guard against duplicate DONE commands

lib/imap.js

@@ -39,7 +39,8 @@ var CRLF = '\r\n',
 // extension constants
 var IDLE_NONE = 1,
     IDLE_WAIT = 2,
-    IDLE_IDLING = 3;
+    IDLE_IDLING = 3,
+    IDLE_DONE = 4;
 
 function ImapConnection(options) {
   if (!(this instanceof ImapConnection))
@@ -763,9 +764,10 @@ ImapConnection.prototype.connect = function(loginCb) {
       if (state.isIdle) {
         if (state.ext.idle.state === IDLE_IDLING) {
           var timeDiff = Date.now() - state.ext.idle.timeStarted;
-          if (timeDiff >= state.ext.idle.MAX_WAIT)
+          if (timeDiff >= state.ext.idle.MAX_WAIT) {
+            state.ext.idle.state = IDLE_DONE;
             self._send('DONE');
-          else
+          } else
             state.tmrKeepalive = setTimeout(idleHandler, state.tmoKeepalive);
         } else if (!self.serverSupports('IDLE'))
           doKeepalive();
@@ -1578,8 +1580,10 @@ ImapConnection.prototype._send = function(cmdstr, cb) {
   }
 
   if (idle.state !== IDLE_NONE && cmdstr !== 'DONE') {
-    if (cmdstr !== undefined)
+    if (cmdstr !== undefined && idle.state !== IDLE_DONE) {
+      idle.state = IDLE_DONE;
       this._send('DONE');
+    }
     return;
   }