Add possibility to delete backup file when upgrading database

LiteDB/Engine/Engine/Recovery.cs

@@ -13,15 +13,16 @@ public partial class LiteEngine
         /// <summary>
         /// Recovery datafile using a rebuild process. Run only on "Open" database
         /// </summary>
-        private void Recovery(Collation collation)
+        private void Recovery(Collation collation, bool createBackup = true)
         {
             // run build service
             var rebuilder = new RebuildService(_settings);
             var options = new RebuildOptions
             {
                 Collation = collation,
                 Password = _settings.Password,
-                IncludeErrorReport = true
+                IncludeErrorReport = true,
+                CreateBackup = createBackup
             };
 
             // run rebuild process

LiteDB/Engine/Engine/Upgrade.cs

@@ -34,7 +34,7 @@ private void TryUpgrade()
             }
 
             // run rebuild process
-            this.Recovery(_settings.Collation);
+            this.Recovery(_settings.Collation, _settings.CreateBackupOnUpgrade);
         }
 
         /// <summary>

LiteDB/Engine/EngineSettings.cs

@@ -66,6 +66,11 @@ public class EngineSettings
         /// </summary>
         public bool Upgrade { get; set; } = false;
 
+        /// <summary>
+        /// If a upgrade is made a backup database is created.
+        /// </summary>
+        public bool CreateBackupOnUpgrade { get; set; } = true;
+
         /// <summary>
         /// Create new IStreamFactory for datafile
         /// </summary>

LiteDB/Engine/Services/RebuildService.cs

@@ -101,9 +101,16 @@ public long Rebuild(RebuildOptions options)
 
 
             // get difference size
-            return 
-                new FileInfo(backupFilename).Length -
+            var diff = new FileInfo(backupFilename).Length -
                 new FileInfo(_settings.Filename).Length;
+
+            if (!options.CreateBackup)
+            {
+                // Delete the backup file
+                File.Delete(backupFilename);
+            }
+
+            return diff;
         }
 
         /// <summary>

LiteDB/Engine/Structures/RebuildOptions.cs

@@ -26,6 +26,11 @@ public class RebuildOptions
         /// </summary>
         public Collation Collation { get; set; } = null;
 
+        /// <summary>
+        /// Should the rebuild create a backup
+        /// </summary>
+        public bool CreateBackup { get; set; } = true;
+
         /// <summary>
         /// When set true, if any problem occurs in rebuild, a _rebuild_errors collection
         /// will contains all errors found