Dimitris C
73 lines
1.6 KiB
Swift
73 lines
1.6 KiB
Swift
//
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// Created by Dimitrios Chatzieleftheriou on 21/05/2020.
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// Copyright © 2020 Decimal. All rights reserved.
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//
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protocol Lock {
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func lock()
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func unlock()
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}
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extension Lock {
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// Execute a closure while acquiring a lock and returns the closure value
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func around<T>(_ closure: () -> T) -> T {
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lock(); defer { unlock() }
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return closure()
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}
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// Execute a closure while acquiring a lock
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func around(_ closure: () -> Void) {
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lock(); defer { unlock() }
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closure()
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}
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}
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/// A wrapper for `os_unfair_lock`
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final public class UnfairLock: Lock {
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private let unfairLock: os_unfair_lock_t
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public init() {
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unfairLock = .allocate(capacity: 1)
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unfairLock.initialize(to: os_unfair_lock())
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}
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deinit {
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unfairLock.deinitialize(count: 1)
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unfairLock.deallocate()
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}
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public func lock() {
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os_unfair_lock_lock(unfairLock)
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}
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public func unlock() {
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os_unfair_lock_unlock(unfairLock)
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}
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}
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@propertyWrapper
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final class Protected<Value> {
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private let lock = UnfairLock()
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private var value: Value
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init(wrappedValue: Value) {
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self.value = wrappedValue
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}
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var wrappedValue: Value {
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get { lock.around { value } }
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}
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var projectedValue: Protected<Value> { self }
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func read<Element>(_ closure: (Value) -> Element) -> Element {
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lock.around { closure(self.value) }
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}
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@discardableResult
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func write<Element>(_ closure: (inout Value) -> Element) -> Element {
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lock.around { closure(&self.value) }
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}
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}
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