| | | 1 | | // Licensed to the .NET Foundation under one or more agreements. |
| | | 2 | | // The .NET Foundation licenses this file to you under the MIT license. |
| | | 3 | | |
| | | 4 | | using System.Text.Json.Serialization.Metadata; |
| | | 5 | | |
| | | 6 | | namespace System.Text.Json.Serialization.Converters |
| | | 7 | | { |
| | | 8 | | internal sealed class NullableConverter<T> : JsonConverter<T?> where T : struct // Do not rename FQN (legacy schema |
| | | 9 | | { |
| | 0 | 10 | | internal override Type? ElementType => typeof(T); |
| | 0 | 11 | | internal override JsonConverter? NullableElementConverter => _elementConverter; |
| | 0 | 12 | | public override bool HandleNull => true; |
| | 0 | 13 | | internal override bool CanPopulate => _elementConverter.CanPopulate; |
| | 0 | 14 | | internal override bool ConstructorIsParameterized => _elementConverter.ConstructorIsParameterized; |
| | | 15 | | |
| | | 16 | | // It is possible to cache the underlying converter since this is an internal converter and |
| | | 17 | | // an instance is created only once for each JsonSerializerOptions instance. |
| | | 18 | | private readonly JsonConverter<T> _elementConverter; // Do not rename (legacy schema generation) |
| | | 19 | | |
| | 0 | 20 | | public NullableConverter(JsonConverter<T> elementConverter) |
| | 0 | 21 | | { |
| | 0 | 22 | | _elementConverter = elementConverter; |
| | 0 | 23 | | IsInternalConverter = elementConverter.IsInternalConverter; |
| | 0 | 24 | | IsInternalConverterForNumberType = elementConverter.IsInternalConverterForNumberType; |
| | 0 | 25 | | ConverterStrategy = elementConverter.ConverterStrategy; |
| | 0 | 26 | | SupportsMultipleTokenTypes = elementConverter.SupportsMultipleTokenTypes; |
| | 0 | 27 | | RequiresReadAhead = elementConverter.RequiresReadAhead; |
| | 0 | 28 | | } |
| | | 29 | | |
| | | 30 | | internal override bool OnTryRead(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options, s |
| | 0 | 31 | | { |
| | 0 | 32 | | if (!state.IsContinuation && reader.TokenType == JsonTokenType.Null) |
| | 0 | 33 | | { |
| | 0 | 34 | | value = null; |
| | 0 | 35 | | return true; |
| | | 36 | | } |
| | | 37 | | |
| | 0 | 38 | | JsonTypeInfo previousTypeInfo = state.Current.JsonTypeInfo; |
| | 0 | 39 | | state.Current.JsonTypeInfo = state.Current.JsonTypeInfo.ElementTypeInfo!; |
| | 0 | 40 | | if (_elementConverter.OnTryRead(ref reader, typeof(T), options, ref state, out T element)) |
| | 0 | 41 | | { |
| | 0 | 42 | | value = element; |
| | 0 | 43 | | state.Current.JsonTypeInfo = previousTypeInfo; |
| | 0 | 44 | | return true; |
| | | 45 | | } |
| | | 46 | | |
| | 0 | 47 | | state.Current.JsonTypeInfo = previousTypeInfo; |
| | 0 | 48 | | value = null; |
| | 0 | 49 | | return false; |
| | 0 | 50 | | } |
| | | 51 | | |
| | | 52 | | internal override bool OnTryWrite(Utf8JsonWriter writer, T? value, JsonSerializerOptions options, ref WriteStack |
| | 0 | 53 | | { |
| | 0 | 54 | | if (value is null) |
| | 0 | 55 | | { |
| | 0 | 56 | | writer.WriteNullValue(); |
| | 0 | 57 | | return true; |
| | | 58 | | } |
| | | 59 | | |
| | 0 | 60 | | state.Current.JsonPropertyInfo = state.Current.JsonTypeInfo.ElementTypeInfo!.PropertyInfoForTypeInfo; |
| | 0 | 61 | | return _elementConverter.TryWrite(writer, value.Value, options, ref state); |
| | 0 | 62 | | } |
| | | 63 | | |
| | | 64 | | public override T? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) |
| | 0 | 65 | | { |
| | 0 | 66 | | if (reader.TokenType == JsonTokenType.Null) |
| | 0 | 67 | | { |
| | 0 | 68 | | return null; |
| | | 69 | | } |
| | | 70 | | |
| | 0 | 71 | | T value = _elementConverter.Read(ref reader, typeof(T), options); |
| | 0 | 72 | | return value; |
| | 0 | 73 | | } |
| | | 74 | | |
| | | 75 | | public override void Write(Utf8JsonWriter writer, T? value, JsonSerializerOptions options) |
| | 0 | 76 | | { |
| | 0 | 77 | | if (value is null) |
| | 0 | 78 | | { |
| | 0 | 79 | | writer.WriteNullValue(); |
| | 0 | 80 | | } |
| | | 81 | | else |
| | 0 | 82 | | { |
| | 0 | 83 | | _elementConverter.Write(writer, value.Value, options); |
| | 0 | 84 | | } |
| | 0 | 85 | | } |
| | | 86 | | |
| | | 87 | | internal override T? ReadNumberWithCustomHandling(ref Utf8JsonReader reader, JsonNumberHandling numberHandling, |
| | 0 | 88 | | { |
| | 0 | 89 | | if (reader.TokenType == JsonTokenType.Null) |
| | 0 | 90 | | { |
| | 0 | 91 | | return null; |
| | | 92 | | } |
| | | 93 | | |
| | 0 | 94 | | T value = _elementConverter.ReadNumberWithCustomHandling(ref reader, numberHandling, options); |
| | 0 | 95 | | return value; |
| | 0 | 96 | | } |
| | | 97 | | |
| | | 98 | | internal override void WriteNumberWithCustomHandling(Utf8JsonWriter writer, T? value, JsonNumberHandling handlin |
| | 0 | 99 | | { |
| | 0 | 100 | | if (value is null) |
| | 0 | 101 | | { |
| | 0 | 102 | | writer.WriteNullValue(); |
| | 0 | 103 | | } |
| | | 104 | | else |
| | 0 | 105 | | { |
| | 0 | 106 | | _elementConverter.WriteNumberWithCustomHandling(writer, value.Value, handling); |
| | 0 | 107 | | } |
| | 0 | 108 | | } |
| | | 109 | | |
| | | 110 | | internal override JsonValueType GetSupportedJsonValueTypes(JsonNumberHandling numberHandling) => |
| | 0 | 111 | | _elementConverter.GetSupportedJsonValueTypes(numberHandling); |
| | | 112 | | } |
| | | 113 | | } |
| | | 114 | | |