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| @_implementationOnly import os | |
| // Backports the Swift interface around os_unfair_lock_t available in recent Darwin platforms | |
| // | |
| @available(iOS, deprecated: 16.0, message: "use OSAllocatedUnfairLock directly") | |
| @available(tvOS, deprecated: 16.0, message: "use OSAllocatedUnfairLock directly") | |
| @available(watchOS, deprecated: 9, message: "use OSAllocatedUnfairLock directly") | |
| @available(macOS, deprecated: 13.0, message: "use OSAllocatedUnfairLock directly") | |
| struct AllocatedUnfairLock<State> { | |
| private let storage: Storage | |
| init(initialState: State) { | |
| self.storage = Storage(initialState: initialState) | |
| } | |
| func withLock<R>(_ body: @Sendable (inout State) throws -> R) rethrows -> R where R: Sendable { | |
| os_unfair_lock_lock(storage.lock) | |
| defer { os_unfair_lock_unlock(storage.lock) } | |
| return try body(&storage.state) | |
| } | |
| private final class Storage { | |
| let lock: os_unfair_lock_t | |
| var state: State | |
| init(initialState: State) { | |
| self.lock = .allocate(capacity: 1) | |
| self.lock.initialize(to: os_unfair_lock()) | |
| self.state = initialState | |
| } | |
| deinit { | |
| self.lock.deinitialize(count: 1) | |
| self.lock.deallocate() | |
| } | |
| } | |
| } | |
| extension AllocatedUnfairLock where State == Void { | |
| init() { | |
| self.storage = .init(initialState: ()) | |
| } | |
| func lock() { | |
| os_unfair_lock_lock(storage.lock) | |
| } | |
| func unlock() { | |
| os_unfair_lock_unlock(storage.lock) | |
| } | |
| func withLock<R>(_ body: @Sendable () throws -> R) rethrows -> R where R: Sendable { | |
| os_unfair_lock_lock(storage.lock) | |
| defer { os_unfair_lock_unlock(storage.lock) } | |
| return try body() | |
| } | |
| } |
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