Refactor WASM input and dom-callbacks to work with multithreading

src/Browser/Avalonia.Browser/BrowserActivatableLifetime.cs

@@ -1,36 +1,25 @@
-using System;
 using Avalonia.Browser.Interop;
 using Avalonia.Controls.ApplicationLifetimes;
-using Avalonia.Threading;
 
 namespace Avalonia.Browser;
 
-internal class BrowserActivatableLifetime : IActivatableLifetime
+internal class BrowserActivatableLifetime : ActivatableLifetimeBase
 {
     public BrowserActivatableLifetime()
     {
-        bool? initiallyVisible = InputHelper.SubscribeVisibilityChange(visible =>
+        OnVisibilityStateChanged(DomHelper.GetCurrentDocumentVisibility(), true);
+    }
+
+    public void OnVisibilityStateChanged(string visibilityState, bool initial = false)
+    {
+        var visible = visibilityState == "visible";
+        if (visible)
         {
-            initiallyVisible = null;
-            (visible ? Activated : Deactivated)?.Invoke(this, new ActivatedEventArgs(ActivationKind.Background));
-        });
-
-        // Trigger Activated as an initial state, if web page is visible, and wasn't hidden during initialization.
-        if (initiallyVisible == true)
+            OnActivated(ActivationKind.Background);
+        }
+        else if (!initial)
         {
-            _ = Dispatcher.UIThread.InvokeAsync(() =>
-            {
-                if (initiallyVisible == true)
-                {
-                    Activated?.Invoke(this, new ActivatedEventArgs(ActivationKind.Background));
-                }
-            }, DispatcherPriority.Background);
+            OnDeactivated(ActivationKind.Background);
         }
     }
-
-    public event EventHandler<ActivatedEventArgs>? Activated;
-    public event EventHandler<ActivatedEventArgs>? Deactivated;
-
-    public bool TryLeaveBackground() => false;
-    public bool TryEnterBackground() => false;
 }

src/Browser/Avalonia.Browser/BrowserInputHandler.cs

@@ -22,7 +22,7 @@ internal class BrowserInputHandler
 
     private static readonly PooledList<RawPointerPoint> s_intermediatePointsPooledList = new(ClearMode.Never);
 
-    public BrowserInputHandler(BrowserTopLevelImpl topLevelImpl, JSObject container)
+    public BrowserInputHandler(BrowserTopLevelImpl topLevelImpl, JSObject container, JSObject inputElement, int topLevelId)
     {
         _topLevelImpl = topLevelImpl;
         _container = container ?? throw new ArgumentNullException(nameof(container));
@@ -32,40 +32,36 @@ public BrowserInputHandler(BrowserTopLevelImpl topLevelImpl, JSObject container)
         _wheelMouseDevice = new MouseDevice();
         _mouseDevices = new();
 
-        InputHelper.SubscribeKeyEvents(
-            container,
-            OnKeyDown,
-            OnKeyUp);
-        InputHelper.SubscribePointerEvents(container, OnPointerMove, OnPointerDown, OnPointerUp,
-            OnPointerCancel, OnWheel);
-        InputHelper.SubscribeDropEvents(container, OnDragEvent);
+        TextInputMethod = new BrowserTextInputMethod(this, container, inputElement);
+        InputPane = new BrowserInputPane();
+
+        InputHelper.SubscribeInputEvents(container, topLevelId);
     }
 
+    public BrowserTextInputMethod TextInputMethod { get; }
+    public BrowserInputPane InputPane { get; }
+
     public ulong Timestamp => (ulong)_sw.ElapsedMilliseconds;
 
     internal void SetInputRoot(IInputRoot inputRoot)
     {
         _inputRoot = inputRoot;
     }
 
-    private static RawPointerPoint ExtractRawPointerFromJsArgs(JSObject args)
+    private static RawPointerPoint CreateRawPointer(double offsetX, double offsetY,
+        double pressure, double tiltX, double tiltY, double twist) => new()
     {
-        var point = new RawPointerPoint
-        {
-            Position = new Point(args.GetPropertyAsDouble("offsetX"), args.GetPropertyAsDouble("offsetY")),
-            Pressure = (float)args.GetPropertyAsDouble("pressure"),
-            XTilt = (float)args.GetPropertyAsDouble("tiltX"),
-            YTilt = (float)args.GetPropertyAsDouble("tiltY"),
-            Twist = (float)args.GetPropertyAsDouble("twist")
-        };
-
-        return point;
-    }
-
-    private bool OnPointerMove(JSObject args)
+        Position = new Point(offsetX, offsetY),
+        Pressure = (float)pressure,
+        XTilt = (float)tiltX,
+        YTilt = (float)tiltY,
+        Twist = (float)twist
+    };
+
+    public bool OnPointerMove(string pointerType, long pointerId, double offsetX, double offsetY,
+        double pressure, double tiltX, double tiltY, double twist, int modifier, JSObject argsObj)
     {
-        var pointerType = args.GetPropertyAsString("pointerType");
-        var point = ExtractRawPointerFromJsArgs(args);
+        var point = CreateRawPointer(offsetX, offsetY, pressure, tiltX, tiltY, twist);
         var type = pointerType switch
         {
             "touch" => RawPointerEventType.TouchUpdate,
@@ -74,31 +70,36 @@ private bool OnPointerMove(JSObject args)
 
         var coalescedEvents = new Lazy<IReadOnlyList<RawPointerPoint>?>(() =>
         {
-            var points = InputHelper.GetCoalescedEvents(args);
+            // To minimize JS interop usage, we resolve all points properties in a single call.
+            var pointsProps = InputHelper.GetCoalescedEvents(argsObj);
+            var pointsCount = pointsProps.Length / 6;
+            argsObj.Dispose();
             s_intermediatePointsPooledList.Clear();
-            s_intermediatePointsPooledList.Capacity = points.Length - 1;
+            s_intermediatePointsPooledList.Capacity = pointsCount - 1;
 
             // Skip the last one, as it is already processed point.
-            for (var i = 0; i < points.Length - 1; i++)
+            for (var i = 0; i < pointsCount - 1; i++)
             {
-                var point = points[i];
-                s_intermediatePointsPooledList.Add(ExtractRawPointerFromJsArgs(point));
+                s_intermediatePointsPooledList.Add(CreateRawPointer(
+                    pointsProps[i], pointsProps[i + 1],
+                    pointsProps[i + 2], pointsProps[i + 3],
+                    pointsProps[i + 4], pointsProps[i + 5]));
             }
 
             return s_intermediatePointsPooledList;
         });
 
-        return RawPointerEvent(type, pointerType!, point, GetModifiers(args), args.GetPropertyAsInt32("pointerId"),
+        return RawPointerEvent(type, pointerType!, point, (RawInputModifiers)modifier, pointerId,
             coalescedEvents);
     }
 
-    private bool OnPointerDown(JSObject args)
+    public bool OnPointerDown(string pointerType, long pointerId, int buttons, double offsetX, double offsetY,
+        double pressure, double tiltX, double tiltY, double twist, int modifier)
     {
-        var pointerType = args.GetPropertyAsString("pointerType") ?? "mouse";
         var type = pointerType switch
         {
             "touch" => RawPointerEventType.TouchBegin,
-            _ => args.GetPropertyAsInt32("button") switch
+            _ => buttons switch
             {
                 0 => RawPointerEventType.LeftButtonDown,
                 1 => RawPointerEventType.MiddleButtonDown,
@@ -110,17 +111,17 @@ private bool OnPointerDown(JSObject args)
             }
         };
 
-        var point = ExtractRawPointerFromJsArgs(args);
-        return RawPointerEvent(type, pointerType, point, GetModifiers(args), args.GetPropertyAsInt32("pointerId"));
+        var point = CreateRawPointer(offsetX, offsetY, pressure, tiltX, tiltY, twist);
+        return RawPointerEvent(type, pointerType, point, (RawInputModifiers)modifier, pointerId);
     }
 
-    private bool OnPointerUp(JSObject args)
+    public bool OnPointerUp(string pointerType, long pointerId, int buttons, double offsetX, double offsetY,
+        double pressure, double tiltX, double tiltY, double twist, int modifier)
     {
-        var pointerType = args.GetPropertyAsString("pointerType") ?? "mouse";
         var type = pointerType switch
         {
             "touch" => RawPointerEventType.TouchEnd,
-            _ => args.GetPropertyAsInt32("button") switch
+            _ => buttons switch
             {
                 0 => RawPointerEventType.LeftButtonUp,
                 1 => RawPointerEventType.MiddleButtonUp,
@@ -132,65 +133,28 @@ private bool OnPointerUp(JSObject args)
             }
         };
 
-        var point = ExtractRawPointerFromJsArgs(args);
-        return RawPointerEvent(type, pointerType, point, GetModifiers(args), args.GetPropertyAsInt32("pointerId"));
+        var point = CreateRawPointer(offsetX, offsetY, pressure, tiltX, tiltY, twist);
+        return RawPointerEvent(type, pointerType, point, (RawInputModifiers)modifier, pointerId);
     }
 
-    private bool OnPointerCancel(JSObject args)
+    public bool OnPointerCancel(string pointerType, long pointerId, double offsetX, double offsetY,
+        double pressure, double tiltX, double tiltY, double twist, int modifier)
     {
-        var pointerType = args.GetPropertyAsString("pointerType") ?? "mouse";
         if (pointerType == "touch")
         {
-            var point = ExtractRawPointerFromJsArgs(args);
+            var point = CreateRawPointer(offsetX, offsetY, pressure, tiltX, tiltY, twist);
             RawPointerEvent(RawPointerEventType.TouchCancel, pointerType, point,
-                GetModifiers(args), args.GetPropertyAsInt32("pointerId"));
+                (RawInputModifiers)modifier, pointerId);
         }
 
         return false;
     }
 
-    private bool OnWheel(JSObject args)
-    {
-        return RawMouseWheelEvent(new Point(args.GetPropertyAsDouble("offsetX"), args.GetPropertyAsDouble("offsetY")),
-            new Vector(-(args.GetPropertyAsDouble("deltaX") / 50), -(args.GetPropertyAsDouble("deltaY") / 50)),
-            GetModifiers(args));
-    }
-
-    private static RawInputModifiers GetModifiers(JSObject e)
+    public bool OnWheel(double offsetX, double offsetY, double deltaX, double deltaY, int modifier)
     {
-        var modifiers = RawInputModifiers.None;
-
-        if (e.GetPropertyAsBoolean("ctrlKey"))
-            modifiers |= RawInputModifiers.Control;
-        if (e.GetPropertyAsBoolean("altKey"))
-            modifiers |= RawInputModifiers.Alt;
-        if (e.GetPropertyAsBoolean("shiftKey"))
-            modifiers |= RawInputModifiers.Shift;
-        if (e.GetPropertyAsBoolean("metaKey"))
-            modifiers |= RawInputModifiers.Meta;
-
-        var buttons = e.GetPropertyAsInt32("buttons");
-        if ((buttons & 1L) == 1)
-            modifiers |= RawInputModifiers.LeftMouseButton;
-
-        if ((buttons & 2L) == 2)
-            modifiers |= e.GetPropertyAsString("type") == "pen" ?
-                RawInputModifiers.PenBarrelButton :
-                RawInputModifiers.RightMouseButton;
-
-        if ((buttons & 4L) == 4)
-            modifiers |= RawInputModifiers.MiddleMouseButton;
-
-        if ((buttons & 8L) == 8)
-            modifiers |= RawInputModifiers.XButton1MouseButton;
-
-        if ((buttons & 16L) == 16)
-            modifiers |= RawInputModifiers.XButton2MouseButton;
-
-        if ((buttons & 32L) == 32)
-            modifiers |= RawInputModifiers.PenEraser;
-
-        return modifiers;
+        return RawMouseWheelEvent(new Point(offsetX, offsetY),
+            new Vector(-(deltaX / 50), -(deltaY / 50)),
+            (RawInputModifiers)modifier);
     }
 
     public bool OnDragEvent(JSObject args)
@@ -214,7 +178,7 @@ public bool OnDragEvent(JSObject args)
         _ = AvaloniaModule.ImportStorage();
 
         var position = new Point(args.GetPropertyAsDouble("offsetX"), args.GetPropertyAsDouble("offsetY"));
-        var modifiers = GetModifiers(args);
+        var modifiers = RawInputModifiers.None;// GetModifiers(args);
 
         var effectAllowedStr = dataObject.GetPropertyAsString("effectAllowed") ?? "none";
         var effectAllowed = DragDropEffects.None;
@@ -246,13 +210,15 @@ public bool OnDragEvent(JSObject args)
         var dropEffect = RawDragEvent(eventType, position, modifiers, new BrowserDataObject(dataObject), effectAllowed);
         dataObject.SetProperty("dropEffect", dropEffect.ToString().ToLowerInvariant());
 
+        // Note, due to complications of JS interop, we ignore this return value.
+        // And instead assume, that event is handled for any "drop" and "drag-over" stages.
         return eventType is RawDragEventType.Drop or RawDragEventType.DragOver
                && dropEffect != DragDropEffects.None;
     }
 
-    private bool OnKeyDown(string code, string key, string modifier)
+    public bool OnKeyDown(string code, string key, int modifier)
     {
-        var handled = RawKeyboardEvent(RawKeyEventType.KeyDown, code, key, (RawInputModifiers)int.Parse(modifier));
+        var handled = RawKeyboardEvent(RawKeyEventType.KeyDown, code, key, (RawInputModifiers)modifier);
 
         if (!handled && key.Length == 1)
         {
@@ -262,18 +228,17 @@ private bool OnKeyDown(string code, string key, string modifier)
         return handled;
     }
 
-    private bool OnKeyUp(string code, string key, string modifier)
+    public bool OnKeyUp(string code, string key, int modifier)
     {
-        return RawKeyboardEvent(RawKeyEventType.KeyUp, code, key, (RawInputModifiers)int.Parse(modifier));
+        return RawKeyboardEvent(RawKeyEventType.KeyUp, code, key, (RawInputModifiers)modifier);
     }
 
     private bool RawPointerEvent(
         RawPointerEventType eventType, string pointerType,
         RawPointerPoint p, RawInputModifiers modifiers, long touchPointId,
         Lazy<IReadOnlyList<RawPointerPoint>?>? intermediatePoints = null)
     {
-        if (_inputRoot is { }
-            && _topLevelImpl.Input is { } input)
+        if (_inputRoot is not null && _topLevelImpl.Input is { } input)
         {
             var device = GetPointerDevice(pointerType, touchPointId);
             var args = device is TouchDevice ?

src/Browser/Avalonia.Browser/BrowserInputPane.cs

@@ -7,20 +7,11 @@ namespace Avalonia.Browser;
 
 internal class BrowserInputPane : InputPaneBase
 {
-    public BrowserInputPane(JSObject container)
-    {
-        InputHelper.SubscribeKeyboardGeometryChange(container, OnGeometryChange);
-    }
-
-    private bool OnGeometryChange(JSObject args)
+    public bool OnGeometryChange(double x, double y, double width, double height)
     {
         var oldState = (OccludedRect, State);
 
-        OccludedRect = new Rect(
-            args.GetPropertyAsDouble("x"),
-            args.GetPropertyAsDouble("y"),
-            args.GetPropertyAsDouble("width"),
-            args.GetPropertyAsDouble("height"));
+        OccludedRect = new Rect(x, y, width, height);
         State = OccludedRect.Width != 0 ? InputPaneState.Open : InputPaneState.Closed;
 
         if (oldState != (OccludedRect, State))

src/Browser/Avalonia.Browser/BrowserInsetsManager.cs

@@ -6,11 +6,6 @@ namespace Avalonia.Browser
 {
     internal class BrowserInsetsManager : InsetsManagerBase
     {
-        public BrowserInsetsManager()
-        {
-            DomHelper.InitSafeAreaPadding();
-        }
-
         public override bool? IsSystemBarVisible
         {
             get

src/Browser/Avalonia.Browser/BrowserPlatformSettings.cs

@@ -31,21 +31,25 @@ public override PlatformColorValues GetColorValues()
         };
     }
 
+    public void OnValuesChanged(bool isDarkMode, bool isHighContrast)
+    {
+        _isDarkMode = isDarkMode;
+        _isHighContrast = isHighContrast;
+        OnColorValuesChanged(GetColorValues());
+    }
+
     private void EnsureBackend()
     {
         if (!_isInitialized)
         {
             // WASM module has async nature of initialization. We can't native code right away during components registration. 
             _isInitialized = true;
-
-            var obj = DomHelper.ObserveDarkMode((isDarkMode, isHighContrast) =>
+            var values = DomHelper.GetDarkMode();
+            if (values.Length == 2)
             {
-                _isDarkMode = isDarkMode;
-                _isHighContrast = isHighContrast;
-                OnColorValuesChanged(GetColorValues());
-            });
-            _isDarkMode = obj.GetPropertyAsBoolean("isDarkMode");
-            _isHighContrast = obj.GetPropertyAsBoolean("isHighContrast");
+                _isDarkMode = values[0] > 0;
+                _isHighContrast = values[1] > 0;
+            }
         }
     }
 }