adding a new event for when definition is requested (#167)

* sending telemetry events for intellisense usage

src/Microsoft.SqlTools.ServiceLayer/LanguageServices/Completion/CompletionService.cs

@@ -0,0 +1,166 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System.Collections.Generic;
+using System.Threading;
+using Microsoft.SqlServer.Management.SqlParser.Intellisense;
+using Microsoft.SqlServer.Management.SqlParser.MetadataProvider;
+using Microsoft.SqlServer.Management.SqlParser.Parser;
+using Microsoft.SqlTools.ServiceLayer.Connection;
+using Microsoft.SqlTools.ServiceLayer.LanguageServices.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.LanguageServices.Completion
+{
+    /// <summary>
+    /// A service to create auto complete list for given script document 
+    /// </summary>
+    internal class CompletionService
+    {
+        private ConnectedBindingQueue BindingQueue { get; set; }
+
+        /// <summary>
+        /// Created new instance given binding queue
+        /// </summary>
+        public CompletionService(ConnectedBindingQueue bindingQueue)
+        {
+            BindingQueue = bindingQueue;
+        }
+
+        private ISqlParserWrapper sqlParserWrapper;
+
+        /// <summary>
+        /// SQL parser wrapper to create the completion list
+        /// </summary>
+        public ISqlParserWrapper SqlParserWrapper
+        {
+            get
+            {
+                if(this.sqlParserWrapper == null)
+                {
+                    this.sqlParserWrapper = new SqlParserWrapper();
+                }
+                return this.sqlParserWrapper;
+            }
+            set
+            {
+                this.sqlParserWrapper = value;
+            }
+        }
+
+        /// <summary>
+        /// Creates a completion list given connection and document info
+        /// </summary>
+        public AutoCompletionResult CreateCompletions(
+            ConnectionInfo connInfo,
+            ScriptDocumentInfo scriptDocumentInfo,
+            bool useLowerCaseSuggestions)
+        {
+            AutoCompletionResult result = new AutoCompletionResult();
+            // check if the file is connected and the file lock is available
+            if (scriptDocumentInfo.ScriptParseInfo.IsConnected && Monitor.TryEnter(scriptDocumentInfo.ScriptParseInfo.BuildingMetadataLock))
+            {
+                try
+                {
+                    QueueItem queueItem = AddToQueue(connInfo, scriptDocumentInfo.ScriptParseInfo, scriptDocumentInfo, useLowerCaseSuggestions);
+
+                    // wait for the queue item
+                    queueItem.ItemProcessed.WaitOne();
+                    var completionResult = queueItem.GetResultAsT<AutoCompletionResult>();
+                    if (completionResult != null && completionResult.CompletionItems != null && completionResult.CompletionItems.Length > 0)
+                    {
+                        result = completionResult;
+                    }
+                    else if (!ShouldShowCompletionList(scriptDocumentInfo.Token))
+                    {
+                        result.CompleteResult(AutoCompleteHelper.EmptyCompletionList);
+                    }
+                }
+                finally
+                {
+                    Monitor.Exit(scriptDocumentInfo.ScriptParseInfo.BuildingMetadataLock);
+                }
+            }
+
+            return result;
+        }
+
+        private QueueItem AddToQueue(
+            ConnectionInfo connInfo,
+            ScriptParseInfo scriptParseInfo,
+            ScriptDocumentInfo scriptDocumentInfo,
+            bool useLowerCaseSuggestions)
+        {
+            // queue the completion task with the binding queue    
+            QueueItem queueItem = this.BindingQueue.QueueBindingOperation(
+                key: scriptParseInfo.ConnectionKey,
+                bindingTimeout: LanguageService.BindingTimeout,
+                bindOperation: (bindingContext, cancelToken) =>
+                {
+                    return CreateCompletionsFromSqlParser(connInfo, scriptParseInfo, scriptDocumentInfo, bindingContext.MetadataDisplayInfoProvider);
+                },
+                timeoutOperation: (bindingContext) =>
+                {
+                    // return the default list if the connected bind fails
+                    return CreateDefaultCompletionItems(scriptParseInfo, scriptDocumentInfo, useLowerCaseSuggestions);
+                });
+            return queueItem;
+        }
+
+        private static bool ShouldShowCompletionList(Token token)
+        {
+            bool result = true;
+            if (token != null)
+            {
+                switch (token.Id)
+                {
+                    case (int)Tokens.LEX_MULTILINE_COMMENT:
+                    case (int)Tokens.LEX_END_OF_LINE_COMMENT:
+                        result = false;
+                        break;
+                }
+            }
+            return result;
+        }
+
+        private AutoCompletionResult CreateDefaultCompletionItems(ScriptParseInfo scriptParseInfo, ScriptDocumentInfo scriptDocumentInfo, bool useLowerCaseSuggestions)
+        {
+            AutoCompletionResult result = new AutoCompletionResult();
+            CompletionItem[] completionList = AutoCompleteHelper.GetDefaultCompletionItems(scriptDocumentInfo, useLowerCaseSuggestions);
+            result.CompleteResult(completionList);
+            return result;
+        }
+
+        private AutoCompletionResult CreateCompletionsFromSqlParser(
+            ConnectionInfo connInfo,
+            ScriptParseInfo scriptParseInfo,
+            ScriptDocumentInfo scriptDocumentInfo,
+            MetadataDisplayInfoProvider metadataDisplayInfoProvider)
+        {
+            AutoCompletionResult result = new AutoCompletionResult();
+            IEnumerable<Declaration> suggestions = SqlParserWrapper.FindCompletions(
+                scriptParseInfo.ParseResult,
+                scriptDocumentInfo.ParserLine,
+                scriptDocumentInfo.ParserColumn,
+                metadataDisplayInfoProvider);
+
+            // get the completion list from SQL Parser
+            scriptParseInfo.CurrentSuggestions = suggestions;
+
+            // convert the suggestion list to the VS Code format
+            CompletionItem[] completionList = AutoCompleteHelper.ConvertDeclarationsToCompletionItems(
+                scriptParseInfo.CurrentSuggestions,
+                scriptDocumentInfo.StartLine,
+                scriptDocumentInfo.StartColumn,
+                scriptDocumentInfo.EndColumn,
+                scriptDocumentInfo.TokenText);
+
+            result.CompleteResult(completionList);
+
+            //The bucket for number of milliseconds will take to send back auto complete list
+            connInfo.IntellisenseMetrics.UpdateMetrics(result.Duration, 1, (k2, v2) => v2 + 1);
+            return result;
+        }
+    }
+}