Add IntelliSense binding queue (#73)

* Initial code for binding queue

* Fix-up some of the timeout wait code

* Add some initial test code

* Add missing test file

* Update the binding queue tests

* Add more test coverage and refactor a bit.  Disable reliabile connection until we can fix it..it's holding an open data reader connection.

* A few more test updates

* Initial integrate queue with language service.

* Hook up the connected binding queue into al binding calls.

* Cleanup comments and remove dead code

* More missing comments

* Fix build break.  Reenable ReliabileConnection.

* Revert all changes to SqlConnectionFactory

* Resolve merge conflicts

* Cleanup some more of the timeouts and sync code

* Address code review feedback

* Address more code review feedback

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

@@ -0,0 +1,109 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using System.Data.SqlClient;
+using Microsoft.SqlServer.Management.Common;
+using Microsoft.SqlServer.Management.SmoMetadataProvider;
+using Microsoft.SqlServer.Management.SqlParser.Binder;
+using Microsoft.SqlServer.Management.SqlParser.MetadataProvider;
+using Microsoft.SqlTools.ServiceLayer.Connection;
+using Microsoft.SqlTools.ServiceLayer.Connection.Contracts;
+using Microsoft.SqlTools.ServiceLayer.SqlContext;
+using Microsoft.SqlTools.ServiceLayer.Workspace;
+
+namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
+{
+    /// <summary>
+    /// ConnectedBindingQueue class for processing online binding requests
+    /// </summary>
+    public class ConnectedBindingQueue : BindingQueue<ConnectedBindingContext>
+    {
+        internal const int DefaultBindingTimeout = 60000;
+
+        internal const int DefaultMinimumConnectionTimeout = 30;
+
+        /// <summary>
+        /// Gets the current settings
+        /// </summary>
+        internal SqlToolsSettings CurrentSettings
+        {
+            get { return WorkspaceService<SqlToolsSettings>.Instance.CurrentSettings; }
+        }
+
+        /// <summary>
+        /// Generate a unique key based on the ConnectionInfo object
+        /// </summary>
+        /// <param name="connInfo"></param>
+        private string GetConnectionContextKey(ConnectionInfo connInfo)
+        {
+            ConnectionDetails details = connInfo.ConnectionDetails;
+            return string.Format("{0}_{1}_{2}_{3}",
+                details.ServerName ?? "NULL",
+                details.DatabaseName ?? "NULL",
+                details.UserName ?? "NULL",
+                details.AuthenticationType ?? "NULL"
+            );
+        }
+
+        /// <summary>
+        /// Use a ConnectionInfo item to create a connected binding context
+        /// </summary>
+        /// <param name="connInfo"></param>
+        public virtual string AddConnectionContext(ConnectionInfo connInfo)
+        {
+            if (connInfo == null)
+            {
+                return string.Empty;
+            }
+
+            // lookup the current binding context
+            string connectionKey = GetConnectionContextKey(connInfo);
+            IBindingContext bindingContext = this.GetOrCreateBindingContext(connectionKey);
+
+            try
+            {
+                // increase the connection timeout to at least 30 seconds and and build connection string
+                // enable PersistSecurityInfo to handle issues in SMO where the connection context is lost in reconnections
+                int? originalTimeout = connInfo.ConnectionDetails.ConnectTimeout;
+                bool? originalPersistSecurityInfo = connInfo.ConnectionDetails.PersistSecurityInfo;
+                connInfo.ConnectionDetails.ConnectTimeout = Math.Max(DefaultMinimumConnectionTimeout, originalTimeout ?? 0);
+                connInfo.ConnectionDetails.PersistSecurityInfo = true;
+                string connectionString = ConnectionService.BuildConnectionString(connInfo.ConnectionDetails);
+                connInfo.ConnectionDetails.ConnectTimeout = originalTimeout;
+                connInfo.ConnectionDetails.PersistSecurityInfo = originalPersistSecurityInfo;
+
+                // open a dedicated binding server connection
+                SqlConnection sqlConn = new SqlConnection(connectionString);
+                if (sqlConn != null)
+                {
+                    sqlConn.Open();
+
+                    // populate the binding context to work with the SMO metadata provider
+                    ServerConnection serverConn = new ServerConnection(sqlConn);                            
+                    bindingContext.SmoMetadataProvider = SmoMetadataProvider.CreateConnectedProvider(serverConn);
+                    bindingContext.MetadataDisplayInfoProvider = new MetadataDisplayInfoProvider();
+                    bindingContext.MetadataDisplayInfoProvider.BuiltInCasing =
+                        this.CurrentSettings.SqlTools.IntelliSense.LowerCaseSuggestions.Value
+                            ? CasingStyle.Lowercase : CasingStyle.Uppercase;
+                    bindingContext.Binder = BinderProvider.CreateBinder(bindingContext.SmoMetadataProvider);                           
+                    bindingContext.ServerConnection = serverConn;
+                    bindingContext.BindingTimeout = ConnectedBindingQueue.DefaultBindingTimeout;
+                    bindingContext.IsConnected = true;
+                }
+            }
+            catch (Exception)
+            {
+                bindingContext.IsConnected = false;
+            }
+            finally
+            {
+                bindingContext.BindingLocked.Set();                
+            }
+
+            return connectionKey;
+        }
+    }
+}