1diff_cmd () {
   2        empty_file=
   3        # p4merge does not like /dev/null
   5        if test "/dev/null" = "$LOCAL"
   6        then
   7                LOCAL="$(create_empty_file)"
   8        fi
   9        if test "/dev/null" = "$REMOTE"
  10        then
  11                REMOTE="$(create_empty_file)"
  12        fi
  13        "$merge_tool_path" "$LOCAL" "$REMOTE"
  15        if test -n "$empty_file"
  17        then
  18                rm -f "$empty_file"
  19        fi
  20}
  21merge_cmd () {
  23        touch "$BACKUP"
  24        $base_present || >"$BASE"
  25        "$merge_tool_path" "$BASE" "$LOCAL" "$REMOTE" "$MERGED"
  26        check_unchanged
  27}
  28create_empty_file () {
  30        empty_file="${TMPDIR:-/tmp}/git-difftool-p4merge-empty-file.$$"
  31        >"$empty_file"
  32        printf "$empty_file"
  34}