Logger class

#pragma once
#include <string>
#include <deque>
#include "pthread.h"
enum Level
{
    DEBUG = 1,
    INFO = 2,
    WARNING = 4,
    ERROR = 8
};

class Logger : public ThreadWrapper
{
public:
    Logger(int fileNum, int fileSize);
    ~Logger();
    void WriteLog(Level level, char *fmt, ...);
    virtual void Svc();
private:
    char* m_logStr;
    std::deque<std::string> m_logFileNameVec;
    int m_totalSize;

    int m_logLevel;
    pthread_mutex_t* m_mutex;
    pthread_cond_t*  m_cond;

    int m_fileSize;
    int m_fileNum;
    bool m_firstLog;
    tm* m_startTime;
};

Logger::Logger(int fileNum, int fileSize, int logLevel)
    :m_totalSize(0), m_logLevel(logLevel), m_fileSize(fileSize), m_fileNum(fileNum), m_firstLog(true)
{
    m_logStr = new char[fileSize * 1.5];
    memset(m_logStr, 0, sizeof(m_logStr));
    pthread_mutex_init(m_mutex);
    pthread_cond_init(m_cond);
}

Logger::~Logger()
{
    if (m_logStr)
    {
        delete[] m_logStr;
        m_logStr = 0;
    }
    pthread_mutex_destroy(m_mutex);
    pthread_cond_destroy(m_cond);
}
void Logger::WriteLog(Level level, char *fmt, ...)
{
    pthread_mutex_lock(m_mutex);
    va_list args;
    va_start (args, fmt);

    m_totalSize += _vsnprintf(m_logStr + m_totalSize, fmt, args);
    va_end (args);

    if (m_firstLog)
    {
        time_t* t;
        time(t);
        m_startTime = localtime(t);
        m_firstLog = false;
    }
    if (m_totalSize > m_fileSize)
    {
        pthread_cond_signal(m_cond);
    }
    pthread_mutex_unlock(m_mutex);
}

void Logger::Svc()
{
    pthread_mutex_lock(m_mutex);
    pthread_cond_wait(m_cond, m_mutex);

    time_t* t;
    time(t);
    tm* curTime = localtime(t);
    char fileName[50];
    int n = strftime(fileName, 50,"%F %H:%M:%S-", m_startTime);  
    n += strftime(fileName + n, 50 - n,","%F %H:%M:%S", curTime);
    fileName[n] = 0;
    m_logFileNameVec.push_back(fileName);
    if (m_logFileNameVec.size() > m_fileNum)
    {
        string delFileName = m_logFileNameVec[0];
        m_logFileNameVec.pop_front();
        unlink(delFileName);
    }

    FILE* outFile;
    outFile = fopen(fileName, "w");
    fwrite(m_logStr, m_totalSize, sizeof(char), outFile);
    fclose(outFile);
   

    m_totalSize = 0;
    m_firstLog = true;
    delete[] m_logStr;
    m_logStr = new char[m_fileSize * 1.5];
    memset(m_logStr, 0, sizeof(m_logStr));

    pthread_mutex_unlock(m_mutex);
}

 

此Logger类的作用：

可以通过构造函数指定日志文件的数量和每个文件的大小，文件名以对应日志文件中记录的起始和终止时间命名，适合需长期运行的服务器程序使用。

优点：适用于多线程环境，执行效率高（文件内容先缓存，直到用户手动flush或达到预设的大小时才一次写出到文件）

缺点：文件数目只对当前进程有效，当进程频繁重启时，对之前已经存在的文件不作统计，会导致日志文件不断增多。