#!@PERLV_PATH@
##
##
## Copyright (C) 1997 by Henry Kilmer and Peter Whiting.
## All rights reserved.
##
## This software may be freely copied, modified and redistributed without
## fee for non-commerical purposes provided that this copyright notice is
## preserved intact on all copies and modified copies.
## 
## There is no warranty or other guarantee of fitness of this software.
## It is provided solely "as is". The author(s) disclaim(s) all
## responsibility and liability with respect to this software's usage
## or its effect upon hardware, computer systems, other software, or
## anything else.
##
##
#
# PAR - parallel processing of command
#
# par -q -n # -l logfile -c command -x -d
#   -q = quiet mode (don't log anything to the logfiles)
#   -n # = number of processes to run at once (default = 3)
#   -l logfile = logfile to store par logging into (.0-.n)
#   -c command = command to run (can also be in the list
#                of routers begining with a :
#   -x = view par logs as they run through xterms
#   -i = run commands through interactive xterms
#   -d = print debugging to stderr
#
# par takes a list of items to run a command on.  If the list entry begins
# with a ":" the remainder of the line is the command to run ("{}" will be
# replaced with each subsequent item in the list.  If the list entry begins
# with a "#", the entry is ignored.  If a command is defined (either with
# the -c or with a : line) any entry thereafter will be applied to the
# command by replacing the {} brackets.  In no cammand is defined, then each
# line is assumed to be a command to be run.
#
use Getopt::Std;
getopts('n:l:c:xidq');
$procs=$opt_n;  $procs=3 if(!$procs);
$command=$opt_c;$command="{}" if(!$command);
$parlog=$opt_l; $parlog="par.log.".time if(!$parlog);
$debug=$opt_d;

if ($opt_q && ($opt_x || $opt_l)) {
    print STDERR "-q nullifies -x and -l\n";
    exit 1;
}

$signalled=0;

sub handler { 
    $signalled++;
    print STDERR "Received signal - ending run ($signalled).\n";
    if($signalled>1) {
	printf STDERR "Ok - killing $id!\n";
	kill 9, 0;
        exit(1);
    }
}

$SIG{'INT'} = 'handler';
$SIG{'TERM'} = 'handler';
$SIG{'QUIT'} = 'handler';

sub start {
    local($cmd,$logfile)=@_;
    unless ($id=fork) {
	if (!$opt_q) {
	    local($date)=scalar localtime;
	    open(LOG,">>$logfile");
	    print(LOG "!!!!!!!\n!$date: $cmd\n!!!!!!!\n");
	    close(LOG);
	    exec "($cmd) >>$logfile";
	} else {
	    exec "($cmd)";
	}
        exit 0;
    }
    print STDERR "Starting $cmd: process id=$id logfile=$logfile\n" if ($debug);
    $id;
}

sub finish {
    if(($id=wait)>0){
        $logfile=$log{$id};
        print STDERR "$id finished (logfile $logfile)\n" if($logfile && $debug);
        $logfile;
    }
}

sub watchf {
    local($log)=@_;
    unless(fork) { exec "xterm -e tail -f $log" ; exit 1; }
}

for($i=0;<>;$i++) {
    chop;
    if (/^\#/){$i--;next;}
    if(/^:(.*)$/){$command=$1;$i--;next;}
    if ($i<$procs) {
	$logfile="running.$i"; $logfile="$parlog.$i" if (!$opt_q);
	watchf($logfile) if($opt_x);
    } else { $logfile=finish; }
    last if $signalled;
    if ($logfile) {
        $cmd = $command;
        $cmd =~ s/\{\}/$_/g;
	$cmd = "xterm -e $cmd" if ($opt_i);
        $id=start($cmd,$logfile);
        $log{$id}=$logfile;
    }
    print STDERR "$i/$procs: $_: id=$id, log=$log{$id}\n" if ($debug);
}

if($signalled && !eof) {
    $i--;
    print STDERR "Signalled - not running these:\n$_\n";
    while(<>){print STDERR;}
} else {
    print STDERR "All work assigned.  Waiting for remaining processes.\n" if ($debug);
}
$procs=$i if ($i<$procs);
while($procs) {
    $procs-- if(finish);
}
print STDERR "Complete\n" if ($debug);