Add EmptyViewRendererHost

Author: Kyle-Ye

Sources/OpenSwiftUICore/View/Graph/ViewGraph.swift

@@ -323,26 +323,26 @@ extension ViewGraph {
             self.rawValue = rawValue
         }
 
-        static var _0: Outputs { .init(rawValue: 1 << 0) }
-        static var _1: Outputs { .init(rawValue: 1 << 1) }
-        static var _2: Outputs { .init(rawValue: 1 << 2) }
-        static var _3: Outputs { .init(rawValue: 1 << 3) }
-        static var layout: Outputs { .init(rawValue: 1 << 4) }
+        package static let displayList: ViewGraph.Outputs = .init(rawValue: 1 << 0)
+        package static let platformItemList: ViewGraph.Outputs = .init(rawValue: 1 << 1)
+        package static let viewResponders: ViewGraph.Outputs = .init(rawValue: 1 << 2)
+        package static let layout: ViewGraph.Outputs = .init(rawValue: 1 << 4)
+        package static let focus: ViewGraph.Outputs = .init(rawValue: 1 << 5)
+        package static let all: ViewGraph.Outputs = .init(rawValue: 0xFF)
+        package static let defaults: ViewGraph.Outputs = [.displayList, .viewResponders, .layout, .focus]
 
+        // FIXME
         fileprivate func addRequestedPreferences(to inputs: inout _ViewInputs) {
             inputs.preferences.add(HostPreferencesKey.self)
-            if contains(._0) {
+            if contains(.displayList) {
                 inputs.preferences.add(DisplayList.Key.self)
             }
-            if contains(._2) {
+            if contains(.viewResponders) {
 //                inputs.preferences.add(ViewRespondersKey.self)
             }
-            if contains(._1) {
+            if contains(.platformItemList) {
 //                inputs.preferences.add(PlatformItemList.Key.self)
             }
-            if contains(._3) {
-//                inputs.preferences.add(AccessibilityNodesKe.self)
-            }
         }
     }
 }

Sources/OpenSwiftUICore/View/Graph/ViewRendererHost.swift

@@ -43,13 +43,32 @@ package 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 }
+    var renderingPhase: ViewRenderingPhase { get set }
+    var externalUpdateCount: Int { get set }
     func updateRootView()
-    func requestUpdate(after: Double)
+    func updateEnvironment()
+    func updateFocusedItem()
+    func updateFocusedValues()
+    func updateTransform()
+    func updateSize()
+    func updateSafeArea()
+    func updateScrollableContainerSize()
+    func updateFocusStore()
+    func updateAccessibilityFocus()
+    func updateAccessibilityFocusStore()
+    func updateAccessibilityEnvironment()
+    func requestUpdate(after delay: Double)
+    func renderDisplayList(_ list: DisplayList, asynchronously: Bool, time: Time, nextTime: Time, targetTimestamp: Time?, version: DisplayList.Version, maxVersion: DisplayList.Version) -> Time
+    func didRender()
 }
 
-// MARK: - ViewRendererHost's default implementation for ViewGraphDelegate
+extension ViewRendererHost {
+    package var isRendering: Bool {
+        fatalError("TODO")
+    }
+}
+
+// TODO: FIXME
 
 extension ViewRendererHost {
     package func updateViewGraph<Value>(body: (ViewGraph) -> Value) -> Value {
@@ -134,3 +153,30 @@ extension ViewRendererHost {
         // TODO: Signpost.viewHost
     }
 }
+
+// MARK: - EmptyViewRendererHost
+
+final package class EmptyViewRendererHost: ViewRendererHost {
+    package let viewGraph: ViewGraph
+    package var propertiesNeedingUpdate: ViewRendererHostProperties = []
+    package var renderingPhase: ViewRenderingPhase = .none
+    package var externalUpdateCount: Int = .zero
+    package var currentTimestamp: Time = .zero
+    package init(environment: EnvironmentValues = EnvironmentValues()) {
+        Update.begin()
+        viewGraph = ViewGraph(rootViewType: EmptyView.self, requestedOutputs: [])
+        viewGraph.setEnvironment(environment)
+        initializeViewGraph()
+        Update.end()
+    }
+    package func requestUpdate(after delay: Double) {}
+    package func updateRootView() {}
+    package func updateEnvironment() {}
+    package func updateSize() {}
+    package func updateSafeArea() {}
+    package func updateScrollableContainerSize() {}
+    package func renderDisplayList(_ list: DisplayList, asynchronously: Bool, time: Time, nextTime: Time, targetTimestamp: Time?, version: DisplayList.Version, maxVersion: DisplayList.Version) -> Time {
+        .infinity
+    }
+    package func forEachIdentifiedView(body: (_IdentifiedViewProxy) -> Void) {}
+}