#!/bin/sh
# Ensure all logs are output upon file truncation

# Copyright (C) 2015-2020 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/>.

. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
print_ver_ tail

check_tail_output()
{
  local delay="$1"
  grep "$tail_re" out > /dev/null ||
    { sleep $delay; return 1; }
}

# Terminate any background tail process
cleanup_() { kill $pid 2>/dev/null && wait $pid; }

# Speedup the non inotify case
fastpoll='-s.1 --max-unchanged-stats=1'

for follow in '-f' '-F'; do
  for mode in '' '---disable-inotify'; do
    rm -f out
    seq 10 > f || framework_failure_

    tail $follow $mode $fastpoll f > out 2>&1 & pid=$!

    # Wait up to 12.7s for tail to start
    tail_re='^10$' retry_delay_ check_tail_output .1 7 ||
      { cat out; fail=1; }

    seq 11 15 > f || framework_failure_

    # Wait up to 12.7s for new data
    tail_re='^15$' retry_delay_ check_tail_output .1 7 ||
      { cat out; fail=1; }

    cleanup_
  done
done

Exit $fail