55 lines
1.4 KiB
TypeScript
55 lines
1.4 KiB
TypeScript
// Copyright 2018-2022 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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import EventEmitter from 'events';
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import * as log from './logging/log';
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import { clearTimeoutIfNecessary } from './util/clearTimeoutIfNecessary';
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const POLL_INTERVAL_MS = 5 * 1000;
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const IDLE_THRESHOLD_MS = 20;
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export class IdleDetector extends EventEmitter {
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private handle: undefined | ReturnType<typeof requestIdleCallback>;
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private timeoutId: undefined | ReturnType<typeof setTimeout>;
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public start(): void {
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log.info('Start idle detector');
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this.scheduleNextCallback();
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}
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public stop(): void {
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if (!this.handle) {
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return;
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}
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log.info('Stop idle detector');
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this.clearScheduledCallbacks();
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}
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private clearScheduledCallbacks() {
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if (this.handle) {
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cancelIdleCallback(this.handle);
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delete this.handle;
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}
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clearTimeoutIfNecessary(this.timeoutId);
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delete this.timeoutId;
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}
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private scheduleNextCallback() {
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this.clearScheduledCallbacks();
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this.handle = window.requestIdleCallback(deadline => {
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const { didTimeout } = deadline;
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const timeRemaining = deadline.timeRemaining();
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const isIdle = timeRemaining >= IDLE_THRESHOLD_MS;
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this.timeoutId = setTimeout(
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() => this.scheduleNextCallback(),
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POLL_INTERVAL_MS
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);
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if (isIdle || didTimeout) {
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this.emit('idle', { timestamp: Date.now(), didTimeout, timeRemaining });
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}
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});
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}
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}
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