advcoproc

#!/bin/bashfill

[[ ! -e /dev/fd/69 ]] && exec ${CALLBACKFD:=69}<> <(:); # callback fd

exec 9>&2 2> /dev/null;
${COMMAND:=$1} 0< "${INPUT:=$2}" 1> "${OUTPUT:=$3}" 2> "${ERROR:=${4:-/dev/fd/9}}" &
exec 2>&9 9>&-;

declare -gA $ALIAS[pid]=\$! $ALIAS[command]="$COMMAND" $ALIAS[0]="$INPUT" \
$ALIAS[1]="$OUTPUT" $ALIAS[2]="$ERROR";

disown \${$ALIAS[pid]};

function ${ALIAS}.write() {
    (( \$# > 0 )) && {
        echo "\$@" > "$INPUT"
    } || {
        cat > "$INPUT";
    }
}

function ${ALIAS}.read() {
    read "\$@" < "$OUTPUT";
}

function ${ALIAS}.pid() {
    echo -n \${$ALIAS[pid]};
}

function ${ALIAS}.signal() { kill "\$@" \${$ALIAS[pid]}; }
function ${ALIAS}.pause() { kill -s SIGSTOP \${$ALIAS[pid]}; }
function ${ALIAS}.continue() { kill -s SIGCONT \${$ALIAS[pid]}; }

function ${ALIAS}.die() {
    kill -s SIGKILL \${$ALIAS[pid]};
    unset -f $(echo -n ${ALIAS}.{signal,pause,continue,pid,read,write,die});
    unset $ALIAS; trap - SIGRTMIN;
}

trap "{
    read -u 69 __CALLBACK; eval \$__CALLBACK; unset __CALLBACK;
}" SIGRTMIN;