A Log implement in Win32 C++

log.cpp

#include "stdafx.h"
#include "Cx_SeaLog.h"

#include <string>
#include <sstream>
#include <vector>
using namespace std;

#define MAX_LOGFILE_SIZE   1024*1024   // LOG文件最大为1MB


CRITICAL_SECTION Cx_SeaLog::s_csLog;   //< 日志关键区

/////////////////////////////////////////////////////////////////////////////

#define Int64ShllMod32(a, b) ((DWORDLONG)(a) << (b))

// reverse of part of transformation in InternetTimeFromTime_t
//  A filetime is the numbers of 100 ns since Jan 1, 1601, while
//a dostime is the number of seconds since Jan 1, 1970.
static void FileTimeToDosTime( FILETIME ft, DWORD* pTime_t)
{
    //dwl1970Offset is the number of ns from 1601 to 1970
    const DWORDLONG dwl1970Offset = 0x019dae9064bafa80;
	
    DWORDLONG lVal;
    
    lVal = ft.dwLowDateTime;
    lVal |= Int64ShllMod32( Int64ShllMod32( ft.dwHighDateTime, 16), 16 );
	
    *pTime_t = (DWORD)((lVal - dwl1970Offset) / 10000000);
	
    return;
}

/////////////////////////////////////////////////////////////////////////////

void Cx_SeaLog::Init()
{
	InitializeCriticalSection(&s_csLog);	
}

void Cx_SeaLog::UnInit()
{
	DeleteCriticalSection(&s_csLog);
}

Cx_SeaLog::Cx_SeaLog()
{
}

Cx_SeaLog::~Cx_SeaLog()
{
}

void Cx_SeaLog::GetCurTime(wstring& strCurTime,
						   const wstring& strFormat /* = L"\r\n%d-%02d-%02d %02d:%02d:%02d  \t"*/) const 
{
	// Write current time
	SYSTEMTIME  systime ={0};
	GetLocalTime(&systime);
	TCHAR szTime[256] = {0};
	wsprintf(szTime, strFormat.c_str(), systime.wYear, systime.wMonth, 
					systime.wDay, systime.wHour, systime.wMinute, systime.wSecond);

	strCurTime = wstring(szTime);

	return;
}

bool Cx_SeaLog::BackupLogFile(const std::wstring & strLogFile)
{
	// 以当前时间为备份文件名
	wstring strCurTime;
	GetCurTime(strCurTime);
	wstring strNewFile = strCurTime + L".txt";

	WCHAR szNewFile[MAX_PATH] = L"\0";

	::GetModuleFileName(NULL, szNewFile, MAX_PATH);
	::PathRemoveFileSpec(szNewFile);
	::PathAppend(szNewFile, L"Log");   
	::PathAppend(szNewFile, strNewFile.c_str());   

	return TRUE == ::MoveFile(strLogFile.c_str(), szNewFile);
}

// TODO: !! 代码需要整理 [Huangye 11/03/26]
void Cx_SeaLog::WriteLog(const std::wstring& strLog)
{
	EnterCriticalSection(&s_csLog);

	static TCHAR szFileName[MAX_PATH] = L"";

	if (wcscmp(szFileName, L"") == 0)
	{
		::GetModuleFileName(NULL, szFileName, MAX_PATH);
		::PathRemoveFileSpec(szFileName);
		::PathAppend(szFileName, L"Log");   
		::PathAppend(szFileName, L"Log.txt");   
	}
	
	HANDLE hFile = ::CreateFile(szFileName, GENERIC_WRITE, 0, 
									NULL, OPEN_ALWAYS, 0, NULL );
	if (hFile == INVALID_HANDLE_VALUE)
		return;

	DWORD nWrite = 0;
	
	int nSize = 0;
	if (hFile)  
	{
		nSize =  ::GetFileSize(hFile, NULL );
	}

	// 日志文件大小超过1MB
	if (nSize >= MAX_LOGFILE_SIZE)
	{
		CloseHandle(hFile);

		// 备份当前日志文件
		VERIFY(BackupLogFile(szFileName));
		
		// 重新打开文件句柄
		HANDLE hFile = ::CreateFile(szFileName, GENERIC_WRITE, 0, 
									NULL, OPEN_ALWAYS, 0, NULL );

		ASSERT(hFile != INVALID_HANDLE_VALUE);
		if (hFile == INVALID_HANDLE_VALUE)
			return;

		ASSERT(0 == ::GetFileSize(hFile, NULL ));
		nSize = 0; // 文件大小为零
	}
	
	// 首先写入UTF-16的文件头
	if (nSize == 0) 
	{
		const unsigned char LeadBytes[]  = {0xFF, 0xFE};
		::WriteFile( hFile, LeadBytes, 2, &nWrite, NULL );
		::FlushFileBuffers(hFile);
	}
	
	// 寻道到文件最后的位置
	LONG dwMoveH = 0;
	DWORD dwMoveL = 0;
	dwMoveL = ::SetFilePointer(hFile, dwMoveL, &dwMoveH, FILE_END);

	// 记录当前时间
	wstring strCurTime;
	GetCurTime(strCurTime);
	DWORD dwNumberOfBytesToWrite = strCurTime.size();

	::WriteFile( hFile, strCurTime.c_str(), 
				 dwNumberOfBytesToWrite * sizeof(WCHAR), &nWrite, NULL );
	ASSERT(dwNumberOfBytesToWrite * sizeof(WCHAR) == nWrite);

	// 写日志
	::WriteFile( hFile, strLog.c_str(), strLog.size() * sizeof(WCHAR), &nWrite, NULL );  
	ASSERT(strLog.size() * sizeof(WCHAR) == nWrite);
	::FlushFileBuffers(hFile);

	CloseHandle(hFile);

	LeaveCriticalSection(&s_csLog);
}

// strPath目录必须以"\"分隔,且最后一个字符不能为分隔符
bool Cx_SeaLog::CleanLogFile(const wstring& strPath, const int nTime /* = MAX_LOGFILE_TIME*/)
{
	UINT nCnt = 0;
	bool bFind = true;

	wstring strFindPath = strPath + L"\\*";

	// 清理日志文件时，要避免与写文件的操作冲突，需要加锁保护
	EnterCriticalSection(&s_csLog);

	WIN32_FIND_DATA finddata;
	HANDLE hFind = ::FindFirstFile(strFindPath.c_str(), &finddata);
	
	if (INVALID_HANDLE_VALUE == hFind)
	{
		return false;
	}
	
	do
	{
		// 过滤当前目录与上级目录
		if (_tcscmp(finddata.cFileName, L".") == 0
			  || _tcscmp(finddata.cFileName, L"..") == 0)
		{
			continue;
		}

		// 不处理嵌套目录 
		if((finddata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
				== FILE_ATTRIBUTE_DIRECTORY)
		{
			continue;
		}

		time_t modifiedTime;
		FileTimeToDosTime(finddata.ftLastWriteTime, (ULONG*)&modifiedTime);
		
		time_t curTime = ::time(NULL);
		
		// 日志的最后修改时间距现在超过限定时间，则删除日志文件
		// ASSERT(curTime - modifiedTime > 0);
		if (curTime - modifiedTime > MAX_LOGFILE_TIME)
		{
			wstring strFullName = strPath + L"\\" + finddata.cFileName;
			VERIFY(::DeleteFile(strFullName.c_str()));
		}
		
	} while(::FindNextFile(hFind, &finddata));


	FindClose(hFind);

	LeaveCriticalSection(&s_csLog);

	return true;
}