwner {
-    public:
-      virtual void _stateEventDisposed(IStateEvent *evt) = 0;
-  };
-
-  template<typename...A>
-  struct StateEventListener {
-    uint32_t id;
-    IStateOwner *owner;
-    std::function<void(A...)> listener;
-    std::function<void(StateEventListener<A...>)> unsubWithParams;
-    std::function<void()> unsub;
-    StateEvent<A...> *event;
-  };
-
-  class IStateEvent {
+  class StateEvent : public IStateEvent {
     protected:
+      uint32_t stateEventId = 0;
+
       /**
        * Received notification from a state owner to let this state event know
        * that it wishes to unsubscribe all the event listeners that it may have
@@ -36,17 +19,6 @@ namespace Dawn {
        * 
        * @param owner State owner that is being disposed.
        */
-      virtual void _stateOwnerDestroyed(IStateOwner *owner) = 0;
-
-      friend class StateOwner;
-  };
-
-  template<typename...A>
-  class StateEvent : public IStateEvent {
-    protected:
-      uint32_t stateEventId = 0;
-
-      /** Refer to IStateEvent::_stateOwnerDestroyed */
       void _stateOwnerDestroyed(IStateOwner *owner) override {
         auto it = this->_eventListeners.begin();
         while(it != this->_eventListeners.end()) {

src/dawn/state/StateInterfaces.hpp

@@ -0,0 +1,53 @@
+// Copyright (c) 2023 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#pragma once
+#include "assert/assert.hpp"
+#include "event/Event.hpp"
+
+namespace Dawn {
+  class IStateEvent;
+
+  template<typename...A>
+  class StateEvent;
+
+  template<typename ...A>
+  class StateOwnerEventLegacy;
+
+  class IStateOwnerEventLegacy {
+    public:
+      virtual void removeListener() = 0;
+      virtual void teardown() = 0;
+  };
+
+  class IStateOwner {
+    public:
+      virtual void _stateEventDisposed(IStateEvent *evt) = 0;
+      virtual void _stateLegacyEventDisposed(IStateOwnerEventLegacy *evt) = 0;
+  };
+
+  template<typename...A>
+  struct StateEventListener {
+    uint32_t id;
+    IStateOwner *owner;
+    std::function<void(A...)> listener;
+    std::function<void(StateEventListener<A...>)> unsubWithParams;
+    std::function<void()> unsub;
+    StateEvent<A...> *event;
+  };
+  
+  class IStateProperty {
+    public:
+      std::vector<std::function<void()>> _effectListners;
+      std::vector<std::function<std::function<void()>()>> _effectListnersWithTeardown;
+      std::vector<std::function<void()>> _effectTeardowns;
+  };
+
+  class IStateEvent {
+    protected:
+      virtual void _stateOwnerDestroyed(IStateOwner *owner) = 0;
+      friend class StateOwner;
+  };
+}

src/dawn/state/StateProperty.hpp

@@ -4,16 +4,9 @@
 // https://opensource.org/licenses/MIT
 
 #pragma once
-#include "assert/assert.hpp"
+#include "StateInterfaces.hpp"
 
 namespace Dawn {
-  class IStateProperty {
-    public:
-      std::vector<std::function<void()>> _effectListners;
-      std::vector<std::function<std::function<void()>()>> _effectListnersWithTeardown;
-      std::vector<std::function<void()>> _effectTeardowns;
-  };
-
   template<class V>
   class StateProperty : public IStateProperty {
     private: