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@stephencelis
stephencelis committed Jun 14, 2024
1 parent 545a092 commit 6d98d57
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60 changes: 0 additions & 60 deletions Sources/ConcurrencyExtras/AsyncStream.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -65,66 +65,6 @@ extension AsyncStream {
}
}

#if swift(<5.9)
/// Constructs and returns a stream along with its backing continuation.
///
/// A back-port of [SE-0388: Convenience Async[Throwing]Stream.makeStream methods][se-0388].
///
/// This is handy for immediately escaping the continuation from an async stream, which
/// typically requires multiple steps:
///
/// ```swift
/// var _continuation: AsyncStream<Int>.Continuation!
/// let stream = AsyncStream<Int> { continuation = $0 }
/// let continuation = _continuation!
///
/// // vs.
///
/// let (stream, continuation) = AsyncStream.makeStream(of: Int.self)
/// ```
///
/// This tool is usually used for tests where we need to supply an async sequence to a
/// dependency endpoint and get access to its continuation so that we can emulate the dependency
/// emitting data. For example, suppose you have a dependency exposing an async sequence for
/// listening to notifications. To test this you can use `makeStream`:
///
/// ```swift
/// func testScreenshots() {
/// let screenshots = AsyncStream.makeStream(of: Void.self)
///
/// let model = withDependencies {
/// $0.screenshots = { screenshots.stream }
/// } operation: {
/// FeatureModel()
/// }
///
/// XCTAssertEqual(model.screenshotCount, 0)
/// screenshots.continuation.yield() // Simulate a screenshot being taken.
/// XCTAssertEqual(model.screenshotCount, 1)
/// }
/// ```
///
/// > Warning: ⚠️ `AsyncStream` does not support multiple subscribers, therefore you can only
/// > use this helper to test features that do not subscribe multiple times to the dependency
/// > endpoint.
///
/// [se-0388]: https://github.com/apple/swift-evolution/blob/main/proposals/0388-async-stream-factory.md
///
/// - Parameters:
/// - elementType: The type of element the `AsyncStream` produces.
/// - limit: A Continuation.BufferingPolicy value to set the stream’s buffering behavior. By
/// default, the stream buffers an unlimited number of elements. You can also set the policy
/// to buffer a specified number of oldest or newest elements.
/// - Returns: An `AsyncStream`.
public static func makeStream(
of elementType: Element.Type = Element.self,
bufferingPolicy limit: Continuation.BufferingPolicy = .unbounded
) -> (stream: Self, continuation: Continuation) {
var continuation: Continuation!
return (Self(elementType, bufferingPolicy: limit) { continuation = $0 }, continuation)
}
#endif

/// An `AsyncStream` that never emits and never completes unless cancelled.
public static var never: Self {
Self { _ in }
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62 changes: 0 additions & 62 deletions Sources/ConcurrencyExtras/AsyncThrowingStream.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -18,68 +18,6 @@ extension AsyncThrowingStream where Failure == Error {
}
}

#if swift(<5.9)
/// Constructs and returns a stream along with its backing continuation.
///
/// A back-port of [SE-0388: Convenience Async[Throwing]Stream.makeStream methods][se-0388].
///
/// This is handy for immediately escaping the continuation from an async stream, which
/// typically requires multiple steps:
///
/// ```swift
/// var _continuation: AsyncThrowingStream<Int, Error>.Continuation!
/// let stream = AsyncThrowingStream<Int, Error> { continuation = $0 }
/// let continuation = _continuation!
///
/// // vs.
///
/// let (stream, continuation) = AsyncThrowingStream.makeStream(of: Int.self)
/// ```
///
/// This tool is usually used for tests where we need to supply an async sequence to a
/// dependency endpoint and get access to its continuation so that we can emulate the dependency
/// emitting data. For example, suppose you have a dependency exposing an async sequence for
/// listening to notifications. To test this you can use `makeStream`:
///
/// ```swift
/// func testScreenshots() {
/// let screenshots = AsyncThrowingStream.makeStream(of: Void.self)
///
/// let model = withDependencies {
/// $0.screenshots = { screenshots.stream }
/// } operation: {
/// FeatureModel()
/// }
///
/// XCTAssertEqual(model.screenshotCount, 0)
/// screenshots.continuation.yield() // Simulate a screenshot being taken.
/// XCTAssertEqual(model.screenshotCount, 1)
/// }
/// ```
///
/// > Warning: ⚠️ `AsyncThrowingStream` does not support multiple subscribers, therefore you can
/// > only use this helper to test features that do not subscribe multiple times to the
/// > dependency endpoint.
///
/// [se-0388]: https://github.com/apple/swift-evolution/blob/main/proposals/0388-async-stream-factory.md
///
/// - Parameters:
/// - elementType: The type of element the `AsyncThrowingStream` produces.
/// - failureType: The type of failure the `AsyncThrowingStream` throws.
/// - limit: A Continuation.BufferingPolicy value to set the stream’s buffering behavior. By
/// default, the stream buffers an unlimited number of elements. You can also set the policy
/// to buffer a specified number of oldest or newest elements.
/// - Returns: An `AsyncThrowingStream`.
public static func makeStream(
of elementType: Element.Type = Element.self,
throwing failureType: Failure.Type = Failure.self,
bufferingPolicy limit: Continuation.BufferingPolicy = .unbounded
) -> (stream: Self, continuation: Continuation) {
var continuation: Continuation!
return (Self(elementType, bufferingPolicy: limit) { continuation = $0 }, continuation)
}
#endif

/// An `AsyncThrowingStream` that never emits and never completes unless cancelled.
public static var never: Self {
Self { _ in }
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