Fibers

fibers.php

<?php

declare(strict_types=1);

class Loop
{

    private static ?Loop $loop = null;

    private array $queue = [];

    private bool $running = false;

    private static function get(): self
    {
        if (self::$loop === null) {
            self::$loop = new static;
        }

        return self::$loop;
    }

    public static function futureTick(callable $callable): void
    {
        Loop::get()->queue[] = new Fiber($callable);
    }

    public static function run(): void
    {
        $loop = Loop::get();

        $loop->running = true;

        while ($loop->running) {
            if ($loop->queue !== []) {
                $fiber = array_shift($loop->queue);

                if (!$fiber->isStarted()) {
                    $fiber->start();
                    $loop->queue[] = $fiber;
                } elseif ($fiber->isSuspended()) {
                    $fiber->resume();
                    $loop->queue[] = $fiber;
                }
            }

            if ($loop->queue === []) {
                $loop->running = false;
            }
        }
    }

}

register_shutdown_function(Loop::run(...));

Loop::futureTick(fn() => print date('c') . ' - tick' . PHP_EOL);

Loop::futureTick(function () {
    print date('c') . ' - fiber 1' . PHP_EOL;
    Fiber::suspend();
    print date('c') . ' - fiber 1' . PHP_EOL;
});

Loop::futureTick(fn() => print date('c') . ' - tock' . PHP_EOL);

Loop::futureTick(static function () {
    print date('c') . ' - going to sleep' . PHP_EOL;
    Fiber::suspend();
    print date('c') . ' - zug zug' . PHP_EOL;
});