LimitTimer.hxx

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#ifndef _UTILS_LIMITTIMER_HXX_
#define _UTILS_LIMITTIMER_HXX_
 
#include <algorithm>
 
#include "executor/Timer.hxx"
 
class LimitTimer : public Timer
{
public:
    LimitTimer(ExecutorBase *ex, uint16_t update_delay_msec, uint8_t max_tokens,
               std::function<void()> callback)
        : Timer(ex->active_timers())
        , updateDelayMsec_(update_delay_msec)
        , bucket_(std::min(static_cast<uint8_t>(127), max_tokens))
        , bucketMax_(max_tokens)
        , needUpdate_(false)
        , callback_(callback)
    {
        HASSERT(callback);
    }
 
    ~LimitTimer()
    {
        cancel();
    }
 
    bool try_take()
    {
        if (bucket_ == bucketMax_)
        {
            start(MSEC_TO_NSEC(updateDelayMsec_));
        }
        if (bucket_ > 0)
        {
            --bucket_;
            return true;
        }
        else
        {
            needUpdate_ = true;
            return false;
        }
    }
 
    void take_no_callback()
    {
        if (bucket_ > 0)
        {
            --bucket_;
        }
    }
 
private:
    long long timeout() override
    {
        ++bucket_;
        if (needUpdate_)
        {
            needUpdate_ = false;
            callback_();
        }
        if (bucket_ >= bucketMax_)
        {
            return NONE;
        }
        else
        {
            return RESTART;
        }
    }
 
    uint16_t updateDelayMsec_;
 
    uint8_t bucket_ ;
 
    uint8_t bucketMax_ : 7;
 
    uint8_t needUpdate_ : 1;
 
    std::function<void()> callback_;
};
 
#endif // _UTILS_LIMITTIMER_HXX_