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src/vs/base/common/event.ts 839 introduced LOC · 93 ranges

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1 > /*--------------------------------------------------------------------------------------------- event.ts
2 > * Copyright (c) Microsoft Corporation. All rights reserved.
3 > * Licensed under the MIT License. See License.txt in the project root for license information.
4 > *--------------------------------------------------------------------------------------------*/
5 >
6 > import { CancelablePromise } from './async.js';
7 > import { CancellationToken } from './cancellation.js';
8 > import { diffSets } from './collections.js';
9 > import { onUnexpectedError } from './errors.js';
10 > import { createSingleCallFunction } from './functional.js';
11 > import { combinedDisposable, Disposable, DisposableMap, DisposableStore, IDisposable, toDisposable } from './lifecycle.js';
12 > import { LinkedList } from './linkedList.js';
13 > import { IObservable, IObservableWithChange, IObserver } from './observable.js';
14 > import { env } from './process.js';
15 > import { StopWatch } from './stopwatch.js';
16 > import { MicrotaskDelay } from './symbols.js';
17 >
18 >
19 > // -----------------------------------------------------------------------------------------------------------------------
20 > // Uncomment the next line to print warnings whenever an emitter with listeners is disposed. That is a sign of code smell.
21 > // -----------------------------------------------------------------------------------------------------------------------
22 > const _enableDisposeWithListenerWarning = false
23 > // || Boolean("TRUE") // causes a linter warning so that it cannot be pushed
24 > ;
25 >
26 >
27 > // -----------------------------------------------------------------------------------------------------------------------
28 > // Uncomment the next line to print warnings whenever a snapshotted event is used repeatedly without cleanup.
29 > // See https://github.com/microsoft/vscode/issues/142851
30 > // -----------------------------------------------------------------------------------------------------------------------
31 > const _enableSnapshotPotentialLeakWarning = false
32 > // || Boolean("TRUE") // causes a linter warning so that it cannot be pushed
33 > ;
34 >
35 >
36 > const _bufferLeakWarnCountThreshold = 100;
37 > const _bufferLeakWarnTimeThreshold = 60_000; // 1 minute
38 >
39 function _isBufferLeakWarningEnabled(): boolean {
40 return !!env['VSCODE_DEV'];
41 }
42 > event.ts
43 > /**
44 > * An event with zero or one parameters that can be subscribed to. The event is a function itself.
45 > */
46 > export interface Event<T> {
47 > (listener: (e: T) => unknown, thisArgs?: any, disposables?: IDisposable[] | DisposableStore): IDisposable;
48 > }
49 >
50 > export namespace Event {
51 > export const None: Event<any> = () => Disposable.None;
52 >
53 > function _addLeakageTraceLogic(options: EmitterOptions) {
54 if (_enableSnapshotPotentialLeakWarning) {
55 const { onDidAddListener: origListenerDidAdd } = options;
65 }
66 }
67 > event.ts
68 > /**
69 > * Given an event, returns another event which debounces calls and defers the listeners to a later task via a shared
70 > * `setTimeout`. The event is converted into a signal (`Event<void>`) to avoid additional object creation as a
71 > * result of merging events and to try prevent race conditions that could arise when using related deferred and
72 > * non-deferred events.
73 > *
74 > * This is useful for deferring non-critical work (eg. general UI updates) to ensure it does not block critical work
75 > * (eg. latency of keypress to text rendered).
76 > *
77 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
78 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
79 > * returned event causes this utility to leak a listener on the original event.
80 > *
81 > * @param event The event source for the new event.
82 > * @param flushOnListenerRemove Whether to fire all debounced events when a listener is removed. If this is not
83 > * specified, some events could go missing. Use this if it's important that all events are processed, even if the
84 > * listener gets disposed before the debounced event fires.
85 > * @param disposable A disposable store to add the new EventEmitter to.
86 > */
87 > export function defer(event: Event<unknown>, flushOnListenerRemove?: boolean, disposable?: DisposableStore): Event<void> {
88 return debounce<unknown, void>(event, () => void 0, 0, undefined, flushOnListenerRemove ?? true, undefined, disposable);
89 }
90 > event.ts
91 > /**
92 > * Given an event, returns another event which only fires once.
93 > *
94 > * @param event The event source for the new event.
95 > */
96 > export function once<T>(event: Event<T>): Event<T> {
97 return (listener, thisArgs = null, disposables?) => {
98 // we need this, in case the event fires during the listener call
118 };
119 }
120 > event.ts
121 > /**
122 > * Given an event, returns another event which only fires once, and only when the condition is met.
123 > *
124 > * @param event The event source for the new event.
125 > */
126 > export function onceIf<T>(event: Event<T>, condition: (e: T) => boolean): Event<T> {
127 return Event.once(Event.filter(event, condition));
128 }
129 > event.ts
130 > /**
131 > * Maps an event of one type into an event of another type using a mapping function, similar to how
132 > * `Array.prototype.map` works.
133 > *
134 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
135 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
136 > * returned event causes this utility to leak a listener on the original event.
137 > *
138 > * @param event The event source for the new event.
139 > * @param map The mapping function.
140 > * @param disposable A disposable store to add the new EventEmitter to.
141 > */
142 > export function map<I, O>(event: Event<I>, map: (i: I) => O, disposable?: DisposableStore): Event<O> {
143 return snapshot((listener, thisArgs = null, disposables?) => event(i => listener.call(thisArgs, map(i)), null, disposables), disposable);
144 }
145 > event.ts
146 > /**
147 > * Wraps an event in another event that performs some function on the event object before firing.
148 > *
149 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
150 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
151 > * returned event causes this utility to leak a listener on the original event.
152 > *
153 > * @param event The event source for the new event.
154 > * @param each The function to perform on the event object.
155 > * @param disposable A disposable store to add the new EventEmitter to.
156 > */
157 > export function forEach<I>(event: Event<I>, each: (i: I) => void, disposable?: DisposableStore): Event<I> {
158 return snapshot((listener, thisArgs = null, disposables?) => event(i => { each(i); listener.call(thisArgs, i); }, null, disposables), disposable);
159 }
160 > event.ts
161 > /**
162 > * Wraps an event in another event that fires only when some condition is met.
163 > *
164 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
165 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
166 > * returned event causes this utility to leak a listener on the original event.
167 > *
168 > * @param event The event source for the new event.
169 > * @param filter The filter function that defines the condition. The event will fire for the object if this function
170 > * returns true.
171 > * @param disposable A disposable store to add the new EventEmitter to.
172 > */
173 > export function filter<T, U>(event: Event<T | U>, filter: (e: T | U) => e is T, disposable?: DisposableStore): Event<T>;
174 > export function filter<T>(event: Event<T>, filter: (e: T) => boolean, disposable?: DisposableStore): Event<T>;
175 > export function filter<T, R>(event: Event<T | R>, filter: (e: T | R) => e is R, disposable?: DisposableStore): Event<R>;
176 > export function filter<T>(event: Event<T>, filter: (e: T) => boolean, disposable?: DisposableStore): Event<T> {
177 return snapshot((listener, thisArgs = null, disposables?) => event(e => filter(e) && listener.call(thisArgs, e), null, disposables), disposable);
178 }
179 > event.ts
180 > /**
181 > * Given an event, returns the same event but typed as `Event<void>`.
182 > */
183 > export function signal<T>(event: Event<T>): Event<void> {
184 return event as Event<any> as Event<void>;
185 }
186 > event.ts
187 > /**
188 > * Given a collection of events, returns a single event which emits whenever any of the provided events emit.
189 > */
190 > export function any<T>(...events: Event<T>[]): Event<T>;
191 > export function any(...events: Event<any>[]): Event<void>;
192 > export function any<T>(...events: Event<T>[]): Event<T> {
193 return (listener, thisArgs = null, disposables?) => {
194 const disposable = combinedDisposable(...events.map(event => event(e => listener.call(thisArgs, e))));
196 };
197 }
198 > event.ts
199 > /**
200 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
201 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
202 > * returned event causes this utility to leak a listener on the original event.
203 > */
204 > export function reduce<I, O>(event: Event<I>, merge: (last: O | undefined, event: I) => O, initial?: O, disposable?: DisposableStore): Event<O> {
205 let output: O | undefined = initial;
206
210 }, disposable);
211 }
212 > event.ts
213 > function snapshot<T>(event: Event<T>, disposable: DisposableStore | undefined): Event<T> {
214 let listener: IDisposable | undefined;
215
233 return emitter.event;
234 }
235 > event.ts
236 > /**
237 > * Adds the IDisposable to the store if it's set, and returns it. Useful to
238 > * Event function implementation.
239 > */
240 > function addAndReturnDisposable<T extends IDisposable>(d: T, store: DisposableStore | IDisposable[] | undefined): T {
241 if (store instanceof Array) {
242 store.push(d);
246 return d;
247 }
248 > event.ts
249 > /**
250 > * Given an event, creates a new emitter that event that will debounce events based on {@link delay} and give an
251 > * array event object of all events that fired.
252 > *
253 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
254 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
255 > * returned event causes this utility to leak a listener on the original event.
256 > *
257 > * @param event The original event to debounce.
258 > * @param merge A function that reduces all events into a single event.
259 > * @param delay The number of milliseconds to debounce.
260 > * @param leading Whether to fire a leading event without debouncing.
261 > * @param flushOnListenerRemove Whether to fire all debounced events when a listener is removed. If this is not
262 > * specified, some events could go missing. Use this if it's important that all events are processed, even if the
263 > * listener gets disposed before the debounced event fires.
264 > * @param leakWarningThreshold See {@link EmitterOptions.leakWarningThreshold}.
265 > * @param disposable A disposable store to register the debounce emitter to.
266 > */
267 > export function debounce<T>(event: Event<T>, merge: (last: T | undefined, event: T) => T, delay?: number | typeof MicrotaskDelay, leading?: boolean, flushOnListenerRemove?: boolean, leakWarningThreshold?: number, disposable?: DisposableStore): Event<T>;
268 > export function debounce<I, O>(event: Event<I>, merge: (last: O | undefined, event: I) => O, delay?: number | typeof MicrotaskDelay, leading?: boolean, flushOnListenerRemove?: boolean, leakWarningThreshold?: number, disposable?: DisposableStore): Event<O>;
269 > export function debounce<I, O>(event: Event<I>, merge: (last: O | undefined, event: I) => O, delay: number | typeof MicrotaskDelay = 100, leading = false, flushOnListenerRemove = false, leakWarningThreshold?: number, disposable?: DisposableStore): Event<O> {
270 let subscription: IDisposable;
271 let output: O | undefined = undefined;
330 return emitter.event;
331 }
332 > event.ts
333 > /**
334 > * Debounces an event, firing after some delay (default=0) with an array of all event original objects.
335 > *
336 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
337 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
338 > * returned event causes this utility to leak a listener on the original event.
339 > *
340 > * @param event The event source for the new event.
341 > * @param delay The number of milliseconds to debounce.
342 > * @param flushOnListenerRemove Whether to fire all debounced events when a listener is removed. If this is not
343 > * specified, some events could go missing. Use this if it's important that all events are processed, even if the
344 > * listener gets disposed before the debounced event fires.
345 > * @param disposable A disposable store to add the new EventEmitter to.
346 > */
347 > export function accumulate<T>(event: Event<T>, delay: number | typeof MicrotaskDelay = 0, flushOnListenerRemove?: boolean, disposable?: DisposableStore): Event<T[]> {
348 return Event.debounce<T, T[]>(event, (last, e) => {
349 if (!last) {
354 }, delay, undefined, flushOnListenerRemove ?? true, undefined, disposable);
355 }
356 > event.ts
357 > /**
358 > * Throttles an event, ensuring the event is fired at most once during the specified delay period.
359 > * Unlike debounce, throttle will fire immediately on the leading edge and/or after the delay on the trailing edge.
360 > *
361 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
362 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
363 > * returned event causes this utility to leak a listener on the original event.
364 > *
365 > * @param event The event source for the new event.
366 > * @param merge An accumulator function that merges events if multiple occur during the throttle period.
367 > * @param delay The number of milliseconds to throttle.
368 > * @param leading Whether to fire on the leading edge (immediately on first event).
369 > * @param trailing Whether to fire on the trailing edge (after delay with the last value).
370 > * @param leakWarningThreshold See {@link EmitterOptions.leakWarningThreshold}.
371 > * @param disposable A disposable store to register the throttle emitter to.
372 > */
373 > export function throttle<T>(event: Event<T>, merge: (last: T | undefined, event: T) => T, delay?: number | typeof MicrotaskDelay, leading?: boolean, trailing?: boolean, leakWarningThreshold?: number, disposable?: DisposableStore): Event<T>;
374 > export function throttle<I, O>(event: Event<I>, merge: (last: O | undefined, event: I) => O, delay?: number | typeof MicrotaskDelay, leading?: boolean, trailing?: boolean, leakWarningThreshold?: number, disposable?: DisposableStore): Event<O>;
375 > export function throttle<I, O>(event: Event<I>, merge: (last: O | undefined, event: I) => O, delay: number | typeof MicrotaskDelay = 100, leading = true, trailing = true, leakWarningThreshold?: number, disposable?: DisposableStore): Event<O> {
376 let subscription: IDisposable;
377 let output: O | undefined = undefined;
437 return emitter.event;
438 }
439 > event.ts
440 > /**
441 > * Filters an event such that some condition is _not_ met more than once in a row, effectively ensuring duplicate
442 > * event objects from different sources do not fire the same event object.
443 > *
444 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
445 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
446 > * returned event causes this utility to leak a listener on the original event.
447 > *
448 > * @param event The event source for the new event.
449 > * @param equals The equality condition.
450 > * @param disposable A disposable store to add the new EventEmitter to.
451 > *
452 > * @example
453 > * ```
454 > * // Fire only one time when a single window is opened or focused
455 > * Event.latch(Event.any(onDidOpenWindow, onDidFocusWindow))
456 > * ```
457 > */
458 > export function latch<T>(event: Event<T>, equals: (a: T, b: T) => boolean = (a, b) => a === b, disposable?: DisposableStore): Event<T> {
459 let firstCall = true;
460 let cache: T;
467 }, disposable);
468 }
469 > event.ts
470 > /**
471 > * Splits an event whose parameter is a union type into 2 separate events for each type in the union.
472 > *
473 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
474 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
475 > * returned event causes this utility to leak a listener on the original event.
476 > *
477 > * @example
478 > * ```
479 > * const event = new EventEmitter<number | undefined>().event;
480 > * const [numberEvent, undefinedEvent] = Event.split(event, isUndefined);
481 > * ```
482 > *
483 > * @param event The event source for the new event.
484 > * @param isT A function that determines what event is of the first type.
485 > * @param disposable A disposable store to add the new EventEmitter to.
486 > */
487 > export function split<T, U>(event: Event<T | U>, isT: (e: T | U) => e is T, disposable?: DisposableStore): [Event<T>, Event<U>] {
488 return [
489 Event.filter(event, isT, disposable),
491 ];
492 }
493 > event.ts
494 > /**
495 > * Buffers an event until it has a listener attached.
496 > *
497 > * *NOTE* that this function returns an `Event` and it MUST be called with a `DisposableStore` whenever the returned
498 > * event is accessible to "third parties", e.g the event is a public property. Otherwise a leaked listener on the
499 > * returned event causes this utility to leak a listener on the original event.
500 > *
501 > * @param event The event source for the new event.
502 > * @param debugName A name for this buffer, used in leak detection warnings.
503 > * @param flushAfterTimeout Determines whether to flush the buffer after a timeout immediately or after a
504 > * `setTimeout` when the first event listener is added.
505 > * @param _buffer Internal: A source event array used for tests.
506 > *
507 > * @example
508 > * ```
509 > * // Start accumulating events, when the first listener is attached, flush
510 > * // the event after a timeout such that multiple listeners attached before
511 > * // the timeout would receive the event
512 > * this.onInstallExtension = Event.buffer(service.onInstallExtension, 'onInstallExtension', true);
513 > * ```
514 > */
515 > export function buffer<T>(event: Event<T>, debugName: string, flushAfterTimeout = false, _buffer: T[] = [], disposable?: DisposableStore): Event<T> {
516 let buffer: T[] | null = _buffer.slice();
517
600 return emitter.event;
601 }
602 > /** event.ts
603 > * Wraps the event in an {@link IChainableEvent}, allowing a more functional programming style.
604 > *
605 > * @example
606 > * ```
607 > * // Normal
608 > * const onEnterPressNormal = Event.filter(
609 > * Event.map(onKeyPress.event, e => new StandardKeyboardEvent(e)),
610 > * e.keyCode === KeyCode.Enter
611 > * ).event;
612 > *
613 > * // Using chain
614 > * const onEnterPressChain = Event.chain(onKeyPress.event, $ => $
615 > * .map(e => new StandardKeyboardEvent(e))
616 > * .filter(e => e.keyCode === KeyCode.Enter)
617 > * );
618 > * ```
619 > */
620 > export function chain<T, R>(event: Event<T>, sythensize: ($: IChainableSythensis<T>) => IChainableSythensis<R>): Event<R> {
621 const fn: Event<R> = (listener, thisArgs, disposables) => {
622 const cs = sythensize(new ChainableSynthesis()) as ChainableSynthesis;
631 return fn;
632 }
633 > event.ts
634 > const HaltChainable = Symbol('HaltChainable');
635 >
636 > class ChainableSynthesis implements IChainableSythensis<any> {
637 private readonly steps: ((input: any) => unknown)[] = [];
638 > event.ts
639 > map<O>(fn: (i: any) => O): this {
640 this.steps.push(fn);
641 return this;
642 }
643 > event.ts
644 > forEach(fn: (i: any) => void): this {
645 this.steps.push(v => {
646 fn(v);
649 return this;
650 }
651 > event.ts
652 > filter(fn: (e: any) => boolean): this {
653 this.steps.push(v => fn(v) ? v : HaltChainable);
654 return this;
655 }
656 > event.ts
657 > reduce<R>(merge: (last: R | undefined, event: any) => R, initial?: R | undefined): this {
658 let last = initial;
659 this.steps.push(v => {
663 return this;
664 }
665 > event.ts
666 > latch(equals: (a: any, b: any) => boolean = (a, b) => a === b): ChainableSynthesis {
667 let firstCall = true;
668 let cache: any;
676 return this;
677 }
678 > event.ts
679 > public evaluate(value: any) {
680 for (const step of this.steps) {
681 value = step(value);
687 return value;
688 }
689 > } event.ts
690 >
691 > export interface IChainableSythensis<T> {
692 > map<O>(fn: (i: T) => O): IChainableSythensis<O>;
693 > forEach(fn: (i: T) => void): IChainableSythensis<T>;
694 > filter<R extends T>(fn: (e: T) => e is R): IChainableSythensis<R>;
695 > filter(fn: (e: T) => boolean): IChainableSythensis<T>;
696 > reduce<R>(merge: (last: R, event: T) => R, initial: R): IChainableSythensis<R>;
697 > reduce<R>(merge: (last: R | undefined, event: T) => R): IChainableSythensis<R>;
698 > latch(equals?: (a: T, b: T) => boolean): IChainableSythensis<T>;
699 > }
700 >
701 > export interface NodeEventEmitter {
702 > on(event: string | symbol, listener: Function): unknown;
703 > removeListener(event: string | symbol, listener: Function): unknown;
704 > }
705 >
706 > /**
707 > * Creates an {@link Event} from a node event emitter.
708 > */
709 > export function fromNodeEventEmitter<T>(emitter: NodeEventEmitter, eventName: string, map: (...args: any[]) => T = id => id): Event<T> {
710 const fn = (...args: unknown[]) => result.fire(map(...args));
711 const onFirstListenerAdd = () => emitter.on(eventName, fn);
715 return result.event;
716 }
717 > event.ts
718 > export interface DOMEventEmitter {
719 > addEventListener(event: string | symbol, listener: Function): void;
720 > removeEventListener(event: string | symbol, listener: Function): void;
721 > }
722 >
723 > /**
724 > * Creates an {@link Event} from a DOM event emitter.
725 > */
726 > export function fromDOMEventEmitter<T>(emitter: DOMEventEmitter, eventName: string, map: (...args: any[]) => T = id => id): Event<T> {
727 const fn = (...args: unknown[]) => result.fire(map(...args));
728 const onFirstListenerAdd = () => emitter.addEventListener(eventName, fn);
732 return result.event;
733 }
734 > event.ts
735 > /**
736 > * Creates a promise out of an event, using the {@link Event.once} helper.
737 > */
738 > export function toPromise<T>(event: Event<T>, disposables?: IDisposable[] | DisposableStore): CancelablePromise<T> {
739 let cancelRef: () => void;
740 let listener: IDisposable;
756 return promise;
757 }
758 > event.ts
759 > /**
760 > * A convenience function for forwarding an event to another emitter which
761 > * improves readability.
762 > *
763 > * This is similar to {@link Relay} but allows instantiating and forwarding
764 > * on a single line and also allows for multiple source events.
765 > * @param from The event to forward.
766 > * @param to The emitter to forward the event to.
767 > * @example
768 > * Event.forward(event, emitter);
769 > * // equivalent to
770 > * event(e => emitter.fire(e));
771 > * // equivalent to
772 > * event(emitter.fire, emitter);
773 > */
774 > export function forward<T>(from: Event<T>, to: Emitter<T>): IDisposable {
775 return from(e => to.fire(e));
776 }
777 > event.ts
778 > /**
779 > * Adds a listener to an event and calls the listener immediately with undefined as the event object.
780 > *
781 > * @example
782 > * ```
783 > * // Initialize the UI and update it when dataChangeEvent fires
784 > * runAndSubscribe(dataChangeEvent, () => this._updateUI());
785 > * ```
786 > */
787 > export function runAndSubscribe<T>(event: Event<T>, handler: (e: T) => unknown, initial: T): IDisposable;
788 > export function runAndSubscribe<T>(event: Event<T>, handler: (e: T | undefined) => unknown): IDisposable;
789 > export function runAndSubscribe<T>(event: Event<T>, handler: (e: T | undefined) => unknown, initial?: T): IDisposable {
790 handler(initial);
791 return event(e => handler(e));
792 }
793 > event.ts
794 > class EmitterObserver<T> implements IObserver {
795 >
796 > readonly emitter: Emitter<T>;
797 >
798 > private _counter = 0;
799 > private _hasChanged = false;
800 >
801 > constructor(readonly _observable: IObservable<T>, store: DisposableStore | undefined) {
802 const options: EmitterOptions = {
803 onWillAddFirstListener: () => {
819 }
820 }
821 > event.ts
822 > beginUpdate<T>(_observable: IObservable<T>): void {
823 // assert(_observable === this.obs);
824 this._counter++;
825 }
826 > event.ts
827 > handlePossibleChange<T>(_observable: IObservable<T>): void {
828 // assert(_observable === this.obs);
829 }
830 > event.ts
831 > handleChange<T, TChange>(_observable: IObservableWithChange<T, TChange>, _change: TChange): void {
832 // assert(_observable === this.obs);
833 this._hasChanged = true;
834 }
835 > event.ts
836 > endUpdate<T>(_observable: IObservable<T>): void {
837 // assert(_observable === this.obs);
838 this._counter--;
845 }
846 }
847 > } event.ts
848 >
849 > /**
850 > * Creates an event emitter that is fired when the observable changes.
851 > * Each listeners subscribes to the emitter.
852 > */
853 > export function fromObservable<T>(obs: IObservable<T>, store?: DisposableStore): Event<T> {
854 const observer = new EmitterObserver(obs, store);
855 return observer.emitter.event;
856 }
857 > event.ts
858 > /**
859 > * Each listener is attached to the observable directly.
860 > */
861 > export function fromObservableLight(observable: IObservable<unknown>): Event<void> {
862 return (listener, thisArgs, disposables) => {
863 let count = 0;
897 };
898 }
899 > } event.ts
900 >
901 > export interface EmitterOptions {
902 > /**
903 > * Optional function that's called *before* the very first listener is added
904 > */
905 > onWillAddFirstListener?: Function;
906 > /**
907 > * Optional function that's called *after* the very first listener is added
908 > */
909 > onDidAddFirstListener?: Function;
910 > /**
911 > * Optional function that's called after a listener is added
912 > */
913 > onDidAddListener?: Function;
914 > /**
915 > * Optional function that's called *after* remove the very last listener
916 > */
917 > onDidRemoveLastListener?: Function;
918 > /**
919 > * Optional function that's called *before* a listener is removed
920 > */
921 > onWillRemoveListener?: Function;
922 > /**
923 > * Optional function that's called when a listener throws an error. Defaults to
924 > * {@link onUnexpectedError}
925 > */
926 > onListenerError?: (e: any) => void;
927 > /**
928 > * Number of listeners that are allowed before assuming a leak. Default to
929 > * a globally configured value
930 > *
931 > * @see setGlobalLeakWarningThreshold
932 > */
933 > leakWarningThreshold?: number;
934 > /**
935 > * Human-readable name for the emitter, included in leak warning error
936 > * messages to help identify which emitter is leaking in telemetry.
937 > */
938 > leakWarningName?: string;
939 > /**
940 > * Pass in a delivery queue, which is useful for ensuring
941 > * in order event delivery across multiple emitters.
942 > */
943 > deliveryQueue?: EventDeliveryQueue;
944 >
945 > /** ONLY enable this during development */
946 > _profName?: string;
947 > }
948 >
949 >
950 > export class EventProfiling {
951 >
952 > static readonly all = new Set<EventProfiling>();
953 >
954 > private static _idPool = 0;
955 >
956 > readonly name: string;
957 > public listenerCount: number = 0;
958 > public invocationCount = 0;
959 > public elapsedOverall = 0;
960 > public durations: number[] = [];
961 >
962 > private _stopWatch?: StopWatch;
963 >
964 > constructor(name: string) {
965 this.name = `${name}_${EventProfiling._idPool++}`;
966 EventProfiling.all.add(this);
967 }
968 > event.ts
969 > start(listenerCount: number): void {
970 this._stopWatch = new StopWatch();
971 this.listenerCount = listenerCount;
972 }
973 > event.ts
974 > stop(): void {
975 if (this._stopWatch) {
976 const elapsed = this._stopWatch.elapsed();
981 }
982 }
983 > } event.ts
984 >
985 > let _globalLeakWarningThreshold = -1;
986 > export function setGlobalLeakWarningThreshold(n: number): IDisposable {
987 const oldValue = _globalLeakWarningThreshold;
988 _globalLeakWarningThreshold = n;
993 };
994 }
995 > event.ts
996 > class LeakageMonitor {
997 >
998 > private static _idPool = 1;
999 >
1000 > private _stacks: Map<string, number> | undefined;
1001 > private _warnCountdown: number = 0;
1002 >
1003 > constructor(
1004 private readonly _errorHandler: (err: Error) => void,
1005 readonly threshold: number,
1006 readonly name: string = (LeakageMonitor._idPool++).toString(16).padStart(3, '0')
1007 ) { }
1008 > event.ts
1009 > dispose(): void {
1010 this._stacks?.clear();
1011 }
1012 > event.ts
1013 > check(stack: Stacktrace, listenerCount: number): undefined | (() => void) {
1014
1015 const threshold = this.threshold;
1046 };
1047 }
1048 > event.ts
1049 > getMostFrequentStack(): [string, number] | undefined {
1050 if (!this._stacks) {
1051 return undefined;
1061 return topStack;
1062 }
1063 > } event.ts
1064 >
1065 > class Stacktrace {
1066 >
1067 > static create() {
1068 > const err = new Error();
1069 > return new Stacktrace(err.stack ?? '');
1070 > }
1071 >
1072 > private constructor(readonly value: string) { }
1073 >
1074 > print() {
1075 console.warn(this.value.split('\n').slice(2).join('\n'));
1076 }
1077 > } event.ts
1078 >
1079 > // error that is logged when going over the configured listener threshold
1080 > export class ListenerLeakError extends Error {
1081 > readonly kind: string;
1082 > readonly listenerCount: number;
1083 > /**
1084 > * The detailed message including listener count and most frequent stack.
1085 > * Available locally for debugging but intentionally not used as the error
1086 > * `message`. When `emitterName` is provided, errors group by emitter name
1087 > * and kind in telemetry; otherwise they group by kind alone.
1088 > */
1089 > readonly details: string;
1090 > constructor(kind: 'dominated' | 'popular', details: string, stack: string, listenerCount: number, emitterName?: string) {
1091 super(emitterName
1092 ? `[${emitterName}] potential listener LEAK detected, ${kind}`
1098 this.stack = stack;
1099 }
1100 > event.ts
1101 > static is(err: unknown): err is ListenerLeakError {
1102 return err instanceof ListenerLeakError
1103 || (err instanceof Error && typeof (err as Error & { kind: unknown; listenerCount: unknown }).kind === 'string' && typeof (err as Error & { kind: unknown; listenerCount: unknown }).listenerCount === 'number');
1104 }
1105 > } event.ts
1106 >
1107 > // SEVERE error that is logged when having gone way over the configured listener
1108 > // threshold so that the emitter refuses to accept more listeners
1109 > export class ListenerRefusalError extends ListenerLeakError {
1110 > constructor(kind: 'dominated' | 'popular', details: string, stack: string, listenerCount: number, emitterName?: string) {
1111 super(kind, details, stack, listenerCount, emitterName);
1112 this.name = 'ListenerRefusalError';
1113 }
1114 > } event.ts
1115 >
1116 > let id = 0;
1117 > class UniqueContainer<T> {
1118 > stack?: Stacktrace;
1119 > public id = id++;
1120 > constructor(public readonly value: T) { }
1121 > }
1122 > const compactionThreshold = 2;
1123 >
1124 > type ListenerContainer<T> = UniqueContainer<(data: T) => void>;
1125 > type ListenerOrListeners<T> = (ListenerContainer<T> | undefined)[] | ListenerContainer<T>;
1126 >
1127 > const forEachListener = <T>(listeners: ListenerOrListeners<T>, fn: (c: ListenerContainer<T>) => void) => {
1128 if (listeners instanceof UniqueContainer) {
1129 fn(listeners);
1137 }
1138 };
1139 > event.ts
1140 > /**
1141 > * The Emitter can be used to expose an Event to the public
1142 > * to fire it from the insides.
1143 > * Sample:
1144 > class Document {
1145 >
1146 > private readonly _onDidChange = new Emitter<(value:string)=>any>();
1147 >
1148 > public onDidChange = this._onDidChange.event;
1149 >
1150 > // getter-style
1151 > // get onDidChange(): Event<(value:string)=>any> {
1152 > // return this._onDidChange.event;
1153 > // }
1154 >
1155 > private _doIt() {
1156 > //...
1157 > this._onDidChange.fire(value);
1158 > }
1159 > }
1160 > */
1161 > export class Emitter<T> {
1162 >
1163 > private readonly _options?: EmitterOptions;
1164 > private readonly _leakageMon?: LeakageMonitor;
1165 > private readonly _perfMon?: EventProfiling;
1166 > private _disposed?: true;
1167 > private _event?: Event<T>;
1168 >
1169 > /**
1170 > * A listener, or list of listeners. A single listener is the most common
1171 > * for event emitters (#185789), so we optimize that special case to avoid
1172 > * wrapping it in an array (just like Node.js itself.)
1173 > *
1174 > * A list of listeners never 'downgrades' back to a plain function if
1175 > * listeners are removed, for two reasons:
1176 > *
1177 > * 1. That's complicated (especially with the deliveryQueue)
1178 > * 2. A listener with >1 listener is likely to have >1 listener again at
1179 > * some point, and swapping between arrays and functions may[citation needed]
1180 > * introduce unnecessary work and garbage.
1181 > *
1182 > * The array listeners can be 'sparse', to avoid reallocating the array
1183 > * whenever any listener is added or removed. If more than `1 / compactionThreshold`
1184 > * of the array is empty, only then is it resized.
1185 > */
1186 > protected _listeners?: ListenerOrListeners<T>;
1187 >
1188 > /**
1189 > * Always to be defined if _listeners is an array. It's no longer a true
1190 > * queue, but holds the dispatching 'state'. If `fire()` is called on an
1191 > * emitter, any work left in the _deliveryQueue is finished first.
1192 > */
1193 > private _deliveryQueue?: EventDeliveryQueuePrivate;
1194 > protected _size = 0;
1195 >
1196 > constructor(options?: EmitterOptions) {
1197 this._options = options;
1198 this._leakageMon = (_globalLeakWarningThreshold > 0 || this._options?.leakWarningThreshold)
1202 this._deliveryQueue = this._options?.deliveryQueue as EventDeliveryQueuePrivate | undefined;
1203 }
1204 > event.ts
1205 > dispose() {
1206 if (!this._disposed) {
1207 this._disposed = true;
1235 }
1236 }
1237 > event.ts
1238 > /**
1239 > * For the public to allow to subscribe
1240 > * to events from this Emitter
1241 > */
1242 > get event(): Event<T> {
1243 this._event ??= (callback: (e: T) => unknown, thisArgs?: any, disposables?: IDisposable[] | DisposableStore) => {
1244 if (this._leakageMon && this._size > this._leakageMon.threshold ** 2) {
1304 return this._event;
1305 }
1306 > event.ts
1307 > private _removeListener(listener: ListenerContainer<T>) {
1308 this._options?.onWillRemoveListener?.(this);
1309
1349 }
1350 }
1351 > event.ts
1352 > private _deliver(listener: undefined | UniqueContainer<(value: T) => void>, value: T) {
1353 if (!listener) {
1354 return;
1367 }
1368 }
1369 > event.ts
1370 > /** Delivers items in the queue. Assumes the queue is ready to go. */
1371 > private _deliverQueue(dq: EventDeliveryQueuePrivate) {
1372 const listeners = dq.current!._listeners! as (ListenerContainer<T> | undefined)[];
1373 while (dq.i < dq.end) {
1377 dq.reset();
1378 }
1379 > event.ts
1380 > /**
1381 > * To be kept private to fire an event to
1382 > * subscribers
1383 > */
1384 > fire(event: T): void {
1385 if (this._deliveryQueue?.current) {
1386 this._deliverQueue(this._deliveryQueue);
1402 this._perfMon?.stop();
1403 }
1404 > event.ts
1405 > hasListeners(): boolean {
1406 return this._size > 0;
1407 }
1408 > } event.ts
1409 >
1410 > export interface EventDeliveryQueue {
1411 > _isEventDeliveryQueue: true;
1412 > }
1413 >
1414 > export const createEventDeliveryQueue = (): EventDeliveryQueue => new EventDeliveryQueuePrivate();
1415 >
1416 class EventDeliveryQueuePrivate implements EventDeliveryQueue {
1417 declare _isEventDeliveryQueue: true;
1426 */
1427 public end = 0;
1428 > event.ts
1429 > /**
1430 > * Emitter currently being dispatched on. Emitter._listeners is always an array.
1431 > */
1432 > public current?: Emitter<any>;
1433 > /**
1434 > * Currently emitting value. Defined whenever `current` is.
1435 > */
1436 > public value?: unknown;
1437 >
1438 > public enqueue<T>(emitter: Emitter<T>, value: T, end: number) {
1439 this.i = 0;
1440 this.end = end;
1442 this.value = value;
1443 }
1444 > event.ts
1445 > public reset() {
1446 this.i = this.end; // force any current emission loop to stop, mainly for during dispose
1447 this.current = undefined;
1448 this.value = undefined;
1449 }
1450 > } event.ts
1451 >
1452 > export interface IWaitUntil {
1453 > token: CancellationToken;
1454 > waitUntil(thenable: Promise<unknown>): void;
1455 > }
1456 >
1457 > export type IWaitUntilData<T> = Omit<Omit<T, 'waitUntil'>, 'token'>;
1458 >
1459 > export class AsyncEmitter<T extends IWaitUntil> extends Emitter<T> {
1460 >
1461 > private _asyncDeliveryQueue?: LinkedList<[(ev: T) => void, IWaitUntilData<T>]>;
1462 >
1463 > async fireAsync(data: IWaitUntilData<T>, token: CancellationToken, promiseJoin?: (p: Promise<unknown>, listener: Function) => Promise<unknown>): Promise<void> {
1464 if (!this._listeners) {
1465 return;
1512 }
1513 }
1514 > } event.ts
1515 >
1516 >
1517 > export class PauseableEmitter<T> extends Emitter<T> {
1518 >
1519 > private _isPaused = 0;
1520 > protected _eventQueue = new LinkedList<T>();
1521 > private _mergeFn?: (input: T[]) => T;
1522 >
1523 > public get isPaused(): boolean {
1524 > return this._isPaused !== 0;
1525 > }
1526 >
1527 > constructor(options?: EmitterOptions & { merge?: (input: T[]) => T }) {
1528 super(options);
1529 this._mergeFn = options?.merge;
1530 }
1531 > event.ts
1532 > pause(): void {
1533 this._isPaused++;
1534 }
1535 > event.ts
1536 > resume(): void {
1537 if (this._isPaused !== 0 && --this._isPaused === 0) {
1538 if (this._mergeFn) {
1554 }
1555 }
1556 > event.ts
1557 > override fire(event: T): void {
1558 if (this._size) {
1559 if (this._isPaused !== 0) {
1564 }
1565 }
1566 > } event.ts
1567 >
1568 > export class DebounceEmitter<T> extends PauseableEmitter<T> {
1569 >
1570 > private readonly _delay: number;
1571 > private _handle: Timeout | undefined;
1572 >
1573 > constructor(options: EmitterOptions & { merge: (input: T[]) => T; delay?: number }) {
1574 super(options);
1575 this._delay = options.delay ?? 100;
1576 }
1577 > event.ts
1578 > override fire(event: T): void {
1579 if (!this._handle) {
1580 this.pause();
1586 super.fire(event);
1587 }
1588 > } event.ts
1589 >
1590 > /**
1591 > * An emitter which queue all events and then process them at the
1592 > * end of the event loop.
1593 > */
1594 > export class MicrotaskEmitter<T> extends Emitter<T> {
1595 > private _queuedEvents: T[] = [];
1596 > private _mergeFn?: (input: T[]) => T;
1597 >
1598 > constructor(options?: EmitterOptions & { merge?: (input: T[]) => T }) {
1599 super(options);
1600 this._mergeFn = options?.merge;
1601 }
1602 > override fire(event: T): void { event.ts
1603
1604 if (!this.hasListeners()) {
1618 }
1619 }
1620 > } event.ts
1621 >
1622 > /**
1623 > * An event emitter that multiplexes many events into a single event.
1624 > *
1625 > * @example Listen to the `onData` event of all `Thing`s, dynamically adding and removing `Thing`s
1626 > * to the multiplexer as needed.
1627 > *
1628 > * ```typescript
1629 > * const anythingDataMultiplexer = new EventMultiplexer<{ data: string }>();
1630 > *
1631 > * const thingListeners = DisposableMap<Thing, IDisposable>();
1632 > *
1633 > * thingService.onDidAddThing(thing => {
1634 > * thingListeners.set(thing, anythingDataMultiplexer.add(thing.onData);
1635 > * });
1636 > * thingService.onDidRemoveThing(thing => {
1637 > * thingListeners.deleteAndDispose(thing);
1638 > * });
1639 > *
1640 > * anythingDataMultiplexer.event(e => {
1641 > * console.log('Something fired data ' + e.data)
1642 > * });
1643 > * ```
1644 > */
1645 > export class EventMultiplexer<T> implements IDisposable {
1646 >
1647 > private readonly emitter: Emitter<T>;
1648 > private hasListeners = false;
1649 > private events: { event: Event<T>; listener: IDisposable | null }[] = [];
1650 >
1651 > constructor() {
1652 this.emitter = new Emitter<T>({
1653 onWillAddFirstListener: () => this.onFirstListenerAdd(),
1655 });
1656 }
1657 > event.ts
1658 > get event(): Event<T> {
1659 return this.emitter.event;
1660 }
1661 > event.ts
1662 > add(event: Event<T>): IDisposable {
1663 const e = { event: event, listener: null };
1664 this.events.push(e);
1679 return toDisposable(createSingleCallFunction(dispose));
1680 }
1681 > event.ts
1682 > private onFirstListenerAdd(): void {
1683 this.hasListeners = true;
1684 this.events.forEach(e => this.hook(e));
1685 }
1686 > event.ts
1687 > private onLastListenerRemove(): void {
1688 this.hasListeners = false;
1689 this.events.forEach(e => this.unhook(e));
1690 }
1691 > event.ts
1692 > private hook(e: { event: Event<T>; listener: IDisposable | null }): void {
1693 e.listener = e.event(r => this.emitter.fire(r));
1694 }
1695 > event.ts
1696 > private unhook(e: { event: Event<T>; listener: IDisposable | null }): void {
1697 e.listener?.dispose();
1698 e.listener = null;
1699 }
1700 > event.ts
1701 > dispose(): void {
1702 this.emitter.dispose();
1703
1707 this.events = [];
1708 }
1709 > } event.ts
1710 >
1711 > export interface IDynamicListEventMultiplexer<TEventType> extends IDisposable {
1712 > readonly event: Event<TEventType>;
1713 > }
1714 > export class DynamicListEventMultiplexer<TItem, TEventType> implements IDynamicListEventMultiplexer<TEventType> {
1715 > private readonly _store = new DisposableStore();
1716 >
1717 > readonly event: Event<TEventType>;
1718 >
1719 > constructor(
1720 items: TItem[],
1721 onAddItem: Event<TItem>,
1747 this.event = multiplexer.event;
1748 }
1749 > event.ts
1750 > dispose() {
1751 this._store.dispose();
1752 }
1753 > } event.ts
1754 >
1755 > /**
1756 > * The EventBufferer is useful in situations in which you want
1757 > * to delay firing your events during some code.
1758 > * You can wrap that code and be sure that the event will not
1759 > * be fired during that wrap.
1760 > *
1761 > * ```
1762 > * const emitter: Emitter;
1763 > * const delayer = new EventDelayer();
1764 > * const delayedEvent = delayer.wrapEvent(emitter.event);
1765 > *
1766 > * delayedEvent(console.log);
1767 > *
1768 > * delayer.bufferEvents(() => {
1769 > * emitter.fire(); // event will not be fired yet
1770 > * });
1771 > *
1772 > * // event will only be fired at this point
1773 > * ```
1774 > */
1775 > export class EventBufferer {
1776
1777 private data: { buffers: Function[] }[] = [];
1778 > event.ts
1779 > wrapEvent<T>(event: Event<T>): Event<T>;
1780 > wrapEvent<T>(event: Event<T>, reduce: (last: T | undefined, event: T) => T): Event<T>;
1781 > wrapEvent<T, O>(event: Event<T>, reduce: (last: O | undefined, event: T) => O, initial: O): Event<O>;
1782 > wrapEvent<T, O>(event: Event<T>, reduce?: (last: T | O | undefined, event: T) => T | O, initial?: O): Event<O | T> {
1783 return (listener, thisArgs?, disposables?) => {
1784 return event(i => {
1832 };
1833 }
1834 > event.ts
1835 > bufferEvents<R = void>(fn: () => R): R {
1836 const data = { buffers: new Array<Function>() };
1837 this.data.push(data);
1841 return r;
1842 }
1843 > } event.ts
1844 >
1845 > /**
1846 > * A Relay is an event forwarder which functions as a replugabble event pipe.
1847 > * Once created, you can connect an input event to it and it will simply forward
1848 > * events from that input event through its own `event` property. The `input`
1849 > * can be changed at any point in time.
1850 > */
1851 > export class Relay<T> implements IDisposable {
1852
1853 private listening = false;
1867
1868 readonly event: Event<T> = this.emitter.event;
1869 > event.ts
1870 > set input(event: Event<T>) {
1871 this.inputEvent = event;
1872
1876 }
1877 }
1878 > event.ts
1879 > dispose() {
1880 this.inputEventListener.dispose();
1881 this.emitter.dispose();
1882 }
1883 > } event.ts
1884 >
1885 > export interface IValueWithChangeEvent<T> {
1886 > readonly onDidChange: Event<void>;
1887 > get value(): T;
1888 > }
1889 >
1890 > export class ValueWithChangeEvent<T> implements IValueWithChangeEvent<T> {
1891 > public static const<T>(value: T): IValueWithChangeEvent<T> {
1892 > return new ConstValueWithChangeEvent(value);
1893 > }
1894 >
1895 > private readonly _onDidChange = new Emitter<void>();
1896 > readonly onDidChange: Event<void> = this._onDidChange.event;
1897 >
1898 > constructor(private _value: T) { }
1899 >
1900 > get value(): T {
1901 return this._value;
1902 }
1903 > event.ts
1904 > set value(value: T) {
1905 if (value !== this._value) {
1906 this._value = value;
1908 }
1909 }
1910 > } event.ts
1911 >
1912 > class ConstValueWithChangeEvent<T> implements IValueWithChangeEvent<T> {
1913 > public readonly onDidChange: Event<void> = Event.None;
1914 >
1915 > constructor(readonly value: T) { }
1916 > }
1917 >
1918 > /**
1919 > * @param handleItem Is called for each item in the set (but only the first time the item is seen in the set).
1920 > * The returned disposable is disposed if the item is no longer in the set.
1921 > */
1922 > export function trackSetChanges<T>(getData: () => ReadonlySet<T>, onDidChangeData: Event<unknown>, handleItem: (d: T) => IDisposable): IDisposable {
1923 const map = new DisposableMap<T, IDisposable>();
1924 let oldData = new Set(getData());
1942 return store;
1943 }
1944 > event.ts
1945 >
1946 function addToDisposables(result: IDisposable, disposables: DisposableStore | IDisposable[] | undefined) {
1947 if (disposables instanceof DisposableStore) {
1951 }
1952 }
1953 > event.ts
1954 function disposeAndRemove(result: IDisposable, disposables: DisposableStore | IDisposable[] | undefined) {
1955 if (disposables instanceof DisposableStore) {
src/vs/base/common/stopwatch.ts 25 introduced LOC · 6 ranges

Open complete file

1 > /*--------------------------------------------------------------------------------------------- stopwatch.ts
2 > * Copyright (c) Microsoft Corporation. All rights reserved.
3 > * Licensed under the MIT License. See License.txt in the project root for license information.
4 > *--------------------------------------------------------------------------------------------*/
5 >
6 > declare const globalThis: { performance: { now(): number } };
7 > const performanceNow = globalThis.performance.now.bind(globalThis.performance);
8 >
9 > export class StopWatch {
10 >
11 > private _startTime: number;
12 > private _stopTime: number;
13 >
14 > private readonly _now: () => number;
15 >
16 > public static create(highResolution?: boolean): StopWatch {
17 return new StopWatch(highResolution);
18 }
20 > constructor(highResolution?: boolean) {
21 this._now = highResolution === false ? Date.now : performanceNow;
22 this._startTime = this._now();
23 this._stopTime = -1;
24 }
26 > public stop(): void {
27 this._stopTime = this._now();
28 }
30 > public reset(): void {
31 this._startTime = this._now();
32 this._stopTime = -1;
33 }
35 > public elapsed(): number {
36 if (this._stopTime !== -1) {
37 return this._stopTime - this._startTime;
39 return this._now() - this._startTime;
40 }
41 > } stopwatch.ts