タイムラインの要素のコピー操作を修正

src/Beutl.Utilities/PooledArrayBufferWriter.cs

@@ -105,6 +105,8 @@ public Span<T> GetSpan(int sizeHint = 0)
         return _buffer.AsSpan(_index);
     }
 
+    public static T[] GetArray(PooledArrayBufferWriter<T> self) => self._buffer;
+
     private void CheckAndResizeBuffer(int sizeHint)
     {
         if (sizeHint < 0)

src/Beutl/App.axaml.cs

@@ -1,7 +1,9 @@
 using System.Reflection;
 
 using Avalonia;
+using Avalonia.Controls;
 using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Input.Platform;
 using Avalonia.Markup.Xaml;
 using Avalonia.Media;
 using Avalonia.ReactiveUI;
@@ -104,6 +106,19 @@ public override void OnFrameworkInitializationCompleted()
         base.OnFrameworkInitializationCompleted();
     }
 
+    public static IClipboard? GetClipboard()
+    {
+        switch (Current?.ApplicationLifetime)
+        {
+            case IClassicDesktopStyleApplicationLifetime desktop:
+                return desktop.MainWindow?.Clipboard;
+            case ISingleViewApplicationLifetime { MainView: { } mainview }:
+                return TopLevel.GetTopLevel(mainview)?.Clipboard;
+            default:
+                return null;
+        }
+    }
+
     private MainViewModel GetMainViewModel()
     {
         return _mainViewModel ??= new MainViewModel();

src/Beutl/Services/CoreObjectReborn.cs

@@ -0,0 +1,97 @@
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+using Beutl.Utilities;
+
+namespace Beutl.Services;
+
+public static class CoreObjectReborn
+{
+    private const int DefaultGuidStringSize = 36;
+    private const int BufferSizeDefault = 16 * 1024;
+
+    private static void RebornCore<T>(T obj, PooledArrayBufferWriter<byte> output)
+        where T : class, ICoreObject, new()
+    {
+        var searcher = new ObjectSearcher(obj, v => v is ICoreObject);
+
+        Guid[] ids = searcher.SearchAll()
+            .Cast<ICoreObject>()
+            .Select(v => v.Id)
+            .Distinct()
+            .ToArray();
+
+        // JsonObjectに変換
+        var jsonObject = new JsonObject();
+        obj.WriteToJson(jsonObject);
+
+        // UTF-8に書き込む
+        JsonSerializerOptions options = JsonHelper.SerializerOptions;
+        var writerOptions = new JsonWriterOptions
+        {
+            Encoder = options.Encoder,
+            Indented = options.WriteIndented,
+            MaxDepth = options.MaxDepth
+        };
+
+        using (var writer = new Utf8JsonWriter(output, writerOptions))
+        {
+            jsonObject.WriteTo(writer, options);
+        }
+
+        // Idを置き換える
+        Span<byte> buffer = PooledArrayBufferWriter<byte>.GetArray(output).AsSpan().Slice(0, output.WrittenCount);
+        Span<byte> oldStr = stackalloc byte[DefaultGuidStringSize];
+        Span<byte> newStr = stackalloc byte[DefaultGuidStringSize];
+        foreach (Guid oldId in ids)
+        {
+            Guid newId = Guid.NewGuid();
+            GuidToUtf8(oldId, oldStr);
+            GuidToUtf8(newId, newStr);
+            Span<byte> localBuffer = buffer;
+
+            int index;
+            while ((index = localBuffer.IndexOf(oldStr)) >= 0)
+            {
+                localBuffer = localBuffer.Slice(index);
+                newStr.CopyTo(localBuffer);
+            }
+        }
+    }
+
+    public static void Reborn<T>(T obj, out T newInstance)
+        where T : class, ICoreObject, new()
+    {
+        using var output = new PooledArrayBufferWriter<byte>(BufferSizeDefault);
+        RebornCore(obj, output);
+
+        Span<byte> buffer = PooledArrayBufferWriter<byte>.GetArray(output).AsSpan().Slice(0, output.WrittenCount);
+
+        JsonObject jsonObj = JsonNode.Parse(buffer)!.AsObject();
+        var instance = new T();
+        instance.ReadFromJson(jsonObj);
+
+        newInstance = instance;
+    }
+
+    public static void Reborn<T>(T obj, out string json)
+        where T : class, ICoreObject, new()
+    {
+        using var output = new PooledArrayBufferWriter<byte>(BufferSizeDefault);
+        RebornCore(obj, output);
+
+        Span<byte> buffer = PooledArrayBufferWriter<byte>.GetArray(output).AsSpan().Slice(0, output.WrittenCount);
+        json = Encoding.UTF8.GetString(buffer);
+    }
+
+    private static void GuidToUtf8(Guid id, Span<byte> utf8)
+    {
+        Span<char> utf16 = stackalloc char[DefaultGuidStringSize];
+
+        if (!id.TryFormat(utf16, out _))
+            throw new Exception("Failed to 'Guid.TryFormat'.");
+
+        Encoding.UTF8.GetBytes(utf16, utf8);
+    }
+}

src/Beutl/ViewModels/ElementViewModel.cs

@@ -8,6 +8,7 @@
 using Beutl.Commands;
 using Beutl.Models;
 using Beutl.ProjectSystem;
+using Beutl.Services;
 using Beutl.Utilities;
 
 using Reactive.Bindings;
@@ -20,7 +21,6 @@ namespace Beutl.ViewModels;
 public sealed class ElementViewModel : IDisposable
 {
     private readonly CompositeDisposable _disposables = new();
-    private IClipboard? _clipboard;
 
     public ElementViewModel(Element element, TimelineViewModel timeline)
     {
@@ -163,11 +163,6 @@ public ElementViewModel(Element element, TimelineViewModel timeline)
 
     public List<KeyBinding> KeyBindings { get; }
 
-    public void SetClipboard(IClipboard? clipboard)
-    {
-        _clipboard = clipboard;
-    }
-
     public void Dispose()
     {
         _disposables.Dispose();
@@ -239,7 +234,7 @@ public async Task SubmitViewModelChanges()
 
     private async ValueTask<bool> SetClipboard()
     {
-        IClipboard? clipboard = _clipboard;
+        IClipboard? clipboard = App.GetClipboard();
         if (clipboard != null)
         {
             var jsonNode = new JsonObject();
@@ -323,11 +318,7 @@ private void OnSplit(TimeSpan timeSpan)
         TimeSpan forwardLength = absTime - Model.Start;
         TimeSpan backwardLength = Model.Length - forwardLength;
 
-        var jsonNode = new JsonObject();
-        Model.WriteToJson(jsonNode);
-        string json = jsonNode.ToJsonString(JsonHelper.SerializerOptions);
-        var backwardLayer = new Element();
-        backwardLayer.ReadFromJson(JsonNode.Parse(json)!.AsObject());
+        CoreObjectReborn.Reborn(Model, out Element backwardLayer);
 
         Scene.MoveChild(Model.ZIndex, Model.Start, forwardLength, Model).DoAndRecord(CommandRecorder.Default);
         backwardLayer.Start = absTime;

src/Beutl/Views/ElementView.axaml.cs

@@ -72,8 +72,6 @@ private void OnDataContextDetached(ElementViewModel obj)
         obj.AnimationRequested = (_, _) => Task.CompletedTask;
         _disposable1?.Dispose();
         _disposable1 = null;
-
-        obj.SetClipboard(null);
     }
 
     private void OnDataContextAttached(ElementViewModel obj)
@@ -143,8 +141,6 @@ await Dispatcher.UIThread.InvokeAsync(async () =>
 
         _disposable1 = obj.Model.GetObservable(Element.IsEnabledProperty)
             .Subscribe(b => Dispatcher.UIThread.InvokeAsync(() => border.Opacity = b ? 1 : 0.5));
-
-        obj.SetClipboard(TopLevel.GetTopLevel(this)?.Clipboard);
     }
 
     protected override void OnAttachedToLogicalTree(LogicalTreeAttachmentEventArgs e)

src/Beutl/Views/Timeline.axaml.cs

@@ -108,14 +108,16 @@ private void OnDataContextAttached(TimelineViewModel vm)
                         string? json = await clipboard.GetTextAsync();
                         if (json != null)
                         {
-                            var layer = new Element();
-                            layer.ReadFromJson(JsonNode.Parse(json)!.AsObject());
-                            layer.Start = ViewModel.ClickedFrame;
-                            layer.ZIndex = ViewModel.CalculateClickedLayer();
+                            var oldElement = new Element();
+                            oldElement.ReadFromJson(JsonNode.Parse(json)!.AsObject());
+                            CoreObjectReborn.Reborn(oldElement, out Element newElement);
 
-                            layer.Save(RandomFileNameGenerator.Generate(Path.GetDirectoryName(ViewModel.Scene.FileName)!, Constants.ElementFileExtension));
+                            newElement.Start = ViewModel.ClickedFrame;
+                            newElement.ZIndex = ViewModel.CalculateClickedLayer();
 
-                            ViewModel.Scene.AddChild(layer).DoAndRecord(CommandRecorder.Default);
+                            newElement.Save(RandomFileNameGenerator.Generate(Path.GetDirectoryName(ViewModel.Scene.FileName)!, Constants.ElementFileExtension));
+
+                            ViewModel.Scene.AddChild(newElement).DoAndRecord(CommandRecorder.Default);
                         }
                     }
                 }