Part of the fix for U4-1689

Adds an alternative to the naming of the media subfolders instead of using the PropertyId.

src/Umbraco.Core/Media/MediaSubFolders.cs

@@ -0,0 +1,60 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using Umbraco.Core.IO;
+
+namespace Umbraco.Core.Media
+{
+    /// <summary>
+    /// Internal singleton to handle the numbering of subfolders within the Media-folder.
+    /// When this class is initiated it will look for numbered subfolders and select the highest number,
+    /// which will be the start point for the naming of the next subfolders. If no subfolders exists
+    /// then the starting point will be 1000, ie. /media/1000/koala.jpg
+    /// </summary>
+    internal class MediaSubFolders
+    {
+        #region Singleton
+
+        private long _numberedFolder = 1000;//Default starting point
+        private static readonly ReaderWriterLockSlim ClearLock = new ReaderWriterLockSlim();
+        private static readonly Lazy<MediaSubFolders> Lazy = new Lazy<MediaSubFolders>(() => new MediaSubFolders());
+
+        public static MediaSubFolders Current { get { return Lazy.Value; } }
+
+        private MediaSubFolders()
+        {
+            var folders = new List<long>();
+            var fs = FileSystemProviderManager.Current.GetFileSystemProvider<MediaFileSystem>();
+            var directories = fs.GetDirectories("/");
+            if (directories.Any())
+            {
+                foreach (var directory in directories)
+                {
+                    long dirNum;
+                    if (long.TryParse(directory, out dirNum))
+                    {
+                        folders.Add(dirNum);
+                    }
+                }
+                long last = folders.OrderBy(x => x).Last();
+                _numberedFolder = last;
+            }
+        }
+
+        #endregion
+
+        /// <summary>
+        /// Returns an increment of the numbered media subfolders.
+        /// </summary>
+        /// <returns>A <see cref="System.Int64"/> value</returns>
+        public long Increment()
+        {
+            using (new ReadLock(ClearLock))
+            {
+                _numberedFolder++;
+                return _numberedFolder;
+            }
+        }
+    }
+}

src/Umbraco.Core/Models/ContentExtensions.cs

@@ -10,6 +10,7 @@ using System.Xml;
 using System.Xml.Linq;
 using Umbraco.Core.Configuration;
 using Umbraco.Core.IO;
+using Umbraco.Core.Media;
 using Umbraco.Core.Models.Membership;
 using Umbraco.Core.Persistence;
 using Umbraco.Core.Persistence.UnitOfWork;
@@ -109,9 +110,10 @@ namespace Umbraco.Core.Models
                 return;
 
             bool supportsResizing = false;
+            var numberedFolder = MediaSubFolders.Current.Increment();
             string fileName = UmbracoSettings.UploadAllowDirectories
-                                              ? Path.Combine(property.Id.ToString(), name)
-                                              : property.Id + "-" + name;
+                                              ? Path.Combine(numberedFolder.ToString(CultureInfo.InvariantCulture), name)
+                                              : numberedFolder + "-" + name;
             string extension = Path.GetExtension(name);
 
             var fs = FileSystemProviderManager.Current.GetFileSystemProvider<MediaFileSystem>();

src/Umbraco.Core/Umbraco.Core.csproj

@@ -139,6 +139,7 @@
     <Compile Include="Events\SendToPublishEventArgs.cs" />
     <Compile Include="IApplicationEventHandler.cs" />
     <Compile Include="MacroPropertyTypeResolver.cs" />
+    <Compile Include="Media\MediaSubFolders.cs" />
     <Compile Include="Models\ContentBase.cs" />
     <Compile Include="Models\ContentExtensions.cs" />
     <Compile Include="Enum.cs" />

src/umbraco.cms/businesslogic/datatype/FileHandlerData.cs

@@ -1,8 +1,10 @@
 using System;
+using System.Globalization;
 using System.IO;
 using System.Web;
 using System.Xml;
 using Umbraco.Core.IO;
+using Umbraco.Core.Media;
 using umbraco.cms.businesslogic.Files;
 using umbraco.cms.businesslogic.property;
 
@@ -55,9 +57,10 @@ namespace umbraco.cms.businesslogic.datatype
                     // handle upload
                     if (name != String.Empty)
                     {
+                        var numberedFolder = MediaSubFolders.Current.Increment();
                         string fileName = UmbracoSettings.UploadAllowDirectories
-                                              ? Path.Combine(PropertyId.ToString(), name)
-                                              : PropertyId + "-" + name;
+                                              ? Path.Combine(numberedFolder.ToString(CultureInfo.InvariantCulture), name)
+                                              : numberedFolder + "-" + name;
 
                         //fileName = Path.Combine(SystemDirectories.Media, fileName);
                         UmbracoFile um = UmbracoFile.Save(fileStream, fileName);