RmlUi/Source/Core/EventDispatcher.h

/*
 * This source file is part of RmlUi, the HTML/CSS Interface Middleware
 *
 * For the latest information, see http://github.com/mikke89/RmlUi
 *
 * Copyright (c) 2008-2010 CodePoint Ltd, Shift Technology Ltd
 * Copyright (c) 2019-2023 The RmlUi Team, and contributors
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and 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 notice and 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.
 *
 */

#ifndef RMLUI_CORE_EVENTDISPATCHER_H
#define RMLUI_CORE_EVENTDISPATCHER_H

#include "../../Include/RmlUi/Core/Event.h"
#include "../../Include/RmlUi/Core/Types.h"

namespace Rml {

class Element;
class EventListener;
struct CollectedListener;

struct EventListenerEntry {
	EventListenerEntry(const EventId id, EventListener* listener, const bool in_capture_phase) :
		id(id), in_capture_phase(in_capture_phase), listener(listener)
	{}

	EventId id;
	bool in_capture_phase;
	EventListener* listener;
};

/**
    The Event Dispatcher manages a list of event listeners and triggers the events via EventHandlers
    whenever requested.

    @author Lloyd Weehuizen
*/

class EventDispatcher {
public:
	/// Constructor
	/// @param element Element this dispatcher acts on
	EventDispatcher(Element* element);

	/// Destructor
	~EventDispatcher();

	/// Attaches a new listener to the specified event name.
	/// @param[in] type Type of the event to attach to.
	/// @param[in] event_listener The event listener to be notified when the event fires.
	/// @param[in] in_capture_phase Should the listener be notified in the capture phase.
	void AttachEvent(EventId id, EventListener* event_listener, bool in_capture_phase);

	/// Detaches a listener from the specified event name
	/// @param[in] type Type of the event to attach to
	/// @param[in] event_listener The event listener to be notified when the event fires
	/// @param[in] in_capture_phase Should the listener be notified in the capture phase
	void DetachEvent(EventId id, EventListener* listener, bool in_capture_phase);

	/// Detaches all events from this dispatcher and all child dispatchers.
	void DetachAllEvents();

	/// Dispatches the specified event.
	/// @param[in] target_element The element to target
	/// @param[in] id The id of the event
	/// @param[in] type The type of the event
	/// @param[in] parameters The event parameters
	/// @param[in] interruptible Can the event propagation be stopped
	/// @param[in] bubbles True if the event should execute the bubble phase
	/// @param[in] default_action_phase The phases to execute default actions in
	/// @return True if the event was not consumed (ie, was prevented from propagating by an element), false if it was.
	static bool DispatchEvent(Element* target_element, EventId id, const String& type, const Dictionary& parameters, bool interruptible, bool bubbles,
		DefaultActionPhase default_action_phase);

	/// Returns event types with number of listeners for debugging.
	/// @return Summary of attached listeners.
	String ToString() const;

private:
	Element* element;

	// Listeners are sorted first by (id, phase) and then by the order in which the listener was inserted.
	// All listeners added are unique.
	typedef Vector<EventListenerEntry> Listeners;
	Listeners listeners;

	// Collect all the listeners from this dispatcher that are allowed to execute given the input arguments.
	void CollectListeners(int dom_distance_from_target, EventId event_id, EventPhase phases_to_execute, Vector<CollectedListener>& collect_listeners);
};

} // namespace Rml
#endif