Files
container/Sources/SendableProperty/SendableProperty.swift
T
Dmitry Kovba f245ae63b3 Improve @SendableProperty (#91)
This PR ensures that we enter a lock inside the `@SendableProperty`
implementation as soon as we access a computed property. Additionally,
it mirrors the access level of the original property. Both changes are
required for [improved
accuracy](https://github.com/apple/container/pull/144) of progress
updates in container. Additionally, it should resolve
https://github.com/apple/containerization/issues/60 that occurs on
certain configurations.

Please tag as 0.1.1 after merging.
2025-06-11 14:13:21 -04:00

47 lines
1.8 KiB
Swift

//===----------------------------------------------------------------------===//
// Copyright © 2025 Apple Inc. and the Containerization project authors.
// All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//===----------------------------------------------------------------------===//
// `Foundation` will be automatically imported with `SendableProperty`.
@_exported import Foundation
// A declaration of the `@SendableProperty` macro.
@attached(peer, names: arbitrary)
@attached(accessor)
public macro SendableProperty() = #externalMacro(module: "SendablePropertyMacros", type: "SendablePropertyMacro")
/// A synchronization primitive that protects shared mutable state via mutual exclusion.
public final class Synchronized<T>: @unchecked Sendable {
private let lock = NSLock()
private var value: T
/// Creates a new instance.
/// - Parameter value: The initial value.
public init(_ value: T) {
self.value = value
}
/// Calls the given closure after acquiring the lock and returns its value.
/// - Parameter body: The body of code to execute while the lock is held.
public func withLock<R>(_ body: (inout T) throws -> R) rethrows -> R {
lock.lock()
defer {
lock.unlock()
}
return try body(&value)
}
}