//
|
// RetryWhen.swift
|
// RxSwift
|
//
|
// Created by Junior B. on 06/10/15.
|
// Copyright © 2015 Krunoslav Zaher. All rights reserved.
|
//
|
|
extension ObservableType {
|
|
/**
|
Repeats the source observable sequence on error when the notifier emits a next value.
|
If the source observable errors and the notifier completes, it will complete the source sequence.
|
|
- seealso: [retry operator on reactivex.io](http://reactivex.io/documentation/operators/retry.html)
|
|
- parameter notificationHandler: A handler that is passed an observable sequence of errors raised by the source observable and returns and observable that either continues, completes or errors. This behavior is then applied to the source observable.
|
- returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
|
*/
|
public func retryWhen<TriggerObservable: ObservableType, Error: Swift.Error>(_ notificationHandler: @escaping (Observable<Error>) -> TriggerObservable)
|
-> Observable<Element> {
|
return RetryWhenSequence(sources: InfiniteSequence(repeatedValue: self.asObservable()), notificationHandler: notificationHandler)
|
}
|
|
/**
|
Repeats the source observable sequence on error when the notifier emits a next value.
|
If the source observable errors and the notifier completes, it will complete the source sequence.
|
|
- seealso: [retry operator on reactivex.io](http://reactivex.io/documentation/operators/retry.html)
|
|
- parameter notificationHandler: A handler that is passed an observable sequence of errors raised by the source observable and returns and observable that either continues, completes or errors. This behavior is then applied to the source observable.
|
- returns: An observable sequence producing the elements of the given sequence repeatedly until it terminates successfully or is notified to error or complete.
|
*/
|
public func retryWhen<TriggerObservable: ObservableType>(_ notificationHandler: @escaping (Observable<Swift.Error>) -> TriggerObservable)
|
-> Observable<Element> {
|
return RetryWhenSequence(sources: InfiniteSequence(repeatedValue: self.asObservable()), notificationHandler: notificationHandler)
|
}
|
}
|
|
final private class RetryTriggerSink<Sequence: Swift.Sequence, Observer: ObserverType, TriggerObservable: ObservableType, Error>
|
: ObserverType where Sequence.Element: ObservableType, Sequence.Element.Element == Observer.Element {
|
typealias Element = TriggerObservable.Element
|
|
typealias Parent = RetryWhenSequenceSinkIter<Sequence, Observer, TriggerObservable, Error>
|
|
private let _parent: Parent
|
|
init(parent: Parent) {
|
self._parent = parent
|
}
|
|
func on(_ event: Event<Element>) {
|
switch event {
|
case .next:
|
self._parent._parent._lastError = nil
|
self._parent._parent.schedule(.moveNext)
|
case .error(let e):
|
self._parent._parent.forwardOn(.error(e))
|
self._parent._parent.dispose()
|
case .completed:
|
self._parent._parent.forwardOn(.completed)
|
self._parent._parent.dispose()
|
}
|
}
|
}
|
|
final private class RetryWhenSequenceSinkIter<Sequence: Swift.Sequence, Observer: ObserverType, TriggerObservable: ObservableType, Error>
|
: ObserverType
|
, Disposable where Sequence.Element: ObservableType, Sequence.Element.Element == Observer.Element {
|
typealias Element = Observer.Element
|
typealias Parent = RetryWhenSequenceSink<Sequence, Observer, TriggerObservable, Error>
|
|
fileprivate let _parent: Parent
|
private let _errorHandlerSubscription = SingleAssignmentDisposable()
|
private let _subscription: Disposable
|
|
init(parent: Parent, subscription: Disposable) {
|
self._parent = parent
|
self._subscription = subscription
|
}
|
|
func on(_ event: Event<Element>) {
|
switch event {
|
case .next:
|
self._parent.forwardOn(event)
|
case .error(let error):
|
self._parent._lastError = error
|
|
if let failedWith = error as? Error {
|
// dispose current subscription
|
self._subscription.dispose()
|
|
let errorHandlerSubscription = self._parent._notifier.subscribe(RetryTriggerSink(parent: self))
|
self._errorHandlerSubscription.setDisposable(errorHandlerSubscription)
|
self._parent._errorSubject.on(.next(failedWith))
|
}
|
else {
|
self._parent.forwardOn(.error(error))
|
self._parent.dispose()
|
}
|
case .completed:
|
self._parent.forwardOn(event)
|
self._parent.dispose()
|
}
|
}
|
|
final func dispose() {
|
self._subscription.dispose()
|
self._errorHandlerSubscription.dispose()
|
}
|
}
|
|
final private class RetryWhenSequenceSink<Sequence: Swift.Sequence, Observer: ObserverType, TriggerObservable: ObservableType, Error>
|
: TailRecursiveSink<Sequence, Observer> where Sequence.Element: ObservableType, Sequence.Element.Element == Observer.Element {
|
typealias Element = Observer.Element
|
typealias Parent = RetryWhenSequence<Sequence, TriggerObservable, Error>
|
|
let _lock = RecursiveLock()
|
|
private let _parent: Parent
|
|
fileprivate var _lastError: Swift.Error?
|
fileprivate let _errorSubject = PublishSubject<Error>()
|
private let _handler: Observable<TriggerObservable.Element>
|
fileprivate let _notifier = PublishSubject<TriggerObservable.Element>()
|
|
init(parent: Parent, observer: Observer, cancel: Cancelable) {
|
self._parent = parent
|
self._handler = parent._notificationHandler(self._errorSubject).asObservable()
|
super.init(observer: observer, cancel: cancel)
|
}
|
|
override func done() {
|
if let lastError = self._lastError {
|
self.forwardOn(.error(lastError))
|
self._lastError = nil
|
}
|
else {
|
self.forwardOn(.completed)
|
}
|
|
self.dispose()
|
}
|
|
override func extract(_ observable: Observable<Element>) -> SequenceGenerator? {
|
// It is important to always return `nil` here because there are sideffects in the `run` method
|
// that are dependant on particular `retryWhen` operator so single operator stack can't be reused in this
|
// case.
|
return nil
|
}
|
|
override func subscribeToNext(_ source: Observable<Element>) -> Disposable {
|
let subscription = SingleAssignmentDisposable()
|
let iter = RetryWhenSequenceSinkIter(parent: self, subscription: subscription)
|
subscription.setDisposable(source.subscribe(iter))
|
return iter
|
}
|
|
override func run(_ sources: SequenceGenerator) -> Disposable {
|
let triggerSubscription = self._handler.subscribe(self._notifier.asObserver())
|
let superSubscription = super.run(sources)
|
return Disposables.create(superSubscription, triggerSubscription)
|
}
|
}
|
|
final private class RetryWhenSequence<Sequence: Swift.Sequence, TriggerObservable: ObservableType, Error>: Producer<Sequence.Element.Element> where Sequence.Element: ObservableType {
|
typealias Element = Sequence.Element.Element
|
|
private let _sources: Sequence
|
fileprivate let _notificationHandler: (Observable<Error>) -> TriggerObservable
|
|
init(sources: Sequence, notificationHandler: @escaping (Observable<Error>) -> TriggerObservable) {
|
self._sources = sources
|
self._notificationHandler = notificationHandler
|
}
|
|
override func run<Observer: ObserverType>(_ observer: Observer, cancel: Cancelable) -> (sink: Disposable, subscription: Disposable) where Observer.Element == Element {
|
let sink = RetryWhenSequenceSink<Sequence, Observer, TriggerObservable, Error>(parent: self, observer: observer, cancel: cancel)
|
let subscription = sink.run((self._sources.makeIterator(), nil))
|
return (sink: sink, subscription: subscription)
|
}
|
}
|
