from github

Assets/ParrelSync/Editor/FileUtilities.cs

@@ -0,0 +1,31 @@
+using System.IO;
+using UnityEngine;
+
+namespace ParrelSync
+{
+    public class FileUtilities
+    {
+        public static bool IsFileLocked(string path)
+        {
+            FileInfo file = new FileInfo(path);
+            try
+            {
+                using (FileStream stream = file.Open(FileMode.Open, FileAccess.Read, FileShare.None))
+                {
+                    stream.Close();
+                }
+            }
+            catch (IOException)
+            {
+                //the file is unavailable because it is:
+                //still being written to
+                //or being processed by another thread
+                //or does not exist (has already been processed)
+                return true;
+            }
+
+            //file is not locked
+            return false;
+        }
+    }
+}