Question

I conduct a file search and there is exception list for directories, the problem is below code recursively iterates through all files on hard drives. It works but it is slow. Therefore, I need help to optimize its performance. Thanks in advance.

CFileFind finder;

    // build a string with wildcards
    CString strWildcard(directory);
    strWildcard += _T("\\*.*");

    // start working for files
    BOOL bWorking = finder.FindFile(strWildcard);

    while (bWorking)
    {
        bWorking = finder.FindNextFile();

        if (finder.IsDots())
            continue;

        // if it's a directory, recursively search it

        if (finder.IsDirectory())
        {
            CString str = finder.GetFilePath();
            if(NULL == m_searchExceptions.Find(str)){
                _recursiveSearch(str);
            }
            else{
                continue;
            }
        }
        //basic comparison, can be replaced by strategy pattern if complicated comparsion required (e.g. REGEX)
        if(0 == finder.GetFileName().CompareNoCase(m_searchPattern)){
            if(m_currentSearchResults.Find(finder.GetFilePath()) == NULL){
                m_currentSearchResults.AddHead(finder.GetFilePath());       
            }
        }
    }

Answer 1

I don’t think you’re going to be able to optimize performance here. You’re going to be spending 80+% of your time inside FindFirstFile and FindNextFile here (windows API calls) no matter what you do in terms of optimization on your end.

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