feature: Added Uno support

build.cake

@@ -24,6 +24,7 @@ var packageWhitelist = new List<FilePath>
     MakeAbsolute(File("./src/ReactiveUI.Fody.Helpers/ReactiveUI.Fody.Helpers.csproj")),
     MakeAbsolute(File("./src/ReactiveUI.AndroidSupport/ReactiveUI.AndroidSupport.csproj")),
     MakeAbsolute(File("./src/ReactiveUI.XamForms/ReactiveUI.XamForms.csproj")),
+    MakeAbsolute(File("./src/ReactiveUI.Uno/ReactiveUI.Uno.csproj")),
 };
 
 if (IsRunningOnWindows())

src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.net461.approved.txt

@@ -1,5 +1,6 @@
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.AndroidSupport")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.Tests")]
+[assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.Uno")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.Winforms")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.Wpf")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.XamForms")]

src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.netcoreapp2.0.approved.txt

@@ -1,5 +1,6 @@
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.AndroidSupport")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.Tests")]
+[assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.Uno")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.Winforms")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.Wpf")]
 [assembly: System.Runtime.CompilerServices.InternalsVisibleToAttribute("ReactiveUI.XamForms")]

src/ReactiveUI.Uno/ActivationForViewFetcher.cs

@@ -0,0 +1,66 @@
+// Copyright (c) 2019 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using System;
+using System.Linq;
+using System.Reactive;
+using System.Reactive.Linq;
+using System.Reflection;
+
+using Windows.Foundation;
+using Windows.UI.Xaml;
+
+namespace ReactiveUI
+{
+    /// <summary>
+    /// ActiveationForViewFetcher is how ReactiveUI determine when a
+    /// View is activated or deactivated. This is usually only used when porting
+    /// ReactiveUI to a new UI framework.
+    /// </summary>
+    public class ActivationForViewFetcher : IActivationForViewFetcher
+    {
+        /// <inheritdoc/>
+        public int GetAffinityForView(Type view)
+        {
+            return typeof(FrameworkElement).GetTypeInfo().IsAssignableFrom(view.GetTypeInfo()) ? 10 : 0;
+        }
+
+        /// <inheritdoc/>
+        public IObservable<bool> GetActivationForView(IActivatable view)
+        {
+            var fe = view as FrameworkElement;
+
+            if (fe == null)
+            {
+                return Observable<bool>.Empty;
+            }
+
+#pragma warning disable SA1114 // Parameter list after.
+#if NETSTANDARD || MAC
+            var viewLoaded = Observable.FromEvent<RoutedEventHandler, bool>(
+#else
+            var viewLoaded = Observable.FromEvent<TypedEventHandler<DependencyObject, object>, bool>(
+#endif
+                eventHandler => (_, __) => eventHandler(true),
+                x => fe.Loading += x,
+                x => fe.Loading -= x);
+
+            var viewUnloaded = Observable.FromEvent<RoutedEventHandler, bool>(
+                handler =>
+                {
+                    void EventHandler(object sender, RoutedEventArgs e) => handler(false);
+                    return EventHandler;
+                },
+                x => fe.Unloaded += x,
+                x => fe.Unloaded -= x);
+
+            return viewLoaded
+                .Merge(viewUnloaded)
+                .Select(b => b ? fe.WhenAnyValue(x => x.IsHitTestVisible).SkipWhile(x => !x) : Observables.False)
+                .Switch()
+                .DistinctUntilChanged();
+        }
+    }
+}

src/ReactiveUI.Uno/CoreDispatcherScheduler.cs

@@ -0,0 +1,251 @@
+// Copyright (c) 2019 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+// <auto-generated />
+
+using System;
+using System.Collections.Generic;
+using System.Reactive.Disposables;
+using System.Runtime.ExceptionServices;
+using System.Text;
+using System.Threading;
+
+using Windows.UI.Core;
+using Windows.UI.Xaml;
+
+namespace System.Reactive.Concurrency
+{
+    /// <summary>
+    /// Represents an object that schedules units of work on a <see cref="CoreDispatcher"/>.
+    /// </summary>
+    /// <remarks>
+    /// This scheduler type is typically used indirectly through the <see cref="Linq.DispatcherObservable.ObserveOnDispatcher{TSource}(IObservable{TSource})"/> and <see cref="Linq.DispatcherObservable.SubscribeOnDispatcher{TSource}(IObservable{TSource})"/> methods that use the current Dispatcher.
+    /// </remarks>
+    [CLSCompliant(false)]
+    public sealed class CoreDispatcherScheduler : LocalScheduler, ISchedulerPeriodic
+    {
+        /// <summary>
+        /// Constructs a <see cref="CoreDispatcherScheduler"/> that schedules units of work on the given <see cref="CoreDispatcher"/>.
+        /// </summary>
+        /// <param name="dispatcher">Dispatcher to schedule work on.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="dispatcher"/> is <c>null</c>.</exception>
+        public CoreDispatcherScheduler(CoreDispatcher dispatcher)
+        {
+            Dispatcher = dispatcher ?? throw new ArgumentNullException(nameof(dispatcher));
+            Priority = CoreDispatcherPriority.Normal;
+        }
+
+        /// <summary>
+        /// Constructs a <see cref="CoreDispatcherScheduler"/> that schedules units of work on the given <see cref="CoreDispatcher"/> with the given priority.
+        /// </summary>
+        /// <param name="dispatcher">Dispatcher to schedule work on.</param>
+        /// <param name="priority">Priority for scheduled units of work.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="dispatcher"/> is <c>null</c>.</exception>
+        public CoreDispatcherScheduler(CoreDispatcher dispatcher, CoreDispatcherPriority priority)
+        {
+            Dispatcher = dispatcher ?? throw new ArgumentNullException(nameof(dispatcher));
+            Priority = priority;
+        }
+
+        /// <summary>
+        /// Gets the scheduler that schedules work on the <see cref="CoreDispatcher"/> associated with the current Window.
+        /// </summary>
+        public static CoreDispatcherScheduler Current
+        {
+            get
+            {
+                var window = Window.Current;
+                if (window == null)
+                {
+                    throw new InvalidOperationException("There is no current window that has been created.");
+                }
+
+                return new CoreDispatcherScheduler(window.Dispatcher);
+            }
+        }
+
+        /// <summary>
+        /// Gets the <see cref="CoreDispatcher"/> associated with the <see cref="CoreDispatcherScheduler"/>.
+        /// </summary>
+        public CoreDispatcher Dispatcher { get; }
+
+        /// <summary>
+        /// Gets the priority at which work is scheduled.
+        /// </summary>
+        public CoreDispatcherPriority Priority { get; }
+
+        /// <summary>
+        /// Schedules an action to be executed on the dispatcher.
+        /// </summary>
+        /// <typeparam name="TState">The type of the state passed to the scheduled action.</typeparam>
+        /// <param name="state">State passed to the action to be executed.</param>
+        /// <param name="action">Action to be executed.</param>
+        /// <returns>The disposable object used to cancel the scheduled action (best effort).</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="action"/> is <c>null</c>.</exception>
+        public override IDisposable Schedule<TState>(TState state, Func<IScheduler, TState, IDisposable> action)
+        {
+            if (action == null)
+            {
+                throw new ArgumentNullException(nameof(action));
+            }
+
+            var d = new SingleAssignmentDisposable();
+
+            var res = Dispatcher.RunAsync(Priority, () =>
+            {
+                if (!d.IsDisposed)
+                {
+                    try
+                    {
+                        d.Disposable = action(this, state);
+                    }
+                    catch (Exception ex)
+                    {
+                        //
+                        // Work-around for the behavior of throwing from RunAsync not propagating
+                        // the exception to the Application.UnhandledException event (as of W8RP)
+                        // as our users have come to expect from previous XAML stacks using Rx.
+                        //
+                        // If we wouldn't do this, there'd be an observable behavioral difference
+                        // between scheduling with TimeSpan.Zero or using this overload.
+                        //
+                        // For scheduler implementation guidance rules, see TaskPoolScheduler.cs
+                        // in System.Reactive.PlatformServices\Reactive\Concurrency.
+                        //
+                        var timer = new DispatcherTimer
+                        {
+                            Interval = TimeSpan.Zero
+                        };
+                        timer.Tick += (o, e) =>
+                        {
+                            timer.Stop();
+                            ExceptionDispatchInfo.Capture(ex).Throw();
+                        };
+
+                        timer.Start();
+                    }
+                }
+            });
+
+            return StableCompositeDisposable.Create(
+                d,
+                Disposable.Create(res, _ => _.Cancel())
+            );
+        }
+
+        /// <summary>
+        /// Schedules an action to be executed after <paramref name="dueTime"/> on the dispatcher, using a <see cref="DispatcherTimer"/> object.
+        /// </summary>
+        /// <typeparam name="TState">The type of the state passed to the scheduled action.</typeparam>
+        /// <param name="state">State passed to the action to be executed.</param>
+        /// <param name="action">Action to be executed.</param>
+        /// <param name="dueTime">Relative time after which to execute the action.</param>
+        /// <returns>The disposable object used to cancel the scheduled action (best effort).</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="action"/> is <c>null</c>.</exception>
+        public override IDisposable Schedule<TState>(TState state, TimeSpan dueTime, Func<IScheduler, TState, IDisposable> action)
+        {
+            if (action == null)
+            {
+                throw new ArgumentNullException(nameof(action));
+            }
+
+            var dt = Scheduler.Normalize(dueTime);
+            if (dt.Ticks == 0)
+            {
+                return Schedule(state, action);
+            }
+
+            return ScheduleSlow(state, dt, action);
+        }
+
+        private IDisposable ScheduleSlow<TState>(TState state, TimeSpan dueTime, Func<IScheduler, TState, IDisposable> action)
+        {
+            var d = new MultipleAssignmentDisposable();
+
+            var timer = new DispatcherTimer();
+
+            timer.Tick += (o, e) =>
+            {
+                var t = Interlocked.Exchange(ref timer, null);
+                if (t != null)
+                {
+                    try
+                    {
+                        d.Disposable = action(this, state);
+                    }
+                    finally
+                    {
+                        t.Stop();
+                        action = null;
+                    }
+                }
+            };
+
+            timer.Interval = dueTime;
+            timer.Start();
+
+            d.Disposable = Disposable.Create(() =>
+            {
+                var t = Interlocked.Exchange(ref timer, null);
+                if (t != null)
+                {
+                    t.Stop();
+                    action = (_, __) => Disposable.Empty;
+                }
+            });
+
+            return d;
+        }
+
+        /// <summary>
+        /// Schedules a periodic piece of work on the dispatcher, using a <see cref="DispatcherTimer"/> object.
+        /// </summary>
+        /// <typeparam name="TState">The type of the state passed to the scheduled action.</typeparam>
+        /// <param name="state">Initial state passed to the action upon the first iteration.</param>
+        /// <param name="period">Period for running the work periodically.</param>
+        /// <param name="action">Action to be executed, potentially updating the state.</param>
+        /// <returns>The disposable object used to cancel the scheduled recurring action (best effort).</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="action"/> is <c>null</c>.</exception>
+        /// <exception cref="ArgumentOutOfRangeException"><paramref name="period"/> is less than <see cref="TimeSpan.Zero"/>.</exception>
+        public IDisposable SchedulePeriodic<TState>(TState state, TimeSpan period, Func<TState, TState> action)
+        {
+            //
+            // According to MSDN documentation, the default is TimeSpan.Zero, so that's definitely valid.
+            // Empirical observation - negative values seem to be normalized to TimeSpan.Zero, but let's not go there.
+            //
+            if (period < TimeSpan.Zero)
+            {
+                throw new ArgumentOutOfRangeException(nameof(period));
+            }
+
+            if (action == null)
+            {
+                throw new ArgumentNullException(nameof(action));
+            }
+
+            var timer = new DispatcherTimer();
+
+            var state1 = state;
+
+            timer.Tick += (o, e) =>
+            {
+                state1 = action(state1);
+            };
+
+            timer.Interval = period;
+            timer.Start();
+
+            return Disposable.Create(() =>
+            {
+                var t = Interlocked.Exchange(ref timer, null);
+                if (t != null)
+                {
+                    t.Stop();
+                    action = _ => _;
+                }
+            });
+        }
+    }
+}

src/ReactiveUI.Uno/PlatformRegistrations.cs

@@ -0,0 +1,42 @@
+// Copyright (c) 2019 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using System;
+using System.Reactive.Concurrency;
+using System.Reactive.PlatformServices;
+
+namespace ReactiveUI
+{
+    /// <summary>
+    /// UWP platform registrations.
+    /// </summary>
+    /// <seealso cref="ReactiveUI.IWantsToRegisterStuff" />
+    public class PlatformRegistrations : IWantsToRegisterStuff
+    {
+        /// <inheritdoc/>
+        public void Register(Action<Func<object>, Type> registerFunction)
+        {
+            registerFunction(() => new PlatformOperations(), typeof(IPlatformOperations));
+            registerFunction(() => new ActivationForViewFetcher(), typeof(IActivationForViewFetcher));
+            registerFunction(() => new DependencyObjectObservableForProperty(), typeof(ICreatesObservableForProperty));
+            registerFunction(() => new BooleanToVisibilityTypeConverter(), typeof(IBindingTypeConverter));
+            registerFunction(() => new AutoDataTemplateBindingHook(), typeof(IPropertyBindingHook));
+            registerFunction(() => new WinRTAppDataDriver(), typeof(ISuspensionDriver));
+
+#if NETSTANDARD
+            if (WasmPlatformEnlightenmentProvider.IsWasm)
+            {
+                RxApp.TaskpoolScheduler = WasmScheduler.Default;
+                RxApp.MainThreadScheduler = WasmScheduler.Default;
+            }
+            else
+#endif
+            {
+                RxApp.TaskpoolScheduler = TaskPoolScheduler.Default;
+                RxApp.MainThreadScheduler = new WaitForDispatcherScheduler(() => CoreDispatcherScheduler.Current);
+            }
+        }
+    }
+}