Move event calling functionality to Event->call() method

This is dependent on the changes made in b1e0f82cbf. This now makes it possible to call events without fetching a Server reference, allowing to eliminate a vast array of Server dependencies.

src/pocketmine/event/Event.php

@@ -27,6 +27,9 @@ declare(strict_types=1);
 namespace pocketmine\event;
 
 abstract class Event{
+	private const MAX_EVENT_CALL_DEPTH = 50;
+	/** @var int */
+	private static $eventCallDepth = 1;
 
 	/** @var string|null */
 	protected $eventName = null;
@@ -67,4 +70,38 @@ abstract class Event{
 		/** @var Event $this */
 		$this->isCancelled = $value;
 	}
+
+	/**
+	 * Calls event handlers registered for this event.
+	 *
+	 * @throws \RuntimeException if event call recursion reaches the max depth limit
+	 *
+	 * @throws \ReflectionException
+	 */
+	public function call() : void{
+		if(self::$eventCallDepth >= self::MAX_EVENT_CALL_DEPTH){
+			//this exception will be caught by the parent event call if all else fails
+			throw new \RuntimeException("Recursive event call detected (reached max depth of " . self::MAX_EVENT_CALL_DEPTH . " calls)");
+		}
+
+		$handlerList = HandlerList::getHandlerListFor(get_class($this));
+		assert($handlerList !== null, "Called event should have a valid HandlerList");
+
+		++self::$eventCallDepth;
+		foreach(EventPriority::ALL as $priority){
+			$currentList = $handlerList;
+			while($currentList !== null){
+				foreach($currentList->getListenersByPriority($priority) as $registration){
+					if(!$registration->getPlugin()->isEnabled()){
+						continue;
+					}
+
+					$registration->callEvent($this);
+				}
+
+				$currentList = $currentList->getParent();
+			}
+		}
+		--self::$eventCallDepth;
+	}
 }