zsh addon update check

zsh-addon-update-check.zsh

function _do-gen-update() {
  echo "Upgrading $2..."
  case "$2" in
    volt) volt self-upgrade -check ;;
    zplugin) zplugin upgrade --all ;;
    *) echo "Unknown application $2.  Moving on..." ;;
  esac
  touch "$1"
}

function gen-update-check() {
  checkfile="$HOME/.$1-update-check"
  [[ -f "$checkfile" ]] || _do-gen-update "$checkfile" "$1"
  eval $(stat -s "$checkfile")
  #printf "now: %s\nlastcheck: %s\n" $st_atime $st_mtime
  (( (st_atime - 604800) > st_mtime )) && _do-gen-update "$checkfile" "$1"
}

for p in volt zplugin; do (gen-update-check $p); done
wait
unset p