Handle errors a little more gracefully

extension.js

@@ -4,6 +4,7 @@
 const Lang = imports.lang;
 const St = imports.gi.St;
 const Main = imports.ui.main;
+const Notify = imports.gi.Notify;
 const PanelMenu = imports.ui.panelMenu;
 
 const Me = imports.misc.extensionUtils.getCurrentExtension();
@@ -11,8 +12,8 @@ const TorControlClient = Me.imports.tor_control_client.TorControlClient;
 
 const TorIcon = 'tor';
 
-let torButton;
-let torControlClient;
+let torButton = null;
+let torControlClient = null;
 
 const TorButton = new Lang.Class({
     Name: 'TorButton',
@@ -43,14 +44,23 @@ function init(extensionMeta) {
 }
 
 function enable() {
-    torControlClient = new TorControlClient();
-    torButton = new TorButton();
-    Main.panel.addToStatusArea(torButton.Name, torButton);
+    try {
+        torControlClient = new TorControlClient();
+        torButton = new TorButton();
+        Main.panel.addToStatusArea(torButton.Name, torButton);
+    } catch (e) {
+        Main.notifyError('Error starting extension: ' + e);
+        disable();
+    }
 }
 
 function disable() {
-    torButton.destroy();
-    torButton = null;
-    torControlClient.close();
-    torControlClient = null;
+    if (torButton !== null) {
+        torButton.destroy();
+        torButton = null;
+    }
+    if (torControlClient !== null) {
+        torControlClient.close();
+        torControlClient = null;
+    }
 }

tor_control_client.js

@@ -14,15 +14,17 @@ const TorControlClient = new Lang.Class({
     },
 
     close: function() {
-        this._outputStream.close(null);
-        this._inputStream.close(null);
+        if (this._connection.is_connected()) {
+            this._outputStream.close(null);
+            this._inputStream.close(null);
+        }
     },
 
     _connect: function() {
         var socketClient = new Gio.SocketClient();
-        var connection = socketClient.connect_to_host('127.0.0.1:9051', null, null);
-        this._inputStream = new Gio.DataInputStream({base_stream: connection.get_input_stream()});
-        this._outputStream = new Gio.DataOutputStream({base_stream: connection.get_output_stream()});
+        this._connection = socketClient.connect_to_host('127.0.0.1:9051', null, null);
+        this._inputStream = new Gio.DataInputStream({base_stream: this._connection.get_input_stream()});
+        this._outputStream = new Gio.DataOutputStream({base_stream: this._connection.get_output_stream()});
     },
 
     _updateProtocolInfo: function() {