mirror of
https://github.com/gristlabs/grist-core.git
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Summary: This moves enough server material into core to run a home server. The data engine is not yet incorporated (though in manual testing it works when ported). Test Plan: existing tests pass Reviewers: dsagal Reviewed By: dsagal Differential Revision: https://phab.getgrist.com/D2552
120 lines
3.2 KiB
TypeScript
120 lines
3.2 KiB
TypeScript
/**
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* InactivityTimer allows to set a function that executes after a certain time of
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* inactivity. Activities can be of two kinds: synchronous or asynchronous. Asynchronous activities,
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* are handle with the `disableUntiFinish` method that takes in a Promise and makes sure that the
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* timer does not start before the promise resolves. Synchroneous activities are monitored with the
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* `ping` method which resets the timer if called during inactivity.
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*
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* Timer won't start before any activity happens, but you may simply call ping() after construction
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* to start it. After cb is called, timer is disabled but enabled again if there is more activity.
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*
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* Example usage: InactivityTimer is used internally for implementing the plugins' component
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* deactivation after a certain time of inactivity.
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*
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*/
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// important to explicitly import this, or webpack --watch gets confused.
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import {clearTimeout, setTimeout} from "timers";
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export class InactivityTimer {
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private _timeout?: NodeJS.Timer | null;
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private _counter: number = 0;
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private _enabled: boolean = true;
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constructor(private _callback: () => void, private _delay: number) {}
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// Returns the delay used by InactivityTimer, in ms.
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public getDelay(): number {
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return this._delay;
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}
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// Sets a different delay to use, in ms.
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public setDelay(delayMs: number): void {
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this._delay = delayMs;
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this.ping();
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}
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/**
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* Enable the InactivityTimer and schedule the callback.
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*/
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public enable(): void {
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this._enabled = true;
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this.ping();
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}
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/**
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* Clears the timeout and prevents the callback from being called until enable() is called.
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*/
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public disable(): void {
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this._enabled = false;
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this._clearTimeout();
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}
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/**
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* Returns whether the InactivityTimer is enabled. If not, the callback will not be scheduled.
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*/
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public isEnabled(): boolean {
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return this._enabled;
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}
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/**
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* Whether the callback is currently scheduled, and would trigger if there is no activity and if
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* it's not disabled before it triggers.
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*/
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public isScheduled(): boolean {
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return Boolean(this._timeout);
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}
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/**
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* Resets the timer if called during inactivity.
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*/
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public ping() {
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if (!this._counter && this._enabled) {
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this._setTimeout();
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}
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}
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/**
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* The `disableUntilFinish` method takes in a promise and makes sure the timer won't start before
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* it resolves. It returns a promise that resolves to the same object.
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*/
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public async disableUntilFinish<T>(promise: Promise<T>): Promise<T> {
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this._beginActivity();
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try {
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return await promise;
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} finally {
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this._endActivity();
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}
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}
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private _beginActivity() {
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this._counter++;
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this._clearTimeout();
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}
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private _endActivity() {
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this._counter = Math.max(this._counter - 1, 0);
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this.ping();
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}
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private _clearTimeout() {
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if (this._timeout) {
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clearTimeout(this._timeout);
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this._timeout = null;
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}
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}
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private _setTimeout() {
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this._clearTimeout();
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this._timeout = setTimeout(() => this._onTimeoutTriggered(), this._delay);
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}
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private _onTimeoutTriggered() {
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this._clearTimeout();
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// _counter is set to 0, even if there's no reason why it should be any thing else.
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this._counter = 0;
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this._callback();
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}
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}
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