C++日志

#ifndef TRACE_LOG_H
#define TRACE_LOG_H

#include <string>
#include <fstream>

#define LOG_INFO(...) {TraceLog::GetInst().Write("[INFO]", \
    TraceLog::GetInst().Format("[%s][%s:%d]", __func__, __FILE__, __LINE__), \
    TraceLog::GetInst().Format(__VA_ARGS__) \
    );}

#define LOG_WARN(...) {TraceLog::GetInst().Write("[WARN]", \
    TraceLog::GetInst().Format("[%s][%s:%d]", __func__, __FILE__, __LINE__), \
    TraceLog::GetInst().Format(__VA_ARGS__) \
    );}

#define LOG_ERROR(...) {TraceLog::GetInst().Write("[ERROR]", \
    TraceLog::GetInst().Format("[%s][%s:%d]", __func__, __FILE__, __LINE__), \
    TraceLog::GetInst().Format(__VA_ARGS__) \
    );}

#define LOG_DEBUG(...) {TraceLog::GetInst().Write("[DEBUG]", \
    TraceLog::GetInst().Format("[%s][%s:%d]", __func__, __FILE__, __LINE__), \
    TraceLog::GetInst().Format(__VA_ARGS__) \
    );}

class TraceLog
{
public:
    static TraceLog& GetInst();
    TraceLog(const TraceLog& log) = delete;
    void Open(const std::string& path);
    void Close();
    void Write(const std::string& flag, const std::string& pos, const std::string& msg);
    std::string Format(const char* fmt, ...);
private:
    TraceLog() = default;
    std::ofstream ofs_;

};
#endif

#include <stdio.h>
#include <stdarg.h>
#include <string>
#include <fstream>
#include <ctime>
#include "TraceLog.h"
using namespace std;


TraceLog& TraceLog::GetInst()
{
    static TraceLog log;
    return log;
}

void TraceLog::Open(const std::string& path)
{
    ofs_.open(path, ifstream::out);
}

void TraceLog::Close()
{
    if (ofs_.is_open()) {
        ofs_.close();
    }
}

void TraceLog::Write(const std::string& flag, const std::string& pos, const std::string& msg)
{
    if (ofs_.is_open()) {
        time_t now = time(0);
        tm t;
        localtime_s(&t, &now);
        char buf[20] = { 0 };
        sprintf_s(buf,
            sizeof(buf),
            "[%04d%02d%02d %02d:%02d:%02d]", 
            1900 + t.tm_year,
            1 + t.tm_mon,
            t.tm_mday,
            t.tm_hour,
            t.tm_min,
            t.tm_sec);
        ofs_ << flag << buf<< pos << msg << "\n";
    }
}

string TraceLog::Format(const char* fmt, ...)
{
    char buf[1024] = { 0 };
    va_list aptr;
    va_start(aptr, fmt);
    vsprintf_s(buf, sizeof(buf), fmt, aptr);
    va_end(aptr);
    return buf;
}