Merge pull request #5707 from pmmp/hot-events-optimisation

Avoid unnecessary event-related work in hot paths when the events have no registered handlers

src/event/Event.php

@@ -27,6 +27,7 @@ declare(strict_types=1);
 namespace pocketmine\event;
 
 use pocketmine\timings\Timings;
+use function count;
 use function get_class;
 
 abstract class Event{
@@ -54,11 +55,11 @@ abstract class Event{
 		$timings = Timings::getEventTimings($this);
 		$timings->startTiming();
 
-		$handlerList = HandlerListManager::global()->getListFor(get_class($this));
+		$handlers = HandlerListManager::global()->getHandlersFor(static::class);
 
 		++self::$eventCallDepth;
 		try{
-			foreach($handlerList->getListenerList() as $registration){
+			foreach($handlers as $registration){
 				$registration->callEvent($this);
 			}
 		}finally{
@@ -66,4 +67,14 @@ abstract class Event{
 			$timings->stopTiming();
 		}
 	}
+
+	/**
+	 * Returns whether the current class context has any registered global handlers.
+	 * This can be used in hot code paths to avoid unnecessary event object creation.
+	 *
+	 * Usage: SomeEventClass::hasHandlers()
+	 */
+	public static function hasHandlers() : bool{
+		return count(HandlerListManager::global()->getHandlersFor(static::class)) > 0;
+	}
 }

src/event/HandlerList.php

@@ -33,8 +33,6 @@ class HandlerList{
 	/** @var RegisteredListener[][] */
 	private array $handlerSlots = [];
 
-	private RegisteredListenerCache $handlerCache;
-
 	/** @var RegisteredListenerCache[] */
 	private array $affectedHandlerCaches = [];
 
@@ -44,9 +42,9 @@ class HandlerList{
 	 */
 	public function __construct(
 		private string $class,
-		private ?HandlerList $parentList
+		private ?HandlerList $parentList,
+		private RegisteredListenerCache $handlerCache = new RegisteredListenerCache()
 	){
-		$this->handlerCache = new RegisteredListenerCache();
 		for($list = $this; $list !== null; $list = $list->parentList){
 			$list->affectedHandlerCaches[spl_object_id($this->handlerCache)] = $this->handlerCache;
 		}

src/event/HandlerListManager.php

@@ -36,6 +36,11 @@ class HandlerListManager{
 
 	/** @var HandlerList[] classname => HandlerList */
 	private array $allLists = [];
+	/**
+	 * @var RegisteredListenerCache[] event class name => cache
+	 * @phpstan-var array<class-string<Event>, RegisteredListenerCache>
+	 */
+	private array $handlerCaches = [];
 
 	/**
 	 * Unregisters all the listeners
@@ -98,7 +103,25 @@ class HandlerListManager{
 		}
 
 		$parent = self::resolveNearestHandleableParent($class);
-		return $this->allLists[$event] = new HandlerList($event, $parent !== null ? $this->getListFor($parent->getName()) : null);
+		$cache = new RegisteredListenerCache();
+		$this->handlerCaches[$event] = $cache;
+		return $this->allLists[$event] = new HandlerList(
+			$event,
+			parentList: $parent !== null ? $this->getListFor($parent->getName()) : null,
+			handlerCache: $cache
+		);
+	}
+
+	/**
+	 * @phpstan-template TEvent of Event
+	 * @phpstan-param class-string<TEvent> $event
+	 *
+	 * @return RegisteredListener[]
+	 */
+	public function getHandlersFor(string $event) : array{
+		$cache = $this->handlerCaches[$event] ?? null;
+		//getListFor() will populate the cache for the next call
+		return $cache?->list ?? $this->getListFor($event)->getListenerList();
 	}
 
 	/**

src/network/mcpe/NetworkSession.php

@@ -406,10 +406,12 @@ class NetworkSession{
 		$timings->startTiming();
 
 		try{
-			$ev = new DataPacketDecodeEvent($this, $packet->pid(), $buffer);
-			$ev->call();
-			if($ev->isCancelled()){
-				return;
+			if(DataPacketDecodeEvent::hasHandlers()){
+				$ev = new DataPacketDecodeEvent($this, $packet->pid(), $buffer);
+				$ev->call();
+				if($ev->isCancelled()){
+					return;
+				}
 			}
 
 			$decodeTimings = Timings::getDecodeDataPacketTimings($packet);
@@ -429,19 +431,22 @@ class NetworkSession{
 				$decodeTimings->stopTiming();
 			}
 
-			$ev = new DataPacketReceiveEvent($this, $packet);
-			$ev->call();
-			if(!$ev->isCancelled()){
-				$handlerTimings = Timings::getHandleDataPacketTimings($packet);
-				$handlerTimings->startTiming();
-				try{
-					if($this->handler === null || !$packet->handle($this->handler)){
-						$this->logger->debug("Unhandled " . $packet->getName() . ": " . base64_encode($stream->getBuffer()));
-					}
-				}finally{
-					$handlerTimings->stopTiming();
+			if(DataPacketReceiveEvent::hasHandlers()){
+				$ev = new DataPacketReceiveEvent($this, $packet);
+				$ev->call();
+				if($ev->isCancelled()){
+					return;
 				}
 			}
+			$handlerTimings = Timings::getHandleDataPacketTimings($packet);
+			$handlerTimings->startTiming();
+			try{
+				if($this->handler === null || !$packet->handle($this->handler)){
+					$this->logger->debug("Unhandled " . $packet->getName() . ": " . base64_encode($stream->getBuffer()));
+				}
+			}finally{
+				$handlerTimings->stopTiming();
+			}
 		}finally{
 			$timings->stopTiming();
 		}
@@ -459,12 +464,16 @@ class NetworkSession{
 		$timings = Timings::getSendDataPacketTimings($packet);
 		$timings->startTiming();
 		try{
-			$ev = new DataPacketSendEvent([$this], [$packet]);
-			$ev->call();
-			if($ev->isCancelled()){
-				return false;
+			if(DataPacketSendEvent::hasHandlers()){
+				$ev = new DataPacketSendEvent([$this], [$packet]);
+				$ev->call();
+				if($ev->isCancelled()){
+					return false;
+				}
+				$packets = $ev->getPackets();
+			}else{
+				$packets = [$packet];
 			}
-			$packets = $ev->getPackets();
 
 			foreach($packets as $evPacket){
 				$this->addToSendBuffer(self::encodePacketTimed(PacketSerializer::encoder($this->packetSerializerContext), $evPacket));

src/network/mcpe/StandardPacketBroadcaster.php

@@ -44,12 +44,14 @@ final class StandardPacketBroadcaster implements PacketBroadcaster{
 	public function broadcastPackets(array $recipients, array $packets) : void{
 		//TODO: this shouldn't really be called here, since the broadcaster might be replaced by an alternative
 		//implementation that doesn't fire events
-		$ev = new DataPacketSendEvent($recipients, $packets);
-		$ev->call();
-		if($ev->isCancelled()){
-			return;
+		if(DataPacketSendEvent::hasHandlers()){
+			$ev = new DataPacketSendEvent($recipients, $packets);
+			$ev->call();
+			if($ev->isCancelled()){
+				return;
+			}
+			$packets = $ev->getPackets();
 		}
-		$packets = $ev->getPackets();
 
 		$compressors = [];