PageDeserializer.cs

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using Fauna.Mapping;
using Fauna.Types;
 
namespace Fauna.Serialization;
 
internal class PageDeserializer<T> : BaseDeserializer<Page<T>>
{
    private IDeserializer<List<T>> _dataDeserializer;
 
    public PageDeserializer(IDeserializer<T> elemDeserializer)
    {
        _dataDeserializer = new ListDeserializer<T>(elemDeserializer);
    }
 
    public override Page<T> Deserialize(MappingContext context, ref Utf8FaunaReader reader)
    {
        var endToken = reader.CurrentTokenType switch
        {
            TokenType.StartPage => TokenType.EndPage,
            TokenType.StartObject => TokenType.EndObject,
            var other =>
                throw new SerializationException(
                    $"Unexpected token while deserializing into {typeof(Page<T>)}: {other}"),
        };
 
        List<T>? data = null;
        string? after = null;
 
        while (reader.Read() && reader.CurrentTokenType != endToken)
        {
            var fieldName = reader.GetString()!;
            reader.Read();
 
            switch (fieldName)
            {
                case "data":
                    data = _dataDeserializer.Deserialize(context, ref reader);
                    break;
                case "after":
                    after = reader.GetString()!;
                    break;
            }
        }
 
        if (data is null)
            throw new SerializationException($"No page data found while deserializing into {typeof(Page<T>)}");
 
        return new Page<T>(data!, after);
    }
}