Add table and view metadata messges (#296)

* Add SMO table property lookup event

* Fix a couple bugs in column metadata

* Add GetView metadata message

src/Microsoft.SqlTools.ServiceLayer/Metadata/SmoMetadataFactory.cs

@@ -0,0 +1,122 @@
+//
+// 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.Collections.Generic;
+using System.Data.Common;
+using System.Data.SqlClient;
+using Microsoft.SqlServer.Management.Common;
+using Microsoft.SqlServer.Management.Smo;
+using Microsoft.SqlTools.ServiceLayer.Connection.ReliableConnection;
+using Microsoft.SqlTools.ServiceLayer.Utility;
+
+namespace Microsoft.SqlTools.ServiceLayer.Metadata
+{
+    /// <summary>
+    /// Interface for a factory that generates metadata for an object to edit
+    /// </summary>
+    public interface IMetadataFactory
+    {
+        /// <summary>
+        /// Generates a edit-ready metadata object
+        /// </summary>
+        /// <param name="connection">Connection to use for getting metadata</param>
+        /// <param name="objectName">Name of the object to return metadata for</param>
+        /// <param name="objectType">Type of the object to return metadata for</param>
+        /// <returns>Metadata about the object requested</returns>
+        TableMetadata GetObjectMetadata(DbConnection connection, string schemaName, string objectName, string objectType);
+    }
+
+    /// <summary>
+    /// Factory that generates metadata using a combination of SMO and SqlClient metadata
+    /// </summary>
+    public class SmoMetadataFactory : IMetadataFactory
+    {
+        /// <summary>
+        /// Generates a edit-ready metadata object using SMO
+        /// </summary>
+        /// <param name="connection">Connection to use for getting metadata</param>
+        /// <param name="objectName">Name of the object to return metadata for</param>
+        /// <param name="objectType">Type of the object to return metadata for</param>
+        /// <returns>Metadata about the object requested</returns>
+        public TableMetadata GetObjectMetadata(DbConnection connection, string schemaName, string objectName, string objectType)
+        {
+            // Get a connection to the database for SMO purposes
+            SqlConnection sqlConn = connection as SqlConnection;
+            if (sqlConn == null)
+            {
+                // It's not actually a SqlConnection, so let's try a reliable SQL connection
+                ReliableSqlConnection reliableConn = connection as ReliableSqlConnection;
+                if (reliableConn == null)
+                {
+                    // If we don't have connection we can use with SMO, just give up on using SMO
+                    return null;
+                }
+
+                // We have a reliable connection, use the underlying connection
+                sqlConn = reliableConn.GetUnderlyingConnection();
+            }
+
+            // Connect with SMO and get the metadata for the table
+            Server server = new Server(new ServerConnection(sqlConn));
+            Database database = server.Databases[sqlConn.Database];
+            TableViewTableTypeBase smoResult;
+            switch (objectType.ToLowerInvariant())
+            {
+                case "table":                    
+                    Table table = string.IsNullOrEmpty(schemaName) ? new Table(database, objectName) : new Table(database, objectName, schemaName);
+                    table.Refresh();
+                    smoResult = table;
+                    break;
+                case "view":
+                    View view = string.IsNullOrEmpty(schemaName) ? new View(database, objectName) : new View(database, objectName, schemaName);
+                    view.Refresh();
+                    smoResult = view;
+                    break;
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(objectType), SR.EditDataUnsupportedObjectType(objectType));
+            }
+            if (smoResult == null)
+            {
+                throw new ArgumentOutOfRangeException(nameof(objectName), SR.EditDataObjectMetadataNotFound);
+            }
+
+            // Generate the edit column metadata
+            List<ColumnMetadata> editColumns = new List<ColumnMetadata>();
+            for (int i = 0; i < smoResult.Columns.Count; i++)
+            {
+                Column smoColumn = smoResult.Columns[i];
+
+                // The default value may be escaped
+                string defaultValue = smoColumn.DefaultConstraint == null
+                    ? null
+                    : SqlScriptFormatter.UnwrapLiteral(smoColumn.DefaultConstraint.Text);
+
+                ColumnMetadata column = new ColumnMetadata
+                {
+                    DefaultValue = defaultValue,
+                    EscapedName = SqlScriptFormatter.FormatIdentifier(smoColumn.Name),
+                    Ordinal = i,
+                };
+                editColumns.Add(column);
+            }
+
+            // Only tables can be memory-optimized
+            Table smoTable = smoResult as Table;
+            bool isMemoryOptimized = smoTable != null && smoTable.IsMemoryOptimized;
+
+            // Escape the parts of the name
+            string[] objectNameParts = {smoResult.Schema, smoResult.Name};
+            string escapedMultipartName = SqlScriptFormatter.FormatMultipartIdentifier(objectNameParts);
+
+            return new TableMetadata
+            {
+                Columns = editColumns.ToArray(),
+                EscapedMultipartName = escapedMultipartName,
+                IsMemoryOptimized = isMemoryOptimized,
+            };
+        }
+    }
+}