implements the file moves ui

src/Yavsc.Abstract/FileSystem/AbstractFileSystemHelpers.cs

@@ -60,6 +60,12 @@ namespace Yavsc.Helpers
             UserDirectoryInfo di = new UserDirectoryInfo(UserFilesDirName, userName, subdir);
             return di;
         }
+        public static bool IsRegularFile(string userName, string subdir)
+        {
+            FileInfo fi = new FileInfo( Path.Combine(Path.Combine(UserFilesDirName, userName), subdir));
+            return fi.Exists;
+        }
+
 
         // Server side only supports POSIX file systems
         public const char RemoteDirectorySeparator = '/';

src/Yavsc.Abstract/FileSystem/FsOperationInfo.cs

@@ -1,7 +1,18 @@
 namespace Yavsc.Helpers
 {
+    public enum ErrorCode {
+        NotFound,
+        InternalError,
+        DestExists, 
+        InvalidRequest
+    }
+
     public class FsOperationInfo {
+
         public bool Done { get; set; } = false;
-        public string Error { get; set; }
+
+        public ErrorCode ErrorCode { get; set; }
+        public string ErrorMessage { get; set; }
+
     }
 }