import Foundation extension UsageStore { private nonisolated static let probeTimeoutQueue = DispatchQueue( label: "com.steipete.codexbar.probe-timeouts", qos: .userInitiated) private final class ProbeTimeoutRace: @unchecked Sendable { private let lock = NSLock() private var continuation: CheckedContinuation<String, Never>? private var result: String? private var cancellations: [() -> Void] = [] func install(_ continuation: CheckedContinuation<String, Never>) { let result: String? = self.lock.withLock { if let result = self.result { return result } self.continuation = continuation return nil } if let result { continuation.resume(returning: result) } } func install(_ task: Task<Void, Never>) { self.installCancellation { task.cancel() } } func install(_ workItem: DispatchWorkItem) { self.installCancellation { workItem.cancel() } } private func installCancellation(_ cancellation: @escaping () -> Void) { let shouldCancel = self.lock.withLock { guard self.result == nil else { return true } self.cancellations.append(cancellation) return false } if shouldCancel { cancellation() } } func complete(with result: String) { let completion = self.lock.withLock { guard self.result == nil else { return (nil as CheckedContinuation<String, Never>?, [] as [() -> Void]) } self.result = result let continuation = self.continuation self.continuation = nil let cancellations = self.cancellations self.cancellations.removeAll() return (continuation, cancellations) } completion.1.forEach { $0() } completion.0?.resume(returning: result) } } nonisolated static func runWithTimeout( seconds: Double, operation: @escaping @Sendable () async -> String) async -> String { let timeoutMessage = "Probe timed out after \(Int(seconds))s" let race = ProbeTimeoutRace() return await withTaskCancellationHandler { await withCheckedContinuation { continuation in race.install(continuation) race.install(Task { let result = await operation() race.complete(with: result) }) // A Swift task-based timer can be delayed when the cooperative pool is // saturated by blocking probes. Dispatch keeps the timeout wall-clock bounded. let timeoutWorkItem = DispatchWorkItem { race.complete(with: timeoutMessage) } race.install(timeoutWorkItem) Self.probeTimeoutQueue.asyncAfter( deadline: .now() + max(seconds, 0), execute: timeoutWorkItem) } } onCancel: { race.complete(with: timeoutMessage) } }}
import Foundation
extension UsageStore {
private nonisolated static let probeTimeoutQueue = DispatchQueue(
label: "com.steipete.codexbar.probe-timeouts",
qos: .userInitiated)
private final class ProbeTimeoutRace: @unchecked Sendable {
private let lock = NSLock()
private var continuation: CheckedContinuation<String, Never>?
private var result: String?
private var cancellations: [() -> Void] = []
func install(_ continuation: CheckedContinuation<String, Never>) {
let result: String? = self.lock.withLock {
if let result = self.result {
return result
}
self.continuation = continuation
return nil
}
if let result {
continuation.resume(returning: result)
}
}
func install(_ task: Task<Void, Never>) {
self.installCancellation {
task.cancel()
}
}
func install(_ workItem: DispatchWorkItem) {
self.installCancellation {
workItem.cancel()
}
}
private func installCancellation(_ cancellation: @escaping () -> Void) {
let shouldCancel = self.lock.withLock {
guard self.result == nil else { return true }
self.cancellations.append(cancellation)
return false
}
if shouldCancel {
cancellation()
}
}
func complete(with result: String) {
let completion = self.lock.withLock {
guard self.result == nil else {
return (nil as CheckedContinuation<String, Never>?, [] as [() -> Void])
}
self.result = result
let continuation = self.continuation
self.continuation = nil
let cancellations = self.cancellations
self.cancellations.removeAll()
return (continuation, cancellations)
}
completion.1.forEach { $0() }
completion.0?.resume(returning: result)
}
}
nonisolated static func runWithTimeout(
seconds: Double,
operation: @escaping @Sendable () async -> String) async -> String
{
let timeoutMessage = "Probe timed out after \(Int(seconds))s"
let race = ProbeTimeoutRace()
return await withTaskCancellationHandler {
await withCheckedContinuation { continuation in
race.install(continuation)
race.install(Task {
let result = await operation()
race.complete(with: result)
})
// A Swift task-based timer can be delayed when the cooperative pool is
// saturated by blocking probes. Dispatch keeps the timeout wall-clock bounded.
let timeoutWorkItem = DispatchWorkItem {
race.complete(with: timeoutMessage)
}
race.install(timeoutWorkItem)
Self.probeTimeoutQueue.asyncAfter(
deadline: .now() + max(seconds, 0),
execute: timeoutWorkItem)
}
} onCancel: {
race.complete(with: timeoutMessage)
}
}
}