How would I declare a closure that retrieves records from CloudKit that iteratively calls itself until all the records are fetched? The following code does that, except I get an error saying
Variable used within its own initial value
at the line where I assign the closure queryCompletionBlock to the property by that same name of the query operation within the declaration of the closure itself. Basically, I get an error because I call the closure within itself in the declaration of the closure before the closure is declared.
let predicate = NSPredicate(value: true)
let query = CKQuery(recordType: DatabaseNameStrings.recordTypeEntry, predicate: predicate)
let queryOperation = CKQueryOperation(query: query)
queryOperation.desiredKeys = [DatabaseNameStrings.fieldNameCreatedAt, DatabaseNameStrings.fieldNameText]
let queryCompletionBlock = {
(cursor: CKQueryOperation.Cursor?, error: Error?) in
if let error = error {
print(error.localizedDescription)
} else if let cursor = cursor {
let queryOperation = CKQueryOperation(cursor: cursor)
queryOperation.desiredKeys = [DatabaseNameStrings.fieldNameCreatedAt, DatabaseNameStrings.fieldNameText]
queryOperation.queryCompletionBlock = queryCompletionBlock // Error message "Variable used within its own initial value"
queryOperationQueue.addOperation(queryOperation)
}
}
queryOperation.queryCompletionBlock = queryCompletionBlock
queryOperationQueue.addOperation(queryOperation)
One option that should work is to reference the queryCompletionBlock
of the original query operation.
let predicate = NSPredicate(value: true)
let query = CKQuery(recordType: DatabaseNameStrings.recordTypeEntry, predicate: predicate)
let queryOperation = CKQueryOperation(query: query)
queryOperation.desiredKeys = [DatabaseNameStrings.fieldNameCreatedAt, DatabaseNameStrings.fieldNameText]
let queryCompletionBlock = {
(cursor: CKQueryOperation.Cursor?, error: Error?) in
if let error = error {
print(error.localizedDescription)
} else if let cursor = cursor {
let newOperation = CKQueryOperation(cursor: cursor)
newOperation.desiredKeys = queryOperation.desiredKeys
newOperation.queryCompletionBlock = queryOperation.queryCompletionBlock
newOperationQueue.addOperation(newOperation)
}
}
queryOperation.queryCompletionBlock = queryCompletionBlock
queryOperationQueue.addOperation(queryOperation)