QDir::removeRecursively() fails even on empty folder

[frank.quebec]

Greetings,

I am on Qt 5.4 built with MSVC 2012 (11.0)
Our app creates temp directories with files in it.
I am writing the cleanup function.
qDir->removeRecursively() fails all the time.
I tried running app as administrator on Windows 7.
I tried erasing all files in the directory and closing all explorers accessing the folder : still returns false.
What is wrong with removeRecursively() ?
Is there a GetLastError() thing to get more info?
BTW the temp dirs were created inside the temp folder obtained with QDir::tempPath();, for example: C:/Users/Frank/AppData/Local/Temp/GreatAppName_sectionXYZ/checksum_a4fe13430f4a23679eca887664f9d565/
In this code it would try to clean the folder "checksum_a4fe13430f4a23679eca887664f9d565"

QDir filenameQDir(dirName);
QFileInfoList multipleVersionsList = filenameQDir.entryInfoList(QDir::Dirs | QDir::NoDotAndDotDot, QDir::Time);

// The first two ones are the most recent, keep them
if (multipleVersionsList.size() > 2)
{
	for(int i=2; i<multipleVersionsList.size(); i++)
	{
		qDebug() << "   " << multipleVersionsList.at(i).absoluteFilePath() << multipleVersionsList.at(i).lastModified();
		QDir cleanupDir(multipleVersionsList.at(i).absoluteFilePath());
		if (cleanupDir.removeRecursively())
		{
			qDebug() << "Cleaned up old app folder:" << multipleVersionsList.at(i).absoluteFilePath();
		}
		else
		{
			qDebug() << "ERROR: Failed to cleanup old app folder:" << multipleVersionsList.at(i).absoluteFilePath();
		}
	}
}

[mrjj]

Hi and welcome
I tried on win 10, Qt 5.6
it did delete it all.
it was not temp folder, though.

[frank.quebec]

I found out what the problem was !
Files and folders had "read-only" attribute.
I had to remove attribute on both files and folder before being able to programmatically erase the directory recursively. I first wrote a RemoveDirRecursive() that is more powerful than the Qt's version since it removes read-only attributes. Then I simplified by just writing a RemoveReadOnlyAttributeRecursive() function. Calling this before QDir::removeRecursively() is what I will use as solution. I am attaching the function I wrote as reference. I am going to try on OSX to see if similar behavior is needed:

/* Usage :
QString directoryToRemove = "c:/my/super/awesome/directory";
RemoveReadOnlyAttributeRecursive(directoryToRemove)
QDir qDir(directoryToRemove);
qDir.removeRecursively();
*/
static bool RemoveReadOnlyAttributeRecursive(const QString& directory)
{
   int failures = 0;
   QDirIterator it(directory, QDirIterator::NoIteratorFlags);
   while (it.hasNext())
   {
      QString fileName = it.next();
      if (fileName.endsWith("/.") || fileName.endsWith("/.."))
          continue;

      QFileInfo fileInfo(fileName);
      if (fileInfo.isDir())
      {
         if (!RemoveReadOnlyAttributeRecursive(fileName))
         {
            qDebug() << "ERROR: Failed to RemoveReadOnlyAttributeRecursive() " << fileName;
            failures++;
         }
      }
      else
      {
#ifdef Q_OS_WIN
         wchar_t* fileNamePtr = (wchar_t*)fileName.utf16();
         if (!SetFileAttributes(fileNamePtr, GetFileAttributes(fileNamePtr) & ~FILE_ATTRIBUTE_READONLY))
         {
            failures++;
         }
#endif
      }
   }

#ifdef Q_OS_WIN
   wchar_t* directoryPtr = (wchar_t*)directory.utf16();
   if (!SetFileAttributes(directoryPtr, GetFileAttributes(directoryPtr) & ~FILE_ATTRIBUTE_READONLY))
   {
      failures++;
   }
#endif

   return failures == 0 ? true : false;
}

.
And the one I wrote first but will end up not using:

static bool RemoveDirRecursive(const QString& directory)
{
    int failures = 0;
    QDirIterator it(directory, QDirIterator::NoIteratorFlags);
    while (it.hasNext())
    {
        QString fileName = it.next();
        if (fileName.endsWith("/.") || fileName.endsWith("/.."))
            continue;

        QFileInfo fileInfo(fileName);
        if (fileInfo.isDir())
        {
            if (!RemoveDirRecursive(fileName))
            {
                qDebug() << "ERROR: Failed to RemoveDirRecursive() " << fileName;
                failures++;
            }
        }
        else
        {
            if (!QFile::remove(fileName))
            {
                qDebug() << "ERROR: Failed to QFile::remove() " << fileName;
#ifdef Q_OS_WIN
                wchar_t* fileNamePtr = (wchar_t*)fileName.utf16();
                SetFileAttributes(fileNamePtr, GetFileAttributes(fileNamePtr) & ~FILE_ATTRIBUTE_READONLY);
                if (!::DeleteFile(fileNamePtr))
                {
                    DWORD lastError = ::GetLastError();
                    qDebug() << "ERROR: GetLastError: " << lastError;
                    failures++;
                }
                else
                {
                    qDebug() << "Success on second try with windows API " << fileName;
                }
#else
                failures++;
#endif
            }
        }
    }

    QDir qDir;
    if(!qDir.remove(directory))
    {
        qDebug() << "ERROR: Failed to qDir.remove() " << directory;
#ifdef Q_OS_WIN
        wchar_t* directoryPtr = (wchar_t*)directory.utf16();
        SetFileAttributes(directoryPtr, GetFileAttributes(directoryPtr) & ~FILE_ATTRIBUTE_READONLY);
        if (!::RemoveDirectory(directoryPtr))
        {
           DWORD lastError = ::GetLastError();
           qDebug() << "ERROR: GetLastError: " << lastError;
           failures++;
        }
        else
        {
           qDebug() << "Success on second try delete folder with windows API " << directory;
        }
#else
        failures++;
#endif
    }
    else
    {
        qDebug() << "Success qDir.remove " << directory;
    }

    return failures == 0 ? true : false;
}