Files
swift-mirror/stdlib/public/Concurrency/PartialAsyncTask.swift
Kavon Farvardin fabd45e7c3 [concurrency] add resume<E: Error>(with: Result<T, E>) to UnsafeThrowingContinuation
A handy overload that allows one to return a Result<> to
a continuation without needing to manually unwrap it in client code.

Resolves rdar://71870249
2021-01-06 15:01:14 -08:00

114 lines
3.1 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
/// A partial task is a unit of scheduleable work.
@frozen
public struct PartialAsyncTask {
private var context: Builtin.Job
public func run() { }
}
@frozen
public struct UnsafeContinuation<T> {
@usableFromInline internal var context: Builtin.RawUnsafeContinuation
@_alwaysEmitIntoClient
internal init(_ context: Builtin.RawUnsafeContinuation) {
self.context = context
}
@_silgen_name("swift_continuation_resume")
public func resume(returning value: __owned T)
}
@frozen
public struct UnsafeThrowingContinuation<T> {
@usableFromInline internal var context: Builtin.RawUnsafeContinuation
@_alwaysEmitIntoClient
internal init(_ context: Builtin.RawUnsafeContinuation) {
self.context = context
}
@_silgen_name("swift_continuation_throwingResume")
public func resume(returning: __owned T)
@_silgen_name("swift_continuation_throwingResumeWithError")
public func resume(throwing: __owned Error)
public func resume<E: Error>(with result: Result<T, E>) {
switch result {
case .success(let val):
self.resume(returning: val)
case .failure(let err):
self.resume(throwing: err)
}
}
}
#if _runtime(_ObjC)
// Intrinsics used by SILGen to resume or fail continuations
// for
@_alwaysEmitIntoClient
internal func _resumeUnsafeContinuation<T>(
_ continuation: UnsafeContinuation<T>,
_ value: __owned T
) {
continuation.resume(returning: value)
}
@_alwaysEmitIntoClient
internal func _resumeUnsafeThrowingContinuation<T>(
_ continuation: UnsafeThrowingContinuation<T>,
_ value: __owned T
) {
continuation.resume(returning: value)
}
@_alwaysEmitIntoClient
internal func _resumeUnsafeThrowingContinuationWithError<T>(
_ continuation: UnsafeThrowingContinuation<T>,
_ error: __owned Error
) {
continuation.resume(throwing: error)
}
#endif
/// The operation functions must resume the continuation *exactly once*.
///
/// The continuation will not begin executing until the operation function returns.
@_alwaysEmitIntoClient
public func withUnsafeContinuation<T>(
_ fn: (UnsafeContinuation<T>) -> Void
) async -> T {
return await Builtin.withUnsafeContinuation {
fn(UnsafeContinuation<T>($0))
}
}
/// The operation functions must resume the continuation *exactly once*.
///
/// The continuation will not begin executing until the operation function returns.
@_alwaysEmitIntoClient
public func withUnsafeThrowingContinuation<T>(
_ fn: (UnsafeThrowingContinuation<T>) -> Void
) async throws -> T {
return try await Builtin.withUnsafeThrowingContinuation {
fn(UnsafeThrowingContinuation<T>($0))
}
}