#! /bin/sh
###
### Make fake snapshots by doing nothing at all
###
### (c) 2011 Mark Wooding
###

###----- Licensing notice ---------------------------------------------------
###
### This file is part of the distorted.org.uk backup suite.
###
### distorted-backup is free software; you can redistribute it and/or modify
### it under the terms of the GNU General Public License as published by
### the Free Software Foundation; either version 2 of the License, or
### (at your option) any later version.
###
### distorted-backup is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
### GNU General Public License for more details.
###
### You should have received a copy of the GNU General Public License along
### with distorted-backup; if not, write to the Free Software Foundation,
### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

set -e
quis=${0##*/}

###--------------------------------------------------------------------------
### Parse the command line.

## Provide help or version information.
usage="usage: $quis DEVICE [KEY=VALUE ...]"
version="$quis, version 1.0.0"
case "$#,$1" in
  0,*) echo >&2 "$usage"; exit 1 ;;
  *,-v | *,--version) echo "$version"; exit ;;
  *,-h | *,--help)
    cat <<EOF
$version
$usage

Option keys:
  op=OPERATION		\`snap' to create snapshot, or \`unsnap' to remove.
  tag=TAG		Disambiguation tag to store in filesystem.
EOF
    exit
    ;;
esac

## Scan the option keys.
dev=$1; shift
Oop=snap Otag=snap
win=t
for i in "$@"; do
  case "$i" in
    ?*=*) ;;
    *) echo >&2 "$quis: malformed option \`$i'"; exit 1 ;;
  esac
  k=${i%%=*} v=${i#*=}
  case "$k" in *.trivial) k=${k%.trivial} ;; ?*.?*) continue ;; esac
  case "$k" in
    op | tag) eval "O$k=\$v" ;;
    *) echo >&2 "$quis: unknown option \`$k'"; win=nil ;;
  esac
done
case $win in nil) exit 1 ;; esac

###--------------------------------------------------------------------------
### Take or remove the snapshot.

case "$Oop" in
  snap)
    echo "$dev"
    ;;
  unsnap)
    ;;
  *)
    echo >&2 "$quis: unknown operation \`$Oop'"
    exit 1
    ;;
esac

###----- That's all, folks --------------------------------------------------