Files
swift-mirror/stdlib/public/Concurrency/Actor.swift
Allan Shortlidge ba3cd79b6f Concurrency: Remove superflous _SwiftConcurrencyShims imports.
The `_SwiftConcurrencyShims` module was imported `@_implementationOnly` which
was causing warnings to be emitted during the stdlib build. The module
currently serves no purpose; the only declaration it contains is a defunct
`_SwiftContext` struct which is not referenced by anything. The module needs to
continue to exist for source compatibility, though, since it is part of the
toolchain and imported publicly from other modules.
2024-09-09 12:20:13 -07:00

112 lines
4.5 KiB
Swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2020-2022 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
import Swift
/// Common marker protocol providing a shared "base" for both (local) `Actor`
/// and (potentially remote) `DistributedActor` types.
///
/// The `AnyActor` marker protocol generalizes over all actor types, including
/// distributed ones. In practice, this protocol can be used to restrict
/// protocols, or generic parameters to only be usable with actors, which
/// provides the guarantee that calls may be safely made on instances of given
/// type without worrying about the thread-safety of it -- as they are
/// guaranteed to follow the actor-style isolation semantics.
///
/// While both local and distributed actors are conceptually "actors", there are
/// some important isolation model differences between the two, which make it
/// impossible for one to refine the other.
@available(SwiftStdlib 5.1, *)
@available(*, deprecated, message: "Use 'any Actor' with 'DistributedActor.asLocalActor' instead")
@available(swift, obsoleted: 6.0, message: "Use 'any Actor' with 'DistributedActor.asLocalActor' instead")
public typealias AnyActor = AnyObject & Sendable
/// Common protocol to which all actors conform.
///
/// The `Actor` protocol generalizes over all `actor` types. Actor types
/// implicitly conform to this protocol.
///
/// ### Actors and SerialExecutors
/// By default, actors execute tasks on a shared global concurrency thread pool.
/// This pool is shared by all default actors and tasks, unless an actor or task
/// specified a more specific executor requirement.
///
/// It is possible to configure an actor to use a specific ``SerialExecutor``,
/// as well as impact the scheduling of default tasks and actors by using
/// a ``TaskExecutor``.
///
/// - SeeAlso: ``SerialExecutor``
/// - SeeAlso: ``TaskExecutor``
@available(SwiftStdlib 5.1, *)
public protocol Actor: AnyObject, Sendable {
/// Retrieve the executor for this actor as an optimized, unowned
/// reference.
///
/// This property must always evaluate to the same executor for a
/// given actor instance, and holding on to the actor must keep the
/// executor alive.
///
/// This property will be implicitly accessed when work needs to be
/// scheduled onto this actor. These accesses may be merged,
/// eliminated, and rearranged with other work, and they may even
/// be introduced when not strictly required. Visible side effects
/// are therefore strongly discouraged within this property.
///
/// - SeeAlso: ``SerialExecutor``
/// - SeeAlso: ``TaskExecutor``
nonisolated var unownedExecutor: UnownedSerialExecutor { get }
}
/// Called to initialize the default actor instance in an actor.
/// The implementation will call this within the actor's initializer.
@available(SwiftStdlib 5.1, *)
@_silgen_name("swift_defaultActor_initialize")
public func _defaultActorInitialize(_ actor: AnyObject)
@available(SwiftStdlib 5.9, *)
@_silgen_name("swift_nonDefaultDistributedActor_initialize")
public func _nonDefaultDistributedActorInitialize(_ actor: AnyObject)
/// Called to destroy the default actor instance in an actor.
/// The implementation will call this within the actor's deinit.
@available(SwiftStdlib 5.1, *)
@_silgen_name("swift_defaultActor_destroy")
public func _defaultActorDestroy(_ actor: AnyObject)
@available(SwiftStdlib 5.1, *)
@_silgen_name("swift_task_enqueueMainExecutor")
@usableFromInline
internal func _enqueueOnMain(_ job: UnownedJob)
#if $Macros
/// Produce a reference to the actor to which the enclosing code is
/// isolated, or `nil` if the code is nonisolated.
///
/// If the type annotation provided for `#isolation` is not `(any Actor)?`,
/// the type must match the enclosing actor type. If no type annotation is
/// provided, the type defaults to `(any Actor)?`.
@available(SwiftStdlib 5.1, *)
@freestanding(expression)
public macro isolation<T>() -> T = Builtin.IsolationMacro
#endif
#if $IsolatedAny
@_alwaysEmitIntoClient
@available(SwiftStdlib 5.1, *)
public func extractIsolation<each Arg, Result>(
_ fn: @escaping @isolated(any) (repeat each Arg) async throws -> Result
) -> (any Actor)? {
return Builtin.extractFunctionIsolation(fn)
}
#endif