mattmassicotte/taskgate

Integration

Swift Package Manager:

dependencies: [
    .package(url: "https://github.com/mattmassicotte/TaskGate", branch: "main")
]

Usage

Gates are very intentionally non-Sendable. The purpose of a gate is to control tasks running concurrently within a single actor, and making them non-Sendable allows the compiler will help enforce that concept.

Note that trying to acquire an already-gated AsyncGate will deadlock your actor.

import TaskGate

actor MyActor {
  var value = 42
  let gate = AsyncGate()
  let recursiveGate = AsyncRecursiveGate()

  func hasCriticalSections() async {
    // no matter how many tasks call this method,
    // only one will be able to execute at a time
	await gate.withGate {
      self.value = await otherObject.getValue()
    }
  }

  func hasCriticalSectionsBlock() async {
    await recursiveGate.withGate {
      // acquiring this multiple times within the same task is safe
      await recursiveGate.withGate {
        self.value = await otherObject.getValue()
      }
    }
  }
}

Both of these gate types support priority escalation propagation to help avoid priority inversions. However, the API required to do this was introduced with SE-0462, which is only available in the 26 OSes and later.

It is important to note that gates cannot be used from a non-async context. Actually doing this would require some trickery, as they both only have async interfaces. But, if you find a way, perhaps via ObjC bridging, you should expect a crash.

Contributing and Collaboration

I would love to hear from you! Issues or pull requests work great. Both a [Matrix space][matrix] and [Discord][discord] are also available for live help, but I have a strong bias towards answering in the form of documentation.

I prefer collaboration, and would love to find ways to work together if you have a similar project.

I prefer indentation with tabs for improved accessibility. But, I'd rather you use the system you want and make a PR than hesitate because of whitespace.

By participating in this project you agree to abide by the Contributor Code of Conduct.

[build status]: https://github.com/mattmassicotte/Lock/actions [build status badge]: https://github.com/mattmassicotte/Lock/workflows/CI/badge.svg [platforms]: https://swiftpackageindex.com/mattmassicotte/Lock [platforms badge]: https://img.shields.io/endpoint?url=https%3A%2F%2Fswiftpackageindex.com%2Fapi%2Fpackages%2Fmattmassicotte%2FLock%2Fbadge%3Ftype%3Dplatforms [matrix]: https://matrix.to/#/%23chimehq%3Amatrix.org [matrix badge]: https://img.shields.io/matrix/chimehq%3Amatrix.org?label=Matrix [discord]: https://discord.gg/esFpX6sErJ [Semaphore]: https://github.com/groue/Semaphore [Queue]: https://github.com/mattmassicotte/Queue [Gate]: https://github.com/wadetregaskis/Gate

Package Metadata

Repository: mattmassicotte/taskgate

Default branch: main

README: README.md