post_install() {
  echo "update desktop mime database..."
  update-mime-database usr/share/mime 1> /dev/null
  update-desktop-database -q
}
post_upgrade() {
  post_install $1
}

post_remove() {
  echo "update desktop mime database..."
  update-mime-database usr/share/mime 1> /dev/null
  update-desktop-database -q
}