Add automaticPadding API support (#422)

* Add AutomaticPadding support

* Add automatic padding tests

Author: Kyle-Ye

Example/OpenSwiftUIUITests/Layout/Modifier/DefaultPaddingUITests.swift

@@ -0,0 +1,63 @@
+//
+//  DefaultPaddingUITests.swift
+//  OpenSwiftUIUITests
+
+import SnapshotTesting
+import Testing
+
+@MainActor
+@Suite(.snapshots(record: .never, diffTool: diffTool))
+struct DefaultPaddingUITests {
+    // MARK: - Basic Padding
+
+    @Test
+    func defaultAutomaticPadding() {
+        struct ContentView: View {
+            var body: some View {
+                Color.red
+                    ._automaticPadding()
+                    .background(Color.blue)
+            }
+        }
+        openSwiftUIAssertSnapshot(of: ContentView())
+    }
+
+    @Test
+    func customAutomaticPadding() {
+        struct ContentView: View {
+            var body: some View {
+                Color.red
+                    ._automaticPadding(
+                        .init(
+                            top: 20,
+                            leading: 20,
+                            bottom: 20,
+                            trailing: 20
+                        )
+                    )
+                    .background(Color.blue)
+            }
+        }
+        openSwiftUIAssertSnapshot(of: ContentView())
+    }
+
+    @Test
+    func mixAutomaticPadding() {
+        struct ContentView: View {
+            var body: some View {
+                VStack {
+                    Color.red
+                        ._automaticPadding()
+                    Color.green
+                        ._automaticPadding()
+                        ._ignoresAutomaticPadding(false)
+                    Color.blue
+                        ._automaticPadding()
+                        ._ignoresAutomaticPadding(true)
+                }
+                .background(Color.yellow)
+            }
+        }
+        openSwiftUIAssertSnapshot(of: ContentView())
+    }
+}

Sources/OpenSwiftUICore/Layout/FixedSizeLayout.swift

@@ -52,6 +52,10 @@ extension _FixedSizeLayout: UnaryLayout {
             height: vertical ? nil : proposedSize.height)
         )
     }
+
+    package func layoutPriority(child: LayoutProxy) -> Double {
+        child.layoutPriority
+    }
 }
 
 // MARK: - View + fixedSize [6.4.41]

Sources/OpenSwiftUICore/Layout/Modifier/DefaultPadding.swift

@@ -3,12 +3,11 @@
 //  OpenSwiftUICore
 //
 //  Audited for 6.5.4
-//  Status: WIP
+//  Status: Complete
 //  ID: 47C1BD8C61550BB60F4F3D12F752D53D (SwiftUICore)
 
-private struct DefaultPaddingKey: EnvironmentKey {
-    static let defaultValue: EdgeInsets = .init(_all: 16.0)
-}
+import Foundation
+import OpenGraphShims
 
 @available(OpenSwiftUI_v3_0, *)
 extension EnvironmentValues {
@@ -19,17 +18,114 @@ extension EnvironmentValues {
     }
 }
 
+// MARK: - DefaultPaddingKey
+
+private struct DefaultPaddingKey: EnvironmentKey {
+    static let defaultValue: EdgeInsets = .init(_all: 16.0)
+}
+
 @available(OpenSwiftUI_v2_0, *)
 extension View {
     /// For use by children in containers to disable the automatic padding that
     /// those containers apply.
     public func _ignoresAutomaticPadding(_ ignoresPadding: Bool) -> some View {
-        _openSwiftUIUnimplementedFailure()
+        modifier(IgnoresAutomaticPaddingLayout(ignoresPadding: ignoresPadding))
     }
 
     /// Applies explicit padding to a view that allows being disabled by that
     /// view using `_ignoresAutomaticPadding`.
     public func _automaticPadding(_ edgeInsets: EdgeInsets? = nil) -> some View {
-        _openSwiftUIUnimplementedFailure()
+        modifier(AutomaticPaddingViewModifier(padding: edgeInsets))
+    }
+}
+
+// MARK: - AutomaticPaddingViewModifier
+
+private struct AutomaticPaddingViewModifier: MultiViewModifier, PrimitiveViewModifier {
+    var padding: EdgeInsets?
+
+    nonisolated static func _makeView(
+        modifier: _GraphValue<AutomaticPaddingViewModifier>,
+        inputs: _ViewInputs,
+        body: @escaping (_Graph, _ViewInputs) -> _ViewOutputs
+    ) -> _ViewOutputs {
+        guard inputs.requestsLayoutComputer || inputs.needsGeometry else {
+            return body(_Graph(), inputs)
+        }
+        let layout = Attribute(PaddingLayout(
+            modifier: modifier.value,
+            environment: inputs.environment,
+            childLayoutComputer: .init()
+        ))
+        return PaddingLayout.Value.makeDebuggableView(
+            modifier: _GraphValue(layout),
+            inputs: inputs,
+            body: body
+        )
+    }
+
+    struct PaddingLayout: Rule, AsyncAttribute {
+        @Attribute var modifier: AutomaticPaddingViewModifier
+        @Attribute var environment: EnvironmentValues
+        @OptionalAttribute var childLayoutComputer: LayoutComputer?
+
+        typealias Value = ModifiedContent<WrappedLayout, _SafeAreaInsetsModifier>
+
+        var value: Value {
+            let ignoresAutomaticPadding = childLayoutComputer?.ignoresAutomaticPadding() ?? false
+            let padding: EdgeInsets
+            if ignoresAutomaticPadding {
+                padding = .zero
+            } else {
+                padding = modifier.padding ?? environment.defaultPadding
+            }
+            return WrappedLayout(base: .init(insets: padding))
+                .concat(_SafeAreaInsetsModifier(insets: padding))
+        }
+
+        struct WrappedLayout: UnaryLayout {
+            var base: _PaddingLayout
+
+            func placement(
+                of child: LayoutProxy,
+                in context: PlacementContextType
+            ) -> _Placement {
+                base.placement(of: child, in: context)
+            }
+
+            func sizeThatFits(
+                in proposedSize: _ProposedSize,
+                context: SizeAndSpacingContext,
+                child: LayoutProxy
+            ) -> CGSize {
+                base.sizeThatFits(in: proposedSize, context: context, child: child)
+            }
+        }
+    }
+}
+
+// MARK: - IgnoresAutomaticPaddingLayout
+
+private struct IgnoresAutomaticPaddingLayout: UnaryLayout {
+    var ignoresPadding: Bool
+
+    func placement(of child: LayoutProxy, in context: PlacementContext) -> _Placement {
+        _Placement(
+            proposedSize: context.proposedSize,
+            aligning: .center,
+            in: context.size
+        )
+    }
+
+    func sizeThatFits(in proposedSize: _ProposedSize, context: SizeAndSpacingContext, child: LayoutProxy) -> CGSize {
+        child.size(in: proposedSize)
+    }
+
+    func layoutPriority(child: LayoutProxy) -> Double {
+        child.layoutPriority
+    }
+
+    func ignoresAutomaticPadding(child: LayoutProxy) -> Bool {
+        ignoresPadding
     }
 }

Sources/OpenSwiftUICore/Layout/UnaryLayout.swift

@@ -31,8 +31,12 @@ package protocol UnaryLayout: Animatable, MultiViewModifier, PrimitiveViewModifi
 }
 
 extension UnaryLayout {
+    package func spacing(in context: SizeAndSpacingContext, child: LayoutProxy) -> Spacing {
+        child.spacing()
+    }
+    
     package func layoutPriority(child: LayoutProxy) -> Double {
-        child.layoutPriority
+        .zero
     }
 
     package func ignoresAutomaticPadding(child: LayoutProxy) -> Bool {
@@ -46,10 +50,6 @@ extension UnaryLayout {
     ) -> _ViewOutputs {
         makeViewImpl(modifier: modifier, inputs: inputs, body: body)
     }
-
-    package func spacing(in context: SizeAndSpacingContext, child: LayoutProxy) -> Spacing {
-        child.spacing()
-    }
 }
 
 // MARK: - DerivedLayout [6.4.41]