// This method gets the runtime information for a given type or property.
// The runtime information consists of the following:
// - class type,
// - runtime type,
// - element type (if the type is a collection),
// - the converter (either native or custom), if one exists.
public static JsonConverter GetConverter(
Type type,
Type?parentClassType,
PropertyInfo?propertyInfo,
out Type runtimeType,
JsonSerializerOptions options)
{
Debug.Assert(type != null);
ValidateType(type, parentClassType, propertyInfo, options);
JsonConverter converter = options.DetermineConverter(parentClassType, type, propertyInfo) !;
// The runtimeType is the actual value being assigned to the property.
// There are three types to consider for the runtimeType:
// 1) The declared type (the actual property type).
// 2) The converter.TypeToConvert (the T value that the converter supports).
// 3) The converter.RuntimeType (used with interfaces such as IList).
Type converterRuntimeType = converter.RuntimeType;
if (type == converterRuntimeType)
{
runtimeType = type;
}
else
{
if (type.IsInterface)
{
runtimeType = converterRuntimeType;
}
else if (converterRuntimeType.IsInterface)
{
runtimeType = type;
}
else
{
// Use the most derived version from the converter.RuntimeType or converter.TypeToConvert.
if (type.IsAssignableFrom(converterRuntimeType))
{
runtimeType = converterRuntimeType;
}
else if (converterRuntimeType.IsAssignableFrom(type) || converter.TypeToConvert.IsAssignableFrom(type))
{
runtimeType = type;
}
else
{
runtimeType = default !;
