Profiler.h

// Copyright(c) 2019 - 2020, #Momo
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// 
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// modification, are permitted provided that the following conditions are met :
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// 1. Redistributions of source code must retain the above copyright notice, this
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// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
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#pragma once

#include "Utilities/Time/Time.h"
#include "Utilities/Logger/Logger.h"
#include "Utilities/SingletonHolder/SingletonHolder.h"

#include <fstream>
#include <string>

namespace MxEngine
{
    class ProfileSession
    {
        std::ofstream stream;
        size_t entriesCount = 0;

        void WriteJsonHeader();
        void WriteJsonFooter();
    public:
        bool IsValid() const;
        size_t GetEntryCount() const;
        void StartSession(const MxString& filename);
        void WriteJsonEntry(const char* function, TimeStep begin, TimeStep delta);
        void EndSession();
    };

    using Profiler = SingletonHolder<ProfileSession>;

    class ScopeProfiler
    {
        TimeStep start;
        const char* function;
        ProfileSession& profiler;
    public:
        inline ScopeProfiler(ProfileSession& profiler, const char* function)
            : start(Time::Current()), function(function), profiler(profiler) { }

        inline ~ScopeProfiler()
        {
            TimeStep end = Time::Current();
            this->profiler.WriteJsonEntry(this->function, this->start, end - start);
        }
    };

    class ScopeTimer
    {
        TimeStep start;
        MxString function;
        std::string_view invoker;
    public:
        inline ScopeTimer(std::string_view invoker, std::string_view function)
            : start(Time::Current()), invoker(invoker), function(function.data())
        {
            Logger::Instance().Debug(this->invoker.data(), "calling " + this->function);
        }

        inline ~ScopeTimer()
        {
            TimeStep end = Time::Current();
            MxString delta = BeautifyTime(end - start);
            Logger::Instance().Debug(this->invoker.data(), this->function + " finished in " + delta);
        }
    };

// wrapper aroung ScopeProfiler
#define MAKE_SCOPE_PROFILER(function) ScopeProfiler MXENGINE_CONCAT(_profiler, __LINE__)(Profiler::Instance(), function)
// wrapper around ScopeTimer
#define MAKE_SCOPE_TIMER(invoker, function) ScopeTimer MXENGINE_CONCAT(_timer, __LINE__)(invoker, function)
}