前言
个人觉得开发中比较重要的一点就是“不要重复发明轮子”，现在国外、国内开源软件遍地开花，尤其是Google，开源了一系列性能、架构特别好的代码，如果能够用开源的应该尽量避免自己造轮子。那么为什么不用log4plus呢？在这里我需要的是一个简单实用、轻巧的日志记录程序，log4plus对我有点臃肿，所以才自己花店时间写了一个简单的日志记录类。
日志类实现
刚开始想的是为了避免大量的读写程序影响性能，可以保存一个大的缓存，每次写日志就往缓存中追加数据。缓存满了后，就把缓存数据写入文件中并清空缓存。这个优点很明显：I/O操作是很耗时的，写日志太过频繁，缺点：一旦日志程序异常退出，前面写的日志可能流失。那么，对应的另一种方法就是：每次写日志就打开文件写入数据，写完关闭文件，频繁操作I/O，对于性能没那么高要求的也还好。
然后就是多个线程间互斥的设置，在同一时间对一个文件操作的当然只能有一个文件。Windows上线程同步方法：临界区、事件、信号量，我这里用的是临界区。
日志记录程序实现
多个进程公用一个日志记录程序写日志，因此日志程序必须相当稳定，还要处理进程间同步的问题。我使用的是发送WM_COPYDATA消息，日志进程的消息循环会对所有进程的日志消息放入消息队列（先入先出），无需我们去处理互斥。消息循环接收到消息后，把日志数据拷贝到内存中，然后将这个数据发送到日志记录线程中。所有的日志都在一个单独的工作线程中写入文件，该线程也维护着自己的一个消息循环，处理窗口消息接收WM_COPYDATA后发送来的日志数据。同样的道理，消息循环已经为我们维护了先进先出的数据结构，我们不用考虑互斥加锁的问题，一个接着一个的写入文件就OK了。
日志类代码
/********************************************
*一个简单的日志记录类
*2015年7月28日
*Jelin
*mailto://jelinyao@163.com
*/
#pragma once
#include "../Lock.h"
//文件最大4M
static const int g_nMaxSize = 1024*1024*4;
class CLog
{
public:
static CLog* Instance()
{
static CLog log;
return &log;
}
bool WriteLog(const char* lpLog);
bool WriteLog(const wchar_t* lpLog);
bool WriteLog(const char* lpFile, long lLine, const char* lpLog);
bool WriteLog(const char* lpFile, long lLine, const wchar_t* lpLog);
bool WriteJoinLog(const wchar_t* lpText, const wchar_t* lpLog);
bool WriteJoinLog(const char* lpFile, long lLine, const wchar_t* lpText, const wchar_t* lpLog);
protected:
CLog();
~CLog();
bool InitLogFile();
char* WcharToChar(const wchar_t* lpSource);
private:
wchar_t m_szLog[MAX_PATH];
int m_nWriteSize;
CLock m_lock;
};
#define SLOG1(x) CLog::Instance()->WriteLog(x);
#define SLOG2(x, y) CLog::Instance()->WriteJoinLog(x, y);
#define LOG1(x) CLog::Instance()->WriteLog(__FILE__, __LINE__, x)
#define LOG2(x, y) CLog::Instance()->WriteJoinLog(__FILE__, __LINE__, x, y)#include "stdafx.h"
#include "Log.h"
#include <time.h>
#include <ShlObj.h>
static const char* g_lpEnd = "\n";
CLog::CLog()
: m_nWriteSize(0)
{
InitLogFile();
}
CLog::~CLog()
{
}
bool CLog::InitLogFile()
{
wchar_t szPath[MAX_PATH]={0};
::GetModuleFileName(NULL, szPath, MAX_PATH);
for ( int i=wcslen(szPath)-1; i>=0; --i )
{
if ( szPath[i] == '\\' )
break;
szPath[i] = '\0';
}
wcscat(szPath, L"Log");
SHCreateDirectory(NULL, szPath);
SYSTEMTIME st;
GetLocalTime(&st);
swprintf(m_szLog, L"%s\\%d%02d%02d-%02d%02d%02d%03d.log", szPath, st.wYear, st.wMonth, st.wDay, st.wHour, st.wMinute, st.wSecond, st.wMilliseconds);
m_nWriteSize = 0;
return true;
}
bool CLog::WriteLog( const char* lpLog )
{
if ( NULL == lpLog )
return false;
int nLen = strlen(lpLog);
if ( 0 == nLen )
return true;
CScopeLock sl(m_lock);
if ( m_nWriteSize>=g_nMaxSize )
InitLogFile();
FILE* fp = _wfopen(m_szLog, L"a+");
if ( NULL == fp )
{
OutputDebugString(L"打开日志文件失败");
return false;
}
SYSTEMTIME st;
::GetLocalTime(&st);
char szTime[30]={0};
sprintf(szTime, "%d-%02d-%02d %02d:%02d:%02d\n", st.wYear, st.wMonth, st.wDay, st.wHour, st.wMinute, st.wSecond);
fwrite(szTime, 1, strlen(szTime), fp);
fwrite(lpLog, 1, nLen, fp);
fwrite(g_lpEnd, 1, 1, fp);
fclose(fp);
m_nWriteSize += nLen+20;
return true;
}
bool CLog::WriteLog( const wchar_t* lpLog )
{
char* pBuffer = WcharToChar(lpLog);
if ( NULL == pBuffer )
return false;
bool bRet = WriteLog(pBuffer);
free(pBuffer);
return bRet;
}
bool CLog::WriteLog( const char* lpFile, long lLine, const char* lpLog )
{
if ( NULL == lpLog )
return false;
int nLen = strlen(lpLog);
if ( 0 == nLen )
return true;
CScopeLock sl(m_lock);
if ( m_nWriteSize>=g_nMaxSize )
InitLogFile();
FILE* fp = _wfopen(m_szLog, L"a+");
if ( NULL == fp )
{
OutputDebugString(L"打开日志文件失败");
return false;
}
SYSTEMTIME st;
::GetLocalTime(&st);
char szTime[30]={0};
sprintf(szTime, "%d-%02d-%02d %02d:%02d:%02d\n", st.wYear, st.wMonth, st.wDay, st.wHour, st.wMinute, st.wSecond);
fwrite(szTime, 1, strlen(szTime), fp);
if ( NULL != lpFile )
fwrite(lpFile, 1, strlen(lpFile), fp);
char szLine[30];
sprintf_s(szLine, " line=%ld：", lLine);
fwrite(szLine, 1, strlen(szLine), fp);
fwrite(lpLog, 1, nLen, fp);
fwrite(g_lpEnd, 1, 1, fp);
fclose(fp);
m_nWriteSize += nLen+20;
return true;
}
bool CLog::WriteLog( const char* lpFile, long lLine, const wchar_t* lpLog )
{
char* lpBuffer = WcharToChar(lpLog);
if ( NULL == lpBuffer )
return false;
bool bRet = WriteLog(lpFile, lLine, lpBuffer);
free(lpBuffer);
return bRet;
}
char* CLog::WcharToChar( const wchar_t* lpSource )
{
if ( NULL == lpSource )
return NULL;
int nLen = wcslen(lpSource);
if ( 0 == nLen )
return NULL;
int nNeedSize = WideCharToMultiByte(CP_ACP, 0, lpSource, nLen, NULL, 0, NULL, NULL);
if ( 0 == nNeedSize )
return NULL;
char* pBuffer = (char*)malloc(sizeof(char)*(nNeedSize+1));
if ( NULL == pBuffer )
return NULL;
WideCharToMultiByte(CP_ACP, 0, lpSource, nLen, pBuffer, nNeedSize, NULL, NULL);
pBuffer[nNeedSize] = '\0';
return pBuffer;
}
bool CLog::WriteJoinLog( const wchar_t* lpText, const wchar_t* lpLog )
{
if ( NULL == lpText || NULL == lpLog )
return false;
int nTextLen = wcslen(lpText);
int nLogLen = wcslen(lpLog);
wchar_t* lpBuffer = (wchar_t*)malloc(sizeof(wchar_t)*(nTextLen+nLogLen+1));
wcscpy(lpBuffer, lpText);
wcscpy(lpBuffer+nTextLen, lpLog);
lpBuffer[nTextLen+nLogLen] = '\0';
bool bRet = WriteLog(lpBuffer);
free(lpBuffer);
return bRet;
}
bool CLog::WriteJoinLog( const char* lpFile, long lLine, const wchar_t* lpText, const wchar_t* lpLog )
{
if ( NULL == lpFile || NULL == lpText || NULL == lpLog )
return false;
int nTextLen = wcslen(lpText);
int nLogLen = wcslen(lpLog);
wchar_t* lpBuffer = (wchar_t*)malloc(sizeof(wchar_t)*(nTextLen+nLogLen+1));
wcscpy(lpBuffer, lpText);
wcscpy(lpBuffer+nTextLen, lpLog);
lpBuffer[nTextLen+nLogLen] = '\0';
bool bRet = WriteLog(lpFile, lLine, lpBuffer);
free(lpBuffer);
return bRet;
}
日志程序代码(win32程序)
// Logger.cpp : 定义应用程序的入口点。
//
#include "stdafx.h"
#include "Logger.h"
#include <atlstr.h>
enum{
WM_MSG_LOGGER = WM_USER + 200,
};
// 全局变量:
HINSTANCE hInst;
HWND g_hMainWnd = NULL;
HWND g_hServerWnd = NULL;
HANDLE g_hLogTh = NULL;
UINT g_dwLogTid = 0;
// 此代码模块中包含的函数的前向声明:
HWND InitInstance(HINSTANCE);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
UINT __stdcall LogThread(void* lpParam);
int APIENTRY _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)
{
try
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
if ( wcslen(lpCmdLine) == 0 )
{
TRACEW(L"参数为空\n");
return 0;
}
wstring strCmd(lpCmdLine);
string strJson = U2A(lpCmdLine);
Json::Reader r;
Json::Value vRoot;
if ( !r.parse(strJson, vRoot) )
{
TRACEW(L"参数格式不正确，解析失败\n");
return 0;
}
g_hServerWnd = (HWND)vRoot["wnd"].asInt();
g_hMainWnd = InitInstance (hInstance);
if ( NULL == g_hMainWnd )
{
TRACEW(L"创建消息窗口失败\n");
return 0;
}
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
catch(std::exception e)
{
TRACEA("捕获到异常信息：%s\n", e.what());
}
catch(...)
{
TRACEW(L"捕获到未知异常");
}
return 0;
}
HWND InitInstance(HINSTANCE hInstance)
{
static const wchar_t kWndClass[] = L"ClientMessageWindow";
WNDCLASSEX wc = {0};
wc.cbSize = sizeof(wc);
wc.lpfnWndProc = WndProc;
wc.hInstance = hInstance;
wc.lpszClassName = kWndClass;
RegisterClassEx(&wc);
return CreateWindow(kWndClass, 0, 0, 0, 0, 0, 0, HWND_MESSAGE, 0, hInstance, 0);
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_CREATE:
{
//创建日志记录线程
g_hLogTh = (HANDLE)_beginthreadex(NULL, 0, LogThread, NULL, 0, &g_dwLogTid);
//通知发送方，日志记录进程的主窗口句柄
::PostMessage(g_hServerWnd, WM_MSG_LOGGER, 0, (LPARAM)hWnd);
//设置定时器，检测发送进程的状态
::SetTimer(hWnd, 1, 3000, NULL);
break;
}
case WM_DESTROY:
PostQuitMessage(0);
break;
case WM_COPYDATA:
{
COPYDATASTRUCT* lpData = (COPYDATASTRUCT*)lParam;
/*收到日志消息后，我们需要立即处理返回，因为发送方还在阻塞等待
/*于是拷贝数据到内存中，将这个内存的地址投递到写日志的线程队列中去
/*这里会频繁的 申请\释放内存，于是用到了tcmalloc，提高性能
*/
char* pLog = (char*)malloc(lpData->cbData+1);
memcpy(pLog, lpData->lpData, lpData->cbData);
pLog[lpData->cbData] = '\0';
::PostThreadMessage(g_dwLogTid, WM_MSG_LOGGER, 0, (LPARAM)pLog);
break;
}
case WM_TIMER:
{
//检测发送方窗口是否存在，不存在说明发送日志进程已经退出
if ( !IsWindow(g_hServerWnd) )
{
::KillTimer(hWnd, 1);
//先退出日志线程
::PostThreadMessage(g_dwLogTid, WM_QUIT, 0, 0);
WaitForSingleObject(g_hLogTh, 5*1000);
CloseHandle(g_hLogTh);
//关闭主窗口，退出进程
::PostMessage(hWnd, WM_CLOSE, 0, 0);
}
break;
}
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
//日志记录线程
UINT __stdcall LogThread(void* lpParam)
{
MSG msg;
while(GetMessage(&msg, NULL, 0, 0))
{
if ( msg.message == WM_MSG_LOGGER )
{//由于消息队列替我们维护了先进先出的模型，这里写日志时无需加锁
char* pLog = (char*)msg.lParam;
SLOG1(pLog);
free(pLog);
}
}
return 0;
}还有一个
Lock.h
#pragma once
class CLock
{
public:
CLock(void) { ::InitializeCriticalSection(&m_cs); }
~CLock(void) { ::DeleteCriticalSection(&m_cs); }
void Lock() { ::EnterCriticalSection(&m_cs); }
void UnLock() { ::LeaveCriticalSection(&m_cs); }
private:
CRITICAL_SECTION m_cs;
};
class CScopeLock
{
public:
CScopeLock(CLock& lock)
:m_lock(lock)
{
m_lock.Lock();
}
~CScopeLock()
{
m_lock.UnLock();
}
private:
CLock& m_lock;
};
如何使用
#define SLOG1(x) CLog::Instance()->WriteLog(x);
#define SLOG2(x, y) CLog::Instance()->WriteJoinLog(x, y);
#define LOG1(x) CLog::Instance()->WriteLog(__FILE__, __LINE__, x)
#define LOG2(x, y) CLog::Instance()->WriteJoinLog(__FILE__, __LINE__, x, y)SLOG1(L"日志第一行");
SLOG1("日志第二行");
SLOG2("日志第三行", "第三行补充文字") 用于简单文字拼接
需要打印文件名和代码行的：
LOG1("第四行日志")
LOG2("第五行日志", "补充说明")
支持ASCII和UNICODE，当然了，UNICODE内部需要转码，如果可以选择当然还是用ASCII效率更高。
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