//客户端
int main()
{
//店里添加烤肉师傅、菜单、服务员等顾客
Barbucer* barbucer=new Barbucer();
Command* cmd= new BakeMuttonCmd(barbucer);
Command* cmd2=new ChickenWingCmd(barbucer);
Waiter* girl = new Waiter();
//点菜
girl->SetCmd(cmd);
girl->SetCmd(cmd2);
//服务员通知
girl->Notify();
system("pause");
return 0;
}
void Mutex::Unlock()
{
std::uint64_t head = 0;
if (mWaiters.CompareAndSwap(head, MUTEX_FREE_BIT))
return;
ExponentialBackoff backoff;
for (;;)
{
CRUNCH_ASSERT_MSG((head & MUTEX_FREE_BIT) == 0, "Attempting to release unlocked mutex");
Waiter* headPtr = Detail::WaiterList::GetPointer(head);
if (headPtr == nullptr)
{
CRUNCH_ASSERT((head & Detail::WaiterList::LOCK_BIT) == 0);
// No waiters, attempt to set free bit.
if (mWaiters.CompareAndSwap(head, MUTEX_FREE_BIT))
return;
}
else if (head & Detail::WaiterList::LOCK_BIT)
{
// Wait for lock release.
head = mWaiters.Load(MEMORY_ORDER_RELAXED);
}
else
{
// Try to pop first waiter off list and signal
std::uint64_t const newHead =
Detail::WaiterList::SetPointer(head, headPtr->next) +
Detail::WaiterList::ABA_ADDEND;
if (mWaiters.CompareAndSwap(head, newHead))
{
headPtr->Notify();
return;
}
}
backoff.Pause();
}
}