Add AnyView implementation

Sources/OpenSwiftUI/Core/BodyAccessor/ViewBodyAccessor.swift

@@ -0,0 +1,17 @@
+//
+//  ViewBodyAccessor.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: WIP
+
+struct ViewBodyAccessor<Container: View>: BodyAccessor {
+    typealias Body = Container.Body
+
+    func updateBody(of: Container, changed: Bool) {
+        guard changed else {
+            return
+        }
+        // TODO
+    }
+}

Sources/OpenSwiftUI/Core/Graph/GraphHost.swift

@@ -181,7 +181,10 @@ class GraphHost {
     }
 
     final func intern<Value>(_ value: Value, id: _GraphInputs.ConstantID) -> Attribute<Value> {
-        fatalError("TODO")
+        let id = id.internID
+        return data.globalSubgraph.apply {
+            data.inputs.intern(value, id: id.internID)
+        }
     }
 
     final func setNeedsUpdate(mayDeferUpdate: Bool) {
@@ -385,7 +388,7 @@ private final class AsyncTransaction {
 
 extension OGGraph {
     final func graphHost() -> GraphHost {
-        context!.assumingMemoryBound(to: GraphHost.self).pointee
+        unsafeBitCast(context, to: GraphHost.self)
     }
 
     fileprivate final func setGraphHost(_ graphHost: GraphHost) {

Sources/OpenSwiftUI/Core/Graph/GraphInputs.swift

@@ -6,8 +6,8 @@ public struct _GraphInputs {
     var cachedEnvironment: MutableBox<CachedEnvironment>
     var phase: Attribute<_GraphInputs.Phase>
     var transaction: Attribute<Transaction>
-    var changedDebugProperties: _ViewDebug.Properties
-    var options: _GraphInputs.Options
+    private var changedDebugProperties: _ViewDebug.Properties
+    private var options: _GraphInputs.Options
     #if canImport(Darwin) // FIXME: See #39
     var mergedInputs: Set<OGAttribute>
     #endif
@@ -54,6 +54,38 @@ public struct _GraphInputs {
         get { customInputs[type] }
         set { customInputs[type] = newValue }
     }
+
+    // MARK: - cachedEnvironment
+
+    @inline(__always)
+    func detechedEnvironmentInputs() -> Self {
+        var newInputs = self
+        newInputs.cachedEnvironment = MutableBox(cachedEnvironment.wrappedValue)
+        return newInputs
+    }
+
+    @inline(__always)
+    mutating func updateCachedEnvironment(_ box: MutableBox<CachedEnvironment>) {
+        cachedEnvironment = box
+        changedDebugProperties.insert(.environment)
+    }
+
+    // MARK: - changedDebugProperties
+
+    @inline(__always)
+    func withEmptyChangedDebugPropertiesInputs<R>(_ body: (_GraphInputs) -> R) -> R {
+        var inputs = self
+        inputs.changedDebugProperties = []
+        return body(inputs)
+    }
+
+    // MARK: - options
+
+    @inline(__always)
+    var enableLayout: Bool {
+        get { options.contains(.enableLayout) }
+        // TODO: setter
+    }
 }
 
 extension _GraphInputs {
@@ -65,9 +97,20 @@ extension _GraphInputs {
 extension _GraphInputs {
     struct Options: OptionSet {
         let rawValue: UInt32
+
+        static var enableLayout: Options { Options(rawValue: 1 << 1) }
     }
 }
 
 extension _GraphInputs {
     typealias ConstantID = Int
+
+    func intern<Value>(_ value: Value, id: ConstantID) -> Attribute<Value> {
+        cachedEnvironment.wrappedValue.intern(value, id: id.internID)
+    }
+}
+
+extension _GraphInputs.ConstantID {
+    @inline(__always)
+    var internID: Self { self & 0x1 }
 }

Sources/OpenSwiftUI/Core/View/CustomView.swift

@@ -0,0 +1,44 @@
+//
+//  CustomView.swift
+//  OpenSwiftUI
+//
+//  Audited for RELEASE_2021
+//  Status: WIP
+//  ID: 9F92ACD17B554E8AB7D29ABB1E796415
+
+internal import OpenGraphShims
+
+extension View {
+    static func makeView(view: _GraphValue<Self>, inputs: _ViewInputs) -> _ViewOutputs {
+        let fields = DynamicPropertyCache.fields(of: Self.self)
+        var inputs = inputs
+        let (body, buffer) = inputs.withMutateGraphInputs { inputs in
+            makeBody(view: view, inputs: &inputs, fields: fields)
+        }
+        let outputs = _ViewDebug.makeView(
+            view: body,
+            inputs: inputs
+        ) { view, inputs in
+            Body._makeView(view: body, inputs: inputs)
+        }
+        if let buffer {
+            buffer.traceMountedProperties(to: body, fields: fields)
+        }
+        return outputs
+    }
+
+    private static func makeBody(
+        view: _GraphValue<Self>,
+        inputs: inout _GraphInputs,
+        fields: DynamicPropertyCache.Fields
+    ) -> (_GraphValue<Body>, _DynamicPropertyBuffer?) {
+        let kind = OGTypeID(Self.self).kind
+        switch kind {
+        case .struct, .enum, .optional, .tuple:
+            let accessor = ViewBodyAccessor<Self>()
+            return accessor.makeBody(container: view, inputs: &inputs, fields: fields)
+        default:
+            fatalError("views must be value types (either a struct or an enum); \(Self.self) is a class.")
+        }
+    }
+}

Sources/OpenSwiftUI/Core/View/TODO/View.swift → Sources/OpenSwiftUI/Core/View/View.swift

@@ -19,7 +19,7 @@
 ///     }
 ///
 /// Assemble the view's body by combining one or more of the built-in views
-/// provided by SwiftUI, like the ``Text`` instance in the example above, plus
+/// provided by OpenSwiftUI, like the ``Text`` instance in the example above, plus
 /// other custom views that you define, into a hierarchy of views. For more
 /// information about creating custom views, see <doc:Declaring-a-Custom-View>.
 ///
@@ -43,16 +43,18 @@
 /// custom view modifiers for easy reuse.
 @_typeEraser(AnyView)
 public protocol View {
-    static func _makeView(view: _GraphValue<Self>, inputs: _ViewInputs) -> _ViewOutputs
-    static func _makeViewList(view: _GraphValue<Self>, inputs: _ViewListInputs) -> _ViewListOutputs
-    static func _viewListCount(inputs: _ViewListCountInputs) -> Int?
-
     /// The type of view representing the body of this view.
     ///
     /// When you create a custom view, Swift infers this type from your
     /// implementation of the required ``View/body-swift.property`` property.
     associatedtype Body: View
 
+    static func _makeView(view: _GraphValue<Self>, inputs: _ViewInputs) -> _ViewOutputs
+
+    static func _makeViewList(view: _GraphValue<Self>, inputs: _ViewListInputs) -> _ViewListOutputs
+
+    static func _viewListCount(inputs: _ViewListCountInputs) -> Int?
+
     /// The content and behavior of the view.
     ///
     /// When you implement a custom view, you must implement a computed
@@ -73,24 +75,25 @@ public protocol View {
     var body: Self.Body { get }
 }
 
-// FIXME
 extension View {
     public static func _makeView(view: _GraphValue<Self>, inputs: _ViewInputs) -> _ViewOutputs {
-        .init()
+        makeView(view: view, inputs: inputs)
     }
+
     public static func _makeViewList(view: _GraphValue<Self>, inputs: _ViewListInputs) -> _ViewListOutputs {
-        .init()
+        fatalError("TODO")
     }
+
     public static func _viewListCount(inputs: _ViewListCountInputs) -> Int? {
-        nil
+        Body._viewListCount(inputs: inputs)
     }
 }
 
+
+// MARK: - Never + View
+
 extension Never: View {
-    public var body: Never {
-        // FIXME: should be "brk #1"
-        fatalError()
-    }
+    public var body: Never { self }
 }
 
 extension View {

Sources/OpenSwiftUI/Core/View/ViewGraph.swift

@@ -28,6 +28,8 @@ final class ViewGraph: GraphHost {
     @Attribute var dimensions: ViewSize
     @Attribute var updateSeed: UInt32
     // TODO
+    @Attribute var defaultLayoutComputer: LayoutComputer
+    // TODO
     var cachedSizeThatFits: CGSize = .invalidValue
     var sizeThatFitsObserver: SizeThatFitsObserver? {
         didSet {
@@ -72,6 +74,8 @@ final class ViewGraph: GraphHost {
         _position = _rootGeometry.origin()
         _dimensions = _rootGeometry.size()
         _updateSeed = Attribute(value: .zero)
+        // TODO
+        _defaultLayoutComputer = Attribute(value: .defaultValue)
         // FIXME
         makeRootView = { view, inputs in
             let rootView = _GraphValue<Body>(view.unsafeCast(to: Body.self))
@@ -200,7 +204,7 @@ final class ViewGraph: GraphHost {
             )
             if requestedOutputs.contains(.layout) {
                 // FIXME
-                inputs.base.options.formUnion(.init(rawValue: 0xe2))
+                // inputs.base.options.formUnion(.init(rawValue: 0xe2))
             }
             requestedOutputs.addRequestedPreferences(to: &inputs)
             _preferenceBridge?.wrapInputs(&inputs)
@@ -211,8 +215,9 @@ final class ViewGraph: GraphHost {
                 as: RootGeometry.self,
                 invalidating: true
             ) { rootGeometry in
-                // FIXME
-                rootGeometry.$layoutDirection = inputs.base.cachedEnvironment.wrappedValue.attribute(keyPath: \.layoutDirection)
+                inputs.withMutableCachedEnviroment {
+                    rootGeometry.$layoutDirection = $0.attribute(keyPath: \.layoutDirection)
+                }
             }
             // TOOD
             return makeRootView(rootView, inputs)