Serializer cleanup

benchmarks/NexusMods.MnemonicDB.Benchmarks/Benchmarks/IndexSegmentABenchmarks.cs

@@ -21,7 +21,7 @@ public IndexSegmentABenchmarks()
         for (int a = 1; a < 100; a++)
         {
             var prefix = new KeyPrefix(EntityId.From(42), AttributeId.From((ushort)a), TxId.From(42), false,
-                ValueTags.Null);
+                ValueTag.Null);
             builder.Add(new Datom(prefix, ReadOnlyMemory<byte>.Empty));
         }
 

benchmarks/NexusMods.MnemonicDB.Benchmarks/Benchmarks/IndexSegmentEBenchmarks.cs

@@ -24,7 +24,7 @@ public IndexSegmentEBenchmarks()
             for (var a = 0; a < 20; a++)
             {
                 builder.Add(new Datom(new KeyPrefix(EntityId.From((ulong)e), AttributeId.From((ushort)a), TxId.From((ulong)(e + a)), false,
-                    ValueTags.Null), ReadOnlyMemory<byte>.Empty));
+                    ValueTag.Null), ReadOnlyMemory<byte>.Empty));
             }
         }
 

src/NexusMods.MnemonicDB.Abstractions/Attribute.cs

@@ -18,15 +18,10 @@ namespace NexusMods.MnemonicDB.Abstractions;
 ///     Interface for a specific attribute
 /// </summary>
 /// <typeparam name="TValueType"></typeparam>
-public abstract partial class Attribute<TValueType, TLowLevelType> : IAttribute<TValueType>
+public abstract class Attribute<TValueType, TLowLevelType> : IAttribute<TValueType>
 {
-    private const int MaxStackAlloc = 128;
-    private static Encoding AsciiEncoding = Encoding.ASCII;
-
-    private static Encoding Utf8Encoding = Encoding.UTF8;
-
     protected Attribute(
-        ValueTags lowLevelType,
+        ValueTag lowLevelType,
         string ns,
         string name,
         bool isIndexed = false,
@@ -44,116 +39,14 @@ protected Attribute(
     /// Converts a high-level value to a low-level value
     /// </summary>
     protected abstract TLowLevelType ToLowLevel(TValueType value);
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(byte value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(ushort value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(uint value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(string value, ValueTags tag, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(ReadOnlySpan<byte> value, ValueTags tag, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + tag + " on attribute " + Id);
-    }
-
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(ulong value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(UInt128 value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(short value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(int value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(long value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(Int128 value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
-    /// <summary>
-    /// Converts a low-level value to a high-level value
-    /// </summary>
-    protected virtual TValueType FromLowLevel(float value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
+
     /// <summary>
-    /// Converts a low-level value to a high-level value
+    /// Converts a high-level value to a low-level value
     /// </summary>
-    protected virtual TValueType FromLowLevel(double value, ValueTags tags, AttributeResolver resolver)
-    {
-        throw new NotSupportedException("Unsupported low-level type " + value + " on attribute " + Id);
-    }
-
+    protected abstract TValueType FromLowLevel(TLowLevelType value, AttributeResolver resolver);
+
     /// <inheritdoc />
-    public ValueTags LowLevelType { get; }
+    public ValueTag LowLevelType { get; }
 
     /// <inheritdoc />
     public Symbol Id { get; }
@@ -174,7 +67,7 @@ protected virtual TValueType FromLowLevel(double value, ValueTags tags, Attribut
     public Type ValueType => typeof(TValueType);
 
     /// <inheritdoc />
-    public bool IsReference => LowLevelType == ValueTags.Reference;
+    public bool IsReference => LowLevelType == ValueTag.Reference;
 
     /// <inheritdoc />
     IReadDatom IAttribute.Resolve(in KeyPrefix prefix, ReadOnlySpan<byte> valueSpan, AttributeResolver resolver)
@@ -198,6 +91,27 @@ public ReadDatom Resolve(in Datom datom, AttributeResolver resolver)
         var prefix = datom.Prefix;
         return new ReadDatom(in prefix, ReadValue(datom.ValueSpan, datom.Prefix.ValueTag, resolver), this);
     }
+
+    /// <summary>
+    /// Reads the high level value from the given span
+    /// </summary>
+    public TValueType ReadValue(ReadOnlySpan<byte> span, ValueTag tag, AttributeResolver resolver)
+    {
+        return FromLowLevel(tag.Read<TLowLevelType>(span), resolver);
+    }
+
+    /// <summary>
+    /// Write a datom for this attribute to the given writer
+    /// </summary>
+    public void Write<TWriter>(EntityId entityId, AttributeCache cache, TValueType value, TxId txId, bool isRetract, TWriter writer)
+        where TWriter : IBufferWriter<byte>
+    {
+        var prefix = new KeyPrefix(entityId, cache.GetAttributeId(Id), txId, isRetract, LowLevelType);
+        var span = writer.GetSpan(KeyPrefix.Size);
+        MemoryMarshal.Write(span, prefix);
+        writer.Advance(KeyPrefix.Size);
+        LowLevelType.Write(ToLowLevel(value), writer);
+    }
 
     /// <summary>
     /// Returns true if the attribute is present on the entity
@@ -216,23 +130,7 @@ public bool IsIn<T>(T entity)
     {
         return entity.IndexSegment.Contains(this);
     }
-
-    /// <inheritdoc />
-    public virtual void Remap(Func<EntityId, EntityId> remapper, Span<byte> valueSpan)
-    {
-        if (LowLevelType == ValueTags.Reference)
-        {
-            var id = MemoryMarshal.Read<EntityId>(valueSpan);
-            var newId = remapper(id);
-            MemoryMarshal.Write(valueSpan, newId);
-        }
-    }
-
-    private void ThrowKeyNotFoundException(EntityId id)
-    {
-        throw new KeyNotFoundException($"Attribute {Id} not found on entity {id}");
-    }
-
+
     /// <summary>
     /// Adds a datom to the active transaction for this entity that adds the given value to this attribute
     /// </summary>
@@ -274,6 +172,9 @@ public override string ToString()
     /// </summary>
     public readonly record struct ReadDatom : IReadDatom
     {
+        /// <summary>
+        /// The key prefix for this datom, contains the E, A, T, IsRetract and ValueTag values for this datom
+        /// </summary>
         public readonly KeyPrefix Prefix;
 
         /// <summary>

src/NexusMods.MnemonicDB.Abstractions/AttributeCache.cs

@@ -64,14 +64,14 @@ public void Reset(IDb db)
         _symbols = newSymbols;
 
         var types = db.Datoms(AttributeDefinition.ValueType);
-        var newTypes = new ValueTags[maxIndex];
+        var newTypes = new ValueTag[maxIndex];
         var newIsReference = new BitArray(maxIndex);
         foreach (var datom in types)
         {
             var id = datom.E.Value;
             var type = AttributeDefinition.ValueType.ReadValue(datom.ValueSpan, datom.Prefix.ValueTag, null!);
             newTypes[id] = type;
-            newIsReference[(int)id] = type == ValueTags.Reference;
+            newIsReference[(int)id] = type == ValueTag.Reference;
         }
         _isReference = newIsReference;
 

src/NexusMods.MnemonicDB.Abstractions/Attributes/CardinalityAttribute.cs

@@ -5,17 +5,11 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// <summary>
 /// Used to mark the cardinality of an attribute in the database
 /// </summary>
-public class CardinalityAttribute(string ns, string name) : ScalarAttribute<Cardinality, byte>(ValueTags.UInt8, ns, name)
+public sealed class CardinalityAttribute(string ns, string name) : ScalarAttribute<Cardinality, byte>(ValueTag.UInt8, ns, name)
 {
     /// <inheritdoc />
-    protected override byte ToLowLevel(Cardinality value)
-    {
-        return (byte)value;
-    }
+    protected override byte ToLowLevel(Cardinality value) => (byte)value;
 
     /// <inheritdoc />
-    protected override Cardinality FromLowLevel(byte value, ValueTags tags, AttributeResolver resolver)
-    {
-        return (Cardinality)value;
-    }
+    protected override Cardinality FromLowLevel(byte value, AttributeResolver resolver) => (Cardinality)value;
 }

src/NexusMods.MnemonicDB.Abstractions/Attributes/CollectionAttribute.cs

@@ -9,7 +9,7 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// <summary>
 /// An attribute that represents a collection of values
 /// </summary>
-public abstract class CollectionAttribute<TValue, TLowLevel>(ValueTags tag, string ns, string name)
+public abstract class CollectionAttribute<TValue, TLowLevel>(ValueTag tag, string ns, string name)
     : Attribute<TValue, TLowLevel>(tag, ns, name, cardinality: Cardinality.Many)
 {
 

src/NexusMods.MnemonicDB.Abstractions/Attributes/MarkerAttribute.cs

@@ -9,13 +9,13 @@ namespace NexusMods.MnemonicDB.Abstractions.Attributes;
 /// </summary>
 /// <param name="ns"></param>
 /// <param name="name"></param>
-public class MarkerAttribute(string ns, string name) : Attribute<Null, Null>(ValueTags.Null, ns, name)
+public class MarkerAttribute(string ns, string name) : Attribute<Null, Null>(ValueTag.Null, ns, name)
 {
     /// <inheritdoc />
-    protected override Null ToLowLevel(Null value)
-    {
-        return value;
-    }
+    protected override Null ToLowLevel(Null value) => value;
+
+    /// <inheritdoc />
+    protected override Null FromLowLevel(Null value, AttributeResolver resolver) => value;
 
     /// <summary>
     /// Returns true if the entity contains the attribute.