@tempest/core/lib/scheduler/Scheduler.js

The core of the Tempest Stream Library

import { PredeterminedTask } from './PredeterminedTask';
import { runScheduledTask } from '../util/task';
export class TaskScheduler {
    constructor(timer, timeline) {
        this.timer = timer;
        this.timeline = timeline;
        this._timer = null;
        this._nextArrival = Infinity;
        const self = this;
        this._runReadyTasksBound = () => self._runReadyTasks(self.now());
    }
    now() {
        return this.timer.now();
    }
    asap(task) {
        return this.schedule(0, -1, task);
    }
    delay(delay, task) {
        return this.schedule(delay, -1, task);
    }
    periodic(period, task) {
        return this.schedule(0, period, task);
    }
    schedule(delay, period, task) {
        const time = this.now();
        const st = new PredeterminedTask(+(time) + Math.max(0, delay), period, task, this);
        this.timeline.add(st);
        this._scheduleNextRun(+(time));
        return st;
    }
    cancel(task) {
        task.active = false;
        if (this.timeline.remove(task)) {
            this._reschedule();
        }
    }
    cancelAll(f) {
        this.timeline.removeAll(f);
        this._reschedule();
    }
    _reschedule() {
        if (this.timeline.isEmpty()) {
            this._unschedule();
        }
        else {
            this._scheduleNextRun(this.now());
        }
    }
    _unschedule() {
        this.timer.clearTimer(this._timer);
        this._timer = null;
    }
    _scheduleNextRun(time) {
        if (this.timeline.isEmpty())
            return;
        const nextArrival = this.timeline.nextArrival();
        if (this._timer === null) {
            this._scheduleNextArrival(nextArrival, time);
        }
        else if (nextArrival < this._nextArrival) {
            this._unschedule();
            this._scheduleNextArrival(nextArrival, time);
        }
    }
    _scheduleNextArrival(nextArrival, time) {
        this._nextArrival = nextArrival;
        const delay = Math.max(0, nextArrival - time);
        this._timer = this.timer.setTimer(this._runReadyTasksBound, delay);
    }
    _runReadyTasks(time) {
        this._timer = null;
        this.timeline.runTasks(time, runScheduledTask);
        this._scheduleNextRun(this.now());
    }
}
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