Move AsyncOperation into Operations static library and add separate tests

1 files changed, 72 insertions, 0 deletions

diff --git a/ios/Operations/AlertPresenter.swift b/ios/Operations/AlertPresenter.swift
new file mode 100644
index 0000000000..6bf4470e23
--- /dev/null
+++ b/ios/Operations/AlertPresenter.swift
@@ -0,0 +1,72 @@
+//
+//  AlertPresenter.swift
+//  MullvadVPN
+//
+//  Created by pronebird on 04/06/2020.
+//  Copyright © 2020 Mullvad VPN AB. All rights reserved.
+//
+
+#if canImport(UIKit)
+
+import UIKit
+
+public final class AlertPresenter {
+    static let alertControllerDidDismissNotification = Notification
+        .Name("UIAlertControllerDidDismiss")
+
+    private let operationQueue: OperationQueue = {
+        let operationQueue = AsyncOperationQueue()
+        operationQueue.name = "AlertPresenterQueue"
+        operationQueue.maxConcurrentOperationCount = 1
+        return operationQueue
+    }()
+
+    private static let initClass: Void = {
+        /// Swizzle `viewDidDisappear` on `UIAlertController` in order to be able to
+        /// detect when the controller disappears.
+        /// The event is broadcasted via `AlertPresenter.alertControllerDidDismissNotification` notification.
+        swizzleMethod(
+            aClass: UIAlertController.self,
+            originalSelector: #selector(UIAlertController.viewDidDisappear(_:)),
+            newSelector: #selector(UIAlertController.alertPresenter_viewDidDisappear(_:))
+        )
+    }()
+
+    public init() {
+        _ = Self.initClass
+    }
+
+    public func enqueue(
+        _ alertController: UIAlertController,
+        presentingController: UIViewController,
+        presentCompletion: (() -> Void)? = nil
+    ) {
+        let operation = PresentAlertOperation(
+            alertController: alertController,
+            presentingController: presentingController,
+            presentCompletion: presentCompletion
+        )
+
+        operationQueue.addOperation(operation)
+    }
+
+    public func cancelAll() {
+        operationQueue.cancelAllOperations()
+    }
+}
+
+private extension UIAlertController {
+    @objc dynamic func alertPresenter_viewDidDisappear(_ animated: Bool) {
+        // Call super implementation
+        alertPresenter_viewDidDisappear(animated)
+
+        if presentingViewController == nil {
+            NotificationCenter.default.post(
+                name: AlertPresenter.alertControllerDidDismissNotification,
+                object: self
+            )
+        }
+    }
+}
+
+#endif