Question

Basically I have a directory in which I want X elements at most to be stored, and after that every files added must trigger the removal of the oldest stored element. So I thought to order them by Time in QFileInfoList but sadly this becomes system time dependent (if the user turns the clock by Y hours the latest files added will be considered th oldest and thus removed). This is what I've written so far with the problem of system time in it:

void namespace::cleanStationLogoDir()
{
    QDir dir(DIR);
    if(!dir.exists())
    {
        //Create directory
        if(dir.mkpath(DIR))
        {
            //Ok result
        }
        else
        {
            qDebug() << "Unable to create dir.";
        }
    }

    QFileInfoList files = dir.entryInfoList(QDir::Files | QDir::NoDotAndDotDot, QDir::Time);
    qDebug() << "files size: " << files.size();

    while(files.size() > X)
    {
        qDebug() << "Removed last element" << files.last().filePath();
        dir.remove(files.takeLast().filePath());
        qDebug() << "files size: " << logo_files.size();
    }
}

Do you know any other way to do this? I considered adding an incremental ID to the name of the files while I store them but after max_INT files this could turn out to be a roblem, or if I wrap the IDs to X elements then I'm not sure which to remove on the next file received.

Answer 1

1）您可以使用纪元时间作为文件名的一部分，而不是使用一个不会明显重置或重用的任意增量变量。

2）您可以使用QFileInfo，就像您可以将现有逻辑更改为

QFileInfoList files = dir.entryInfoList(QDir::Files | QDir::NoDotAndDotDot, QDir::Time | QDir::Reversed);
const int  MAX_NUM_FILES_TO_RETAIN = 10

for(int index = files.size(); index > MAX_NUM_FILES_TO_RETAIN; --index)
{
     const QFileInfo& info = files.at(index -1);
     QFile::remove(info.absoluteFilePath());
}

该代码将删除较旧的文件，同时保留最近的10个文件。

Deleting items in a folder after X elements, from oldest, in Qt

1 个答案: