timer.h

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2020 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#ifndef BITCOIN_LOGGING_TIMER_H
#define BITCOIN_LOGGING_TIMER_H
 
#include <logging.h>
#include <util/macros.h>
#include <util/time.h>
#include <util/types.h>
 
#include <chrono>
#include <string>
 
 
namespace BCLog {
 
template <typename TimeType>
class Timer
{
public:
    Timer(
        std::string prefix,
        std::string end_msg,
        BCLog::LogFlags log_category = BCLog::LogFlags::ALL) :
            m_prefix(std::move(prefix)),
            m_title(std::move(end_msg)),
            m_log_category(log_category)
    {
        this->Log(strprintf("%s started", m_title));
        m_start_t = GetTime<std::chrono::microseconds>();
    }
 
    ~Timer()
    {
        this->Log(strprintf("%s completed", m_title));
    }
 
    void Log(const std::string& msg)
    {
        const std::string full_msg = this->LogMsg(msg);
 
        if (m_log_category == BCLog::LogFlags::ALL) {
            LogPrintf("%s\n", full_msg);
        } else {
            LogPrint(m_log_category, "%s\n", full_msg);
        }
    }
 
    std::string LogMsg(const std::string& msg)
    {
        const auto end_time = GetTime<std::chrono::microseconds>() - m_start_t;
        if (m_start_t.count() <= 0) {
            return strprintf("%s: %s", m_prefix, msg);
        }
 
        if constexpr (std::is_same<TimeType, std::chrono::microseconds>::value) {
            return strprintf("%s: %s (%iμs)", m_prefix, msg, end_time.count());
        } else if constexpr (std::is_same<TimeType, std::chrono::milliseconds>::value) {
            return strprintf("%s: %s (%.2fms)", m_prefix, msg, end_time.count() * 0.001);
        } else if constexpr (std::is_same<TimeType, std::chrono::seconds>::value) {
            return strprintf("%s: %s (%.2fs)", m_prefix, msg, end_time.count() * 0.000001);
        } else {
            static_assert(ALWAYS_FALSE<TimeType>, "Error: unexpected time type");
        }
    }
 
private:
    std::chrono::microseconds m_start_t{};
 
    const std::string m_prefix{};
 
    const std::string m_title{};
 
    const BCLog::LogFlags m_log_category{};
};
 
} // namespace BCLog
 
 
#define LOG_TIME_MICROS_WITH_CATEGORY(end_msg, log_category) \
    BCLog::Timer<std::chrono::microseconds> PASTE2(logging_timer, __COUNTER__)(__func__, end_msg, log_category)
#define LOG_TIME_MILLIS_WITH_CATEGORY(end_msg, log_category) \
    BCLog::Timer<std::chrono::milliseconds> PASTE2(logging_timer, __COUNTER__)(__func__, end_msg, log_category)
#define LOG_TIME_SECONDS(end_msg) \
    BCLog::Timer<std::chrono::seconds> PASTE2(logging_timer, __COUNTER__)(__func__, end_msg)
 
 
#endif // BITCOIN_LOGGING_TIMER_H