/mordor/streams/throttle.h

#ifndef __MORDOR_THROTTLE_STREAM_H__
#define __MORDOR_THROTTLE_STREAM_H__
// Copyright (c) 2009 - Mozy, Inc.

#include <boost/function.hpp>

#include "filter.h"

namespace Mordor {

class TimerManager;

/// @note In practice, ThrottleStream cannot throttle much slower than 800bps
/// (due to refusing to sleep for more than a tenth of a second at a time)
class ThrottleStream : public FilterStream
{
public:
    /// @param dg Returns the current throttle value, in bps (BITS per second).
    /// Either 0 or ~0u means to not throttle at the moment.
    ThrottleStream(Stream::ptr parent, boost::function<unsigned int ()> dg,
        TimerManager &timerManager, bool own = true)
        : FilterStream(parent, own),
          m_dg(dg),
          m_read(0),
          m_written(0),
          m_readTimestamp(0),
          m_writeTimestamp(0),
          m_timerManager(&timerManager)
    {}
    ThrottleStream(Stream::ptr parent, boost::function<unsigned int ()> dg,
        bool own = true)
        : FilterStream(parent, own),
          m_dg(dg),
          m_read(0),
          m_written(0),
          m_readTimestamp(0),
          m_writeTimestamp(0),
          m_timerManager(NULL)
    {}

    using FilterStream::read;
    size_t read(Buffer &b, size_t len);
    using FilterStream::write;
    size_t write(const Buffer &b, size_t len);

private:
    boost::function<unsigned int ()> m_dg;
    size_t m_read, m_written;
    unsigned long long m_readTimestamp, m_writeTimestamp;
    TimerManager *m_timerManager;
};

}

#endif