RxSwift/RxTests/ColdObservable.swift

//
//  ColdObservable.swift
//  Rx
//
//  Created by Krunoslav Zaher on 3/14/15.
//  Copyright © 2015 Krunoslav Zaher. All rights reserved.
//

import RxSwift

/**
A representation of cold observable sequence.

Recorded events are replayed after subscription once per subscriber.

Event times represent relative offset to subscription time.
*/
class ColdObservable<Element>
    : TestableObservable<Element> {

    override init(testScheduler: TestScheduler, recordedEvents: [Recorded<Event<Element>>]) {
        super.init(testScheduler: testScheduler, recordedEvents: recordedEvents)
    }

    /**
    Subscribes `observer` to receive events for this sequence.
    */
    override func subscribe<O : ObserverType>(_ observer: O) -> Disposable where O.E == Element {
        subscriptions.append(Subscription(testScheduler.clock))
        
        let i = self.subscriptions.count - 1

        for recordedEvent in recordedEvents {
            _ = testScheduler.scheduleRelativeVirtual((), dueTime: recordedEvent.time, action: { (_) in
                observer.on(recordedEvent.value)
                return Disposables.create()
            })
        }
        
        return Disposables.create {
            let existing = self.subscriptions[i]
            self.subscriptions[i] = Subscription(existing.subscribe, self.testScheduler.clock)
        }
    }
}