143 lines
4.1 KiB
Swift
143 lines
4.1 KiB
Swift
//
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// Sample.swift
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// RxSwift
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//
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// Created by Krunoslav Zaher on 5/1/15.
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// Copyright © 2015 Krunoslav Zaher. All rights reserved.
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//
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extension ObservableType {
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/**
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Samples the source observable sequence using a sampler observable sequence producing sampling ticks.
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Upon each sampling tick, the latest element (if any) in the source sequence during the last sampling interval is sent to the resulting sequence.
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**In case there were no new elements between sampler ticks, no element is sent to the resulting sequence.**
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- seealso: [sample operator on reactivex.io](http://reactivex.io/documentation/operators/sample.html)
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- parameter sampler: Sampling tick sequence.
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- returns: Sampled observable sequence.
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*/
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public func sample<O: ObservableType>(_ sampler: O)
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-> Observable<E> {
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return Sample(source: self.asObservable(), sampler: sampler.asObservable())
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}
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}
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final fileprivate class SamplerSink<O: ObserverType, SampleType>
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: ObserverType
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, LockOwnerType
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, SynchronizedOnType {
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typealias E = SampleType
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typealias Parent = SampleSequenceSink<O, SampleType>
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fileprivate let _parent: Parent
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var _lock: RecursiveLock {
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return _parent._lock
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}
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init(parent: Parent) {
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_parent = parent
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}
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func on(_ event: Event<E>) {
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synchronizedOn(event)
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}
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func _synchronized_on(_ event: Event<E>) {
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switch event {
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case .next:
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if let element = _parent._element {
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_parent._element = nil
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_parent.forwardOn(.next(element))
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}
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if _parent._atEnd {
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_parent.forwardOn(.completed)
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_parent.dispose()
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}
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case .error(let e):
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_parent.forwardOn(.error(e))
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_parent.dispose()
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case .completed:
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if let element = _parent._element {
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_parent._element = nil
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_parent.forwardOn(.next(element))
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}
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if _parent._atEnd {
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_parent.forwardOn(.completed)
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_parent.dispose()
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}
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}
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}
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}
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final fileprivate class SampleSequenceSink<O: ObserverType, SampleType>
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: Sink<O>
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, ObserverType
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, LockOwnerType
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, SynchronizedOnType {
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typealias Element = O.E
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typealias Parent = Sample<Element, SampleType>
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fileprivate let _parent: Parent
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let _lock = RecursiveLock()
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// state
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fileprivate var _element = nil as Element?
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fileprivate var _atEnd = false
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fileprivate let _sourceSubscription = SingleAssignmentDisposable()
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init(parent: Parent, observer: O, cancel: Cancelable) {
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_parent = parent
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super.init(observer: observer, cancel: cancel)
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}
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func run() -> Disposable {
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_sourceSubscription.setDisposable(_parent._source.subscribe(self))
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let samplerSubscription = _parent._sampler.subscribe(SamplerSink(parent: self))
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return Disposables.create(_sourceSubscription, samplerSubscription)
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}
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func on(_ event: Event<Element>) {
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synchronizedOn(event)
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}
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func _synchronized_on(_ event: Event<Element>) {
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switch event {
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case .next(let element):
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_element = element
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case .error:
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forwardOn(event)
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dispose()
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case .completed:
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_atEnd = true
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_sourceSubscription.dispose()
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}
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}
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}
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final fileprivate class Sample<Element, SampleType> : Producer<Element> {
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fileprivate let _source: Observable<Element>
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fileprivate let _sampler: Observable<SampleType>
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init(source: Observable<Element>, sampler: Observable<SampleType>) {
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_source = source
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_sampler = sampler
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}
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override func run<O: ObserverType>(_ observer: O, cancel: Cancelable) -> (sink: Disposable, subscription: Disposable) where O.E == Element {
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let sink = SampleSequenceSink(parent: self, observer: observer, cancel: cancel)
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let subscription = sink.run()
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return (sink: sink, subscription: subscription)
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}
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}
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