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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift open source project
//
// Copyright (c) 2025 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
package struct TimeoutError: Error {
package var description: String?
}
package func withTimeout<T: Sendable>(
timeout: Duration,
description: String? = nil,
block: sending () async throws -> T
) async throws -> T {
try await withoutActuallyEscaping(block) { escapingClosure in
// This lets block be captured in the Sendable function x.
// since x is Sendable, we can smuggle it through.
nonisolated(unsafe) let b = escapingClosure
let x: @Sendable () async throws -> T = {
try await b()
}
return try await withThrowingTaskGroup(of: T.self) { group in
group.addTask {
try await x()
}
group.addTask {
try await Task.sleep(for: timeout)
throw TimeoutError(description: description)
}
let result = await group.nextResult()
group.cancelAll()
switch result {
case .failure(let error):
throw error
case .none:
throw TimeoutError(description: description)
case .success(let value):
return value
}
}
}
}
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