# Check how to create a tarball.                            -*- Autoconf -*-

# Copyright (C) 2004-2012 Free Software Foundation, Inc.
#
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.

# _AM_PROG_TAR(FORMAT)
# --------------------
# Check how to create a tarball in format FORMAT.
# FORMAT should be one of 'v7', 'ustar', or 'pax'.
#
# Substitute a variable $(am__tar) that is a command
# writing to stdout a FORMAT-tarball containing the directory
# $tardir.
#     tardir=directory && $(am__tar) > result.tar
#
# Substitute a variable $(am__untar) that extract such
# a tarball read from stdin.
#     $(am__untar) < result.tar
AC_DEFUN([_AM_PROG_TAR],
[# Always define AMTAR for backward compatibility.  Yes, it's still used
# in the wild :-(  We should find a proper way to deprecate it ...
AC_SUBST([AMTAR], ['$${TAR-tar}'])
m4_if([$1], [v7],
     [am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'],
     [m4_case([$1], [ustar],, [pax],,
              [m4_fatal([Unknown tar format])])
AC_MSG_CHECKING([how to create a $1 tar archive])
# Loop over all known methods to create a tar archive until one works.
_am_tools='gnutar m4_if([$1], [ustar], [plaintar]) pax cpio none'
_am_tools=${am_cv_prog_tar_$1-$_am_tools}
# Do not fold the above two line into one, because Tru64 sh and
# Solaris sh will not grok spaces in the rhs of '-'.
for _am_tool in $_am_tools
do
  case $_am_tool in
  gnutar)
    for _am_tar in tar gnutar gtar;
    do
      AM_RUN_LOG([$_am_tar --version]) && break
    done
    am__tar="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$$tardir"'
    am__tar_="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$tardir"'
    am__untar="$_am_tar -xf -"
    ;;
  plaintar)
    # Must skip GNU tar: if it does not support --format= it doesn't create
    # ustar tarball either.
    (tar --version) >/dev/null 2>&1 && continue
    am__tar='tar chf - "$$tardir"'
    am__tar_='tar chf - "$tardir"'
    am__untar='tar xf -'
    ;;
  pax)
    am__tar='pax -L -x $1 -w "$$tardir"'
    am__tar_='pax -L -x $1 -w "$tardir"'
    am__untar='pax -r'
    ;;
  cpio)
    am__tar='find "$$tardir" -print | cpio -o -H $1 -L'
    am__tar_='find "$tardir" -print | cpio -o -H $1 -L'
    am__untar='cpio -i -H $1 -d'
    ;;
  none)
    am__tar=false
    am__tar_=false
    am__untar=false
    ;;
  esac

  # If the value was cached, stop now.  We just wanted to have am__tar
  # and am__untar set.
  test -n "${am_cv_prog_tar_$1}" && break

  # tar/untar a dummy directory, and stop if the command works
  rm -rf conftest.dir
  mkdir conftest.dir
  echo GrepMe > conftest.dir/file
  AM_RUN_LOG([tardir=conftest.dir && eval $am__tar_ >conftest.tar])
  rm -rf conftest.dir
  if test -s conftest.tar; then
    AM_RUN_LOG([$am__untar <conftest.tar])
    grep GrepMe conftest.dir/file >/dev/null 2>&1 && break
  fi
done
rm -rf conftest.dir

AC_CACHE_VAL([am_cv_prog_tar_$1], [am_cv_prog_tar_$1=$_am_tool])
AC_MSG_RESULT([$am_cv_prog_tar_$1])])
AC_SUBST([am__tar])
AC_SUBST([am__untar])
]) # _AM_PROG_TAR