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Merge pull request #2489 from JKamsker/ReadTransform
Add support for on-the-fly document upgrades
2 parents c54674e + 1517f66 commit 8406508

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+189
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lines changed

7 files changed

+189
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lines changed

‎LiteDB.Tests/Database/DocumentUpgrade_Tests.cs‎

Lines changed: 133 additions & 0 deletions
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@@ -0,0 +1,133 @@
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using FluentAssertions;
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using LiteDB.Engine;
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using System.IO;
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using Xunit;
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namespace LiteDB.Tests.Database;
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public class DocumentUpgrade_Tests
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{
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[Fact]
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public void DocumentUpgrade_Test()
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{
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var ms = new MemoryStream();
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using (var db = new LiteDatabase(ms))
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{
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var col = db.GetCollection("col");
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col.Insert(new BsonDocument { ["version"] = 1, ["_id"] = 1, ["name"] = "John" });
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}
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ms.Position = 0;
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using (var db = new LiteDatabase(ms))
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{
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var col = db.GetCollection("col");
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col.Count().Should().Be(1);
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var doc = col.FindById(1);
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doc["version"].AsInt32.Should().Be(1);
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doc["name"].AsString.Should().Be("John");
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doc["age"].AsInt32.Should().Be(0);
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}
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ms.Position = 0;
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using var engine = new LiteEngine(new EngineSettings
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{
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DataStream = ms,
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ReadTransform = (collectionName, val) =>
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{
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if (val is not BsonDocument doc)
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{
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return val;
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}
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if (doc.TryGetValue("version", out var version) && version.AsInt32 == 1)
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{
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doc["version"] = 2;
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doc["age"] = 30;
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}
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return val;
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}
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});
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using (var db = new LiteDatabase(engine))
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{
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var col = db.GetCollection("col");
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col.Count().Should().Be(1);
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var doc = col.FindById(1);
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doc["version"].AsInt32.Should().Be(2);
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doc["name"].AsString.Should().Be("John");
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doc["age"].AsInt32.Should().Be(30);
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}
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}
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[Fact]
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public void DocumentUpgrade_BsonMapper_Test()
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{
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var ms = new MemoryStream();
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using (var db = new LiteDatabase(ms))
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{
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var col = db.GetCollection("col");
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col.Insert(new BsonDocument { ["version"] = 1, ["_id"] = 1, ["name"] = "John" });
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}
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ms.Position = 0;
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using (var db = new LiteDatabase(ms))
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{
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var col = db.GetCollection("col");
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col.Count().Should().Be(1);
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var doc = col.FindById(1);
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doc["version"].AsInt32.Should().Be(1);
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doc["name"].AsString.Should().Be("John");
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doc["age"].AsInt32.Should().Be(0);
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}
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ms.Position = 0;
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var mapper = new BsonMapper();
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mapper.OnDeserialization = (sender, type, val) =>
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{
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if (val is not BsonDocument doc)
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{
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return val;
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}
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if (doc.TryGetValue("version", out var version) && version.AsInt32 == 1)
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{
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doc["version"] = 2;
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doc["age"] = 30;
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}
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return doc;
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};
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using (var db = new LiteDatabase(ms, mapper))
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{
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var col = db.GetCollection("col");
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col.Count().Should().Be(1);
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var doc = col.FindById(1);
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doc["version"].AsInt32.Should().Be(2);
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doc["name"].AsString.Should().Be("John");
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doc["age"].AsInt32.Should().Be(30);
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}
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}
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}

‎LiteDB/Client/Mapper/BsonMapper.Deserialize.cs‎

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@@ -9,6 +9,24 @@ namespace LiteDB
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{
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public partial class BsonMapper
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{
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#region Deserialization Hooks
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/// <summary>
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/// Delegate for deserialization callback.
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/// </summary>
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/// <param name="sender">The BsonMapper instance that triggered the deserialization.</param>
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/// <param name="target">The target type for deserialization.</param>
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/// <param name="value">The BsonValue to be deserialized.</param>
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/// <returns>The deserialized BsonValue.</returns>
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public delegate BsonValue DeserializationCallback(BsonMapper sender, Type target, BsonValue value);
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/// <summary>
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/// Gets called before deserialization of a value
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/// </summary>
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public DeserializationCallback? OnDeserialization { get; set; }
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#endregion Deserialization Hooks
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#region Basic direct .NET convert types
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// direct bson types
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/// </summary>
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public object Deserialize(Type type, BsonValue value)
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{
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if (OnDeserialization is not null)
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{
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var result = OnDeserialization(this, type, value);
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if (result is not null)
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{
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value = result;
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}
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}
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// null value - null returns
82109
if (value.IsNull) return null;
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‎LiteDB/Client/Structures/ConnectionString.cs‎

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@@ -1,4 +1,4 @@
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using LiteDB.Engine;
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using LiteDB.Engine;
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using System;
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using System.Collections.Generic;
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using System.Globalization;
@@ -107,7 +107,7 @@ public ConnectionString(string connectionString)
107107
/// <summary>
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/// Create ILiteEngine instance according string connection parameters. For now, only Local/Shared are supported
109109
/// </summary>
110-
internal ILiteEngine CreateEngine()
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internal ILiteEngine CreateEngine(Action<EngineSettings> engineSettingsAction = null)
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{
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var settings = new EngineSettings
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{
@@ -120,6 +120,8 @@ internal ILiteEngine CreateEngine()
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AutoRebuild = this.AutoRebuild,
121121
};
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engineSettingsAction?.Invoke(settings);
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// create engine implementation as Connection Type
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if (this.Connection == ConnectionType.Direct)
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{

‎LiteDB/Document/DataReader/BsonDataReader.cs‎

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@@ -1,4 +1,4 @@
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using LiteDB.Engine;
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using LiteDB.Engine;
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using System;
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using System.Collections;
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using System.Collections.Generic;
@@ -56,10 +56,10 @@ internal BsonDataReader(IEnumerable<BsonValue> values, string collection, Engine
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if (_source.MoveNext())
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{
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_hasValues = _isFirst = true;
59-
_current = _source.Current;
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_current = _state.ReadTransform(_collection, _source.Current);
6060
}
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}
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catch(Exception ex)
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catch (Exception ex)
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{
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_state.Handle(ex);
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throw;
@@ -102,10 +102,10 @@ public bool Read()
102102
try
103103
{
104104
var read = _source.MoveNext(); // can throw any error here
105-
_current = _source.Current;
105+
_current = _state.ReadTransform(_collection, _source.Current);
106106
return read;
107107
}
108-
catch(Exception ex)
108+
catch (Exception ex)
109109
{
110110
_state.Handle(ex);
111111
throw ex;
@@ -117,7 +117,7 @@ public bool Read()
117117
}
118118
}
119119
}
120-
120+
121121
public BsonValue this[string field]
122122
{
123123
get

‎LiteDB/Engine/EngineSettings.cs‎

Lines changed: 7 additions & 1 deletion
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@@ -1,4 +1,4 @@
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using System;
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using System;
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using System.Collections.Concurrent;
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using System.Collections.Generic;
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using System.ComponentModel;
@@ -7,6 +7,7 @@
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using System.Reflection;
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using System.Text;
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using System.Text.RegularExpressions;
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using static LiteDB.Constants;
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namespace LiteDB.Engine
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/// </summary>
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public bool Upgrade { get; set; } = false;
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/// <summary>
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/// Is used to transform a <see cref="BsonValue"/> from the database on read. This can be used to upgrade data from older versions.
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/// </summary>
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public Func<string, BsonValue, BsonValue> ReadTransform { get; set; }
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/// <summary>
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/// Create new IStreamFactory for datafile
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/// </summary>

‎LiteDB/Engine/EngineState.cs‎

Lines changed: 11 additions & 5 deletions
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@@ -1,4 +1,4 @@
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using System;
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using System;
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using System.Collections.Generic;
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using System.Diagnostics;
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using System.IO;
@@ -9,7 +9,6 @@
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using static LiteDB.Constants;
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1312
namespace LiteDB.Engine
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{
1514
internal class EngineState
@@ -25,7 +24,7 @@ internal class EngineState
2524
#endif
2625

2726
public EngineState(LiteEngine engine, EngineSettings settings)
28-
{
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{
2928
_engine = engine;
3029
_settings = settings;
3130
}
@@ -39,7 +38,7 @@ public bool Handle(Exception ex)
3938
{
4039
LOG(ex.Message, "ERROR");
4140

42-
if (ex is IOException ||
41+
if (ex is IOException ||
4342
(ex is LiteException lex && lex.ErrorCode == LiteException.INVALID_DATAFILE_STATE))
4443
{
4544
_exception = ex;
@@ -51,5 +50,12 @@ public bool Handle(Exception ex)
5150

5251
return true;
5352
}
53+
54+
public BsonValue ReadTransform(string collection, BsonValue value)
55+
{
56+
if (_settings?.ReadTransform is null) return value;
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return _settings.ReadTransform(collection, value);
59+
}
5460
}
55-
}
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}

‎LiteDB/LiteDB.csproj‎

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<SignAssembly Condition="'$(OS)'=='Windows_NT'">true</SignAssembly>
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<AssemblyOriginatorKeyFile Condition="'$(Configuration)' == 'Release'">LiteDB.snk</AssemblyOriginatorKeyFile>
3030
<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
31-
<LangVersion>8.0</LangVersion>
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<LangVersion>latest</LangVersion>
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</PropertyGroup>
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