TraceableEventDispatcher.php

<?php


/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Symfony\Component\EventDispatcher\Debug;

use Psr\EventDispatcher\StoppableEventInterface;
use Psr\Log\LoggerInterface;
use Symfony\Component\EventDispatcher\EventDispatcher;
use Symfony\Component\EventDispatcher\EventDispatcherInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\RequestStack;
use Symfony\Component\Stopwatch\Stopwatch;
use Symfony\Contracts\Service\ResetInterface;

/**
 * Collects some data about event listeners.
 *
 * This event dispatcher delegates the dispatching to another one.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 */
class TraceableEventDispatcher implements EventDispatcherInterface, ResetInterface {
    
    /**
     * @var \SplObjectStorage<WrappedListener, array{string, string}>|null
     */
    private ?\SplObjectStorage $callStack = null;
    private array $wrappedListeners = [];
    private array $orphanedEvents = [];
    private string $currentRequestHash = '';
    public function __construct(EventDispatcherInterface $dispatcher, Stopwatch $stopwatch, ?LoggerInterface $logger = null, ?RequestStack $requestStack = null) {
    }
    public function addListener(string $eventName, callable|array $listener, int $priority = 0) : void {
        $this->dispatcher
            ->addListener($eventName, $listener, $priority);
    }
    public function addSubscriber(EventSubscriberInterface $subscriber) : void {
        $this->dispatcher
            ->addSubscriber($subscriber);
    }
    public function removeListener(string $eventName, callable|array $listener) : void {
        if (isset($this->wrappedListeners[$eventName])) {
            foreach ($this->wrappedListeners[$eventName] as $index => $wrappedListener) {
                if ($wrappedListener->getWrappedListener() === $listener || $listener instanceof \Closure && $wrappedListener->getWrappedListener() == $listener) {
                    $listener = $wrappedListener;
                    unset($this->wrappedListeners[$eventName][$index]);
                    break;
                }
            }
        }
        $this->dispatcher
            ->removeListener($eventName, $listener);
    }
    public function removeSubscriber(EventSubscriberInterface $subscriber) : void {
        $this->dispatcher
            ->removeSubscriber($subscriber);
    }
    public function getListeners(?string $eventName = null) : array {
        return $this->dispatcher
            ->getListeners($eventName);
    }
    public function getListenerPriority(string $eventName, callable|array $listener) : ?int {
        // we might have wrapped listeners for the event (if called while dispatching)
        // in that case get the priority by wrapper
        if (isset($this->wrappedListeners[$eventName])) {
            foreach ($this->wrappedListeners[$eventName] as $wrappedListener) {
                if ($wrappedListener->getWrappedListener() === $listener || $listener instanceof \Closure && $wrappedListener->getWrappedListener() == $listener) {
                    return $this->dispatcher
                        ->getListenerPriority($eventName, $wrappedListener);
                }
            }
        }
        return $this->dispatcher
            ->getListenerPriority($eventName, $listener);
    }
    public function hasListeners(?string $eventName = null) : bool {
        return $this->dispatcher
            ->hasListeners($eventName);
    }
    public function dispatch(object $event, ?string $eventName = null) : object {
        $eventName ??= $event::class;
        $this->callStack ??= new \SplObjectStorage();
        $currentRequestHash = $this->currentRequestHash = $this->requestStack && ($request = $this->requestStack
            ->getCurrentRequest()) ? spl_object_hash($request) : '';
        if (null !== $this->logger && $event instanceof StoppableEventInterface && $event->isPropagationStopped()) {
            $this->logger
                ->debug(\sprintf('The "%s" event is already stopped. No listeners have been called.', $eventName));
        }
        $this->preProcess($eventName);
        try {
            $this->beforeDispatch($eventName, $event);
            try {
                $e = $this->stopwatch
                    ->start($eventName, 'section');
                try {
                    $this->dispatcher
                        ->dispatch($event, $eventName);
                } finally {
                    if ($e->isStarted()) {
                        $e->stop();
                    }
                }
            } finally {
                $this->afterDispatch($eventName, $event);
            }
        } finally {
            $this->currentRequestHash = $currentRequestHash;
            $this->postProcess($eventName);
        }
        return $event;
    }
    public function getCalledListeners(?Request $request = null) : array {
        if (null === $this->callStack) {
            return [];
        }
        $hash = $request ? spl_object_hash($request) : null;
        $called = [];
        foreach ($this->callStack as $listener) {
            [
                $eventName,
                $requestHash,
            ] = $this->callStack
                ->getInfo();
            if (null === $hash || $hash === $requestHash) {
                $called[] = $listener->getInfo($eventName);
            }
        }
        return $called;
    }
    public function getNotCalledListeners(?Request $request = null) : array {
        try {
            $allListeners = $this->dispatcher instanceof EventDispatcher ? $this->getListenersWithPriority() : $this->getListenersWithoutPriority();
        } catch (\Exception $e) {
            $this->logger?->info('An exception was thrown while getting the uncalled listeners.', [
                'exception' => $e,
            ]);
            // unable to retrieve the uncalled listeners
            return [];
        }
        $hash = $request ? spl_object_hash($request) : null;
        $calledListeners = [];
        if (null !== $this->callStack) {
            foreach ($this->callStack as $calledListener) {
                [
                    ,
                    $requestHash,
                ] = $this->callStack
                    ->getInfo();
                if (null === $hash || $hash === $requestHash) {
                    $calledListeners[] = $calledListener->getWrappedListener();
                }
            }
        }
        $notCalled = [];
        foreach ($allListeners as $eventName => $listeners) {
            foreach ($listeners as [
                $listener,
                $priority,
            ]) {
                if (!\in_array($listener, $calledListeners, true)) {
                    if (!$listener instanceof WrappedListener) {
                        $listener = new WrappedListener($listener, null, $this->stopwatch, $this, $priority);
                    }
                    $notCalled[] = $listener->getInfo($eventName);
                }
            }
        }
        uasort($notCalled, $this->sortNotCalledListeners(...));
        return $notCalled;
    }
    public function getOrphanedEvents(?Request $request = null) : array {
        if ($request) {
            return $this->orphanedEvents[spl_object_hash($request)] ?? [];
        }
        if (!$this->orphanedEvents) {
            return [];
        }
        return array_merge(...array_values($this->orphanedEvents));
    }
    public function reset() : void {
        $this->callStack = null;
        $this->orphanedEvents = [];
        $this->currentRequestHash = '';
    }
    
    /**
     * Proxies all method calls to the original event dispatcher.
     *
     * @param string $method    The method name
     * @param array  $arguments The method arguments
     */
    public function __call(string $method, array $arguments) : mixed {
        return $this->dispatcher
            ->{$method}(...$arguments);
    }
    
    /**
     * Called before dispatching the event.
     */
    protected function beforeDispatch(string $eventName, object $event) : void {
    }
    
    /**
     * Called after dispatching the event.
     */
    protected function afterDispatch(string $eventName, object $event) : void {
    }
    private function preProcess(string $eventName) : void {
        if (!$this->dispatcher
            ->hasListeners($eventName)) {
            $this->orphanedEvents[$this->currentRequestHash][] = $eventName;
            return;
        }
        foreach ($this->dispatcher
            ->getListeners($eventName) as $listener) {
            $priority = $this->getListenerPriority($eventName, $listener);
            $wrappedListener = new WrappedListener($listener instanceof WrappedListener ? $listener->getWrappedListener() : $listener, null, $this->stopwatch, $this);
            $this->wrappedListeners[$eventName][] = $wrappedListener;
            $this->dispatcher
                ->removeListener($eventName, $listener);
            $this->dispatcher
                ->addListener($eventName, $wrappedListener, $priority);
            $this->callStack
                ->attach($wrappedListener, [
                $eventName,
                $this->currentRequestHash,
            ]);
        }
    }
    private function postProcess(string $eventName) : void {
        unset($this->wrappedListeners[$eventName]);
        $skipped = false;
        foreach ($this->dispatcher
            ->getListeners($eventName) as $listener) {
            if (!$listener instanceof WrappedListener) {
                // #12845: a new listener was added during dispatch.
                continue;
            }
            // Unwrap listener
            $priority = $this->getListenerPriority($eventName, $listener);
            $this->dispatcher
                ->removeListener($eventName, $listener);
            $this->dispatcher
                ->addListener($eventName, $listener->getWrappedListener(), $priority);
            if (null !== $this->logger) {
                $context = [
                    'event' => $eventName,
                    'listener' => $listener->getPretty(),
                ];
            }
            if ($listener->wasCalled()) {
                $this->logger?->debug('Notified event "{event}" to listener "{listener}".', $context);
            }
            else {
                $this->callStack
                    ->detach($listener);
            }
            if (null !== $this->logger && $skipped) {
                $this->logger
                    ->debug('Listener "{listener}" was not called for event "{event}".', $context);
            }
            if ($listener->stoppedPropagation()) {
                $this->logger?->debug('Listener "{listener}" stopped propagation of the event "{event}".', $context);
                $skipped = true;
            }
        }
    }
    private function sortNotCalledListeners(array $a, array $b) : int {
        if (0 !== ($cmp = strcmp($a['event'], $b['event']))) {
            return $cmp;
        }
        if (\is_int($a['priority']) && !\is_int($b['priority'])) {
            return 1;
        }
        if (!\is_int($a['priority']) && \is_int($b['priority'])) {
            return -1;
        }
        if ($a['priority'] === $b['priority']) {
            return 0;
        }
        if ($a['priority'] > $b['priority']) {
            return -1;
        }
        return 1;
    }
    private function getListenersWithPriority() : array {
        $result = [];
        $allListeners = new \ReflectionProperty(EventDispatcher::class, 'listeners');
        foreach ($allListeners->getValue($this->dispatcher) as $eventName => $listenersByPriority) {
            foreach ($listenersByPriority as $priority => $listeners) {
                foreach ($listeners as $listener) {
                    $result[$eventName][] = [
                        $listener,
                        $priority,
                    ];
                }
            }
        }
        return $result;
    }
    private function getListenersWithoutPriority() : array {
        $result = [];
        foreach ($this->getListeners() as $eventName => $listeners) {
            foreach ($listeners as $listener) {
                $result[$eventName][] = [
                    $listener,
                    null,
                ];
            }
        }
        return $result;
    }

}