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    <h3>Editing: ProfilerListener.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/*
 * 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\HttpKernel\EventListener;

use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\RequestMatcherInterface;
use Symfony\Component\HttpFoundation\RequestStack;
use Symfony\Component\HttpFoundation\Session\Session;
use Symfony\Component\HttpKernel\Event\ExceptionEvent;
use Symfony\Component\HttpKernel\Event\ResponseEvent;
use Symfony\Component\HttpKernel\Event\TerminateEvent;
use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\HttpKernel\Profiler\Profile;
use Symfony\Component\HttpKernel\Profiler\Profiler;

/**
 * ProfilerListener collects data for the current request by listening to the kernel events.
 *
 * @author Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * @final
 */
class ProfilerListener implements EventSubscriberInterface
{
    protected $profiler;
    protected $matcher;
    protected $onlyException;
    protected $onlyMainRequests;
    protected $exception;
    /** @var \SplObjectStorage&lt;Request, Profile&gt; */
    protected $profiles;
    protected $requestStack;
    protected $collectParameter;
    /** @var \SplObjectStorage&lt;Request, Request|null&gt; */
    protected $parents;

    /**
     * @param bool $onlyException    True if the profiler only collects data when an exception occurs, false otherwise
     * @param bool $onlyMainRequests True if the profiler only collects data when the request is the main request, false otherwise
     */
    public function __construct(Profiler $profiler, RequestStack $requestStack, ?RequestMatcherInterface $matcher = null, bool $onlyException = false, bool $onlyMainRequests = false, ?string $collectParameter = null)
    {
        $this-&gt;profiler = $profiler;
        $this-&gt;matcher = $matcher;
        $this-&gt;onlyException = $onlyException;
        $this-&gt;onlyMainRequests = $onlyMainRequests;
        $this-&gt;profiles = new \SplObjectStorage();
        $this-&gt;parents = new \SplObjectStorage();
        $this-&gt;requestStack = $requestStack;
        $this-&gt;collectParameter = $collectParameter;
    }

    /**
     * Handles the onKernelException event.
     */
    public function onKernelException(ExceptionEvent $event)
    {
        if ($this-&gt;onlyMainRequests &amp;&amp; !$event-&gt;isMainRequest()) {
            return;
        }

        $this-&gt;exception = $event-&gt;getThrowable();
    }

    /**
     * Handles the onKernelResponse event.
     */
    public function onKernelResponse(ResponseEvent $event)
    {
        if ($this-&gt;onlyMainRequests &amp;&amp; !$event-&gt;isMainRequest()) {
            return;
        }

        if ($this-&gt;onlyException &amp;&amp; null === $this-&gt;exception) {
            return;
        }

        $request = $event-&gt;getRequest();
        if (null !== $this-&gt;collectParameter &amp;&amp; null !== $collectParameterValue = $request-&gt;get($this-&gt;collectParameter)) {
            true === $collectParameterValue || filter_var($collectParameterValue, \FILTER_VALIDATE_BOOLEAN) ? $this-&gt;profiler-&gt;enable() : $this-&gt;profiler-&gt;disable();
        }

        $exception = $this-&gt;exception;
        $this-&gt;exception = null;

        if (null !== $this-&gt;matcher &amp;&amp; !$this-&gt;matcher-&gt;matches($request)) {
            return;
        }

        $session = !$request-&gt;attributes-&gt;getBoolean('_stateless') &amp;&amp; $request-&gt;hasPreviousSession() &amp;&amp; $request-&gt;hasSession() ? $request-&gt;getSession() : null;

        if ($session instanceof Session) {
            $usageIndexValue = $usageIndexReference = &amp;$session-&gt;getUsageIndex();
            $usageIndexReference = \PHP_INT_MIN;
        }

        try {
            if (!$profile = $this-&gt;profiler-&gt;collect($request, $event-&gt;getResponse(), $exception)) {
                return;
            }
        } finally {
            if ($session instanceof Session) {
                $usageIndexReference = $usageIndexValue;
            }
        }

        $this-&gt;profiles[$request] = $profile;

        $this-&gt;parents[$request] = $this-&gt;requestStack-&gt;getParentRequest();
    }

    public function onKernelTerminate(TerminateEvent $event)
    {
        // attach children to parents
        foreach ($this-&gt;profiles as $request) {
            if (null !== $parentRequest = $this-&gt;parents[$request]) {
                if (isset($this-&gt;profiles[$parentRequest])) {
                    $this-&gt;profiles[$parentRequest]-&gt;addChild($this-&gt;profiles[$request]);
                }
            }
        }

        // save profiles
        foreach ($this-&gt;profiles as $request) {
            $this-&gt;profiler-&gt;saveProfile($this-&gt;profiles[$request]);
        }

        $this-&gt;profiles = new \SplObjectStorage();
        $this-&gt;parents = new \SplObjectStorage();
    }

    public static function getSubscribedEvents(): array
    {
        return [
            KernelEvents::RESPONSE =&gt; ['onKernelResponse', -100],
            KernelEvents::EXCEPTION =&gt; ['onKernelException', 0],
            KernelEvents::TERMINATE =&gt; ['onKernelTerminate', -1024],
        ];
    }
}
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