//
//  ChainOperation.swift
//  RAD
//
//  Copyright 2018 NPR
//
//  Licensed under the Apache License, Version 2.0 (the "License"); you may not use
//  this file except in compliance with the License. You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software distributed under the
//  License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
//  either express or implied. See the License for the specific language governing permissions
//  and limitations under the License.
//

import Foundation

/// An operation which converts input into output.
class ChainOperation<Input, Output>: InputOperation<Input>,
OutputOperationType {
    typealias OutputType = Output

    var output: Output?
    var chainedOperations =
        WeakReferenceContainer<InputOperation<OutputType>>()

    override func cancel() {
        cancelChainedOperations()

        super.cancel()
    }

    override func finish(with error: Error? = nil) {
        willFinish(with: error)

        super.finish(with: error)
    }
}
