Addresses issue of upgrading from v4.x databases in LiteDB versions 5.0.18-5.0.20

LiteDB.Tests/Issues/Issue2494_Tests.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+using Xunit;
+
+namespace LiteDB.Tests.Issues;
+
+public class Issue2494_Tests
+{
+    [Fact]
+    public static void Test()
+    {
+        var original = "../../../Resources/Issue_2494_EncryptedV4.db";
+        using var filename = new TempFile(original);
+
+        var connectionString = new ConnectionString(filename)
+        {
+            Password = "pass123",
+            Upgrade = true,
+        };
+
+        using (var db = new LiteDatabase(connectionString)) // <= throws as of version 5.0.18
+        {
+            var col = db.GetCollection<PlayerDto>();
+            col.FindAll();
+        }
+    }
+
+    public class PlayerDto
+    {
+        [BsonId]
+        public Guid Id { get; set; }
+
+        public string Name { get; set; }
+
+        public PlayerDto(Guid id, string name)
+        {
+            Id = id;
+            Name = name;
+        }
+
+        public PlayerDto()
+        {
+        }
+    }
+}

LiteDB/Engine/Disk/StreamFactory/FileStreamFactory.cs

@@ -17,13 +17,15 @@ internal class FileStreamFactory : IStreamFactory
         private readonly string _password;
         private readonly bool _readonly;
         private readonly bool _hidden;
+        private readonly bool _useAesStream;
 
-        public FileStreamFactory(string filename, string password, bool readOnly, bool hidden)
+        public FileStreamFactory(string filename, string password, bool readOnly, bool hidden, bool useAesStream = true)
         {
             _filename = filename;
             _password = password;
             _readonly = readOnly;
             _hidden = hidden;
+            _useAesStream = useAesStream;
         }
 
         /// <summary>
@@ -57,7 +59,7 @@ public Stream GetStream(bool canWrite, bool sequencial)
                 File.SetAttributes(_filename, FileAttributes.Hidden);
             }
 
-            return _password == null ? (Stream)stream : new AesStream(_password, stream);
+            return _password == null || !_useAesStream ? (Stream)stream : new AesStream(_password, stream);
         }
 
         /// <summary>

LiteDB/Engine/EngineSettings.cs

@@ -69,7 +69,7 @@ public class EngineSettings
         /// <summary>
         /// Create new IStreamFactory for datafile
         /// </summary>
-        internal IStreamFactory CreateDataFactory()
+        internal IStreamFactory CreateDataFactory(bool useAesStream = true)
         {
             if (this.DataStream != null)
             {
@@ -85,7 +85,7 @@ internal IStreamFactory CreateDataFactory()
             }
             else if (!string.IsNullOrEmpty(this.Filename))
             {
-                return new FileStreamFactory(this.Filename, this.Password, this.ReadOnly, false);
+                return new FileStreamFactory(this.Filename, this.Password, this.ReadOnly, false, useAesStream);
             }
 
             throw new ArgumentException("EngineSettings must have Filename or DataStream as data source");

LiteDB/Engine/FileReader/FileReaderV7.cs

@@ -42,7 +42,7 @@ public FileReaderV7(EngineSettings settings)
 
         public void Open()
         {
-            var streamFactory = _settings.CreateDataFactory();
+            var streamFactory = _settings.CreateDataFactory(false);
 
             // open datafile from stream factory
             _stream = streamFactory.GetStream(true, true);
@@ -437,7 +437,7 @@ protected virtual void Dispose(bool disposing)
             {
                 if (disposing)
                 {
-                    _stream.Dispose();
+                    _stream?.Dispose();
                     _aes?.Dispose();
                 }
 

LiteDB/Engine/Services/RebuildService.cs

@@ -22,14 +22,19 @@ public RebuildService(EngineSettings settings)
         {
             _settings = settings;
 
+            // test for prior version
+            var bufferV7 = this.ReadFirstBytes(false);
+            if (FileReaderV7.IsVersion(bufferV7))
+            {
+                _fileVersion = 7;
+                return;
+            }
+
             // open, read first 16kb, and close data file
             var buffer = this.ReadFirstBytes();
 
             // test for valid reader to use
-            _fileVersion = 
-                FileReaderV7.IsVersion(buffer) ? 7 :
-                FileReaderV8.IsVersion(buffer) ? 8 : throw LiteException.InvalidDatabase();
-
+            _fileVersion = FileReaderV8.IsVersion(buffer) ? 8 : throw LiteException.InvalidDatabase();
         }
 
         public long Rebuild(RebuildOptions options)
@@ -109,10 +114,10 @@ public long Rebuild(RebuildOptions options)
         /// <summary>
         /// Read first 16kb (2 PAGES) in bytes
         /// </summary>
-        private byte[] ReadFirstBytes()
+        private byte[] ReadFirstBytes(bool useAesStream = true)
         {
             var buffer = new byte[PAGE_SIZE * 2];
-            var factory = _settings.CreateDataFactory();
+            var factory = _settings.CreateDataFactory(useAesStream);
 
             using (var stream = factory.GetStream(false, true))
             {