Lock.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Trace/Config.h"
#include "Trace/Detail/Atomic.h"
#include "Platform.h"
 
#if TRACE_PRIVATE_MINIMAL_ENABLED
 
namespace UE {
namespace Trace {
namespace Private {
 
struct FLock 
{
    FLock(volatile uint8* InLock)
        : Lock(InLock)
    {
        CyclesPerSecond = TimeGetFrequency();
        StartSeconds = GetTime();
 
        while (!AtomicCompareExchangeAcquire(Lock, uint8(1u), uint8(0u)))
        {
            ThreadSleep(0);
 
            if (TimedOut())
            {
                break;
            }
        }
    }
 
    ~FLock()
    {
        AtomicExchangeRelease(Lock, uint8(0u));
    }
 
    double GetTime()
    {
        return static_cast<double>(TimeGetTimestamp()) / static_cast<double>(CyclesPerSecond);
    }
 
    bool TimedOut()
    {
        const double WaitTime = GetTime() - StartSeconds;
        return WaitTime > MaxWaitSeconds;
    }
 
    volatile uint8* Lock;
    uint64 CyclesPerSecond;
    double StartSeconds;
    inline const static double MaxWaitSeconds = 1.0;
};
 
}}}
 
#endif