[Swift language feature] Implement Swift.Array support

src/Swift.Bindings/tests/IntegrationTests/FunctionalTests/Structs/StructsTests.cs

@@ -2,10 +2,16 @@
 // Licensed under the MIT License.
 
 using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Runtime.InteropServices.Swift;
+using Swift;
 using Swift.Runtime;
+using Swift.Runtime.InteropServices;
 using Swift.StructsTests;
 using Xunit;
 
+
 namespace BindingsGeneration.FunctionalTests
 {
     public class StructTests : IClassFixture<StructTests.TestFixture>
@@ -316,5 +322,38 @@ public async Task TestAsyncStruct()
             stopwatch.Stop();
             Assert.True(Math.Abs(stopwatch.Elapsed.TotalSeconds - seconds) <= 1);
         }
+
+        [Fact]
+        public void TestSwiftArray()
+        {
+            var array = GetArray(42, 17);
+            Assert.Equal(2, array.Count);
+            Assert.Equal(42, array[0]);
+            Assert.Equal(17, array[1]);
+            int sum = SumArray(array);
+            Assert.Equal(42 + 17, sum);
+        }
+
+        // TODO: Remove helper methods when https://github.com/dotnet/runtimelab/issues/2970
+        private static unsafe SwiftArray<int> GetArray(int a, int b)
+        {
+            ArrayBuffer buffer = PInvoke_GetArray(a, b);
+            return SwiftMarshal.MarshalFromSwift<SwiftArray<int>>((SwiftHandle)new IntPtr(&buffer));
+        }
+
+        [UnmanagedCallConv(CallConvs = new Type[] { typeof(CallConvSwift) })]
+        [DllImport("Structs/libStructsTests.dylib", EntryPoint = "$s12StructsTests8getArray1a1bSays5Int32VGAF_AFtF")]
+        private static extern ArrayBuffer PInvoke_GetArray(int a, int b);
+
+        private static unsafe int SumArray(SwiftArray<int> array)
+        {
+            ArrayBuffer buffer = new ArrayBuffer();
+            SwiftMarshal.MarshalToSwift<SwiftArray<int>>(array, new IntPtr(&buffer));
+            return PInvoke_SumArray(buffer);
+        }
+
+        [UnmanagedCallConv(CallConvs = new Type[] { typeof(CallConvSwift) })]
+        [DllImport("Structs/libStructsTests.dylib", EntryPoint = "$s12StructsTests8sumArray5arrays5Int32VSayAEG_tF")]
+        private static extern int PInvoke_SumArray(ArrayBuffer array);
     }
 }

src/Swift.Bindings/tests/IntegrationTests/FunctionalTests/Structs/StructsTests.swift

@@ -170,7 +170,7 @@ public struct StructBuilder
     }
 }
 
-@frozen 
+@frozen
 public struct StructWithThrowingInit
 {
     public var x: Int
@@ -224,11 +224,11 @@ public func createNonFrozenStruct(a: Int, b: Int) -> NonFrozenStruct
 
 public struct TimerStruct {
     let returnValue: Int32
-    
+
     public init(returnValue: Int32) {
         self.returnValue = returnValue
     }
-    
+
     public func waitFor(seconds: UInt64) async -> Int32 {
         do {
             try await Task.sleep(nanoseconds: seconds * 1_000_000_000)
@@ -248,3 +248,12 @@ public struct TimerStruct {
     }
 }
 
+public func getArray(a: Int32, b: Int32) -> Array<Int32>
+{
+    return [a, b]
+}
+
+public func sumArray(array: Array<Int32>) -> Int32
+{
+    return array.reduce(0, +)
+}

src/Swift.Runtime/src/Swift/SwiftArray.cs

@@ -0,0 +1,304 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Runtime.InteropServices.Swift;
+using Swift.Runtime;
+using Swift.Runtime.InteropServices;
+
+namespace Swift;
+
+/// <summary>
+/// Represents a Swift array payload.
+///
+/// The following diagram illustrates the hierarchy of a Swift array type.
+/// The actual implementation may differ:
+///
+///    struct Array
+///    +-----------------------------------------------------------------------+
+///    |   struct ArrayBuffer                                                 |
+///    |   +--------------------------------------------------------------+   |
+///    |   |   struct BridgeStorage                                       |   |
+///    |   |   +------------------------------------------------------+   |   |
+///    |   |   | var rawValue: IntPtr                                 |   |   |
+///    |   |   +------------------------------------------------------+   |   |
+///    |   +--------------------------------------------------------------+   |
+///    +-----------------------------------------------------------------------+
+/// </summary>
+public struct ArrayBuffer
+{
+    public IntPtr storage;
+}
+
+/// <summary>
+/// Represents a Swift collection protocol.
+/// </summary>
+public interface ISwiftCollection { }
+
+/// <summary>
+/// Represents a Swift array.
+/// </summary>
+/// <typeparam name="Element">The element type contained in the array.</typeparam>
+public class SwiftArray<Element> : IDisposable, ISwiftObject
+{
+    static nuint _payloadSize = SwiftObjectHelper<SwiftArray<Element>>.GetTypeMetadata().Size;
+
+    static nuint _elementSize = ElementTypeMetadata.Size;
+
+    private ArrayBuffer _buffer;
+
+    private static Dictionary<Type, string> _protocolConformanceSymbols;
+
+    static SwiftArray()
+    {
+        _protocolConformanceSymbols = new Dictionary<Type, string>
+        {
+            { typeof(ISwiftCollection), "$sSayxGSlsMc" }
+        };
+    }
+
+    public unsafe void Dispose()
+    {
+        if (_buffer.storage != IntPtr.Zero)
+        {
+            Arc.Release(*(IntPtr*)_buffer.storage);
+            _buffer.storage = IntPtr.Zero;
+            GC.SuppressFinalize(this);
+        }
+    }
+
+    unsafe ~SwiftArray()
+    {
+        Arc.Release(*(IntPtr*)_buffer.storage);
+        _buffer.storage = IntPtr.Zero;
+    }
+
+    public static nuint PayloadSize => _payloadSize;
+
+    public ArrayBuffer Payload => _buffer;
+
+    public static nuint ElementSize => _elementSize;
+
+    static TypeMetadata ISwiftObject.GetTypeMetadata()
+    {
+        return TypeMetadata.Cache.GetOrAdd(typeof(SwiftArray<Element>), _ => SwiftArrayPInvokes.PInvoke_getMetadata(TypeMetadataRequest.Complete, ElementTypeMetadata));
+    }
+
+    static TypeMetadata ElementTypeMetadata
+    {
+        get => TypeMetadata.GetTypeMetadataOrThrow<Element>();
+    }
+
+    static ISwiftObject ISwiftObject.NewFromPayload(SwiftHandle handle)
+    {
+        return new SwiftArray<Element>(handle);
+    }
+
+    IntPtr ISwiftObject.MarshalToSwift(IntPtr swiftDest)
+    {
+        var metadata = SwiftObjectHelper<SwiftArray<Element>>.GetTypeMetadata();
+        unsafe
+        {
+            fixed (void* _payloadPtr = &_buffer)
+            {
+                metadata.ValueWitnessTable->InitializeWithCopy((void*)swiftDest, (void*)_payloadPtr, metadata);
+            }
+        }
+        return swiftDest;
+    }
+
+    /// <summary>
+    /// Gets the protocol conformance descriptor for the given type.
+    /// </summary>
+    /// <typeparam name="TProtocol"></typeparam>
+    /// <returns></returns>
+    static ProtocolConformanceDescriptor ISwiftObject.GetProtocolConformanceDescriptor<TProtocol>()
+        where TProtocol : class
+    {
+        if (!_protocolConformanceSymbols.TryGetValue(typeof(TProtocol), out var symbolName))
+        {
+            throw new SwiftRuntimeException($"Attempted to retrieve protocol conformance descriptor for type SwiftArray and protocol {typeof(TProtocol).Name}, but no conformance was found.");
+        }
+        return ProtocolConformanceDescriptor.LoadFromSymbol("/usr/lib/swift/libswiftCore.dylib", symbolName);
+    }
+
+    /// <summary>
+    /// Constructs a new SwiftArray from the given handle.
+    /// </summary>
+    unsafe SwiftArray(SwiftHandle handle)
+    {
+        // copy memory
+        _buffer = *(ArrayBuffer*)handle;
+
+    }
+
+    /// <summary>
+    /// Constructs a new empty SwiftArray.
+    /// </summary>
+    public SwiftArray()
+    {
+        _buffer = SwiftArrayPInvokes.Init(ElementTypeMetadata);
+    }
+
+    /// <summary>
+    /// Gets the number of elements in the array.
+    /// </summary>
+    public unsafe int Count
+    {
+        get
+        {
+            return (int)SwiftArrayPInvokes.Count(_buffer, ElementTypeMetadata);
+        }
+    }
+
+    /// <summary>
+    /// Appends the given element to the array.
+    /// </summary>
+    public unsafe void Append(Element item)
+    {
+        IntPtr payload = IntPtr.Zero;
+        var metadata = SwiftObjectHelper<SwiftArray<Element>>.GetTypeMetadata();
+        try
+        {
+            payload = (IntPtr)NativeMemory.Alloc(ElementSize);
+            SwiftMarshal.MarshalToSwift(item, payload);
+
+            fixed (void* bufferPtr = &_buffer)
+            {
+                SwiftArrayPInvokes.Append(payload, metadata, new SwiftSelf(bufferPtr));
+            }
+        }
+        finally
+        {
+            NativeMemory.Free((void*)payload);
+        }
+    }
+
+    /// <summary>
+    /// Inserts the given element at the given index.
+    /// </summary>
+    public unsafe void Insert(int index, Element item)
+    {
+        IntPtr payload = IntPtr.Zero;
+        var metadata = SwiftObjectHelper<SwiftArray<Element>>.GetTypeMetadata();
+        try
+        {
+            payload = (IntPtr)NativeMemory.Alloc(ElementSize);
+            SwiftMarshal.MarshalToSwift(item, payload);
+            fixed (void* bufferPtr = &_buffer)
+            {
+                SwiftArrayPInvokes.Insert(new SwiftHandle(payload), (nint)index, metadata, new SwiftSelf(bufferPtr));
+            }
+        }
+        finally
+        {
+            NativeMemory.Free((void*)payload);
+        }
+    }
+
+    /// <summary>
+    /// Removes the element at the given index.
+    /// </summary>
+    public unsafe void Remove(int index)
+    {
+        IntPtr payload = IntPtr.Zero;
+        var metadata = SwiftObjectHelper<SwiftArray<Element>>.GetTypeMetadata();
+        try
+        {
+            payload = (IntPtr)NativeMemory.Alloc(ElementSize);
+            SwiftMarshal.MarshalToSwift(index, payload);
+
+            fixed (void* bufferPtr = &_buffer)
+            {
+                SwiftArrayPInvokes.Remove(new SwiftIndirectResult((void*)payload), (nint)index, metadata, new SwiftSelf(bufferPtr));
+            }
+        }
+        finally
+        {
+            NativeMemory.Free((void*)payload);
+        }
+    }
+
+    /// <summary>
+    /// Removes all elements from the array.
+    /// </summary>
+    public unsafe void RemoveAll()
+    {
+        var metadata = SwiftObjectHelper<SwiftArray<Element>>.GetTypeMetadata();
+
+        fixed (void* bufferPtr = &_buffer)
+        {
+            SwiftArrayPInvokes.RemoveAll(1, metadata, new SwiftSelf(bufferPtr));
+        }
+    }
+
+    /// <summary>
+    /// Gets or sets the element at the given index.
+    /// </summary>
+    public unsafe Element this[int index]
+    {
+        get
+        {
+            if (index < 0 || index >= Count)
+                throw new IndexOutOfRangeException();
+
+            IntPtr payload = (IntPtr)NativeMemory.Alloc(ElementSize);
+            SwiftArrayPInvokes.Get(new SwiftIndirectResult((void*)payload), (nint)index, _buffer, ElementTypeMetadata);
+            return SwiftMarshal.MarshalFromSwift<Element>(new SwiftHandle(payload));
+        }
+        set
+        {
+            if (index < 0 || index >= Count)
+                throw new IndexOutOfRangeException();
+
+            var metadata = SwiftObjectHelper<SwiftArray<Element>>.GetTypeMetadata();
+            IntPtr payload = (IntPtr)NativeMemory.Alloc(ElementSize);
+            SwiftMarshal.MarshalToSwift(value, payload);
+
+            fixed (void* bufferPtr = &_buffer)
+            {
+                SwiftArrayPInvokes.Set(new SwiftHandle(payload), (nint)index, metadata, new SwiftSelf(bufferPtr));
+            }
+        }
+    }
+}
+
+internal static class SwiftArrayPInvokes
+{
+    [DllImport(KnownLibraries.SwiftCore, EntryPoint = "$sSaMa")]
+    public static extern TypeMetadata PInvoke_getMetadata(TypeMetadataRequest request, TypeMetadata typeMetadata);
+
+    [DllImport(KnownLibraries.SwiftCore, EntryPoint = "$sS2ayxGycfC")]
+    public static extern ArrayBuffer Init(TypeMetadata typeMetadata);
+
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvSwift)])]
+    [DllImport(KnownLibraries.SwiftCore, EntryPoint = "$sSayxSicig")]
+    public static unsafe extern void Get(SwiftIndirectResult result, nint index, ArrayBuffer handle, TypeMetadata elementMetadata);
+
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvSwift)])]
+    [DllImport(KnownLibraries.SwiftCore, EntryPoint = "$sSayxSicis")]
+    public static unsafe extern void Set(SwiftHandle value, nint index, TypeMetadata elementMetadata, SwiftSelf self);
+
+    [DllImport(KnownLibraries.SwiftCore, EntryPoint = "$sSa5countSivg")]
+    public static extern nint Count(ArrayBuffer handle, TypeMetadata elementMetadata);
+
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvSwift)])]
+    [DllImport(KnownLibraries.SwiftCore, EntryPoint = "$sSa6appendyyxnF")]
+    public static unsafe extern void Append(IntPtr value, TypeMetadata metadata, SwiftSelf self);
+
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvSwift)])]
+    [DllImport(KnownLibraries.SwiftCore, EntryPoint = "$sSa9removeAll15keepingCapacityySb_tF")]
+    public static unsafe extern void RemoveAll(byte keepCapacity, TypeMetadata metadata, SwiftSelf self);
+
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvSwift)])]
+    [DllImport(KnownLibraries.SwiftCore, EntryPoint = "$sSa6remove2atxSi_tF")]
+    public static unsafe extern void Remove(SwiftIndirectResult result, nint index, TypeMetadata metadata, SwiftSelf self);
+
+    [UnmanagedCallConv(CallConvs = [typeof(CallConvSwift)])]
+    [DllImport(KnownLibraries.SwiftCore, EntryPoint = "$sSa6insert_2atyxn_SitF")]
+    public static unsafe extern void Insert(SwiftHandle value, nint index, TypeMetadata metadata, SwiftSelf self);
+}