Desktop: Fixes #3729: Fix lock issue when device does not have the right time

ReactNativeClient/lib/ntpDate.ts

@@ -0,0 +1,46 @@
+const ntpClient = require('lib/vendor/ntp-client');
+const Mutex = require('async-mutex').Mutex;
+
+let lastSyncTime = 0;
+let timeOffset = 0;
+const fetchingTimeMutex = new Mutex();
+
+const server = {
+	domain: 'pool.ntp.org',
+	port: 123,
+};
+
+async function networkTime():Promise<Date> {
+	return new Promise(function(resolve:Function, reject:Function) {
+		ntpClient.getNetworkTime(server.domain, server.port, function(error:any, date:Date) {
+			if (error) {
+				reject(error);
+				return;
+			}
+
+			resolve(date);
+		});
+	});
+}
+
+function shouldSyncTime() {
+	return !lastSyncTime || Date.now() - lastSyncTime >= 5 * 1000;
+}
+
+export default async function():Promise<Date> {
+	if (shouldSyncTime()) {
+		const release = await fetchingTimeMutex.acquire();
+
+		try {
+			if (shouldSyncTime()) {
+				const date = await networkTime();
+				lastSyncTime = Date.now();
+				timeOffset = date.getTime() - Date.now();
+			}
+		} finally {
+			release();
+		}
+	}
+
+	return new Date(Date.now() + timeOffset);
+}