[KPhotoAlbum] Another performance issue

[Robert Krawitz]

I've determined that

DB::FileNameList ThumbnailView::ThumbnailWidget::selection(ThumbnailView::SelectionMode mode) const

is being called once per image, and each time it loops over all images
currently in the set, so it's quadratic (these lines are >>>in and
<<<out, with the incrementing number being the number of times through
the loop).

kphotoalbum.ThumbnailWidget: >>> ThumbnailWidget::Selection 1
kphotoalbum.ThumbnailWidget: <<< ThumbnailWidget::Selection 3426 0
kphotoalbum.ThumbnailWidget: >>> ThumbnailWidget::Selection 1
kphotoalbum.ThumbnailWidget: <<< ThumbnailWidget::Selection 3427 0
kphotoalbum.ThumbnailWidget: >>> ThumbnailWidget::Selection 1
kphotoalbum.ThumbnailWidget: <<< ThumbnailWidget::Selection 3428 0
kphotoalbum.ThumbnailWidget: >>> ThumbnailWidget::Selection 1
kphotoalbum.ThumbnailWidget: <<< ThumbnailWidget::Selection 3429 0
kphotoalbum.ThumbnailWidget: >>> ThumbnailWidget::Selection 1
kphotoalbum.ThumbnailWidget: <<< ThumbnailWidget::Selection 3430 0
kphotoalbum.ThumbnailWidget: >>> ThumbnailWidget::Selection 1
kphotoalbum.ThumbnailWidget: <<< ThumbnailWidget::Selection 3431 0

-- 
Robert Krawitz                                     <rlk at alum.mit.edu>

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