class InterProcessLock(object):
    def lock(self, delta=0.01):
        while True:
            try:
                self.lockNoWait()
                break;
            except:
                time.sleep(delta)
    
    def __init__(self, name=None):
        self.mutex = None
        if not name:
            name = sys.argv[0]
        self.name = base64.b64encode(name).replace('=','')

    def lockNoWait(self):
        self.mutex = win32event.CreateMutex(None, 0, self.name)
        if win32api.GetLastError() == winerror.ERROR_ALREADY_EXISTS:
            self.mutex.Close()
            self.mutex = None
            raise Exception('acquired')

    def unlock(self):
        self.mutex.Close()

    def lockNoWait(self):
        try:
            self.mutex = win32event.CreateMutex(None, 0, self.name)
        except win32api.error, e:
            #print str(e)
            if self.mutex is not None:
                self.mutex.Close()
                self.mutex = None
            #else:
                #print 'self.mutex == None'

            raise Exception('acquired')