package-concurrency-helpers

3.0.0

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Various tools needed for concurrency (locks, async stream helpers, ...)

ordo-core-package

What's New

3.0.0

2023-10-17T16:09:31Z

3.0.0 (2023-10-17)

Concurrency helpers

Various concurrency related tools, including Lock and async stream additions etc.

To add to your project:

dependencies: [
    .package(url: "https://github.com/ordo-one/package-concurrency-helpers", .upToNextMajor(from: "0.0.1")),
]

and then add the dependency to your target, e.g.:

.executableTarget(
  name: "MyExecutableTarget",
  dependencies: [
  .product(name: "SwiftConcurrencyHelpers", package: "package-concurrency-helpers")
]),

Helpers provided:

Safely call a blocking function from an async context:

let result = await forBlockingFunc {
    // Call your blocking function here.
}

Run async code in a non-async context:

let result = runSync {
    await someFunction()
}

Simple locks, including a variant that sleeps while waiting for the lock:

let lock = Lock()

let result = lock.withLock {
    …
}

…and a variant that spins waiting for the lock:

let lock = Spinlock()

let result = lock.withLock {
    … // Make sure whatever you do here is quick; other threads may be busy waiting.
}

A simple thread-safe box for a value:

let safeValue = Protected(myValue)

safeValue.write {
    // Have exclusive access to the contents here.
    $0.someField = true
}

safeValue.read {
    // Have exclusive, read-only access to the contents here.
    if $0.someField {
        …
    }
}

An unsafe Sendable wrapper for value types:

var someNonSendable = …

let wrapper = UnsafeTransfer(someNonSendable)

Task.detached {
    let value = wrapper.wrappedValue
    // Use `value` here, instead of the original name `someNonSendable`.
}

There is also an UnsafeMutableTransfer variant, for mutable values.

Yield a value to an AsyncStream with back-pressure support (waiting in a Concurrency-safe way until the stream is ready to accept the message):
```
guard yieldWithBackPressure(message: …, to: continuation) else {
    // Stream was closed or this task has been cancelled.
}
```
A simple reference-typed box for value types:
```
let a = Box(5)
let b = a

b.value += 1

// 'b' and 'a' both now hold 6.
```
It inherits the Equatable, Comparable, CustomStringConvertible, and CustomDebugStringConvertible conformances of the contained type.
Determine if a debugger is attached (a Swift version of Apple's C AmIBeingDebugged):
```
if isBeingDebugged {
    // Running under, or attached by, a debugger of some kind.
} else {
    // *Probably* not being debugged.
}
```
Note that this is not foolproof; debuggers can hide themselves from detection.
A backport of Apple's AsyncStream.makeStream(of:bufferingPolicy:), to make it available in Swift 5.8 and earlier as well.
Calculate the next highest power of two, above a given integer:
```
let roundedUp = nearestPowerOf2(27)
// 'roundedUp' is 32.
```

Track the rate of an event, and run a closure every N events:

let monitor = ProcessingRate(interval: 10)

while true {
    monitor.checkpoint {
        // Runs every 10 calls to `checkpoint`.
        print("Current rate: \(monitor.ratePerSecond) Hz")
    }
}

Count events, then at designated checkpoints run a closure & reset the count if a set duration has passed since the last reset (or since the counter was created, if never before reset).

let monitor = TimeIntervalCounter(clock: ContinuousClock(),
                                  timeInterval: .seconds(5))

while true {
    if monitor.incremenet() {
        // It has been at least five seconds since the monitor was last reset.
    }

    monitor.checkpoint {
        // Runs at most once every five seconds.
        print("Current count: \(monitor.count)")
        // The count will automatically be reset to zero when this closure exits.
    }
}

Description

Swift Tools 5.8.0

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Last updated: Thu Apr 03 2025 01:52:21 GMT-0900 (Hawaii-Aleutian Daylight Time)