Replace ReactiveUI

app/InkForge.Desktop/Models/TextDocumentStore.cs

@@ -0,0 +1,131 @@
+using System.Buffers;
+using System.Text;
+
+using Avalonia.Collections;
+
+using AvaloniaEdit.Document;
+
+using InkForge.Data;
+
+using Microsoft.Data.Sqlite;
+using Microsoft.EntityFrameworkCore;
+
+namespace InkForge.Desktop.Models;
+
+public class TextDocumentStore(IDbContextFactory<NoteDbContext> dbContextFactory)
+{
+	private readonly AvaloniaDictionary<int, TextDocument> _cache = [];
+
+	public void Close(int id)
+	{
+		if (_cache.Remove(id, out var document))
+		{
+			document.Remove(0, document.TextLength);
+		}
+	}
+
+	public TextDocument Get(int id)
+	{
+		if (!_cache.TryGetValue(id, out var document))
+		{
+			using var dbContext = dbContextFactory.CreateDbContext();
+			var connection = dbContext.Database.GetDbConnection();
+			using var command = connection.CreateCommand();
+			command.CommandText = $"SELECT rowid FROM Blobs WHERE Id={id}";
+			using var commandReader = command.ExecuteReader();
+			document = new();
+			if (commandReader.Read())
+			{
+				using SqliteBlob stream = new((SqliteConnection)connection, "Blob", "Value", commandReader.GetInt64(0), true);
+				CopyDocumentContent(stream, document);
+			}
+
+			_cache.Add(id, document);
+		}
+
+		return document;
+
+		static void CopyDocumentContent(Stream stream, TextDocument document)
+		{
+			DocumentTextWriter writer = new(document, 0);
+			StreamReader reader = new(stream, Encoding.UTF8);
+			Span<char> buffer = stackalloc char[128];
+			while (!reader.EndOfStream)
+			{
+				var read = reader.Read(buffer);
+				writer.Write(buffer[..read]);
+			}
+		}
+	}
+
+	public int? Save(int? id, TextDocument textDocument)
+	{
+		var state = textDocument.CreateSnapshot();
+		var bytes = TextBytes(state);
+
+		using var dbContext = dbContextFactory.CreateDbContext();
+		var connection = dbContext.Database.GetDbConnection();
+		using var transaction = dbContext.Database.BeginTransaction();
+		using var command = connection.CreateCommand();
+		command.CommandText = id switch
+		{
+			null => $"INSERT INTO Blobs(Value) VALUES(zeroblob({bytes})) RETURNING (Id, rowid)",
+			_ => $"UPDATE Blobs SET Value=zeroblob({bytes}) WHERE Id={id} RETURNING (Id, rowid)"
+		};
+		using var commandReader = command.ExecuteReader();
+		if (!commandReader.Read())
+		{
+			return null;
+		}
+
+		id = commandReader.GetInt32(0);
+		using (SqliteBlob stream = new((SqliteConnection)connection, "Blobs", "Value", commandReader.GetInt64(1)))
+		{
+			using StreamWriter writer = new(stream, Encoding.UTF8);
+			state.WriteTextTo(writer);
+		}
+
+		transaction.Commit();
+		_cache.TryAdd((int)id, textDocument);
+		return id;
+
+		static int TextBytes(ITextSource text)
+		{
+			int length = 0;
+			Span<byte> byteBuffer = stackalloc byte[128];
+			using var reader = text.CreateReader();
+			ArrayBufferWriter<char> buffer = new();
+			var encoder = Encoding.UTF8.GetEncoder();
+			while (reader.Peek() != -1)
+			{
+				var memory = buffer.GetMemory();
+				buffer.Advance(reader.Read(memory.Span));
+				ReadOnlySpan<char> chars = buffer.WrittenSpan;
+
+			convert:
+				encoder.Convert(buffer.WrittenSpan, byteBuffer, false, out var charsUsed, out var bytesUsed, out _);
+				chars = chars[charsUsed..];
+				if (bytesUsed > 0)
+				{
+					length += bytesUsed;
+					goto convert;
+				}
+
+				Span<char> remaining = [];
+				if (!chars.IsEmpty)
+				{
+					remaining = buffer.GetSpan(chars.Length);
+					chars.CopyTo(remaining);
+				}
+
+				buffer.Clear();
+				if (!remaining.IsEmpty)
+				{
+					buffer.Write(remaining);
+				}
+			}
+
+			return length;
+		}
+	}
+}