source: trip-planner-front/node_modules/rxjs/src/internal/ReplaySubject.ts@ 6a3a178

Last change on this file since 6a3a178 was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

initial commit

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1import { Subject } from './Subject';
2import { SchedulerLike } from './types';
3import { queue } from './scheduler/queue';
4import { Subscriber } from './Subscriber';
5import { Subscription } from './Subscription';
6import { ObserveOnSubscriber } from './operators/observeOn';
7import { ObjectUnsubscribedError } from './util/ObjectUnsubscribedError';
8import { SubjectSubscription } from './SubjectSubscription';
9/**
10 * A variant of Subject that "replays" or emits old values to new subscribers.
11 * It buffers a set number of values and will emit those values immediately to
12 * any new subscribers in addition to emitting new values to existing subscribers.
13 *
14 * @class ReplaySubject<T>
15 */
16export class ReplaySubject<T> extends Subject<T> {
17 private _events: (ReplayEvent<T> | T)[] = [];
18 private _bufferSize: number;
19 private _windowTime: number;
20 private _infiniteTimeWindow: boolean = false;
21
22 constructor(bufferSize: number = Number.POSITIVE_INFINITY,
23 windowTime: number = Number.POSITIVE_INFINITY,
24 private scheduler?: SchedulerLike) {
25 super();
26 this._bufferSize = bufferSize < 1 ? 1 : bufferSize;
27 this._windowTime = windowTime < 1 ? 1 : windowTime;
28
29 if (windowTime === Number.POSITIVE_INFINITY) {
30 this._infiniteTimeWindow = true;
31 this.next = this.nextInfiniteTimeWindow;
32 } else {
33 this.next = this.nextTimeWindow;
34 }
35 }
36
37 private nextInfiniteTimeWindow(value: T): void {
38 if (!this.isStopped) {
39 const _events = this._events;
40 _events.push(value);
41 // Since this method is invoked in every next() call than the buffer
42 // can overgrow the max size only by one item
43 if (_events.length > this._bufferSize) {
44 _events.shift();
45 }
46 }
47 super.next(value);
48 }
49
50 private nextTimeWindow(value: T): void {
51 if (!this.isStopped) {
52 this._events.push(new ReplayEvent(this._getNow(), value));
53 this._trimBufferThenGetEvents();
54 }
55 super.next(value);
56 }
57
58 /** @deprecated This is an internal implementation detail, do not use. */
59 _subscribe(subscriber: Subscriber<T>): Subscription {
60 // When `_infiniteTimeWindow === true` then the buffer is already trimmed
61 const _infiniteTimeWindow = this._infiniteTimeWindow;
62 const _events = _infiniteTimeWindow ? this._events : this._trimBufferThenGetEvents();
63 const scheduler = this.scheduler;
64 const len = _events.length;
65 let subscription: Subscription;
66
67 if (this.closed) {
68 throw new ObjectUnsubscribedError();
69 } else if (this.isStopped || this.hasError) {
70 subscription = Subscription.EMPTY;
71 } else {
72 this.observers.push(subscriber);
73 subscription = new SubjectSubscription(this, subscriber);
74 }
75
76 if (scheduler) {
77 subscriber.add(subscriber = new ObserveOnSubscriber<T>(subscriber, scheduler));
78 }
79
80 if (_infiniteTimeWindow) {
81 for (let i = 0; i < len && !subscriber.closed; i++) {
82 subscriber.next(<T>_events[i]);
83 }
84 } else {
85 for (let i = 0; i < len && !subscriber.closed; i++) {
86 subscriber.next((<ReplayEvent<T>>_events[i]).value);
87 }
88 }
89
90 if (this.hasError) {
91 subscriber.error(this.thrownError);
92 } else if (this.isStopped) {
93 subscriber.complete();
94 }
95
96 return subscription;
97 }
98
99 _getNow(): number {
100 return (this.scheduler || queue).now();
101 }
102
103 private _trimBufferThenGetEvents(): ReplayEvent<T>[] {
104 const now = this._getNow();
105 const _bufferSize = this._bufferSize;
106 const _windowTime = this._windowTime;
107 const _events = <ReplayEvent<T>[]>this._events;
108
109 const eventsCount = _events.length;
110 let spliceCount = 0;
111
112 // Trim events that fall out of the time window.
113 // Start at the front of the list. Break early once
114 // we encounter an event that falls within the window.
115 while (spliceCount < eventsCount) {
116 if ((now - _events[spliceCount].time) < _windowTime) {
117 break;
118 }
119 spliceCount++;
120 }
121
122 if (eventsCount > _bufferSize) {
123 spliceCount = Math.max(spliceCount, eventsCount - _bufferSize);
124 }
125
126 if (spliceCount > 0) {
127 _events.splice(0, spliceCount);
128 }
129
130 return _events;
131 }
132
133}
134
135class ReplayEvent<T> {
136 constructor(public time: number, public value: T) {
137 }
138}
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