#!/bin/bash
#  $HeadURL$ $LastChangedRevision$

echo "setting up environment ..."
LOCKFILE=/tmp/x.lock

echo "defining support functions ..."
devariant()
{
    sed -r 's/[1-9][0-9]*/999999/' "$@"
}

shell_lock()
{
    adeshf 'ade_lock "$ERRSTACK_REF" /tmp/x.lock || return $?; sleep 10; return $ADE_OK'
}

perl_lock()
{
    adeperlf '$rc=ADE::lock($errstack_ref, "/tmp/x.lock"); return($rc) if ($rc!=$ADE::OK); sleep(10); return($ADE::OK);'
}

python_lock()
{
    #  '[ x, y, z ][-1]' is the equivalent of C's comma operator: evaluation each item in a list but return the value of the last.
    #  We use it here as a way to turn two statements (sleep and produce-a-value) into a single statement and thereby avoid the
    #  need to indent in a context that doesn't support indentation (i.e. a single line program).
    adepyf 'import time; import ade; rc=ade.lock(errstack, "/tmp/x.lock"); return rc if rc != ade.ok else [ time.sleep(10), ade.ok ][-1]'
}

test_valid_locks()
{
    echo "starting $ADELANG version ..."
    ${ADELANG}_lock &
    echo "giving $ADELANG version a moment to create its lock ..."
    sleep 1
    devariant $LOCKFILE
    
    echo "starting a second $ADELANG version (expect an error) ..."
    ${ADELANG}_lock 2>&1 | devariant
    
    echo "waiting for all $ADELANG version children to exit ..."
    wait
}

test_stale_locks()
{
    echo "starting $ADELANG version ..."
    ${ADELANG}_lock > /dev/null 2>&1 &
    #  Do not use '$!' because that would be the pid of the backgrounded shell
    #  function (i.e. a shell) not of ade{sh,perl,py}f!
    echo "giving $ADELANG version a moment to create its lock ..."
    sleep 5
    PID=$(cat /tmp/x.lock)
    if ! [[ $PID =~ ^[1-9][0-9]+$ ]]; then
        echo "test_stale_locks: lock contents doesn't look like a pid! ($PID)"
    elif ! [ -d /proc/$PID ]; then
        echo "test_stale_locks: lock contents pid ($PID) doesn't appear to be running!"
    else
        echo "test_stale_locks: killing it ..."
        kill -9 $PID
        echo "test_stale_locks: waiting for children to exit ..."
        wait > /dev/null 2>&1
    fi
    echo "starting it again to see if it sees stale lock (expect a warning) ..."
    ${ADELANG}_lock &
    #  This sleep serves a double purpose! It ensures the lock file has been
    #  written by the time we come to read it *and* it ensures that the
    #  stale lock warning and the next echo come out in a consistent order.
    sleep 5
    PID=$(cat /tmp/x.lock)
    if ! [[ $PID =~ ^[1-9][0-9]+$ ]]; then
        echo "test_stale_locks: lock contents doesn't look like a pid! ($PID)"
    elif ! [ -d /proc/$PID ]; then
        echo "test_stale_locks: lock contents pid ($PID) doesn't appear to be running!"
    else
        echo "test_stale_locks: waiting for children to exit ..."
        wait > /dev/null 2>&1
    fi
}

echo "starting test_valid_locks loop (meet valid locks) ..."
for ADELANG in shell perl python; do
    echo "$ADELANG ..."
    test_valid_locks
done

echo "starting test_stale_locks loop (meet state locks) ..."
for ADELANG in shell perl python; do
    echo "$ADELANG ..."
    test_stale_locks
done
echo "all done"