fixed apptype detection during update

NzbDrone.Update/UpdateEngine/BackupAndRestore.cs

@@ -0,0 +1,38 @@
+using NLog;
+using NzbDrone.Common;
+
+namespace NzbDrone.Update.UpdateEngine
+{
+    public interface IBackupAndRestore
+    {
+        void BackUp(string source);
+        void Restore(string target);
+    }
+
+    public class BackupAndRestore : IBackupAndRestore
+    {
+        private readonly IDiskProvider _diskProvider;
+        private readonly IEnvironmentProvider _environmentProvider;
+        private readonly Logger _logger;
+
+        public BackupAndRestore(IDiskProvider diskProvider, IEnvironmentProvider environmentProvider, Logger logger)
+        {
+            _diskProvider = diskProvider;
+            _environmentProvider = environmentProvider;
+            _logger = logger;
+        }
+
+        public void BackUp(string source)
+        {
+            _logger.Info("Creating backup of existing installation");
+            _diskProvider.CopyDirectory(source, _environmentProvider.GetUpdateBackUpFolder());
+        }
+
+        public void Restore(string target)
+        {
+            //TODO:this should ignore single file failures.
+            _logger.Info("Attempting to rollback upgrade");
+            _diskProvider.CopyDirectory(_environmentProvider.GetUpdateBackUpFolder(), target);
+        }
+    }
+}