#! /bin/sh
# Run a test script of the coreutils test scripts, picking up the right
# interpreter (i.e., perl or the shell) and the right flags for it (e.g.,
# perl '-T' flag for perl scripts that must run in tainted mode).
#
# Copyright (C) 2011-2012 Free Software Foundation, Inc.
#
# This program 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 3 of the License, or
# (at your option) any later version.
#
# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
#

# ---------------------------------- #
#  Readonly variables and functions  #
# ---------------------------------- #

# Help to avoid typo-related bugs.
set -u

me=shell-or-perl

fatal_ ()
{
  echo "$me: $*" >&2
  # Exit with status '99' to inform the testsuite harness that an
  # hard error occurred.
  exit 99
}

print_help_ ()
{
  cat <<EOH
Usage: $me [--help] [--srcdir DIR] [--shell SHELL-CMD] [--perl PERL-CMD]
       [--test-name NAME-WITHOUT-VPATH] TEST-SCRIPT [ARGS..]
EOH
}

# ---------------- #
#  Option parsing  #
# ---------------- #

assign_optarg_to_var='
  test $# -gt 1 || fatal_ "option '\''$1'\'' requires an argument"
  eval "$var=\$2"
  shift'

srcdir=${srcdir-.}
cu_PERL=${PERL-perl}
cu_SHELL=/bin/sh # Getting $SHELL from the environment is dangerous.
test_name=
while test $# -gt 0; do
  var=
  case $1 in
    --help) print_help_; exit $?;;
    --shell) var=cu_SHELL;;
    --perl) var=cu_PERL;;
    --srcdir) var=srcdir;;
    --test-name) var=test_name;;
    --) shift; break;;
    -*) fatal_ "unknown option '$1'";;
    *) break;;
  esac
  test -z "$var" || eval "$assign_optarg_to_var"
  shift
done

unset assign_optarg_to_var var

case $# in
  0) fatal_ "missing argument";;
  *) test_script=$1; shift;;
esac

test -z "$test_name" && test_name=$test_script

# --------------------- #
#  Run the test script  #
# --------------------- #

test -f "$test_script" && test -r "$test_script" \
  || fatal_ "test script '$test_script' does not exist, or isn't readable"

read shebang_line < "$test_script" \
  || fatal_ "cannot read from the test script '$test_script'"

case $shebang_line in
'#!/usr/bin/perl'*)
  # The test is a perl script.
  if $cu_PERL -e 'use warnings' > /dev/null 2>&1; then
    # Perl is available, see if we must run the test with taint
    # mode on or not.
    case $shebang_line in *\ -T*) T_=T;; *) T_=;; esac
    # Now run it.
    exec $cu_PERL -w$T_ -I"$srcdir" -MCoreutils -MCuSkip \
                  -M"CuTmpdir qw($test_name)" \
                  -- "$test_script" ${1+"$@"}
  else
    # Perl is not available, skip the test.
    echo "$test_name: skip: no usable version of Perl found"
    exit 77
  fi
  ;;
*)
  # Assume the test is a shell script.
  exec $cu_SHELL "$test_script" ${1+"$@"}
esac

# ------------- #
#  Not reached  #
# ------------- #

fatal_ "dead code reached"