Fix file browser cancel/connetion issues (#528)

* clean bindingqueue after cancel

* fileborwser fixes

* code cleanup

* re-initialize filetree whenever filter is changed

* fix test issues

* address pr comments

src/Microsoft.SqlTools.ServiceLayer/FileBrowser/Contracts/FileBrowserCloseRequest.cs

@@ -42,4 +42,14 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser.Contracts
             RequestType<FileBrowserCloseParams, FileBrowserCloseResponse> Type =
                 RequestType<FileBrowserCloseParams, FileBrowserCloseResponse>.Create("filebrowser/close");
     }
+
+    /// <summary>
+    /// Notification for close completion
+    /// </summary>
+    public class FileBrowserClosedNotification
+    {
+        public static readonly
+            EventType<FileBrowserCloseResponse> Type =
+            EventType<FileBrowserCloseResponse>.Create("filebrowser/closecomplete");
+    }
 }

src/Microsoft.SqlTools.ServiceLayer/FileBrowser/FileBrowserBase.cs

@@ -30,7 +30,7 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
     public abstract class FileBrowserBase
     {
         private Enumerator enumerator = null;
-        protected SqlConnection sqlConnection = null;
+        protected ServerConnection connection = null;
 
         protected Enumerator Enumerator
         {
@@ -49,7 +49,7 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
         /// Returns the PathSeparator values of the Server.
         /// </summary>
         /// <returns>PathSeparator</returns>
-        internal static char GetPathSeparator(Enumerator enumerator, SqlConnection connection)
+        internal static char GetPathSeparator(Enumerator enumerator, ServerConnection connection)
         {
             var req = new Request();
             req.Urn = "Server";
@@ -78,7 +78,7 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
         /// <param name="enumerator"></param>
         /// <param name="connection"></param>
         /// <returns></returns>
-        internal static IEnumerable<FileInfo> EnumerateDrives(Enumerator enumerator, SqlConnection connection)
+        internal static IEnumerable<FileInfo> EnumerateDrives(Enumerator enumerator, ServerConnection connection)
         {
             // if not supplied, server name will be obtained from urn
             Request req = new Request();
@@ -145,7 +145,7 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
         /// <param name="connection"></param>
         /// <param name="path"></param>
         /// <returns></returns>
-        internal static IEnumerable<FileInfo> EnumerateFilesInFolder(Enumerator enumerator, SqlConnection connection, string path)
+        internal static IEnumerable<FileInfo> EnumerateFilesInFolder(Enumerator enumerator, ServerConnection connection, string path)
         {
             var request = new Request
             {

src/Microsoft.SqlTools.ServiceLayer/FileBrowser/FileBrowserOperation.cs

@@ -5,10 +5,10 @@
 
 using System;
 using System.Collections.Generic;
-using System.Data.SqlClient;
 using System.Globalization;
 using System.Text.RegularExpressions;
 using System.Threading;
+using Microsoft.SqlServer.Management.Common;
 using Microsoft.SqlTools.ServiceLayer.FileBrowser.Contracts;
 
 namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
@@ -30,21 +30,13 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
         /// <summary>
         /// Initializes a new instance of the <see cref="FileBrowser"/> class.
         /// </summary>
-        public FileBrowserOperation()
+        /// <param name="connection">The connection object</param>
+        /// <param name="fileFilters">The file extension filters</param>
+        public FileBrowserOperation(ServerConnection connection, string expandPath, string[] fileFilters = null)
         {
-            this.fileTree = new FileTree();
             this.cancelSource = new CancellationTokenSource();
             this.cancelToken = cancelSource.Token;
-        }
+            this.connection = connection;
-
-        /// <summary>
-        /// Initializes a new instance of the <see cref="FileBrowser"/> class.
-        /// </summary>
-        /// <param name="connectionInfo">The connection info</param>
-        /// <param name="fileFilters">The file extension filters</param>
-        public FileBrowserOperation(SqlConnection connectionInfo, string expandPath, string[] fileFilters = null): this()
-        {
-            this.sqlConnection = connectionInfo;
             this.Initialize(expandPath, fileFilters);
         }
 
@@ -76,14 +68,6 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
             }
         }
 
-        public SqlConnection SqlConnection
-        {
-            get
-            {
-                return this.sqlConnection;
-            }
-        }
-
         public bool IsCancellationRequested
         {
             get
@@ -100,6 +84,7 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
 
         public void Initialize(string expandPath, string[] fileFilters)
         {
+            this.fileTree = new FileTree();
             this.expandPath = expandPath;
             if (fileFilters == null)
             {
@@ -113,9 +98,9 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
 
         public void Dispose()
         {
-            if (this.sqlConnection != null)
+            if (this.connection != null)
             {
-                this.sqlConnection.Close();
+                this.connection.Disconnect();
             }
             this.cancelSource.Dispose();
         }
@@ -123,7 +108,7 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
         public void PopulateFileTree()
         {
             this.fileTreeCreated = false;
-            this.PathSeparator = GetPathSeparator(this.Enumerator, this.sqlConnection);
+            this.PathSeparator = GetPathSeparator(this.Enumerator, this.connection);
             PopulateDrives();
             ExpandSelectedNode(this.expandPath);
             this.fileTreeCreated = true;
@@ -191,7 +176,7 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
             bool first = true;
             if (!cancelToken.IsCancellationRequested)
             {
-                foreach (var fileInfo in EnumerateDrives(Enumerator, sqlConnection))
+                foreach (var fileInfo in EnumerateDrives(Enumerator, connection))
                 {
                     if (cancelToken.IsCancellationRequested)
                     {
@@ -221,7 +206,7 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
         public List<FileTreeNode> GetChildren(string filePath)
         { 
             List<FileTreeNode> children = new List<FileTreeNode>();
-            foreach (var file in EnumerateFilesInFolder(Enumerator, sqlConnection, filePath))
+            foreach (var file in EnumerateFilesInFolder(Enumerator, connection, filePath))
             {
                 bool isFile = !string.IsNullOrEmpty(file.fileName);
                 FileTreeNode treeNode = new FileTreeNode();

src/Microsoft.SqlTools.ServiceLayer/FileBrowser/FileBrowserService.cs

@@ -13,6 +13,7 @@ using Microsoft.SqlTools.ServiceLayer.FileBrowser.Contracts;
 using Microsoft.SqlTools.ServiceLayer.Hosting;
 using Microsoft.SqlTools.ServiceLayer.LanguageServices;
 using Microsoft.SqlTools.ServiceLayer.Utility;
+using Microsoft.SqlTools.Utility;
 
 namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
 {
@@ -28,8 +29,8 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
         private readonly ConcurrentDictionary<string, FileBrowserOperation> ownerToFileBrowserMap = new ConcurrentDictionary<string, FileBrowserOperation>();
         private readonly ConcurrentDictionary<string, ValidatePathsCallback> validatePathsCallbackMap = new ConcurrentDictionary<string, ValidatePathsCallback>();
         private ConnectionService connectionService;
-        private ConnectedBindingQueue expandNodeQueue = new ConnectedBindingQueue(needsMetadata: false);
+        private ConnectedBindingQueue fileBrowserQueue = new ConnectedBindingQueue(needsMetadata: false);
-        private static int DefaultExpandTimeout = 120000;
+        private static int DefaultTimeout = 120000;
         private string serviceName = "FileBrowser";
 
         /// <summary>
@@ -45,7 +46,7 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
                 if (connectionService == null)
                 {
                     connectionService = ConnectionService.Instance;
-                    connectionService.RegisterConnectedQueue(this.serviceName, this.expandNodeQueue);
+                    connectionService.RegisterConnectedQueue(this.serviceName, this.fileBrowserQueue);
                 }
                 return connectionService;
             }
@@ -94,8 +95,9 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
                     .ContinueWithOnFaulted(null);
                 await requestContext.SendResult(true);
             }
-            catch
+            catch (Exception ex)
             {
+                Logger.Write(LogLevel.Error, "Unexpected exception while handling file browser open request: " + ex.Message);
                 await requestContext.SendResult(false);
             }
         }
@@ -108,8 +110,9 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
                     .ContinueWithOnFaulted(null);
                 await requestContext.SendResult(true);
             }
-            catch
+            catch (Exception ex)
             {
+                Logger.Write(LogLevel.Error, "Unexpected exception while handling file browser expand request: " + ex.Message);
                 await requestContext.SendResult(false);
             }
         }
@@ -122,8 +125,9 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
                     .ContinueWithOnFaulted(null);
                 await requestContext.SendResult(true);
             }
-            catch
+            catch (Exception ex)
             {
+                Logger.Write(LogLevel.Error, "Unexpected exception while handling file browser validate request: " + ex.Message);
                 await requestContext.SendResult(false);
             }
         }
@@ -132,90 +136,139 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
             FileBrowserCloseParams fileBrowserParams,
             RequestContext<FileBrowserCloseResponse> requestContext)
         {
-            FileBrowserCloseResponse response = new FileBrowserCloseResponse();
+            try
-            FileBrowserOperation removedOperation;
-            response.Succeeded = ownerToFileBrowserMap.TryRemove(fileBrowserParams.OwnerUri, out removedOperation);
-
-            if (removedOperation != null && this.expandNodeQueue != null)
             {
-                bool hasPendingQueueItems = this.expandNodeQueue.HasPendingQueueItems;
+                var task = Task.Run(() => RunFileBrowserCloseTask(fileBrowserParams, requestContext))
-                if (removedOperation.FileTreeCreated && !hasPendingQueueItems)
+                    .ContinueWithOnFaulted(null);
-                {
+                await requestContext.SendResult(new FileBrowserCloseResponse() { Succeeded = true });
-                    removedOperation.Dispose();
+            }
-                    this.expandNodeQueue.CloseConnections(removedOperation.SqlConnection.DataSource, removedOperation.SqlConnection.Database, DefaultExpandTimeout);
+            catch (Exception ex)
-                }
+            {
-                else if (!removedOperation.FileTreeCreated)
+                Logger.Write(LogLevel.Error, "Unexpected exception while handling file browser close request: " + ex.Message);
-                {
+                await requestContext.SendResult(new FileBrowserCloseResponse() { Message = ex.Message });
-                    removedOperation.Cancel();
-                }
-                else if (hasPendingQueueItems)
-                { 
-                    this.expandNodeQueue.StopQueueProcessor(DefaultExpandTimeout);
-                }
             }
-
-            await requestContext.SendResult(response);
         }
 
         #endregion
 
         public void Dispose()
         {
-            this.expandNodeQueue.Dispose();
+            this.fileBrowserQueue.Dispose();
+        }
+
+        internal async Task RunFileBrowserCloseTask(FileBrowserCloseParams fileBrowserParams, RequestContext<FileBrowserCloseResponse> requestContext)
+        {
+            FileBrowserCloseResponse result = new FileBrowserCloseResponse();
+            try
+            {
+                FileBrowserOperation operation = null;
+                ConnectionInfo connInfo;
+                ownerToFileBrowserMap.TryGetValue(fileBrowserParams.OwnerUri, out operation);
+                this.ConnectionServiceInstance.TryFindConnection(fileBrowserParams.OwnerUri, out connInfo);
+
+                if (operation != null && connInfo != null)
+                {
+                    if (!operation.FileTreeCreated)
+                    {
+                        operation.Cancel();
+                    }
+
+                    // Clear queued items
+                    this.fileBrowserQueue.ClearQueuedItems();
+
+                    // Queue operation to clean up resources
+                    QueueItem queueItem = fileBrowserQueue.QueueBindingOperation(
+                        key: fileBrowserQueue.AddConnectionContext(connInfo, this.serviceName),
+                        bindingTimeout: DefaultTimeout,
+                        waitForLockTimeout: DefaultTimeout,
+                        bindOperation: (bindingContext, cancelToken) =>
+                        {
+                            FileBrowserOperation removedOperation = null;
+                            ownerToFileBrowserMap.TryRemove(fileBrowserParams.OwnerUri, out removedOperation);
+                            if (removedOperation != null)
+                            {
+                                removedOperation.Dispose();
+                            }
+                            result.Succeeded = true;
+                            return result;
+                        });
+
+                    queueItem.ItemProcessed.WaitOne();
+                    if (queueItem.GetResultAsT<FileBrowserCloseResponse>() != null)
+                    {
+                        result = queueItem.GetResultAsT<FileBrowserCloseResponse>();
+                    }
+
+                    this.fileBrowserQueue.CloseConnections(connInfo.ConnectionDetails.ServerName, connInfo.ConnectionDetails.DatabaseName, DefaultTimeout);
+                }
+            }
+            catch (Exception ex)
+            {
+                Logger.Write(LogLevel.Error, "Unexpected exception while closing file browser: " + ex.Message);
+                result.Message = ex.Message;
+            }
+
+            await requestContext.SendEvent(FileBrowserClosedNotification.Type, result);
         }
 
         internal async Task RunFileBrowserOpenTask(FileBrowserOpenParams fileBrowserParams, RequestContext<bool> requestContext)
         {
             FileBrowserOpenedParams result = new FileBrowserOpenedParams();
-            SqlConnection conn = null;
             FileBrowserOperation browser = null;
             bool isCancelRequested = false;
 
-            if (this.expandNodeQueue.IsCancelRequested)
-            {
-                this.expandNodeQueue.StartQueueProcessor();
-            }
-
             try
             {
-                if (!fileBrowserParams.ChangeFilter)
+                ConnectionInfo connInfo;
+                this.ConnectionServiceInstance.TryFindConnection(fileBrowserParams.OwnerUri, out connInfo);
+                if (connInfo != null)
                 {
-                    ConnectionInfo connInfo;
+                    QueueItem queueItem = fileBrowserQueue.QueueBindingOperation(
-                    this.ConnectionServiceInstance.TryFindConnection(fileBrowserParams.OwnerUri, out connInfo);
+                        key: fileBrowserQueue.AddConnectionContext(connInfo, this.serviceName),
-                    if (connInfo != null)
+                        bindingTimeout: DefaultTimeout,
-                    {
+                        waitForLockTimeout: DefaultTimeout,
-                        // Open new connection for each Open request
+                        bindOperation: (bindingContext, cancelToken) =>
-                        conn = ConnectionService.OpenSqlConnection(connInfo, this.serviceName);
+                        {
-                        browser = new FileBrowserOperation(conn, fileBrowserParams.ExpandPath, fileBrowserParams.FileFilters);
+                            if (!fileBrowserParams.ChangeFilter)
-                    }
+                            {
-                }
+                                browser = new FileBrowserOperation(bindingContext.ServerConnection, fileBrowserParams.ExpandPath, fileBrowserParams.FileFilters);
-                else
+                            }
-                {
+                            else
-                    ownerToFileBrowserMap.TryGetValue(fileBrowserParams.OwnerUri, out browser);
+                            {
-                    if (browser != null)
+                                ownerToFileBrowserMap.TryGetValue(fileBrowserParams.OwnerUri, out browser);
-                    {
+                                if (browser != null)
-                        browser.Initialize(fileBrowserParams.ExpandPath, fileBrowserParams.FileFilters);
+                                {
-                    }
+                                    browser.Initialize(fileBrowserParams.ExpandPath, fileBrowserParams.FileFilters);
-                }
+                                }
+                            }
 
-                if (browser != null)
+                            if (browser != null)
-                {
+                            {
-                    ownerToFileBrowserMap.AddOrUpdate(fileBrowserParams.OwnerUri, browser, (key, value) => browser);
+                                ownerToFileBrowserMap.AddOrUpdate(fileBrowserParams.OwnerUri, browser, (key, value) => browser);
 
-                    // Create file browser tree
+                                // Create file browser tree
-                    browser.PopulateFileTree();
+                                browser.PopulateFileTree();
 
-                    // Check if cancel was requested
+                                if (browser.IsCancellationRequested)
-                    if (browser.IsCancellationRequested)
+                                {
+                                    isCancelRequested = true;
+                                }
+                                else
+                                {
+                                    result.OwnerUri = fileBrowserParams.OwnerUri;
+                                    result.FileTree = browser.FileTree;
+                                    result.Succeeded = true;
+                                }
+                            }
+
+                            return result;
+                        });
+
+                    queueItem.ItemProcessed.WaitOne();
+
+                    if (queueItem.GetResultAsT<FileBrowserOpenedParams>() != null)
                     {
-                        browser.Dispose();
+                        result = queueItem.GetResultAsT<FileBrowserOpenedParams>();
-                        isCancelRequested = true;
-                    }
-                    else
-                    {
-                        result.OwnerUri = fileBrowserParams.OwnerUri;
-                        result.FileTree = browser.FileTree;
-                        result.Succeeded = true;
                     }
                 }
             }
@@ -235,32 +288,29 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
             FileBrowserExpandedParams result = new FileBrowserExpandedParams();
             try
             {
-                FileBrowserOperation operation;
+                FileBrowserOperation operation = null;
                 ConnectionInfo connInfo;
-                result.Succeeded = ownerToFileBrowserMap.TryGetValue(fileBrowserParams.OwnerUri, out operation);
+                ownerToFileBrowserMap.TryGetValue(fileBrowserParams.OwnerUri, out operation);
                 this.ConnectionServiceInstance.TryFindConnection(fileBrowserParams.OwnerUri, out connInfo);
 
-                if (result.Succeeded && operation != null && connInfo != null)
+                if (operation != null && connInfo != null)
                 {
-                    QueueItem queueItem = expandNodeQueue.QueueBindingOperation(
+                    QueueItem queueItem = fileBrowserQueue.QueueBindingOperation(
-                        key: expandNodeQueue.AddConnectionContext(connInfo, this.serviceName),
+                        key: fileBrowserQueue.AddConnectionContext(connInfo, this.serviceName),
-                        bindingTimeout: DefaultExpandTimeout,
+                        bindingTimeout: DefaultTimeout,
-                        waitForLockTimeout: DefaultExpandTimeout,
+                        waitForLockTimeout: DefaultTimeout,
                         bindOperation: (bindingContext, cancelToken) =>
                         {
                             result.ExpandPath = fileBrowserParams.ExpandPath;
                             result.Children = operation.GetChildren(fileBrowserParams.ExpandPath).ToArray();
                             result.OwnerUri = fileBrowserParams.OwnerUri;
+                            result.Succeeded = true;
                             return result;
                         });
 
                     queueItem.ItemProcessed.WaitOne();
 
-                    if (this.expandNodeQueue.IsCancelRequested)
+                    if (queueItem.GetResultAsT<FileBrowserExpandedParams>() != null)
-                    {
-                        this.expandNodeQueue.CloseConnections(operation.SqlConnection.DataSource, operation.SqlConnection.Database, DefaultExpandTimeout);
-                    }
-                    else if (queueItem.GetResultAsT<FileBrowserExpandedParams>() != null)
                     {
                         result = queueItem.GetResultAsT<FileBrowserExpandedParams>();
                     }
@@ -268,7 +318,6 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
             }
             catch (Exception ex)
             {
-                result.Succeeded = false;
                 result.Message = ex.Message;
             }
 
@@ -282,22 +331,36 @@ namespace Microsoft.SqlTools.ServiceLayer.FileBrowser
             try
             {
                 ValidatePathsCallback callback;
+                ConnectionInfo connInfo;
+                this.ConnectionServiceInstance.TryFindConnection(fileBrowserParams.OwnerUri, out connInfo);
                 if (validatePathsCallbackMap.TryGetValue(fileBrowserParams.ServiceType, out callback)
                     && callback != null
+                    && connInfo != null
                     && fileBrowserParams.SelectedFiles != null
                     && fileBrowserParams.SelectedFiles.Length > 0)
                 {
-                    string errorMessage;
+                    QueueItem queueItem = fileBrowserQueue.QueueBindingOperation(
-                    result.Succeeded = callback(new FileBrowserValidateEventArgs
+                        key: fileBrowserQueue.AddConnectionContext(connInfo, this.serviceName),
-                    {
+                        bindingTimeout: DefaultTimeout,
-                        ServiceType = fileBrowserParams.ServiceType,
+                        waitForLockTimeout: DefaultTimeout,
-                        OwnerUri = fileBrowserParams.OwnerUri,
+                        bindOperation: (bindingContext, cancelToken) =>
-                        FilePaths = fileBrowserParams.SelectedFiles
+                        {
-                    }, out errorMessage);
+                            string errorMessage;
+                            result.Succeeded = callback(new FileBrowserValidateEventArgs
+                            {
+                                ServiceType = fileBrowserParams.ServiceType,
+                                OwnerUri = fileBrowserParams.OwnerUri,
+                                FilePaths = fileBrowserParams.SelectedFiles
+                            }, out errorMessage);
+                            result.Message = errorMessage;
+                            return result;
+                        });
 
-                    if (!string.IsNullOrEmpty(errorMessage))
+                    queueItem.ItemProcessed.WaitOne();
+
+                    if (queueItem.GetResultAsT<FileBrowserValidatedParams>() != null)
                     {
-                        result.Message = errorMessage;
+                        result = queueItem.GetResultAsT<FileBrowserValidatedParams>();
                     }
                 }
                 else

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/BindingQueue.cs

@@ -388,6 +388,20 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
             }
         }
 
+        /// <summary>
+        /// Clear queued items
+        /// </summary>
+        public void ClearQueuedItems()
+        {
+            lock (this.bindingQueueLock)
+            {
+                if (this.bindingQueue.Count > 0)
+                {
+                    this.bindingQueue.Clear();
+                }
+            }
+        }
+
         public void Dispose()
         {
             if (this.processQueueCancelToken != null)

test/Microsoft.SqlTools.ServiceLayer.IntegrationTests/FileBrowser/FileBrowserServiceTests.cs

@@ -91,9 +91,7 @@ namespace Microsoft.SqlTools.ServiceLayer.IntegrationTests.FileBrowser
             };
 
             await service.HandleFileBrowserCloseRequest(inputParams, requestContext.Object);
-
+            requestContext.Verify(x => x.SendResult(It.Is<FileBrowserCloseResponse>(p => p.Succeeded == true)));
-            // Result should return false since it's trying to close a filebrowser that was never opened
-            requestContext.Verify(x => x.SendResult(It.Is<FileBrowserCloseResponse>(p => p.Succeeded == false)));
         }
 
         #endregion

test/Microsoft.SqlTools.ServiceLayer.UnitTests/FileBrowser/FileBrowserTests.cs

@@ -28,7 +28,7 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.FileBrowser
         [Fact]
         public void FilterFilesTest()
         {
-            FileBrowserOperation operation = new FileBrowserOperation();
+            FileBrowserOperation operation = new FileBrowserOperation(null, "", null);
             string[] supportedFilePaths = new string[] {"te\\s/t1.txt", "te!s.t2.bak" };
             string[] unsupportedFilePaths = new string[] { "te.s*/t3.jpg", "t_est4.trn" };
             string[] filters = new string[] { "*.txt", "*.bak"};
@@ -47,7 +47,7 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.FileBrowser
         [Fact]
         public void ExpandNodeShouldThrowExceptionForInvalidPath()
         {
-            FileBrowserOperation operation = new FileBrowserOperation();
+            FileBrowserOperation operation = new FileBrowserOperation(null, "", null);
             Exception exception = null;
 
             try