fixed IOException - directory not empty error when deleting cache folder

NetworkMiner/Program.cs

@@ -13,7 +13,8 @@
 using System.Reflection;
 using System.Diagnostics;
 using System.Globalization;
-
+using System.Threading.Tasks;
+
 namespace NetworkMiner {
     public static class Program {
 
@@ -22,7 +23,7 @@ public static class Program {
         /// <summary>
         /// The main entry point for the application.
         /// </summary>
-        static void Main(string[] args) {
+        static async Task Main(string[] args) {
             // first set up the logger
             SetupLogger("NetworkMiner");
 
@@ -49,7 +50,7 @@ static void Main(string[] args) {
 
 
             // remove the cache directory again
-            Directory.Delete(cacheDirectory, true);
+            await FileUtils.DeleteDirectory(cacheDirectory);
 
             // don't know why the application doesn't exit automatically after reaching the end of the main method...
             System.Environment.Exit(0);

SharedUtils/FileUtils.cs

@@ -0,0 +1,35 @@
+using System;
+using System.IO;
+using System.Threading.Tasks;
+
+namespace SharedUtils
+{
+    public static class FileUtils
+    {
+        public static async Task<bool> DeleteDirectory(string directoryPath, int maxRetries = 10, int millisecondsDelay = 30)
+        {
+            if (directoryPath == null)
+                throw new ArgumentNullException(directoryPath);
+            if (maxRetries < 1)
+                throw new ArgumentOutOfRangeException(nameof(maxRetries));
+            if (millisecondsDelay < 1)
+                throw new ArgumentOutOfRangeException(nameof(millisecondsDelay));
+
+            for (int i = 0; i < maxRetries; ++i) {
+                try {
+                    // try to delete the directory if it exists
+                    if (Directory.Exists(directoryPath))
+                        Directory.Delete(directoryPath, true);
+
+                    return true;
+                } catch (IOException) {  // System.IO.IOException: The directory is not empty
+                    await Task.Delay(millisecondsDelay);
+                } catch (UnauthorizedAccessException) {
+                    await Task.Delay(millisecondsDelay);
+                }
+            }
+
+            return false;
+        }
+    }
+}

SharedUtils/SharedUtils.csproj

@@ -52,6 +52,7 @@
     <Compile Include="Pcap\PcapParserFactory.cs" />
     <Compile Include="Pcap\PcapStreamReader.cs" />
     <Compile Include="Pcap\Tools.cs" />
+    <Compile Include="FileUtils.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
 </Project>