ConditionQueue insertQueue;
ConditionQueue removeQueue; 
int numRemoveCalled = 0; // # of times remove has been called
int numInsertCalled = 0; // # of times insert has been called

int
FIFOBBQ::remove() {
    int item;
    int myPosition;
    CV *myCV, *nextWaiter;

    lock.acquire();

    myPosition = numRemoveCalled++;
    mycv = new CV;  // Create a new condition variable to wait on.
    removeQueue.append(myCV);

// Even if I am woken up, wait until it is my turn.
    while (front < myPosition || front == nextEmpty) {
        mycv->Wait(&lock);
    }

    delete self;    // The condition variable is no longer needed.
    item = items[front % size];
    front++;

// Wake up the next thread waiting in insert, if any.
    nextWaiter = insertQueue.removeFromFront();
    if (nextWaiter != NULL)
        nextWaiter->Signal(&lock);
    lock.release();
    return item;
}