//
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// Debounce.swift
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// RxSwift
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//
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// Created by Krunoslav Zaher on 9/11/16.
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// Copyright © 2016 Krunoslav Zaher. All rights reserved.
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//
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import Foundation
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extension ObservableType {
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/**
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Ignores elements from an observable sequence which are followed by another element within a specified relative time duration, using the specified scheduler to run throttling timers.
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- seealso: [debounce operator on reactivex.io](http://reactivex.io/documentation/operators/debounce.html)
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- parameter dueTime: Throttling duration for each element.
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- parameter scheduler: Scheduler to run the throttle timers on.
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- returns: The throttled sequence.
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*/
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public func debounce(_ dueTime: RxTimeInterval, scheduler: SchedulerType)
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-> Observable<Element> {
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return Debounce(source: self.asObservable(), dueTime: dueTime, scheduler: scheduler)
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}
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}
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final private class DebounceSink<Observer: ObserverType>
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: Sink<Observer>
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, ObserverType
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, LockOwnerType
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, SynchronizedOnType {
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typealias Element = Observer.Element
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typealias ParentType = Debounce<Element>
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private let parent: ParentType
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let lock = RecursiveLock()
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// state
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private var id = 0 as UInt64
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private var value: Element?
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let cancellable = SerialDisposable()
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init(parent: ParentType, observer: Observer, cancel: Cancelable) {
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self.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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let subscription = self.parent.source.subscribe(self)
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return Disposables.create(subscription, cancellable)
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}
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func on(_ event: Event<Element>) {
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self.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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self.id = self.id &+ 1
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let currentId = self.id
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self.value = element
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let scheduler = self.parent.scheduler
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let dueTime = self.parent.dueTime
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let d = SingleAssignmentDisposable()
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self.cancellable.disposable = d
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d.setDisposable(scheduler.scheduleRelative(currentId, dueTime: dueTime, action: self.propagate))
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case .error:
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self.value = nil
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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 value = self.value {
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self.value = nil
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self.forwardOn(.next(value))
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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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func propagate(_ currentId: UInt64) -> Disposable {
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self.lock.performLocked {
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let originalValue = self.value
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if let value = originalValue, self.id == currentId {
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self.value = nil
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self.forwardOn(.next(value))
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}
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return Disposables.create()
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}
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}
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}
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final private class Debounce<Element>: Producer<Element> {
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fileprivate let source: Observable<Element>
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fileprivate let dueTime: RxTimeInterval
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fileprivate let scheduler: SchedulerType
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init(source: Observable<Element>, dueTime: RxTimeInterval, scheduler: SchedulerType) {
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self.source = source
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self.dueTime = dueTime
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self.scheduler = scheduler
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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 = DebounceSink(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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