New logic for connection to a xapi database and some connection tidy up:

- Removed event that had no subscribers.
- The xml docs are more useful on the properties and not their supporting private fields.
- Stop silencing cache errors as they may reveal other issues.
- Adding server to history was called twice.
- Connection null checks and refactoring of ConnectionExists exceptions.
- Added some logging.

Signed-off-by: Konstantina Chremmou <Konstantina.Chremmou@cloud.com>

XenAdmin/Controls/Wlb/WlbOptimizePool.cs

@@ -39,6 +39,7 @@ using XenAPI;
 using XenAdmin.Actions;
 using XenAdmin.Actions.Wlb;
 using XenAdmin.Commands;
+using XenAdmin.Network;
 
 
 namespace XenAdmin.Controls.Wlb
@@ -526,7 +527,7 @@ namespace XenAdmin.Controls.Wlb
         {
             Program.AssertOnEventThread();
 
-            if(_xenObject == null)
+            if (_xenObject == null || _xenObject.Connection is XenConnection conn && conn.IsSimulatedConnection)
                 return;
 
             if (Helpers.WlbEnabled(_xenObject.Connection))

XenAdmin/Dialogs/AddServerDialog.cs

@@ -29,6 +29,7 @@
  */
 
 using System;
+using System.IO;
 using System.Linq;
 using XenAdmin.Core;
 using XenAdmin.Network;
@@ -146,19 +147,12 @@ namespace XenAdmin.Dialogs
                 conn = connection;
 
             foreach (var server in servers)
-            {
+                ConnectToServer(conn, server, username, password);
-                StringUtility.ParseHostnamePort(server, out var hostname, out var port);
-
-                if (port == 0)
-                    port = ConnectionsManager.DEFAULT_XEN_PORT;
-
-                ConnectToServer(conn, hostname, port, username, password);
-            }
 
             Close();
         }
 
-        private void ConnectToServer(IXenConnection conn, string hostname, int port, string username, string password)
+        private void ConnectToServer(IXenConnection conn, string server, string username, string password)
         {
             if (conn == null)
             {
@@ -170,14 +164,27 @@ namespace XenAdmin.Dialogs
                 conn.EndConnect(); // in case we're already connected
             }
 
-            conn.Hostname = hostname;
-            conn.Port = port;
             conn.Username = username;
             conn.Password = password;
             conn.ExpectPasswordIsCorrect = false;
 
-            if (!_changedPass)
+            if (File.Exists(server))
+            {
+                conn.Hostname = server;
+                conn.Port = ConnectionsManager.DEFAULT_XEN_PORT;
+                XenConnectionUI.ConnectToXapiDatabase(conn, this);
+            }
+            else if (!_changedPass)
+            {
+                StringUtility.ParseHostnamePort(server, out var hostname, out var port);
+
+                if (port == 0)
+                    port = ConnectionsManager.DEFAULT_XEN_PORT;
+                
+                conn.Hostname = hostname;
+                conn.Port = port;
                 XenConnectionUI.BeginConnect(conn, true, Owner, false);
+            }
         }
 
         private void conn_CachePopulated(IXenConnection conn)

XenAdmin/Dialogs/RoleElevationDialog.cs

@@ -62,7 +62,7 @@ namespace XenAdmin.Dialogs
         {
             InitializeComponent();
             UserDetails ud = session.CurrentUserDetails;
-            labelCurrentUserValue.Text = ud.UserDisplayName ?? ud.UserName ?? Messages.UNKNOWN_AD_USER;
+            labelCurrentUserValue.Text = ud?.UserDisplayName ?? ud?.UserName ?? Messages.UNKNOWN_AD_USER;
             labelCurrentRoleValue.Text = Role.FriendlyCSVRoleList(session.Roles);
             authorizedRoles.Sort((r1, r2) => r2.CompareTo(r1));
             labelRequiredRoleValue.Text = Role.FriendlyCSVRoleList(authorizedRoles);

XenAdmin/Network/XenConnectionUI.cs

@@ -44,6 +44,18 @@ namespace XenAdmin.Network
     {
         public static Dictionary<IXenConnection, ConnectingToServerDialog> connectionDialogs = new Dictionary<IXenConnection, ConnectingToServerDialog>();
 
+        public static void ConnectToXapiDatabase(IXenConnection conn, Form owner)
+        {
+            try
+            {
+                ((XenConnection)conn).LoadFromDatabaseFile(conn.Hostname);
+            }
+            catch (ConnectionExists e)
+            {
+                ShowConnectingDialogError(owner, conn, e);
+            }
+        }
+
         /// <summary>
         /// Start connecting to a server
         /// </summary>
@@ -254,7 +266,7 @@ namespace XenAdmin.Network
 
                 if (!Program.RunInAutomatedTestMode)
                 {
-                    using (var dlg = new InformationDialog(c.GetDialogMessage(connection)))
+                    using (var dlg = new InformationDialog(c.GetDialogMessage()))
                         dlg.ShowDialog(owner);
                 }
             }

XenModel/Db.cs

@@ -0,0 +1,181 @@
+/* Copyright (c) Cloud Software Group, Inc. 
+* 
+* Redistribution and use in source and binary forms, 
+* with or without modification, are permitted provided 
+* that the following conditions are met: 
+* 
+* *   Redistributions of source code must retain the above 
+*     copyright notice, this list of conditions and the 
+*     following disclaimer. 
+* *   Redistributions in binary form must reproduce the above 
+*     copyright notice, this list of conditions and the 
+*     following disclaimer in the documentation and/or other 
+*     materials provided with the distribution. 
+* 
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
+* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
+* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
+* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
+* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
+* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
+* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 
+* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
+* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
+* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+* SUCH DAMAGE.
+*/
+
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Xml;
+using XenAdmin.Core;
+using XenAPI;
+
+namespace XenAdmin
+{
+    public class Db
+    {
+        private static readonly log4net.ILog _log = log4net.LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+        public Db(XmlDocument document)
+        {
+            XmlNode dbNode = document.ChildNodes.Cast<XmlNode>().FirstOrDefault(node => node.Name == "database") ??
+                             throw new ArgumentException("Couldn't find database tag in state db");
+
+            foreach (XmlNode n in dbNode.ChildNodes)
+            {
+                if (n.Name != "table")
+                    continue;
+
+                try
+                {
+                    Tables.Add(new DbTable(n));
+                }
+                catch (Exception e)
+                {
+                    _log.Error(e);
+                }
+            }
+        }
+
+        public List<DbTable> Tables { get; } = new List<DbTable>();
+    }
+
+
+    /// <summary>
+    /// Corresponds to an API class type. Its Rows are the class instances (API objects)
+    /// </summary>
+    public class DbTable
+    {
+        private static readonly log4net.ILog _log = log4net.LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+        private static readonly Type[] AssemblyTypes = Assembly.GetExecutingAssembly().GetTypes();
+
+        public DbTable(XmlNode tableNode)
+        {
+            var name = tableNode.Attributes?["name"].Value;
+
+            ApiClassType = AssemblyTypes
+                .Where(t => t.Namespace == nameof(XenAPI))
+                .FirstOrDefault(t => string.Equals(t.Name, name, StringComparison.CurrentCultureIgnoreCase));
+
+            foreach (XmlNode n in tableNode.ChildNodes)
+            {
+                if (n.Name != "row")
+                    continue;
+
+                try
+                {
+                    Rows.Add(new Row(ApiClassType, n));
+                }
+                catch (Exception e)
+                {
+                    _log.Error(e);
+                }
+            }
+        }
+
+        public Type ApiClassType { get; }
+
+        public List<Row> Rows { get; } = new List<Row>();
+    }
+
+
+    /// <summary>
+    /// Corresponds to an API object
+    /// </summary>
+    public class Row
+    {
+        private readonly XmlNode _rowNode;
+
+        public Row(Type apiClassType, XmlNode rowNode)
+        {
+            _rowNode = rowNode;
+
+            HashTable = ConvertToHashtable(out var opaqueRef);
+            XenObject = ConvertToXenObject(apiClassType);
+
+            if (XenObject != null)
+                XenObject.opaque_ref = opaqueRef;
+
+            ObjectChange = new ObjectChange(apiClassType, opaqueRef, XenObject);
+        }
+
+        public Hashtable HashTable { get; }
+
+        public IXenObject XenObject { get; }
+
+        public ObjectChange ObjectChange { get; }
+
+        private Hashtable ConvertToHashtable(out string opaqueRef)
+        {
+            opaqueRef = "OpaqueRef:NULL";
+
+            if (_rowNode.Attributes == null)
+                return null;
+
+            var hashtable = new Hashtable();
+
+            foreach (XmlAttribute attr in _rowNode.Attributes)
+            {
+                if (attr.Name.StartsWith("__"))
+                    continue;
+
+                if (attr.Name == "_ref")
+                {
+                    opaqueRef = attr.Value;
+                    continue;
+                }
+
+                var key = attr.Name.Replace("__", "_");
+
+                hashtable[key] = EscapeXapiChars(attr.Value);
+            }
+
+            return hashtable;
+        }
+
+        private IXenObject ConvertToXenObject(Type apiClassType)
+        {
+            return apiClassType?.GetConstructor(new[] { typeof(Hashtable) })?.Invoke(new object[] { HashTable }) as IXenObject;
+        }
+
+        private string EscapeXapiChars(string input)
+        {
+            input = input.Replace("%.", " ");
+            input = input.Replace("%_", "  ");
+            input = input.Replace("%n", "\n");
+            input = input.Replace("%r", "\r");
+            input = input.Replace("%t", "\t");
+            input = input.Replace("%%", "%");
+            return input;
+        }
+    }
+}

XenModel/Network/IXenConnection.cs

@@ -62,9 +62,7 @@ namespace XenAdmin.Network
         Session DuplicateSession(int timeout);
         void EndConnect(bool resetState = true, bool exiting = false);
         void Interrupt();
-        Session Connect(string user, string password);
         List<string> PoolMembers { get; set; }
-        void LoadCache(Session session);
         bool SuppressErrors { get; set; }
         bool PreventResettingPasswordPrompt { get;set; }
         bool CoordinatorMayChange { get; set; }
@@ -83,7 +81,6 @@ namespace XenAdmin.Network
         void WaitFor(Func<bool> predicate, Func<bool> cancelling);
         TimeSpan ServerTimeOffset { get; set; }
         Session Session { get; }
-        event EventHandler<EventArgs> TimeSkewUpdated;
         string UriScheme { get; }
         event EventHandler<EventArgs> XenObjectsUpdated;
         NetworkCredential NetworkCredential { get; set; }

XenModel/Network/XenConnection.cs

@@ -39,7 +39,9 @@ using XenAdmin.Core;
 using XenAPI;
 using XenCenterLib;
 using System.Diagnostics;
+using System.IO;
 using System.Linq;
+using System.Xml;
 using System.Xml.Serialization;
 
 
@@ -71,13 +73,20 @@ namespace XenAdmin.Network
         /// </summary>
         public bool fromDialog = false;
 
+        private volatile bool _expectedDisruption;
+        private volatile bool _suppressErrors;
+        private volatile bool _preventResettingPasswordPrompt;
+        private volatile bool _coordinatorMayChange;
+
         /// <summary>
         /// Whether we're expecting network disruption, say because we're reconfiguring the network at this time.  In that case, we ignore
         /// keepalive failures, and expect task polling to be disrupted.
         /// </summary>
-        private volatile bool _expectedDisruption = false;
+        public bool ExpectDisruption
-
+        {
-        public bool ExpectDisruption { get { return _expectedDisruption; } set { _expectedDisruption = value; } }
+            get => _expectedDisruption;
+            set => _expectedDisruption = value;
+        }
 
         /// <summary>
         /// If we are 'expecting' this connection's Password property to contain the correct password
@@ -88,16 +97,12 @@ namespace XenAdmin.Network
         /// <summary>
         /// Used by the patch wizard, suppress any errors coming from reconnect attempts
         /// </summary>
-        private volatile bool _suppressErrors;
         public bool SuppressErrors
         {
             get => _suppressErrors;
             set => _suppressErrors = value;
         }
 
-
-        private volatile bool _preventResettingPasswordPrompt;
-
         /// <summary>
         /// The password prompting function (<see cref="_promptForNewPassword"/>) is set to null when the connection is closed.
         /// Set this value to true in order to prevent that from happening.
@@ -112,9 +117,11 @@ namespace XenAdmin.Network
         /// <summary>
         /// Indicates whether we are expecting the pool coordinator to change soon (e.g. when explicitly designating a new coordinator).
         /// </summary>
-        private volatile bool _coordinatorMayChange = false;
+        public bool CoordinatorMayChange
-
+        {
-        public bool CoordinatorMayChange { get { return _coordinatorMayChange; } set { _coordinatorMayChange = value; } }
+            get => _coordinatorMayChange;
+            set => _coordinatorMayChange = value;
+        }
 
         /// <summary>
         /// Set when we detect that Event.next() has become blocked and we need to reset the connection. See CA-33145.
@@ -132,11 +139,15 @@ namespace XenAdmin.Network
         private string CoordinatorIPAddress = "";
 
         /// <summary>
-        /// The lock that must be taken around connectTask and monitor.
+        /// The lock that must be taken around connectTask and heartbeat.
         /// </summary>
         private readonly object connectTaskLock = new object();
         private ConnectTask connectTask = null;
-        private Heartbeat heartbeat = null;
+
+        /// <summary>
+        /// This is the metrics monitor. Has to be accessed within the connectTaskLock.
+        /// </summary>
+        private Heartbeat heartbeat;
 
         /// <summary>
         /// Whether we are trying to automatically connect to the new coordinator. Set in HandleConnectionLost.
@@ -166,7 +177,7 @@ namespace XenAdmin.Network
 
         private DateTime m_startTime = DateTime.MinValue;
         private int m_lastDebug;
-        private TimeSpan ServerTimeOffset_ = TimeSpan.Zero;
+        private TimeSpan _serverTimeOffset = TimeSpan.Zero;
         private object ServerTimeOffsetLock = new object();
         /// <summary>
         /// The offset between the clock at the client and the clock at the server.  server time + ServerTimeOffset = client time.
@@ -179,15 +190,14 @@ namespace XenAdmin.Network
             {
                 lock (ServerTimeOffsetLock)
                 {
-                    return ServerTimeOffset_;
+                    return _serverTimeOffset;
                 }
             }
-
             set
             {
                 lock (ServerTimeOffsetLock)
                 {
-                    TimeSpan diff = ServerTimeOffset_ - value;
+                    TimeSpan diff = _serverTimeOffset - value;
 
                     if (diff.TotalSeconds < -1 || 1 < diff.TotalSeconds)
                     {
@@ -212,11 +222,8 @@ namespace XenAdmin.Network
                         }
                     }
 
-                    ServerTimeOffset_ = value;
+                    _serverTimeOffset = value;
                 }
-
-                if (TimeSkewUpdated != null)
-                    TimeSkewUpdated(this, EventArgs.Empty);
             }
         }
 
@@ -250,8 +257,7 @@ namespace XenAdmin.Network
         /// <summary>
         /// The cache of XenAPI objects for this connection.
         /// </summary>
-        private readonly ICache _cache = new Cache();
+        public ICache Cache { get; } = new Cache();
-        public ICache Cache { get { return _cache; } }
 
         private readonly LockFreeQueue<ObjectChange> eventQueue = new LockFreeQueue<ObjectChange>();
         private readonly System.Threading.Timer cacheUpdateTimer;
@@ -259,12 +265,20 @@ namespace XenAdmin.Network
         /// <summary>
         /// Whether the cache for this connection has been populated.
         /// </summary>
-        private bool cacheIsPopulated = false;
         public bool CacheIsPopulated
         {
-            get { return cacheIsPopulated; }
+            get => _cacheIsPopulated;
+            private set
+            {
+                _cacheIsPopulated = value;
+
+                if (_cacheIsPopulated)
+                    CachePopulated?.Invoke(this);
+            }
         }
 
+        private bool _cacheIsPopulated;
+
         private bool cacheUpdaterRunning = false;
         private bool updatesWaiting = false;
 
@@ -280,56 +294,7 @@ namespace XenAdmin.Network
             cacheUpdateTimer = new Timer(cacheUpdater);
         }
 
-        /// <summary>
+        #region Events
-        /// For use by unit tests only.
-        /// </summary>
-        /// <param name="user"></param>
-        /// <param name="password"></param>
-        /// <returns></returns>
-        public Session Connect(string user, string password)
-        {
-            heartbeat = new Heartbeat(this, XenAdminConfigManager.Provider.ConnectionTimeout);
-            Session session = new Session(Session.STANDARD_TIMEOUT, this, Hostname, Port);
-
-            try
-            {
-                session.login_with_password(user, password, Helper.APIVersionString(API_Version.LATEST), Session.UserAgent);
-
-                // this is required so connection.IsConnected returns true in the unit tests.
-                connectTask = new ConnectTask("test", 0);
-                connectTask.Connected = true;
-                connectTask.Session = session;
-
-                return session;
-            }
-            catch (Exception)
-            {
-                return null;
-            }
-
-        }
-
-        /// <summary>
-        /// Used by unit tests only.
-        /// </summary>
-        /// <param name="session">The session.</param>
-        public void LoadCache(Session session)
-        {
-            this.Cache.Clear();
-
-            cacheIsPopulated = false;
-
-            string token = "";
-            XenObjectDownloader.GetAllObjects(session, eventQueue, () => false, ref token);
-            List<ObjectChange> events = new List<ObjectChange>();
-
-            while (eventQueue.NotEmpty)
-                events.Add(eventQueue.Dequeue());
-
-            this.Cache.UpdateFrom(this, events);
-            cacheIsPopulated = true;
-
-        }
 
         /// <summary>
         /// Fired just before the cache is cleared (i.e. the cache is still populated).
@@ -351,8 +316,48 @@ namespace XenAdmin.Network
         /// </summary>
         public event EventHandler<EventArgs> XenObjectsUpdated;
 
+        #endregion
+
+        public void LoadFromDatabaseFile(string databaseFile)
+        {
+            IsSimulatedConnection = true;
+
+            var foundConn = ConnectionsManager.XenConnections.Cast<XenConnection>().FirstOrDefault(c =>
+                    c.Hostname == databaseFile && c.CoordinatorIPAddress == CoordinatorIPAddress);
+            if (foundConn != null && foundConn.IsConnected)
+                throw new ConnectionExists(this);
+
+            var document = new XmlDocument();
+            using (var sr = new StreamReader(databaseFile))
+                document.LoadXml(sr.ReadToEnd());
+
+            var db = new Db(document);
+            var events = db.Tables.SelectMany(t => t.Rows).Select(r => r.ObjectChange).ToList();
+
+            var session = new Session(Session.STANDARD_TIMEOUT, this, Path.GetFileName(Hostname), Port);
+            connectTask = new ConnectTask(Hostname, Port) { Connected = true, Session = session };
+
+            OnBeforeMajorChange(false);
+            Cache.Clear();
+            CacheIsPopulated = false;
+            OnAfterMajorChange(false);
+
+            OnBeforeMajorChange(false);
+            Cache.UpdateFrom(this, events);
+            OnAfterMajorChange(false);
+            CacheIsPopulated = true;
+
+            var pool = Cache.Pools[0];
+            CoordinatorIPAddress = Cache.Hosts.FirstOrDefault(h => h.opaque_ref == pool.master)?.address;
+            
+            HandleSuccessfulConnection(connectTask, pool);
+            MarkConnectActionComplete();
+            OnXenObjectsUpdated();
+        }
+
         public NetworkCredential NetworkCredential { get; set; }
-        public event EventHandler<EventArgs> TimeSkewUpdated;
+
+        public bool IsSimulatedConnection { get; private set; }
 
         public bool IsConnected
         {
@@ -608,6 +613,8 @@ namespace XenAdmin.Network
 
             lock (connectTaskLock)
             {
+                //if connectTask != null a connection is already in progress
+
                 if (connectTask == null)
                 {
                     ClearEventQueue();
@@ -615,17 +622,16 @@ namespace XenAdmin.Network
                     Cache.Clear();
                     OnAfterMajorChange(false);
                     connectTask = new ConnectTask(Hostname, Port);
-                    StopMonitor();
+
+                    heartbeat?.Stop();
+                    heartbeat = null;
                     heartbeat = new Heartbeat(this, XenAdminConfigManager.Provider.ConnectionTimeout);
+
                     Thread t = new Thread(ConnectWorkerThread);
                     t.Name = "Connection to " + Hostname;
                     t.IsBackground = true;
                     t.Start(connectTask);
                 }
-                else
-                {
-                    // a connection is already in progress
-                }
             }
         }
 
@@ -745,7 +751,9 @@ namespace XenAdmin.Network
 
             lock (connectTaskLock)
             {
-                StopMonitor();
+                heartbeat?.Stop();
+                heartbeat = null;
+
                 if (task != null)
                 {
                     task.Cancelled = true;
@@ -759,6 +767,7 @@ namespace XenAdmin.Network
             }
 
             MarkConnectActionComplete();
+            log.Info($"Connection to {Hostname} is ended.");
 
             // Save list of addresses of current hosts in pool
             List<string> members = new List<string>();
@@ -861,18 +870,6 @@ namespace XenAdmin.Network
             Cache.Clear();
         }
 
-        private void OnCachePopulated()
-        {
-            lock (connectTaskLock)
-            {
-                if (heartbeat != null)
-                    heartbeat.Start();
-            }
-
-            CachePopulated?.Invoke(this);
-            MarkConnectActionComplete();
-        }
-
         private string GetReason(Exception error)
         {
             if (error is ArgumentException)
@@ -930,8 +927,16 @@ namespace XenAdmin.Network
             }
         }
 
-        private void HandleSuccessfulConnection(string taskHostname, int task_port)
+        private void HandleSuccessfulConnection(ConnectTask task, Pool pool)
         {
+            // Remove any other (disconnected) entries for this server from the tree
+
+            var existingConnections = ConnectionsManager.XenConnections.Where(c =>
+                c.Hostname.Equals(task.Hostname) && !c.IsConnected).ToList();
+
+            foreach (var conn in existingConnections)
+                ConnectionsManager.ClearCacheAndRemoveConnection(conn);
+
             // add server name to history (if it's not already there)
             XenAdminConfigManager.Provider.UpdateServerHistory(HostnameWithPort);
 
@@ -945,18 +950,20 @@ namespace XenAdmin.Network
                 InvokeHelper.Invoke(XenAdminConfigManager.Provider.SaveSettingsIfRequired);
             }
 
-            log.InfoFormat("Connected to {0} ({1}:{2})", FriendlyName, taskHostname, task_port);
+            string name = string.IsNullOrEmpty(FriendlyName) || FriendlyName == task.Hostname
-            string name = string.IsNullOrEmpty(FriendlyName) || FriendlyName == taskHostname
+                              ? task.Hostname
-                              ? taskHostname
+                              : string.Format("{0} ({1})", FriendlyName, task.Hostname);
-                              : string.Format("{0} ({1})", FriendlyName, taskHostname);
             string title = string.Format(Messages.CONNECTING_NOTICE_TITLE, name);
             string msg = string.Format(Messages.CONNECTING_NOTICE_TEXT, name);
-            log.Info($"Connecting to {name} in progress.");
 
             ConnectAction = new DummyAction(title, msg);
+            SetPoolAndHostInAction(ConnectAction, pool, PoolOpaqueRef);
 
             ExpectPasswordIsCorrect = true;
             OnConnectionResult(true, null, null);
+
+            log.InfoFormat("Completed connection phase for pool {0} ({1}:{2}, {3}).",
+                FriendlyName, task.Hostname, task.Port, PoolOpaqueRef);
         }
 
         /// <summary>
@@ -974,13 +981,6 @@ namespace XenAdmin.Network
             return true;
         }
 
-        private void HandleConnectionTermination()
-        {
-            // clean up action so we dont stay open forever
-            if (ConnectAction != null)
-                ConnectAction.IsCompleted = true;
-        }
-
         private readonly object PromptLock = new object();
         /// <summary>
         /// Prompts the user for the changed password for a server.
@@ -1066,6 +1066,7 @@ namespace XenAdmin.Network
             // on the GUI thread to be included in this set of
             // updates, otherwise we might hose the gui thread
             // during an event storm (ie deleting 1000 vms)
+
             List<ObjectChange> events = new List<ObjectChange>();
 
             while (eventQueue.NotEmpty)
@@ -1073,43 +1074,24 @@ namespace XenAdmin.Network
 
             if (events.Count > 0)
             {
-                InvokeHelper.Invoke(delegate ()
+                InvokeHelper.Invoke(() =>
                 {
-                    try
+                    OnBeforeMajorChange(false);
-                    {
+                    bool fire = Cache.UpdateFrom(this, events);
-                        OnBeforeMajorChange(false);
+                    OnAfterMajorChange(false);
-                        bool fire = Cache.UpdateFrom(this, events);
-                        OnAfterMajorChange(false);
-
-                        if (fire)
-                            OnXenObjectsUpdated();
-                    }
-                    catch (Exception e)
-                    {
-                        log.Error("Exception updating cache.", e);
-#if DEBUG
-                        if (System.Diagnostics.Debugger.IsAttached)
-                            throw;
-#endif
-                    }
 
+                    if (fire)
+                        OnXenObjectsUpdated();
                 });
 
-                if (!cacheIsPopulated)
+                if (!CacheIsPopulated)
                 {
-                    cacheIsPopulated = true;
+                    lock (connectTaskLock)
-                    try
+                        heartbeat?.Start();
-                    {
+
-                        OnCachePopulated();
+                    CacheIsPopulated = true;
-                    }
+                    MarkConnectActionComplete();
-                    catch (Exception e)
+                    log.Info($"Connection to {Hostname} successful.");
-                    {
-                        log.Error("Exception calling OnCachePopulated.", e);
-#if DEBUG
-                        if (System.Diagnostics.Debugger.IsAttached)
-                            throw;
-#endif
-                    }
                 }
             }
         }
@@ -1123,7 +1105,6 @@ namespace XenAdmin.Network
             {
                 string title = string.Format(Messages.CONNECTION_OK_NOTICE_TITLE, Hostname);
                 string msg = string.Format(Messages.CONNECTION_OK_NOTICE_TEXT, Hostname);
-                log.Info($"Connection to {Hostname} successful.");
                 ConnectAction.Title = title;
                 ConnectAction.Description = msg;
 
@@ -1138,26 +1119,8 @@ namespace XenAdmin.Network
             }
         }
 
-        /// <summary>
-        /// Stops this connection's XenMetricsMonitor thread.
-        /// Expects to be locked under connectTaskLock.
-        /// </summary>
-        private void StopMonitor()
-        {
-            if (heartbeat != null)
-            {
-                heartbeat.Stop();
-                heartbeat = null;
-            }
-        }
-
         private const int DEFAULT_MAX_SESSION_LOGIN_ATTEMPTS = 3;
 
-        public static bool IsSimulatorConnection(string url)
-        {
-            return url.EndsWith(".db") || url.EndsWith(".xml") || url.EndsWith(".tmp");
-        }
-
         private readonly string eventNextConnectionGroupName = Guid.NewGuid().ToString();
 
         /// <summary>
@@ -1186,7 +1149,7 @@ namespace XenAdmin.Network
                 Session eventNextSession = DuplicateSession(EVENT_NEXT_TIMEOUT);
                 eventNextSession.ConnectionGroupName = eventNextConnectionGroupName; // this will force the eventNextSession onto its own set of TCP streams (see CA-108676)
 
-                cacheIsPopulated = false;
+                CacheIsPopulated = false;
                 session.CacheWarming = true;
 
                 string token = "";
@@ -1207,14 +1170,18 @@ namespace XenAdmin.Network
                             OnConnectionMessageChanged(string.Format(Messages.LABEL_SYNC, this.Hostname));
                         }
 
+                        log.Debug("Cache is warming. Starting XenObjectDownloader.GetAllObjects");
                         XenObjectDownloader.GetAllObjects(session, eventQueue, task.GetCancelled, ref token);
+                        log.Debug("Cache is warming. XenObjectDownloader.GetAllObjects finished successfully");
                         session.CacheWarming = false;
                     }
                     else
                     {
                         try
                         {
+                            log.Debug("Starting XenObjectDownloader.GetEvents");
                             XenObjectDownloader.GetEvents(eventNextSession, eventQueue, task.GetCancelled, ref token);
+                            log.Debug("Starting XenObjectDownloader.GetEvents finished successfully");
                             eventsExceptionLogged = false;
                         }
                         catch (Exception exn)
@@ -1225,8 +1192,8 @@ namespace XenAdmin.Network
                             log.DebugFormat("Exception (disruption is expected) in XenObjectDownloader.GetEvents: {0}", exn.GetType().Name);
 
                             // ignoring some exceptions when disruption is expected
-                            if (exn is System.IO.IOException ||
+                            if (exn is IOException ||
-                                (exn is WebException && ((exn as WebException).Status == WebExceptionStatus.KeepAliveFailure || (exn as WebException).Status == WebExceptionStatus.ConnectFailure)))
+                                (exn is WebException webEx && (webEx.Status == WebExceptionStatus.KeepAliveFailure || webEx.Status == WebExceptionStatus.ConnectFailure)))
                             {
                                 if (!eventsExceptionLogged)
                                 {
@@ -1269,16 +1236,10 @@ namespace XenAdmin.Network
                                 bool sameCoordinator = CoordinatorIPAddress == connection.CoordinatorIPAddress;
 
                                 if (sameRef && sameCoordinator)
-                                {
                                     throw new ConnectionExists(connection);
-                                }
-                                else
-                                {
-                                    // CA-15633: XenCenter does not allow connection to host 
-                                    //           on which backup is restored.
 
-                                    throw new BadRestoreDetected(connection);
+                                // CA-15633: XenCenter does not allow connection to host on which backup is restored.
-                                }
+                                throw new BadRestoreDetected(connection);
                             }
 
                             task.Connected = true;
@@ -1292,39 +1253,10 @@ namespace XenAdmin.Network
                                     : task.Hostname;
                         } // ConnectionsLock
 
-                        // Remove any other (disconnected) entries for this server from the tree
-                        List<IXenConnection> existingConnections = new List<IXenConnection>();
-                        foreach (IXenConnection connection in ConnectionsManager.XenConnections)
-                        {
-                            if (connection.Hostname.Equals(task.Hostname) && !connection.IsConnected)
-                            {
-                                existingConnections.Add(connection);
-                            }
-                        }
-                        foreach (IXenConnection connection in existingConnections)
-                        {
-                            ConnectionsManager.ClearCacheAndRemoveConnection(connection);
-                        }
-
-
                         log.DebugFormat("Getting server time for pool {0} ({1})...", FriendlyName, PoolOpaqueRef);
                         SetServerTimeOffset(session, pool.master.opaque_ref);
 
-                        // add server name to history (if it's not already there)
+                        HandleSuccessfulConnection(task, pool);
-                        XenAdminConfigManager.Provider.UpdateServerHistory(HostnameWithPort);
-
-                        HandleSuccessfulConnection(task.Hostname, task.Port);
-
-                        try
-                        {
-                            SetPoolAndHostInAction(ConnectAction, pool, PoolOpaqueRef);
-                        }
-                        catch (Exception e)
-                        {
-                            log.Error(e, e);
-                        }
-
-                        log.DebugFormat("Completed connection phase for pool {0} ({1}).", FriendlyName, PoolOpaqueRef);
                     }
 
                     EventsPending();
@@ -1398,7 +1330,10 @@ namespace XenAdmin.Network
                 ClearEventQueue();
 
                 connectTask = null;
-                HandleConnectionTermination();
+
+                // clean up action so we don't stay open forever
+                if (ConnectAction != null)
+                    ConnectAction.IsCompleted = true;
 
                 if (error is ServerNotSupported)
                 {
@@ -1617,7 +1552,7 @@ namespace XenAdmin.Network
         {
             get
             {
-                if (EventNextBlocked || IsSimulatorConnection(Hostname))
+                if (EventNextBlocked || IsSimulatedConnection)
                     return RECONNECT_SHORT_TIMEOUT_MS;
                 
                 return RECONNECT_HOST_TIMEOUT_MS;
@@ -1962,6 +1897,7 @@ namespace XenAdmin.Network
         }
 
         private bool disposed;
+
         protected virtual void Dispose(bool disposing)
         {
             if (!disposed)
@@ -1980,7 +1916,7 @@ namespace XenAdmin.Network
                     BeforeMajorChange = null;
                     AfterMajorChange = null;
                     XenObjectsUpdated = null;
-                    TimeSkewUpdated = null;
+
                     if (ReconnectionTimer != null)
                         ReconnectionTimer.Dispose();
                     if (cacheUpdateTimer != null)
@@ -2002,35 +1938,39 @@ namespace XenAdmin.Network
 
     public class ConnectionExists : DisconnectionException
     {
-        public IXenConnection connection;
+        protected readonly IXenConnection Connection;
 
         public ConnectionExists(IXenConnection connection)
         {
-            this.connection = connection;
+            Connection = connection;
         }
 
         public override string Message
         {
             get
             {
-                if (connection != null)
+                if (Connection == null)
-                    return string.Format(Messages.CONNECTION_EXISTS, connection.Hostname);
-                else
                     return Messages.CONNECTION_EXISTS_NULL;
+
+                return string.Format(Messages.CONNECTION_EXISTS, Connection.Hostname);
+
             }
         }
 
-        public virtual string GetDialogMessage(IXenConnection _this)
+        public virtual string GetDialogMessage()
         {
-            Pool p = Helpers.GetPool(connection);
+            if (Connection == null)
-            if (p == null)
+                return Messages.CONNECTION_EXISTS_NULL;
-                return String.Format(Messages.ALREADY_CONNECTED, _this.Hostname);
 
-            return String.Format(Messages.SUPPORTER_ALREADY_CONNECTED, _this.Hostname, p.Name());
+            Pool p = Helpers.GetPool(Connection);
+            if (p == null)
+                return string.Format(Messages.ALREADY_CONNECTED, Connection.Hostname);
+
+            return string.Format(Messages.SUPPORTER_ALREADY_CONNECTED, Connection.Hostname, p.Name());
         }
     }
 
-    class BadRestoreDetected : ConnectionExists
+    internal class BadRestoreDetected : ConnectionExists
     {
         public BadRestoreDetected(IXenConnection xc)
             : base(xc)
@@ -2041,11 +1981,14 @@ namespace XenAdmin.Network
         {
             get
             {
-                return String.Format(Messages.BAD_RESTORE_DETECTED, connection.Name);
+                if (Connection == null)
+                    return Messages.CONNECTION_EXISTS_NULL;
+
+                return string.Format(Messages.BAD_RESTORE_DETECTED, Connection.Name);
             }
         }
 
-        public override string GetDialogMessage(IXenConnection _this)
+        public override string GetDialogMessage()
         {
             return Message;
         }

XenModel/XenAPI-Extensions/Session.cs

@@ -163,7 +163,7 @@ namespace XenAPI
             //Sort roles from highest to lowest
             roles.Sort((r1, r2) => r2.CompareTo(r1));
             //Take the highest role
-            return roles[0].FriendlyName();
+            return roles.Count > 0 ? roles[0].FriendlyName() : Messages.UNKNOWN_AD_USER;
         }
     }
 }

XenModel/XenAPI/Marshalling.cs

@@ -30,6 +30,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections;
+using System.Linq;
 
 
 namespace XenAPI
@@ -45,7 +46,7 @@ namespace XenAPI
         /// <returns></returns>
         public static object convertStruct(Type t, Hashtable table)
         {
-            return t.GetConstructor(new Type[] {typeof(Hashtable)}).Invoke(new object[] {table});
+            return t.GetConstructor(new Type[] { typeof(Hashtable) }).Invoke(new object[] { table });
         }
 
         public static Type GetXenAPIType(string name)
@@ -55,31 +56,30 @@ namespace XenAPI
 
         public static bool ParseBool(Hashtable table, string key)
         {
-            var val = table[key];
+            bool.TryParse((string)table[key], out var result);
-            return val == null ? false : (bool)table[key];
+            return result;
         }
 
         public static DateTime ParseDateTime(Hashtable table, string key)
         {
-            var val = table[key];
+            DateTime.TryParse((string)table[key], out var result);
-            return val == null ? DateTime.MinValue : (DateTime)table[key];
+            return result;
         }
 
         public static double ParseDouble(Hashtable table, string key)
         {
-            var val = table[key];
+            double.TryParse((string)table[key], out var result);
-            return val == null ? 0.0 : (double)table[key];
+            return result;
         }
 
         public static Hashtable ParseHashTable(Hashtable table, string key)
         {
-            return (Hashtable)table[key];
+            return ParseSxpDict((string)table[key]);
         }
 
         public static long ParseLong(Hashtable table, string key)
         {
-            long result;
+            long.TryParse((string)table[key], out var result);
-            long.TryParse((string)table[key], out result);
             return result;
         }
 
@@ -90,14 +90,12 @@ namespace XenAPI
 
         public static string[] ParseStringArray(Hashtable table, string key)
         {
-            var val = (object[])table[key];
+            return ParseSxpList((string)table[key]).ToArray();
-            return val == null ? new string[0] : Array.ConvertAll(val, o => o.ToString());
         }
 
         public static long[] ParseLongArray(Hashtable table, string key)
         {
-            var val = (object[])table[key];
+            return ParseSxpList((string)table[key]).Select(long.Parse).ToArray();
-            return val == null ? new long[0] : Array.ConvertAll(val, o => long.Parse(o.ToString()));
         }
 
         public static XenRef<T> ParseRef<T>(Hashtable table, string key) where T : XenObject<T>
@@ -108,14 +106,85 @@ namespace XenAPI
 
         public static List<XenRef<T>> ParseSetRef<T>(Hashtable table, string key) where T : XenObject<T>
         {
-            var rs = (object[])table[key];
+            return ParseSxpList((string)table[key]).Select(XenRef<T>.Create).ToList();
-            return rs == null ? null : XenRef<T>.Create(rs);
         }
 
-        public static Dictionary<XenRef<T>, T> ParseMapRefRecord<T, U>(Hashtable table, string key) where T : XenObject<T>
+
+        private static Hashtable ParseSxpDict(string p)
         {
-            Hashtable map = ParseHashTable(table, key);
+            var result = new Hashtable();
-            return map == null ? null : XenRef<T>.Create<U>(map);
+
+            using (var enumerator = Tokenize(p).GetEnumerator())
+            {
+                if (!enumerator.MoveNext())
+                    return result;
+
+                while (enumerator.MoveNext())
+                {
+                    if (enumerator.Current == ")")
+                        break;
+
+                    enumerator.MoveNext();
+                    var key = enumerator.Current;
+                    enumerator.MoveNext();
+                    var value = enumerator.Current;
+                    enumerator.MoveNext();
+
+                    result[key] = value;
+                }
+
+                return result;
+            }
+        }
+
+        private static List<string> ParseSxpList(string p)
+        {
+            var result = new List<string>();
+
+            foreach (var token in Tokenize(p))
+            {
+                if (token == "(" || token == ")")
+                    continue;
+
+                result.Add(token);
+            }
+
+            return result;
+        }
+
+        private static IEnumerable<string> Tokenize(string str)
+        {
+            bool inStr = false;
+            int j = 0;
+
+            for (int i = 0; i < str.Length; i++)
+            {
+                switch (str[i])
+                {
+                    case '(':
+                    if (!inStr)
+                        yield return "(";
+                    break;
+                    case ')':
+                    if (!inStr)
+                        yield return ")";
+                    break;
+
+                    case '\'':
+                    case '"':
+                    if (!inStr)
+                    {
+                        inStr = true;
+                        j = i;
+                    }
+                    else if (str[i - 1] != '\\')
+                    {
+                        inStr = false;
+                        yield return str.Substring(j + 1, i - j - 1).Replace("\\\"", "\"").Replace("\\\'", "\'");
+                    }
+                    break;
+                }
+            }
         }
     }
 }

XenModel/XenModel.csproj

@@ -532,6 +532,7 @@
     <Compile Include="XenAPI\XenObject.cs" />
     <Compile Include="XenObjectDownloader.cs" />
     <Compile Include="XenAPI\XenRef.cs" />
+    <Compile Include="Db.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="..\Branding\Branding.ja.resx">