#!/bin/sh

# erlwareSys: otp/build/beamver,v 1.1 2002/02/14 11:45:20 hal Exp $

# usage: beamver <beam_file>
#
# if there's a usable -vsn() attribute, print it and exit with status 0
# otherwise, print nothing and exit with status 1

# From the Erlang shell:
#
# 5> code:which(acca_inets).
# "/home/martin/work/otp/releases/<app>/../../acca/ebin/<app>.beam"
# 
# 8> beam_lib:version(code:which(<app>)).
# {ok,{<app>,['$Id: beamver,v 1.1.1.1 2003/06/13 21:43:21 mlogan Exp $ ']}}

# TMPFILE looks like this:
#
# io:format("hello ~p~n",
#   beam_lib:version("/home/hal/work/otp/acca/ebin/acca_inets.beam")]).

TMPFILE=/tmp/beamver.$$

# exit with failure if we can't read the file
test -f "$1" || exit 1
BEAMFILE=\"$1\"

cat > $TMPFILE <<_EOF
io:format("~p~n",
  [beam_lib:version($BEAMFILE)]).
_EOF

# beam_result is {ok,{Module_name, Beam_version} or {error,beam_lib,{Reason}}
beam_result=`erl -noshell \
  -s file eval $TMPFILE \
  -s erlang halt`

rm -f $TMPFILE

# sed regexes:
#   remove brackets and anything outside them
#   remove quotes and anything outside them
#   remove apostrophes and anything outside them
#   remove leading and trailing spaces

case $beam_result in
\{ok*)
  echo $beam_result | sed -e 's/.*\[\(.*\)].*/\1/'  \
                          -e 's/.*\"\(.*\)\".*/\1/' \
                          -e "s/.*\'\(.*\)\'.*/\1/" \
                          -e 's/ *$//' -e 's/^ *//'
  exit 0
  ;;
*)
  exit 1
  ;;
esac