Stanza.cs

using System;
using System.Xml;
 
namespace Waher.Networking.XMPP.Server
{
    public class Stanza
    {
        private readonly XmlElement rootElement;
        private XmlElement stanzaElement = null;
        private readonly string xml;
        private string content;
        private readonly int contentStart;
        private readonly int contentLen;
 
        public Stanza(XmlElement RootElement, string Xml, int ContentStart, int ContentLen)
        {
            this.rootElement = RootElement;
            this.xml = Xml;
            this.contentStart = ContentStart;
            this.contentLen = ContentLen;
            this.content = null;
        }
 
        public Stanza(XmlElement RootElement, XmlElement StanzaElement, string Xml)
        {
            this.rootElement = RootElement;
            this.stanzaElement = StanzaElement;
            this.xml = Xml;
            this.content = null;
            this.contentStart = -1;
            this.contentLen = 0;
        }
 
        public string Content
        {
            get
            {
                if (this.content is null)
                {
                    if (this.contentStart < 0)
                    {
                        XmlElement E = this.StanzaElement;
                        if (E is null)
                            this.content = string.Empty;
                        else
                            this.content = E.InnerXml;
                    }
                    else if (this.contentLen <= 0)
                        this.content = string.Empty;
                    else
                        this.content = this.xml.Substring(this.contentStart, this.contentLen);
                }
 
                return this.content;
            }
        }
 
        public bool HasContent
        {
            get
            {
                if (!(this.content is null))
                    return !string.IsNullOrEmpty(this.content);
 
                if (this.contentStart < 0)
                {
                    XmlElement E = this.StanzaElement;
                    if (E is null)
                        return false;
                    else
                    {
                        foreach (XmlNode N in E.ChildNodes)
                        {
                            if (N is XmlElement)
                                return true;
                        }
 
                        return false;
                    }
                }
                else if (this.contentLen <= 0)
                    return false;
                else
                    return true;
            }
        }
 
        public XmlElement StanzaElement
        {
            get
            {
                if (this.stanzaElement is null)
                {
                    foreach (XmlNode N in this.rootElement.ChildNodes)
                    {
                        if (N is XmlElement E)
                        {
                            this.stanzaElement = E;
                            break;
                        }
                    }
                }
 
                return this.stanzaElement;
            }
        }
    }
}