Added Event Broker

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;
+		}
+	}
+}