System.Xml.XmlTextReaderImpl.HandleGeneralEntityReference C# (CSharp) Method

        private EntityType HandleGeneralEntityReference(string name, bool isInAttributeValue, bool pushFakeEntityIfNullResolver, int entityStartLinePos)
        {
            IDtdEntityInfo entity = null;

            if (_dtdInfo == null && _fragmentParserContext != null && _fragmentParserContext.HasDtdInfo && _dtdProcessing == DtdProcessing.Parse)
            {
                ParseDtdFromParserContext();
            }

            if (_dtdInfo == null ||
                 ((entity = _dtdInfo.LookupEntity(name)) == null))
            {
                if (_disableUndeclaredEntityCheck)
                {
                    SchemaEntity schemaEntity = new SchemaEntity(new XmlQualifiedName(name), false);
                    schemaEntity.Text = string.Empty;
                    entity = schemaEntity;
                }
                else
                    Throw(SR.Xml_UndeclaredEntity, name, _ps.LineNo, entityStartLinePos);
            }

            if (entity.IsUnparsedEntity)
            {
                if (_disableUndeclaredEntityCheck)
                {
                    SchemaEntity schemaEntity = new SchemaEntity(new XmlQualifiedName(name), false);
                    schemaEntity.Text = string.Empty;
                    entity = schemaEntity;
                }
                else
                    Throw(SR.Xml_UnparsedEntityRef, name, _ps.LineNo, entityStartLinePos);
            }

            if (_standalone && entity.IsDeclaredInExternal)
            {
                Throw(SR.Xml_ExternalEntityInStandAloneDocument, entity.Name, _ps.LineNo, entityStartLinePos);
            }

            if (entity.IsExternal)
            {
                if (isInAttributeValue)
                {
                    Throw(SR.Xml_ExternalEntityInAttValue, name, _ps.LineNo, entityStartLinePos);
                    return EntityType.Skipped;
                }

                if (_parsingMode == ParsingMode.SkipContent)
                {
                    return EntityType.Skipped;
                }

                if (IsResolverNull)
                {
                    if (pushFakeEntityIfNullResolver)
                    {
                        PushExternalEntity(entity);
                        _curNode.entityId = _ps.entityId;
                        return EntityType.FakeExpanded;
                    }
                    return EntityType.Skipped;
                }
                else
                {
                    PushExternalEntity(entity);
                    _curNode.entityId = _ps.entityId;
                    return (isInAttributeValue && _validatingReaderCompatFlag) ? EntityType.ExpandedInAttribute : EntityType.Expanded;
                }
            }
            else
            {
                if (_parsingMode == ParsingMode.SkipContent)
                {
                    return EntityType.Skipped;
                }

                PushInternalEntity(entity);

                _curNode.entityId = _ps.entityId;
                return (isInAttributeValue && _validatingReaderCompatFlag) ? EntityType.ExpandedInAttribute : EntityType.Expanded;
            }
        }