Revert "Optimize BuildMaterializer()"

This reverts commit c0979b3.

Author: SergeiPavlov

Orm/Xtensive.Orm/Orm/Internals/TypeMapping.cs

@@ -8,12 +8,24 @@
 using Xtensive.Tuples.Transform;
 using Xtensive.Orm.Model;
 
-namespace Xtensive.Orm.Internals;
+namespace Xtensive.Orm.Internals
+{
+  internal readonly struct TypeMapping
+  {
+    public readonly TypeInfo Type;
+    public readonly MapTransform KeyTransform;
+    public readonly IReadOnlyList<ColNum> KeyIndexes;
+    public readonly MapTransform Transform;
 
-internal readonly record struct TypeMapping
-(
-  TypeInfo Type,
-  MapTransform KeyTransform,
-  MapTransform Transform,
-  IReadOnlyList<ColNum> KeyIndexes
-);
+
+    // Constructors
+
+    public TypeMapping(TypeInfo type, MapTransform keyTransform, MapTransform transform, IReadOnlyList<ColNum> keyIndexes)
+    {
+      Type = type;
+      KeyTransform = keyTransform;
+      Transform = transform;
+      KeyIndexes = keyIndexes;
+    }
+  }
+}

Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationContext.cs

@@ -60,11 +60,13 @@ public TypeIdRegistry TypeIdRegistry
 
     public TypeMapping GetTypeMapping(int entityIndex, TypeInfo approximateType, int typeId, IReadOnlyList<Pair<ColNum>> columns)
     {
+      TypeMapping result;
       ref var cache = ref entityMappings[entityIndex];
-      if (cache.SingleItem is TypeMapping result) {
-        return typeId == ResolveTypeToNodeSpecificTypeIdentifier(result.Type)
-          ? result
-          : throw new ArgumentOutOfRangeException("typeId");
+      if (cache.SingleItem != null) {
+        if (typeId != ResolveTypeToNodeSpecificTypeIdentifier(cache.SingleItem?.Type)) {
+          throw new ArgumentOutOfRangeException("typeId");
+        }
+        return cache.SingleItem.Value;
       }
       if (cache.Items.TryGetValue(typeId, out result))
         return result;
@@ -88,8 +90,8 @@ public TypeMapping GetTypeMapping(int entityIndex, TypeInfo approximateType, int
         typeColumnMap = newColumns;
       }
 
-      var allIndexes = MaterializationHelper.CreateSingleSourceMap(descriptor.Count, typeColumnMap);
-      var keyIndexes = allIndexes.Take(keyInfo.TupleDescriptor.Count).ToArray();
+      ArraySegment<ColNum> allIndexes = MaterializationHelper.CreateSingleSourceMap(descriptor.Count, typeColumnMap);
+      ArraySegment<ColNum> keyIndexes = allIndexes.Slice(0, keyInfo.TupleDescriptor.Count);
 
       var transform    = new MapTransform(true, descriptor, allIndexes);
       var keyTransform = new MapTransform(true, keyInfo.TupleDescriptor, keyIndexes);

Orm/Xtensive.Orm/Orm/Linq/Materialization/MaterializationInfo.cs

@@ -6,6 +6,17 @@
 
 using System.Linq.Expressions;
 
-namespace Xtensive.Orm.Linq.Materialization;
+namespace Xtensive.Orm.Linq.Materialization
+{
+  internal sealed class MaterializationInfo
+  {
+    public int EntitiesInRow { get; private set; }
+    public LambdaExpression Expression { get; private set; }
 
-internal readonly record struct MaterializationInfo(int EntitiesInRow, LambdaExpression Expression);
+    public MaterializationInfo(int entitiesInRow, LambdaExpression expression)
+    {
+      EntitiesInRow = entitiesInRow;
+      Expression = expression;
+    }
+  }
+}

Orm/Xtensive.Orm/Orm/Linq/Translator.Materialization.cs

@@ -127,19 +127,14 @@ private Materializer BuildMaterializer(ProjectionExpression projection, IReadOnl
       var materializationInfo = itemProjector.Materialize(context, tupleParameters);
       var elementType = itemProjector.Item.Type;
       var materializeMethod = MaterializationHelper.MaterializeMethodInfo.CachedMakeGenericMethod(elementType);
-
-#if NET8_0_OR_GREATER
-      var itemMaterializerFactoryMethod = elementType.IsNullable()
-          ? MaterializationHelper.CreateNullableItemMaterializerMethodInfo.CachedMakeGenericMethodInvoker(elementType.GetGenericArguments()[0])
-          : MaterializationHelper.CreateItemMaterializerMethodInfo.CachedMakeGenericMethodInvoker(elementType);
-      var itemMaterializer = itemMaterializerFactoryMethod.Invoke(null, materializationInfo.Expression, itemProjector.AggregateType);
-#else
-      var itemMaterializerFactoryMethod = elementType.IsNullable()
-          ? MaterializationHelper.CreateNullableItemMaterializerMethodInfo.CachedMakeGenericMethod(elementType.GetGenericArguments()[0])
+      var itemMaterializerFactoryMethod =
+        elementType.IsNullable()
+          ? MaterializationHelper.CreateNullableItemMaterializerMethodInfo.CachedMakeGenericMethod(
+            elementType.GetGenericArguments()[0])
           : MaterializationHelper.CreateItemMaterializerMethodInfo.CachedMakeGenericMethod(elementType);
-      var itemMaterializer = itemMaterializerFactoryMethod.Invoke(null, [materializationInfo.Expression, itemProjector.AggregateType]);
-#endif
 
+      var itemMaterializer = itemMaterializerFactoryMethod.Invoke(
+        null, new object[] { materializationInfo.Expression, itemProjector.AggregateType });
       Expression<Func<Session, int, MaterializationContext>> materializationContextCtor =
         (s, entityCount) => new MaterializationContext(s, entityCount);
       var materializationContextExpression = materializationContextCtor

Orm/Xtensive.Orm/Orm/Linq/TranslatorContext.cs

@@ -82,23 +82,13 @@ public IReadOnlyList<string> GetMainQueryTags() =>
         ? applyParameters.Keys.OfType<TagProvider>().Select(p => p.Tag).ToList()
         : Array.Empty<string>();
 
-    internal readonly struct TagsRestorer : IDisposable
+    public IDisposable DisableSessionTags()
     {
-      private readonly TranslatorContext context;
-      private readonly IReadOnlyList<string> originalTags;
-
-      public void Dispose() => context.SessionTags = originalTags;
-
-      internal TagsRestorer(TranslatorContext context)
-      {
-        this.context = context;
-        originalTags = context.SessionTags;
-        context.SessionTags = null;
-      }
+      var originalTags = SessionTags;
+      SessionTags = null;
+      return new Disposable((b) => SessionTags = originalTags);
     }
 
-    public TagsRestorer DisableSessionTags() => new(this);
-
     public void RebindApplyParameter(CompilableProvider old, CompilableProvider @new)
     {
       if (applyParameters.TryGetValue(old, out var parameter)) {