From 2232753b994dfb65ae46f07f827b89858faea4db Mon Sep 17 00:00:00 2001
From: Maxence Lange <maxence@artificial-owl.com>
Date: Wed, 14 Feb 2024 14:02:20 -0100
Subject: [PATCH] add hasListeners()

Signed-off-by: Maxence Lange <maxence@artificial-owl.com>
---
 .../EventDispatcher/EventDispatcher.php       | 26 +++++++------------
 lib/private/Log.php                           | 21 +++++++--------
 .../EventDispatcher/IEventDispatcher.php      |  9 +++++++
 3 files changed, 28 insertions(+), 28 deletions(-)

diff --git a/lib/private/EventDispatcher/EventDispatcher.php b/lib/private/EventDispatcher/EventDispatcher.php
index 14c13d516c0..39bf2a6afa9 100644
--- a/lib/private/EventDispatcher/EventDispatcher.php
+++ b/lib/private/EventDispatcher/EventDispatcher.php
@@ -33,29 +33,17 @@ use OCP\Broadcast\Events\IBroadcastEvent;
 use OCP\EventDispatcher\ABroadcastedEvent;
 use OCP\EventDispatcher\Event;
 use OCP\EventDispatcher\IEventDispatcher;
-use OCP\IContainer;
 use OCP\IServerContainer;
 use Psr\Log\LoggerInterface;
 use Symfony\Component\EventDispatcher\EventDispatcher as SymfonyDispatcher;
 use function get_class;
 
 class EventDispatcher implements IEventDispatcher {
-	/** @var SymfonyDispatcher */
-	private $dispatcher;
-
-	/** @var IContainer */
-	private $container;
-
-	/** @var LoggerInterface */
-	private $logger;
-
-	public function __construct(SymfonyDispatcher $dispatcher,
-		IServerContainer $container,
-		LoggerInterface $logger) {
-		$this->dispatcher = $dispatcher;
-		$this->container = $container;
-		$this->logger = $logger;
-
+	public function __construct(
+		private SymfonyDispatcher $dispatcher,
+		private IServerContainer $container,
+		private LoggerInterface $logger,
+	) {
 		// inject the event dispatcher into the logger
 		// this is done here because there is a cyclic dependency between the event dispatcher and logger
 		if ($this->logger instanceof Log || $this->logger instanceof Log\PsrLoggerAdapter) {
@@ -86,6 +74,10 @@ class EventDispatcher implements IEventDispatcher {
 		$this->addListener($eventName, $listener, $priority);
 	}
 
+	public function hasListeners(string $eventName): bool {
+		return $this->dispatcher->hasListeners($eventName);
+	}
+
 	/**
 	 * @deprecated
 	 */
diff --git a/lib/private/Log.php b/lib/private/Log.php
index 83ff1003294..2ad214ddec5 100644
--- a/lib/private/Log.php
+++ b/lib/private/Log.php
@@ -207,8 +207,10 @@ class Log implements ILogger, IDataLogger {
 	 */
 	public function log(int $level, string $message, array $context = []) {
 		$minLevel = $this->getLogLevel($context);
-		if ($level < $minLevel && (($this->crashReporters?->hasReporters() ?? false) === false)) {
-			return; // we already know that log will be fully ignored
+		if ($level < $minLevel
+			&& (($this->crashReporters?->hasReporters() ?? false) === false)
+			&& (($this->eventDispatcher?->hasListeners(BeforeMessageLoggedEvent::class) ?? false) === false)) {
+			return; // no crash reporter, no listeners, we can stop for lower log level
 		}
 
 		array_walk($context, [$this->normalizer, 'format']);
@@ -216,9 +218,7 @@ class Log implements ILogger, IDataLogger {
 		$app = $context['app'] ?? 'no app in context';
 		$entry = $this->interpolateMessage($context, $message);
 
-		if ($this->eventDispatcher) {
-			$this->eventDispatcher->dispatchTyped(new BeforeMessageLoggedEvent($app, $level, $entry));
-		}
+		$this->eventDispatcher?->dispatchTyped(new BeforeMessageLoggedEvent($app, $level, $entry));
 
 		$hasBacktrace = isset($entry['exception']);
 		$logBacktrace = $this->config->getValue('log.backtrace', false);
@@ -326,8 +326,10 @@ class Log implements ILogger, IDataLogger {
 		$level = $context['level'] ?? ILogger::ERROR;
 
 		$minLevel = $this->getLogLevel($context);
-		if ($level < $minLevel && (($this->crashReporters?->hasReporters() ?? false) === false)) {
-			return; // we already know that log will be fully ignored
+		if ($level < $minLevel
+			&& (($this->crashReporters?->hasReporters() ?? false) === false)
+			&& (($this->eventDispatcher?->hasListeners(BeforeMessageLoggedEvent::class) ?? false) === false)) {
+			return; // no crash reporter, no listeners, we can stop for lower log level
 		}
 
 		// if an error is raised before the autoloader is properly setup, we can't serialize exceptions
@@ -343,12 +345,9 @@ class Log implements ILogger, IDataLogger {
 		$data = array_merge($serializer->serializeException($exception), $data);
 		$data = $this->interpolateMessage($data, isset($context['message']) && $context['message'] !== '' ? $context['message'] : ('Exception thrown: ' . get_class($exception)), 'CustomMessage');
 
-
 		array_walk($context, [$this->normalizer, 'format']);
 
-		if ($this->eventDispatcher) {
-			$this->eventDispatcher->dispatchTyped(new BeforeMessageLoggedEvent($app, $level, $data));
-		}
+		$this->eventDispatcher?->dispatchTyped(new BeforeMessageLoggedEvent($app, $level, $data));
 
 		try {
 			if ($level >= $minLevel) {
diff --git a/lib/public/EventDispatcher/IEventDispatcher.php b/lib/public/EventDispatcher/IEventDispatcher.php
index 0a96fa799d4..a84e0fe2f3b 100644
--- a/lib/public/EventDispatcher/IEventDispatcher.php
+++ b/lib/public/EventDispatcher/IEventDispatcher.php
@@ -69,6 +69,15 @@ interface IEventDispatcher {
 	 */
 	public function addServiceListener(string $eventName, string $className, int $priority = 0): void;
 
+	/**
+	 * @template T of \OCP\EventDispatcher\Event
+	 * @param string $eventName preferably the fully-qualified class name of the Event sub class
+	 *
+	 * @return bool TRUE if event has registered listeners
+	 * @since 29.0.0
+	 */
+	public function hasListeners(string $eventName): bool;
+
 	/**
 	 * @template T of \OCP\EventDispatcher\Event
 	 * @param string $eventName