Implement native method for PresentFileExternally in MacOS

osu.Framework/Platform/MacOS/MacOSGameHost.cs

@@ -11,6 +11,8 @@
 using osu.Framework.Input.Bindings;
 using osu.Framework.Input.Handlers;
 using osu.Framework.Input.Handlers.Mouse;
+using osu.Framework.Logging;
+using osu.Framework.Platform.MacOS.Native;
 
 namespace osu.Framework.Platform.MacOS
 {
@@ -51,6 +53,29 @@ protected override void Swap()
                 Renderer.WaitUntilIdle();
         }
 
+        public override bool PresentFileExternally(string filename)
+        {
+            string folderPath = Path.GetDirectoryName(filename);
+
+            if (folderPath == null)
+            {
+                Logger.Log($"Failed to get directory for {filename}", level: LogLevel.Debug);
+                return false;
+            }
+
+            if (!File.Exists(filename) && !Directory.Exists(filename))
+            {
+                Logger.Log($"Cannot find file for '{filename}'", level: LogLevel.Debug);
+
+                // Open the folder without the file selected if we can't find the file
+                OpenFileExternally(folderPath);
+                return true;
+            }
+
+            Finder.OpenFolderAndSelectItem(filename);
+            return true;
+        }
+
         protected override IEnumerable<InputHandler> CreateAvailableInputHandlers()
         {
             var handlers = base.CreateAvailableInputHandlers();

osu.Framework/Platform/MacOS/Native/Finder.cs

@@ -0,0 +1,20 @@
+// Copyright (c) ppy Pty Ltd <[email protected]>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Threading.Tasks;
+
+namespace osu.Framework.Platform.MacOS.Native
+{
+    internal static class Finder
+    {
+        private static readonly NSWorkspace shared_workspace = NSWorkspace.SharedWorkspace();
+
+        internal static void OpenFolderAndSelectItem(string filename)
+        {
+            Task.Run(() =>
+            {
+                shared_workspace.SelectFile(filename);
+            });
+        }
+    }
+}

osu.Framework/Platform/MacOS/Native/NSWorkspace.cs

@@ -0,0 +1,25 @@
+// Copyright (c) ppy Pty Ltd <[email protected]>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+
+namespace osu.Framework.Platform.MacOS.Native
+{
+    internal readonly struct NSWorkspace
+    {
+        internal IntPtr Handle { get; }
+
+        private static readonly IntPtr class_pointer = Class.Get("NSWorkspace");
+        private static readonly IntPtr sel_shared_workspace = Selector.Get("sharedWorkspace");
+        private static readonly IntPtr sel_select_file = Selector.Get("selectFile:inFileViewerRootedAtPath:");
+
+        internal NSWorkspace(IntPtr handle)
+        {
+            Handle = handle;
+        }
+
+        internal static NSWorkspace SharedWorkspace() => new NSWorkspace(Cocoa.SendIntPtr(class_pointer, sel_shared_workspace));
+
+        internal bool SelectFile(string file) => Cocoa.SendBool(Handle, sel_select_file, Cocoa.ToNSString(file));
+    }
+}