internal static ReadOnlySpan <byte> GetPropertyName(
            ref ReadStack state,
            ref Utf8JsonReader reader,
            JsonSerializerOptions options)
        {
            ReadOnlySpan <byte> unescapedPropertyName;
            ReadOnlySpan <byte> propertyName = reader.GetSpan();

            if (reader.ValueIsEscaped)
            {
                unescapedPropertyName = JsonReaderHelper.GetUnescapedSpan(propertyName);
            }
            else
            {
                unescapedPropertyName = propertyName;
            }

            if (state.Current.CanContainMetadata)
            {
                if (IsMetadataPropertyName(propertyName, state.Current.BaseJsonTypeInfo.PolymorphicTypeResolver))
                {
                    ThrowHelper.ThrowUnexpectedMetadataException(propertyName, ref reader, ref state);
                }
            }

            return(unescapedPropertyName);
        }
        internal static ReadOnlySpan <byte> GetPropertyName(
            ref ReadStack state,
            ref Utf8JsonReader reader,
            JsonSerializerOptions options)
        {
            ReadOnlySpan <byte> unescapedPropertyName;
            ReadOnlySpan <byte> propertyName = reader.GetSpan();

            if (reader._stringHasEscaping)
            {
                int idx = propertyName.IndexOf(JsonConstants.BackSlash);
                Debug.Assert(idx != -1);
                unescapedPropertyName = JsonReaderHelper.GetUnescapedSpan(propertyName, idx);
            }
            else
            {
                unescapedPropertyName = propertyName;
            }

            if (state.CanContainMetadata)
            {
                if (propertyName.Length > 0 && propertyName[0] == '$')
                {
                    ThrowHelper.ThrowUnexpectedMetadataException(propertyName, ref reader, ref state);
                }
            }

            return(unescapedPropertyName);
        }
        internal static bool TryReadMetadata(JsonConverter converter, ref Utf8JsonReader reader, ref ReadStack state)
        {
            Debug.Assert(state.Current.ObjectState == StackFrameObjectState.StartToken);
            Debug.Assert(state.CanContainMetadata);

            while (true)
            {
                if (state.Current.PropertyState == StackFramePropertyState.None)
                {
                    state.Current.PropertyState = StackFramePropertyState.ReadName;

                    // Read the property name.
                    if (!reader.Read())
                    {
                        return(false);
                    }
                }

                if (state.Current.PropertyState < StackFramePropertyState.Name)
                {
                    if (reader.TokenType == JsonTokenType.EndObject)
                    {
                        // Read the entire object while parsing for metadata.
                        return(true);
                    }

                    // We just read a property. The only valid next tokens are EndObject and PropertyName.
                    Debug.Assert(reader.TokenType == JsonTokenType.PropertyName);

                    if (state.Current.MetadataPropertyNames.HasFlag(MetadataPropertyName.Ref))
                    {
                        // No properties whatsoever should follow a $ref property.
                        ThrowHelper.ThrowJsonException_MetadataReferenceObjectCannotContainOtherProperties(reader.GetSpan(), ref state);
                    }

                    ReadOnlySpan <byte> propertyName = reader.GetSpan();
                    switch (state.Current.LatestMetadataPropertyName = GetMetadataPropertyName(propertyName))
                    {
                    case MetadataPropertyName.Id:
                        state.Current.JsonPropertyName = s_idPropertyName;

                        if ((state.Current.MetadataPropertyNames & (MetadataPropertyName.Id | MetadataPropertyName.Ref)) != 0)
                        {
                            // No $id or $ref properties should precede $id properties.
                            ThrowHelper.ThrowJsonException_MetadataIdIsNotFirstProperty(propertyName, ref state);
                        }
                        if (!converter.CanHaveMetadata)
                        {
                            // Should not be permitted unless the converter is capable of handling metadata.
                            ThrowHelper.ThrowJsonException_MetadataCannotParsePreservedObjectIntoImmutable(converter.TypeToConvert);
                        }

                        break;

                    case MetadataPropertyName.Ref:
                        state.Current.JsonPropertyName = s_refPropertyName;

                        if (converter.IsValueType)
                        {
                            // Should not be permitted if the converter is a struct.
                            ThrowHelper.ThrowJsonException_MetadataInvalidReferenceToValueType(converter.TypeToConvert);
                        }
                        if (state.Current.MetadataPropertyNames != 0)
                        {
                            // No metadata properties should precede a $ref property.
                            ThrowHelper.ThrowJsonException_MetadataReferenceObjectCannotContainOtherProperties(reader.GetSpan(), ref state);
                        }

                        break;

                    case MetadataPropertyName.Values:
                        state.Current.JsonPropertyName = s_valuesPropertyName;

                        if (state.Current.MetadataPropertyNames == MetadataPropertyName.None)
                        {
                            // Cannot have a $values property unless there are preceding metadata properties.
                            ThrowHelper.ThrowJsonException_MetadataMissingIdBeforeValues(ref state, propertyName);
                        }

                        break;

                    default:
                        Debug.Assert(state.Current.LatestMetadataPropertyName == MetadataPropertyName.None);

                        // Encountered a non-metadata property, exit the reader.
                        return(true);
                    }

                    state.Current.PropertyState = StackFramePropertyState.Name;
                }

                if (state.Current.PropertyState < StackFramePropertyState.ReadValue)
                {
                    state.Current.PropertyState = StackFramePropertyState.ReadValue;

                    // Read the property value.
                    if (!reader.Read())
                    {
                        return(false);
                    }
                }

                Debug.Assert(state.Current.PropertyState == StackFramePropertyState.ReadValue);

                switch (state.Current.LatestMetadataPropertyName)
                {
                case MetadataPropertyName.Id:
                    if (reader.TokenType != JsonTokenType.String)
                    {
                        ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
                    }

                    if (state.ReferenceId != null)
                    {
                        ThrowHelper.ThrowNotSupportedException_ObjectWithParameterizedCtorRefMetadataNotSupported(s_refPropertyName, ref reader, ref state);
                    }

                    state.ReferenceId = reader.GetString();
                    break;

                case MetadataPropertyName.Ref:
                    if (reader.TokenType != JsonTokenType.String)
                    {
                        ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
                    }

                    if (state.ReferenceId != null)
                    {
                        ThrowHelper.ThrowNotSupportedException_ObjectWithParameterizedCtorRefMetadataNotSupported(s_refPropertyName, ref reader, ref state);
                    }

                    state.ReferenceId = reader.GetString();
                    break;

                case MetadataPropertyName.Values:

                    if (reader.TokenType != JsonTokenType.StartArray)
                    {
                        ThrowHelper.ThrowJsonException_MetadataValuesInvalidToken(reader.TokenType);
                    }

                    state.Current.PropertyState          = StackFramePropertyState.None;
                    state.Current.MetadataPropertyNames |= state.Current.LatestMetadataPropertyName;
                    return(true);    // "$values" property contains the nested payload, exit the metadata reader now.

                default:
                    Debug.Fail("Non-metadata properties should not reach this stage.");
                    break;
                }

                state.Current.MetadataPropertyNames |= state.Current.LatestMetadataPropertyName;
                state.Current.PropertyState          = StackFramePropertyState.None;
                state.Current.JsonPropertyName       = null;
            }
        }
Exemple #4
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        /// <summary>
        /// Returns true if successful, false is the reader ran out of buffer.
        /// Sets state.Current.ReturnValue to the $ref target for MetadataRefProperty cases.
        /// </summary>
        internal static bool ResolveMetadata(
            JsonConverter converter,
            ref Utf8JsonReader reader,
            ref ReadStack state)
        {
            if (state.Current.ObjectState < StackFrameObjectState.ReadAheadNameOrEndObject)
            {
                // Read the first metadata property name.
                if (!ReadAheadMetataDataAndSetState(ref reader, ref state, StackFrameObjectState.ReadNameOrEndObject))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadNameOrEndObject)
            {
                if (reader.TokenType != JsonTokenType.PropertyName)
                {
                    // An enumerable needs metadata since it starts with StartObject.
                    if (converter.ClassType == ClassType.Enumerable)
                    {
                        ThrowHelper.ThrowJsonException_MetadataPreservedArrayValuesNotFound(converter.TypeToConvert);
                    }

                    // The reader should have detected other invalid cases.
                    Debug.Assert(reader.TokenType == JsonTokenType.EndObject);

                    // Skip the read of the first property name, since we already read it above.
                    state.Current.PropertyState = StackFramePropertyState.ReadName;

                    return(true);
                }

                ReadOnlySpan <byte>  propertyName = reader.GetSpan();
                MetadataPropertyName metadata     = GetMetadataPropertyName(propertyName);
                if (metadata == MetadataPropertyName.Id)
                {
                    state.Current.JsonPropertyName = propertyName.ToArray();
                    if (!converter.CanHaveIdMetadata)
                    {
                        ThrowHelper.ThrowJsonException_MetadataCannotParsePreservedObjectIntoImmutable(converter.TypeToConvert);
                    }

                    state.Current.ObjectState = StackFrameObjectState.ReadAheadIdValue;
                }
                else if (metadata == MetadataPropertyName.Ref)
                {
                    state.Current.JsonPropertyName = propertyName.ToArray();
                    if (converter.IsValueType)
                    {
                        ThrowHelper.ThrowJsonException_MetadataInvalidReferenceToValueType(converter.TypeToConvert);
                    }

                    state.Current.ObjectState = StackFrameObjectState.ReadAheadRefValue;
                }
                else if (metadata == MetadataPropertyName.Values)
                {
                    state.Current.JsonPropertyName = propertyName.ToArray();
                    if (converter.ClassType == ClassType.Enumerable)
                    {
                        ThrowHelper.ThrowJsonException_MetadataMissingIdBeforeValues();
                    }
                    else
                    {
                        ThrowHelper.ThrowJsonException_MetadataInvalidPropertyWithLeadingDollarSign(propertyName, ref state, reader);
                    }
                }
                else
                {
                    Debug.Assert(metadata == MetadataPropertyName.NoMetadata);

                    // Having a StartObject without metadata properties is not allowed.
                    if (converter.ClassType == ClassType.Enumerable)
                    {
                        state.Current.JsonPropertyName = propertyName.ToArray();
                        ThrowHelper.ThrowJsonException_MetadataPreservedArrayInvalidProperty(converter.TypeToConvert, reader);
                    }

                    // Skip the read of the first property name, since we already read it above.
                    state.Current.PropertyState = StackFramePropertyState.ReadName;
                    return(true);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadRefValue)
            {
                if (!ReadAheadMetataDataAndSetState(ref reader, ref state, StackFrameObjectState.ReadRefValue))
                {
                    return(false);
                }
            }
            else if (state.Current.ObjectState == StackFrameObjectState.ReadAheadIdValue)
            {
                if (!ReadAheadMetataDataAndSetState(ref reader, ref state, StackFrameObjectState.ReadIdValue))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadRefValue)
            {
                if (reader.TokenType != JsonTokenType.String)
                {
                    ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
                }

                string key = reader.GetString() !;

                // todo: https://github.com/dotnet/runtime/issues/32354
                state.Current.ReturnValue = state.ReferenceResolver.ResolveReferenceOnDeserialize(key);
                state.Current.ObjectState = StackFrameObjectState.ReadAheadRefEndObject;
            }
            else if (state.Current.ObjectState == StackFrameObjectState.ReadIdValue)
            {
                if (reader.TokenType != JsonTokenType.String)
                {
                    ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
                }

                state.Current.MetadataId = reader.GetString();

                // Clear the MetadataPropertyName since we are done processing Id.
                state.Current.JsonPropertyName = default;

                if (converter.ClassType == ClassType.Enumerable)
                {
                    // Need to Read $values property name.
                    state.Current.ObjectState = StackFrameObjectState.ReadAheadValuesName;
                }
                else
                {
                    // We are done reading metadata.
                    state.Current.ObjectState = StackFrameObjectState.PropertyValue;
                    return(true);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadRefEndObject)
            {
                if (!ReadAheadMetataDataAndSetState(ref reader, ref state, StackFrameObjectState.ReadRefEndObject))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadRefEndObject)
            {
                if (reader.TokenType != JsonTokenType.EndObject)
                {
                    // We just read a property. The only valid next tokens are EndObject and PropertyName.
                    Debug.Assert(reader.TokenType == JsonTokenType.PropertyName);

                    ThrowHelper.ThrowJsonException_MetadataReferenceObjectCannotContainOtherProperties(reader.GetSpan(), ref state);
                }

                return(true);
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadValuesName)
            {
                if (!ReadAheadMetataDataAndSetState(ref reader, ref state, StackFrameObjectState.ReadValuesName))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadValuesName)
            {
                if (reader.TokenType != JsonTokenType.PropertyName)
                {
                    ThrowHelper.ThrowJsonException_MetadataPreservedArrayValuesNotFound(converter.TypeToConvert);
                }

                ReadOnlySpan <byte> propertyName = reader.GetSpan();

                // Remember the property in case we get an exception.
                state.Current.JsonPropertyName = propertyName.ToArray();

                if (GetMetadataPropertyName(propertyName) != MetadataPropertyName.Values)
                {
                    ThrowHelper.ThrowJsonException_MetadataPreservedArrayInvalidProperty(converter.TypeToConvert, reader);
                }

                state.Current.ObjectState = StackFrameObjectState.ReadAheadValuesStartArray;
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadValuesStartArray)
            {
                if (!ReadAheadMetataDataAndSetState(ref reader, ref state, StackFrameObjectState.ReadValuesStartArray))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadValuesStartArray)
            {
                if (reader.TokenType != JsonTokenType.StartArray)
                {
                    ThrowHelper.ThrowJsonException_MetadataValuesInvalidToken(reader.TokenType);
                }

                state.Current.ObjectState = StackFrameObjectState.PropertyValue;
            }

            return(true);
        }
Exemple #5
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        internal static JsonPropertyInfo LookupProperty(
            object obj,
            ref Utf8JsonReader reader,
            JsonSerializerOptions options,
            ref ReadStack state,
            out bool useExtensionProperty)
        {
            Debug.Assert(state.Current.JsonClassInfo.ClassType == ClassType.Object);

            JsonPropertyInfo jsonPropertyInfo;

            ReadOnlySpan <byte> unescapedPropertyName;
            ReadOnlySpan <byte> propertyName = reader.GetSpan();

            if (reader._stringHasEscaping)
            {
                int idx = propertyName.IndexOf(JsonConstants.BackSlash);
                Debug.Assert(idx != -1);
                unescapedPropertyName = GetUnescapedString(propertyName, idx);
            }
            else
            {
                unescapedPropertyName = propertyName;
            }

            if (options.ReferenceHandling.ShouldReadPreservedReferences())
            {
                if (propertyName.Length > 0 && propertyName[0] == '$')
                {
                    ThrowHelper.ThrowUnexpectedMetadataException(propertyName, ref reader, ref state);
                }
            }

            jsonPropertyInfo = state.Current.JsonClassInfo.GetProperty(unescapedPropertyName, ref state.Current);

            // Increment PropertyIndex so GetProperty() starts with the next property the next time this function is called.
            state.Current.PropertyIndex++;

            // Determine if we should use the extension property.
            if (jsonPropertyInfo == JsonPropertyInfo.s_missingProperty)
            {
                JsonPropertyInfo?dataExtProperty = state.Current.JsonClassInfo.DataExtensionProperty;
                if (dataExtProperty != null)
                {
                    state.Current.JsonPropertyNameAsString = JsonHelpers.Utf8GetString(unescapedPropertyName);
                    CreateDataExtensionProperty(obj, dataExtProperty);
                    jsonPropertyInfo = dataExtProperty;
                }

                state.Current.JsonPropertyInfo = jsonPropertyInfo;
                useExtensionProperty           = true;
                return(jsonPropertyInfo);
            }

            // Support JsonException.Path.
            Debug.Assert(
                jsonPropertyInfo.JsonPropertyName == null ||
                options.PropertyNameCaseInsensitive ||
                unescapedPropertyName.SequenceEqual(jsonPropertyInfo.JsonPropertyName));

            state.Current.JsonPropertyInfo = jsonPropertyInfo;

            if (jsonPropertyInfo.JsonPropertyName == null)
            {
                byte[] propertyNameArray = unescapedPropertyName.ToArray();
                if (options.PropertyNameCaseInsensitive)
                {
                    // Each payload can have a different name here; remember the value on the temporary stack.
                    state.Current.JsonPropertyName = propertyNameArray;
                }
                else
                {
                    // Prevent future allocs by caching globally on the JsonPropertyInfo which is specific to a Type+PropertyName
                    // so it will match the incoming payload except when case insensitivity is enabled (which is handled above).
                    state.Current.JsonPropertyInfo.JsonPropertyName = propertyNameArray;
                }
            }

            state.Current.JsonPropertyInfo = jsonPropertyInfo;
            useExtensionProperty           = false;
            return(jsonPropertyInfo);
        }
Exemple #6
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        /// <summary>
        /// Returns true if successful, false is the reader ran out of buffer.
        /// Sets state.Current.ReturnValue to the reference target for $ref cases;
        /// Sets state.Current.ReturnValue to a new instance for $id cases.
        /// </summary>
        internal static bool ResolveMetadataForJsonObject <T>(
            ref Utf8JsonReader reader,
            ref ReadStack state,
            JsonSerializerOptions options)
        {
            JsonConverter converter = state.Current.JsonTypeInfo.PropertyInfoForTypeInfo.ConverterBase;

            if (state.Current.ObjectState < StackFrameObjectState.ReadAheadNameOrEndObject)
            {
                // Read the first metadata property name.
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadNameOrEndObject))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadNameOrEndObject)
            {
                if (reader.TokenType != JsonTokenType.PropertyName)
                {
                    // Since this was an empty object, we are done reading metadata.
                    state.Current.ObjectState = StackFrameObjectState.PropertyValue;
                    // Skip the read of the first property name, since we already read it above.
                    state.Current.PropertyState = StackFramePropertyState.ReadName;
                    return(true);
                }

                ReadOnlySpan <byte>  propertyName = reader.GetSpan();
                MetadataPropertyName metadata     = GetMetadataPropertyName(propertyName);
                if (metadata == MetadataPropertyName.Id)
                {
                    state.Current.JsonPropertyName = s_idPropertyName;

                    if (!converter.CanHaveIdMetadata)
                    {
                        ThrowHelper.ThrowJsonException_MetadataCannotParsePreservedObjectIntoImmutable(converter.TypeToConvert);
                    }

                    state.Current.ObjectState = StackFrameObjectState.ReadAheadIdValue;
                }
                else if (metadata == MetadataPropertyName.Ref)
                {
                    state.Current.JsonPropertyName = s_refPropertyName;

                    if (converter.IsValueType)
                    {
                        ThrowHelper.ThrowJsonException_MetadataInvalidReferenceToValueType(converter.TypeToConvert);
                    }

                    state.Current.ObjectState = StackFrameObjectState.ReadAheadRefValue;
                }
                else if (metadata == MetadataPropertyName.Values)
                {
                    ThrowHelper.ThrowJsonException_MetadataInvalidPropertyWithLeadingDollarSign(propertyName, ref state, reader);
                }
                else
                {
                    Debug.Assert(metadata == MetadataPropertyName.NoMetadata);
                    // We are done reading metadata, the object didn't contain any.
                    state.Current.ObjectState = StackFrameObjectState.PropertyValue;
                    // Skip the read of the first property name, since we already read it above.
                    state.Current.PropertyState = StackFramePropertyState.ReadName;
                    return(true);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadRefValue)
            {
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadRefValue))
                {
                    return(false);
                }
            }
            else if (state.Current.ObjectState == StackFrameObjectState.ReadAheadIdValue)
            {
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadIdValue))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadRefValue)
            {
                if (reader.TokenType != JsonTokenType.String)
                {
                    ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
                }

                string referenceId = reader.GetString() !;
                object value       = state.ReferenceResolver.ResolveReference(referenceId);
                ValidateValueIsCorrectType <T>(value, referenceId);
                state.Current.ReturnValue = value;

                state.Current.ObjectState = StackFrameObjectState.ReadAheadRefEndObject;
            }
            else if (state.Current.ObjectState == StackFrameObjectState.ReadIdValue)
            {
                if (reader.TokenType != JsonTokenType.String)
                {
                    ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
                }

                converter.CreateInstanceForReferenceResolver(ref reader, ref state, options);

                string referenceId = reader.GetString() !;
                state.ReferenceResolver.AddReference(referenceId, state.Current.ReturnValue !);

                // We are done reading metadata plus we instantiated the object.
                state.Current.ObjectState = StackFrameObjectState.CreatedObject;
            }

            // Clear the metadata property name that was set in case of failure on ResolveReference/AddReference.
            state.Current.JsonPropertyName = null;

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadRefEndObject)
            {
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadRefEndObject))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadRefEndObject)
            {
                if (reader.TokenType != JsonTokenType.EndObject)
                {
                    // We just read a property. The only valid next tokens are EndObject and PropertyName.
                    Debug.Assert(reader.TokenType == JsonTokenType.PropertyName);

                    ThrowHelper.ThrowJsonException_MetadataReferenceObjectCannotContainOtherProperties(reader.GetSpan(), ref state);
                }
            }

            return(true);
        }
Exemple #7
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        /// <summary>
        /// Returns true if successful, false is the reader ran out of buffer.
        /// Sets state.Current.ReturnValue to the reference target for $ref cases;
        /// Sets state.Current.ReturnValue to a new instance for $id cases.
        /// </summary>
        internal static bool ResolveMetadataForJsonArray <T>(
            ref Utf8JsonReader reader,
            ref ReadStack state,
            JsonSerializerOptions options)
        {
            JsonConverter converter = state.Current.JsonTypeInfo.PropertyInfoForTypeInfo.ConverterBase;

            if (state.Current.ObjectState < StackFrameObjectState.ReadAheadNameOrEndObject)
            {
                // Read the first metadata property name.
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadNameOrEndObject))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadNameOrEndObject)
            {
                if (reader.TokenType != JsonTokenType.PropertyName)
                {
                    // The reader should have detected other invalid cases.
                    Debug.Assert(reader.TokenType == JsonTokenType.EndObject);

                    // An enumerable needs metadata since it starts with StartObject.
                    ThrowHelper.ThrowJsonException_MetadataPreservedArrayValuesNotFound(ref state, converter.TypeToConvert);
                }

                ReadOnlySpan <byte>  propertyName = reader.GetSpan();
                MetadataPropertyName metadata     = GetMetadataPropertyName(propertyName);
                if (metadata == MetadataPropertyName.Id)
                {
                    state.Current.JsonPropertyName = s_idPropertyName;

                    if (!converter.CanHaveIdMetadata)
                    {
                        ThrowHelper.ThrowJsonException_MetadataCannotParsePreservedObjectIntoImmutable(converter.TypeToConvert);
                    }

                    state.Current.ObjectState = StackFrameObjectState.ReadAheadIdValue;
                }
                else if (metadata == MetadataPropertyName.Ref)
                {
                    state.Current.JsonPropertyName = s_refPropertyName;

                    if (converter.IsValueType)
                    {
                        ThrowHelper.ThrowJsonException_MetadataInvalidReferenceToValueType(converter.TypeToConvert);
                    }

                    state.Current.ObjectState = StackFrameObjectState.ReadAheadRefValue;
                }
                else if (metadata == MetadataPropertyName.Values)
                {
                    ThrowHelper.ThrowJsonException_MetadataMissingIdBeforeValues(ref state, propertyName);
                }
                else
                {
                    Debug.Assert(metadata == MetadataPropertyName.NoMetadata);

                    // Having a StartObject without metadata properties is not allowed.
                    ThrowHelper.ThrowJsonException_MetadataPreservedArrayInvalidProperty(ref state, converter.TypeToConvert, reader);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadRefValue)
            {
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadRefValue))
                {
                    return(false);
                }
            }
            else if (state.Current.ObjectState == StackFrameObjectState.ReadAheadIdValue)
            {
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadIdValue))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadRefValue)
            {
                if (reader.TokenType != JsonTokenType.String)
                {
                    ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
                }

                string referenceId = reader.GetString() !;
                object value       = state.ReferenceResolver.ResolveReference(referenceId);
                ValidateValueIsCorrectType <T>(value, referenceId);
                state.Current.ReturnValue = value;

                state.Current.ObjectState = StackFrameObjectState.ReadAheadRefEndObject;
            }
            else if (state.Current.ObjectState == StackFrameObjectState.ReadIdValue)
            {
                if (reader.TokenType != JsonTokenType.String)
                {
                    ThrowHelper.ThrowJsonException_MetadataValueWasNotString(reader.TokenType);
                }

                converter.CreateInstanceForReferenceResolver(ref reader, ref state, options);

                string referenceId = reader.GetString() !;
                state.ReferenceResolver.AddReference(referenceId, state.Current.ReturnValue !);

                // Need to Read $values property name.
                state.Current.ObjectState = StackFrameObjectState.ReadAheadValuesName;
            }

            // Clear the metadata property name that was set in case of failure on ResolverReference/AddReference.
            state.Current.JsonPropertyName = null;

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadRefEndObject)
            {
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadRefEndObject))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadRefEndObject)
            {
                if (reader.TokenType != JsonTokenType.EndObject)
                {
                    // We just read a property. The only valid next tokens are EndObject and PropertyName.
                    Debug.Assert(reader.TokenType == JsonTokenType.PropertyName);

                    ThrowHelper.ThrowJsonException_MetadataReferenceObjectCannotContainOtherProperties(reader.GetSpan(), ref state);
                }

                return(true);
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadValuesName)
            {
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadValuesName))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadValuesName)
            {
                if (reader.TokenType != JsonTokenType.PropertyName)
                {
                    ThrowHelper.ThrowJsonException_MetadataPreservedArrayValuesNotFound(ref state, converter.TypeToConvert);
                }

                ReadOnlySpan <byte> propertyName = reader.GetSpan();

                if (GetMetadataPropertyName(propertyName) != MetadataPropertyName.Values)
                {
                    ThrowHelper.ThrowJsonException_MetadataPreservedArrayInvalidProperty(ref state, converter.TypeToConvert, reader);
                }

                // Remember the property in case we get an exception in one of the array elements.
                state.Current.JsonPropertyName = s_valuesPropertyName;

                state.Current.ObjectState = StackFrameObjectState.ReadAheadValuesStartArray;
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadAheadValuesStartArray)
            {
                if (!TryReadAheadMetadataAndSetState(ref reader, ref state, StackFrameObjectState.ReadValuesStartArray))
                {
                    return(false);
                }
            }

            if (state.Current.ObjectState == StackFrameObjectState.ReadValuesStartArray)
            {
                if (reader.TokenType != JsonTokenType.StartArray)
                {
                    ThrowHelper.ThrowJsonException_MetadataValuesInvalidToken(reader.TokenType);
                }
                state.Current.ValidateEndTokenOnArray = true;
                state.Current.ObjectState             = StackFrameObjectState.CreatedObject;
            }

            return(true);
        }