/// <inheritdoc/>
public virtual bool Deserialize(IParser reader, Type expectedType, Func <IParser, Type, object> nestedObjectDeserializer, out object value)
{
value = null;
if (!reader.Accept(out MappingStart mapping))
{
return(false);
}
if (expectedType.IsInterface ||
!expectedType.IsAbstract ||
!expectedType.TryGetCustomAttribute(out DiscriminatorAttribute discriminatorAttribute))
{
return(this.Inner.Deserialize(reader, expectedType, nestedObjectDeserializer, out value));
}
if (!this.Resolvers.TryGetValue(expectedType, out AbstractTypeResolver resolver))
{
resolver = new AbstractTypeResolver(expectedType);
this.Resolvers.Add(expectedType, resolver);
}
ParsingEventStream stream = ParsingEventStream.Create(reader);
if (!resolver.TryResolve(stream, out Type concreteType))
{
throw new NullReferenceException($"Failed to resolve the concrete type for the abstract type '{expectedType.Name}'");
}
stream.Reset();
return(this.Inner.Deserialize(stream, concreteType, nestedObjectDeserializer, out value));
}
/// <summary>
/// Attempts to find the specified mapping entry
/// </summary>
/// <param name="parser">The <see cref="ParsingEventStream"/> to search</param>
/// <param name="selector">A predicate <see cref="Func{T, TResult}"/> used to search the <see cref="ParsingEventStream"/> for a specific <see cref="ParsingEvent"/></param>
/// <param name="key">The key of the matching <see cref="Scalar"/></param>
/// <param name="value">The matching <see cref="Scalar"/>'s <see cref="ParsingEvent"/> </param>
/// <returns>A boolean indicating whether or not the specified mapping entry could be found</returns>
public static bool TryFindMappingEntry(this ParsingEventStream parser, Func <Scalar, bool> selector, out Scalar key, out ParsingEvent value)
{
parser.Consume <MappingStart>();
do
{
switch (parser.Current)
{
case Scalar scalar:
var keyMatched = selector(scalar);
parser.MoveNext();
if (keyMatched)
{
value = parser.Current;
key = scalar;
return(true);
}
parser.SkipThisAndNestedEvents();
break;
case MappingStart or SequenceStart:
parser.SkipThisAndNestedEvents();
break;
default:
parser.MoveNext();
break;
}
}while (parser.Current is not null);
key = null;
value = null;
return(false);
}
/// <summary>
/// Attempts to resolve the abstract type's implementation based on the specified <see cref="ParsingEventStream"/>
/// </summary>
/// <param name="stream">The <see cref="ParsingEventStream"/> to use to resolve the implementation type</param>
/// <param name="implementationType">The resulting implementation type</param>
/// <returns>A boolean indicating whether or not the implementation type could be resolved thanks to the specified <see cref="ParsingEventStream"/></returns>
public bool TryResolve(ParsingEventStream stream, out Type implementationType)
{
implementationType = null;
if (stream.TryFindMappingEntry(scalar =>
{
return(string.Equals(scalar.Value, this.DiscriminatorProperty.Name, StringComparison.InvariantCultureIgnoreCase));
}, out Scalar key, out ParsingEvent value))
{
if (value is Scalar valueScalar)
{
return(this.TypeMappings.TryGetValue(valueScalar.Value.ToLower(), out implementationType));
}
}
return(false);
}