Move ViewConfiguration ownership to FlutterView

lib/ui/fixtures/ui_test.dart

@@ -539,33 +539,7 @@ void hooksTests() async {
   });
 
   await test('PlatformDispatcher.view getter returns view with provided ID', () {
-    const int viewId = 123456789;
-    _callHook(
-      '_updateWindowMetrics',
-      21,
-      viewId, // window Id
-      1.0, // devicePixelRatio
-      800.0, // width
-      600.0, // height
-      50.0, // paddingTop
-      0.0, // paddingRight
-      40.0, // paddingBottom
-      0.0, // paddingLeft
-      0.0, // insetTop
-      0.0, // insetRight
-      0.0, // insetBottom
-      0.0, // insetLeft
-      0.0, // systemGestureInsetTop
-      0.0, // systemGestureInsetRight
-      0.0, // systemGestureInsetBottom
-      0.0, // systemGestureInsetLeft
-      22.0, // physicalTouchSlop
-      <double>[],  // display features bounds
-      <int>[],     // display features types
-      <int>[],     // display features states
-      0, // Display ID
-    );
-
+    const int viewId = 0;
     expectEquals(PlatformDispatcher.instance.view(id: viewId)?.viewId, viewId);
   });
 

lib/ui/platform_dispatcher.dart

@@ -66,6 +66,14 @@ typedef ErrorCallback = bool Function(Object exception, StackTrace stackTrace);
 // A gesture setting value that indicates it has not been set by the engine.
 const double _kUnsetGestureSetting = -1.0;
 
+// The view ID of PlatformDispatcher.implicitView. This is an
+// implementation detail that may change at any time. Apps
+// should always use PlatformDispatcher.implicitView to determine
+// the current implicit view, if any.
+//
+// Keep this in sync with kImplicitViewId in window/platform_configuration.cc.
+const int _kImplicitViewId = 0;
+
 // A message channel to receive KeyData from the platform.
 //
 // See embedder.cc::kFlutterKeyDataChannel for more information.
@@ -185,9 +193,6 @@ class PlatformDispatcher {
   /// otherwise.
   FlutterView? view({required int id}) => _views[id];
 
-  // A map of opaque platform view identifiers to view configurations.
-  final Map<Object, _ViewConfiguration> _viewConfigurations = <Object, _ViewConfiguration>{};
-
   /// The [FlutterView] provided by the engine if the platform is unable to
   /// create windows, or, for backwards compatibility.
   ///
@@ -213,7 +218,7 @@ class PlatformDispatcher {
   /// * [View.of], for accessing the current view.
   /// * [PlatformDispatcher.views] for a list of all [FlutterView]s provided
   ///   by the platform.
-  FlutterView? get implicitView => _implicitViewEnabled() ? _views[0] : null;
+  FlutterView? get implicitView => _implicitViewEnabled() ? _views[_kImplicitViewId] : null;
 
   @Native<Handle Function()>(symbol: 'PlatformConfigurationNativeApi::ImplicitViewEnabled')
   external static bool _implicitViewEnabled();
@@ -281,13 +286,7 @@ class PlatformDispatcher {
     List<int> displayFeaturesState,
     int displayId,
   ) {
-    final _ViewConfiguration previousConfiguration =
-        _viewConfigurations[id] ?? const _ViewConfiguration();
-    if (!_views.containsKey(id)) {
-      _views[id] = FlutterView._(id, this);
-    }
-    _viewConfigurations[id] = previousConfiguration.copyWith(
-      view: _views[id],
+    final _ViewConfiguration viewConfiguration = _ViewConfiguration(
       devicePixelRatio: devicePixelRatio,
       geometry: Rect.fromLTWH(0.0, 0.0, width, height),
       viewPadding: ViewPadding._(
@@ -314,7 +313,6 @@ class PlatformDispatcher {
         bottom: math.max(0.0, systemGestureInsetBottom),
         left: math.max(0.0, systemGestureInsetLeft),
       ),
-      // -1 is used as a sentinel for an undefined touch slop
       gestureSettings: GestureSettings(
         physicalTouchSlop: physicalTouchSlop == _kUnsetGestureSetting ? null : physicalTouchSlop,
       ),
@@ -326,6 +324,17 @@ class PlatformDispatcher {
       ),
       displayId: displayId,
     );
+
+    final FlutterView? view = _views[id];
+    if (id == _kImplicitViewId && view == null) {
+      // TODO(goderbauer): Remove the implicit creation of the implicit view
+      //   when we have an addView API and the implicit view is added via that.
+      _views[id] = FlutterView._(id, this, viewConfiguration);
+    } else {
+      assert(view != null);
+      view!._viewConfiguration = viewConfiguration;
+    }
+
     _invoke(onMetricsChanged, _onMetricsChangedZone);
   }
 
@@ -1362,10 +1371,8 @@ class _PlatformConfiguration {
 /// An immutable view configuration.
 class _ViewConfiguration {
   const _ViewConfiguration({
-    this.view,
     this.devicePixelRatio = 1.0,
     this.geometry = Rect.zero,
-    this.visible = false,
     this.viewInsets = ViewPadding.zero,
     this.viewPadding = ViewPadding.zero,
     this.systemGestureInsets = ViewPadding.zero,
@@ -1375,37 +1382,6 @@ class _ViewConfiguration {
     this.displayId = 0,
   });
 
-  /// Copy this configuration with some fields replaced.
-  _ViewConfiguration copyWith({
-    FlutterView? view,
-    double? devicePixelRatio,
-    Rect? geometry,
-    bool? visible,
-    ViewPadding? viewInsets,
-    ViewPadding? viewPadding,
-    ViewPadding? systemGestureInsets,
-    ViewPadding? padding,
-    GestureSettings? gestureSettings,
-    List<DisplayFeature>? displayFeatures,
-    int? displayId,
-  }) {
-    return _ViewConfiguration(
-      view: view ?? this.view,
-      devicePixelRatio: devicePixelRatio ?? this.devicePixelRatio,
-      geometry: geometry ?? this.geometry,
-      visible: visible ?? this.visible,
-      viewInsets: viewInsets ?? this.viewInsets,
-      viewPadding: viewPadding ?? this.viewPadding,
-      systemGestureInsets: systemGestureInsets ?? this.systemGestureInsets,
-      padding: padding ?? this.padding,
-      gestureSettings: gestureSettings ?? this.gestureSettings,
-      displayFeatures: displayFeatures ?? this.displayFeatures,
-      displayId: displayId ?? this.displayId,
-    );
-  }
-
-  final FlutterView?  view;
-
   /// The identifier for a display for this view, in
   /// [PlatformDispatcher._displays].
   final int displayId;
@@ -1417,9 +1393,6 @@ class _ViewConfiguration {
   /// window, in logical pixels.
   final Rect geometry;
 
-  /// Whether or not the view is currently visible on the screen.
-  final bool visible;
-
   /// The number of physical pixels on each side of the display rectangle into
   /// which the view can render, but over which the operating system will likely
   /// place system UI, such as the keyboard, that fully obscures any content.
@@ -1488,7 +1461,7 @@ class _ViewConfiguration {
 
   @override
   String toString() {
-    return '$runtimeType[view: $view, geometry: $geometry]';
+    return '$runtimeType[geometry: $geometry]';
   }
 }
 

lib/ui/window.dart

@@ -86,7 +86,7 @@ class Display {
 /// that in the [padding], which is always safe to use for such
 /// calculations.
 class FlutterView {
-  FlutterView._(this.viewId, this.platformDispatcher);
+  FlutterView._(this.viewId, this.platformDispatcher, this._viewConfiguration);
 
   /// The opaque ID for this view.
   final int viewId;
@@ -96,10 +96,8 @@ class FlutterView {
   final PlatformDispatcher platformDispatcher;
 
   /// The configuration of this view.
-  _ViewConfiguration get _viewConfiguration {
-    assert(platformDispatcher._viewConfigurations.containsKey(viewId));
-    return platformDispatcher._viewConfigurations[viewId]!;
-  }
+  // TODO(goderbauer): remove ignore when https://github.com/dart-lang/linter/issues/4562 is fixed.
+  _ViewConfiguration _viewConfiguration; // ignore: prefer_final_fields
 
   /// The [Display] this view is drawn in.
   Display get display {
@@ -373,6 +371,9 @@ class FlutterView {
 
   @Native<Void Function(Pointer<Void>)>(symbol: 'PlatformConfigurationNativeApi::UpdateSemantics')
   external static void _updateSemantics(_NativeSemanticsUpdate update);
+
+  @override
+  String toString() => 'FlutterView(id: $viewId)';
 }
 
 /// Deprecated. Will be removed in a future version of Flutter.
@@ -405,8 +406,15 @@ class SingletonFlutterWindow extends FlutterView {
     'Deprecated to prepare for the upcoming multi-window support. '
     'This feature was deprecated after v3.7.0-32.0.pre.'
   )
-  SingletonFlutterWindow._(super.windowId, super.platformDispatcher)
-      : super._();
+  SingletonFlutterWindow._() : super._(
+    _kImplicitViewId,
+    PlatformDispatcher.instance,
+    const _ViewConfiguration(),
+  );
+
+  // Gets its configuration from the FlutterView with the same ID if it exists.
+  @override
+  _ViewConfiguration get _viewConfiguration => platformDispatcher._views[viewId]?._viewConfiguration ?? super._viewConfiguration;
 
   /// A callback that is invoked whenever the [devicePixelRatio],
   /// [physicalSize], [padding], [viewInsets], [PlatformDispatcher.views], or
@@ -1016,7 +1024,7 @@ enum Brightness {
   'Deprecated to prepare for the upcoming multi-window support. '
   'This feature was deprecated after v3.7.0-32.0.pre.'
 )
-final SingletonFlutterWindow window = SingletonFlutterWindow._(0, PlatformDispatcher.instance);
+final SingletonFlutterWindow window = SingletonFlutterWindow._();
 
 /// Additional data available on each flutter frame.
 class FrameData {

lib/ui/window/platform_configuration.cc

@@ -22,6 +22,7 @@
 namespace flutter {
 namespace {
 
+// Keep this in sync with _kImplicitViewId in ../platform_dispatcher.dart.
 constexpr int kImplicitViewId = 0;
 
 Dart_Handle ToByteData(const fml::Mapping& buffer) {

testing/dart/window_test.dart

@@ -89,4 +89,10 @@ void main() {
     expect(display.refreshRate, 60);
     expect(display.size, implicitView.physicalSize);
   });
+
+  test('FlutterView.toString contains the viewId', () {
+    final FlutterView flutterView = PlatformDispatcher.instance.implicitView!;
+    expect(flutterView.viewId, 0);
+    expect(flutterView.toString(), 'FlutterView(id: 0)');
+  });
 }