Added object metadata for Plugins, use WeakMap on perms

src/pocketmine/metadata/MetadataStore.php

@@ -0,0 +1,130 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+/**
+ * Saves extra data on runtime for different items
+ */
+namespace pocketmine\metadata;
+
+use pocketmine\plugin\Plugin;
+
+abstract class MetadataStore{
+	/** @var \WeakMap[] */
+	private $metadataMap = [];
+
+	/**
+	 * Adds a metadata value to an object.
+	 *
+	 * @param mixed        $subject
+	 * @param string        $metadataKey
+	 * @param MetadataValue $newMetadataValue
+	 */
+	public function setMetadata($subject, $metadataKey, MetadataValue $newMetadataValue){
+		$owningPlugin = $newMetadataValue->getOwningPlugin();
+		if($owningPlugin === null){
+			trigger_error("Plugin cannot be null", E_USER_WARNING);
+			return;
+		}
+
+		$key = $this->disambiguate($subject, $newMetadataValue);
+		if(!isset($this->metadataMap[$key])){
+			$entry = new \WeakMap();
+			$this->metadataMap[$key] = $entry;
+		}else{
+			$entry = $this->metadataMap[$key];
+		}
+		$entry[$owningPlugin] = $newMetadataValue;
+	}
+
+	/**
+	 * Returns all metadata values attached to an object. If multiple
+	 * have attached metadata, each will value will be included.
+	 *
+	 * @param mixed $subject
+	 * @param string $metadataKey
+	 *
+	 * @return MetadataValue[]
+	 */
+	public function getMetadata($subject, $metadataKey){
+		$key = $this->disambiguate($subject, $metadataKey);
+		if(isset($this->metadataMap[$key])){
+			return $this->metadataMap[$key];
+		}else{
+			return [];
+		}
+	}
+
+	/**
+	 * Tests to see if a metadata attribute has been set on an object.
+	 *
+	 * @param mixed $subject
+	 * @param string $metadataKey
+	 *
+	 * @return bool
+	 */
+	public function hasMetadata($subject, $metadataKey){
+		return isset($this->metadataMap[$this->disambiguate($subject, $metadataKey)]);
+	}
+
+	/**
+	 * Removes a metadata item owned by a plugin from a subject.
+	 *
+	 * @param mixed $subject
+	 * @param string $metadataKey
+	 * @param Plugin $owningPlugin
+	 */
+	public function removeMetadata($subject, $metadataKey, Plugin $owningPlugin){
+		$key = $this->disambiguate($subject, $metadataKey);
+		if(isset($this->metadataMap[$key])){
+			unset($this->metadataMap[$key][$owningPlugin]);
+			if($this->metadataMap[$key]->count() === 0){
+				unset($this->metadataMap[$key]);
+			}
+		}
+	}
+
+	/**
+	 * Invalidates all metadata in the metadata store that originates from the
+	 * given plugin. Doing this will force each invalidated metadata item to
+	 * be recalculated the next time it is accessed.
+	 *
+	 * @param Plugin $owningPlugin
+	 */
+	public function invalidateAll(Plugin $owningPlugin){
+		/** @var $values MetadataValue[] */
+		foreach($this->metadataMap as $values){
+			if(isset($values[$owningPlugin])){
+				$values[$owningPlugin]->invalidate();
+			}
+		}
+	}
+
+	/**
+	 * Creates a unique name for the object receiving metadata by combining
+	 * unique data from the subject with a metadataKey.
+	 *
+	 * @param mixed $subject
+	 * @param string $metadataKey
+	 *
+	 * @return string
+	 */
+	public abstract function disambiguate($subject, $metadataKey);
+}