75 lines
2.8 KiB
JavaScript
75 lines
2.8 KiB
JavaScript
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import { Subscriber } from '../Subscriber';
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export function refCount() {
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return function refCountOperatorFunction(source) {
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return source.lift(new RefCountOperator(source));
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};
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}
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class RefCountOperator {
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constructor(connectable) {
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this.connectable = connectable;
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}
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call(subscriber, source) {
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const { connectable } = this;
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connectable._refCount++;
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const refCounter = new RefCountSubscriber(subscriber, connectable);
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const subscription = source.subscribe(refCounter);
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if (!refCounter.closed) {
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refCounter.connection = connectable.connect();
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}
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return subscription;
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}
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}
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class RefCountSubscriber extends Subscriber {
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constructor(destination, connectable) {
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super(destination);
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this.connectable = connectable;
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}
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/** @deprecated internal use only */ _unsubscribe() {
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const { connectable } = this;
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if (!connectable) {
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this.connection = null;
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return;
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}
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this.connectable = null;
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const refCount = connectable._refCount;
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if (refCount <= 0) {
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this.connection = null;
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return;
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}
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connectable._refCount = refCount - 1;
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if (refCount > 1) {
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this.connection = null;
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return;
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}
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///
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// Compare the local RefCountSubscriber's connection Subscription to the
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// connection Subscription on the shared ConnectableObservable. In cases
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// where the ConnectableObservable source synchronously emits values, and
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// the RefCountSubscriber's downstream Observers synchronously unsubscribe,
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// execution continues to here before the RefCountOperator has a chance to
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// supply the RefCountSubscriber with the shared connection Subscription.
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// For example:
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// ```
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// Observable.range(0, 10)
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// .publish()
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// .refCount()
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// .take(5)
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// .subscribe();
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// ```
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// In order to account for this case, RefCountSubscriber should only dispose
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// the ConnectableObservable's shared connection Subscription if the
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// connection Subscription exists, *and* either:
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// a. RefCountSubscriber doesn't have a reference to the shared connection
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// Subscription yet, or,
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// b. RefCountSubscriber's connection Subscription reference is identical
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// to the shared connection Subscription
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///
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const { connection } = this;
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const sharedConnection = connectable._connection;
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this.connection = null;
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if (sharedConnection && (!connection || sharedConnection === connection)) {
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sharedConnection.unsubscribe();
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}
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}
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}
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//# sourceMappingURL=refCount.js.map
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