molstar
Version:
A comprehensive macromolecular library.
42 lines (41 loc) • 1.19 kB
JavaScript
/**
* Copyright (c) 2022 mol* contributors, licensed under MIT, See LICENSE file for more info.
*
* @author Adam Midlik <midlik@gmail.com>
*/
/** Job queue that allows at most one running and one pending job.
* A newly enqueued job will cancel any other pending jobs. */
export class SingleAsyncQueue {
constructor(log = false) {
this.isRunning = false;
this.queue = [];
this.counter = 0;
this.log = log;
}
enqueue(job) {
if (this.log)
console.log('SingleAsyncQueue enqueue', this.counter);
this.queue[0] = { id: this.counter, func: job };
this.counter++;
this.run(); // do not await
}
async run() {
if (this.isRunning)
return;
const job = this.queue.pop();
if (!job)
return;
this.isRunning = true;
try {
if (this.log)
console.log('SingleAsyncQueue run', job.id);
await job.func();
if (this.log)
console.log('SingleAsyncQueue complete', job.id);
}
finally {
this.isRunning = false;
this.run();
}
}
}