diff options
Diffstat (limited to 'src/crepe/api/EventManager.h')
| -rw-r--r-- | src/crepe/api/EventManager.h | 199 |
1 files changed, 119 insertions, 80 deletions
diff --git a/src/crepe/api/EventManager.h b/src/crepe/api/EventManager.h index 38d2e64..348a04d 100644 --- a/src/crepe/api/EventManager.h +++ b/src/crepe/api/EventManager.h @@ -1,8 +1,6 @@ #pragma once -#include <functional> #include <memory> -#include <type_traits> #include <typeindex> #include <unordered_map> #include <vector> @@ -10,113 +8,154 @@ #include "Event.h" #include "EventHandler.h" - namespace crepe { + +//! Event listener unique ID +typedef size_t subscription_t; + +/** + * \brief Event channel + * + * Events can be sent to a specific channel, which prevents listeners on other channels from + * being called. The default channel is EventManager::CHANNEL_ALL, which calls all listeners. + */ +typedef size_t event_channel_t; + /** * \class EventManager - * \brief The EventManager class is responsible for managing the subscription, triggering, - * and queueing of events. It handles events and dispatches them to appropriate subscribers. + * \brief Manages event subscriptions, triggers, and queues, enabling decoupled event handling. + * + * The `EventManager` acts as a centralized event system. It allows for registering callbacks + * for specific event types, triggering events synchronously, queueing events for later + * processing, and managing subscriptions via unique identifiers. */ class EventManager { public: - /** - * \brief Deleted copy constructor to prevent copying of the EventManager instance. - */ - EventManager(const EventManager &) = delete; - - /** - * \brief Deleted copy assignment operator to prevent assignment of the EventManager instance. - */ - const EventManager & operator=(const EventManager &) = delete; + static constexpr const event_channel_t CHANNEL_ALL = -1; /** - * \brief Get the singleton instance of the EventManager. - * - * This method returns the unique instance of the EventManager, creating it on the first call. - * - * \return Reference to the EventManager instance. - */ + * \brief Get the singleton instance of the EventManager. + * + * This method returns the unique instance of the EventManager, creating it if it + * doesn't already exist. Ensures only one instance is active in the program. + * + * \return Reference to the singleton instance of the EventManager. + */ static EventManager & get_instance(); /** - * \brief Subscribe to an event. - * - * This method allows the registration of a callback for a specific event type and channel. - * - * \tparam EventType The type of the event to subscribe to. - * \param callback The callback function to invoke when the event is triggered. - * \param channel The channel number to subscribe to (default is 0). - */ + * \brief Subscribe to a specific event type. + * + * Registers a callback for a given event type and optional channel. Each callback + * is assigned a unique subscription ID that can be used for later unsubscription. + * + * \tparam EventType The type of the event to subscribe to. + * \param callback The callback function to be invoked when the event is triggered. + * \param channel The channel number to subscribe to (default is CHANNEL_ALL, which listens to all channels). + * \return A unique subscription ID associated with the registered callback. + */ template <typename EventType> - void subscribe(EventHandler<EventType> && callback, int channel = 0); + subscription_t subscribe(const EventHandler<EventType> & callback, + event_channel_t channel = CHANNEL_ALL); /** - * \brief Unsubscribe from an event. - * - * This method removes a previously registered callback from an event. - * - * \tparam EventType The type of the event to unsubscribe from. - * \param callback The callback function to remove from the subscription list. - * \param channel The event ID to unsubscribe from. - */ - template <typename EventType> - void unsubscribe(const EventHandler<EventType> &, int channel); + * \brief Unsubscribe a previously registered callback. + * + * Removes a callback from the subscription list based on its unique subscription ID. + * + * \param event_id The unique subscription ID of the callback to remove. + */ + void unsubscribe(subscription_t event_id); /** - * \brief Trigger an event. - * - * This method invokes the appropriate callback(s) for the specified event. - * - * \tparam EventType The type of the event to trigger. - * \param event The event data to pass to the callback. - * \param channel The channel from which to trigger the event (default is 0). - */ + * \brief Trigger an event immediately. + * + * Synchronously invokes all registered callbacks for the given event type on the specified channel. + * + * \tparam EventType The type of the event to trigger. + * \param event The event instance to pass to the callbacks. + * \param channel The channel to trigger the event on (default is CHANNEL_ALL, which triggers on all channels). + */ template <typename EventType> - void trigger_event(const EventType & event, int channel); + void trigger_event(const EventType & event, event_channel_t channel = CHANNEL_ALL); /** - * \brief Queue an event for later processing. - * - * This method adds an event to the event queue, which will be processed in the - * dispatch_events function. - * - * \tparam EventType The type of the event to queue. - * \param event The event to queue. - * \param channel The channel number for the event (default is 0). - */ + * \brief Queue an event for later processing. + * + * Adds an event to the event queue to be processed during the next call to `dispatch_events`. + * + * \tparam EventType The type of the event to queue. + * \param event The event instance to queue. + * \param channel The channel to associate with the event (default is CHANNEL_ALL). + */ template <typename EventType> - void queue_event(EventType && event, int channel); + void queue_event(const EventType & event, event_channel_t channel = CHANNEL_ALL); /** - * \brief Dispatch all queued events. - * - * This method processes all events in the event queue and triggers the corresponding - * callbacks for each event. - */ + * \brief Process all queued events. + * + * Iterates through the event queue and triggers callbacks for each queued event. + * Events are removed from the queue once processed. + */ void dispatch_events(); + /** + * \brief Clear all subscriptions. + * + * Removes all registered event handlers and clears the subscription list. + */ + void clear(); + private: /** - * \brief Default constructor for the EventManager. - * - * This constructor is private to enforce the singleton pattern. - */ + * \brief Default constructor for the EventManager. + * + * Constructor is private to enforce the singleton pattern. + */ EventManager() = default; - //! The queue of events to be processed. - std::vector<std::tuple<std::unique_ptr<Event>, int, std::type_index>> - events_queue; - //! Registered event handlers. - std::unordered_map<std::type_index, - std::vector<std::unique_ptr<IEventHandlerWrapper>>> - subscribers; - //! Event handlers indexed by event ID. - std::unordered_map< - std::type_index, - std::unordered_map<int, - std::vector<std::unique_ptr<IEventHandlerWrapper>>>> - subscribers_by_event_id; + /** + * \struct QueueEntry + * \brief Represents an entry in the event queue. + */ + struct QueueEntry { + std::unique_ptr<Event> event; ///< The event instance. + event_channel_t channel = CHANNEL_ALL; ///< The channel associated with the event. + std::type_index type; ///< The type of the event. + }; + + /** + * \brief Internal event handler + * + * This function processes a single event, and is used to process events both during + * EventManager::dispatch_events and inside EventManager::trigger_event + * + * \param type \c typeid of concrete Event class + * \param channel Event channel + * \param data Event data + */ + void handle_event(std::type_index type, event_channel_t channel, const Event & data); + + /** + * \struct CallbackEntry + * \brief Represents a registered event handler callback. + */ + struct CallbackEntry { + std::unique_ptr<IEventHandlerWrapper> callback; ///< The callback function wrapper. + event_channel_t channel = CHANNEL_ALL; ///< The channel this callback listens to. + subscription_t id = -1; ///< Unique subscription ID. + }; + + //! The queue of events to be processed during dispatch. + std::vector<QueueEntry> events_queue; + + //! A map of event type to registered callbacks. + std::unordered_map<std::type_index, std::vector<CallbackEntry>> subscribers; + + //! Counter to generate unique subscription IDs. + subscription_t subscription_counter = 0; }; } // namespace crepe + #include "EventManager.hpp" |