feat(diags): Add ability for a diag view to send notifications

src/Uno.Foundation/Diagnostics/DiagnosticViewNotification.cs

@@ -0,0 +1,29 @@
+#nullable enable
+using System;
+using System.ComponentModel;
+using System.Linq;
+
+namespace Uno.Diagnostics.UI;
+
+/// <summary>
+/// A notification sent by a diagnostic view to visually show an important status.
+/// </summary>
+/// <param name="content">The content of the notification.</param>
+/// <param name="duration">Configures the duration to wait before automatically hide the notification.</param>
+public class DiagnosticViewNotification(object content, TimeSpan? duration = null)
+{
+	[EditorBrowsable(EditorBrowsableState.Never)] // For XAML only
+	public DiagnosticViewNotification() : this(default!)
+	{
+	}
+
+	/// <summary>
+	/// The content of the notification.
+	/// </summary>
+	public object Content { get; set; } = content;
+
+	/// <summary>
+	/// Configures the duration to wait before automatically hide the notification.
+	/// </summary>
+	public TimeSpan? Duration { get; set; } = duration;
+}

src/Uno.Foundation/Diagnostics/DiagnosticViewRegistry.cs

@@ -20,21 +20,21 @@ internal static class DiagnosticViewRegistry
 	internal static IImmutableList<DiagnosticViewRegistration> Registrations => _registrations;
 
 	/// <summary>
-	/// Register a global diagnostic provider that can be displayed on any window.
+	/// Register a global diagnostic view that can be displayed on any window.
 	/// </summary>
-	/// <param name="provider">A diagnostic provider to display.</param>
-	public static void Register(IDiagnosticViewProvider provider)
+	/// <param name="view">A diagnostic view to display.</param>
+	public static void Register(IDiagnosticView view)
 	{
 		ImmutableInterlocked.Update(
 			ref _registrations,
 			static (providers, provider) => providers.Add(provider),
-			new DiagnosticViewRegistration(DiagnosticViewRegistrationMode.One, provider));
+			new DiagnosticViewRegistration(DiagnosticViewRegistrationMode.One, view));
 
 		Added?.Invoke(null, _registrations);
 	}
 }
 
-internal record DiagnosticViewRegistration(DiagnosticViewRegistrationMode Mode, IDiagnosticViewProvider Provider);
+internal record DiagnosticViewRegistration(DiagnosticViewRegistrationMode Mode, IDiagnosticView Provider);
 
 internal enum DiagnosticViewRegistrationMode
 {

src/Uno.Foundation/Diagnostics/IDiagnosticViewProvider.cs → src/Uno.Foundation/Diagnostics/IDiagnosticView.cs

@@ -9,20 +9,25 @@ namespace Uno.Diagnostics.UI;
 /// <summary>
 /// A diagnostic entry that can be displayed by the DiagnosticsOverlay.
 /// </summary>
-public interface IDiagnosticViewProvider
+public interface IDiagnosticView
 {
+	/// <summary>
+	/// Identifier of the diagnostic view than can be used to request to show or remove it from a DiagnosticsOverlay.
+	/// </summary>
+	string Id { get; }
+
 	/// <summary>
 	/// Friendly name of the diagnostic.
 	/// </summary>
 	string Name { get; }
 
 	/// <summary>
-	/// Get a preview of the diagnostic, usually a value or an icon.
+	/// Gets a visual element of the diagnostic, usually a value or an icon.
 	/// </summary>
 	/// <param name="context">An update coordinator that can be used to push updates on the preview.</param>
 	/// <returns>Either a UIElement to be displayed by the diagnostic overlay or a plain object (rendered as text).</returns>
 	/// <remarks>This is expected to be invoked on the dispatcher used to render the preview.</remarks>
-	object GetPreview(IDiagnosticViewContext context);
+	object GetElement(IDiagnosticViewContext context);
 
 	/// <summary>
 	/// Show details of the diagnostic.

src/Uno.Foundation/Diagnostics/IDiagnosticViewContext.cs

@@ -19,4 +19,6 @@ public interface IDiagnosticViewContext
 	void ScheduleRecurrent(Action action);
 
 	void AbortRecurrent(Action action);
+
+	void Notify(DiagnosticViewNotification notification);
 }

src/Uno.UI.RemoteControl/HotReload/ClientHotReloadProcessor.Common.Status.cs

@@ -48,7 +48,7 @@ internal record Status(
 
 	private class StatusSink
 	{
-		private readonly DiagnosticView<HotReloadStatusView, Status> _view = DiagnosticView.Register<HotReloadStatusView, Status>("Hot reload", (view, status) => view.Update(status));
+		private readonly DiagnosticView<HotReloadStatusView, Status> _view = DiagnosticView.Register<HotReloadStatusView, Status>("Hot reload", ctx => new HotReloadStatusView(ctx), static (view, status) => view.Update(status));
 
 		private HotReloadState? _serverState;
 		private ImmutableDictionary<long, HotReloadServerOperationData> _serverOperations = ImmutableDictionary<long, HotReloadServerOperationData>.Empty;

src/Uno.UI.RemoteControl/HotReload/ClientHotReloadProcessor.MetadataUpdate.cs

@@ -88,7 +88,7 @@ private static void ShowDiagnosticsOnFirstActivation(object snd, WindowActivated
 		if (snd is Window { RootElement.XamlRoot: { } xamlRoot } window)
 		{
 			window.Activated -= ShowDiagnosticsOnFirstActivation;
-			DiagnosticsOverlay.Get(xamlRoot).IsVisible = true;
+			DiagnosticsOverlay.Get(xamlRoot).Show();
 		}
 	}
 

src/Uno.UI.RemoteControl/HotReload/HotReloadStatusView.cs

@@ -1,20 +1,45 @@
-using System;
+#nullable enable
+
+using System;
 using System.Collections.ObjectModel;
 using System.ComponentModel;
 using System.Globalization;
-using System.IO;
 using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
 using Windows.UI;
 using Microsoft.UI;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
+using Microsoft.UI.Xaml.Media;
+using Microsoft.UI.Xaml.Shapes;
+using Uno.Diagnostics.UI;
 using Uno.UI.RemoteControl.HotReload.Messages;
 using static Uno.UI.RemoteControl.HotReload.ClientHotReloadProcessor;
+using Path = System.IO.Path;
 
 namespace Uno.UI.RemoteControl.HotReload;
 
+[TemplateVisualState(GroupName = "Status", Name = StatusUnknownVisualStateName)]
+[TemplateVisualState(GroupName = "Status", Name = StatusErrorVisualStateName)]
+[TemplateVisualState(GroupName = "Status", Name = StatusInitializingVisualStateName)]
+[TemplateVisualState(GroupName = "Status", Name = StatusIdleVisualStateName)]
+[TemplateVisualState(GroupName = "Status", Name = StatusProcessingVisualStateName)]
+[TemplateVisualState(GroupName = "Result", Name = ResultNoneVisualStateName)]
+[TemplateVisualState(GroupName = "Result", Name = ResultSuccessVisualStateName)]
+[TemplateVisualState(GroupName = "Result", Name = ResultFailedVisualStateName)]
 internal sealed partial class HotReloadStatusView : Control
 {
+	private const string StatusUnknownVisualStateName = "Unknown";
+	private const string StatusErrorVisualStateName = "Error";
+	private const string StatusInitializingVisualStateName = "Initializing";
+	private const string StatusIdleVisualStateName = "Idle";
+	private const string StatusProcessingVisualStateName = "Processing";
+
+	private const string ResultNoneVisualStateName = "None";
+	private const string ResultSuccessVisualStateName = "Success";
+	private const string ResultFailedVisualStateName = "Failed";
+
 	#region HeadLine (DP)
 	public static DependencyProperty HeadLineProperty { get; } = DependencyProperty.Register(
 		nameof(HeadLine),
@@ -43,8 +68,40 @@ public ObservableCollection<HotReloadEntryViewModel> History
 	}
 	#endregion
 
-	public HotReloadStatusView()
+	#region SuccessNotification (DP)
+	public static readonly DependencyProperty SuccessNotificationProperty = DependencyProperty.Register(
+		nameof(SuccessNotification),
+		typeof(DiagnosticViewNotification),
+		typeof(HotReloadStatusView),
+		new PropertyMetadata(default(DiagnosticViewNotification?)));
+
+	public DiagnosticViewNotification? SuccessNotification
+	{
+		get => (DiagnosticViewNotification?)GetValue(SuccessNotificationProperty);
+		set => SetValue(SuccessNotificationProperty, value);
+	}
+	#endregion
+
+	#region FailureNotification (DP)
+	public static readonly DependencyProperty FailureNotificationProperty = DependencyProperty.Register(
+		nameof(FailureNotification),
+		typeof(DiagnosticViewNotification),
+		typeof(HotReloadStatusView),
+		new PropertyMetadata(default(DiagnosticViewNotification?)));
+
+	public DiagnosticViewNotification? FailureNotification
+	{
+		get => (DiagnosticViewNotification?)GetValue(FailureNotificationProperty);
+		set => SetValue(FailureNotificationProperty, value);
+	}
+	#endregion
+
+	private readonly IDiagnosticViewContext _ctx;
+	private string _resultState = "None";
+
+	public HotReloadStatusView(IDiagnosticViewContext ctx)
 	{
+		_ctx = ctx;
 		DefaultStyleKey = typeof(HotReloadStatusView);
 		History = [];
 
@@ -57,7 +114,23 @@ public void Update(Status status)
 		UpdateHeadline(status.State);
 
 		VisualStateManager.GoToState(this, GetStatusVisualState(status.State), true);
-		VisualStateManager.GoToState(this, GetResultVisualState(), true);
+
+		var resultState = GetResultVisualState();
+		if (resultState != _resultState)
+		{
+			_resultState = resultState;
+			VisualStateManager.GoToState(this, resultState, true);
+			switch (resultState)
+			{
+				case ResultSuccessVisualStateName when SuccessNotification is not null:
+					_ctx.Notify(SuccessNotification);
+					break;
+
+				case ResultFailedVisualStateName when FailureNotification is not null:
+					_ctx.Notify(FailureNotification);
+					break;
+			}
+		}
 	}
 
 	private void SyncOperations(Status status)
@@ -156,22 +229,24 @@ State of the hot-reload engine is unknown.
 	private static string GetStatusVisualState(HotReloadState state)
 		=> state switch
 		{
-			HotReloadState.Disabled => "Disabled",
-			HotReloadState.Initializing => "Initializing",
-			HotReloadState.Idle => "Idle",
-			HotReloadState.Processing => "Processing",
-			_ => "Unknown"
+			HotReloadState.Disabled => StatusErrorVisualStateName,
+			HotReloadState.Initializing => StatusInitializingVisualStateName,
+			HotReloadState.Idle => StatusIdleVisualStateName,
+			HotReloadState.Processing => StatusProcessingVisualStateName,
+			_ => StatusUnknownVisualStateName
 		};
 
 	private string GetResultVisualState()
 	{
 		var operations = History;
 		if (operations is { Count: 0 } || operations.Any(op => !op.IsCompleted))
 		{
-			return "None"; // Makes sure to restore to previous None!
+			return ResultNoneVisualStateName; // Makes sure to restore to previous None!
 		}
 
-		return operations[0].IsSuccess ? "Success" : "Failed";
+		return operations[0].IsSuccess
+			? ResultSuccessVisualStateName
+			: ResultFailedVisualStateName;
 	}
 }
 

src/Uno.UI.RemoteControl/HotReload/HotReloadStatusView.xaml

@@ -2,6 +2,7 @@
 	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 	xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 	xmlns:local="using:Uno.UI.RemoteControl.HotReload"
+	xmlns:diag="using:Uno.Diagnostics.UI"
 	xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
 	xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 	xmlns:mux="using:Microsoft.UI.Xaml.Controls"
@@ -23,6 +24,26 @@
 	</DataTemplate>
 
 	<Style TargetType="local:HotReloadStatusView">
+		<Setter Property="SuccessNotification">
+			<Setter.Value>
+				<diag:DiagnosticViewNotification Duration="0:0:10">
+					<diag:DiagnosticViewNotification.Content>
+						<Ellipse Width="16" Height="16" Fill="Green" />
+					</diag:DiagnosticViewNotification.Content>
+				</diag:DiagnosticViewNotification>
+			</Setter.Value>
+		</Setter>
+
+		<Setter Property="FailureNotification">
+			<Setter.Value>
+				<diag:DiagnosticViewNotification Duration="0:0:0">
+					<diag:DiagnosticViewNotification.Content>
+						<Ellipse Width="16" Height="16" Fill="Red" />
+					</diag:DiagnosticViewNotification.Content>
+				</diag:DiagnosticViewNotification>
+			</Setter.Value>
+		</Setter>
+
 		<Setter Property="Template">
 			<Setter.Value>
 				<ControlTemplate TargetType="local:HotReloadStatusView">
@@ -34,7 +55,7 @@
 										<Setter Target="Dot.Fill" Value="Gray" />
 									</VisualState.Setters>
 								</VisualState>
-								<VisualState x:Name="Disabled">
+								<VisualState x:Name="Error">
 									<VisualState.Setters>
 										<Setter Target="Dot.Fill" Value="Red" />
 									</VisualState.Setters>

src/Uno.UI.Toolkit/Diagnostics/DiagnosticCounter.cs

@@ -9,11 +9,13 @@
 
 namespace Uno.Diagnostics.UI;
 
-internal sealed class DiagnosticCounter(string name, string description) : IDiagnosticViewProvider
+internal sealed class DiagnosticCounter(string name, string description) : IDiagnosticView
 {
-	private DiagnosticViewHelper<TextBlock>? _preview;
+	private DiagnosticViewManager<TextBlock>? _preview;
 	private long _value;
 
+	public string Id => name;
+
 	public string Name => name;
 
 	public string Description => description;
@@ -32,10 +34,10 @@ public void Decrement()
 		_preview?.NotifyChanged();
 	}
 
-	object IDiagnosticViewProvider.GetPreview(IDiagnosticViewContext context)
+	object IDiagnosticView.GetElement(IDiagnosticViewContext context)
 		=> (_preview ??= DiagnosticViewHelper.CreateText(() => _value)).GetView(context);
 
-	ValueTask<object?> IDiagnosticViewProvider.GetDetailsAsync(IDiagnosticViewContext context, CancellationToken ct)
+	ValueTask<object?> IDiagnosticView.GetDetailsAsync(IDiagnosticViewContext context, CancellationToken ct)
 		=> new($"current: {_value}\r\n\r\n{Description}");
 }
 #endif

src/Uno.UI.Toolkit/Diagnostics/DiagnosticsOverlay.DiagnosticElement.cs

@@ -14,7 +14,7 @@ namespace Uno.Diagnostics.UI;
 
 public sealed partial class DiagnosticsOverlay
 {
-	private record DiagnosticElement(DiagnosticsOverlay Overlay, IDiagnosticViewProvider Provider, IDiagnosticViewContext Coordinator) : IDisposable
+	private record DiagnosticElement(DiagnosticsOverlay Overlay, IDiagnosticView Provider, IDiagnosticViewContext Context) : IDisposable
 	{
 		private UIElement? _preview;
 		private CancellationTokenSource? _details;
@@ -25,7 +25,7 @@ private UIElement CreatePreview()
 		{
 			try
 			{
-				var preview = Provider.GetPreview(Coordinator);
+				var preview = Provider.GetElement(Context);
 				var element = preview as UIElement ?? DiagnosticViewHelper.CreateText(preview.ToString());
 
 				if (ToolTipService.GetToolTip(element) is null)
@@ -59,9 +59,12 @@ async ValueTask Do()
 				try
 				{
 					var ct = new CancellationTokenSource();
-					Interlocked.Exchange(ref _details, ct)?.Cancel();
+					if (Interlocked.Exchange(ref _details, ct) is { IsCancellationRequested: false } previous)
+					{
+						await previous.CancelAsync();
+					}
 
-					var details = await Provider.GetDetailsAsync(Coordinator, ct.Token);
+					var details = await Provider.GetDetailsAsync(Context, ct.Token);
 					switch (details)
 					{
 						case null: