From 0a1f0d96db6482ddbdfce00e923211803060ca4f Mon Sep 17 00:00:00 2001
From: sippeangelo <holmerg.simon@gmail.com>
Date: Tue, 24 Nov 2015 10:37:21 +0100
Subject: [PATCH] Added Event Broker

---
 include/Engine/Core/Event.h        |  10 +++
 include/Engine/Core/EventBroker.h  | 136 +++++++++++++++++++++++++++++
 include/Engine/PrecompiledHeader.h |  26 ++++++
 src/Engine/Core/EventBroker.cpp    | 104 ++++++++++++++++++++++
 src/Engine/PrecompiledHeader.cpp   |   1 +
 5 files changed, 277 insertions(+)
 create mode 100644 include/Engine/Core/Event.h
 create mode 100644 include/Engine/Core/EventBroker.h
 create mode 100644 include/Engine/PrecompiledHeader.h
 create mode 100644 src/Engine/Core/EventBroker.cpp
 create mode 100644 src/Engine/PrecompiledHeader.cpp

diff --git a/include/Engine/Core/Event.h b/include/Engine/Core/Event.h
new file mode 100644
index 00000000..65adb3a9
--- /dev/null
+++ b/include/Engine/Core/Event.h
@@ -0,0 +1,10 @@
+#ifndef Event_h__
+#define Event_h__
+
+struct Event
+{
+protected:
+	Event() { }
+};
+
+#endif
diff --git a/include/Engine/Core/EventBroker.h b/include/Engine/Core/EventBroker.h
new file mode 100644
index 00000000..3144ed85
--- /dev/null
+++ b/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
diff --git a/include/Engine/PrecompiledHeader.h b/include/Engine/PrecompiledHeader.h
new file mode 100644
index 00000000..0ac917d2
--- /dev/null
+++ b/include/Engine/PrecompiledHeader.h
@@ -0,0 +1,26 @@
+#include <memory>
+#include <string>
+#include <vector>
+#include <map>
+#include <unordered_map>
+
+// OpenGL
+#include <GL/glew.h>
+#define GLFW_INCLUDE_GLU
+#define NOMINMAX
+#include <GLFW/glfw3.h>
+#include <glext.h>
+#include "Core/Util/GLError.h"
+
+// GLM
+#define GLM_FORCE_RADIANS
+#include <glm/glm.hpp>
+#include <glm/common.hpp>
+#include <glm/gtc/constants.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/gtx/rotate_vector.hpp>
+#include <glm/gtc/quaternion.hpp>
+#include <glm/gtx/quaternion.hpp>
+#include <glm/gtc/type_ptr.hpp>
+
+#include "Core/Util/Logging.h"
diff --git a/src/Engine/Core/EventBroker.cpp b/src/Engine/Core/EventBroker.cpp
new file mode 100644
index 00000000..a1c253dd
--- /dev/null
+++ b/src/Engine/Core/EventBroker.cpp
@@ -0,0 +1,104 @@
+#include "PrecompiledHeader.h"
+#include "Core/EventBroker.h"
+
+BaseEventRelay::~BaseEventRelay()
+{
+	if (m_Broker != nullptr) {
+		m_Broker->Unsubscribe(*this);
+	}
+}
+
+void EventBroker::Unsubscribe(BaseEventRelay &relay) // ?
+{
+	if (m_IsProcessing) {
+		m_RelaysToUnsubscribe.push_back(&relay);
+	} else {
+		unsubscribeImmediate(relay);
+	}
+}
+
+void EventBroker::Subscribe(BaseEventRelay &relay)
+{
+	if (m_IsProcessing) {
+		m_RelaysToSubscribe.push_back(&relay);
+	} else {
+		subscribeImmediate(relay);
+	}
+}
+
+int EventBroker::Process(std::string contextTypeName)
+{
+	m_IsProcessing = true;
+
+	auto it = m_ContextRelays.find(contextTypeName);
+	if (it == m_ContextRelays.end()) {
+		return 0;
+	}
+
+	EventRelays_t &relays = it->second;
+
+	int eventsProcessed = 0;
+	for (auto &pair : *m_EventQueueRead) {
+		std::string &eventTypeName = pair.first;
+		std::shared_ptr<Event> event = pair.second;
+
+		auto itpair = relays.equal_range(eventTypeName);
+		for (auto it2 = itpair.first; it2 != itpair.second; it2++)
+		{
+			std::string name = it2->first;
+			BaseEventRelay* relay = it2->second;
+			relay->Receive(event);
+			eventsProcessed++;
+		}
+	}
+
+	m_IsProcessing = false;
+
+	// Process pending subscriptions
+	for (auto& r : m_RelaysToSubscribe) {
+		subscribeImmediate(*r);
+	}
+	m_RelaysToSubscribe.clear();
+
+	// Process pending unsubscriptions
+	for (auto& r : m_RelaysToUnsubscribe) {
+		unsubscribeImmediate(*r);
+	}
+	m_RelaysToUnsubscribe.clear();
+
+	return eventsProcessed;
+}
+
+void EventBroker::Swap()
+{
+	std::swap(m_EventQueueRead, m_EventQueueWrite);
+}
+
+void EventBroker::Clear()
+{
+	m_EventQueueWrite->clear();
+}
+
+void EventBroker::subscribeImmediate(BaseEventRelay& relay)
+{
+	relay.m_Broker = this;
+	m_ContextRelays[relay.m_ContextTypeName].insert(std::make_pair(relay.m_EventTypeName, &relay));
+}
+
+void EventBroker::unsubscribeImmediate(BaseEventRelay& relay)
+{
+	auto contextIt = m_ContextRelays.find(relay.m_ContextTypeName);
+	if (contextIt == m_ContextRelays.end()) {
+		return;
+	}
+
+	auto eventRelays = contextIt->second;
+	auto itpair = eventRelays.equal_range(relay.m_EventTypeName);
+	for (auto it = itpair.first; it != itpair.second; ++it) {
+		if (it->second == &relay) {
+			relay.m_Broker = nullptr;
+			eventRelays.erase(it);
+			break;
+		}
+	}
+}
diff --git a/src/Engine/PrecompiledHeader.cpp b/src/Engine/PrecompiledHeader.cpp
new file mode 100644
index 00000000..6d8a5001
--- /dev/null
+++ b/src/Engine/PrecompiledHeader.cpp
@@ -0,0 +1 @@
+#include "PrecompiledHeader.h"