#! @SHELL@
# web2c-sh: shell script to invoke ${srcdir}/web2c/convert.
#
#   Copyright (C) 2009, 2012 Peter Breitenlohner <tex-live@tug.org>
#
#   This file is free software; the copyright holder
#   gives unlimited permission to copy and/or distribute it,
#   with or without modifications, as long as this notice is preserved.
#
# Convert creates several files, e.g., FOO.c and FOO.h from FOO.p.
# The naive rule
#	FOO.c FOO.h: FOO.p $(web2c_depend)
#		srcdir=$(srcdir) $(SHELL) $(srcdir)/web2c/convert FOO
# could run 'convert FOO' twice in parallel and fail.  To avoid this
# and yet recover from removal of FOO.c and/or FOO.h, we use an auxiliary
# stamp file FOO-web2c and the two rules
#	FOO.c FOO.h: FOO-web2c
#		$(SHELL) ./web2c-sh $@ FOO
#	FOO-web2c: FOO.p $(web2c_depend)
#		$(SHELL) ./web2c-sh $@ FOO
# Compare Automake manual (info Automake) 27.9: Multiple Outputs
#
srcdir=@srcdir@; export srcdir
target=$1
base=$2
stamp=$base-web2c
case $target in
  $stamp)
    # Normal build.
    rm -f $stamp.tmp
    echo timestamp >$stamp.tmp
    echo "  WEB2C   " $base
    @SHELL@ $srcdir/web2c/convert $base || exit 1
    mv -f $stamp.tmp $stamp
  ;;
  *)
    # Recover from removal of $target
    test -f $target && exit 0
    trap "rm -rf $stamp $stamp.lock" 1 2 13 15
    if mkdir $stamp.lock 2>/dev/null; then
      # Code executed by the first process.
      rm -f $stamp $stamp.tmp
      echo timestamp >$stamp.tmp
      echo "  WEB2C   " $base
      @SHELL@ $srcdir/web2c/convert $base || exit 1
      mv -f $stamp.tmp $stamp
      rmdir $stamp.lock
    else
      # Code executed by the follower processes.
      # Wait until the first process is done.
      while test -d $stamp.lock; do sleep 1; done
      # Succeed if and only if the first process succeeded.
      test -f $stamp; exit $?
    fi
  ;;
esac

exit 0
