Use ref readonly to optimize PackedFieldDescriptor copying

SergeiPavlov · SergeiPavlov · commit a6b935264087 · 2022-03-28T14:40:14.000-07:00
diff --git a/Orm/Xtensive.Orm/Tuples/Packed/PackedTuple.cs b/Orm/Xtensive.Orm/Tuples/Packed/PackedTuple.cs
@@ -11,8 +11,6 @@ namespace Xtensive.Tuples.Packed
   [Serializable]
   internal sealed class PackedTuple : RegularTuple
   {
-    private static readonly object[] EmptyObjectArray = new object[0];
-
     public readonly TupleDescriptor PackedDescriptor;
     public readonly long[] Values;
     public readonly object[] Objects;
@@ -35,24 +33,26 @@ public override Tuple CreateNew()
     public override bool Equals(Tuple other)
     {
       var packedOther = other as PackedTuple;
-      if (packedOther==null)
+      if (packedOther == null)
         return base.Equals(other);
 
       if (ReferenceEquals(packedOther, this))
         return true;
-      if (Descriptor!=packedOther.Descriptor)
+      if (Descriptor != packedOther.Descriptor)
         return false;
 
       var fieldDescriptors = PackedDescriptor.FieldDescriptors;
       var count = Count;
       for (int i = 0; i < count; i++) {
-        ref var descriptor = ref fieldDescriptors[i];
+        ref readonly var descriptor = ref fieldDescriptors[i];
         var thisState = GetFieldState(descriptor);
         var otherState = packedOther.GetFieldState(descriptor);
-        if (thisState!=otherState)
+        if (thisState != otherState) {
           return false;
-        if (thisState!=TupleFieldState.Available)
+        }
+        if (thisState != TupleFieldState.Available) {
           continue;
+        }
         var accessor = descriptor.Accessor;
         if (!accessor.ValueEquals(this, descriptor, packedOther, descriptor))
           return false;
@@ -67,7 +67,7 @@ public override int GetHashCode()
       var fieldDescriptors = PackedDescriptor.FieldDescriptors;
       int result = 0;
       for (int i = 0; i < count; i++) {
-        ref var descriptor = ref fieldDescriptors[i];
+        ref readonly var descriptor = ref fieldDescriptors[i];
         var state = GetFieldState(descriptor);
         var fieldHash = state == TupleFieldState.Available
           ? descriptor.Accessor.GetValueHashCode(this, descriptor)
@@ -77,14 +77,12 @@ public override int GetHashCode()
       return result;
     }
 
-    public override TupleFieldState GetFieldState(int fieldIndex)
-    {
-      return GetFieldState(PackedDescriptor.FieldDescriptors[fieldIndex]);
-    }
+    public override TupleFieldState GetFieldState(int fieldIndex) =>
+      GetFieldState(PackedDescriptor.FieldDescriptors[fieldIndex]);
 
     protected internal override void SetFieldState(int fieldIndex, TupleFieldState fieldState)
     {
-      if (fieldState==TupleFieldState.Null) {
+      if (fieldState == TupleFieldState.Null) {
         throw new ArgumentOutOfRangeException(nameof(fieldState));
       }
 
@@ -93,13 +91,13 @@ protected internal override void SetFieldState(int fieldIndex, TupleFieldState f
 
     public override object GetValue(int fieldIndex, out TupleFieldState fieldState)
     {
-      ref var descriptor = ref PackedDescriptor.FieldDescriptors[fieldIndex];
+      ref readonly var descriptor = ref PackedDescriptor.FieldDescriptors[fieldIndex];
       return descriptor.Accessor.GetUntypedValue(this, descriptor, out fieldState);
     }
 
     public override void SetValue(int fieldIndex, object fieldValue)
     {
-      ref var descriptor = ref PackedDescriptor.FieldDescriptors[fieldIndex];
+      ref readonly var descriptor = ref PackedDescriptor.FieldDescriptors[fieldIndex];
       descriptor.Accessor.SetUntypedValue(this, descriptor, fieldValue);
     }
 
@@ -109,7 +107,7 @@ public void SetFieldState(in PackedFieldDescriptor d, TupleFieldState fieldState
       ref var block = ref Values[d.StateIndex];
       block = (block & ~(3L << d.StateBitOffset)) | (bits << d.StateBitOffset);
 
-      if (fieldState!=TupleFieldState.Available && d.IsObjectField) {
+      if (fieldState != TupleFieldState.Available && d.IsObjectField) {
         Objects[d.ObjectIndex] = null;
       }
     }
@@ -127,7 +125,7 @@ public PackedTuple(TupleDescriptor descriptor)
       Values = new long[PackedDescriptor.ValuesLength];
       Objects = PackedDescriptor.ObjectsLength > 0
         ? new object[PackedDescriptor.ObjectsLength]
-        : EmptyObjectArray;
+        : Array.Empty<object>();
     }
 
     private PackedTuple(PackedTuple origin)
@@ -137,7 +135,7 @@ private PackedTuple(PackedTuple origin)
       Values = (long[]) origin.Values.Clone();
       Objects = PackedDescriptor.ObjectsLength > 0
         ? (object[]) origin.Objects.Clone()
-        : EmptyObjectArray;
+        : Array.Empty<object>();
     }
   }
 }
diff --git a/Orm/Xtensive.Orm/Tuples/Tuple.cs b/Orm/Xtensive.Orm/Tuples/Tuple.cs
@@ -111,13 +111,13 @@ public T GetValue<T>(int fieldIndex, out TupleFieldState fieldState)
       var isNullable = null==default(T); // Is nullable value type or class
 
       if (this is PackedTuple packedTuple) {
-        ref var descriptor = ref packedTuple.PackedDescriptor.FieldDescriptors[fieldIndex];
+        ref readonly var descriptor = ref packedTuple.PackedDescriptor.FieldDescriptors[fieldIndex];
         return descriptor.Accessor.GetValue<T>(packedTuple, descriptor, isNullable, out fieldState);
       }
 
       var mappedContainer = GetMappedContainer(fieldIndex, false);
       if (mappedContainer.First is PackedTuple mappedTuple) {
-        ref var descriptor = ref mappedTuple.PackedDescriptor.FieldDescriptors[mappedContainer.Second];
+        ref readonly var descriptor = ref mappedTuple.PackedDescriptor.FieldDescriptors[mappedContainer.Second];
         return descriptor.Accessor.GetValue<T>(mappedTuple, descriptor, isNullable, out fieldState);
       }
 
@@ -186,14 +186,14 @@ public void SetValue<T>(int fieldIndex, T fieldValue)
       var isNullable = null==default(T); // Is nullable value type or class
 
       if (this is PackedTuple packedTuple) {
-        ref var descriptor = ref packedTuple.PackedDescriptor.FieldDescriptors[fieldIndex];
+        ref readonly var descriptor = ref packedTuple.PackedDescriptor.FieldDescriptors[fieldIndex];
         descriptor.Accessor.SetValue(packedTuple, descriptor, isNullable, fieldValue);
         return;
       }
 
       var mappedContainer = GetMappedContainer(fieldIndex, true);
       if (mappedContainer.First is PackedTuple mappedTuple) {
-        ref var descriptor = ref mappedTuple.PackedDescriptor.FieldDescriptors[mappedContainer.Second];
+        ref readonly var descriptor = ref mappedTuple.PackedDescriptor.FieldDescriptors[mappedContainer.Second];
         descriptor.Accessor.SetValue(mappedTuple, descriptor, isNullable, fieldValue);
         return;
       }
diff --git a/Orm/Xtensive.Orm/Tuples/TupleExtensions.cs b/Orm/Xtensive.Orm/Tuples/TupleExtensions.cs
@@ -96,13 +96,12 @@ public static void CopyTo(this Tuple source, Tuple target)
     /// Negative value in this map means "skip this element".</param>
     public static void CopyTo(this Tuple source, Tuple target, IReadOnlyList<int> map)
     {
-      var packedSource = source as PackedTuple;
-      var packedTarget = target as PackedTuple;
-
-      if (packedSource!=null && packedTarget!=null)
+      if (source is PackedTuple packedSource && target is PackedTuple packedTarget) {
         CopyTupleWithMappingFast(packedSource, packedTarget, map);
-      else
+      }
+      else {
         CopyTupleWithMappingSlow(source, target, map);
+      }
     }
 
     /// <summary>
@@ -120,20 +119,18 @@ public static void CopyTo(this Tuple[] sources, Tuple target, Pair<int, int>[] m
       var packedSources = new PackedTuple[sources.Length];
 
       for (int i = 0; i < sources.Length; i++) {
-        var packedSource = sources[i] as PackedTuple;
-        if (packedSource==null) {
+        if (sources[i] is PackedTuple packedSource) {
+          packedSources[i] = packedSource;
+        }
+        else {
           haveSlowSource = true;
           break;
         }
-        packedSources[i] = packedSource;
       }
 
-      if (!haveSlowSource) {
-        var packedTarget = target as PackedTuple;
-        if (packedTarget!=null) {
-          CopyTupleArrayWithMappingFast(packedSources, packedTarget, map);
-          return;
-        }
+      if (!haveSlowSource && target is PackedTuple packedTarget) {
+        CopyTupleArrayWithMappingFast(packedSources, packedTarget, map);
+        return;
       }
 
       CopyTupleArrayWithMappingSlow(sources, target, map);
@@ -154,20 +151,18 @@ public static void CopyTo(this FixedList3<Tuple> sources, Tuple target, Pair<int
       var packedSources = new FixedList3<PackedTuple>();
 
       for (int i = 0; i < sources.Count; i++) {
-        var packedSource = sources[i] as PackedTuple;
-        if (packedSource==null) {
+        if (sources[i] is PackedTuple packedSource) {
+          packedSources.Push(packedSource);
+        }
+        else {
           haveSlowSource = true;
           break;
         }
-        packedSources.Push(packedSource);
       }
 
-      if (!haveSlowSource) {
-        var packedTarget = target as PackedTuple;
-        if (packedTarget!=null) {
-          Copy3TuplesWithMappingFast(packedSources, packedTarget, map);
-          return;
-        }
+      if (!haveSlowSource && target is PackedTuple packedTarget) {
+        Copy3TuplesWithMappingFast(packedSources, packedTarget, map);
+        return;
       }
 
       Copy3TuplesWithMappingSlow(sources, target, map);
@@ -185,7 +180,7 @@ public static void CopyTo(this FixedList3<Tuple> sources, Tuple target, Pair<int
     /// <returns></returns>
     public static Tuple Combine(this Tuple left, Tuple right)
     {
-      var transform = new CombineTransform(false, new[] {left.Descriptor, right.Descriptor});
+      var transform = new CombineTransform(false, new[] { left.Descriptor, right.Descriptor });
       return transform.Apply(TupleTransformType.TransformedTuple, left, right);
     }
 
@@ -229,30 +224,30 @@ public static Tuple GetSegment(this Tuple tuple, in Segment<int> segment)
     /// <exception cref="ArgumentException">Tuple descriptors mismatch.</exception>
     public static void MergeWith(this Tuple origin, Tuple difference, int startIndex, int length, MergeBehavior behavior)
     {
-      if (difference==null)
+      if (difference == null)
         return;
-      if (origin.Descriptor!=difference.Descriptor)
+      if (origin.Descriptor != difference.Descriptor)
         throw new ArgumentException(string.Format(Strings.ExInvalidTupleDescriptorExpectedDescriptorIs, origin.Descriptor), "difference");
 
       var packedOrigin = origin as PackedTuple;
       var packedDifference = difference as PackedTuple;
-      var useFast = packedOrigin!=null && packedDifference!=null;
+      var useFast = packedOrigin != null && packedDifference != null;
 
       switch (behavior) {
-      case MergeBehavior.PreferOrigin:
-        if (useFast)
-          MergeTuplesPreferOriginFast(packedOrigin, packedDifference, startIndex, length);
-        else
-          MergeTuplesPreferOriginSlow(origin, difference, startIndex, length);
-        break;
-      case MergeBehavior.PreferDifference:
-        if (useFast)
-          PartiallyCopyTupleFast(packedDifference, packedOrigin, startIndex, startIndex, length);
-        else
-          PartiallyCopyTupleSlow(difference, origin, startIndex, startIndex, length);
-        break;
-      default:
-        throw new ArgumentOutOfRangeException("behavior");
+        case MergeBehavior.PreferOrigin:
+          if (useFast)
+            MergeTuplesPreferOriginFast(packedOrigin, packedDifference, startIndex, length);
+          else
+            MergeTuplesPreferOriginSlow(origin, difference, startIndex, length);
+          break;
+        case MergeBehavior.PreferDifference:
+          if (useFast)
+            PartiallyCopyTupleFast(packedDifference, packedOrigin, startIndex, startIndex, length);
+          else
+            PartiallyCopyTupleSlow(difference, origin, startIndex, startIndex, length);
+          break;
+        default:
+          throw new ArgumentOutOfRangeException("behavior");
       }
     }
 
@@ -338,7 +333,7 @@ public static void MergeWith(this Tuple origin, Tuple difference)
     /// as the specified <paramref name="source"/> tuple.</returns>
     public static RegularTuple ToRegular(this Tuple source)
     {
-      if (source==null)
+      if (source == null)
         return null;
       var result = Tuple.Create(source.Descriptor);
       source.CopyTo(result);
@@ -353,7 +348,7 @@ public static RegularTuple ToRegular(this Tuple source)
     /// <returns>Read-only version of <paramref name="source"/> tuple.</returns>
     public static Tuple ToReadOnly(this Tuple source, TupleTransformType transformType)
     {
-      if (source==null)
+      if (source == null)
         return null;
       return ReadOnlyTransform.Instance.Apply(transformType, source);
     }
@@ -365,7 +360,7 @@ public static Tuple ToReadOnly(this Tuple source, TupleTransformType transformTy
     /// <returns>Fast read-only version of <paramref name="source"/> tuple.</returns>
     public static Tuple ToFastReadOnly(this Tuple source)
     {
-      if (source==null) {
+      if (source == null) {
         return null;
       }
 
@@ -386,14 +381,16 @@ public static BitArray GetFieldStateMap(this Tuple target, TupleFieldState reque
       var result = new BitArray(count);
 
       switch (requestedState) {
-      case TupleFieldState.Default:
-        for (int i = 0; i < count; i++)
-          result[i] = target.GetFieldState(i)==0;
-        break;
-      default:
-        for (int i = 0; i < count; i++)
-          result[i] = (requestedState & target.GetFieldState(i)) != 0;
-        break;
+        case TupleFieldState.Default:
+          for (int i = 0; i < count; i++) {
+            result[i] = target.GetFieldState(i) == 0;
+          }
+          break;
+        default:
+          for (int i = 0; i < count; i++) {
+            result[i] = (requestedState & target.GetFieldState(i)) != 0;
+          }
+          break;
       }
       return result;
     }
@@ -407,7 +404,7 @@ public static BitArray GetFieldStateMap(this Tuple target, TupleFieldState reque
     public static void Initialize(this Tuple target, BitArray nullableMap)
     {
       var descriptor = target.Descriptor;
-      if (descriptor.Count!=nullableMap.Count)
+      if (descriptor.Count != nullableMap.Count)
         throw new ArgumentException(String.Format(Strings.ExInvalidFieldMapSizeExpectedX, descriptor.Count));
 
       for (int i = 0; i < target.Count; i++) {
@@ -434,8 +431,8 @@ private static void CopyValue(Tuple source, int sourceIndex, Tuple target, int t
 
     private static void CopyPackedValue(PackedTuple source, int sourceIndex, PackedTuple target, int targetIndex)
     {
-      ref var sourceDescriptor = ref source.PackedDescriptor.FieldDescriptors[sourceIndex];
-      ref var targetDescriptor = ref target.PackedDescriptor.FieldDescriptors[targetIndex];
+      ref readonly var sourceDescriptor = ref source.PackedDescriptor.FieldDescriptors[sourceIndex];
+      ref readonly var targetDescriptor = ref target.PackedDescriptor.FieldDescriptors[targetIndex];
 
       var fieldState = source.GetFieldState(sourceDescriptor);
       if (!fieldState.IsAvailable()) {
