XDocumentWrapper
using Newtonsoft.Json.Utilities;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Xml;
using System.Xml.Linq;
namespace Newtonsoft.Json.Converters
{
    [System.Runtime.CompilerServices.NullableContext(1)]
    [System.Runtime.CompilerServices.Nullable(0)]
    internal class XDocumentWrapper : XContainerWrapper, IXmlDocument, IXmlNode
    {
        private XDocument Document => (XDocument)base.WrappedNode;
        public override List<IXmlNode> ChildNodes {
            get {
                List<IXmlNode> childNodes = base.ChildNodes;
                if (Document.Declaration != null && (childNodes.Count == 0 || childNodes[0].NodeType != XmlNodeType.XmlDeclaration))
                    childNodes.Insert(0, new XDeclarationWrapper(Document.Declaration));
                return childNodes;
            }
        }
        protected override bool HasChildNodes {
            get {
                if (base.HasChildNodes)
                    return true;
                return Document.Declaration != null;
            }
        }
        [System.Runtime.CompilerServices.Nullable(2)]
        public IXmlElement DocumentElement {
            [System.Runtime.CompilerServices.NullableContext(2)]
            get {
                if (Document.Root == null)
                    return null;
                return new XElementWrapper(Document.Root);
            }
        }
        public XDocumentWrapper(XDocument document)
            : base(document)
        {
        }
        public IXmlNode CreateComment([System.Runtime.CompilerServices.Nullable(2)] string text)
        {
            return new XObjectWrapper(new XComment(text));
        }
        public IXmlNode CreateTextNode([System.Runtime.CompilerServices.Nullable(2)] string text)
        {
            return new XObjectWrapper(new XText(text));
        }
        public IXmlNode CreateCDataSection([System.Runtime.CompilerServices.Nullable(2)] string data)
        {
            return new XObjectWrapper(new XCData(data));
        }
        public IXmlNode CreateWhitespace([System.Runtime.CompilerServices.Nullable(2)] string text)
        {
            return new XObjectWrapper(new XText(text));
        }
        public IXmlNode CreateSignificantWhitespace([System.Runtime.CompilerServices.Nullable(2)] string text)
        {
            return new XObjectWrapper(new XText(text));
        }
        [System.Runtime.CompilerServices.NullableContext(2)]
        [return: System.Runtime.CompilerServices.Nullable(1)]
        public IXmlNode CreateXmlDeclaration(string version, string encoding, string standalone)
        {
            return new XDeclarationWrapper(new XDeclaration(version, encoding, standalone));
        }
        [System.Runtime.CompilerServices.NullableContext(2)]
        [return: System.Runtime.CompilerServices.Nullable(1)]
        public IXmlNode CreateXmlDocumentType(string name, string publicId, string systemId, string internalSubset)
        {
            return new XDocumentTypeWrapper(new XDocumentType(name, publicId, systemId, internalSubset));
        }
        public IXmlNode CreateProcessingInstruction(string target, [System.Runtime.CompilerServices.Nullable(2)] string data)
        {
            return new XProcessingInstructionWrapper(new XProcessingInstruction(target, data));
        }
        public IXmlElement CreateElement(string elementName)
        {
            return new XElementWrapper(new XElement(elementName));
        }
        public IXmlElement CreateElement(string qualifiedName, string namespaceUri)
        {
            return new XElementWrapper(new XElement(XName.Get(MiscellaneousUtils.GetLocalName(qualifiedName), namespaceUri)));
        }
        public IXmlNode CreateAttribute(string name, [System.Runtime.CompilerServices.Nullable(2)] string value)
        {
            return new XAttributeWrapper(new XAttribute(name, value));
        }
        public IXmlNode CreateAttribute(string qualifiedName, string namespaceUri, [System.Runtime.CompilerServices.Nullable(2)] string value)
        {
            return new XAttributeWrapper(new XAttribute(XName.Get(MiscellaneousUtils.GetLocalName(qualifiedName), namespaceUri), value));
        }
        public override IXmlNode AppendChild(IXmlNode newChild)
        {
            XDeclarationWrapper xDeclarationWrapper = newChild as XDeclarationWrapper;
            if (xDeclarationWrapper != null) {
                Document.Declaration = xDeclarationWrapper.Declaration;
                return xDeclarationWrapper;
            }
            return base.AppendChild(newChild);
        }
    }
}