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Rename the producer cores. Code formatting improvements.
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@andersio
andersio committed Aug 15, 2017
1 parent 56131fc commit 798cc2d
Showing 1 changed file with 54 additions and 49 deletions.
103 changes: 54 additions & 49 deletions Sources/SignalProducer.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ public struct SignalProducer<Value, Error: Swift.Error> {
/// of:
///
/// 1. handling the single-observer `start`; and
/// 2. building `Signal`s on demand via its `make()` method, which produces a
/// 2. building `Signal`s on demand via its `makeInstance()` method, which produces a
/// `Signal` with the associated side effect and interrupt handle.
fileprivate let core: SignalProducerCore<Value, Error>

Expand Down Expand Up @@ -69,7 +69,7 @@ public struct SignalProducer<Value, Error: Swift.Error> {
let observerDidSetup = { startHandler(observer, Lifetime(disposable)) }
let interruptHandle = AnyDisposable(observer.sendInterrupted)

return SignalProducerCore.ProducedSignalReceipt(signal: signal,
return SignalProducerCore.Instance(signal: signal,
observerDidSetup: observerDidSetup,
interruptHandle: interruptHandle)
})
Expand All @@ -90,7 +90,7 @@ public struct SignalProducer<Value, Error: Swift.Error> {
/// - value: A value that should be sent by the `Signal` in a `value`
/// event.
public init(value: Value) {
self.init(EventGeneratingCore { observer, _ in
self.init(GeneratorCore { observer, _ in
observer.send(value: value)
observer.sendCompleted()
})
Expand All @@ -107,7 +107,7 @@ public struct SignalProducer<Value, Error: Swift.Error> {
/// - action: A action that yields a value to be sent by the `Signal` as
/// a `value` event.
public init(_ action: @escaping () -> Value) {
self.init(EventGeneratingCore { observer, _ in
self.init(GeneratorCore { observer, _ in
observer.send(value: action())
observer.sendCompleted()
})
Expand All @@ -123,7 +123,7 @@ public struct SignalProducer<Value, Error: Swift.Error> {
/// - parameters:
/// - action: A closure that returns instance of `Result`.
public init(_ action: @escaping () -> Result<Value, Error>) {
self.init(EventGeneratingCore { observer, _ in
self.init(GeneratorCore { observer, _ in
switch action() {
case let .success(value):
observer.send(value: value)
Expand All @@ -141,7 +141,7 @@ public struct SignalProducer<Value, Error: Swift.Error> {
/// - error: An error that should be sent by the `Signal` in a `failed`
/// event.
public init(error: Error) {
self.init(EventGeneratingCore { observer, _ in observer.send(error: error) })
self.init(GeneratorCore { observer, _ in observer.send(error: error) })
}

/// Creates a producer for a Signal that will immediately send one value
Expand All @@ -168,7 +168,7 @@ public struct SignalProducer<Value, Error: Swift.Error> {
/// - values: A sequence of values that a `Signal` will send as separate
/// `value` events and then complete.
public init<S: Sequence>(_ values: S) where S.Iterator.Element == Value {
self.init(EventGeneratingCore(isDisposable: true) { observer, disposable in
self.init(GeneratorCore(isDisposable: true) { observer, disposable in
for value in values {
observer.send(value: value)

Expand All @@ -195,7 +195,7 @@ public struct SignalProducer<Value, Error: Swift.Error> {
/// A producer for a Signal that will immediately complete without sending
/// any values.
public static var empty: SignalProducer {
return SignalProducer(EventGeneratingCore { observer, _ in observer.sendCompleted() })
return SignalProducer(GeneratorCore { observer, _ in observer.sendCompleted() })
}

/// A producer for a Signal that never sends any events to its observers.
Expand All @@ -213,7 +213,7 @@ public struct SignalProducer<Value, Error: Swift.Error> {
/// `Signal` commences. Both the produced `Signal` and an interrupt handle
/// of the signal would be passed to the closure.
public func startWithSignal(_ setup: (_ signal: Signal<Value, Error>, _ interruptHandle: Disposable) -> Void) {
let receipt = core.make()
let receipt = core.makeInstance()
setup(receipt.signal, receipt.interruptHandle)
guard !receipt.interruptHandle.isDisposed else { return }
receipt.observerDidSetup()
Expand All @@ -226,20 +226,20 @@ public struct SignalProducer<Value, Error: Swift.Error> {
/// instances of `Signal`s, the abstraction enables room of optimization for common
/// compositional and single-observer use cases.
internal class SignalProducerCore<Value, Error: Swift.Error> {
/// `ProducedSignalReceipt` represents an instance of `Signal` created from a
/// `Instance` represents an instance of `Signal` created from a
/// `SignalProducer`. In addition to the `Signal` itself, it includes also the
/// starting side effect and an interrupt handle for this particular instance.
///
/// It is the responsibility of the `ProducedSignalReceipt` consumer to ensure the
/// It is the responsibility of the `Instance` consumer to ensure the
/// starting side effect is invoked exactly once, and is invoked after observations
/// has properly setup.
struct ProducedSignalReceipt {
struct Instance {
let signal: Signal<Value, Error>
let observerDidSetup: () -> Void
let interruptHandle: Disposable
}

func make() -> ProducedSignalReceipt {
func makeInstance() -> Instance {
fatalError()
}

Expand All @@ -258,30 +258,30 @@ internal class SignalProducerCore<Value, Error: Swift.Error> {
///
/// - returns: A producer that forwards events yielded by the action.
internal func flatMapEvent<U, E>(_ transform: @escaping (@escaping Signal<U, E>.Observer.Action) -> (Signal<Value, Error>.Event) -> Void) -> SignalProducer<U, E> {
return SignalProducer<U, E>(EventTransformingCore(source: self, transform: transform))
return SignalProducer<U, E>(TransformerCore(source: self, transform: transform))
}
}

private final class SignalCore<Value, Error: Swift.Error>: SignalProducerCore<Value, Error> {
private let _make: () -> ProducedSignalReceipt
private let _make: () -> Instance

init(_ action: @escaping () -> ProducedSignalReceipt) {
init(_ action: @escaping () -> Instance) {
self._make = action
}

override func start(_ observer: Signal<Value, Error>.Observer) -> Disposable {
let instance = make()
let instance = makeInstance()
instance.signal.observe(observer)
instance.observerDidSetup()
return instance.interruptHandle
}

override func make() -> ProducedSignalReceipt {
override func makeInstance() -> Instance {
return _make()
}
}

/// `EventTransformingCore` composes event transforms, and is intended to back synchronous
/// `TransformerCore` composes event transforms, and is intended to back synchronous
/// `SignalProducer` operators in general via the core-level operator `Core.flatMapEvent`.
///
/// It takes advantage of the deferred, single-observer nature of SignalProducer. For
Expand All @@ -295,11 +295,11 @@ private final class SignalCore<Value, Error: Swift.Error>: SignalProducerCore<Va
/// chain of streams, each with a _single and persistent_ observer to its upstream. The
/// multicasting & detaching capabilities of Signal is useless in these scenarios.
///
/// So EventTransformingCore builds on top of this very fact, and composes directly at the
/// So TransformerCore builds on top of this very fact, and composes directly at the
/// level of event transforms, without any `Signal` in between.
///
/// - note: This core does not use Signal unless it is requested via `make()`.
private final class EventTransformingCore<Value, Error: Swift.Error, SourceValue, SourceError: Swift.Error>: SignalProducerCore<Value, Error> {
/// - note: This core does not use `Signal` unless it is requested via `makeInstance()`.
private final class TransformerCore<Value, Error: Swift.Error, SourceValue, SourceError: Swift.Error>: SignalProducerCore<Value, Error> {
private let source: SignalProducerCore<SourceValue, SourceError>
private let transform: (@escaping Signal<Value, Error>.Observer.Action) -> (Signal<SourceValue, SourceError>.Event) -> Void

Expand All @@ -313,30 +313,32 @@ private final class EventTransformingCore<Value, Error: Swift.Error, SourceValue
}

internal override func flatMapEvent<U, E>(_ transform: @escaping (@escaping Signal<U, E>.Observer.Action) -> (Signal<Value, Error>.Event) -> Void) -> SignalProducer<U, E> {
return SignalProducer<U, E>(EventTransformingCore<U, E, SourceValue, SourceError>(source: source) { [innerTransform = self.transform] action in
return SignalProducer<U, E>(TransformerCore<U, E, SourceValue, SourceError>(source: source) { [innerTransform = self.transform] action in
return innerTransform(transform(action))
})
}

internal override func make() -> ProducedSignalReceipt {
let product = source.make()
internal override func makeInstance() -> Instance {
let product = source.makeInstance()
let signal = Signal<Value, Error> { observer in
return product.signal.observe(.init(observer, transform))
}

return ProducedSignalReceipt(signal: signal,
return Instance(signal: signal,
observerDidSetup: product.observerDidSetup,
interruptHandle: product.interruptHandle)
}
}

/// `EventGeneratingCore` wraps a generator closure that would be invoked upon a produced
/// `GeneratorCore` wraps a generator closure that would be invoked upon a produced
/// `Signal` when started. The generator closure is passed only the input observer and the
/// cancel disposable.
///
/// It is intended for constant `SignalProducers`s that synchronously emits all events
/// without escaping the `Observer`.
private final class EventGeneratingCore<Value, Error: Swift.Error>: SignalProducerCore<Value, Error> {
///
/// - note: This core does not use `Signal` unless it is requested via `makeInstance()`.
private final class GeneratorCore<Value, Error: Swift.Error>: SignalProducerCore<Value, Error> {
private let isDisposable: Bool
private let generator: (Signal<Value, Error>.Observer, Disposable) -> Void

Expand All @@ -353,11 +355,11 @@ private final class EventGeneratingCore<Value, Error: Swift.Error>: SignalProduc
return d
}

internal override func make() -> ProducedSignalReceipt {
internal override func makeInstance() -> Instance {
let (signal, observer) = Signal<Value, Error>.pipe()
let d = AnyDisposable(observer.sendInterrupted)

return ProducedSignalReceipt(signal: signal,
return Instance(signal: signal,
observerDidSetup: { self.generator(observer, d) },
interruptHandle: d)
}
Expand All @@ -371,7 +373,7 @@ extension SignalProducer where Error == NoError {
/// - value: A value that should be sent by the `Signal` in a `value`
/// event.
public init(value: Value) {
self.init(EventGeneratingCore { observer, _ in
self.init(GeneratorCore { observer, _ in
observer.send(value: value)
observer.sendCompleted()
})
Expand All @@ -384,7 +386,7 @@ extension SignalProducer where Error == NoError {
/// - values: A sequence of values that a `Signal` will send as separate
/// `value` events and then complete.
public init<S: Sequence>(_ values: S) where S.Iterator.Element == Value {
self.init(EventGeneratingCore(isDisposable: true) { observer, disposable in
self.init(GeneratorCore(isDisposable: true) { observer, disposable in
for value in values {
observer.send(value: value)

Expand Down Expand Up @@ -594,30 +596,33 @@ extension SignalProducer {
return SignalProducer<U, F>(SignalCore {
// Transform the `Signal`, and pass through the `didCreate` side effect and
// the interruptHandle.
let receipt = self.core.make()
let receipt = self.core.makeInstance()
return .init(signal: transform(receipt.signal),
observerDidSetup: receipt.observerDidSetup,
interruptHandle: receipt.interruptHandle)
})
})
}

private func lift<U, F, V, G>(leftFirst: Bool, _ transform: @escaping (Signal<Value, Error>) -> (Signal<U, F>) -> Signal<V, G>) -> (SignalProducer<U, F>) -> SignalProducer<V, G> {
return { otherProducer in
return SignalProducer<V, G>(SignalCore {
let left = self.core.make()
let right = otherProducer.core.make()

return .init(signal: transform(left.signal)(right.signal),
observerDidSetup: {
if leftFirst {
left.observerDidSetup()
right.observerDidSetup()
} else {
right.observerDidSetup()
left.observerDidSetup()
}},
interruptHandle: CompositeDisposable([left.interruptHandle, right.interruptHandle]))
})
let left = self.core.makeInstance()
let right = otherProducer.core.makeInstance()

return .init(
signal: transform(left.signal)(right.signal),
observerDidSetup: {
if leftFirst {
left.observerDidSetup()
right.observerDidSetup()
} else {
right.observerDidSetup()
left.observerDidSetup()
}
},
interruptHandle: CompositeDisposable([left.interruptHandle, right.interruptHandle])
)
})
}
}

Expand Down Expand Up @@ -1684,7 +1689,7 @@ extension SignalProducer {
value: ((Value) -> Void)? = nil
) -> SignalProducer<Value, Error> {
return SignalProducer(SignalCore {
let instance = self.core.make()
let instance = self.core.makeInstance()
let signal = instance.signal.on(event: event,
failed: failed,
completed: completed,
Expand Down

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