Update SafeAreaInsets API

Sources/OpenSwiftUICore/Layout/SafeAreaInsets.swift

@@ -0,0 +1,249 @@
+//
+//  SafeAreaInsets.swift
+//  OpenSwiftUICore
+//
+//  Audited for iOS 18.0
+//  Status: WIP
+//  ID: C4DC82F2A500E9B6DEA3064A36584B42 (SwiftUICore)
+
+import Foundation
+package import OpenGraphShims
+
+// MARK: - SafeAreaRegions
+
+/// A set of symbolic safe area regions.
+@frozen
+public struct SafeAreaRegions: OptionSet {
+    public let rawValue: UInt
+
+    @inlinable
+    public init(rawValue: UInt) { self.rawValue = rawValue }
+
+    /// The safe area defined by the device and containers within the
+    /// user interface, including elements such as top and bottom bars.
+    public static let container = SafeAreaRegions(rawValue: 1 << 0)
+
+    /// The safe area matching the current extent of any software
+    /// keyboard displayed over the view content.
+    public static let keyboard = SafeAreaRegions(rawValue: 1 << 1)
+
+    /// All safe area regions.
+    public static let all = SafeAreaRegions(rawValue: .max)
+
+    package static let background = SafeAreaRegions(rawValue: 1 << 0)
+}
+
+// MARK: - SafeAreaInsets [WIP]
+
+package struct SafeAreaInsets: Equatable {
+    package enum OptionalValue: Equatable {
+        case empty
+        indirect case insets(SafeAreaInsets)
+    }
+
+    package struct Element: Equatable {
+        package var regions: SafeAreaRegions
+        package var insets: EdgeInsets
+
+        package init(regions: SafeAreaRegions, insets: EdgeInsets) {
+            self.regions = regions
+            self.insets = insets
+        }
+    }
+
+    package var space: CoordinateSpace.ID
+
+    package var elements: [Element]
+
+    package var next: OptionalValue
+
+    package init(space: CoordinateSpace.ID, elements: [Element]) {
+        self.space = space
+        self.elements = elements
+        self.next = .empty
+    }
+
+    package init(space: CoordinateSpace.ID, elements: [Element], next: OptionalValue) {
+        self.space = space
+        self.elements = elements
+        self.next = next
+    }
+
+    package func resolve(regions: SafeAreaRegions, in ctx: _PositionAwarePlacementContext) -> EdgeInsets {
+        // preconditionFailure("TODO")
+        .zero
+    }
+
+    private func adjust(
+        _ rect: inout CGRect,
+        regions: SafeAreaRegions,
+        to: _PositionAwarePlacementContext
+    )  {
+        // preconditionFailure("TODO")
+    }
+}
+
+// MARK: - _SafeAreaInsetsModifier [WIP]
+
+package struct _SafeAreaInsetsModifier: MultiViewModifier, PrimitiveViewModifier, Equatable {
+    var elements: [SafeAreaInsets.Element]
+    var nextInsets: SafeAreaInsets.OptionalValue?
+
+    package init() {
+        elements = []
+        nextInsets = nil
+    }
+
+    package init(elements: [SafeAreaInsets.Element], nextInsets: SafeAreaInsets.OptionalValue? = nil) {
+        self.elements = elements
+        self.nextInsets = nextInsets
+    }
+
+    nonisolated package static func _makeView(
+        modifier: _GraphValue<Self>,
+        inputs: _ViewInputs,
+        body: @escaping (_Graph, _ViewInputs) -> _ViewOutputs
+    ) -> _ViewOutputs {
+        var inputs = inputs
+        let space = CoordinateSpace.ID()
+        if inputs.needsGeometry {
+            // TODO
+        }
+        inputs.transform = Attribute(
+            Transform(
+                space: space,
+                transform: inputs.transform,
+                position: inputs.position,
+                size: inputs.size
+            )
+        )
+        inputs.safeAreaInsets = OptionalAttribute(
+            Attribute(
+                Insets(
+                    space: space,
+                    modifier: modifier.value,
+                    next: inputs.safeAreaInsets
+                )
+            )
+        )
+        return body(_Graph(), inputs)
+    }
+
+    private struct Insets: Rule, AsyncAttribute {
+        let space: CoordinateSpace.ID
+        @Attribute var modifier: _SafeAreaInsetsModifier
+        @OptionalAttribute var next: SafeAreaInsets?
+
+        var value: SafeAreaInsets {
+            let insets: SafeAreaInsets.OptionalValue
+            if let nextInsets = modifier.nextInsets {
+                insets = nextInsets
+            } else {
+                if let next {
+                    insets = .insets(next)
+                } else {
+                    insets = .empty
+                }
+            }
+            return SafeAreaInsets(space: space, elements: modifier.elements, next: insets)
+        }
+    }
+
+    private struct Transform: Rule, AsyncAttribute {
+        let space: CoordinateSpace.ID
+        @Attribute var transform: ViewTransform
+        @Attribute var position: ViewOrigin
+        @Attribute var size: ViewSize
+
+        var value: ViewTransform {
+            var transform = transform
+            transform.appendPosition(position.value)
+            transform.appendSizedSpace(id: space, size: size.value)
+            return transform
+        }
+    }
+}
+
+extension _SafeAreaInsetsModifier {
+    @MainActor
+    @preconcurrency
+    package init(insets: EdgeInsets, nextInsets: SafeAreaInsets.OptionalValue? = nil) {
+        self.elements = [.init(regions: .container, insets: insets)]
+        self.nextInsets = nextInsets
+    }
+}
+
+extension _PositionAwarePlacementContext {
+    package func safeAreaInsets(matching regions: SafeAreaRegions = .all) -> EdgeInsets {
+        guard let unadjustedSafeAreaInsets else {
+            return .zero
+        }
+        return unadjustedSafeAreaInsets.resolve(regions: regions, in: self)
+    }
+}
+
+// MARK: - SafeAreaInsetsModifier
+
+package typealias SafeAreaInsetsModifier = ModifiedContent<_PaddingLayout, _SafeAreaInsetsModifier>
+
+extension View {
+    @MainActor
+    @preconcurrency
+    public func _safeAreaInsets(_ insets: EdgeInsets) -> some View {
+        safeAreaInsets(insets, next: nil)
+    }
+
+    @MainActor
+    @preconcurrency
+    package func safeAreaInsets(_ insets: EdgeInsets, next: SafeAreaInsets.OptionalValue? = nil) -> ModifiedContent<Self, SafeAreaInsetsModifier> {
+        modifier(
+            _PaddingLayout(insets: insets)
+                .concat(_SafeAreaInsetsModifier(insets: insets, nextInsets: next))
+        )
+    }
+}
+
+// MARK: - ResolvedSafeAreaInsets
+
+package struct ResolvedSafeAreaInsets: Rule, AsyncAttribute {
+    let regions: SafeAreaRegions
+    @Attribute var environment: EnvironmentValues
+    @Attribute var size: ViewSize
+    @Attribute var position: ViewOrigin
+    @Attribute var transform: ViewTransform
+    @OptionalAttribute var safeAreaInsets: SafeAreaInsets?
+
+    package init(
+        regions: SafeAreaRegions,
+        environment: Attribute<EnvironmentValues>,
+        size: Attribute<ViewSize>,
+        position: Attribute<ViewOrigin>,
+        transform: Attribute<ViewTransform>,
+        safeAreaInsets: OptionalAttribute<SafeAreaInsets>
+    ) {
+        self.regions = regions
+        self._environment = environment
+        self._size = size
+        self._position = position
+        self._transform = transform
+        self._safeAreaInsets = safeAreaInsets
+    }
+
+    package var value: EdgeInsets {
+        let context = AnyRuleContext(context)
+        guard let safeAreaInsetsAttribute = $safeAreaInsets else {
+            return .zero
+        }
+        return context[safeAreaInsetsAttribute].resolve(
+            regions: regions,
+            in: _PositionAwarePlacementContext(
+                context: context,
+                size: _size,
+                environment: _environment,
+                transform: _transform,
+                position: _position,
+                safeAreaInsets: _safeAreaInsets
+            )
+        )
+    }
+}