Sources/SPTDataLoaderSwift/DataLoader.swift

// Copyright 2015-2023 Spotify AB
//
// 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

/// A protocol that provides data request handling.
public protocol DataLoader {
    /// The executed requests currently awaiting a response.
    var activeRequests: [Request] { get }

    /// Creates a `Request` that can be used to retrieve the contents of a URL.
    /// - Parameter url: The `URL` for the request.
    /// - Parameter sourceIdentifier: The identifier for the request source. May be `nil`.
    /// - Returns: A new `Request` instance.
    func request(_ url: URL, sourceIdentifier: String?) -> Request

    /// Cancels all requests that have been executed and are awaiting a response.
    func cancelActiveRequests()
}

public extension SPTDataLoaderFactory {
    /// Convenience method for creating a Swift `DataLoader`.
    /// - Parameter responseQueue: The `DispatchQueue` on which to perform response handling.
    /// - Returns: A new `DataLoader` instance.
    func makeDataLoader(responseQueue: DispatchQueue = .global()) -> DataLoader {
        let sptDataLoader = createDataLoader()
        let dataLoaderWrapper = DataLoaderWrapper(dataLoader: sptDataLoader)

        sptDataLoader.delegate = dataLoaderWrapper
        sptDataLoader.delegateQueue = responseQueue

        return dataLoaderWrapper
    }
}