Event.h

/*
MIT License

Copyright(c) 2019 Tim Lucassen

Permission is hereby granted, free of charge, to any person obtaining a copy
of this softwareand associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and /or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions :

The above copyright noticeand this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
#pragma once

#include <vector>
#include <mutex>
#include <assert.h>
/*
* Event Class Instantiated with template arguments that will be used during Dispatch.
*/
template<typename... Args>
class Event
{

private:

	//BaseClass interface for storing multiple different types of Subscribers in one container
	template<typename... Args>
	class BaseEventSubscription
	{
	public:

		BaseEventSubscription() {}

		virtual ~BaseEventSubscription() {}

		virtual void DispatchToSubscriber(Args... args) = 0;

	};

	//Templated Subscription class
	template<typename Type, typename... Args>
	class EventSubscription : public BaseEventSubscription<Args...>
	{

	public:

		EventSubscription(Type* Object, void(Type::* FunctionPtr)(Args...)) { m_Subscriber = Object;  m_FunctionPtr = FunctionPtr; }
		virtual ~EventSubscription() {}

		virtual void DispatchToSubscriber(Args... args) override
		{
			if (m_Subscriber != nullptr && m_FunctionPtr != nullptr)
			{
				(*m_Subscriber.*m_FunctionPtr)(args...);
			}
		}

	private:

		Type* m_Subscriber;
		void(Type::* m_FunctionPtr)(Args...);

	};

public:

	Event(){}

	virtual ~Event()
	{
		for (size_t i = 0; i < m_EventSubsribers.size(); i++)
		{
			delete m_EventSubsribers[i];
		}
		m_EventSubsribers.clear();
	}

	Event(const Event& Rhs) 
	{
		std::lock_guard<std::mutex> Lock(m_Mutex);
		for (size_t i = 0; i < m_EventSubsribers.size(); i++)
		{
			BaseEventSubscription* CopiedSubscriber = new BaseEventSubscription();
			&CopiedSubscriber = &m_EventSubsribers[i];
			Rhs.m_EventSubsribers.push_back(CopiedSubscriber);
		}
	}

	/*
	* @Description: Registers a new Object and Member Function to the Event. Event will call registered function on Dispatch()
	* @Param[in] Object: Subscriber object
	* @Param[in] FunctionPtr: Function pointer to a member function of the Subscriber object
	* @Template Type: Type of the Subscribing object
	*/
	template<typename SubscriberType>
	void Register(SubscriberType* Object, void(SubscriberType::*FunctionPtr)(Args...)) 
	{
		std::lock_guard<std::mutex> Lock(m_Mutex);
		EventSubscription<SubscriberType, Args...>* Subscriber = new EventSubscription<SubscriberType, Args...>(Object, FunctionPtr);
		m_EventSubsribers.push_back(Subscriber);
	}

	/*
	* @Description: Clears all registered subscribers from the Events
	*/
	void UnregisterAll() 
	{
		std::lock_guard<std::mutex> Lock(m_Mutex);

		for (size_t i = 0; i < m_EventSubsribers.size(); i++)
		{
			delete m_EventSubsribers[i];
		}
		m_EventSubsribers.clear();
	}

	/*
	* @Description: Calls all Subscribed member functions
	*/
	void Dispatch(Args... args) 
	{
		std::lock_guard<std::mutex> Lock(m_Mutex);

		for (BaseEventSubscription<Args...>* Subscriber : m_EventSubsribers)
		{
			if (Subscriber)
			{
				Subscriber->DispatchToSubscriber(args...);
			}
		}
	}

private:

	std::vector<BaseEventSubscription<Args...>*> m_EventSubsribers;

	std::mutex m_Mutex;

};