'(Private) Processes the next command in the queue.'

def sendNextCommand(self):

    ftpCommand = self.popCommandQueue()
    if (ftpCommand is None):
        self.nextDeferred = None
        return
    if (not ftpCommand.ready):
        self.actionQueue.insert(0, ftpCommand)
        reactor.callLater(1.0, self.sendNextCommand)
        self.nextDeferred = None
        return
    if (ftpCommand.text == 'PORT'):
        self.generatePortCommand(ftpCommand)
    if self.debug:
        log.msg(('<--    %s' % ftpCommand.text))
    self.nextDeferred = ftpCommand.deferred
    self.sendLine(ftpCommand.text)
