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JsonSerializerOptions.cs
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JsonSerializerOptions.cs
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Collections.Concurrent;
using System.ComponentModel;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.CompilerServices;
using System.Text.Encodings.Web;
using System.Text.Json.Nodes;
using System.Text.Json.Serialization;
using System.Text.Json.Serialization.Metadata;
namespace System.Text.Json
{
/// <summary>
/// Provides options to be used with <see cref="JsonSerializer"/>.
/// </summary>
public sealed partial class JsonSerializerOptions
{
internal const int BufferSizeDefault = 16 * 1024;
internal static readonly JsonSerializerOptions s_defaultOptions = new JsonSerializerOptions();
private readonly ConcurrentDictionary<Type, JsonTypeInfo> _classes = new ConcurrentDictionary<Type, JsonTypeInfo>();
// Simple LRU cache for the public (de)serialize entry points that avoid some lookups in _classes.
// Although this may be written by multiple threads, 'volatile' was not added since any local affinity is fine.
private JsonTypeInfo? _lastClass { get; set; }
internal JsonSerializerContext? _context;
private Func<Type, JsonSerializerOptions, JsonTypeInfo>? _typeInfoCreationFunc;
// For any new option added, adding it to the options copied in the copy constructor below must be considered.
private MemberAccessor? _memberAccessorStrategy;
private JsonNamingPolicy? _dictionaryKeyPolicy;
private JsonNamingPolicy? _jsonPropertyNamingPolicy;
private JsonCommentHandling _readCommentHandling;
private ReferenceHandler? _referenceHandler;
private JavaScriptEncoder? _encoder;
private JsonIgnoreCondition _defaultIgnoreCondition;
private JsonNumberHandling _numberHandling;
private JsonUnknownTypeHandling _unknownTypeHandling;
private int _defaultBufferSize = BufferSizeDefault;
private int _maxDepth;
private bool _allowTrailingCommas;
private bool _haveTypesBeenCreated;
private bool _ignoreNullValues;
private bool _ignoreReadOnlyProperties;
private bool _ignoreReadonlyFields;
private bool _includeFields;
private bool _propertyNameCaseInsensitive;
private bool _writeIndented;
/// <summary>
/// Constructs a new <see cref="JsonSerializerOptions"/> instance.
/// </summary>
public JsonSerializerOptions()
{
Converters = new ConverterList(this);
TrackOptionsInstance(this);
}
/// <summary>
/// Copies the options from a <see cref="JsonSerializerOptions"/> instance to a new instance.
/// </summary>
/// <param name="options">The <see cref="JsonSerializerOptions"/> instance to copy options from.</param>
/// <exception cref="System.ArgumentNullException">
/// <paramref name="options"/> is <see langword="null"/>.
/// </exception>
public JsonSerializerOptions(JsonSerializerOptions options)
{
if (options == null)
{
throw new ArgumentNullException(nameof(options));
}
_memberAccessorStrategy = options._memberAccessorStrategy;
_dictionaryKeyPolicy = options._dictionaryKeyPolicy;
_jsonPropertyNamingPolicy = options._jsonPropertyNamingPolicy;
_readCommentHandling = options._readCommentHandling;
_referenceHandler = options._referenceHandler;
_encoder = options._encoder;
_defaultIgnoreCondition = options._defaultIgnoreCondition;
_numberHandling = options._numberHandling;
_unknownTypeHandling = options._unknownTypeHandling;
_defaultBufferSize = options._defaultBufferSize;
_maxDepth = options._maxDepth;
_allowTrailingCommas = options._allowTrailingCommas;
_ignoreNullValues = options._ignoreNullValues;
_ignoreReadOnlyProperties = options._ignoreReadOnlyProperties;
_ignoreReadonlyFields = options._ignoreReadonlyFields;
_includeFields = options._includeFields;
_propertyNameCaseInsensitive = options._propertyNameCaseInsensitive;
_writeIndented = options._writeIndented;
Converters = new ConverterList(this, (ConverterList)options.Converters);
EffectiveMaxDepth = options.EffectiveMaxDepth;
ReferenceHandlingStrategy = options.ReferenceHandlingStrategy;
// _classes is not copied as sharing the JsonTypeInfo and JsonPropertyInfo caches can result in
// unnecessary references to type metadata, potentially hindering garbage collection on the source options.
// _haveTypesBeenCreated is not copied; it's okay to make changes to this options instance as (de)serialization has not occurred.
TrackOptionsInstance(this);
}
/// <summary>Tracks the options instance to enable all instances to be enumerated.</summary>
private static void TrackOptionsInstance(JsonSerializerOptions options) => TrackedOptionsInstances.All.Add(options, null);
internal static class TrackedOptionsInstances
{
/// <summary>Tracks all live JsonSerializerOptions instances.</summary>
/// <remarks>Instances are added to the table in their constructor.</remarks>
public static ConditionalWeakTable<JsonSerializerOptions, object?> All { get; } =
// TODO https://github.com/dotnet/runtime/issues/51159:
// Look into linking this away / disabling it when hot reload isn't in use.
new ConditionalWeakTable<JsonSerializerOptions, object?>();
}
/// <summary>
/// Constructs a new <see cref="JsonSerializerOptions"/> instance with a predefined set of options determined by the specified <see cref="JsonSerializerDefaults"/>.
/// </summary>
/// <param name="defaults"> The <see cref="JsonSerializerDefaults"/> to reason about.</param>
public JsonSerializerOptions(JsonSerializerDefaults defaults) : this()
{
if (defaults == JsonSerializerDefaults.Web)
{
_propertyNameCaseInsensitive = true;
_jsonPropertyNamingPolicy = JsonNamingPolicy.CamelCase;
_numberHandling = JsonNumberHandling.AllowReadingFromString;
}
else if (defaults != JsonSerializerDefaults.General)
{
throw new ArgumentOutOfRangeException(nameof(defaults));
}
}
/// <summary>
/// Binds current <see cref="JsonSerializerOptions"/> instance with a new instance of the specified <see cref="JsonSerializerContext"/> type.
/// </summary>
/// <typeparam name="TContext">The generic definition of the specified context type.</typeparam>
/// <remarks>When serializing and deserializing types using the options
/// instance, metadata for the types will be fetched from the context instance.
/// </remarks>
public void AddContext<TContext>() where TContext : JsonSerializerContext, new()
{
if (_context != null)
{
ThrowHelper.ThrowInvalidOperationException_JsonSerializerOptionsAlreadyBoundToContext();
}
TContext context = new();
_context = context;
context._options = this;
}
/// <summary>
/// Defines whether an extra comma at the end of a list of JSON values in an object or array
/// is allowed (and ignored) within the JSON payload being deserialized.
/// </summary>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// </exception>
/// <remarks>
/// By default, it's set to false, and <exception cref="JsonException"/> is thrown if a trailing comma is encountered.
/// </remarks>
public bool AllowTrailingCommas
{
get
{
return _allowTrailingCommas;
}
set
{
VerifyMutable();
_allowTrailingCommas = value;
}
}
/// <summary>
/// The default buffer size in bytes used when creating temporary buffers.
/// </summary>
/// <remarks>The default size is 16K.</remarks>
/// <exception cref="System.ArgumentException">Thrown when the buffer size is less than 1.</exception>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// </exception>
public int DefaultBufferSize
{
get
{
return _defaultBufferSize;
}
set
{
VerifyMutable();
if (value < 1)
{
throw new ArgumentException(SR.SerializationInvalidBufferSize);
}
_defaultBufferSize = value;
}
}
/// <summary>
/// The encoder to use when escaping strings, or <see langword="null" /> to use the default encoder.
/// </summary>
public JavaScriptEncoder? Encoder
{
get
{
return _encoder;
}
set
{
VerifyMutable();
_encoder = value;
}
}
/// <summary>
/// Specifies the policy used to convert a <see cref="System.Collections.IDictionary"/> key's name to another format, such as camel-casing.
/// </summary>
/// <remarks>
/// This property can be set to <see cref="JsonNamingPolicy.CamelCase"/> to specify a camel-casing policy.
/// It is not used when deserializing.
/// </remarks>
public JsonNamingPolicy? DictionaryKeyPolicy
{
get
{
return _dictionaryKeyPolicy;
}
set
{
VerifyMutable();
_dictionaryKeyPolicy = value;
}
}
/// <summary>
/// Determines whether null values are ignored during serialization and deserialization.
/// The default value is false.
/// </summary>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// or <see cref="DefaultIgnoreCondition"/> has been set to a non-default value. These properties cannot be used together.
/// </exception>
[Obsolete(Obsoletions.JsonSerializerOptionsIgnoreNullValuesMessage, DiagnosticId = Obsoletions.JsonSerializerOptionsIgnoreNullValuesDiagId, UrlFormat = Obsoletions.SharedUrlFormat)]
[EditorBrowsable(EditorBrowsableState.Never)]
public bool IgnoreNullValues
{
get
{
return _ignoreNullValues;
}
set
{
VerifyMutable();
if (value && _defaultIgnoreCondition != JsonIgnoreCondition.Never)
{
throw new InvalidOperationException(SR.DefaultIgnoreConditionAlreadySpecified);
}
_ignoreNullValues = value;
}
}
/// <summary>
/// Specifies a condition to determine when properties with default values are ignored during serialization or deserialization.
/// The default value is <see cref="JsonIgnoreCondition.Never" />.
/// </summary>
/// <exception cref="ArgumentException">
/// Thrown if this property is set to <see cref="JsonIgnoreCondition.Always"/>.
/// </exception>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred,
/// or <see cref="IgnoreNullValues"/> has been set to <see langword="true"/>. These properties cannot be used together.
/// </exception>
public JsonIgnoreCondition DefaultIgnoreCondition
{
get
{
return _defaultIgnoreCondition;
}
set
{
VerifyMutable();
if (value == JsonIgnoreCondition.Always)
{
throw new ArgumentException(SR.DefaultIgnoreConditionInvalid);
}
if (value != JsonIgnoreCondition.Never && _ignoreNullValues)
{
throw new InvalidOperationException(SR.DefaultIgnoreConditionAlreadySpecified);
}
_defaultIgnoreCondition = value;
}
}
/// <summary>
/// Specifies how number types should be handled when serializing or deserializing.
/// </summary>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// </exception>
public JsonNumberHandling NumberHandling
{
get => _numberHandling;
set
{
VerifyMutable();
if (!JsonSerializer.IsValidNumberHandlingValue(value))
{
throw new ArgumentOutOfRangeException(nameof(value));
}
_numberHandling = value;
}
}
/// <summary>
/// Determines whether read-only properties are ignored during serialization.
/// A property is read-only if it contains a public getter but not a public setter.
/// The default value is false.
/// </summary>
/// <remarks>
/// Read-only properties are not deserialized regardless of this setting.
/// </remarks>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// </exception>
public bool IgnoreReadOnlyProperties
{
get
{
return _ignoreReadOnlyProperties;
}
set
{
VerifyMutable();
_ignoreReadOnlyProperties = value;
}
}
/// <summary>
/// Determines whether read-only fields are ignored during serialization.
/// A field is read-only if it is marked with the <c>readonly</c> keyword.
/// The default value is false.
/// </summary>
/// <remarks>
/// Read-only fields are not deserialized regardless of this setting.
/// </remarks>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// </exception>
public bool IgnoreReadOnlyFields
{
get
{
return _ignoreReadonlyFields;
}
set
{
VerifyMutable();
_ignoreReadonlyFields = value;
}
}
/// <summary>
/// Determines whether fields are handled on serialization and deserialization.
/// The default value is false.
/// </summary>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// </exception>
public bool IncludeFields
{
get
{
return _includeFields;
}
set
{
VerifyMutable();
_includeFields = value;
}
}
/// <summary>
/// Gets or sets the maximum depth allowed when serializing or deserializing JSON, with the default (i.e. 0) indicating a max depth of 64.
/// </summary>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// Thrown when the max depth is set to a negative value.
/// </exception>
/// <remarks>
/// Going past this depth will throw a <exception cref="JsonException"/>.
/// </remarks>
public int MaxDepth
{
get => _maxDepth;
set
{
VerifyMutable();
if (value < 0)
{
throw ThrowHelper.GetArgumentOutOfRangeException_MaxDepthMustBePositive(nameof(value));
}
_maxDepth = value;
EffectiveMaxDepth = (value == 0 ? JsonReaderOptions.DefaultMaxDepth : value);
}
}
// The default is 64 because that is what the reader uses, so re-use the same JsonReaderOptions.DefaultMaxDepth constant.
internal int EffectiveMaxDepth { get; private set; } = JsonReaderOptions.DefaultMaxDepth;
/// <summary>
/// Specifies the policy used to convert a property's name on an object to another format, such as camel-casing.
/// The resulting property name is expected to match the JSON payload during deserialization, and
/// will be used when writing the property name during serialization.
/// </summary>
/// <remarks>
/// The policy is not used for properties that have a <see cref="JsonPropertyNameAttribute"/> applied.
/// This property can be set to <see cref="JsonNamingPolicy.CamelCase"/> to specify a camel-casing policy.
/// </remarks>
public JsonNamingPolicy? PropertyNamingPolicy
{
get
{
return _jsonPropertyNamingPolicy;
}
set
{
VerifyMutable();
_jsonPropertyNamingPolicy = value;
}
}
/// <summary>
/// Determines whether a property's name uses a case-insensitive comparison during deserialization.
/// The default value is false.
/// </summary>
/// <remarks>There is a performance cost associated when the value is true.</remarks>
public bool PropertyNameCaseInsensitive
{
get
{
return _propertyNameCaseInsensitive;
}
set
{
VerifyMutable();
_propertyNameCaseInsensitive = value;
}
}
/// <summary>
/// Defines how the comments are handled during deserialization.
/// </summary>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// Thrown when the comment handling enum is set to a value that is not supported (or not within the <see cref="JsonCommentHandling"/> enum range).
/// </exception>
/// <remarks>
/// By default <exception cref="JsonException"/> is thrown if a comment is encountered.
/// </remarks>
public JsonCommentHandling ReadCommentHandling
{
get
{
return _readCommentHandling;
}
set
{
VerifyMutable();
Debug.Assert(value >= 0);
if (value > JsonCommentHandling.Skip)
throw new ArgumentOutOfRangeException(nameof(value), SR.JsonSerializerDoesNotSupportComments);
_readCommentHandling = value;
}
}
/// <summary>
/// Defines how deserializing a type declared as an <see cref="object"/> is handled during deserialization.
/// </summary>
public JsonUnknownTypeHandling UnknownTypeHandling
{
get => _unknownTypeHandling;
set
{
VerifyMutable();
_unknownTypeHandling = value;
}
}
/// <summary>
/// Defines whether JSON should pretty print which includes:
/// indenting nested JSON tokens, adding new lines, and adding white space between property names and values.
/// By default, the JSON is serialized without any extra white space.
/// </summary>
/// <exception cref="InvalidOperationException">
/// Thrown if this property is set after serialization or deserialization has occurred.
/// </exception>
public bool WriteIndented
{
get
{
return _writeIndented;
}
set
{
VerifyMutable();
_writeIndented = value;
}
}
/// <summary>
/// Configures how object references are handled when reading and writing JSON.
/// </summary>
public ReferenceHandler? ReferenceHandler
{
get => _referenceHandler;
set
{
VerifyMutable();
_referenceHandler = value;
ReferenceHandlingStrategy = value?.HandlingStrategy ?? ReferenceHandlingStrategy.None;
}
}
// The cached value used to determine if ReferenceHandler should use Preserve or IgnoreCycles semanitcs or None of them.
internal ReferenceHandlingStrategy ReferenceHandlingStrategy = ReferenceHandlingStrategy.None;
internal MemberAccessor MemberAccessorStrategy
{
get
{
if (_memberAccessorStrategy == null)
{
#if NETCOREAPP
// if dynamic code isn't supported, fallback to reflection
_memberAccessorStrategy = RuntimeFeature.IsDynamicCodeSupported ?
new ReflectionEmitMemberAccessor() :
new ReflectionMemberAccessor();
#elif NETFRAMEWORK
_memberAccessorStrategy = new ReflectionEmitMemberAccessor();
#else
_memberAccessorStrategy = new ReflectionMemberAccessor();
#endif
}
return _memberAccessorStrategy;
}
}
/// <summary>
/// Whether <see cref="InitializeForReflectionSerializer()"/> needs to be called.
/// </summary>
internal bool IsInitializedForReflectionSerializer { get; set; }
/// <summary>
/// Initializes the converters for the reflection-based serializer.
/// <seealso cref="InitializeForReflectionSerializer"/> must be checked before calling.
/// </summary>
[RequiresUnreferencedCode(JsonSerializer.SerializationUnreferencedCodeMessage)]
internal void InitializeForReflectionSerializer()
{
// For threading cases, the state that is set here can be overwritten.
RootBuiltInConverters();
_typeInfoCreationFunc = CreateJsonTypeInfo;
IsInitializedForReflectionSerializer = true;
[RequiresUnreferencedCode(JsonSerializer.SerializationUnreferencedCodeMessage)]
static JsonTypeInfo CreateJsonTypeInfo(Type type, JsonSerializerOptions options) => new JsonTypeInfo(type, options);
}
internal JsonTypeInfo GetOrAddClass(Type type)
{
_haveTypesBeenCreated = true;
if (!TryGetClass(type, out JsonTypeInfo? result))
{
result = _classes.GetOrAdd(type, GetClassFromContextOrCreate(type));
}
return result;
}
internal JsonTypeInfo GetClassFromContextOrCreate(Type type)
{
JsonTypeInfo? info = _context?.GetTypeInfo(type);
if (info != null)
{
return info;
}
if (_typeInfoCreationFunc == null)
{
ThrowHelper.ThrowNotSupportedException_NoMetadataForType(type);
return null!;
}
return _typeInfoCreationFunc(type, this);
}
/// <summary>
/// Return the TypeInfo for root API calls.
/// This has a LRU cache that is intended only for public API calls that specify the root type.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal JsonTypeInfo GetOrAddClassForRootType(Type type)
{
JsonTypeInfo? jsonTypeInfo = _lastClass;
if (jsonTypeInfo?.Type != type)
{
jsonTypeInfo = GetOrAddClass(type);
_lastClass = jsonTypeInfo;
}
return jsonTypeInfo;
}
internal bool TryGetClass(Type type, [NotNullWhen(true)] out JsonTypeInfo? jsonTypeInfo)
{
// todo: for performance and reduced instances, consider using the converters and JsonTypeInfo from s_defaultOptions by cloning (or reference directly if no changes).
// https://github.com/dotnet/runtime/issues/32357
if (!_classes.TryGetValue(type, out JsonTypeInfo? result))
{
jsonTypeInfo = null;
return false;
}
jsonTypeInfo = result;
return true;
}
internal bool TypeIsCached(Type type)
{
return _classes.ContainsKey(type);
}
internal void ClearClasses()
{
_classes.Clear();
_lastClass = null;
}
internal JsonDocumentOptions GetDocumentOptions()
{
return new JsonDocumentOptions
{
AllowTrailingCommas = AllowTrailingCommas,
CommentHandling = ReadCommentHandling,
MaxDepth = MaxDepth
};
}
internal JsonNodeOptions GetNodeOptions()
{
return new JsonNodeOptions
{
PropertyNameCaseInsensitive = PropertyNameCaseInsensitive
};
}
internal JsonReaderOptions GetReaderOptions()
{
return new JsonReaderOptions
{
AllowTrailingCommas = AllowTrailingCommas,
CommentHandling = ReadCommentHandling,
MaxDepth = MaxDepth
};
}
internal JsonWriterOptions GetWriterOptions()
{
return new JsonWriterOptions
{
Encoder = Encoder,
Indented = WriteIndented,
#if !DEBUG
SkipValidation = true
#endif
};
}
internal void VerifyMutable()
{
// The default options are hidden and thus should be immutable.
Debug.Assert(this != s_defaultOptions);
if (_haveTypesBeenCreated || _context != null)
{
ThrowHelper.ThrowInvalidOperationException_SerializerOptionsImmutable(_context);
}
}
}
}