Adding Half type support for SqlLite

src/EFCore.Relational/Storage/HalfTypeMapping.cs

@@ -0,0 +1,65 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore.Storage.Json;
+
+namespace Microsoft.EntityFrameworkCore.Storage
+{
+    /// <summary>
+    ///     <para>
+    ///         Represents the mapping between a .NET <see cref="Half" /> type and a database type.
+    ///     </para>
+    ///     <para>
+    ///         This type is typically used by database providers (and other extensions). It is generally
+    ///         not used in application code.
+    ///     </para>
+    /// </summary>
+    /// <remarks>
+    ///     See <see href="https://aka.ms/efcore-docs-providers">Implementation of database providers and extensions</see>
+    ///     for more information and examples.
+    /// </remarks>
+    public class HalfTypeMapping : RelationalTypeMapping
+    {
+        /// <summary>
+        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        public static HalfTypeMapping Default { get; } = new("REAL");
+
+        /// <summary>
+        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        public HalfTypeMapping(
+            string storeType,
+            DbType? dbType = System.Data.DbType.Single)
+            : this(new RelationalTypeMappingParameters(
+                new CoreTypeMappingParameters(
+                    typeof(Half), jsonValueReaderWriter: JsonHalfReaderWriter.Instance),
+                storeType,
+                dbType: dbType))
+        {
+        }
+
+        /// <summary>
+        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        protected HalfTypeMapping(RelationalTypeMappingParameters parameters) : base(parameters) { }
+
+        /// <inheritdoc/>
+        protected override RelationalTypeMapping Clone(RelationalTypeMappingParameters parameters) => new HalfTypeMapping(parameters);
+    }
+}

src/EFCore.Sqlite.Core/Scaffolding/Internal/SqliteDatabaseModelFactory.cs

@@ -87,6 +87,8 @@ public class SqliteDatabaseModelFactory : DatabaseModelFactory
 
     private static readonly HashSet<string> _floatTypes = new(StringComparer.OrdinalIgnoreCase) { "SINGLE" };
 
+    private static readonly HashSet<string> _halfTypes = new(StringComparer.OrdinalIgnoreCase) { "HALF" };
+
     private static readonly HashSet<string> _decimalTypes = new(StringComparer.OrdinalIgnoreCase) { "DECIMAL" };
 
     private static readonly HashSet<string> _ushortTypes = new(StringComparer.OrdinalIgnoreCase)
@@ -127,6 +129,7 @@ public class SqliteDatabaseModelFactory : DatabaseModelFactory
         .Concat(_shortTypes.Select(t => KeyValuePair.Create(t, typeof(short))))
         .Concat(_sbyteTypes.Select(t => KeyValuePair.Create(t, typeof(sbyte))))
         .Concat(_floatTypes.Select(t => KeyValuePair.Create(t, typeof(float))))
+        .Concat(_halfTypes.Select(t => KeyValuePair.Create(t, typeof(Half))))
         .Concat(_decimalTypes.Select(t => KeyValuePair.Create(t, typeof(decimal))))
         .Concat(_timeOnlyTypes.Select(t => KeyValuePair.Create(t, typeof(TimeOnly))))
         .Concat(_ushortTypes.Select(t => KeyValuePair.Create(t, typeof(ushort))))
@@ -811,6 +814,19 @@ protected virtual void InferClrTypes(DbConnection connection, DatabaseTable tabl
                     _logger.OutOfRangeWarning(column.Name, table.Name, "float");
                 }
 
+                if (_halfTypes.Contains(baseColumnType))
+                {
+                    if (min >= (double)Half.MinValue
+                        && max <= (double)Half.MaxValue)
+                    {
+                        column["ClrType"] = typeof(Half);
+
+                        continue;
+                    }
+
+                    _logger.OutOfRangeWarning(column.Name, table.Name, "Half");
+                }
+
                 if (_decimalTypes.Contains(baseColumnType))
                 {
                     column["ClrType"] = typeof(decimal);

src/EFCore.Sqlite.Core/Storage/Internal/SqliteTypeMappingSource.cs

@@ -82,6 +82,9 @@ private static readonly HashSet<string> SpatialiteTypes
         { typeof(decimal), SqliteDecimalTypeMapping.Default },
         { typeof(double), Real },
         { typeof(float), new FloatTypeMapping(RealTypeName) },
+#if NET5_0_OR_GREATER
+        { typeof(Half), new HalfTypeMapping(RealTypeName) },
+#endif
         { typeof(Guid), SqliteGuidTypeMapping.Default },
         { typeof(JsonElement), SqliteJsonTypeMapping.Default }
     };

src/EFCore.Sqlite.Core/Storage/Internal/SqlliteHalfTypeMapping.cs

@@ -0,0 +1,65 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Data;
+
+namespace Microsoft.EntityFrameworkCore.Sqlite.Storage.Internal
+{
+    /// <summary>
+    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+    ///     any release. You should only use it directly in your code with extreme caution and knowing that
+    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+    /// </summary>
+    public class SqlliteHalfTypeMapping : HalfTypeMapping
+    {
+        /// <summary>
+        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        public static new SqlliteHalfTypeMapping Default { get; } = new(SqliteTypeMappingSource.RealTypeName);
+
+        /// <summary>
+        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        public SqlliteHalfTypeMapping(
+            string storeType,
+            DbType? dbType = System.Data.DbType.Single)
+            : base(storeType, dbType)
+        {
+        }
+
+        /// <summary>
+        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        protected SqlliteHalfTypeMapping(RelationalTypeMappingParameters parameters)
+            : base(parameters)
+        {
+        }
+
+        /// <summary>
+        ///     Creates a copy of this mapping.
+        /// </summary>
+        /// <param name="parameters">The parameters for this mapping.</param>
+        /// <returns>The newly created mapping.</returns>
+        protected override RelationalTypeMapping Clone(RelationalTypeMappingParameters parameters)
+            => new SqlliteHalfTypeMapping(parameters);
+
+        /// <summary>
+        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        protected override string GenerateNonNullSqlLiteral(object value)
+            => new DoubleTypeMapping(StoreType).GenerateSqlLiteral((double)(Half)value);
+    }
+}

src/EFCore/Storage/Json/JsonHalfReaderWriter.cs

@@ -0,0 +1,43 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Globalization;
+using System.Text.Json;
+
+namespace Microsoft.EntityFrameworkCore.Storage.Json
+{
+    /// <summary>
+    ///     Reads and writes JSON for Half type values.
+    /// </summary>
+    public sealed class JsonHalfReaderWriter : JsonValueReaderWriter<Half>
+    {
+        private const string HalfFormatConst = "{0:0.0###}";
+
+        private static readonly PropertyInfo InstanceProperty = typeof(JsonHalfReaderWriter).GetProperty(nameof(Instance))!;
+
+        /// <summary>
+        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
+        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        public static JsonHalfReaderWriter Instance { get; } = new();
+
+        private JsonHalfReaderWriter()
+        {
+
+        }
+
+        /// <inheritdoc/>
+        public override Expression ConstructorExpression
+            => Expression.Property(null, InstanceProperty);
+
+        /// <inheritdoc/>
+        public override Half FromJsonTyped(ref Utf8JsonReaderManager manager, object? existingObject = null) =>
+            Half.Parse(manager.CurrentReader.GetString()!, CultureInfo.InvariantCulture);
+
+        /// <inheritdoc/>
+        public override void ToJsonTyped(Utf8JsonWriter writer, Half value) =>
+            writer.WriteStringValue(string.Format(CultureInfo.InvariantCulture, HalfFormatConst, value));
+    }
+}

src/EFCore/Storage/ValueConversion/DoubleToHalfConverter.cs

@@ -0,0 +1,55 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+
+namespace Microsoft.EntityFrameworkCore.Storage.ValueConversion
+{
+    /// <summary>
+    ///     Converts double values to Half type.
+    /// </summary>
+    /// <remarks>
+    ///     See <see href="https://aka.ms/efcore-docs-value-converters">EF Core value converters</see> for more information and examples.
+    /// </remarks>
+    public class DoubleToHalfConverter : ValueConverter<double?, Half?>
+    {
+        private static readonly ConverterMappingHints DefaultHints = new(precision: 4);
+
+        /// <summary>
+        ///     Creates a new instance of this converter.
+        /// </summary>
+        /// <remarks>
+        ///     See <see href="https://aka.ms/efcore-docs-value-converters">EF Core value converters</see> for more information and examples.
+        /// </remarks>
+        public DoubleToHalfConverter()
+            : this(new())
+        {
+
+        }
+
+        /// <summary>
+        ///     Creates a new instance of this converter.
+        /// </summary>
+        /// <remarks>
+        ///     See <see href="https://aka.ms/efcore-docs-value-converters">EF Core value converters</see> for more information and examples.
+        /// </remarks>
+        /// <param name="mappingHints">
+        ///     Hints that can be used by the <see cref="ITypeMappingSource" /> to create data types with appropriate
+        ///     facets for the converted data.
+        /// </param>
+        public DoubleToHalfConverter(ConverterMappingHints mappingHints)
+            : base(
+                  v => (Half)v!,
+                  v => v.HasValue
+                        ? (double)v.Value
+                        : double.MinValue,
+                  DefaultHints.With(mappingHints))
+        {
+        }
+
+        /// <summary>
+        ///     A <see cref="ValueConverterInfo" /> for the default use of this converter.
+        /// </summary>
+        public static ValueConverterInfo DefaultInfo { get; }
+            = new(typeof(double), typeof(Half), i => new DoubleToHalfConverter(i.MappingHints!), DefaultHints);
+    }
+}

src/Microsoft.Data.Sqlite.Core/SqliteValueBinder.cs

@@ -154,6 +154,13 @@ public virtual void Bind()
                 var value1 = (double)(float)value;
                 BindDouble(value1);
             }
+#if NET5_0_OR_GREATER
+            else if (type == typeof(Half))
+            {
+                var value1 = (double)(Half)value;
+                BindDouble(value1);
+            }
+#endif
             else if (type == typeof(Guid))
             {
                 var guid = (Guid)value;
@@ -245,6 +252,9 @@ public virtual void Bind()
                 { typeof(decimal), SqliteType.Text },
                 { typeof(double), SqliteType.Real },
                 { typeof(float), SqliteType.Real },
+#if NET5_0_OR_GREATER
+                { typeof(Half), SqliteType.Real },
+#endif
                 { typeof(Guid), SqliteType.Text },
                 { typeof(int), SqliteType.Integer },
                 { typeof(long), SqliteType.Integer },

src/Microsoft.Data.Sqlite.Core/SqliteValueReader.cs

@@ -99,6 +99,11 @@ public virtual double GetDouble(int ordinal)
         public virtual float GetFloat(int ordinal)
             => (float)GetDouble(ordinal);
 
+#if NET5_0_OR_GREATER
+        public virtual Half GetHalf(int ordinal)
+            => (Half)GetDouble(ordinal);
+#endif
+
         public virtual Guid GetGuid(int ordinal)
         {
             var sqliteType = GetSqliteType(ordinal);
@@ -203,6 +208,13 @@ public virtual string GetString(int ordinal)
                 return (T)(object)GetFloat(ordinal);
             }
 
+#if NET5_0_OR_GREATER
+            if (typeof(T) == typeof(Half))
+            {
+                return (T)(object)GetHalf(ordinal);
+            }
+#endif
+
             if (typeof(T) == typeof(Guid))
             {
                 return (T)(object)GetGuid(ordinal);

test/EFCore.Sqlite.Tests/Storage/SqliteTypeMappingSourceTest.cs

@@ -50,6 +50,7 @@ public class SqliteTypeMappingSourceTest : RelationalTypeMappingSourceTestBase
     [InlineData("TEXT", typeof(TimeSpan?), DbType.Time)]
     [InlineData("TEXT", typeof(decimal?), DbType.Decimal)]
     [InlineData("REAL", typeof(float?), DbType.Single)]
+    [InlineData("REAL", typeof(Half?), DbType.Single)]
     [InlineData("REAL", typeof(double?), DbType.Double)]
     [InlineData("INTEGER", typeof(ByteEnum?), DbType.Byte)]
     [InlineData("INTEGER", typeof(ShortEnum?), DbType.Int16)]
@@ -176,6 +177,7 @@ public void Does_mappings_for_store_type(string storeType, Type clrType, DbType?
     [InlineData("REAL", typeof(float), DbType.Single)]
     [InlineData("UNREALISTIC", typeof(float), DbType.Single)]
     [InlineData("RUBBISH", typeof(float), DbType.Single)]
+    [InlineData("RUBBISH", typeof(Half?), DbType.Single)]
     [InlineData("REAL", typeof(double), DbType.Double)]
     [InlineData("UNREALISTIC", typeof(double), DbType.Double)]
     [InlineData("RUBBISH", typeof(double), DbType.Double)]
@@ -304,6 +306,7 @@ public void Does_default_mappings_for_values()
         Assert.Equal("TEXT", CreateRelationalTypeMappingSource(model).GetMappingForValue(1.0m).StoreType);
         Assert.Equal("REAL", CreateRelationalTypeMappingSource(model).GetMappingForValue(1.0).StoreType);
         Assert.Equal("REAL", CreateRelationalTypeMappingSource(model).GetMappingForValue(1.0f).StoreType);
+        Assert.Equal("REAL", CreateRelationalTypeMappingSource(model).GetMappingForValue((Half)1.0).StoreType);
     }
 
     [ConditionalFact]

test/EFCore.Sqlite.Tests/Storage/SqliteTypeMappingTest.cs

@@ -72,6 +72,7 @@ protected override DbCommand CreateTestCommand()
     [InlineData(typeof(SqliteDecimalTypeMapping), typeof(decimal))]
     [InlineData(typeof(SqliteGuidTypeMapping), typeof(Guid))]
     [InlineData(typeof(SqliteULongTypeMapping), typeof(ulong))]
+    [InlineData(typeof(SqlliteHalfTypeMapping), typeof(Half))]
     public override void Create_and_clone_with_converter(Type mappingType, Type type)
         => base.Create_and_clone_with_converter(mappingType, type);