Find if file exists in QFileSystemModel.

[tokafr]

Hi
I want to to create a Folder with mkdir of QFileSystemModel. But I want to create with name "New Folder" and if "New Folder" already exists create "New Folder(1)". So Firstly I want to find out it "New Folder" already exists. How can I find it?
for now I do

int count = 0;
QModelIndex fileIndex = FileModel_ -> index(nameToCheck);

 while (FileModel_ -> fileInfo(fileIndex).exists())
    {
      nameToCheck = name + "(" + (++count) + ")";
      fileIndex = FileModel_ -> index(nameToCheck);
    }

    FileModel_ -> mkdir(parentDir, nameToCheck);

Where FileModel_ is an object of QFileSystemModel.
thanks