Files
swift-mirror/stdlib/public/Concurrency/Actor.swift
John McCall 945011d39f Handle default actors by special-casing layout in IRGen instead
of adding a property.

This better matches what the actual implementation expects,
and it avoids some possibilities of weird mismatches.  However,
it also requires special-case initialization, destruction, and
dynamic-layout support, none of which I've added yet.

In order to get NSObject default actor subclasses to use Swift
refcounting (and thus avoid the need for the default actor runtime
to generally use ObjC refcounting), I've had to introduce a
SwiftNativeNSObject which we substitute as the superclass when
inheriting directly from NSObject.  This is something we could
do in all NSObject subclasses; for now, I'm just doing it in
actors, although it's all actors and not just default actors.
We are not yet taking advantage of our special knowledge of this
class anywhere except the reference-counting code.

I went around in circles exploring a number of alternatives for
doing this; at one point I basically had a completely parallel
"ForImplementation" superclass query.  That proved to be a lot
of added complexity and created more problems than it solved.
We also don't *really* get any benefit from this subclassing
because there still wouldn't be a consistent superclass for all
actors.  So instead it's very ad-hoc.
2020-12-02 18:47:13 -05:00

41 lines
1.7 KiB
Swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2020 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
@_implementationOnly import _SwiftConcurrencyShims
/// Common protocol to which all actor classes conform.
///
/// The \c Actor protocol provides the core functionality of an actor class,
/// which involves enqueuing new partial tasks to be executed at some
/// point. Actor classes implicitly conform to this protocol as part of their
/// primary class definition.
public protocol Actor: AnyObject {
/// Enqueue a new partial task that will be executed in the actor's context.
func enqueue(partialTask: PartialAsyncTask)
}
/// Called to initialize the default actor instance in an actor.
/// The implementation will call this within the actor's initializer.
@_silgen_name("swift_defaultActor_initialize")
public func _defaultActorInitialize(_ actor: AnyObject)
/// Called to destroy the default actor instance in an actor.
/// The implementation will call this within the actor's deinit.
@_silgen_name("swift_defaultActor_destroy")
public func _defaultActorDestroy(_ actor: AnyObject)
/// Called by the synthesized implementation of enqueue(partialTask:).
@_silgen_name("swift_defaultActor_enqueue")
public func _defaultActorEnqueue(partialTask: PartialAsyncTask,
actor: AnyObject)