User management support classes (#1856)

* WIP

* Fix nullable warnings in UserData class

* WIP2

* WIP

* Refresh database prototype classes

* Fix some typos & merge issues

* WIP

* WIP

* WIP

* Additional updates

* Remove unneded using

src/Microsoft.SqlTools.ServiceLayer/Utility/LanguageUtils.cs

@@ -0,0 +1,185 @@
+//
+// 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 Microsoft.SqlServer.Management.Common;
+using Microsoft.SqlServer.Management.Smo;
+
+namespace Microsoft.SqlTools.ServiceLayer.Utility
+{
+    /// <summary>
+    /// Summary description for CUtils.
+    /// </summary>
+    internal class LanguageUtils
+    {
+        /// <summary>
+        /// Gets alias for a language name.
+        /// </summary>
+        /// <param name="connectedServer"></param>
+        /// <param name="languageName"></param>
+        /// <returns>Returns string.Empty in case it doesn't find a matching languageName on the server</returns>
+        public static string GetLanguageAliasFromName(Server connectedServer,
+                                                        string languageName)
+        {
+            string languageAlias = string.Empty;
+
+            SetLanguageDefaultInitFieldsForDefaultLanguages(connectedServer);
+
+            foreach (Language lang in connectedServer.Languages)
+            {
+                if (lang.Name == languageName)
+                {
+                    languageAlias = lang.Alias;
+                    break;
+                }
+            }
+
+            return languageAlias;
+        }        
+
+        /// <summary>
+        /// Gets name for a language alias.
+        /// </summary>
+        /// <param name="connectedServer"></param>
+        /// <param name="languageAlias"></param>
+        /// <returns>Returns string.Empty in case it doesn't find a matching languageAlias on the server</returns>
+        public static string GetLanguageNameFromAlias(Server connectedServer,
+                                                        string languageAlias)
+        {
+            string languageName = string.Empty;
+
+            SetLanguageDefaultInitFieldsForDefaultLanguages(connectedServer);
+
+            foreach (Language lang in connectedServer.Languages)
+            {
+                if (lang.Alias == languageAlias)
+                {
+                    languageName = lang.Name;
+                    break;
+                }
+            }
+
+            return languageName;
+        }
+
+        /// <summary>
+        /// Gets lcid for a languageId.
+        /// </summary>
+        /// <param name="connectedServer"></param>
+        /// <param name="languageAlias"></param>
+        /// <returns>Throws exception in case it doesn't find a matching languageId on the server</returns>
+        public static int GetLcidFromLangId(Server connectedServer,
+                                                        int langId)
+        {
+            int lcid = -1; //Unacceptable Lcid.            
+
+            SetLanguageDefaultInitFieldsForDefaultLanguages(connectedServer);
+
+            foreach (Language lang in connectedServer.Languages)
+            {
+                if (lang.LangID == langId)
+                {
+                    lcid = lang.LocaleID;
+                    break;
+                }
+            }
+
+            if (lcid == -1) //Ideally this will never happen.
+            {
+                throw new ArgumentOutOfRangeException("langId", "This language id is not present in sys.syslanguages catalog.");
+            }
+
+            return lcid;
+        }
+
+        /// <summary>
+        /// Gets languageId for a lcid.
+        /// </summary>
+        /// <param name="connectedServer"></param>
+        /// <param name="languageAlias"></param>
+        /// <returns>Throws exception in case it doesn't find a matching lcid on the server</returns>
+        public static int GetLangIdFromLcid(Server connectedServer,
+                                                        int lcid)
+        {
+            int langId = -1; //Unacceptable LangId.            
+
+            SetLanguageDefaultInitFieldsForDefaultLanguages(connectedServer);
+
+            foreach (Language lang in connectedServer.Languages)
+            {
+                if (lang.LocaleID == lcid)
+                {
+                    langId = lang.LangID;
+                    break;
+                }
+            }
+
+            if (langId == -1) //Ideally this will never happen.
+            {
+                throw new ArgumentOutOfRangeException("lcid", "This locale id is not present in sys.syslanguages catalog.");
+            }
+
+            return langId;
+        }
+
+        /// <summary>
+        /// returns a language choice alias for that language
+        /// </summary>
+        /// <param name="langid"></param>
+        /// <returns></returns>
+        public static LanguageChoice GetLanguageChoiceAlias(Server connectedServer, 
+                                                                int lcid)
+        {
+            SetLanguageDefaultInitFieldsForDefaultLanguages(connectedServer);
+
+            foreach (Language smoL in connectedServer.Languages)
+            {
+                if (smoL.LocaleID == lcid)
+                {
+                    string alias = smoL.Alias;
+                    return new LanguageChoice(alias, lcid);
+                }
+            }
+            return new LanguageChoice(String.Empty, lcid);
+        }
+
+        /// <summary>
+        /// Sets exhaustive fields required for displaying and working with default languages in server, 
+        /// database and user dialogs as default init fields so that queries are not sent again and again.
+        /// </summary>
+        /// <param name="connectedServer">server on which languages will be enumerated</param>
+        public static void SetLanguageDefaultInitFieldsForDefaultLanguages(Server connectedServer)
+        {
+            string[] fieldsNeeded = new string[] { "Alias", "Name", "LocaleID", "LangID" };
+            connectedServer.SetDefaultInitFields(typeof(Language), fieldsNeeded);
+        }
+    }
+
+    #region interface - ILanguageLcidWithConnectionInfo - used by property editors to talk with data object
+    interface ILanguageLcidWithConnectionInfo
+    {
+        int Lcid { get; }
+        ServerConnection Connection { get; }
+    }
+    #endregion
+
+    #region class - LanguageChoice
+    internal class LanguageChoice
+    {
+        public string alias;
+        public System.Int32 lcid;
+        public LanguageChoice(string alias, System.Int32 lcid)
+        {
+            this.alias = alias;
+            this.lcid = lcid;
+        }
+
+        public override string ToString()
+        {
+            return alias;
+        }
+    }
+    #endregion
+}