Tracking de l'application VApp (IHM du jeu)

VApp/node_modules/mqtt/src/lib/topic-alias-send.ts

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+/**
+ * Module dependencies
+ */
+import { LRUCache } from 'lru-cache'
+import { NumberAllocator } from 'number-allocator'
+
+/**
+ * Topic Alias sending manager
+ * This holds both topic to alias and alias to topic map
+ * @param {Number} [max] - topic alias maximum entries
+ */
+export default class TopicAliasSend {
+	private aliasToTopic: LRUCache<number, string>
+
+	private topicToAlias: Record<string, number>
+
+	private max: number
+
+	private numberAllocator: NumberAllocator
+
+	public length: number
+
+	constructor(max: number) {
+		if (max > 0) {
+			this.aliasToTopic = new LRUCache<number, string>({ max })
+			this.topicToAlias = {}
+			this.numberAllocator = new NumberAllocator(1, max)
+			this.max = max
+			this.length = 0
+		}
+	}
+
+	/**
+	 * Insert or update topic - alias entry.
+	 * @param {String} [topic] - topic
+	 * @param {Number} [alias] - topic alias
+	 * @returns {Boolean} - if success return true otherwise false
+	 */
+	put(topic: string, alias: number): boolean {
+		if (alias === 0 || alias > this.max) {
+			return false
+		}
+		const entry = this.aliasToTopic.get(alias)
+		if (entry) {
+			delete this.topicToAlias[entry]
+		}
+		this.aliasToTopic.set(alias, topic)
+		this.topicToAlias[topic] = alias
+		this.numberAllocator.use(alias)
+		this.length = this.aliasToTopic.size
+		return true
+	}
+
+	/**
+	 * Get topic by alias
+	 * @param {Number} [alias] - topic alias
+	 * @returns {String} - if mapped topic exists return topic, otherwise return undefined
+	 */
+	getTopicByAlias(alias: number): string {
+		return this.aliasToTopic.get(alias)
+	}
+
+	/**
+	 * Get topic by alias
+	 * @param {String} [topic] - topic
+	 * @returns {Number} - if mapped topic exists return topic alias, otherwise return undefined
+	 */
+	getAliasByTopic(topic: string): number | undefined {
+		const alias = this.topicToAlias[topic]
+		if (typeof alias !== 'undefined') {
+			this.aliasToTopic.get(alias) // LRU update
+		}
+		return alias
+	}
+
+	/**
+	 * Clear all entries
+	 */
+	clear() {
+		this.aliasToTopic.clear()
+		this.topicToAlias = {}
+		this.numberAllocator.clear()
+		this.length = 0
+	}
+
+	/**
+	 * Get Least Recently Used (LRU) topic alias
+	 * @returns {Number} - if vacant alias exists then return it, otherwise then return LRU alias
+	 */
+	getLruAlias(): number {
+		const alias = this.numberAllocator.firstVacant()
+		if (alias) return alias
+		// get last alias (key) from LRU cache
+		return [...this.aliasToTopic.keys()][this.aliasToTopic.size - 1]
+	}
+}