C++ ofstream日志轮转实现方法

#include <fstream>
#include <iostream>
#include <string>
void writeLog(const std::string& message) {
std::ofstream logFile("app.log", std::ios::app);
if (logFile.is_open()) {
logFile << message << "\n";
logFile.close();
} else {
std::cerr << "无法打开日志文件！\n";
}
}

#include <filesystem>
#include <iostream>
bool shouldRotate(const std::string& filename, size_t maxSize) {
if (!std::filesystem::exists(filename)) return false;
return std::filesystem::file_size(filename) >= maxSize;
}
void rotateLog(const std::string& filename) {
if (std::filesystem::exists(filename)) {
std::string newname = filename + ".1";
if (std::filesystem::exists(newname)) {
std::filesystem::remove(newname);
}
std::filesystem::rename(filename, newname);
}
}

void writeLogWithRotation(const std::string& message, 
                          const std::string& filename = "app.log",
                          size_t maxSize = 1024 * 1024) { // 1MB
    if (shouldRotate(filename, maxSize)) {
        rotateLog(filename);
    }
    std::ofstream logFile(filename, std::ios::app);
    if (logFile.is_open()) {
        logFile << message << "\n";
        logFile.close();
    }
}

#include <chrono>
#include <sstream>
std::string getCurrentDate() {
auto now = std::chrono::system_clock::now();
auto time_t = std::chrono::system_clock::to_time_t(now);
std::tm tm = *std::localtime(&time_t);
std::ostringstream oss;
oss << (tm.tm_year + 1900)
<< "-" << (tm.tm_mon + 1)
<< "-" << tm.tm_mday;
return oss.str();
}
void writeDailyLog(const std::string& message) {
std::string filename = "log_" + getCurrentDate() + ".txt";
std::ofstream logFile(filename, std::ios::app);
if (logFile.is_open()) {
logFile << message << "\n";
logFile.close();
}
}