68 lines
2.0 KiB
C#
68 lines
2.0 KiB
C#
using System.Text.Json;
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using System.Text.Json.Serialization;
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namespace zero.Stores;
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public abstract class JsonDiscriminatorConverter<T> : JsonConverter<T> where T : class, new()
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{
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Type _type;
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string _discriminatorPropertyName;
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public JsonDiscriminatorConverter(string discriminatorPropertyName) : base()
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{
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_discriminatorPropertyName = discriminatorPropertyName;
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_type = GetType();
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}
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protected abstract Type GetTypeFromDiscriminator(Type requestedType, string discriminator);
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/// <inheritdoc />
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public override bool CanConvert(Type typeToConvert) => typeof(T).IsAssignableFrom(typeToConvert);
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/// <inheritdoc />
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public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
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{
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Utf8JsonReader variantReader = reader;
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string discriminatorValue = null;
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while (variantReader.Read())
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{
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if (variantReader.TokenType == JsonTokenType.PropertyName)
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{
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string property = variantReader.GetString();
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if (property != null && property.Equals(_discriminatorPropertyName, StringComparison.InvariantCultureIgnoreCase))
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{
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variantReader.Read();
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discriminatorValue = variantReader.GetString();
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break;
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}
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}
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}
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Type childType = GetTypeFromDiscriminator(typeToConvert, discriminatorValue);
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Type resolvedType = childType ?? typeToConvert;
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return JsonSerializer.Deserialize(ref reader, resolvedType, CreateOptions(options)) as T;
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}
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/// <inheritdoc />
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public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
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{
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JsonSerializer.Serialize(writer, value, value.GetType(), CreateOptions(options));
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}
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protected virtual JsonSerializerOptions CreateOptions(JsonSerializerOptions baseOptions)
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{
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JsonSerializerOptions newOptions = new(baseOptions);
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JsonConverter toRemove = newOptions.Converters.FirstOrDefault(x => x.GetType() == _type);
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newOptions.Converters.Remove(toRemove);
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return newOptions;
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}
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}
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