Initial commit

include/wfr/common/eventsystem/EventSystem.h

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+
+#pragma once
+
+#include <mutex>
+#include <thread>
+#include <condition_variable>
+#include <queue>
+#include <unordered_set>
+#include <atomic>
+#include <memory>
+#include <wfr/config.h>
+
+
+namespace wfr {
+
+// forward declarations
+class WorkflowRuntime;
+
+namespace eventsystem {
+
+// forward declarations
+class EventListener;
+class Event;
+class OStreamLogger;
+class SQLiteLogger;
+
+
+class EventSystem {
+friend class wfr::WorkflowRuntime;
+
+// Singleton instances
+private:
+	static EventSystem singleton;
+	#ifdef WFR_ENABLE_STDLOGGER
+		static std::unique_ptr<OStreamLogger> oStreamLogger;
+	#endif
+	#ifdef WFR_ENABLE_PERFDATABASE
+		static std::unique_ptr<SQLiteLogger> sqliteLogger;
+	#endif
+
+// Non-public parameters
+private:
+	std::unordered_set<EventListener*> eventListeners;
+	std::queue<std::shared_ptr<Event>> eventQueue;
+	std::unique_ptr<std::thread> eventThread;
+	std::mutex eventThreadMutex;
+	std::condition_variable eventThreadCondVar;
+	bool stopThread = false;
+	std::atomic_bool threadStarted;
+	bool isFinished = false;
+
+// Non-public static functions
+private:
+	static void eventThreadFunc(EventSystem* eventSystem) noexcept;
+
+	static void init(int argc, char** argv);
+	static void finish() noexcept;
+
+// Non-public functions
+private:
+	EventSystem() noexcept;
+
+	void finishInstance() noexcept;
+
+// Public functions
+public:
+	~EventSystem() noexcept;
+	static EventSystem& getInstance() noexcept { return singleton; }
+
+	/**
+	 * Adds an event to the event queue.
+	 *
+	 * It is discouraged to use this function directly.
+	 * Use the static fireEvent function found in each Event class instead (e.g. GeneralLoggingEvent::fireEvent(....)).
+	 **/
+	void fireEvent(std::shared_ptr<Event> event, bool noLocking = false) noexcept;
+
+	bool addListener(EventListener& listener) noexcept;
+	bool removeListener(EventListener& listener) noexcept;
+};
+
+
+} /* namespace eventsystem */
+} /* namespace wfr */
+