Add setRootView implementation (#84)

* Add setRootView implementation

* Fix Linux build issue

* Fix WASI Thread issue

Author: Kyle-Ye

Sources/OpenSwiftUI/Core/Update/Update.swift

@@ -7,6 +7,7 @@
 
 internal import COpenSwiftUI
 internal import OpenGraphShims
+import Foundation
 
 extension MovableLock {
     @inline(__always)
@@ -43,6 +44,13 @@ enum Update {
         lock.unlock()
     }
 
+    @inline(__always)
+    static func perform<Value>(_ body: () -> Value) -> Value {
+        begin()
+        defer { end() }
+        return body()
+    }
+    
     static func enqueueAction(_ action: @escaping () -> Void) {
         begin()
         actions.append(action)
@@ -73,11 +81,33 @@ enum Update {
 
     @inline(__always)
     static func syncMain(_ body: () -> Void) {
-        // TODO
-        fatalError("TODO")
+        #if os(WASI)
+        // FIXME: See #76
+        body()
+        #else
+        if Thread.isMainThread {
+            body()
+        } else {
+            withoutActuallyEscaping(body) { escapableBody in
+                MovableLock.syncMain(lock: lock) {
+                    #if canImport(Darwin)
+                    AnyRuleContext(attribute: AnyOptionalAttribute.current.identifier).update(body: escapableBody)
+                    #else
+                    fatalError("See #39")
+                    #endif
+                }
+            }
+        }
+        #endif
     }
 }
 
 extension Update {
     private class TraceHost {}
 }
+
+// FIXME: migrate to use @_extern(c, "xx") in Swift 6
+extension MovableLock {
+    @_silgen_name("_MovableLockSyncMain")
+    static func syncMain(lock: MovableLock ,body: @escaping () -> Void)
+}

Sources/OpenSwiftUI/Core/View/ViewGraph.swift

@@ -180,6 +180,13 @@ final class ViewGraph: GraphHost {
         // TODO
     }
 
+    func setRootView<V: View>(_ view: V) {
+        #if canImport(Darwin)
+        @Attribute(identifier: rootView)
+        var rootView: V
+        rootView = view
+        #endif
+    }
 
     // MARK: - Override Methods
 

Sources/OpenSwiftUI/Core/View/ViewGraphDelegate.swift

@@ -12,3 +12,13 @@ protocol ViewGraphDelegate: GraphDelegate {
     func focusDidChange()
     func rootTransform() -> ViewTransform
 }
+
+extension ViewGraphDelegate {
+    func updateGraph<V>(body: (GraphHost) -> V) -> V {
+        updateViewGraph(body: body)
+    }
+    
+    func rootTransform() -> ViewTransform {
+        ViewTransform()
+    }
+}

Sources/OpenSwiftUI/Core/View/ViewRendererHost.swift

@@ -11,11 +11,31 @@ protocol ViewRendererHost: ViewGraphDelegate {
     var viewGraph: ViewGraph { get }
     var currentTimestamp: Time { get set }
     var propertiesNeedingUpdate: ViewRendererHostProperties { get set }
+    func addImplicitPropertiesNeedingUpdate(to properties: inout ViewRendererHostProperties)
     var isRendering: Bool { get set }
+    func updateRootView()
     func requestUpdate(after: Double)
 }
 
+// MARK: - ViewRendererHost's default implementation for ViewGraphDelegate
+
+extension ViewRendererHost {
+    func updateViewGraph<Value>(body: (ViewGraph) -> Value) -> Value {
+        Update.perform {
+            OGGraph.withoutUpdate {
+                updateGraph()
+                return body(viewGraph)
+            }
+        }
+    }
+}
+
 extension ViewRendererHost {
+    func initializeViewGraph() {
+        viewGraph.delegate = self
+        // TODO: Signpost related
+    }
+    
     func invalidateProperties(_ properties: ViewRendererHostProperties, mayDeferUpdate: Bool) {
         Update.lock.withLock {
             guard !propertiesNeedingUpdate.contains(properties) else {
@@ -36,28 +56,50 @@ extension ViewRendererHost {
     }
 
     func render(interval: Double, updateDisplayList: Bool = true) {
-        Update.begin()
-        defer { Update.end() }
-        guard !isRendering else {
-            return
-        }
-        let update = { [self] in
-            currentTimestamp.advancing(by: interval)
-            let time = currentTimestamp
-            viewGraph.flushTransactions()
-            // Signpost.renderUpdate
-            // TODO
-            viewGraph.updateOutputs(at: time)
+        Update.perform {
+            guard !isRendering else {
+                return
+            }
+            let update = { [self] in
+                currentTimestamp.advancing(by: interval)
+                let time = currentTimestamp
+                viewGraph.flushTransactions()
+                // Signpost.renderUpdate
+                // TODO
+                viewGraph.updateOutputs(at: time)
+            }
+            if Signpost.render.isEnabled {
+                // TODO: Signpost related
+                update()
+            } else {
+                update()
+            }
         }
-        if Signpost.render.isEnabled {
-            // TODO: Signpost related
-            update()
-        } else {
-            update()
+    }
+    
+    static func makeRootView<V: View>(_ view: V) -> some View {
+        view/*.modifier(HitTestBindingModifier())*/
+    }
+    
+    func updateGraph() {
+        var properties = propertiesNeedingUpdate
+        addImplicitPropertiesNeedingUpdate(to: &properties)
+        guard !properties.isEmpty else { return }
+        Update.syncMain {
+            func update(_ property: ViewRendererHostProperties, body: () -> Void) {
+                if properties.contains(property) {
+                    propertiesNeedingUpdate.remove(property)
+                }
+                body()
+            }
+            update(.rootView) { updateRootView() }
+            // TODO:
         }
     }
 }
 
 struct ViewRendererHostProperties: OptionSet {
     let rawValue: UInt16
+    
+    static var rootView: ViewRendererHostProperties { ViewRendererHostProperties(rawValue: 1 << 0) }
 }

Sources/OpenSwiftUI/Integration/UIKit/UIHostingController.swift

@@ -8,7 +8,8 @@ open class UIHostingController<Content> : UIViewController where Content : View
     var host: _UIHostingView<Content>
 
     override open dynamic var keyCommands: [UIKeyCommand]? {
-        fatalError("Unimplemented")
+        // TODO
+        nil
     }
 
     public init(rootView: Content) {

Sources/OpenSwiftUI/Integration/UIKit/UIHostingView.swift

@@ -16,7 +16,7 @@ open class _UIHostingView<Content>: UIView where Content: View {
     private var _rootView: Content
     var viewGraph: ViewGraph
     var currentTimestamp: Time = .zero
-    var propertiesNeedingUpdate: ViewRendererHostProperties = []
+    var propertiesNeedingUpdate: ViewRendererHostProperties = [.rootView] // FIXME
     var isRendering: Bool = false
     var inheritedEnvironment: EnvironmentValues?
     var environmentOverride: EnvironmentValues?
@@ -34,13 +34,30 @@ open class _UIHostingView<Content>: UIView where Content: View {
         // TODO
         // FIXME
         super.init(frame: .zero)
+        
+        initializeViewGraph()
+        // TODO
     }
 
     @available(*, unavailable)
     public required init?(coder _: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
 
+    func setRootView(_ view: Content, transaction: Transaction) {
+        _rootView = view
+        let mutation = CustomGraphMutation { [weak self] in
+            guard let self else { return }
+            updateRootView()
+        }
+        viewGraph.asyncTransaction(
+            transaction,
+            mutation: mutation,
+            style: ._1,
+            mayDeferUpdate: true
+        )
+    }
+    
     var rootView: Content {
         get { _rootView }
         set {
@@ -49,7 +66,10 @@ open class _UIHostingView<Content>: UIView where Content: View {
         }
     }
 
-    
+    func makeRootView() -> some View {
+        _UIHostingView.makeRootView(rootView/*.modifier(EditModeScopeModifier(editMode: .default))*/)
+    }
+        
     @available(macOS, unavailable)
     @available(watchOS, unavailable)
     final public func _viewDebugData() -> [_ViewDebug.Data] {
@@ -114,6 +134,13 @@ open class _UIHostingView<Content>: UIView where Content: View {
 }
 
 extension _UIHostingView: ViewRendererHost {
+    func addImplicitPropertiesNeedingUpdate(to _: inout ViewRendererHostProperties) {}
+
+    func updateRootView() {
+        let rootView = makeRootView()
+        viewGraph.setRootView(rootView)
+    }
+    
     func requestUpdate(after: Double) {
         // TODO
     }
@@ -122,10 +149,6 @@ extension _UIHostingView: ViewRendererHost {
         // TODO
     }
 
-    func updateViewGraph<Value>(body: (ViewGraph) -> Value) -> Value {
-        fatalError("TODO")
-    }
-    
     func outputsDidChange(outputs: ViewGraph.Outputs) {
         // TODO
     }
@@ -138,10 +161,6 @@ extension _UIHostingView: ViewRendererHost {
         fatalError("TODO")
     }
 
-    func updateGraph<V>(body: (GraphHost) -> V) -> V {
-        fatalError("TODO")
-    }
-    
     func graphDidChange() {
         // TODO
     }

TestsHost/OpenSwiftUIUITests/View/View/AnyViewTests.swift

@@ -30,5 +30,20 @@ final class AnyViewTests: XCTestCase {
         window.makeKeyAndVisible()
         vc.view.layoutSubviews()
     }
+    
+    // @Test("BodyAccessor crash for non empty View instance", .bug("#81", relationship: .verifiesFix))
+    func testBasicAnyViewWithProperty() throws {
+        struct ContentView: View {
+            var name = ""
+            var body: some View {
+                AnyView(EmptyView())
+            }
+        }
+        let vc = UIHostingController(rootView: ContentView())
+        let window = UIWindow(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
+        window.rootViewController = vc
+        window.makeKeyAndVisible()
+        vc.view.layoutSubviews()
+    }
 }
 #endif