Remove second type parameter from CastingConverter (#80755)

dotnet · Jan 20, 2023 · a04aaeb · a04aaeb
1 parent 43b8dcf
commit a04aaeb
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Showing 11 changed files with 217 additions and 104 deletions.
diff --git a/...raries/System.Text.Json/src/System/Text/Json/Serialization/Converters/CastingConverter.cs b/...raries/System.Text.Json/src/System/Text/Json/Serialization/Converters/CastingConverter.cs
@@ -2,25 +2,26 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics;
+using System.Runtime.CompilerServices;
 using System.Text.Json.Reflection;
 
 namespace System.Text.Json.Serialization.Converters
 {
     /// <summary>
     /// Converter wrapper which casts SourceType into TargetType
     /// </summary>
-    internal sealed class CastingConverter<T, TSource> : JsonConverter<T>
+    internal sealed class CastingConverter<T> : JsonConverter<T>
     {
-        private readonly JsonConverter<TSource> _sourceConverter;
+        private readonly JsonConverter _sourceConverter;
         internal override Type? KeyType => _sourceConverter.KeyType;
         internal override Type? ElementType => _sourceConverter.ElementType;
 
         public override bool HandleNull { get; }
         internal override bool SupportsCreateObjectDelegate => _sourceConverter.SupportsCreateObjectDelegate;
 
-        internal CastingConverter(JsonConverter<TSource> sourceConverter)
+        internal CastingConverter(JsonConverter sourceConverter, bool handleNull, bool handleNullOnRead, bool handleNullOnWrite)
         {
-            Debug.Assert(typeof(T).IsInSubtypeRelationshipWith(typeof(TSource)));
+            Debug.Assert(typeof(T).IsInSubtypeRelationshipWith(sourceConverter.TypeToConvert));
             Debug.Assert(sourceConverter.SourceConverterForCastingConverter is null, "casting converters should not be layered.");
 
             _sourceConverter = sourceConverter;
@@ -30,83 +31,45 @@ internal CastingConverter(JsonConverter<TSource> sourceConverter)
             CanBePolymorphic = sourceConverter.CanBePolymorphic;
 
             // Ensure HandleNull values reflect the exact configuration of the source converter
-            HandleNullOnRead = sourceConverter.HandleNullOnRead;
-            HandleNullOnWrite = sourceConverter.HandleNullOnWrite;
-            HandleNull = sourceConverter.HandleNull;
+            HandleNullOnRead = handleNullOnRead;
+            HandleNullOnWrite = handleNullOnWrite;
+            HandleNull = handleNull;
         }
 
         internal override JsonConverter? SourceConverterForCastingConverter => _sourceConverter;
 
         public override T? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
-            => CastOnRead(_sourceConverter.Read(ref reader, typeToConvert, options));
+            => JsonSerializer.UnboxOnRead<T>(_sourceConverter.ReadAsObject(ref reader, typeToConvert, options));
 
         public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
-            => _sourceConverter.Write(writer, CastOnWrite(value), options);
+            => _sourceConverter.WriteAsObject(writer, value, options);
 
         internal override bool OnTryRead(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options, scoped ref ReadStack state, out T? value)
         {
-            bool result = _sourceConverter.OnTryRead(ref reader, typeToConvert, options, ref state, out TSource? sourceValue);
-            value = CastOnRead(sourceValue);
+            bool result = _sourceConverter.OnTryReadAsObject(ref reader, typeToConvert, options, ref state, out object? sourceValue);
+            value = JsonSerializer.UnboxOnRead<T>(sourceValue);
             return result;
         }
 
         internal override bool OnTryWrite(Utf8JsonWriter writer, T value, JsonSerializerOptions options, ref WriteStack state)
-            => _sourceConverter.OnTryWrite(writer, CastOnWrite(value), options, ref state);
+            => _sourceConverter.OnTryWriteAsObject(writer, value, options, ref state);
 
         public override T ReadAsPropertyName(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
-            => CastOnRead(_sourceConverter.ReadAsPropertyName(ref reader, typeToConvert, options));
+            => JsonSerializer.UnboxOnRead<T>(_sourceConverter.ReadAsPropertyNameAsObject(ref reader, typeToConvert, options))!;
 
         internal override T ReadAsPropertyNameCore(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
-            => CastOnRead(_sourceConverter.ReadAsPropertyNameCore(ref reader, typeToConvert, options));
+            => JsonSerializer.UnboxOnRead<T>(_sourceConverter.ReadAsPropertyNameCoreAsObject(ref reader, typeToConvert, options))!;
 
         public override void WriteAsPropertyName(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
-            => _sourceConverter.WriteAsPropertyName(writer, CastOnWrite(value), options);
+            => _sourceConverter.WriteAsPropertyNameAsObject(writer, value, options);
 
         internal override void WriteAsPropertyNameCore(Utf8JsonWriter writer, T value, JsonSerializerOptions options, bool isWritingExtensionDataProperty)
-            => _sourceConverter.WriteAsPropertyNameCore(writer, CastOnWrite(value), options, isWritingExtensionDataProperty);
+            => _sourceConverter.WriteAsPropertyNameCoreAsObject(writer, value, options, isWritingExtensionDataProperty);
 
         internal override T ReadNumberWithCustomHandling(ref Utf8JsonReader reader, JsonNumberHandling handling, JsonSerializerOptions options)
-            => CastOnRead(_sourceConverter.ReadNumberWithCustomHandling(ref reader, handling, options));
+            => JsonSerializer.UnboxOnRead<T>(_sourceConverter.ReadNumberWithCustomHandlingAsObject(ref reader, handling, options))!;
 
         internal override void WriteNumberWithCustomHandling(Utf8JsonWriter writer, T value, JsonNumberHandling handling)
-            => _sourceConverter.WriteNumberWithCustomHandling(writer, CastOnWrite(value), handling);
-
-        private static T CastOnRead(TSource? source)
-        {
-            if (default(T) is null && default(TSource) is null && source is null)
-            {
-                return default!;
-            }
-
-            if (source is T t)
-            {
-                return t;
-            }
-
-            HandleFailure(source);
-            return default!;
-
-            static void HandleFailure(TSource? source)
-            {
-                if (source is null)
-                {
-                    ThrowHelper.ThrowInvalidOperationException_DeserializeUnableToAssignNull(typeof(T));
-                }
-                else
-                {
-                    ThrowHelper.ThrowInvalidCastException_DeserializeUnableToAssignValue(typeof(TSource), typeof(T));
-                }
-            }
-        }
-
-        private static TSource CastOnWrite(T source)
-        {
-            if (default(TSource) is not null && default(T) is null && source is null)
-            {
-                ThrowHelper.ThrowJsonException_DeserializeUnableToConvertValue(typeof(TSource));
-            }
-
-            return (TSource)(object?)source!;
-        }
+            => _sourceConverter.WriteNumberWithCustomHandlingAsObject(writer, value, handling);
     }
 }
diff --git a/....Json/src/System/Text/Json/Serialization/Converters/Collection/JsonCollectionConverter.cs b/....Json/src/System/Text/Json/Serialization/Converters/Collection/JsonCollectionConverter.cs
@@ -166,7 +166,7 @@ internal override bool OnTryRead(
                     ResolvePolymorphicConverter(jsonTypeInfo, ref state) is JsonConverter polymorphicConverter)
                 {
                     Debug.Assert(!IsValueType);
-                    bool success = polymorphicConverter.OnTryReadAsObject(ref reader, options, ref state, out object? objectResult);
+                    bool success = polymorphicConverter.OnTryReadAsObject(ref reader, polymorphicConverter.TypeToConvert, options, ref state, out object? objectResult);
                     value = (TCollection)objectResult!;
                     state.ExitPolymorphicConverter(success);
                     return success;

diff --git a/....Json/src/System/Text/Json/Serialization/Converters/Collection/JsonDictionaryConverter.cs b/....Json/src/System/Text/Json/Serialization/Converters/Collection/JsonDictionaryConverter.cs
@@ -190,7 +190,7 @@ internal sealed override bool OnTryRead(
                     ResolvePolymorphicConverter(jsonTypeInfo, ref state) is JsonConverter polymorphicConverter)
                 {
                     Debug.Assert(!IsValueType);
-                    bool success = polymorphicConverter.OnTryReadAsObject(ref reader, options, ref state, out object? objectResult);
+                    bool success = polymorphicConverter.OnTryReadAsObject(ref reader, polymorphicConverter.TypeToConvert, options, ref state, out object? objectResult);
                     value = (TDictionary)objectResult!;
                     state.ExitPolymorphicConverter(success);
                     return success;

diff --git a/....Text.Json/src/System/Text/Json/Serialization/Converters/Object/ObjectDefaultConverter.cs b/....Text.Json/src/System/Text/Json/Serialization/Converters/Object/ObjectDefaultConverter.cs
@@ -107,7 +107,7 @@ internal override bool OnTryRead(ref Utf8JsonReader reader, Type typeToConvert,
                     ResolvePolymorphicConverter(jsonTypeInfo, ref state) is JsonConverter polymorphicConverter)
                 {
                     Debug.Assert(!IsValueType);
-                    bool success = polymorphicConverter.OnTryReadAsObject(ref reader, options, ref state, out object? objectResult);
+                    bool success = polymorphicConverter.OnTryReadAsObject(ref reader, polymorphicConverter.TypeToConvert, options, ref state, out object? objectResult);
                     value = (T)objectResult!;
                     state.ExitPolymorphicConverter(success);
                     return success;

diff --git a/...Json/Serialization/Converters/Object/ObjectWithParameterizedConstructorConverter.Large.cs b/...Json/Serialization/Converters/Object/ObjectWithParameterizedConstructorConverter.Large.cs
@@ -19,7 +19,7 @@ protected sealed override bool ReadAndCacheConstructorArgument(scoped ref ReadSt
             Debug.Assert(jsonParameterInfo.ShouldDeserialize);
             Debug.Assert(jsonParameterInfo.Options != null);
 
-            bool success = jsonParameterInfo.ConverterBase.TryReadAsObject(ref reader, jsonParameterInfo.Options!, ref state, out object? arg);
+            bool success = jsonParameterInfo.ConverterBase.TryReadAsObject(ref reader, TypeToConvert, jsonParameterInfo.Options!, ref state, out object? arg);
 
             if (success && !(arg == null && jsonParameterInfo.IgnoreNullTokensOnRead))
             {

diff --git a/.../Text/Json/Serialization/Converters/Object/ObjectWithParameterizedConstructorConverter.cs b/.../Text/Json/Serialization/Converters/Object/ObjectWithParameterizedConstructorConverter.cs
@@ -137,7 +137,7 @@ internal sealed override bool OnTryRead(ref Utf8JsonReader reader, Type typeToCo
                     ResolvePolymorphicConverter(jsonTypeInfo, ref state) is JsonConverter polymorphicConverter)
                 {
                     Debug.Assert(!IsValueType);
-                    bool success = polymorphicConverter.OnTryReadAsObject(ref reader, options, ref state, out object? objectResult);
+                    bool success = polymorphicConverter.OnTryReadAsObject(ref reader, polymorphicConverter.TypeToConvert, options, ref state, out object? objectResult);
                     value = (T)objectResult!;
                     state.ExitPolymorphicConverter(success);
                     return success;

diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonConverter.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonConverter.cs
@@ -110,6 +110,11 @@ internal virtual JsonTypeInfo CreateCustomJsonTypeInfo(JsonSerializerOptions opt
 
         internal abstract JsonConverter<TTarget> CreateCastingConverter<TTarget>();
 
+        /// <summary>
+        /// Set if this converter is itself a casting converter.
+        /// </summary>
+        internal virtual JsonConverter? SourceConverterForCastingConverter => null;
+
         internal abstract Type? ElementType { get; }
 
         internal abstract Type? KeyType { get; }
@@ -138,15 +143,20 @@ internal static bool ShouldFlush(Utf8JsonWriter writer, ref WriteStack state)
         // This is used internally to quickly determine the type being converted for JsonConverter<T>.
         internal abstract Type TypeToConvert { get; }
 
-        internal abstract bool OnTryReadAsObject(ref Utf8JsonReader reader, JsonSerializerOptions options, scoped ref ReadStack state, out object? value);
-        internal abstract bool TryReadAsObject(ref Utf8JsonReader reader, JsonSerializerOptions options, scoped ref ReadStack state, out object? value);
+        internal abstract object? ReadAsObject(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options);
+        internal abstract bool OnTryReadAsObject(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options, scoped ref ReadStack state, out object? value);
+        internal abstract bool TryReadAsObject(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options, scoped ref ReadStack state, out object? value);
+        internal abstract object? ReadAsPropertyNameAsObject(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options);
+        internal abstract object? ReadAsPropertyNameCoreAsObject(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options);
+        internal abstract object? ReadNumberWithCustomHandlingAsObject(ref Utf8JsonReader reader, JsonNumberHandling handling, JsonSerializerOptions options);
 
+        internal abstract void WriteAsObject(Utf8JsonWriter writer, object? value, JsonSerializerOptions options);
+        internal abstract bool OnTryWriteAsObject(Utf8JsonWriter writer, object? value, JsonSerializerOptions options, ref WriteStack state);
         internal abstract bool TryWriteAsObject(Utf8JsonWriter writer, object? value, JsonSerializerOptions options, ref WriteStack state);
+        internal abstract void WriteAsPropertyNameAsObject(Utf8JsonWriter writer, object? value, JsonSerializerOptions options);
+        internal abstract void WriteAsPropertyNameCoreAsObject(Utf8JsonWriter writer, object? value, JsonSerializerOptions options, bool isWritingExtensionDataProperty);
+        internal abstract void WriteNumberWithCustomHandlingAsObject(Utf8JsonWriter writer, object? value, JsonNumberHandling handling);
 
-        /// <summary>
-        /// Loosely-typed WriteToPropertyName() that forwards to strongly-typed WriteToPropertyName().
-        /// </summary>
-        internal abstract void WriteAsPropertyNameCoreAsObject(Utf8JsonWriter writer, object value, JsonSerializerOptions options, bool isWritingExtensionDataProperty);
 
         // Whether a type (ConverterStrategy.Object) is deserialized using a parameterized constructor.
         internal virtual bool ConstructorIsParameterized { get; }

diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonConverterFactory.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonConverterFactory.cs
@@ -61,8 +61,16 @@ internal JsonConverter GetConverterInternal(Type typeToConvert, JsonSerializerOp
             return converter;
         }
 
+        internal sealed override object? ReadAsObject(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            Debug.Fail("We should never get here.");
+
+            throw new InvalidOperationException();
+        }
+
         internal sealed override bool OnTryReadAsObject(
             ref Utf8JsonReader reader,
+            Type typeToConvert,
             JsonSerializerOptions options,
             scoped ref ReadStack state,
             out object? value)
@@ -74,6 +82,7 @@ internal sealed override bool OnTryReadAsObject(
 
         internal sealed override bool TryReadAsObject(
             ref Utf8JsonReader reader,
+            Type typeToConvert,
             JsonSerializerOptions options,
             scoped ref ReadStack state,
             out object? value)
@@ -83,6 +92,45 @@ internal sealed override bool TryReadAsObject(
             throw new InvalidOperationException();
         }
 
+        internal sealed override object? ReadAsPropertyNameAsObject(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            Debug.Fail("We should never get here.");
+
+            throw new InvalidOperationException();
+        }
+
+        internal sealed override object? ReadAsPropertyNameCoreAsObject(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            Debug.Fail("We should never get here.");
+
+            throw new InvalidOperationException();
+        }
+
+        internal sealed override object? ReadNumberWithCustomHandlingAsObject(ref Utf8JsonReader reader, JsonNumberHandling handling, JsonSerializerOptions options)
+        {
+            Debug.Fail("We should never get here.");
+
+            throw new InvalidOperationException();
+        }
+
+        internal sealed override void WriteAsObject(Utf8JsonWriter writer, object? value, JsonSerializerOptions options)
+        {
+            Debug.Fail("We should never get here.");
+
+            throw new InvalidOperationException();
+        }
+
+        internal sealed override bool OnTryWriteAsObject(
+            Utf8JsonWriter writer,
+            object? value,
+            JsonSerializerOptions options,
+            ref WriteStack state)
+        {
+            Debug.Fail("We should never get here.");
+
+            throw new InvalidOperationException();
+        }
+
         internal sealed override bool TryWriteAsObject(
             Utf8JsonWriter writer,
             object? value,
@@ -94,10 +142,18 @@ internal sealed override bool TryWriteAsObject(
             throw new InvalidOperationException();
         }
 
+        internal sealed override void WriteAsPropertyNameAsObject(Utf8JsonWriter writer, object? value, JsonSerializerOptions options)
+        {
+            Debug.Fail("We should never get here.");
+
+            throw new InvalidOperationException();
+        }
+
         internal sealed override Type TypeToConvert => null!;
 
         internal sealed override void WriteAsPropertyNameCoreAsObject(
-            Utf8JsonWriter writer, object value,
+            Utf8JsonWriter writer,
+            object? value,
             JsonSerializerOptions options,
             bool isWritingExtensionDataProperty)
         {
@@ -106,6 +162,13 @@ internal sealed override void WriteAsPropertyNameCoreAsObject(
             throw new InvalidOperationException();
         }
 
+        internal sealed override void WriteNumberWithCustomHandlingAsObject(Utf8JsonWriter writer, object? value, JsonNumberHandling handling)
+        {
+            Debug.Fail("We should never get here.");
+
+            throw new InvalidOperationException();
+        }
+
         internal sealed override JsonConverter<TTarget> CreateCastingConverter<TTarget>()
         {
             ThrowHelper.ThrowInvalidOperationException_ConverterCanConvertMultipleTypes(typeof(TTarget), this);