Add watcher on settings to restart clangd if needed

src/config-watcher.ts

@@ -0,0 +1,18 @@
+import * as vscode from 'vscode';
+
+const WATCHED_SETTINGS: String[] =
+    ['path', 'arguments', 'trace', 'fallbackFlags', 'semanticHighlighting'];
+
+async function handleConfigurationChanged(e: vscode.ConfigurationChangeEvent) {
+  for (let setting of WATCHED_SETTINGS) {
+    if (e.affectsConfiguration(`clangd.${setting}`)) {
+      vscode.commands.executeCommand('clangd.restart');
+      break;
+    }
+  }
+}
+
+export function activate(context: vscode.ExtensionContext) {
+  context.subscriptions.push(
+      vscode.workspace.onDidChangeConfiguration(handleConfigurationChanged))
+}

src/extension.ts

@@ -1,6 +1,7 @@
 import * as vscode from 'vscode';
 
 import {ClangdContext} from './clangd-context';
+import * as ConfigWatcher from './config-watcher';
 
 /**
  *  This method is called when the extension is activated. The extension is
@@ -13,6 +14,9 @@ export async function activate(context: vscode.ExtensionContext) {
   const clangdContext = new ClangdContext;
   context.subscriptions.push(clangdContext);
 
+  // Listen for settings changes
+  ConfigWatcher.activate(context);
+
   // An empty place holder for the activate command, otherwise we'll get an
   // "command is not registered" error.
   context.subscriptions.push(