Merge pull request dotnet#2860 from dotnet/ARC

[SwiftBindings] Added pinvokes for handling ARC

src/Swift.Runtime/src/Library/Arc.cs

@@ -0,0 +1,167 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Runtime.InteropServices;
+
+namespace Swift.Runtime;
+
+/// <summary>
+/// Arc is a class containing p/invokes for Swift Automatic Reference Counting and memory management.
+/// </summary>
+public static class Arc {
+    const string swiftCore = "/usr/lib/swift/libswiftCore.dylib";
+
+    /// <summary>
+    /// Retain a heap-allocated Swift object
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    [DllImport(swiftCore, CallingConvention = CallingConvention.Cdecl)]
+    static extern void swift_retain(IntPtr p);
+
+    /// <summary>
+    /// Retain a heap-allocated Swift object
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    /// <returns>The pointer passed in.</returns>
+    /// <exception cref="ArgumentNullException">Throws if p is null</exception>
+    public static IntPtr Retain(IntPtr p)
+    {
+        if (p == IntPtr.Zero)
+            throw new ArgumentNullException(nameof(p));
+        swift_retain(p);
+        return p;
+    }
+
+    /// <summary>
+    /// Check to see if a pointer is in the process of being deallocated.
+    /// </summary>
+    /// <param name="p">A non-null pointer to an unmanaged Swift object</param>
+    /// <returns>True if and only if the pointer in the process of being deallocated.</returns>
+    [DllImport(swiftCore, CallingConvention = CallingConvention.Cdecl)]
+    [return: MarshalAs(UnmanagedType.I1)]
+    static extern bool swift_isDeallocating(IntPtr p);
+
+    /// <summary>
+    /// Check to see if a pointer is in the process of being deallocated.
+    /// </summary>
+    /// <param name="p">A non-null pointer to an unmanaged Swift object</param>
+    /// <returns>True if and only if the pointer in the process of being deallocated.</returns>
+    /// <exception cref="ArgumentNullException">Throws if p is null</exception>
+    public static bool IsDeallocating(IntPtr p)
+    {
+        if (p == IntPtr.Zero)
+            throw new ArgumentNullException(nameof(p));
+        return swift_isDeallocating(p);
+    }
+
+    /// <summary>
+    /// Releases a heap-allocated Swift object
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    [DllImport(swiftCore, CallingConvention = CallingConvention.Cdecl)]
+    static extern void swift_release(IntPtr p);
+
+    /// <summary>
+    /// Releases a heap-allocated Swift object
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    /// <returns>The pointer passed in</returns>
+    /// <exception cref="ArgumentNullException">Throws if p is null</exception>
+    /// <exception cref="Exception">Throws if p points to an object that has been deinitialized</exception>
+    public static IntPtr Release(IntPtr p)
+    {
+        if (p == IntPtr.Zero)
+            throw new ArgumentNullException(nameof(p));
+        if (swift_isDeallocating(p))
+        {
+            throw new Exception(string.Format ("Attempt to release a Swift object that has been deinitialized {0}", p.ToString($"X{IntPtr.Size * 2}")));
+        }
+        swift_release(p);
+        return p;
+    }
+
+    /// <summary>
+    /// Retains an 'unowned' heap-allocated Swift object.
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    [DllImport(swiftCore, CallingConvention = CallingConvention.Cdecl)]
+    static extern void swift_unownedRetain(IntPtr p);
+
+    /// <summary>
+    /// Retains an 'unowned' heap-allocated Swift object.
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    /// <returns>The pointer passed in</returns>
+    /// <exception cref="ArgumentNullException">Throws if p is null</exception>
+    public static IntPtr UnownedRetain(IntPtr p)
+    {
+        if (p == IntPtr.Zero)
+            throw new ArgumentNullException(nameof(p));
+        swift_unownedRetain(p);
+        return p;
+    }
+
+    /// <summary>
+    /// Releases an 'unowned' heap-allocated Swift object.
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    [DllImport(swiftCore, CallingConvention = CallingConvention.Cdecl)]
+    static extern void swift_unownedRelease(IntPtr p);
+
+    /// <summary>
+    /// Releases an 'unowned' heap-allocated Swift object.
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    /// <returns>The pointer passed in</returns>
+    /// <exception cref="ArgumentNullException">Throws if p is null</exception>
+    public static IntPtr UnownedRelease(IntPtr p)
+    {
+        if (p == IntPtr.Zero)
+            throw new ArgumentNullException(nameof(p));
+        swift_unownedRelease(p);
+        return p;
+    }
+
+    /// <summary>
+    /// Returns the retain count for the heap-allocated Swift object.
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    /// <returns>The retain count</returns>
+    [DllImport(swiftCore, CallingConvention = CallingConvention.Cdecl)]
+    static extern nint swift_retainCount(IntPtr p);
+
+    /// <summary>
+    /// Returns the retain count for the heap-allocated Swift object
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    /// <returns>The retain count</returns>
+    /// <exception cref="ArgumentNullException">Throws if p is null</exception>
+    public static nint RetainCount(IntPtr p)
+    {
+        if (p == IntPtr.Zero)
+            throw new ArgumentNullException(nameof(p));
+        return swift_retainCount(p);
+    }
+
+    /// <summary>
+    /// Returns the 'unowned' retain count for the heap-allocated Swift object.
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    /// <returns>The unowned retain count</returns>
+    [DllImport(swiftCore, CallingConvention = CallingConvention.Cdecl)]
+    static extern nint swift_unownedRetainCount(IntPtr p);
+
+    /// <summary>
+    /// Returns the 'unowned' retain count for the heap-allocated Swift object.
+    /// </summary>
+    /// <param name="p">Pointer to an unmanaged Swift object, must be non-null.</param>
+    /// <returns>The unowned retain count</returns>
+    /// <exception cref="ArgumentNullException">Throws if p is null</exception>
+    public static nint UnownedRetainCount(IntPtr p)
+    {
+        if (p == IntPtr.Zero)
+            throw new ArgumentNullException(nameof(p));
+        return swift_unownedRetainCount(p);
+    }
+}