Added Event Broker

include/Engine/Core/Event.h

@@ -0,0 +1,10 @@
+#ifndef Event_h__
+#define Event_h__
+
+struct Event
+{
+protected:
+	Event() { }
+};
+
+#endif

include/Engine/Core/EventBroker.h

@@ -0,0 +1,136 @@
+#ifndef EventBroker_h__
+#define EventBroker_h__
+
+#include <typeinfo>
+#include <functional>
+#include <map>
+#include <unordered_map>
+#include <list>
+#include <tuple>
+
+#include "Event.h"
+
+#define EVENT_SUBSCRIBE_MEMBER(relay, handler) \
+	relay = decltype(relay)(std::bind(handler, this, std::placeholders::_1)); \
+	EventBroker->Subscribe(relay);
+
+class EventBroker;
+
+class BaseEventRelay
+{
+friend class EventBroker;
+
+protected:
+	BaseEventRelay(std::string contextTypeName, std::string eventTypeName)
+		: m_ContextTypeName(contextTypeName)
+		, m_EventTypeName(eventTypeName)
+		, m_Broker(nullptr) 
+	{ }
+	~BaseEventRelay();
+
+public:
+	virtual bool Receive(const std::shared_ptr<Event> event) = 0;
+
+protected:
+	std::string m_ContextTypeName;
+	std::string m_EventTypeName;
+	EventBroker* m_Broker;
+};
+
+template <typename ContextType, typename EventType>
+class EventRelay : public BaseEventRelay
+{
+public:
+	typedef std::function<bool(const EventType&)> CallbackType;
+
+	EventRelay()
+		: m_Callback(nullptr)
+		, BaseEventRelay(typeid(ContextType).name(), typeid(EventType).name()) 
+	{ }
+	EventRelay(CallbackType callback) 
+		: m_Callback(callback)
+		, BaseEventRelay(typeid(ContextType).name(), typeid(EventType).name()) 
+	{ }
+
+protected:
+	bool Receive(const std::shared_ptr<Event> event) override;
+
+private:
+	CallbackType m_Callback;
+};
+
+template <typename ContextType, typename EventType>
+bool EventRelay<ContextType, EventType>::Receive(const std::shared_ptr<Event> event)
+{
+	if (m_Callback != nullptr) {
+		return m_Callback(*static_cast<const EventType*>(event.get()));
+	} else {
+		return false;
+	}
+}
+
+class EventBroker
+{
+template <typename ContextType, typename EventType> friend class EventRelay;
+
+public:
+	EventBroker()
+	{
+		m_EventQueueRead = std::make_shared<EventQueue_t>();
+		m_EventQueueWrite = std::make_shared<EventQueue_t>();
+	}
+
+	void Subscribe(BaseEventRelay &relay);
+	template <typename EventType>
+	void Publish(const EventType &event);
+	/*
+		Process all events in a given context.
+		Returns: Number of events processed
+	*/
+	template <typename ContextType>
+	int Process();
+	int Process(std::string contextTypeName);
+	void Swap();
+	void Clear();
+	void Unsubscribe(BaseEventRelay &relay);
+
+private:
+	bool m_IsProcessing = false;
+
+	typedef std::string ContextTypeName_t; // typeid(ContextType).name()
+	typedef std::string EventTypeName_t; // typeid(EventType).name()
+
+	typedef std::unordered_multimap<EventTypeName_t, BaseEventRelay*> EventRelays_t;
+	typedef std::unordered_map<ContextTypeName_t, EventRelays_t> ContextRelays_t;
+	ContextRelays_t m_ContextRelays;
+	std::vector<BaseEventRelay*> m_RelaysToSubscribe;
+	std::vector<BaseEventRelay*> m_RelaysToUnsubscribe;
+
+	typedef std::list<std::pair<EventTypeName_t, std::shared_ptr<Event>>> EventQueue_t;
+	std::shared_ptr<EventQueue_t> m_EventQueueRead;
+	std::shared_ptr<EventQueue_t> m_EventQueueWrite;
+
+	void subscribeImmediate(BaseEventRelay& relay);
+	void unsubscribeImmediate(BaseEventRelay& relay);
+};
+
+template <typename EventType>
+void EventBroker::Publish(const EventType &event)
+{
+	/*auto itpair = m_Subscribers.equal_range(typeid(EventType).name());
+	for (auto it = itpair.first; it != itpair.second; ++it)
+	{
+		it->second->Receive(event);
+	}*/
+
+	m_EventQueueWrite->push_back(std::make_pair(typeid(EventType).name(), std::shared_ptr<EventType>(new EventType(event))));
+}
+
+template <typename ContextType>
+int EventBroker::Process()
+{
+	const std::string contextTypeName = typeid(ContextType).name();
+	return Process(contextTypeName);
+}
+
+#endif