Define the PresentationController and AdaptivePresentationControllerDelegate interfaces

Add the declarations for the `PresentationController` and associated
delegate.  These types are required to make progress towards
presentation of view controllers.

Author: compnerd

Sources/SwiftWin32/App and Environment/AdaptivePresentationControllerDelegate.swift

@@ -0,0 +1,168 @@
+// Copyright © 2021 Saleem Abdulrasool <[email protected]>
+// SPDX-License-Identifier: BSD-3-Clause
+
+/// A set of methods that, in conjunction with a presentation controller,
+/// determine how to respond to trait changes in your application.
+public protocol AdaptivePresentationControllerDelegate: AnyObject {
+  // MARK - Adapting the Presentation Style
+
+  /// Asks the delegate for the presentation style to use when the specified set
+  /// of traits are active.
+  ///
+  /// The presentation controller calls this method when the traits of the
+  /// current environment are about to change. Your implementation of this
+  /// method can return the preferred presentation style to use for the
+  /// specified traits. If you do not return one of the allowed styles, the
+  /// presentation controller uses its preferred default style.
+  ///
+  /// If you do not implement this method in your delegate, the framework calls
+  /// the `adaptivePresentationStyle(for:)` method instead.
+  func adaptivePresentationStyle(for controller: PresentationController,
+                                 traitCollection: TraitCollection)
+      -> ModalPresentationStyle
+
+  /// Asks the delegate for the new presentation style to use.
+  ///
+  /// Use the `adaptivePresentationStyle(for:traitCollection:)` method to handle
+  /// all trait changes instead of this method. If you do not implement that
+  /// method, you can use this method to change the presentation style when
+  /// transitioning to a horizontally compact environment.
+  ///
+  /// If you do not implement this method or if you return an invalid style, the
+  /// current presentation controller returns its preferred default style.
+  func adaptivePresentationStyle(for controller: PresentationController)
+      -> ModalPresentationStyle
+
+  // MARK - Adapting the View Controller
+
+  /// Asks the delegate for the view controller to display when adapting to the
+  /// specified presentation style.
+  ///
+  /// When a size class change causes a change to the underlying presentation
+  /// style, the presentation controller calls this method to ask for the view
+  /// controller to display in that new style. This method is your opportunity
+  /// to replace the current view controller with one that is better suited for
+  /// the new presentation style. For example, you might use this method to
+  /// insert a navigation controller into your view hierarchy to facilitate
+  /// pushing new view controllers more easily in the compact environment. In
+  /// that instance, you would return a navigation controller whose root view
+  /// controller is the currently presented view controller. You could also
+  /// return an entirely different view controller if you prefer.
+  ///
+  /// If you do not implement this method or your implementation returns `nil`,
+  /// the presentation controller uses its existing presented view controller.
+  func presentationController(_ controller: PresentationController,
+                              viewControllerForAdaptivePresentationStyle style: ModalPresentationStyle)
+      -> ViewController?
+
+  // MARK - Responding to Adaptive Transitions
+
+  /// Notifies the delegate that an adaptivity-related transition is about to
+  /// occur.
+  ///
+  /// When a size class change occurs, the framework calls this method to let
+  /// you know how the presentation controller will adapt. Use this method to
+  /// make any additional changes. For example, you might use the transition
+  /// coordinator object to create additional animations for the transition.
+  func presentationController(_ presentationController: PresentationController,
+                              willPresentWithAdaptiveStyle style: ModalPresentationStyle,
+                              transitionCoordinator: ViewControllerTransitionCoordinator?)
+
+  /// Notifies the delegate that a user-initiated attempt to dismiss a view was
+  /// prevented.
+  ///
+  /// The framework supports refusing to dismiss a presentation when the
+  /// `presentationController.isModalInPresentation` returns `true` or
+  /// `presentationControllerShouldDismiss(_:)` returns `false`.
+  ///
+  /// Use this method to inform the user why the presentation can't be
+  /// dismissed, for example, by presenting an instance of `AlertController`.
+  func presentationControllerDidAttemptToDismiss(_ presentationController: PresentationController)
+
+  /// Asks the delegate for permission to dismiss the presentation.
+  ///
+  /// The system may call this method at any time. This method isn't guaranteed
+  /// to be followed by a call to `presentationControllerWillDismiss(_:)` or
+  /// `presentationControllerDidDismiss(_:)`. Make sure that your implementation
+  /// of this method returns quickly.
+  func presentationControllerShouldDismiss(_ presentationController: PresentationController)
+      -> Bool
+
+  /// Notifies the delegate after a presentation is dismissed.
+  ///
+  /// This method is not called if the presentation is dismissed
+  /// programmatically.
+  func presentationControllerDidDismiss(_ presentationController: PresentationController)
+
+  /// Notifies the delegate before a presentation is dismissed.
+  ///
+  /// You can use this method to set up animations or interaction notifications
+  /// with the `presentationController`'s `transitionCoordinator`.
+  ///
+  /// This method is not called if the presentation is dismissed
+  /// programmatically.
+  func presentationControllerWillDismiss(_ presentationController: PresentationController)
+
+  // MARK - Preparing the Adaptive Presentation Controller
+
+  /// Provides an opportunity to configure the adaptive presentation controller
+  /// after an adaptivity change.
+  ///
+  /// The system calls this method during adaptation so the delegate can
+  /// configure properties of the adaptive presentation controller before it
+  /// presents.
+  ///
+  /// For example, the system automatically adapts a view controller that
+  /// presents as a popover in standard size classes to a sheet in compact size
+  /// classes. You can implement this method to customize the sheet's
+  /// properties before it presents.
+  func presentationController(_ presentationController: PresentationController,
+                              prepare adaptivePresentationController: PresentationController)
+}
+
+extension AdaptivePresentationControllerDelegate {
+  public func adaptivePresentationStyle(for controller: PresentationController,
+                                        traitCollection: TraitCollection)
+      -> ModalPresentationStyle {
+    return self.adaptivePresentationStyle(for: controller)
+  }
+
+  public func adaptivePresentationStyle(for controller: PresentationController)
+      -> ModalPresentationStyle {
+    return controller.presentationStyle
+  }
+}
+
+extension AdaptivePresentationControllerDelegate {
+  public func presentationController(controller: PresentationController,
+                                     viewControllerForAdaptivePresentationStyle style: ModalPresentationStyle)
+      -> ViewController? {
+    return controller.presentedViewController
+  }
+}
+
+extension AdaptivePresentationControllerDelegate {
+  public func presentationController(_ controller: PresentationController,
+                                     willPresentWithAdaptiveStyle style: ModalPresentationStyle,
+                                     transitionCoordinator: ViewControllerTransitionCoordinator?) {
+  }
+
+  public func presentationControllerDidAttemptToDismiss(_ presentationController: PresentationController) {
+  }
+
+  public func presentationControllerShouldDismiss(_ presentationController: PresentationController) -> Bool {
+    return true
+  }
+
+  public func presentationControllerDidDismiss(_ presentationController: PresentationController) {
+  }
+
+  public func presentationControllerWillDismiss(_ presentationController: PresentationController) {
+  }
+}
+
+extension AdaptivePresentationControllerDelegate {
+  public func presentationController(_ presentationController: PresentationController,
+                                     prepare adaptivePresentationController: PresentationController) {
+  }
+}