如下代码中ProcessMsgLoop()的作用是什么呢？FILEMISC.H

Question

bool DeleteFolderContents(LPCTSTR szFolder, BOOL bIncludeSubFolders, LPCTSTR szFileMask, HANDLE hTerminate, BOOL bProcessMsgLoop)
{
// if the dir does not exists just return
DWORD dwAttr = GetFileAttributes(szFolder);

    if (dwAttr == 0xffffffff || !(dwAttr & FILE_ATTRIBUTE_DIRECTORY))
        return false;

    // if a file mask has been specified with subfolders we need to do 2 passes on each folder, 
    // one for the files and one for the sub folders
    int nPasses = (bIncludeSubFolders && (szFileMask && lstrlen(szFileMask))) ? 2 : 1;

    bool bResult = true;
    bool bStopped = (WaitForSingleObject(hTerminate, 0) == WAIT_OBJECT_0);

    for (int nPass = 0; !bStopped && nPass < nPasses; nPass++)
    {
        CString sSearchSpec(szFolder), sMask(szFileMask);

        if (sMask.IsEmpty() || nPass == 1) // (nPass == 1) == 2nd pass (for folders)
            sMask = "*.*";

        TerminatePath(sSearchSpec);
        sSearchSpec += sMask;

        WIN32_FIND_DATA finfo;
        HANDLE hSearch = NULL;

        if ((hSearch = FindFirstFile(sSearchSpec, &finfo)) != INVALID_HANDLE_VALUE)
        {
            do
            {
                if (bProcessMsgLoop)
                **  ProcessMsgLoop();**

                if (finfo.cFileName[0] != '.')
                {
                    CString sItem(szFolder);
                    sItem += "\\";
                    sItem += finfo.cFileName;

                    if (finfo.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
                    {
                        if (bIncludeSubFolders && (nPass == 1 || nPasses == 1))
                        {
                            if (DeleteFolderContents(sItem, TRUE, szFileMask, hTerminate, bProcessMsgLoop))
                            {
                                if (!szFileMask || !lstrlen(szFileMask))
                                    bResult = (RemoveDirectory(sItem) == TRUE);
                            }
                        }
                    }
                    else
                        bResult = (DeleteFile(sItem) == TRUE);
                }

                bStopped = (WaitForSingleObject(hTerminate, 0) == WAIT_OBJECT_0);
            } while (!bStopped && bResult && FindNextFile(hSearch, &finfo));

            FindClose(hSearch);
        }
    }

    return (!bStopped && bResult);
}

void ProcessMsgLoop()
{
    MSG msg;

    while (::PeekMessage((LPMSG)&msg, NULL, 0, 0, PM_REMOVE))
    {
        if (IsDialogMessage(msg.hwnd, (LPMSG)&msg))
        {
            // do nothing - its already been done
        }
        else
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }
}

Answer 1

ProcessMsgLoop的作用是DeleteFolderContents在界面线程操作的时候预防界面卡死，不过这是不好的风格，违背了函数功能单一原则，也不能很好的
解决界面卡住，但是开一个线程去操作deletefolder才能彻底解决界面卡死