ConsoleReader.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\console;
 
use pocketmine\utils\Utils;
use function fclose;
use function fgets;
use function fopen;
use function is_resource;
use function stream_select;
use function trim;
use function usleep;
 
final class ConsoleReader{
    private $stdin;
 
    public function __construct(){
        $this->initStdin();
    }
 
    private function initStdin() : void{
        if(is_resource($this->stdin)){
            fclose($this->stdin);
        }
 
        $this->stdin = Utils::assumeNotFalse(fopen("php://stdin", "r"), "Opening stdin should never fail");
    }
 
    public function readLine() : ?string{
        if(!is_resource($this->stdin)){
            $this->initStdin();
        }
 
        $r = [$this->stdin];
        $w = $e = null;
        if(($count = stream_select($r, $w, $e, 0, 200000)) === 0){ //nothing changed in 200000 microseconds
            return null;
        }elseif($count === false){ //stream error
            return null;
        }
 
        if(($raw = fgets($this->stdin)) === false){ //broken pipe or EOF
            usleep(200000); //prevent CPU waste if it's end of pipe
            return null; //loop back round
        }
 
        $line = trim($raw);
 
        return $line !== "" ? $line : null;
    }
 
    public function __destruct(){
        fclose($this->stdin);
    }
}