Add geometry change invalidation support (#881)

Author: Kyle-Ye

Sources/COpenSwiftUI/Shims/UIKit/UIKit_Private.h

@@ -36,6 +36,9 @@ OPENSWIFTUI_ASSUME_NONNULL_BEGIN
 
 @interface UIView (OpenSwiftUI_SPI)
 - (instancetype)_initWithLayer:(CALayer *)layer;
+- (void)_geometryChanged:(const void *)geometry forAncestor:(nullable UIView *)ancestor;
+- (void)_registerForGeometryChanges;
+- (void)_unregisterForGeometryChanges;
 - (BOOL)_shouldAnimatePropertyWithKey_openswiftui_safe_wrapper:(NSString *)key OPENSWIFTUI_SWIFT_NAME(_shouldAnimateProperty(withKey:));
 - (void)_setFocusInteractionEnabled_openswiftui_safe_wrapper:(BOOL)enabled OPENSWIFTUI_SWIFT_NAME(_setFocusInteractionEnabled(_:));
 @property(nonatomic, readonly, nullable) UIViewController *_viewControllerForAncestor_openswiftui_safe_wrapper OPENSWIFTUI_SWIFT_NAME(_viewControllerForAncestor);

Sources/OpenSwiftUI/Integration/Hosting/UIKit/View/UIHostingView+Extension.swift

@@ -280,7 +280,18 @@ extension _UIHostingView: ViewRendererHost {
     }
 
     package func updateTransform() {
+        base.updateTransform()
+
+        // TODO: Notify UIKit related bridges
         _openSwiftUIUnimplementedWarning()
+
+        if !safeAreaRegions.contains(.container) {
+            invalidateProperties(.safeArea, mayDeferUpdate: false)
+        }
+    }
+
+    package func updateTransformWithoutGeometryObservation() {
+        base.updateTransformWithoutGeometryObservation()
     }
 
     package func updateSize() {
@@ -356,6 +367,11 @@ extension _UIHostingView {
 
 extension _UIHostingView: RootTransformProvider {
     package func rootTransform() -> ViewTransform {
+        if !_base.registeredForGeometryChanges {
+            _base.registeredForGeometryChanges = true
+            _registerForGeometryChanges()
+        }
+        // TODO
         _openSwiftUIUnimplementedWarning()
         return .init()
     }
@@ -392,4 +408,3 @@ public func _makeUIHostingView<Content>(_ view: Content) -> NSObject where Conte
 }
 
 #endif
-

Sources/OpenSwiftUI/Integration/Hosting/UIKit/View/UIHostingView.swift

@@ -243,6 +243,13 @@ open class _UIHostingView<Content>: UIView, XcodeViewDebugDataProvider where Con
         base.layoutSubviews()
     }
 
+    override dynamic open func _geometryChanged(
+        _ geometry: UnsafeRawPointer,
+        forAncestor ancestor: UIView?
+    ) {
+        base._geometryChanged(geometry, forAncestor: ancestor)
+    }
+
     override dynamic open var frame: CGRect {
         get {
             super.frame

Sources/OpenSwiftUI/Integration/Hosting/UIKit/View/UIHostingViewBase.swift

@@ -230,8 +230,30 @@ package class UIHostingViewBase {
         }
     }
 
+    @inline(__always)
+    func updateTransform() {
+        guard let uiView else {
+            return
+        }
+        if !viewGraph.invalidateTransform(), registeredForGeometryChanges {
+            uiView._unregisterForGeometryChanges()
+            registeredForGeometryChanges = false
+        }
+    }
+
     package func updateTransformWithoutGeometryObservation() {
-        _openSwiftUIUnimplementedFailure()
+        guard let uiView else {
+            return
+        }
+        let wasRegisteredForGeometryChanges = registeredForGeometryChanges
+        if !viewGraph.invalidateTransform(), registeredForGeometryChanges {
+            uiView._unregisterForGeometryChanges()
+            registeredForGeometryChanges = false
+        }
+        if !wasRegisteredForGeometryChanges, registeredForGeometryChanges {
+            uiView._unregisterForGeometryChanges()
+            registeredForGeometryChanges = false
+        }
     }
 
     @inline(__always)
@@ -510,7 +532,14 @@ package class UIHostingViewBase {
     }
 
     package func _geometryChanged(_: UnsafeRawPointer, forAncestor: UIView?) {
-        _openSwiftUIUnimplementedFailure()
+        guard let host else {
+            return
+        }
+        if registeredForGeometryChanges {
+            host.invalidateProperties(.transform, mayDeferUpdate: false)
+        } else if !options.contains(.registeredForGeometryChanges) {
+            Log.internalError("Received _geometryChanged with no registration for \(self).")
+        }
     }
 
     package func layoutSubviews() {

Sources/OpenSwiftUICore/View/Graph/ViewGraph.swift

@@ -377,7 +377,13 @@ extension ViewGraph {
 
     @discardableResult
     package func invalidateTransform() -> Bool {
-        _openSwiftUIUnimplementedFailure()
+        let rootTransform = $rootTransform
+        guard !rootTransform.valueState.contains(.dirty) else {
+            return false
+        }
+        rootTransform.invalidateValue()
+        delegate?.graphDidChange()
+        return true
     }
 }