C++最简单的日志库

如何使用Demo示例1

simpleLogClass gLog;
...
gLog.fileMaxSize = 64 * 1024;
//gLog.outputLevel = simpleLog::LevelType::_TRACE;//默认TRACE级别输出
gLog.fileName = ws2s(GetLocalAppDataPath(L"SmartCloud")) + "\\WeesooUpdate.log";
gLog.fileOldName = ws2s(GetLocalAppDataPath(L"SmartCloud")) + "\\WeesooUpdate.old.log";
...
gLog.error("读取配置文件失败！");
...
gLog.trace("开启下载！");
...

如何使用Demo示例2

// KagulaLogger.cpp : Implementation of CKagulaLogger
#include "stdafx.h"
#include "KagulaLogger.h"

#include <comutil.h>
#pragma comment(lib, "comsuppw.lib")
// CKagulaLogger

/*
参考资料
[1]《BSTR、char*和CString转换》 http://blog.csdn.net/zeuskaaba/article/details/4082826 */
STDMETHODIMP CKagulaLogger::Init(BSTR LogFileName, BSTR backupFileName, LONG fileSizeLimit)
{
char *plogFileName = _com_util::ConvertBSTRToString(LogFileName);
char *pbackupFileName = _com_util::ConvertBSTRToString(backupFileName);

//simpleLogClass _logger;
_logger.fileMaxSize = fileSizeLimit;
_logger.fileName = plogFileName;
_logger.fileOldName = pbackupFileName;

delete plogFileName;
delete pbackupFileName;

return S_OK;
}

STDMETHODIMP CKagulaLogger::Trace(BSTR msg)
{
char *p = _com_util::ConvertBSTRToString(msg);
std::string strMsg = p;
delete p;

_logger.trace(strMsg);

return S_OK;
}

STDMETHODIMP CKagulaLogger::Info(BSTR msg)
{
char *p = _com_util::ConvertBSTRToString(msg);
std::string strMsg = p;
delete p;

_logger.info(strMsg);

return S_OK;
}

STDMETHODIMP CKagulaLogger::Error(BSTR msg)
{
char *p = _com_util::ConvertBSTRToString(msg);
std::string strMsg = p;
delete p;

_logger.error(strMsg);

return S_OK;
}

STDMETHODIMP CKagulaLogger::SetOutputLevel(BSTR level)
{
//使用_com_util::ConvertBSTRToString转数据类型，需要把临时指针delete掉，否则会内存泄露。
char *p =_com_util::ConvertBSTRToString(level);
string sLevel  = p;
delete p;

if (sLevel=="trace")
{
_logger.outputLevel = simpleLog::LevelType::_TRACE;
} else if (sLevel=="info")
{
_logger.outputLevel = simpleLog::LevelType::INFO;
} else if (sLevel=="error")
{
_logger.outputLevel = simpleLog::LevelType::_ERROR;
} else if (sLevel=="naught")
{
_logger.outputLevel = simpleLog::LevelType::NAUGHT;
}

return S_OK;
}

头文件清单

#ifndef _SIMPLELOG_H_
#define _SIMPLELOG_H_

/*
Title:C++ simple log
LastUpdate:kagula@2016-01-29
Revision:3
Environment:VS2010SP1
Note:using under emergency status!
History
[3]2016-01-29 [1]GCC 4.4.7 Support.
[2]2015-10-10 [1]support multi instance in the same process.
[1]2015-04-10 [1]limit log file size[2]add output level function![3]add test case
*/
#include <string>
#include <fstream>

using namespace std;

namespace simpleLog
{
namespace LevelType{//less is more important.
extern const int _TRACE;
extern const int INFO;
extern const int _ERROR;
extern const int NAUGHT; //no output
}
}

class simpleLogClass
{
public:
simpleLogClass();

void trace(std::string strTrace);
void info(std::string strInfo);
void error(std::string strInfo);

string fileName;
string fileOldName;
long fileMaxSize;
int outputLevel;
private:
void outputDebugInfo(int _outputLevel, std::string strInfo);
void limitFileSize();
long getFileSize();
void writeTime(ofstream &file);
};

#endif


实现文件清单

#include "simpleLog.h"

#include <stdio.h>

#include <boost/thread/thread.hpp>

using namespace std;

namespace simpleLog
{
namespace LevelType{//less is more important.
const int _TRACE = 90;
const int INFO = 50;
const int _ERROR = 30;
const int NAUGHT = 0; //no output
}
}

simpleLogClass::simpleLogClass()
{
fileName = "simpleLog.log";
fileOldName = "simpleLog.old.log";
fileMaxSize = 64 * 1024;//default is 64KB size.
outputLevel = simpleLog::LevelType::_TRACE;
}

long simpleLogClass::getFileSize() {
FILE * pFile;
long size;

pFile = fopen(fileName.c_str(), "rb");
if (pFile == NULL)
return 0l;

fseek(pFile, 0, SEEK_END);
size = ftell(pFile);
fclose(pFile);
return size;
}

void simpleLogClass::limitFileSize()
{
if (getFileSize() > fileMaxSize)
{
//if old name file exist, remove it.
remove(fileOldName.c_str());

//rename the current file to old name file.
rename(fileName.c_str(), fileOldName.c_str());
}
}

void simpleLogClass::writeTime(ofstream &file)
{
time_t t;
tm *lt;
t = time(NULL);
lt = localtime(&t);

file << (lt->tm_year + 1900) << "-" << (lt->tm_mon + 1) << "-" << lt->tm_mday << " ";
file << lt->tm_hour << ":" << lt->tm_min << ":" << lt->tm_sec << " ";
}

void simpleLogClass::outputDebugInfo(int _outputLevel, std::string strInfo)
{
static boost::mutex mInfo;
boost::lock_guard<boost::mutex> lock(mInfo);

limitFileSize();

std::string strLevel;
switch (_outputLevel)
{
case simpleLog::LevelType::_TRACE:
strLevel = "trace";
break;
case simpleLog::LevelType::INFO:
strLevel = "info";
break;
case simpleLog::LevelType::_ERROR:
strLevel = "error";
break;
}

std::ofstream file(fileName.c_str(), ios::app | ios::out);
writeTime(file);
file << strLevel.c_str() << " " << strInfo.c_str() << endl;
file.close();
}

void simpleLogClass::trace(std::string strTrace)
{
if (outputLevel >= simpleLog::LevelType::_TRACE)
{
outputDebugInfo(simpleLog::LevelType::_TRACE, strTrace);
}
}

void simpleLogClass::info(std::string strInfo)
{
if (outputLevel >= simpleLog::LevelType::INFO)
{
outputDebugInfo(simpleLog::LevelType::INFO, strInfo);
}
}

void simpleLogClass::error(std::string strInfo)
{
if (outputLevel >= simpleLog::LevelType::_ERROR)
{
outputDebugInfo(simpleLog::LevelType::_ERROR, strInfo);
}
}