Я решил цель, создав управляемую настраиваемую операцию.
Теперь мы можем поставить в очередь c операций облачной базы данных точно так же
let privateSubscriptionOperation = SubscriptionOperation(type: .private)
let sharedSubscriptionOperation = SubscriptionOperation(type: .shared)
operationQueue.addOperation(privateSubscriptionOperation)
operationQueue.addOperation(privateSubscriptionOperation)
Прежде всего, class
class CKDatabaseControlledOperation: Operation {
let databaseType: DatabaseType
let database: CKDatabase
private var _finished = false
private var _executing = false
init(type: DatabaseType) {
databaseType = type
switch type {
case .private:
database = CKContainer.default().privateCloudDatabase
case .shared:
database = CKContainer.default().sharedCloudDatabase
}
}
override var isExecuting: Bool {
get {
return !_executing
}
set {
willChangeValue(forKey: "isExecuting") // This must match the overriden variable
_executing = newValue
didChangeValue(forKey: "isExecuting") // This must match the overriden variable
}
}
override var isFinished: Bool {
get {
return _finished
}
set {
willChangeValue(forKey: "isFinished") // This must match the overriden variable
_finished = newValue
didChangeValue(forKey: "isFinished") // This must match the overriden variable
}
}
func stopOperation() {
isFinished = true
isExecuting = false
}
func startOperation() {
isFinished = false
isExecuting = true
}
enum DatabaseType: String {
case `private` = "private-changes"
case shared = "shared-changes"
}
}
И тогда мы можем создать любую операцию с базой данных (подписка в этом примере, но будет работать с любой)
class SubscriptionOperation: CKDatabaseControlledOperation {
override func main() {
startOperation() //Operation starts
let subscription = CKDatabaseSubscription(subscriptionID: databaseType.rawValue)
//...set any needed stuff like NotificationInfo
let operation = CKModifySubscriptionsOperation(subscriptionsToSave: [subscription], subscriptionIDsToDelete: [])
operation.modifySubscriptionsCompletionBlock = { [unowned self] subscriptions, subscriptionIDs, error in
//Handle errors
self.stopOperation() //Operation ends
}
database.add(operation)
}
}