C# Serialization.JsonProperty类代码示例

    private void SerializePrimitive(JsonWriter writer, object value, JsonPrimitiveContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
    {
      if (contract.UnderlyingType == typeof (byte[]))
      {
        bool includeTypeDetails = ShouldWriteType(TypeNameHandling.Objects, contract, member, containerContract, containerProperty);
        if (includeTypeDetails)
        {
          writer.WriteStartObject();
          WriteTypeProperty(writer, contract.CreatedType);
          writer.WritePropertyName(JsonTypeReflector.ValuePropertyName);
          writer.WriteValue(value);
          writer.WriteEndObject();
          return;
        }
      }

      writer.WriteValue(value);
    }

    private bool CalculatePropertyDetails(JsonProperty property, ref JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, object target, out bool useExistingValue, out object currentValue, out JsonContract propertyContract, out bool gottenCurrentValue)
    {
      currentValue = null;
      useExistingValue = false;
      propertyContract = null;
      gottenCurrentValue = false;

      if (property.Ignored)
      {
        reader.Skip();
        return true;
      }

      ObjectCreationHandling objectCreationHandling =
        property.ObjectCreationHandling.GetValueOrDefault(Serializer.ObjectCreationHandling);

      if ((objectCreationHandling == ObjectCreationHandling.Auto || objectCreationHandling == ObjectCreationHandling.Reuse)
          && (reader.TokenType == JsonToken.StartArray || reader.TokenType == JsonToken.StartObject)
          && property.Readable)
      {
        currentValue = property.ValueProvider.GetValue(target);
        gottenCurrentValue = true;

        useExistingValue = (currentValue != null
                            && !property.PropertyType.IsArray
                            && !ReflectionUtils.InheritsGenericDefinition(property.PropertyType, typeof (ReadOnlyCollection<>))
                            && !property.PropertyType.IsValueType());
      }

      if (!property.Writable && !useExistingValue)
      {
        reader.Skip();
        return true;
      }

      // test tokentype here because null might not be convertable to some types, e.g. ignoring null when applied to DateTime
      if (property.NullValueHandling.GetValueOrDefault(Serializer.NullValueHandling) == NullValueHandling.Ignore && reader.TokenType == JsonToken.Null)
      {
        reader.Skip();
        return true;
      }

      // test tokentype here because default value might not be convertable to actual type, e.g. default of "" for DateTime
      if (HasFlag(property.DefaultValueHandling.GetValueOrDefault(Serializer.DefaultValueHandling), DefaultValueHandling.Ignore)
          && JsonReader.IsPrimitiveToken(reader.TokenType)
          && MiscellaneousUtils.ValueEquals(reader.Value, property.DefaultValue))
      {
        reader.Skip();
        return true;
      }

      if (property.PropertyContract == null)
        property.PropertyContract = GetContractSafe(property.PropertyType);

      if (currentValue == null)
      {
        propertyContract = property.PropertyContract;
      }
      else
      {
        propertyContract = GetContractSafe(currentValue.GetType());

        if (propertyContract != property.PropertyContract)
          propertyConverter = GetConverter(propertyContract, property.MemberConverter, containerContract, containerProperty);
      }

      return false;
    }

		private bool ShouldSerialize(JsonWriter writer, JsonProperty property, object target)
		{
			if (property.ShouldSerialize == null)
				return true;

			bool shouldSerialize = property.ShouldSerialize(target);

			if (TraceWriter != null && TraceWriter.LevelFilter >= TraceLevel.Verbose)
				TraceWriter.Trace(TraceLevel.Verbose, JsonPosition.FormatMessage(null, writer.Path, "ShouldSerialize result for property '{0}' on {1}: {2}".FormatWith(CultureInfo.InvariantCulture, property.PropertyName, property.DeclaringType, shouldSerialize)), null);

			return shouldSerialize;
		}

		private void SerializeDictionary(JsonWriter writer, IDictionary values, JsonDictionaryContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
		{
			IWrappedDictionary wrappedDictionary = values as IWrappedDictionary;
			object underlyingDictionary = wrappedDictionary != null ? wrappedDictionary.UnderlyingDictionary : values;

			OnSerializing(writer, contract, underlyingDictionary);
			_serializeStack.Add(underlyingDictionary);

			WriteObjectStart(writer, underlyingDictionary, contract, member, collectionContract, containerProperty);

			if (contract.ItemContract == null)
				contract.ItemContract = Serializer._contractResolver.ResolveContract(contract.DictionaryValueType ?? typeof(object));

			if (contract.KeyContract == null)
				contract.KeyContract = Serializer._contractResolver.ResolveContract(contract.DictionaryKeyType ?? typeof(object));

			int initialDepth = writer.Top;

			foreach (DictionaryEntry entry in values)
			{
				bool escape;
				string propertyName = GetPropertyName(writer, entry, contract.KeyContract, out escape);

				propertyName = (contract.PropertyNameResolver != null)
								 ? contract.PropertyNameResolver(propertyName)
								 : propertyName;

				try
				{
					object value = entry.Value;
					JsonContract valueContract = contract.FinalItemContract ?? GetContractSafe(value);

					if (ShouldWriteReference(value, null, valueContract, contract, member))
					{
						writer.WritePropertyName(propertyName, escape);
						WriteReference(writer, value);
					}
					else
					{
						if (!CheckForCircularReference(writer, value, null, valueContract, contract, member))
							continue;

						writer.WritePropertyName(propertyName, escape);

						SerializeValue(writer, value, valueContract, null, contract, member);
					}
				}
				catch (Exception ex)
				{
					if (IsErrorHandled(underlyingDictionary, contract, propertyName, null, writer.ContainerPath, ex))
						HandleError(writer, initialDepth);
					else
						throw;
				}
			}

			writer.WriteEndObject();

			_serializeStack.RemoveAt(_serializeStack.Count - 1);

			OnSerialized(writer, contract, underlyingDictionary);
		}

		private void SerializeDynamic(JsonWriter writer, IDynamicMetaObjectProvider value, JsonDynamicContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
		{
			OnSerializing(writer, contract, value);
			_serializeStack.Add(value);

			WriteObjectStart(writer, value, contract, member, collectionContract, containerProperty);

			int initialDepth = writer.Top;

			for (int index = 0; index < contract.Properties.Count; index++)
			{
				JsonProperty property = contract.Properties[index];

				// only write non-dynamic properties that have an explicit attribute
				if (property.HasMemberAttribute)
				{
					try
					{
						object memberValue;
						JsonContract memberContract;

						if (!CalculatePropertyValues(writer, value, contract, member, property, out memberContract, out memberValue))
							continue;

						property.WritePropertyName(writer);
						SerializeValue(writer, memberValue, memberContract, property, contract, member);
					}
					catch (Exception ex)
					{
						if (IsErrorHandled(value, contract, property.PropertyName, null, writer.ContainerPath, ex))
							HandleError(writer, initialDepth);
						else
							throw;
					}
				}
			}

			foreach (string memberName in value.GetDynamicMemberNames())
			{
				object memberValue;
				if (contract.TryGetMember(value, memberName, out memberValue))
				{
					try
					{
						JsonContract valueContract = GetContractSafe(memberValue);

						if (!ShouldWriteDynamicProperty(memberValue))
							continue;

						if (CheckForCircularReference(writer, memberValue, null, valueContract, contract, member))
						{
							string resolvedPropertyName = (contract.PropertyNameResolver != null)
															? contract.PropertyNameResolver(memberName)
															: memberName;

							writer.WritePropertyName(resolvedPropertyName);
							SerializeValue(writer, memberValue, valueContract, null, contract, member);
						}
					}
					catch (Exception ex)
					{
						if (IsErrorHandled(value, contract, memberName, null, writer.ContainerPath, ex))
							HandleError(writer, initialDepth);
						else
							throw;
					}
				}
			}

			writer.WriteEndObject();

			_serializeStack.RemoveAt(_serializeStack.Count - 1);
			OnSerialized(writer, contract, value);
		}

		private bool WriteStartArray(JsonWriter writer, object values, JsonArrayContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
		{
			bool isReference = ResolveIsReference(contract, member, containerContract, containerProperty) ?? HasFlag(Serializer._preserveReferencesHandling, PreserveReferencesHandling.Arrays);
			bool includeTypeDetails = ShouldWriteType(TypeNameHandling.Arrays, contract, member, containerContract, containerProperty);
			bool writeMetadataObject = isReference || includeTypeDetails;

			if (writeMetadataObject)
			{
				writer.WriteStartObject();

				if (isReference)
				{
					WriteReferenceIdProperty(writer, contract.UnderlyingType, values);
				}
				if (includeTypeDetails)
				{
					WriteTypeProperty(writer, values.GetType());
				}
				writer.WritePropertyName(JsonTypeReflector.ArrayValuesPropertyName, false);
			}

			if (contract.ItemContract == null)
				contract.ItemContract = Serializer._contractResolver.ResolveContract(contract.CollectionItemType ?? typeof(object));

			return writeMetadataObject;
		}

		private void SerializeMultidimensionalArray(JsonWriter writer, Array values, JsonArrayContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
		{
			OnSerializing(writer, contract, values);

			_serializeStack.Add(values);

			bool hasWrittenMetadataObject = WriteStartArray(writer, values, contract, member, collectionContract, containerProperty);

			SerializeMultidimensionalArray(writer, values, contract, member, writer.Top, new int[0]);

			if (hasWrittenMetadataObject)
				writer.WriteEndObject();

			_serializeStack.RemoveAt(_serializeStack.Count - 1);

			OnSerialized(writer, contract, values);
		}

		private void SerializeConvertable(JsonWriter writer, JsonConverter converter, object value, JsonContract contract, JsonContainerContract collectionContract, JsonProperty containerProperty)
		{
			if (ShouldWriteReference(value, null, contract, collectionContract, containerProperty))
			{
				WriteReference(writer, value);
			}
			else
			{
				if (!CheckForCircularReference(writer, value, null, contract, collectionContract, containerProperty))
					return;

				_serializeStack.Add(value);

				if (TraceWriter != null && TraceWriter.LevelFilter >= TraceLevel.Info)
					TraceWriter.Trace(TraceLevel.Info, JsonPosition.FormatMessage(null, writer.Path, "Started serializing {0} with converter {1}.".FormatWith(CultureInfo.InvariantCulture, value.GetType(), converter.GetType())), null);

				converter.WriteJson(writer, value, GetInternalSerializer());

				if (TraceWriter != null && TraceWriter.LevelFilter >= TraceLevel.Info)
					TraceWriter.Trace(TraceLevel.Info, JsonPosition.FormatMessage(null, writer.Path, "Finished serializing {0} with converter {1}.".FormatWith(CultureInfo.InvariantCulture, value.GetType(), converter.GetType())), null);

				_serializeStack.RemoveAt(_serializeStack.Count - 1);
			}
		}

        private void SerializeList(JsonWriter writer, IEnumerable values, JsonArrayContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
        {
            IWrappedCollection wrappedCollection = values as IWrappedCollection;
            object underlyingList = wrappedCollection != null ? wrappedCollection.UnderlyingCollection : values;

            OnSerializing(writer, contract, underlyingList);

            _serializeStack.Add(underlyingList);

            bool hasWrittenMetadataObject = WriteStartArray(writer, underlyingList, contract, member, collectionContract, containerProperty);

            writer.WriteStartArray();

            int initialDepth = writer.Top;

            int index = 0;
            IEnumerator enumerator;
            try
            {
                enumerator = values.GetEnumerator();
            }
            catch (Exception e)
            {
                throw new InvalidOperationException("Could not get enumerator for property: " + member, e);
            }
            using (enumerator as IDisposable)
            {
                while (true)
                {
                    try
                    {
                        if (enumerator.MoveNext() == false)
                            break;
                    }
                    catch (Exception e)
                    {
                        throw new InvalidOperationException("Could not move to next value for property: " + member, e);

                    }
                    object value;
                    try
                    {
                        value = enumerator.Current;
                    }
                    catch (Exception e)
                    {
                        throw new InvalidOperationException("Could not get current value for property: " + member, e);

                    }
                    try
                    {
                        JsonContract valueContract = contract.FinalItemContract ?? GetContractSafe(value);

                        if (ShouldWriteReference(value, null, valueContract, contract, member))
                        {
                            WriteReference(writer, value);
                        }
                        else
                        {
                            if (CheckForCircularReference(writer, value, null, valueContract, contract, member))
                            {
                                SerializeValue(writer, value, valueContract, null, contract, member);
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        if (IsErrorHandled(underlyingList, contract, index, null, writer.ContainerPath, ex))
                            HandleError(writer, initialDepth);
                        else
                            throw;
                    }
                    finally
                    {
                        index++;
                    }
                }
            }

            writer.WriteEndArray();

            if (hasWrittenMetadataObject)
                writer.WriteEndObject();

            _serializeStack.RemoveAt(_serializeStack.Count - 1);

            OnSerialized(writer, contract, underlyingList);
        }

        private void WriteObjectStart(JsonWriter writer, object value, JsonContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
        {
            writer.WriteStartObject();

            bool isReference = ResolveIsReference(contract, member, collectionContract, containerProperty) ?? HasFlag(Serializer._preserveReferencesHandling, PreserveReferencesHandling.Objects);
            // don't make readonly fields the referenced value because they can't be deserialized to
            if (isReference && (member == null || member.Writable))
            {
                WriteReferenceIdProperty(writer, contract.UnderlyingType, value);
            }
            if (ShouldWriteType(TypeNameHandling.Objects, contract, member, collectionContract, containerProperty))
            {
                WriteTypeProperty(writer, contract.UnderlyingType);
            }
        }

        private void SerializeObject(JsonWriter writer, object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
        {
            OnSerializing(writer, contract, value);

            _serializeStack.Add(value);

            WriteObjectStart(writer, value, contract, member, collectionContract, containerProperty);

            int initialDepth = writer.Top;

            for (int index = 0; index < contract.Properties.Count; index++)
            {
                JsonProperty property = contract.Properties[index];
                try
                {
                    object memberValue;
                    JsonContract memberContract;

                    if (!CalculatePropertyValues(writer, value, contract, member, property, out memberContract, out memberValue))
                        continue;

                    property.WritePropertyName(writer);
                    SerializeValue(writer, memberValue, memberContract, property, contract, member);
                }
                catch (Exception ex)
                {
                    if (IsErrorHandled(value, contract, property.PropertyName, null, writer.ContainerPath, ex))
                        HandleError(writer, initialDepth);
                    else
                        throw;
                }
            }

            if (contract.ExtensionDataGetter != null)
            {
                IEnumerable<KeyValuePair<object, object>> extensionData = contract.ExtensionDataGetter(value);
                if (extensionData != null)
                {
                    foreach (KeyValuePair<object, object> e in extensionData)
                    {
                        JsonContract keyContract = GetContractSafe(e.Key);
                        JsonContract valueContract = GetContractSafe(e.Value);

                        bool escape;
                        string propertyName = GetPropertyName(writer, e.Key, keyContract, out escape);

                        if (ShouldWriteReference(e.Value, null, valueContract, contract, member))
                        {
                            writer.WritePropertyName(propertyName);
                            WriteReference(writer, e.Value);
                        }
                        else
                        {
                            if (!CheckForCircularReference(writer, e.Value, null, valueContract, contract, member))
                                continue;

                            writer.WritePropertyName(propertyName);

                            SerializeValue(writer, e.Value, valueContract, null, contract, member);
                        }
                    }
                }
            }

            if (beforeClosingObject != null)
                beforeClosingObject(value, writer);

            writer.WriteEndObject();

            _serializeStack.RemoveAt(_serializeStack.Count - 1);

            OnSerialized(writer, contract, value);
        }

    private object CreateDynamic(JsonReader reader, JsonDynamicContract contract, JsonProperty member, string id)
    {
      IDynamicMetaObjectProvider newObject;

      if (contract.UnderlyingType.IsInterface() || contract.UnderlyingType.IsAbstract())
        throw JsonSerializationException.Create(reader, "Could not create an instance of type {0}. Type is an interface or abstract class and cannot be instantated.".FormatWith(CultureInfo.InvariantCulture, contract.UnderlyingType));

      if (contract.DefaultCreator != null &&
        (!contract.DefaultCreatorNonPublic || Serializer.ConstructorHandling == ConstructorHandling.AllowNonPublicDefaultConstructor))
        newObject = (IDynamicMetaObjectProvider) contract.DefaultCreator();
      else
        throw JsonSerializationException.Create(reader, "Unable to find a default constructor to use for type {0}.".FormatWith(CultureInfo.InvariantCulture, contract.UnderlyingType));

      if (id != null)
        Serializer.ReferenceResolver.AddReference(this, id, newObject);

      contract.InvokeOnDeserializing(newObject, Serializer.Context);

      int initialDepth = reader.Depth;

      bool exit = false;
      do
      {
        switch (reader.TokenType)
        {
          case JsonToken.PropertyName:
            string memberName = reader.Value.ToString();

            try
            {
              if (!reader.Read())
                throw JsonSerializationException.Create(reader, "Unexpected end when setting {0}'s value.".FormatWith(CultureInfo.InvariantCulture, memberName));

              // first attempt to find a settable property, otherwise fall back to a dynamic set without type
              JsonProperty property = contract.Properties.GetClosestMatchProperty(memberName);

              if (property != null && property.Writable && !property.Ignored)
              {
                if (property.PropertyContract == null)
                  property.PropertyContract = GetContractSafe(property.PropertyType);

                JsonConverter propertyConverter = GetConverter(property.PropertyContract, property.MemberConverter, null, null);

                SetPropertyValue(property, propertyConverter, null, member, reader, newObject);
              }
              else
              {
                Type t = (JsonReader.IsPrimitiveToken(reader.TokenType)) ? reader.ValueType : typeof (IDynamicMetaObjectProvider);

                JsonContract dynamicMemberContract = GetContractSafe(t);
                JsonConverter dynamicMemberConverter = GetConverter(dynamicMemberContract, null, null, member);

                object value;
                if (dynamicMemberConverter != null && dynamicMemberConverter.CanRead)
                  value = dynamicMemberConverter.ReadJson(reader, t, null, GetInternalSerializer());
                else
                  value = CreateValueInternal(reader, t, dynamicMemberContract, null, null, member, null);

                newObject.TrySetMember(memberName, value);
              }
            }
            catch (Exception ex)
            {
              if (IsErrorHandled(newObject, contract, memberName, reader.Path, ex))
                HandleError(reader, true, initialDepth);
              else
                throw;
            }
            break;
          case JsonToken.EndObject:
            exit = true;
            break;
          default:
            throw JsonSerializationException.Create(reader, "Unexpected token when deserializing object: " + reader.TokenType);
        }
      } while (!exit && reader.Read());

      contract.InvokeOnDeserialized(newObject, Serializer.Context);

      return newObject;
    }

    private object PopulateList(IWrappedCollection wrappedList, JsonReader reader, JsonArrayContract contract, JsonProperty containerProperty, string id)
    {
      object list = wrappedList.UnderlyingCollection;

      if (id != null)
        Serializer.ReferenceResolver.AddReference(this, id, list);

      // can't populate an existing array
      if (wrappedList.IsFixedSize)
      {
        reader.Skip();
        return list;
      }

      contract.InvokeOnDeserializing(list, Serializer.Context);

      int initialDepth = reader.Depth;

      JsonContract collectionItemContract = GetContractSafe(contract.CollectionItemType);
      JsonConverter collectionItemConverter = GetConverter(collectionItemContract, null, contract, containerProperty);

      int? previousErrorIndex = null;

      while (true)
      {
        try
        {
          if (ReadForType(reader, collectionItemContract, collectionItemConverter != null))
          {
            switch (reader.TokenType)
            {
              case JsonToken.EndArray:
                contract.InvokeOnDeserialized(list, Serializer.Context);

                return list;
              case JsonToken.Comment:
                break;
              default:
                object value;

                if (collectionItemConverter != null && collectionItemConverter.CanRead)
                  value = collectionItemConverter.ReadJson(reader, contract.CollectionItemType, null, GetInternalSerializer());
                else
                  value = CreateValueInternal(reader, contract.CollectionItemType, collectionItemContract, null, contract, containerProperty, null);

                wrappedList.Add(value);
                break;
            }
          }
          else
          {
            break;
          }
        }
        catch (Exception ex)
        {
          JsonPosition errorPosition = reader.GetPosition(initialDepth);

          if (IsErrorHandled(list, contract, errorPosition.Position, reader.Path, ex))
          {
            HandleError(reader, true, initialDepth);

            if (previousErrorIndex != null && previousErrorIndex == errorPosition.Position)
            {
              // reader index has not moved since previous error handling
              // break out of reading array to prevent infinite loop
              throw JsonSerializationException.Create(reader, "Infinite loop detected from error handling.", ex);
            }
            else
            {
              previousErrorIndex = errorPosition.Position;
            }
          }
          else
          {
            throw;
          }
        }
      }

      throw JsonSerializationException.Create(reader, "Unexpected end when deserializing array.");
    }

    private object PopulateDictionary(IWrappedDictionary wrappedDictionary, JsonReader reader, JsonDictionaryContract contract, JsonProperty containerProperty, string id)
    {
      object dictionary = wrappedDictionary.UnderlyingDictionary;

      if (id != null)
        Serializer.ReferenceResolver.AddReference(this, id, dictionary);

      contract.InvokeOnDeserializing(dictionary, Serializer.Context);

      int initialDepth = reader.Depth;

      if (contract.KeyContract == null)
        contract.KeyContract = GetContractSafe(contract.DictionaryKeyType);

      if (contract.ItemContract == null)
        contract.ItemContract = GetContractSafe(contract.DictionaryValueType);

      JsonConverter dictionaryValueConverter = contract.ItemConverter ?? GetConverter(contract.ItemContract, null, contract, containerProperty);

      do
      {
        switch (reader.TokenType)
        {
          case JsonToken.PropertyName:
            object keyValue = reader.Value;
            try
            {
              try
              {
                keyValue = EnsureType(reader, keyValue, CultureInfo.InvariantCulture, contract.KeyContract, contract.DictionaryKeyType);
              }
              catch (Exception ex)
              {
                throw JsonSerializationException.Create(reader, "Could not convert string '{0}' to dictionary key type '{1}'. Create a TypeConverter to convert from the string to the key type object.".FormatWith(CultureInfo.InvariantCulture, reader.Value, contract.DictionaryKeyType), ex);
              }

              if (!ReadForType(reader, contract.ItemContract, dictionaryValueConverter != null))
                throw JsonSerializationException.Create(reader, "Unexpected end when deserializing object.");

              object itemValue;
              if (dictionaryValueConverter != null && dictionaryValueConverter.CanRead)
                itemValue = dictionaryValueConverter.ReadJson(reader, contract.DictionaryValueType, null, GetInternalSerializer());
              else
                itemValue = CreateValueInternal(reader, contract.DictionaryValueType, contract.ItemContract, null, contract, containerProperty, null);

              wrappedDictionary[keyValue] = itemValue;
            }
            catch (Exception ex)
            {
              if (IsErrorHandled(dictionary, contract, keyValue, reader.Path, ex))
                HandleError(reader, true, initialDepth);
              else
                throw;
            }
            break;
          case JsonToken.Comment:
            break;
          case JsonToken.EndObject:
            contract.InvokeOnDeserialized(dictionary, Serializer.Context);

            return dictionary;
          default:
            throw JsonSerializationException.Create(reader, "Unexpected token when deserializing object: " + reader.TokenType);
        }
      } while (reader.Read());

      throw JsonSerializationException.Create(reader, "Unexpected end when deserializing object.");
    }

    private bool ShouldSetPropertyValue(JsonProperty property, object value)
    {
      if (property.NullValueHandling.GetValueOrDefault(Serializer.NullValueHandling) == NullValueHandling.Ignore && value == null)
        return false;

      if (HasFlag(property.DefaultValueHandling.GetValueOrDefault(Serializer.DefaultValueHandling), DefaultValueHandling.Ignore)
        && MiscellaneousUtils.ValueEquals(value, property.DefaultValue))
        return false;

      if (!property.Writable)
        return false;

      return true;
    }