//
|
// Take.swift
|
// RxSwift
|
//
|
// Created by Krunoslav Zaher on 6/12/15.
|
// Copyright © 2015 Krunoslav Zaher. All rights reserved.
|
//
|
|
extension ObservableType {
|
|
/**
|
Returns a specified number of contiguous elements from the start of an observable sequence.
|
|
- seealso: [take operator on reactivex.io](http://reactivex.io/documentation/operators/take.html)
|
|
- parameter count: The number of elements to return.
|
- returns: An observable sequence that contains the specified number of elements from the start of the input sequence.
|
*/
|
public func take(_ count: Int)
|
-> Observable<Element> {
|
if count == 0 {
|
return Observable.empty()
|
}
|
else {
|
return TakeCount(source: self.asObservable(), count: count)
|
}
|
}
|
}
|
|
extension ObservableType {
|
|
/**
|
Takes elements for the specified duration from the start of the observable source sequence, using the specified scheduler to run timers.
|
|
- seealso: [take operator on reactivex.io](http://reactivex.io/documentation/operators/take.html)
|
|
- parameter duration: Duration for taking elements from the start of the sequence.
|
- parameter scheduler: Scheduler to run the timer on.
|
- returns: An observable sequence with the elements taken during the specified duration from the start of the source sequence.
|
*/
|
public func take(_ duration: RxTimeInterval, scheduler: SchedulerType)
|
-> Observable<Element> {
|
return TakeTime(source: self.asObservable(), duration: duration, scheduler: scheduler)
|
}
|
}
|
|
// count version
|
|
final private class TakeCountSink<Observer: ObserverType>: Sink<Observer>, ObserverType {
|
typealias Element = Observer.Element
|
typealias Parent = TakeCount<Element>
|
|
private let _parent: Parent
|
|
private var _remaining: Int
|
|
init(parent: Parent, observer: Observer, cancel: Cancelable) {
|
self._parent = parent
|
self._remaining = parent._count
|
super.init(observer: observer, cancel: cancel)
|
}
|
|
func on(_ event: Event<Element>) {
|
switch event {
|
case .next(let value):
|
|
if self._remaining > 0 {
|
self._remaining -= 1
|
|
self.forwardOn(.next(value))
|
|
if self._remaining == 0 {
|
self.forwardOn(.completed)
|
self.dispose()
|
}
|
}
|
case .error:
|
self.forwardOn(event)
|
self.dispose()
|
case .completed:
|
self.forwardOn(event)
|
self.dispose()
|
}
|
}
|
|
}
|
|
final private class TakeCount<Element>: Producer<Element> {
|
private let _source: Observable<Element>
|
fileprivate let _count: Int
|
|
init(source: Observable<Element>, count: Int) {
|
if count < 0 {
|
rxFatalError("count can't be negative")
|
}
|
self._source = source
|
self._count = count
|
}
|
|
override func run<Observer: ObserverType>(_ observer: Observer, cancel: Cancelable) -> (sink: Disposable, subscription: Disposable) where Observer.Element == Element {
|
let sink = TakeCountSink(parent: self, observer: observer, cancel: cancel)
|
let subscription = self._source.subscribe(sink)
|
return (sink: sink, subscription: subscription)
|
}
|
}
|
|
// time version
|
|
final private class TakeTimeSink<Element, Observer: ObserverType>
|
: Sink<Observer>
|
, LockOwnerType
|
, ObserverType
|
, SynchronizedOnType where Observer.Element == Element {
|
typealias Parent = TakeTime<Element>
|
|
private let _parent: Parent
|
|
let _lock = RecursiveLock()
|
|
init(parent: Parent, observer: Observer, cancel: Cancelable) {
|
self._parent = parent
|
super.init(observer: observer, cancel: cancel)
|
}
|
|
func on(_ event: Event<Element>) {
|
self.synchronizedOn(event)
|
}
|
|
func _synchronized_on(_ event: Event<Element>) {
|
switch event {
|
case .next(let value):
|
self.forwardOn(.next(value))
|
case .error:
|
self.forwardOn(event)
|
self.dispose()
|
case .completed:
|
self.forwardOn(event)
|
self.dispose()
|
}
|
}
|
|
func tick() {
|
self._lock.lock(); defer { self._lock.unlock() }
|
|
self.forwardOn(.completed)
|
self.dispose()
|
}
|
|
func run() -> Disposable {
|
let disposeTimer = self._parent._scheduler.scheduleRelative((), dueTime: self._parent._duration) { _ in
|
self.tick()
|
return Disposables.create()
|
}
|
|
let disposeSubscription = self._parent._source.subscribe(self)
|
|
return Disposables.create(disposeTimer, disposeSubscription)
|
}
|
}
|
|
final private class TakeTime<Element>: Producer<Element> {
|
typealias TimeInterval = RxTimeInterval
|
|
fileprivate let _source: Observable<Element>
|
fileprivate let _duration: TimeInterval
|
fileprivate let _scheduler: SchedulerType
|
|
init(source: Observable<Element>, duration: TimeInterval, scheduler: SchedulerType) {
|
self._source = source
|
self._scheduler = scheduler
|
self._duration = duration
|
}
|
|
override func run<Observer: ObserverType>(_ observer: Observer, cancel: Cancelable) -> (sink: Disposable, subscription: Disposable) where Observer.Element == Element {
|
let sink = TakeTimeSink(parent: self, observer: observer, cancel: cancel)
|
let subscription = sink.run()
|
return (sink: sink, subscription: subscription)
|
}
|
}
|
