nullable IBinarySerializer support

Author: lucasteles

samples/SpaceWar.Shared/Logic/Ship.cs

@@ -33,7 +33,7 @@ public void Serialize(ref readonly BinaryBufferWriter writer)
         writer.Write(in Invincible);
         writer.Write(in Score);
         writer.Write(in Thrust);
-        writer.Write(in Missile);
+        writer.Write(Missile);
 
         // Caution: WriteStruct not normalize endianness
         writer.WriteStruct(in Bullets);

src/Backdash/Serialization/BinaryBufferReader.cs

@@ -337,11 +337,33 @@ public void ReadNumber<T>(ref T? value, bool isUnsigned) where T : unmanaged, IB
     public T? ReadNullableNumber<T>(bool isUnsigned) where T : unmanaged, IBinaryInteger<T> =>
         ReadBoolean() ? ReadNumber<T>(isUnsigned) : null;
 
+    /// <summary>Reads a <see cref="IBinarySerializable"/> <typeparamref name="T"/> from buffer.</summary>
+    /// <typeparam name="T">A value type that implements <see cref="IBinarySerializable"/>.</typeparam>
+    public T? ReadNullable<T>() where T : struct, IBinarySerializable
+    {
+        T? value = new();
+        Read(ref value);
+        return value;
+    }
 
     /// <summary>Reads a <see cref="IBinarySerializable"/> <paramref name="value"/> from buffer.</summary>
     /// <typeparam name="T">A value type that implements <see cref="IBinarySerializable"/>.</typeparam>
     public void Read<T>(ref T value) where T : struct, IBinarySerializable => value.Deserialize(in this);
 
+    /// <summary>Reads a <see cref="IBinarySerializable"/> <typeparamref name="T"/> from buffer.</summary>
+    /// <typeparam name="T">A value type that implements <see cref="IBinarySerializable"/>.</typeparam>
+    public T Read<T>() where T : struct, IBinarySerializable
+    {
+        T value = new();
+        value.Deserialize(in this);
+        return value;
+    }
+
+    /// <summary>Reads a <see cref="IBinarySerializable"/> <paramref name="value"/> from buffer.</summary>
+    /// <typeparam name="T">A value type that implements <see cref="IBinarySerializable"/>.</typeparam>
+    public void Read<T>(ref T? value) where T : struct, IBinarySerializable =>
+        value = ReadBoolean() ? Read<T>() : null;
+
     /// <summary>Reads a span of <see cref="IBinarySerializable"/> <paramref name="values"/> into buffer.</summary>
     /// <typeparam name="T">A list of a value type that implements <see cref="IBinarySerializable"/>.</typeparam>
     public void Read<T>(in Span<T> values) where T : unmanaged, IBinarySerializable

src/Backdash/Serialization/BinaryBufferWriter.cs

@@ -481,10 +481,24 @@ public void Write(in ReadOnlySpan<DateTimeOffset> values)
     /// <summary>Writes a list of bytes of <see cref="DateOnly"/> <paramref name="values"/> into buffer.</summary>
     public void Write(in List<DateOnly> values) => Write(GetListSpan(in values));
 
+    /// <summary>Writes a <see cref="IBinarySerializable"/> <paramref name="value"/> into buffer.</summary>
+    /// <typeparam name="T">A type that implements <see cref="IBinarySerializable"/>.</typeparam>
+    // ReSharper disable once PossiblyImpureMethodCallOnReadonlyVariable
+    public void Write<T>(ref readonly T value) where T : struct, IBinarySerializable => value.Serialize(in this);
+
+    /// <summary>Writes a <see cref="IBinarySerializable"/> <paramref name="value"/> into buffer.</summary>
+    /// <typeparam name="T">A type that implements <see cref="IBinarySerializable"/>.</typeparam>
+    public void Write<T>(ref readonly T? value) where T : struct, IBinarySerializable
+    {
+        Write(value.HasValue);
+        // ReSharper disable once PossiblyImpureMethodCallOnReadonlyVariable
+        if (value.HasValue)
+            Nullable.GetValueRefOrDefaultRef(in value).Serialize(in this);
+    }
 
     /// <summary>Writes a <see cref="IBinarySerializable"/> <paramref name="value"/> into buffer.</summary>
     /// <typeparam name="T">A type that implements <see cref="IBinarySerializable"/>.</typeparam>
-    public void Write<T>(in T value) where T : IBinarySerializable => value.Serialize(in this);
+    public void Write<T>(T value) where T : class, IBinarySerializable => value.Serialize(in this);
 
     /// <summary>Writes span of <see cref="IBinarySerializable"/> <paramref name="values"/> into buffer.</summary>
     /// <typeparam name="T">A type that implements <see cref="IBinarySerializable"/>.</typeparam>

tests/Backdash.Tests/Specs/Unit/Serialization/BinaryBufferReadWriteNullableValues.cs

@@ -306,6 +306,27 @@ public bool UnmanagedStruct(SimpleStructData? value, Endianness endianness)
         return value == read;
     }
 
+    [PropertyTest]
+    public bool SerializableValueType(SimpleStructData? value, SimpleStructData? result, Endianness endianness)
+    {
+        var size = Setup(value, endianness, out var writer);
+
+        writer.Write(in value);
+        writer.WrittenCount.Should().Be(size);
+
+        var reader = GetReader(writer);
+        reader.Read(ref result);
+        reader.ReadCount.Should().Be(size);
+
+        ResetRead();
+        var otherRead = reader.ReadNullable<SimpleStructData>();
+        reader.ReadCount.Should().Be(size);
+        otherRead.Should().Be(result);
+
+        return value == result;
+    }
+
+
     [Collection(SerialCollectionDefinition.Name)]
     public class BinaryIntegerTests
     {

tests/Backdash.Tests/Specs/Unit/Serialization/BinaryBufferReadWriteValueTests.cs

@@ -380,7 +380,7 @@ public bool SerializableObject(SimpleRefData value, SimpleRefData result, Endian
     {
         var size = Setup<SimpleStructData>(endianness, out var writer);
 
-        writer.Write(in value);
+        writer.Write(value);
         writer.WrittenCount.Should().Be(size);
 
         var reader = GetReader(writer);