@node-dlc/wire/lib/gossip/GossipSyncWatcher.ts

Lightning Network Wire Protocol

import { ILogger } from '@node-dlc/logger';

import { ChannelAnnouncementMessage } from '../messages/ChannelAnnouncementMessage';
import { ChannelUpdateMessage } from '../messages/ChannelUpdateMessage';
import { NodeAnnouncementMessage } from '../messages/NodeAnnouncementMessage';

export enum GossipSyncWatcherState {
  Idle,
  Watching,
  Complete,
  Canceled,
}

/**
 * GossipSyncWatcher monitors the progress of a GossipSync operation for the
 * completion of the synchronization and signals once the sync has completed
 * or timed out.
 */
export class GossipSyncWatcher {
  public completeAfterMs = 5000;

  private _state: GossipSyncWatcherState;
  private _timeoutHandle: NodeJS.Timeout;
  private _messageCounter: number;

  private _resolve: (value: void) => void;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  private _reject: (reason: any) => void;

  constructor(readonly logger: ILogger) {
    this._state = GossipSyncWatcherState.Idle;
    this._messageCounter = 0;
    // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
    this._onTimeout = this._onTimeout.bind(this);
  }

  /**
   * Gets the state of the Watcher: IDLE, WATCHING, COMPLETE, FAILED
   */
  public get state(): GossipSyncWatcherState {
    return this._state;
  }

  /**
   * Gets the number of messages that have been seen while watching
   */
  public get messageCounter(): number {
    return this._messageCounter;
  }

  /**
   * Watches gossip traffic until a completion event occurs or watching is
   * cancelled.
   */
  public watch(): Promise<void> {
    return new Promise((resolve, reject) => {
      this._state = GossipSyncWatcherState.Watching;
      this._setTimeout();
      this._resolve = resolve;
      this._reject = reject;
    });
  }

  /**
   * Process a message and debounce when it is a gossip message
   * @param msg
   */
  public onGossipMessage(
    // eslint-disable-next-line @typescript-eslint/no-unused-vars
    msg:
      | ChannelAnnouncementMessage
      | ChannelUpdateMessage
      | NodeAnnouncementMessage,
  ): void {
    if (this._state === GossipSyncWatcherState.Watching) {
      this._messageCounter += 1;
      this._clearTimeout();
      this._setTimeout();
    }
  }

  /**
   * Cancels watching and sends a failure signal.
   */
  public cancel(): void {
    if (this._state === GossipSyncWatcherState.Watching) {
      this._clearTimeout();
      this._resolve();
    }
    this._state = GossipSyncWatcherState.Canceled;
  }

  private _clearTimeout() {
    clearTimeout(this._timeoutHandle);
  }

  private _setTimeout() {
    // eslint-disable-next-line @typescript-eslint/unbound-method
    this._timeoutHandle = setTimeout(this._onTimeout, this.completeAfterMs);
  }

  private _onTimeout() {
    this._state = GossipSyncWatcherState.Complete;
    this._resolve();
  }
}