improve handling of negative welcome response upon connection

lib/imap.js

@@ -140,6 +140,7 @@ ImapConnection.prototype.connect = function(loginCb) {
     state.connected = false;
     state.authenticated = false;
     self.debug&&self.debug('[connection] FIN packet received. Disconnecting...');
+    clearTimeout(state.tmrConn);
     self.emit('end');
   });
 
@@ -154,9 +155,11 @@ ImapConnection.prototype.connect = function(loginCb) {
 
   state.conn.on('error', function(err) {
     clearTimeout(state.tmrConn);
+    err.level = 'socket';
     if (state.status === STATES.NOCONNECT)
-      loginCb(new Error('Unable to connect. Reason: ' + err));
-    self.emit('error', err);
+      loginCb(err);
+    else
+      self.emit('error', err);
     self.debug&&self.debug('[connection] Error occurred: ' + err);
   });
 
@@ -569,8 +572,16 @@ ImapConnection.prototype.connect = function(loginCb) {
             break;
           case 'NO':
           case 'BAD':
-            if (state.status === STATES.NOAUTH)
+            if (state.status === STATES.NOAUTH) {
+              clearTimeout(state.tmrConn);
+              var err = new Error('Received negative welcome (' + m[3] + ')');
+              err.level = 'protocol';
+              if (state.status === STATES.NOCONNECT)
+                loginCb(err);
+              else
+                self.emit('error', err);
               state.conn.end();
+            }
             break;
         }
       } else {