Avoid throwing exception in LangageService for OE connections (#361)

* Ensure connection open for OE queries and fix connection disposal
- Dispose connection in Metadata service, to ensure we cleanly dispose and don't rely on garbage colleciton
- Fixed issue where if the connection was closed, expanding databases in the Server would fail. This is because SMO doesn't always reopen the connection, certainly not for Server level queries. The solution is to always check if open and reopen.
- Added unit tests for this, which required mocking the relevant IsOpen / OpenConnection methods. Refactored SMO wrapper calls into a dedicated class file to handle this

* Avoid throwing exception in LangageService for OE connections
- Handle non-File URIs by skipping language service binding in those cases. Added test for this

- VSCode passes untitled:, git: and other paths, often without a '/'. Updated logic to handle this.

* Handle windows file paths

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

@@ -507,6 +507,11 @@ namespace Microsoft.SqlTools.ServiceLayer.LanguageServices
             if (scriptInfo.IsConnected)
             {
                 var scriptFile = AutoCompleteHelper.WorkspaceServiceInstance.Workspace.GetFile(info.OwnerUri);
+                if (scriptFile == null)
+                {
+                    return;
+                }
+                
                 LanguageService.Instance.ParseAndBind(scriptFile, info);
 
                 if (Monitor.TryEnter(scriptInfo.BuildingMetadataLock, LanguageService.OnConnectionWaitTimeout))

src/Microsoft.SqlTools.ServiceLayer/Workspace/Contracts/ScriptFile.cs

@@ -121,7 +121,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Workspace.Contracts
             FilePath = filePath;
             ClientFilePath = clientFilePath;
             IsAnalysisEnabled = true;
-            IsInMemory = Workspace.IsPathInMemory(filePath);
+            IsInMemory = Workspace.IsPathInMemoryOrNonFileUri(filePath);
 
             SetFileContents(textReader.ReadToEnd());
         }

src/Microsoft.SqlTools.ServiceLayer/Workspace/Workspace.cs

@@ -23,6 +23,13 @@ namespace Microsoft.SqlTools.ServiceLayer.Workspace
     {
         #region Private Fields
 
+        private static readonly HashSet<string> fileUriSchemes = new HashSet<string>(StringComparer.OrdinalIgnoreCase) 
+        {
+            "file",
+            "untitled",
+            "tsqloutput"
+        };
+
         private Dictionary<string, ScriptFile> workspaceFiles = new Dictionary<string, ScriptFile>();
 
         #endregion
@@ -81,7 +88,11 @@ namespace Microsoft.SqlTools.ServiceLayer.Workspace
         public virtual ScriptFile GetFile(string filePath)
         {
             Validate.IsNotNullOrWhitespaceString("filePath", filePath);
-
+            if (IsNonFileUri(filePath))
+            {
+                return null;
+            }
+            
             // Resolve the full file path 
             string resolvedFilePath = this.ResolveFilePath(filePath);
             string keyName = resolvedFilePath.ToLower();
@@ -108,7 +119,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Workspace
         
         private string ResolveFilePath(string filePath)
         {
-            if (!IsPathInMemory(filePath))
+            if (!IsPathInMemoryOrNonFileUri(filePath))
             {
                 if (filePath.StartsWith(@"file://"))
                 {
@@ -141,20 +152,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Workspace
 
             return filePath;
         }
-
-        internal static bool IsPathInMemory(string filePath)
-        {
-            // When viewing SqlTools files in the Git diff viewer, VS Code
-            // sends the contents of the file at HEAD with a URI that starts
-            // with 'inmemory'.  Untitled files which have been marked of
-            // type SqlTools have a path starting with 'untitled'.
-            return
-                filePath.StartsWith("inmemory:") ||
-                filePath.StartsWith("tsqloutput:") ||
-                filePath.StartsWith("git:") ||            
-                filePath.StartsWith("untitled:");
-        }
-
+        
         /// <summary>
         /// Unescapes any escaped [, ] or space characters. Typically use this before calling a
         /// .NET API that doesn't understand PowerShell escaped chars.
@@ -181,6 +179,10 @@ namespace Microsoft.SqlTools.ServiceLayer.Workspace
         public ScriptFile GetFileBuffer(string filePath, string initialBuffer)
         {
             Validate.IsNotNullOrWhitespaceString("filePath", filePath);
+            if (IsNonFileUri(filePath))
+            {
+                return null;
+            }
 
             // Resolve the full file path 
             string resolvedFilePath = this.ResolveFilePath(filePath);
@@ -222,7 +224,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Workspace
 
         internal string GetBaseFilePath(string filePath)
         {
-            if (IsPathInMemory(filePath))
+            if (IsPathInMemoryOrNonFileUri(filePath))
             {
                 // If the file is in memory, use the workspace path
                 return this.WorkspacePath;
@@ -257,7 +259,45 @@ namespace Microsoft.SqlTools.ServiceLayer.Workspace
                         relativePath));
 
             return combinedPath;
-        }
+        }
+        internal static bool IsPathInMemoryOrNonFileUri(string path)
+        {
+            string scheme = GetScheme(path);
+            if (!string.IsNullOrEmpty(scheme))
+            {
+                return !scheme.Equals("file");
+            }
+            return false;
+        }
+
+        public static string GetScheme(string uri)
+        {
+            string windowsFilePattern = @"^(?:[\w]\:|\\)";
+            if (Regex.IsMatch(uri, windowsFilePattern))
+            {
+                // Handle windows paths, these conflict with other "URI" handling
+                return null;
+            }
+
+            // Match anything that starts with xyz:, as VSCode send URIs in the format untitled:, git: etc.
+            string pattern = "^([a-z][a-z0-9+.-]*):";
+            Match match = Regex.Match(uri, pattern);
+            if (match != null && match.Success)
+            {
+                return match.Groups[1].Value;
+            }
+            return null;
+        }
+
+        private bool IsNonFileUri(string path)
+        {
+            string scheme = GetScheme(path);
+            if (!string.IsNullOrEmpty(scheme))
+            {
+                return !fileUriSchemes.Contains(scheme); ;
+            }
+            return false;
+        }
 
         #endregion  
 

test/Microsoft.SqlTools.ServiceLayer.UnitTests/Workspace/WorkspaceTests.cs

@@ -196,5 +196,37 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.Workspace
             // verify the file is being tracked by workspace
             Assert.True(workspaceService.Workspace.ContainsFile(TestObjects.ScriptUri));
         }
+
+        [Fact]
+        public void DontBindToObjectExplorerConnectEvents()
+        {
+            // when I ask for a non-file object in the workspace, it should return null
+            var workspace = new ServiceLayer.Workspace.Workspace();
+            ScriptFile file = workspace.GetFile("objectexplorer://server;database=database;user=user");            
+            Assert.Null(file);
+
+            // when I ask for a file, it should return the file
+            string tempFile = Path.GetTempFileName();
+            string fileContents = "hello world";
+            File.WriteAllText(tempFile, fileContents);
+
+            file = workspace.GetFile(tempFile);
+            Assert.Equal(fileContents, file.Contents);
+
+            if (tempFile.StartsWith("/"))
+            {
+                tempFile = tempFile.Substring(1);
+            }
+            file = workspace.GetFile("file://" + tempFile);
+            Assert.Equal(fileContents, file.Contents);
+
+            file = workspace.GetFileBuffer("untitled://"+ tempFile, fileContents);
+            Assert.Equal(fileContents, file.Contents);
+
+            // For windows files, just check scheme is null since it's hard to mock file contents in these
+            Assert.Null(ServiceLayer.Workspace.Workspace.GetScheme(@"C:\myfile.sql"));
+            Assert.Null(ServiceLayer.Workspace.Workspace.GetScheme(@"\\myfile.sql"));
+        }
+
     }
 }