src/utils/AsyncLock.ts

   1 // Partial Copyright Jerome Benoit. 2021-2023. All Rights Reserved.
   2
   3 import Queue from 'mnemonist/queue.js';
   4
   5 export enum AsyncLockType {
   6   configuration = 'configuration',
   7   performance = 'performance',
   8 }
   9
  10 type ResolveType = (value: void | PromiseLike<void>) => void;
  11
  12 export class AsyncLock {
  13   private static readonly asyncLocks = new Map<AsyncLockType, AsyncLock>();
  14   private acquired: boolean;
  15   private readonly resolveQueue: Queue<ResolveType>;
  16
  17   private constructor() {
  18     this.acquired = false;
  19     this.resolveQueue = new Queue<ResolveType>();
  20   }
  21
  22   public static async acquire(type: AsyncLockType): Promise<void> {
  23     const asyncLock = AsyncLock.getAsyncLock(type);
  24     if (!asyncLock.acquired) {
  25       asyncLock.acquired = true;
  26       return;
  27     }
  28     return new Promise((resolve) => {
  29       asyncLock.resolveQueue.enqueue(resolve);
  30     });
  31   }
  32
  33   public static async release(type: AsyncLockType): Promise<void> {
  34     const asyncLock = AsyncLock.getAsyncLock(type);
  35     if (asyncLock.resolveQueue.size === 0 && asyncLock.acquired) {
  36       asyncLock.acquired = false;
  37       return;
  38     }
  39     const queuedResolve = asyncLock.resolveQueue.dequeue()!;
  40     return new Promise((resolve) => {
  41       queuedResolve();
  42       resolve();
  43     });
  44   }
  45
  46   private static getAsyncLock(type: AsyncLockType): AsyncLock {
  47     if (!AsyncLock.asyncLocks.has(type)) {
  48       AsyncLock.asyncLocks.set(type, new AsyncLock());
  49     }
  50     return AsyncLock.asyncLocks.get(type)!;
  51   }
  52 }