EventProcessor.h

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/*
 * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef __EVENTPROCESSOR_H
#define __EVENTPROCESSOR_H
 
#include "Define.h"
#include "Duration.h"
#include "Random.h"
#include <map>
#include <type_traits>
 
class EventProcessor;
 
// Note. All times are in milliseconds here.
 
class TC_COMMON_API BasicEvent
{
 friend class EventProcessor;
 
 enum class AbortState : uint8
 {
 STATE_RUNNING,
 STATE_ABORT_SCHEDULED,
 STATE_ABORTED
 };
 
 public:
 BasicEvent()
 : m_abortState(AbortState::STATE_RUNNING), m_addTime(0), m_execTime(0) { }
 
 virtual ~BasicEvent() { } // override destructor to perform some actions on event removal
 
 // this method executes when the event is triggered
 // return false if event does not want to be deleted
 // e_time is execution time, p_time is update interval
 virtual bool Execute(uint64 /*e_time*/, uint32 /*p_time*/) { return true; }
 
 virtual bool IsDeletable() const { return true; } // this event can be safely deleted
 
 virtual void Abort(uint64 /*e_time*/) { } // this method executes when the event is aborted
 
 // Aborts the event at the next update tick
 void ScheduleAbort();
 
 private:
 void SetAborted();
 bool IsRunning() const { return (m_abortState == AbortState::STATE_RUNNING); }
 bool IsAbortScheduled() const { return (m_abortState == AbortState::STATE_ABORT_SCHEDULED); }
 bool IsAborted() const { return (m_abortState == AbortState::STATE_ABORTED); }
 
 AbortState m_abortState; // set by externals when the event is aborted, aborted events don't execute
 
 // these can be used for time offset control
 uint64 m_addTime; // time when the event was added to queue, filled by event handler
 uint64 m_execTime; // planned time of next execution, filled by event handler
};
 
template<typename T>
class LambdaBasicEvent : public BasicEvent
{
public:
 LambdaBasicEvent(T&& callback) : BasicEvent(), _callback(std::move(callback)) { }
 
 bool Execute(uint64, uint32) override
 {
 _callback();
 return true;
 }
 
private:
 
 T _callback;
};
 
template<typename T>
using is_lambda_event = std::enable_if_t<!std::is_base_of_v<BasicEvent, std::remove_pointer_t<std::remove_cvref_t<T>>>>;
 
class TC_COMMON_API EventProcessor
{
 public:
 EventProcessor() : m_time(0) { }
 ~EventProcessor();
 
 void Update(uint32 p_time);
 void KillAllEvents(bool force);
 
 void AddEvent(BasicEvent* event, Milliseconds e_time, bool set_addtime = true);
 template<typename T>
 is_lambda_event<T> AddEvent(T&& event, Milliseconds e_time, bool set_addtime = true) { AddEvent(new LambdaBasicEvent<T>(std::move(event)), e_time, set_addtime); }
 void AddEventAtOffset(BasicEvent* event, Milliseconds offset) { AddEvent(event, CalculateTime(offset)); }
 void AddEventAtOffset(BasicEvent* event, Milliseconds offset, Milliseconds offset2) { AddEvent(event, CalculateTime(randtime(offset, offset2))); }
 template<typename T>
 is_lambda_event<T> AddEventAtOffset(T&& event, Milliseconds offset) { AddEventAtOffset(new LambdaBasicEvent<T>(std::move(event)), offset); }
 template<typename T>
 is_lambda_event<T> AddEventAtOffset(T&& event, Milliseconds offset, Milliseconds offset2) { AddEventAtOffset(new LambdaBasicEvent<T>(std::move(event)), offset, offset2); }
 void ModifyEventTime(BasicEvent* event, Milliseconds newTime);
 Milliseconds CalculateTime(Milliseconds t_offset) const { return Milliseconds(m_time) + t_offset; }
 std::multimap<uint64, BasicEvent*> const& GetEvents() const { return m_events; }
 
 protected:
 uint64 m_time;
 std::multimap<uint64, BasicEvent*> m_events;
};
 
#endif