//
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// AsMaybe.swift
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// RxSwift
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//
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// Created by Krunoslav Zaher on 3/12/17.
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// Copyright © 2017 Krunoslav Zaher. All rights reserved.
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//
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private final class AsMaybeSink<Observer: ObserverType> : Sink<Observer>, ObserverType {
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typealias Element = Observer.Element
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private var element: Event<Element>?
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func on(_ event: Event<Element>) {
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switch event {
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case .next:
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if self.element != nil {
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self.forwardOn(.error(RxError.moreThanOneElement))
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self.dispose()
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}
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self.element = event
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case .error:
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self.forwardOn(event)
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self.dispose()
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case .completed:
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if let element = self.element {
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self.forwardOn(element)
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}
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self.forwardOn(.completed)
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self.dispose()
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}
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}
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}
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final class AsMaybe<Element>: Producer<Element> {
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private let source: Observable<Element>
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init(source: Observable<Element>) {
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self.source = source
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}
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override func run<Observer: ObserverType>(_ observer: Observer, cancel: Cancelable) -> (sink: Disposable, subscription: Disposable) where Observer.Element == Element {
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let sink = AsMaybeSink(observer: observer, cancel: cancel)
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let subscription = self.source.subscribe(sink)
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return (sink: sink, subscription: subscription)
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}
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}
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