Add FileHelper

Database/Collections/Upsert.cs

@@ -7,7 +7,7 @@ namespace LiteDB
     public partial class LiteCollection<T>
     {
         /// <summary>
-        /// Insert or Update a document in this collection. Returns false if not found document in collection
+        /// Insert or Update a document in this collection.
         /// </summary>
         public bool Upsert(T document)
         {
@@ -20,7 +20,7 @@ public bool Upsert(T document)
         }
 
         /// <summary>
-        /// Insert or Update a document in this collection. Returns false if not found document in collection
+        /// Insert or Update a document in this collection.
         /// </summary>
         public bool Upsert(BsonValue id, T document)
         {

Database/LiteDatabase.cs

@@ -199,13 +199,7 @@ public long Shrink(string password)
             if (_connectionString != null)
             {
                 // get temp file ("-temp" sufix)
-                var tempFile = Path.Combine(Path.GetDirectoryName(_connectionString.Filename), Path.GetFileNameWithoutExtension(_connectionString.Filename) + "-temp" + Path.GetExtension(_connectionString.Filename));
-
-                // if temp file exists, just delete (if is in-use exception will be throwed)
-                if(File.Exists(tempFile))
-                {
-                    File.Delete(tempFile);
-                }
+                var tempFile = FileHelper.GetTempFile(_connectionString.Filename);
 
                 // get temp disk based on temp file
                 var tempDisk = new FileDiskService(tempFile, false);

Engine/Disks/FileDiskService.cs

@@ -43,7 +43,7 @@ public FileDiskService(string filename, FileOptions options)
             _options = options;
 
             // journal filename
-            _journalFilename = Path.Combine(Path.GetDirectoryName(_filename), Path.GetFileNameWithoutExtension(_filename) + "-journal" + Path.GetExtension(_filename));
+            _journalFilename = FileHelper.GetTempFile(_filename, "-journal", false);
         }
 
         public void Initialize(Logger log, string password)

Utils/FileHelper.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+
+namespace LiteDB
+{
+    /// <summary>
+    /// A simple file helper tool with static methods
+    /// </summary>
+    internal class FileHelper
+    {
+        /// <summary>
+        /// Create a temp filename based on original filename - checks if file exists (if exists, append counter number)
+        /// </summary>
+        public static string GetTempFile(string filename, string sufix = "-temp", bool checkIfExists = true)
+        {
+            var count = 0;
+            var temp = Path.Combine(Path.GetDirectoryName(filename), 
+                Path.GetFileNameWithoutExtension(filename) + sufix + 
+                Path.GetExtension(filename));
+
+            while(checkIfExists && File.Exists(temp))
+            {
+                temp = Path.Combine(Path.GetDirectoryName(filename),
+                    Path.GetFileNameWithoutExtension(filename) + sufix +
+                    "-" + (++count) +
+                    Path.GetExtension(filename));
+            }
+
+            return temp;
+        }
+    }
+}