TaskScheduler.php

<?php
 
/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
 */
 
declare(strict_types=1);
 
namespace pocketmine\scheduler;
 
use pocketmine\utils\ObjectSet;
use pocketmine\utils\ReversePriorityQueue;
 
class TaskScheduler{
    private bool $enabled = true;
 
    protected ReversePriorityQueue $queue;
 
    protected ObjectSet $tasks;
 
    protected int $currentTick = 0;
 
    public function __construct(
        private ?string $owner = null
    ){
        $this->queue = new ReversePriorityQueue();
        $this->tasks = new ObjectSet();
    }
 
    public function scheduleTask(Task $task) : TaskHandler{
        return $this->addTask($task, -1, -1);
    }
 
    public function scheduleDelayedTask(Task $task, int $delay) : TaskHandler{
        return $this->addTask($task, $delay, -1);
    }
 
    public function scheduleRepeatingTask(Task $task, int $period) : TaskHandler{
        return $this->addTask($task, -1, $period);
    }
 
    public function scheduleDelayedRepeatingTask(Task $task, int $delay, int $period) : TaskHandler{
        return $this->addTask($task, $delay, $period);
    }
 
    public function cancelAllTasks() : void{
        foreach($this->tasks as $id => $task){
            $task->cancel();
        }
        $this->tasks->clear();
        while(!$this->queue->isEmpty()){
            $this->queue->extract();
        }
    }
 
    public function isQueued(TaskHandler $task) : bool{
        return $this->tasks->contains($task);
    }
 
    private function addTask(Task $task, int $delay, int $period) : TaskHandler{
        if(!$this->enabled){
            throw new \LogicException("Tried to schedule task to disabled scheduler");
        }
 
        if($delay <= 0){
            $delay = -1;
        }
 
        if($period <= -1){
            $period = -1;
        }elseif($period < 1){
            $period = 1;
        }
 
        return $this->handle(new TaskHandler($task, $delay, $period, $this->owner));
    }
 
    private function handle(TaskHandler $handler) : TaskHandler{
        if($handler->isDelayed()){
            $nextRun = $this->currentTick + $handler->getDelay();
        }else{
            $nextRun = $this->currentTick;
        }
 
        $handler->setNextRun($nextRun);
        $this->tasks->add($handler);
        $this->queue->insert($handler, $nextRun);
 
        return $handler;
    }
 
    public function shutdown() : void{
        $this->enabled = false;
        $this->cancelAllTasks();
    }
 
    public function setEnabled(bool $enabled) : void{
        $this->enabled = $enabled;
    }
 
    public function mainThreadHeartbeat(int $currentTick) : void{
        if(!$this->enabled){
            throw new \LogicException("Cannot run heartbeat on a disabled scheduler");
        }
        $this->currentTick = $currentTick;
        while($this->isReady($this->currentTick)){
            $task = $this->queue->extract();
            if($task->isCancelled()){
                $this->tasks->remove($task);
                continue;
            }
            $task->run();
            if(!$task->isCancelled() && $task->isRepeating()){
                $task->setNextRun($this->currentTick + $task->getPeriod());
                $this->queue->insert($task, $this->currentTick + $task->getPeriod());
            }else{
                $task->remove();
                $this->tasks->remove($task);
            }
        }
    }
 
    private function isReady(int $currentTick) : bool{
        return !$this->queue->isEmpty() && $this->queue->current()->getNextRun() <= $currentTick;
    }
}