Add a desktop shell capability, tray icons and hidden mounts

apps/archive-tool/generated/RustViewRegistry.g.cs

@@ -16,6 +16,11 @@ internal static class RustViewRegistry
         _ => throw new global::System.ArgumentOutOfRangeException(nameof(viewId)),
     };
 
+    internal static IDisposable CreateTray(int trayId, IAvnRustViewModel model) => trayId switch
+    {
+        _ => throw new global::System.ArgumentOutOfRangeException(nameof(trayId)),
+    };
+
     private static TWindow CreateDynamic<TWindow>(
         IAvnRustViewModel model,
         RustViewModelDescriptor descriptor)

apps/archive-tool/generated/generated_view_models.rs

@@ -375,6 +375,7 @@ impl<T: MainViewModel> crate::view_model::DynamicViewModel for MainViewModelDisp
 }
 
 pub fn mount_main_window(scope: &crate::AppScope, model: impl MainViewModel) -> crate::Result<()> { scope.mount_dynamic_view_model(1, MainViewModelDispatch { model }) }
+pub fn mount_main_window_hidden(scope: &crate::AppScope, model: impl MainViewModel) -> crate::Result<()> { scope.mount_dynamic_view_model_hidden(1, MainViewModelDispatch { model }).map(drop) }
 
 #[derive(Clone, Debug)]
 pub struct EntryRowViewModelSink(crate::view_model::ViewModelSink);

apps/hash-calculator/generated/RustViewRegistry.g.cs

@@ -16,6 +16,11 @@ internal static class RustViewRegistry
         _ => throw new global::System.ArgumentOutOfRangeException(nameof(viewId)),
     };
 
+    internal static IDisposable CreateTray(int trayId, IAvnRustViewModel model) => trayId switch
+    {
+        _ => throw new global::System.ArgumentOutOfRangeException(nameof(trayId)),
+    };
+
     private static TWindow CreateDynamic<TWindow>(
         IAvnRustViewModel model,
         RustViewModelDescriptor descriptor)

apps/hash-calculator/generated/generated_view_models.rs

@@ -203,6 +203,7 @@ impl<T: MainViewModel> crate::view_model::DynamicViewModel for MainViewModelDisp
 }
 
 pub fn mount_main_window(scope: &crate::AppScope, model: impl MainViewModel) -> crate::Result<()> { scope.mount_dynamic_view_model(1, MainViewModelDispatch { model }) }
+pub fn mount_main_window_hidden(scope: &crate::AppScope, model: impl MainViewModel) -> crate::Result<()> { scope.mount_dynamic_view_model_hidden(1, MainViewModelDispatch { model }).map(drop) }
 
 #[derive(Clone, Debug)]
 pub struct FileRowViewModelSink(crate::view_model::ViewModelSink);

apps/pdf-viewer/generated/RustViewRegistry.g.cs

@@ -16,6 +16,11 @@ internal static class RustViewRegistry
         _ => throw new global::System.ArgumentOutOfRangeException(nameof(viewId)),
     };
 
+    internal static IDisposable CreateTray(int trayId, IAvnRustViewModel model) => trayId switch
+    {
+        _ => throw new global::System.ArgumentOutOfRangeException(nameof(trayId)),
+    };
+
     private static TWindow CreateDynamic<TWindow>(
         IAvnRustViewModel model,
         RustViewModelDescriptor descriptor)

apps/pdf-viewer/generated/generated_view_models.rs

@@ -217,6 +217,7 @@ impl<T: MainViewModel> crate::view_model::DynamicViewModel for MainViewModelDisp
 }
 
 pub fn mount_main_window(scope: &crate::AppScope, model: impl MainViewModel) -> crate::Result<()> { scope.mount_dynamic_view_model(1, MainViewModelDispatch { model }) }
+pub fn mount_main_window_hidden(scope: &crate::AppScope, model: impl MainViewModel) -> crate::Result<()> { scope.mount_dynamic_view_model_hidden(1, MainViewModelDispatch { model }).map(drop) }
 
 #[derive(Clone, Debug)]
 pub struct OutlineItemViewModelSink(crate::view_model::ViewModelSink);

apps/system-monitor/GeneratedHostRegistry/RustViewRegistry.g.cs

@@ -16,6 +16,11 @@ internal static class RustViewRegistry
         _ => throw new global::System.ArgumentOutOfRangeException(nameof(viewId)),
     };
 
+    internal static IDisposable CreateTray(int trayId, IAvnRustViewModel model) => trayId switch
+    {
+        _ => throw new global::System.ArgumentOutOfRangeException(nameof(trayId)),
+    };
+
     private static TWindow CreateDynamic<TWindow>(
         IAvnRustViewModel model,
         RustViewModelDescriptor descriptor)

apps/system-monitor/generated_view_models.rs

@@ -704,6 +704,7 @@ impl<T: MainViewModel> crate::view_model::DynamicViewModel for MainViewModelDisp
 }
 
 pub fn mount_main_window(scope: &crate::AppScope, model: impl MainViewModel) -> crate::Result<()> { scope.mount_dynamic_view_model(1, MainViewModelDispatch { model }) }
+pub fn mount_main_window_hidden(scope: &crate::AppScope, model: impl MainViewModel) -> crate::Result<()> { scope.mount_dynamic_view_model_hidden(1, MainViewModelDispatch { model }).map(drop) }
 
 #[derive(Clone, Debug)]
 pub struct ProcessRowViewModelSink(crate::view_model::ViewModelSink);

host/Com/AvnApplication.Shell.cs

@@ -0,0 +1,134 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using Avalonia.Controls;
+using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Host.Generated.ViewModels;
+using Avalonia.Rust.Interop;
+using Avalonia.Threading;
+
+namespace Avalonia.Host.Com;
+
+/// <summary>
+/// Stage 33 desktop shell integration: the shutdown mode, tray icons and
+/// window-level settings. Avalonia's own <c>ShutdownMode</c>, <c>TrayIcon</c>,
+/// <c>Topmost</c> and <c>TransparencyLevelHint</c> do the work; only the
+/// capture exclusion calls the platform directly, because Avalonia has no
+/// equivalent.
+/// </summary>
+public partial class AvnApplication : IAvnApplication6
+{
+    private ShutdownMode _shutdownMode = ShutdownMode.OnLastWindowClose;
+    private readonly List<IDisposable> _trays = new();
+
+    public int SetShutdownMode(int mode)
+    {
+        if (mode is < (int)ShutdownMode.OnLastWindowClose or > (int)ShutdownMode.OnExplicitShutdown)
+            return HResults.E_INVALIDARG;
+        try
+        {
+            _shutdownMode = (ShutdownMode)mode;
+            if (_lifetime is { } lifetime)
+                lifetime.ShutdownMode = _shutdownMode;
+            return HResults.S_OK;
+        }
+        catch (Exception e)
+        {
+            return AbiError.Capture(e);
+        }
+    }
+
+    public int CreateRustVmTray(int trayId, IAvnRustViewModel? model)
+    {
+        if (model is null)
+            return HResults.E_POINTER;
+        try
+        {
+            Dispatcher.UIThread.VerifyAccess();
+            _trays.Add(RustViewRegistry.CreateTray(trayId, model));
+            return HResults.S_OK;
+        }
+        catch (Exception e)
+        {
+            return AbiError.Capture(e);
+        }
+    }
+
+    public int GetPlatformHandle(IAvnWindow? window, out long handle)
+    {
+        long found = 0;
+        var hr = WithWindow(window, managed => found = managed.TryGetPlatformHandle()?.Handle ?? 0);
+        handle = found;
+        return hr;
+    }
+
+    public int SetWindowTopmost(IAvnWindow? window, int topmost) =>
+        WithWindow(window, managed => managed.Topmost = topmost != 0);
+
+    public int SetWindowTransparent(IAvnWindow? window, int transparent) =>
+        WithWindow(window, managed => managed.TransparencyLevelHint = transparent != 0
+            ? [WindowTransparencyLevel.Transparent]
+            : []);
+
+    public int SetWindowExcludedFromCapture(IAvnWindow? window, int excluded)
+    {
+        if (!OperatingSystem.IsWindows())
+            return HResults.E_NOTIMPL;
+        var result = 0;
+        var hr = WithWindow(window, managed =>
+        {
+            var hwnd = managed.TryGetPlatformHandle()?.Handle ?? 0;
+            if (hwnd == 0)
+                throw new InvalidOperationException("The window has no native handle yet; show it first.");
+            if (!Win32.SetWindowDisplayAffinity(hwnd, excluded != 0 ? Win32.WDA_EXCLUDEFROMCAPTURE : Win32.WDA_NONE))
+                result = Marshal.GetHRForLastWin32Error();
+        });
+        return hr < 0 ? hr : result;
+    }
+
+    /// <summary>Runs <paramref name="action"/> on the managed window, on the UI thread.</summary>
+    private static int WithWindow(IAvnWindow? window, Action<Window> action)
+    {
+        if (window is null)
+            return HResults.E_POINTER;
+        try
+        {
+            Dispatcher.UIThread.VerifyAccess();
+            var managed = (Window?)ProjectionRuntime.Unwrap(window)
+                ?? throw new ObjectDisposedException(nameof(window));
+            action(managed);
+            return HResults.S_OK;
+        }
+        catch (Exception e)
+        {
+            return AbiError.Capture(e);
+        }
+    }
+
+    /// <summary>Removes the tray icons; Avalonia also disposes them as the dispatcher shuts down.</summary>
+    private void ReleaseTrays()
+    {
+        foreach (var tray in _trays)
+        {
+            try
+            {
+                tray.Dispose();
+            }
+            catch (Exception)
+            {
+                // Shutdown keeps going; the platform removes the icon with the process.
+            }
+        }
+        _trays.Clear();
+    }
+
+    private static partial class Win32
+    {
+        public const uint WDA_NONE = 0x00;
+        public const uint WDA_EXCLUDEFROMCAPTURE = 0x11;
+
+        [LibraryImport("user32.dll", SetLastError = true)]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        public static partial bool SetWindowDisplayAffinity(nint hwnd, uint affinity);
+    }
+}

host/Com/AvnApplication.cs

@@ -34,7 +34,8 @@ public int Run(IAvnAppHandler? handler)
             var startupArguments = SnapshotStartupArguments();
             var lifetime = new ClassicDesktopStyleApplicationLifetime
             {
-                ShutdownMode = ShutdownMode.OnLastWindowClose,
+                // OnLastWindowClose unless IAvnApplication6.SetShutdownMode said otherwise.
+                ShutdownMode = _shutdownMode,
                 Args = startupArguments,
             };
             _lifetime = lifetime;
@@ -58,6 +59,7 @@ public int Run(IAvnAppHandler? handler)
         }
         finally
         {
+            ReleaseTrays();
             ReleaseDesktopFileIntegration();
         }
     }

host/Com/AvnGuids.cs

@@ -32,4 +32,9 @@ internal static class AvnGuids
     // the completion rides the shared async operation registry, and nothing below
     // is added to a published vtable.
     public const string IAvnApplication5 = "6B2E8F10-4C91-4E3A-9A77-1F0C2B3A4D70";
+
+    // Stage 33 desktop shell integration: shutdown mode, tray icons and the
+    // window-level settings a capture tool needs. Another separately versioned
+    // capability; nothing below is added to a published vtable.
+    public const string IAvnApplication6 = "6B2E8F10-4C91-4E3A-9A77-1F0C2B3A4D80";
 }