/
Signal_Loop.swift
46 lines (38 loc) · 1.37 KB
/
Signal_Loop.swift
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import Foundation
public enum SignalFeedbackLoopState<T> {
case initial
case loop(T)
}
public func feedbackLoop<R1, R, E>(once: @escaping (SignalFeedbackLoopState<R1>) -> Signal<R1, E>?, reduce: @escaping (R1, R1) -> R1) -> Signal<R, E> {
return Signal { subscriber in
let currentDisposable = MetaDisposable()
let state = Atomic<R1?>(value: nil)
var loopAgain: (() -> Void)?
let loopOnce: (MetaDisposable?) -> Void = { disposable in
if let signal = once(.initial) {
disposable?.set(signal.start(next: { next in
let _ = state.modify { value in
if let value = value {
return reduce(value, next)
} else {
return value
}
}
}, error: { error in
subscriber.putError(error)
}, completed: {
loopAgain?()
}))
} else {
subscriber.putCompletion()
}
}
loopAgain = { [weak currentDisposable] in
loopOnce(currentDisposable)
}
loopOnce(currentDisposable)
return ActionDisposable {
currentDisposable.dispose()
}
}
}