Update Metadata+OpenSwiftUI (#196)

* Update OpenGraph folder structure

* Add Metadata+OpenSwiftUI

Author: Kyle-Ye

Package.resolved

@@ -0,0 +1,38 @@
+//
+//  Metadata+OpenSwiftUI.swift
+//  OpenSwiftUICore
+//
+//  Audited for iOS 18.0
+//  Status: Complete
+
+public import OpenGraphShims
+
+extension Metadata {
+    package var isValueType: Bool {
+        switch kind {
+            case .struct, .enum, .optional, .tuple: true
+            default: false
+        }
+    }
+
+    public func genericType(at index: Int) -> any Any.Type {
+        UnsafeRawPointer(rawValue)
+            .advanced(by: index &* 8)
+            .advanced(by: 16)
+            .assumingMemoryBound(to: Any.Type.self)
+            .pointee
+    }
+
+    #if OPENSWIFTUI_SUPPORT_2024_API
+    @inline(__always)
+    package func projectEnum(
+        at ptr: UnsafeRawPointer,
+        tag: Int,
+        _ body: (UnsafeRawPointer) -> Void
+    ) {
+        projectEnumData(UnsafeMutableRawPointer(mutating: ptr))
+        body(ptr)
+        injectEnumTag(tag: UInt32(tag), UnsafeMutableRawPointer(mutating: ptr))
+    }
+    #endif
+}

Sources/OpenSwiftUICore/Attribute/AsyncAttribute.swift renamed to Sources/OpenSwiftUICore/OpenGraph/Attribute/AsyncAttribute.swift

@@ -0,0 +1,77 @@
+//
+//  Metadata+OpenSwiftUITests.swift
+//  OpenSwiftUICoreTests
+
+import OpenGraphShims
+import OpenSwiftUICore
+import Testing
+
+@Suite(.enabled(if: swiftToolchainSupported))
+struct Metadata_OpenSwiftUITests {
+    class T1 {}
+
+    struct T2 {}
+
+    enum T3 {}
+
+    protocol P {}
+
+    @Test
+    func isValueType() {
+        #expect(Metadata(T1.self).isValueType == false)
+        #expect(Metadata(T2.self).isValueType == true)
+        #expect(Metadata(T3.self).isValueType == true)
+        #expect(Metadata(P.self).isValueType == false)
+
+        #expect(Metadata(T1?.self).isValueType == true)
+        #expect(Metadata((T1, T1).self).isValueType == true)
+    }
+
+    @Test
+    func genericType() {
+        struct T1<A, B, C> {}
+        struct T2<A, B> where A: P, B: P {}
+
+        struct P1: P {}
+        struct P2: P {}
+        let t1Type = Metadata(T1<Int, Double, Float>.self)
+        #expect(t1Type.genericType(at: 0) == Int.self)
+        #expect(t1Type.genericType(at: 1) == Double.self)
+        #expect(t1Type.genericType(at: 2) == Float.self)
+
+        let t2Type = Metadata(T2<P1, P2>.self)
+        #expect(t2Type.genericType(at: 0) == P1.self)
+        #expect(t2Type.genericType(at: 1) == P2.self)
+    }
+
+    #if OPENSWIFTUI_SUPPORT_2024_API
+    @Test
+    func projectEnum() {
+        enum T: Equatable {
+            case empty
+            case int64(Int64)
+            case int32(Int32)
+        }
+
+        var t = T.empty
+        let metadata = Metadata(T.self)
+
+        metadata.projectEnum(at: &t, tag: 0) { p in
+            UnsafeMutableRawPointer(mutating: p)
+                .assumingMemoryBound(to: Int64.self)
+                .pointee = 1
+        }
+        #expect(t == .int64(1))
+
+        metadata.projectEnum(at: &t, tag: 1) { p in
+            UnsafeMutableRawPointer(mutating: p)
+                .assumingMemoryBound(to: Int32.self)
+                .pointee = 1
+        }
+        #expect(t == .int32(1))
+
+        metadata.projectEnum(at: &t, tag: 2) { _ in }
+        #expect(t == .empty)
+    }
+    #endif
+}