private JsonConverter GetConverterFromOptionsOrReflectionConverter(Type typeToConvert)
{
Debug.Assert(typeToConvert != null);
// Priority 1: Attempt to get custom converter from the Converters list.
JsonConverter?converter = GetConverterFromOptions(typeToConvert);
// Priority 2: Attempt to get converter from [JsonConverter] on the type being converted.
if (converter == null)
{
JsonConverterAttribute?converterAttribute = (JsonConverterAttribute?)
GetAttributeThatCanHaveMultiple(typeToConvert, typeof(JsonConverterAttribute));
if (converterAttribute != null)
{
converter = GetConverterFromAttribute(converterAttribute, typeToConvert: typeToConvert, classTypeAttributeIsOn: typeToConvert, memberInfo: null);
}
}
// Priority 3: Attempt to get built-in converter.
converter ??= DefaultJsonTypeInfoResolver.GetDefaultConverter(typeToConvert);
// Allow redirection for generic types or the enum converter.
if (converter is JsonConverterFactory factory)
{
converter = factory.GetConverterInternal(typeToConvert, this);
// A factory cannot return null; GetConverterInternal checked for that.
Debug.Assert(converter != null);
}
Type converterTypeToConvert = converter.TypeToConvert;
if (!converterTypeToConvert.IsAssignableFromInternal(typeToConvert) &&
!typeToConvert.IsAssignableFromInternal(converterTypeToConvert))
{
ThrowHelper.ThrowInvalidOperationException_SerializationConverterNotCompatible(converter.GetType(), typeToConvert);
}
return(converter);
}
internal JsonConverter GetConverterInternal(Type typeToConvert)
{
Debug.Assert(typeToConvert != null);
if (_converters.TryGetValue(typeToConvert, out JsonConverter? converter))
{
Debug.Assert(converter != null);
return(converter);
}
// Priority 1: If there is a JsonSerializerContext, fetch the converter from there.
converter = _context?.GetTypeInfo(typeToConvert)?.PropertyInfoForTypeInfo?.ConverterBase;
// Priority 2: Attempt to get custom converter added at runtime.
// Currently there is not a way at runtime to override the [JsonConverter] when applied to a property.
foreach (JsonConverter item in Converters)
{
if (item.CanConvert(typeToConvert))
{
converter = item;
break;
}
}
// Priority 3: Attempt to get converter from [JsonConverter] on the type being converted.
if (converter == null)
{
JsonConverterAttribute?converterAttribute = (JsonConverterAttribute?)
GetAttributeThatCanHaveMultiple(typeToConvert, typeof(JsonConverterAttribute));
if (converterAttribute != null)
{
converter = GetConverterFromAttribute(converterAttribute, typeToConvert: typeToConvert, classTypeAttributeIsOn: typeToConvert, memberInfo: null);
}
}
// Priority 4: Attempt to get built-in converter.
if (converter == null)
{
if (s_defaultSimpleConverters == null || s_defaultFactoryConverters == null)
{
// (De)serialization using serializer's options-based methods has not yet occurred, so the built-in converters are not rooted.
// Even though source-gen code paths do not call this method <i.e. JsonSerializerOptions.GetConverter(Type)>, we do not root all the
// built-in converters here since we fetch converters for any type included for source generation from the binded context (Priority 1).
Debug.Assert(s_defaultSimpleConverters == null);
Debug.Assert(s_defaultFactoryConverters == null);
ThrowHelper.ThrowNotSupportedException_BuiltInConvertersNotRooted(typeToConvert);
return(null !);
}
if (s_defaultSimpleConverters.TryGetValue(typeToConvert, out JsonConverter? foundConverter))
{
converter = foundConverter;
}
else
{
foreach (JsonConverter item in s_defaultFactoryConverters)
{
if (item.CanConvert(typeToConvert))
{
converter = item;
break;
}
}
// Since the object and IEnumerable converters cover all types, we should have a converter.
Debug.Assert(converter != null);
}
}
// Allow redirection for generic types or the enum converter.
if (converter is JsonConverterFactory factory)
{
converter = factory.GetConverterInternal(typeToConvert, this);
// A factory cannot return null; GetConverterInternal checked for that.
Debug.Assert(converter != null);
}
Type converterTypeToConvert = converter.TypeToConvert;
if (!converterTypeToConvert.IsAssignableFromInternal(typeToConvert) &&
!typeToConvert.IsAssignableFromInternal(converterTypeToConvert))
{
ThrowHelper.ThrowInvalidOperationException_SerializationConverterNotCompatible(converter.GetType(), typeToConvert);
}
// Only cache the value once (de)serialization has occurred since new converters can be added that may change the result.
if (_haveTypesBeenCreated)
{
// A null converter is allowed here and cached.
// Ignore failure case here in multi-threaded cases since the cached item will be equivalent.
_converters.TryAdd(typeToConvert, converter);
}
return(converter);
}
/// <summary>
/// Returns the converter for the specified type.
/// </summary>
/// <param name="typeToConvert">The type to return a converter for.</param>
/// <returns>
/// The first converter that supports the given type, or null if there is no converter.
/// </returns>
public JsonConverter?GetConverter(Type typeToConvert)
{
if (_converters.TryGetValue(typeToConvert, out JsonConverter? converter))
{
return(converter);
}
// Priority 2: Attempt to get custom converter added at runtime.
// Currently there is not a way at runtime to overide the [JsonConverter] when applied to a property.
foreach (JsonConverter item in Converters)
{
if (item.CanConvert(typeToConvert))
{
converter = item;
break;
}
}
// Priority 3: Attempt to get converter from [JsonConverter] on the type being converted.
if (converter == null)
{
JsonConverterAttribute?converterAttribute = (JsonConverterAttribute?)
GetAttributeThatCanHaveMultiple(typeToConvert, typeof(JsonConverterAttribute));
if (converterAttribute != null)
{
converter = GetConverterFromAttribute(converterAttribute, typeToConvert: typeToConvert, classTypeAttributeIsOn: typeToConvert, propertyInfo: null);
}
}
// Priority 4: Attempt to get built-in converter.
if (converter == null)
{
if (s_defaultSimpleConverters.TryGetValue(typeToConvert, out JsonConverter? foundConverter))
{
converter = foundConverter;
}
else
{
foreach (JsonConverter item in s_defaultFactoryConverters)
{
if (item.CanConvert(typeToConvert))
{
converter = item;
break;
}
}
}
}
// Allow redirection for generic types or the enum converter.
if (converter is JsonConverterFactory factory)
{
converter = factory.GetConverterInternal(typeToConvert, this);
// Allow null converters from the factory. This will result in a NotSupportedException later
// and with a nice exception that indicates the parent type.
}
if (converter != null)
{
Type converterTypeToConvert = converter.TypeToConvert !;
if (!converterTypeToConvert.IsAssignableFrom(typeToConvert) &&
!typeToConvert.IsAssignableFrom(converterTypeToConvert))
{
ThrowHelper.ThrowInvalidOperationException_SerializationConverterNotCompatible(converter.GetType(), typeToConvert);
}
}
// Only cache the value once (de)serialization has occurred since new converters can be added that may change the result.
if (_haveTypesBeenCreated)
{
// A null converter is allowed here and cached.
// Ignore failure case here in multi-threaded cases since the cached item will be equivalent.
_converters.TryAdd(typeToConvert, converter);
}
return(converter);
}
