add readDirectory to LSHost

Author: Arthur Ozga

src/server/lsHost.ts

@@ -171,12 +171,16 @@ namespace ts.server {
             return this.host.fileExists(path);
         }
 
+        readFile(fileName: string): string {
+            return this.host.readFile(fileName);
+        }
+
         directoryExists(path: string): boolean {
             return this.host.directoryExists(path);
         }
 
-        readFile(fileName: string): string {
-            return this.host.readFile(fileName);
+        readDirectory(path: string, extensions?: string[], exclude?: string[], include?: string[]): string[] {
+            return this.host.readDirectory(path, exclude, exclude, include);
         }
 
         getDirectories(path: string): string[] {

src/services/completions.ts

@@ -330,17 +330,16 @@ namespace ts.Completions {
 
             fragment = normalizeSlashes(fragment);
 
-            const baseName = getBaseFileName(fragment); // TODO: brittle?
+            const baseName = getBaseFileName(fragment);
 
             // Remove the basename from our directory path
-            // TODO: (arozga) when is that used for filtering options later?
             fragment = getDirectoryPath(fragment);
 
             if (fragment === "") {
-                fragment = "." + directorySeparator; // TODO: (arozga) can we remove this?
+                fragment = "." + directorySeparator;
             }
 
-            fragment = ensureTrailingDirectorySeparator(fragment); // TODO: why is this necessary?
+            fragment = ensureTrailingDirectorySeparator(fragment);
 
             const absolutePath = normalizeAndPreserveTrailingSlash(isRootedDiskPath(fragment) ? fragment : combinePaths(scriptPath, fragment));
             const baseDirectory = getDirectoryPath(absolutePath);