Attach ItemResolveEventArgs to BaseItem so providers can access them at any time

MediaBrowser.Controller/Entities/BaseItem.cs

@@ -1,4 +1,5 @@
 using MediaBrowser.Model.Entities;
+using MediaBrowser.Controller.Library;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -7,6 +8,13 @@ namespace MediaBrowser.Controller.Entities
 {
     public abstract class BaseItem : BaseEntity, IHasProviderIds
     {
+        /// <summary>
+        /// We attach these to the item so that we only ever have to hit the file system once
+        /// (this includes the children of the containing folder)
+        /// Use ResolveArgs.FileSystemChildren to check for the existence of files instead of File.Exists
+        /// </summary>
+        public ItemResolveEventArgs ResolveArgs { get; set; }
+
         public string SortName { get; set; }
 
         /// <summary>

MediaBrowser.Controller/Entities/Folder.cs

@@ -171,6 +171,10 @@ namespace MediaBrowser.Controller.Entities
                     if (currentChild.IsChanged(child))
                     {
                         changed = true;
+                        //update resolve args and refresh meta
+                        //  Note - we are refreshing the existing child instead of the newly found one so the "Except" operation below
+                        //  will identify this item as the same one
+                        currentChild.ResolveArgs = child.ResolveArgs;
                         currentChild.RefreshMetadata();
                         //save it in repo...
                         validChildren.Add(currentChild);

MediaBrowser.Controller/Kernel.cs

@@ -129,6 +129,7 @@ namespace MediaBrowser.Controller
 
                 if (item != null)
                 {
+                    item.ResolveArgs = args;
                     return item;
                 }
             }
@@ -160,6 +161,7 @@ namespace MediaBrowser.Controller
 
         void RootFolder_ChildrenChanged(object sender, ChildrenChangedEventArgs e)
         {
+            Logger.LogDebugInfo("Root Folder Children Changed.  Added: " + e.ItemsAdded.Count + " Removed: " + e.ItemsRemoved.Count());
             //re-start the directory watchers
             DirectoryWatchers.Stop();
             DirectoryWatchers.Start();