Task+SleepIndefinitley

Author: swhitty

Sources/Task+SleepIndefinitely.swift

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+//
+//  Task+SleepIndefinitely.swift
+//  swift-timeout
+//
+//  Created by Simon Whitty on 02/06/2025.
+//  Copyright 2025 Simon Whitty
+//
+//  Distributed under the permissive MIT license
+//  Get the latest version from here:
+//
+//  https://github.com/swhitty/swift-timeout
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+#if compiler(>=6)
+
+extension Task<Never, Never> {
+
+    private typealias State = (isCancelled: Bool, continuation: CheckedContinuation<Never, any Error>?)
+
+    static func sleepIndefinitely() async throws -> Never {
+        let state = Mutex<State>((isCancelled: false, continuation: nil))
+        return try await withTaskCancellationHandler {
+            try await withCheckedThrowingContinuation { continuation in
+                let isCancelled = state.withLock {
+                    if $0.isCancelled {
+                        return true
+                    } else {
+                        $0.continuation = continuation
+                        return false
+                    }
+                }
+                if isCancelled {
+                    continuation.resume(throwing: _Concurrency.CancellationError())
+                }
+            }
+        } onCancel: {
+            let continuation = state.withLock {
+                $0.isCancelled = true
+                return $0.continuation
+            }
+            continuation?.resume(throwing: _Concurrency.CancellationError())
+        }
+    }
+}
+
+#endif

Tests/Task+SleepIndefinitelyTests.swift

@@ -0,0 +1,68 @@
+//
+//  Task+SleepIndefinitelyTests.swift
+//  swift-timeout
+//
+//  Created by Simon Whitty on 02/06/2025.
+//  Copyright 2025 Simon Whitty
+//
+//  Distributed under the permissive MIT license
+//  Get the latest version from here:
+//
+//  https://github.com/swhitty/swift-timeout
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+#if canImport(Testing)
+@testable import Timeout
+import Foundation
+import Testing
+
+struct TaskSleepIndefinitelyTests {
+
+    @Test
+    func throwsWhenInitiallyCancelled() async {
+        let task = Task {
+            try? await Task.sleep(nanoseconds: 60_000_000_000)
+            try await Task.sleepIndefinitely()
+        }
+
+        task.cancel()
+
+        await #expect(throws: CancellationError.self) {
+            try await task.value
+        }
+    }
+
+    @Test
+    func throwsWhenCancelled() async {
+        let task = Task {
+            try await Task.sleepIndefinitely()
+        }
+
+        try? await Task.sleep(nanoseconds: 200_000)
+        task.cancel()
+
+        await #expect(throws: CancellationError.self) {
+            try await task.value
+        }
+    }
+}
+
+#endif