VC++文件监控 ReadDirectoryChangesW

转自：http://www.cnblogs.com/mumuli/p/4364386.html

#include 
#include 
#include 

#include 

char* WideCharToMultiByte(LPCTSTR widestr)
{
    int num = WideCharToMultiByte(CP_OEMCP,NULL,widestr,-1,NULL,0,NULL,FALSE);
    char *pchar = new char[num];
    WideCharToMultiByte (CP_OEMCP,NULL,widestr,-1,pchar,num,NULL,FALSE);
    return pchar;
}

bool IsDirectory(const LPTSTR & strPath)
{
    DWORD dwAttrib    = GetFileAttributes( strPath );
    return static_cast( ( dwAttrib != 0xffffffff 
        &&    (dwAttrib & FILE_ATTRIBUTE_DIRECTORY)) );
}

int main()
{
    HANDLE hDir;
    BYTE*  pBuffer = (LPBYTE)new CHAR[4096];
    DWORD  dwBufferSize;
    LPTSTR lpPath = _T("D:\\同步目录\\");
    WCHAR  szFileName[MAX_PATH];
    char*  szFilePath;

    PFILE_NOTIFY_INFORMATION pNotify = (PFILE_NOTIFY_INFORMATION)pBuffer;

    hDir = CreateFile( lpPath, FILE_LIST_DIRECTORY,
        FILE_SHARE_READ | 
        FILE_SHARE_WRITE | 
        FILE_SHARE_DELETE, NULL, 
        OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | 
        FILE_FLAG_OVERLAPPED, NULL);
    if (hDir == INVALID_HANDLE_VALUE)
    {
        printf("INVALID_HANDLE_VALUE");
        return 0;
    }

    while (TRUE)
    {
        if(ReadDirectoryChangesW(hDir, 
            pBuffer, 
            4096, 
            TRUE, 
            FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME | FILE_NOTIFY_CHANGE_LAST_WRITE, 
            &dwBufferSize, 
            NULL, 
            NULL))
        {
            memset(szFileName, 0, MAX_PATH);
            memcpy(szFileName, lpPath, _tcslen(lpPath) * sizeof(WCHAR));
            memcpy(szFileName + _tcslen(lpPath), pNotify->FileName, pNotify->FileNameLength);
            szFilePath = WideCharToMultiByte(szFileName);

            switch(pNotify->Action)
            {
            case FILE_ACTION_ADDED:
                if (IsDirectory(szFileName))
                {
                    printf("Directory %s added.\n", szFilePath);
                }
                else
                {
                    printf("File %s added.\n", szFilePath);
                }
                break;
            case FILE_ACTION_REMOVED:
                if (IsDirectory(szFileName))
                {
                    printf("Directory %s removed.\n", szFilePath);
                }
                else
                {
                    printf("File %s removed.\n", szFilePath);
                }
                break;
            case FILE_ACTION_MODIFIED:
                if (!IsDirectory(szFileName))
                {
                    printf("File %s modified.\n", szFilePath);
                }
                break;
            case FILE_ACTION_RENAMED_OLD_NAME:
                if (pNotify && pNotify->NextEntryOffset != 0UL)
                {
                    PFILE_NOTIFY_INFORMATION pNext = (PFILE_NOTIFY_INFORMATION) ((LPBYTE)pNotify + pNotify->NextEntryOffset);
                    assert((DWORD)((BYTE*)pNext - pBuffer) < dwBufferSize);
                    {
                        WCHAR  szFileName2[MAX_PATH];
                        char*  szFilePath2;
                        memset(szFileName2, 0, MAX_PATH);
                        memcpy(szFileName2, lpPath, _tcslen(lpPath) * sizeof(WCHAR));
                        memcpy(szFileName2 + _tcslen(lpPath), pNext->FileName, pNext->FileNameLength);
                        szFilePath2 = WideCharToMultiByte(szFileName2);
                        if (IsDirectory(szFileName2))
                        {
                            printf("Directory name changed from %s to %s.\n", szFilePath, szFilePath2);
                        }
                        else
                        {
                            printf("File name changed from %s to %s.\n", szFilePath, szFilePath2);
                        }
                    }
                }
                break;
            case FILE_ACTION_RENAMED_NEW_NAME:
                printf("FILE_ACTION_RENAMED_NEW_NAME.\n");
                break;
            default:
                break;
            }
        }
    }
}

关于ReadDirectoryChangesW的详细介绍可以查看
https://msdn.microsoft.com/en-us/library/windows/desktop/aa365465(v=vs.85).aspx