Fixing bugs, which I introduced with the 'MoveNext' issue fixes

Last week's MoveNext() fix actually turns out to be too restrictive and yielded a subtle bug.

Symptom:

Razor Code of this format:

    @{
      var image = @Model.Media("relatedMedia");
    }
    <<mg src="http://mce_host/forum/.../@image.UmbracoFile" alt="@image.Name" />

only returns the media path with first application launch. Subsequent calls return null. I introduced this as a bug in the last set up 'MoveNext issue' fixes.

In  ExamineBackedMedia.cs change
48:51, from,   
            if (media != null)
            {
				if (media.MoveNext())
					return new ExamineBackedMedia(media.Current);
to
            if (media != null)
            {
				media.MoveNext();
				if (media.Current != null)
					return new ExamineBackedMedia(media.Current);

This is because the relevant XPathNodeIterator is cached, and once the index is advanced its state is retained.

I am also going to relax the remaining restrictions involving MoveNext as follows:

Again in  ExamineBackedMedia.cs change:
64:67, from,
			XPathNodeIterator xpi = xpath.Select(".");
            //add the attributes e.g. id, parentId etc
			if (xpi.MoveNext())
	            if (xpi.Current.HasAttributes)
to
			XPathNodeIterator xpi = xpath.Select(".");
            //add the attributes e.g. id, parentId etc
			xpi.MoveNext ();
			if (xpi.Current != null)			
	            if (xpi.Current.HasAttributes)
	            
110:113 from,
            var media = umbraco.library.GetMedia(this.Id, true);
            if (media != null && media.MoveNext())
            {
                XPathNavigator xpath = media.Current;
                ...
to
            var media = umbraco.library.GetMedia(this.Id, true);
            if (media != null)
            {
				media.MoveNext();
				if (media.Current != null)
				{
					XPathNavigator xpath = media.Current;
	                var result = xpath.SelectChildren(XPathNodeType.Element);
	                while (result.MoveNext())
	                {
	                    if (result.Current != null && !result.Current.HasAttributes)
	                    {
	                        if (string.Equals(result.Current.Name, alias))
	                        {
	                            string value = result.Current.Value;
	                            if (string.IsNullOrEmpty(value))
	                            {
	                                value = result.Current.OuterXml;
	                            }
	                            Values.Add(result.Current.Name, value);
	                            propertyExists = true;
	                            return new PropertyResult(alias, value, Guid.Empty);
	                        }
	                    }
	                }
				}
            }

370:373, from, 
            var media = umbraco.library.GetMedia(ParentId, true);                           	            
            if (media != null && media.MoveNext())
            {
                var children = media.Current.SelectChildren(XPathNodeType.Element);
                ...
to
            if (media != null)
            {
				media.MoveNext();
				if (media.Current != null)
				{
					var children = media.Current.SelectChildren(XPathNodeType.Element);
	                List mediaList = new List();
	                while (children != null && children.Current != null)
	                {
	                    if (children.MoveNext())
	                    {
	                        if (children.Current.Name != "contents")
	                        {
	                            //make sure it's actually a node, not a property 
	                            if (!string.IsNullOrEmpty(children.Current.GetAttribute("path", "")) &&
	                                !string.IsNullOrEmpty(children.Current.GetAttribute("id", "")) &&
	                                !string.IsNullOrEmpty(children.Current.GetAttribute("version", "")))
	                            {
	                                mediaList.Add(new ExamineBackedMedia(children.Current));
	                            }
	                        }
	                    }
	                    else
	                    {
	                        break;
	                    }
	                }
	                return mediaList;
				}
            }
            
DynamicXml.cs, 31:33
from,
            if (xpni != null)
            {                
                if (xpni.MoveNext())
                {
                    var xml = xpni.Current.OuterXml;  
to
            if (xpni != null)
            {
				xpni.MoveNext();
				if (xpni.Current != null)
                {
                    var xml = xpni.Current.OuterXml;          
                                            	            

 

Also change function GetCurrentNodeFromIterator in .../umbraco/businesslogic/xmlHelper.cs to:

		//this is very mono specific at the moment
		public static XmlNode GetCurrentNodeFromIterator(XPathNodeIterator xpi)
		{
			if (xpi != null)
			{
				xpi.MoveNext();
				if (xpi.Current != null)
					return ((IHasXmlNode)xpi.Current).GetNode();
			}

			return null;
		}