◆ Wait() [4/6]

bool System.Threading.SemaphoreSlim.Wait	(	int	millisecondsTimeout,
		CancellationToken	cancellationToken )
inline
Definition at line 155 of file SemaphoreSlim.cs.
    {
        CheckDispose();
        if (millisecondsTimeout < -1)
        {
            throw new ArgumentOutOfRangeException("millisecondsTimeout", millisecondsTimeout, SR.SemaphoreSlim_Wait_TimeoutWrong);
        }
        cancellationToken.ThrowIfCancellationRequested();
        if (millisecondsTimeout == 0 && m_currentCount == 0)
        {
            return false;
        }
        uint startTime = 0u;
        if (millisecondsTimeout != -1 && millisecondsTimeout > 0)
        {
            startTime = TimeoutHelper.GetTime();
        }
        bool flag = false;
        Task<bool> task = null;
        bool lockTaken = false;
        CancellationTokenRegistration cancellationTokenRegistration = cancellationToken.UnsafeRegister(s_cancellationTokenCanceledEventHandler, this);
        try
        {
            if (m_currentCount == 0)
            {
                int num = SpinWait.SpinCountforSpinBeforeWait * 4;
                SpinWait spinWait = default(SpinWait);
                while (spinWait.Count < num)
                {
                    spinWait.SpinOnce(-1);
                    if (m_currentCount != 0)
                    {
                        break;
                    }
                }
            }
            Monitor.Enter(m_lockObjAndDisposed, ref lockTaken);
            m_waitCount++;
            if (m_asyncHead != null)
            {
                task = WaitAsync(millisecondsTimeout, cancellationToken);
            }
            else
            {
                OperationCanceledException ex = null;
                if (m_currentCount == 0)
                {
                    if (millisecondsTimeout == 0)
                    {
                        return false;
                    }
                    try
                    {
                        flag = WaitUntilCountOrTimeout(millisecondsTimeout, startTime, cancellationToken);
                    }
                    catch (OperationCanceledException ex2)
                    {
                        ex = ex2;
                    }
                }
                if (m_currentCount > 0)
                {
                    flag = true;
                    m_currentCount--;
                }
                else if (ex != null)
                {
                    throw ex;
                }
                if (m_waitHandle != null && m_currentCount == 0)
                {
                    m_waitHandle.Reset();
                }
            }
        }
        finally
        {
            if (lockTaken)
            {
                m_waitCount--;
                Monitor.Exit(m_lockObjAndDisposed);
            }
            cancellationTokenRegistration.Dispose();
        }
        return task?.GetAwaiter().GetResult() ?? flag;
    }