foundationdb/flow/FlowCheckedContinuation.swift

57 lines
1.4 KiB
Swift

import Flow
@_expose(Cxx)
public struct ExposeVoidConf<T> {
let x: CInt
}
// FIXME: return Void? for conformance instead once header supports stdlib types.
@_expose(Cxx)
// This function ensures that the value witness table for `Void` to C++ is
// exposed in the generated C++ header.
public func _exposeVoidValueTypeConformanceToCpp(_ val: ExposeVoidConf<Void>) {
}
@_expose(Cxx)
public struct FlowCheckedContinuation<T> {
public typealias CC = CheckedContinuation<T, Swift.Error>
var cc: CC?
public init() {}
public init(_ cc: CC) {
self.cc = cc
}
public mutating func set(_ other: FlowCheckedContinuation<T>) {
// precondition: other continuation must be set.
assert(other.cc != nil)
cc = other.cc
}
public func resume(returning value: T) {
// precondition: continuation must be set.
assert(cc != nil)
cc!.resume(returning: value)
}
public func resumeThrowing(_ value: Flow.Error) {
// precondition: continuation must be set.
assert(cc != nil)
// TODO: map errors.
cc!.resume(throwing: GeneralFlowError(value))
}
}
public struct GeneralFlowError: Swift.Error {
let underlying: Flow.Error?
public init() {
self.underlying = nil
}
public init(_ underlying: Flow.Error) {
self.underlying = underlying
}
}