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node_modules/rxjs/src/internal/ReplaySubject.ts

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+import { Subject } from './Subject';
+import { SchedulerLike } from './types';
+import { queue } from './scheduler/queue';
+import { Subscriber } from './Subscriber';
+import { Subscription } from './Subscription';
+import { ObserveOnSubscriber } from './operators/observeOn';
+import { ObjectUnsubscribedError } from './util/ObjectUnsubscribedError';
+import { SubjectSubscription } from './SubjectSubscription';
+/**
+ * A variant of Subject that "replays" or emits old values to new subscribers.
+ * It buffers a set number of values and will emit those values immediately to
+ * any new subscribers in addition to emitting new values to existing subscribers.
+ *
+ * @class ReplaySubject<T>
+ */
+export class ReplaySubject<T> extends Subject<T> {
+  private _events: (ReplayEvent<T> | T)[] = [];
+  private _bufferSize: number;
+  private _windowTime: number;
+  private _infiniteTimeWindow: boolean = false;
+
+  constructor(bufferSize: number = Number.POSITIVE_INFINITY,
+              windowTime: number = Number.POSITIVE_INFINITY,
+              private scheduler?: SchedulerLike) {
+    super();
+    this._bufferSize = bufferSize < 1 ? 1 : bufferSize;
+    this._windowTime = windowTime < 1 ? 1 : windowTime;
+
+    if (windowTime === Number.POSITIVE_INFINITY) {
+      this._infiniteTimeWindow = true;
+      this.next = this.nextInfiniteTimeWindow;
+    } else {
+      this.next = this.nextTimeWindow;
+    }
+  }
+
+  private nextInfiniteTimeWindow(value: T): void {
+    const _events = this._events;
+    _events.push(value);
+    // Since this method is invoked in every next() call than the buffer
+    // can overgrow the max size only by one item
+    if (_events.length > this._bufferSize) {
+      _events.shift();
+    }
+
+    super.next(value);
+  }
+
+  private nextTimeWindow(value: T): void {
+    this._events.push(new ReplayEvent(this._getNow(), value));
+    this._trimBufferThenGetEvents();
+
+    super.next(value);
+  }
+
+  /** @deprecated This is an internal implementation detail, do not use. */
+  _subscribe(subscriber: Subscriber<T>): Subscription {
+    // When `_infiniteTimeWindow === true` then the buffer is already trimmed
+    const _infiniteTimeWindow = this._infiniteTimeWindow;
+    const _events = _infiniteTimeWindow ? this._events : this._trimBufferThenGetEvents();
+    const scheduler = this.scheduler;
+    const len = _events.length;
+    let subscription: Subscription;
+
+    if (this.closed) {
+      throw new ObjectUnsubscribedError();
+    } else if (this.isStopped || this.hasError) {
+      subscription = Subscription.EMPTY;
+    } else {
+      this.observers.push(subscriber);
+      subscription = new SubjectSubscription(this, subscriber);
+    }
+
+    if (scheduler) {
+      subscriber.add(subscriber = new ObserveOnSubscriber<T>(subscriber, scheduler));
+    }
+
+    if (_infiniteTimeWindow) {
+      for (let i = 0; i < len && !subscriber.closed; i++) {
+        subscriber.next(<T>_events[i]);
+      }
+    } else {
+      for (let i = 0; i < len && !subscriber.closed; i++) {
+        subscriber.next((<ReplayEvent<T>>_events[i]).value);
+      }
+    }
+
+    if (this.hasError) {
+      subscriber.error(this.thrownError);
+    } else if (this.isStopped) {
+      subscriber.complete();
+    }
+
+    return subscription;
+  }
+
+  _getNow(): number {
+    return (this.scheduler || queue).now();
+  }
+
+  private _trimBufferThenGetEvents(): ReplayEvent<T>[] {
+    const now = this._getNow();
+    const _bufferSize = this._bufferSize;
+    const _windowTime = this._windowTime;
+    const _events = <ReplayEvent<T>[]>this._events;
+
+    const eventsCount = _events.length;
+    let spliceCount = 0;
+
+    // Trim events that fall out of the time window.
+    // Start at the front of the list. Break early once
+    // we encounter an event that falls within the window.
+    while (spliceCount < eventsCount) {
+      if ((now - _events[spliceCount].time) < _windowTime) {
+        break;
+      }
+      spliceCount++;
+    }
+
+    if (eventsCount > _bufferSize) {
+      spliceCount = Math.max(spliceCount, eventsCount - _bufferSize);
+    }
+
+    if (spliceCount > 0) {
+      _events.splice(0, spliceCount);
+    }
+
+    return _events;
+  }
+
+}
+
+class ReplayEvent<T> {
+  constructor(public time: number, public value: T) {
+  }
+}