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    <h3>Editing: SignalRegistry.php</h3>
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/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Console\SignalRegistry;

final class SignalRegistry
{
    private $signalHandlers = [];

    public function __construct()
    {
        if (\function_exists('pcntl_async_signals')) {
            pcntl_async_signals(true);
        }
    }

    public function register(int $signal, callable $signalHandler): void
    {
        if (!isset($this-&gt;signalHandlers[$signal])) {
            $previousCallback = pcntl_signal_get_handler($signal);

            if (\is_callable($previousCallback)) {
                $this-&gt;signalHandlers[$signal][] = $previousCallback;
            }
        }

        $this-&gt;signalHandlers[$signal][] = $signalHandler;

        pcntl_signal($signal, [$this, 'handle']);
    }

    public static function isSupported(): bool
    {
        if (!\function_exists('pcntl_signal')) {
            return false;
        }

        if (\in_array('pcntl_signal', explode(',', \ini_get('disable_functions')))) {
            return false;
        }

        return true;
    }

    /**
     * @internal
     */
    public function handle(int $signal): void
    {
        $count = \count($this-&gt;signalHandlers[$signal]);

        foreach ($this-&gt;signalHandlers[$signal] as $i =&gt; $signalHandler) {
            $hasNext = $i !== $count - 1;
            $signalHandler($signal, $hasNext);
        }
    }
}
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