Fix macOS clipboard formats mapping (#13197)

* Implement macOS clipboard formats mapping

* Mark DataFormats unstable instead of obsolete (removes warnings in our code base)

* Support non-text data formats in macOS drag source

* Implement SetStrings for IAvnClipboard to support files properly

* Add comments to a confusing part of code

* Update src/Avalonia.Base/Input/DataFormats.cs

---------

Co-authored-by: Jumar Macato <16554748+jmacato@users.noreply.github.com>
Co-authored-by: Dan Walmsley <dan@walms.co.uk>

native/Avalonia.Native/src/OSX/clipboard.mm

@@ -42,6 +42,22 @@ public:
         }
     }
     
+    virtual HRESULT SetStrings(char* type, IAvnStringArray*ppv) override
+    {
+        START_COM_CALL;
+        
+        @autoreleasepool
+        {
+            NSArray<NSString*>* data = GetNSArrayOfStringsAndRelease(ppv);
+            NSString* typeString = [NSString stringWithUTF8String:(const char*)type];
+            if(_item == nil)
+                [_pb setPropertyList: data forType: typeString];
+            else
+                [_item setPropertyList: data forType:typeString];
+            return S_OK;
+        }
+    }
+    
     virtual HRESULT GetStrings(char* type, IAvnStringArray**ppv) override
     {
         START_COM_CALL;

src/Avalonia.Base/Input/DataFormats.cs

@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
@@ -18,7 +19,10 @@ namespace Avalonia.Input
         /// <summary>
         /// Dataformat for one or more filenames
         /// </summary>
-        [Obsolete("Use DataFormats.Files, this format is supported only on desktop platforms."), EditorBrowsable(EditorBrowsableState.Never)]
+        /// <remarks>
+        /// This data format is supported only on desktop platforms.
+        /// </remarks>
+        [Unstable("Use DataFormats.Files, this format is supported only on desktop platforms. And it will be removed in 12.0."), EditorBrowsable(EditorBrowsableState.Never)]
         public static readonly string FileNames = nameof(FileNames);
     }
 }

src/Avalonia.Native/AvaloniaNativeDragSource.cs

@@ -48,10 +48,9 @@ namespace Avalonia.Native
             using (var clipboard = new ClipboardImpl(clipboardImpl))
             using (var cb = new DndCallback(tcs))
             {
-                if (data.Contains(DataFormats.Text))
-                    // API is synchronous, so it's OK
-                    clipboard.SetTextAsync(data.GetText()).Wait();
-                
+                // Native API is synchronous, so it's OK. For now.
+                clipboard.SetDataObjectAsync(data).GetAwaiter().GetResult();
+
                 view.BeginDraggingSession((AvnDragDropEffects)allowedEffects,
                     triggerEvent.GetPosition(tl).ToAvnPoint(), clipboardImpl, cb,
                     GCHandle.ToIntPtr(GCHandle.Alloc(data)));

src/Avalonia.Native/ClipboardImpl.cs

@@ -4,6 +4,7 @@ using System.Linq;
 using System.Threading.Tasks;
 using Avalonia.Input;
 using Avalonia.Input.Platform;
+using Avalonia.Logging;
 using Avalonia.Native.Interop;
 using Avalonia.Platform.Storage;
 using Avalonia.Platform.Storage.FileIO;
@@ -13,6 +14,7 @@ namespace Avalonia.Native
     class ClipboardImpl : IClipboard, IDisposable
     {
         private IAvnClipboard _native;
+        // TODO hide native types behind IAvnClipboard abstraction, so managed side won't depend on macOS.
         private const string NSPasteboardTypeString = "public.utf8-plain-text";
         private const string NSFilenamesPboardType = "NSFilenamesPboardType";
 
@@ -46,7 +48,7 @@ namespace Avalonia.Native
 
         public IEnumerable<string> GetFormats()
         {
-            var rv = new List<string>();
+            var rv = new HashSet<string>();
             using (var formats = _native.ObtainFormats())
             {
                 var cnt = formats.Count;
@@ -58,11 +60,11 @@ namespace Avalonia.Native
                              rv.Add(DataFormats.Text);
                          if (fmt.String == NSFilenamesPboardType)
                          {
-#pragma warning disable CS0618 // Type or member is obsolete
-                            rv.Add(DataFormats.FileNames);
-#pragma warning restore CS0618 // Type or member is obsolete
-                            rv.Add(DataFormats.Files);
+                             rv.Add(DataFormats.FileNames);
+                             rv.Add(DataFormats.Files);
                          }
+                         else
+                             rv.Add(fmt.String);
                     }
                 }
             }
@@ -91,32 +93,71 @@ namespace Avalonia.Native
         public unsafe Task SetDataObjectAsync(IDataObject data)
         {
             _native.Clear();
-            foreach (var fmt in data.GetDataFormats())
+
+            // If there is multiple values with the same "to" format, prefer these that were not mapped.
+            var formats = data.GetDataFormats().Select(f =>
+                {
+                    string from, to;
+                    bool mapped;
+                    if (f == DataFormats.Text)
+                        (from, to, mapped) = (f, NSPasteboardTypeString, true);
+                    else if (f == DataFormats.Files || f == DataFormats.FileNames)
+                        (from, to, mapped) = (f, NSFilenamesPboardType, true);
+                    else (from, to, mapped) = (f, f, false);
+                    return (from, to, mapped);
+                })
+                .GroupBy(p => p.to)
+                .Select(g => g.OrderBy(f => f.mapped).First());
+                
+            
+            foreach (var (fromFormat, toFormat, _) in formats)
             {
-                var o = data.Get(fmt);
-                if(o is string s)
-                    _native.SetText(fmt, s);
-                else if(o is byte[] bytes)
-                    fixed (byte* pbytes = bytes)
-                        _native.SetBytes(fmt, pbytes, bytes.Length);
+                var o = data.Get(fromFormat);
+                switch (o)
+                {
+                    case string s:
+                        _native.SetText(toFormat, s);
+                        break;
+                    case IEnumerable<IStorageItem> storageItems:
+                        using (var strings = new AvnStringArray(storageItems
+                                   .Select(s => s.TryGetLocalPath())
+                                   .Where(p => p is not null)))
+                        {
+                            _native.SetStrings(toFormat, strings);
+                        }
+                        break;
+                    case IEnumerable<string> managedStrings:
+                        using (var strings = new AvnStringArray(managedStrings))
+                        {
+                            _native.SetStrings(toFormat, strings);
+                        }
+                        break;
+                    case byte[] bytes:
+                    {
+                        fixed (byte* pbytes = bytes)
+                            _native.SetBytes(toFormat, pbytes, bytes.Length);
+                        break;
+                    }
+                    default:
+                        Logger.TryGet(LogEventLevel.Warning, LogArea.macOSPlatform)?.Log(this,
+                            "Unsupported IDataObject value type: {0}", o?.GetType().FullName ?? "(null)");
+                        break;
+                }
             }
             return Task.CompletedTask;
         }
 
         public Task<string[]> GetFormatsAsync()
         {
-            using (var n = _native.ObtainFormats())
-                return Task.FromResult(n.ToStringArray());
+            return Task.FromResult(GetFormats().ToArray());
         }
 
         public async Task<object> GetDataAsync(string format)
         {
-            if (format == DataFormats.Text)
+            if (format == DataFormats.Text || format == NSPasteboardTypeString)
                 return await GetTextAsync();
-#pragma warning disable CS0618 // Type or member is obsolete
-            if (format == DataFormats.FileNames)
+            if (format == DataFormats.FileNames || format == NSFilenamesPboardType)
                 return GetFileNames();
-#pragma warning restore CS0618 // Type or member is obsolete
             if (format == DataFormats.Files)
                 return GetFiles();
             using (var n = _native.GetBytes(format))
@@ -146,17 +187,8 @@ namespace Avalonia.Native
 
         public bool Contains(string dataFormat) => Formats.Contains(dataFormat);
 
-        public object Get(string dataFormat)
-        {
-            if (dataFormat == DataFormats.Text)
-                return _clipboard.GetTextAsync().Result;
-            if (dataFormat == DataFormats.Files)
-                return _clipboard.GetFiles();
-#pragma warning disable CS0618
-            if (dataFormat == DataFormats.FileNames)
-#pragma warning restore CS0618
-                return _clipboard.GetFileNames();
-            return null;
-        }
+        public object Get(string dataFormat) => _clipboard.GetDataAsync(dataFormat).GetAwaiter().GetResult();
+
+        public Task SetFromDataObjectAsync(IDataObject dataObject) => _clipboard.SetDataObjectAsync(dataObject);
     }
 }

src/Avalonia.Native/avn.idl

@@ -908,6 +908,7 @@ interface IAvnClipboard : IUnknown
      HRESULT SetText(char* type, char* utf8Text);
      HRESULT ObtainFormats(IAvnStringArray**ppv);
      HRESULT GetStrings(char* type, IAvnStringArray**ppv);
+     HRESULT SetStrings(char* type, IAvnStringArray*ppv);
      HRESULT SetBytes(char* type, void* utf8Text, int len);
      HRESULT GetBytes(char* type, IAvnString**ppv);