#!/bin/sh
#
# Copyright (C) 2015-2022 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 <https://www.gnu.org/licenses/>.
#

progname=$0

# func_exit STATUS
# exits with a given status.
# This function needs to be used, rather than 'exit', when a 'trap' handler is
# in effect that refers to $?.
func_exit ()
{
  (exit $1); exit $1
}

# func_tmpdir
# creates a temporary directory.
# Input:
# - progname                 name of this program
# Sets variable
# - tmp             pathname of freshly created temporary directory
func_tmpdir ()
{
  # Use the environment variable TMPDIR, falling back to /tmp. This allows
  # users to specify a different temporary directory, for example, if their
  # /tmp is filled up or too small.
  : ${TMPDIR=/tmp}
  {
    # Use the mktemp program if available. If not available, hide the error
    # message.
    tmp=`(umask 077 && mktemp -d "$TMPDIR/glXXXXXX") 2>/dev/null` &&
    test -n "$tmp" && test -d "$tmp"
  } ||
  {
    # Use a simple mkdir command. It is guaranteed to fail if the directory
    # already exists.  $RANDOM is bash specific and expands to empty in shells
    # other than bash, ksh and zsh.  Its use does not increase security;
    # rather, it minimizes the probability of failure in a very cluttered /tmp
    # directory.
    tmp=$TMPDIR/gl$$-$RANDOM
    (umask 077 && mkdir "$tmp")
  } ||
  {
    echo "$progname: cannot create a temporary directory in $TMPDIR" >&2
    func_exit 1
  }
}

func_tmpdir
trap 'exit_status=$?
      if test "$signal" != EXIT; then
        echo "caught signal SIG$signal" >&2
      fi
      rm -rf "$tmp"
      exit $exit_status' EXIT
for signal in HUP INT QUIT PIPE TERM; do
  trap '{ signal='$signal'; func_exit 1; }' $signal
done
signal=EXIT

sed_literal_to_basic_regex='s/\\/\\\\/g
s/\[/\\[/g
s/\^/\\^/g
s/\([.*$]\)/[\1]/g'

# Populate the cache
(cd "$GNULIB_SRCDIR" \
 && find modules -type f -print | while read modfile; do
   sed -n -e '/^Depends-on:/,/^$/p' < "$modfile" \
     | sed -e '/^Depends-on:/d' -e '/^$/d' > "$tmp/dependencies"
   dependent=$(echo $modfile | sed -e 's,modules/,,')
   dependent_regex=`echo "$dependent" | sed -e "$sed_literal_to_basic_regex"`
   if test ! -f "$tmp/cache" \
       || ! grep " $dependent_regex\$" "$tmp/cache" >/dev/null 2>&1; then
     sed -e "s,\$, $dependent," < "$tmp/dependencies" >> "$tmp/cache"
   fi
 done)

# Recursively list dependent modules
func_get_dependent ()
{
  module_regex=`echo "$1" | sed -e "$sed_literal_to_basic_regex"`
  if grep "^$module_regex " "$tmp/cache" > "$tmp/result" 2>/dev/null; then
    sed -n -e 's,.* \([^ ]*\)$,\1,p' < "$tmp/result" | while read dependent; do
      echo "$dependent"
      func_get_dependent "$dependent"
    done
  fi
}

while read module; do
  echo "$module"
  func_get_dependent "$module"
done

rm -rf "$tmp"

# Undo the effect of the previous 'trap' command. Some shellology:
# We cannot use "trap - 0 1 2 3 13 15", because Solaris sh would attempt to
# execute the command "-". "trap '' ..." is fine only for signal 0 (= normal
# exit); for the others we need to call 'exit' explicitly. The value of $? is
# 128 + signal number and is set before the trap-registered command is run.
trap '' 0
trap 'func_exit $?' 1 2 3 13 15

exit 0