package GRID::Machine;
use strict;
use Data::Dumper;
use List::Util qw(first);
use Scalar::Util qw(blessed reftype);
use Cwd qw{getcwd abs_path};
use IO::File;
use File::Spec;
use File::Path;

$| = 1;

sub send_error {
  my $server = shift;
  my $message = shift;

  $server->remotelog($message);
  $server->send_operation( 
    "DIED",
    GRID::Machine::Result->new( errmsg  => "$server->{host}: $message"),
  );
}

sub send_result {
  my $server = shift;
  my %arg = @_;

  $arg{stdout} =  '' unless defined($arg{stdout});
  $arg{stderr} =  '' unless defined($arg{stderr});
  $arg{errmsg} =  '' unless defined($arg{errmsg});
  $arg{results} =  [] unless defined($arg{results});
  $server->send_operation( "RETURNED", GRID::Machine::Result->new( %arg ));
}

{ # closure for getter-setters

  # List of legal attributes
  my @legal = qw(
    cleanfiles
    cleandirs
    cleanup 
    clientpid
    command
    debug
    Deparse
    err 
    errfile 
    host 
    Indent 
    log 
    logic_id
    logfile 
    perl
    prefix
    pushinc 
    readfunc 
    report
    sendstdout
    startdir 
    startenv
    stored_procedures
    tmpdir
    unshiftinc
    writefunc 
  );
  my %legal = map { $_ => 1 } @legal;

  GRID::Machine::MakeAccessors::make_accessors(@legal);

  my $SERVER;

  sub SERVER {
    return $SERVER;
  }

  sub set_tmpdir {
    my $workdir = File::Spec->tmpdir()."/rperl";
    $workdir .= '1' while (-f $workdir) or (-d $workdir and !(-w $workdir));
    
    return $workdir;
  }

  sub setloganderr { # and set report too
    my ($log, $args, ) = @_;


    my $workdir = $SERVER->{tmpdir};

    my $logname = $args->{$log};
    $logname = "$workdir/$args->{clientpid}_$$.$log" unless $logname;
    if (-d $logname) {
      $logname .= "/rperl$args->{clientpid}_$$.$log";
    }

    my $logfile = IO::File->new("> $logname");
    unless ($logfile) {
        $SERVER->send_error("Can't open $logname for writing. $@");
        return $SERVER
    }
    
    $logfile->autoflush(1);

    $SERVER->{$log} = $logname;
    $SERVER->{$log."file"} = $logfile;

  }

  sub new {
    my $class = shift;
    my %args = @_;

    # Dummy variable $legal. Just to make the perl compiler conscious of the closure ...
    my $legal = \%legal; 
    my $die = 0;
    my $a = first { !exists $legal{$_} } keys(%args);
    die("Error in remote new: Illegal arg  $a. Legal args: @legal\n") if $a;


    # TRUE if remote stdout is sent back to local
    my $sendstdout = $args{sendstdout};

    # TRUE if temporary files will be deleted
    my $cleanup = $args{cleanup};
    $cleanup = 1 unless defined($cleanup);

    my $host = $args{host};
    unless (defined($host)) {
      eval q{
        require Sys::Hostname;
      };
      $host = $@? '$unknown' : Sys::Hostname::hostname();
    }

    my $startdir = $args{startdir};
    if ($startdir) {
      mkdir $startdir unless -x $startdir;
      chdir($startdir) or die "$host: can't change to dir $startdir\n"; 
    }

    # Set initial environment variables
    # No need to check is a HASH ref since it was already checked in the local side
    # (See GRID/Machine.pm)
    my %startenv = %{$args{startenv}};
    for (keys %startenv) {
      $ENV{$_} = $startenv{$_};
    }

    my $pushinc = $args{pushinc} || [];
    for (@$pushinc) {
      push @INC, $_;
    }

    my $unshiftinc = $args{unshiftinc} || [];
    for (@$unshiftinc) {
      unshift @INC, $_;
    }

    my $clientpid = $args{clientpid} || $$;

    my $prefix = $args{prefix} || "$ENV{HOME}/perl5lib";
    unless (-r $prefix) { 
      mkdir $prefix unless -r $prefix; 
      die "$host: can't create directory $prefix\n" unless (-d $prefix) && (-r $prefix);
    }
    push @INC, $prefix;

    # create copy of STDOUT to use as command output (-dk-)
    open(my $CMDIN, "<&STDIN") or die "$host: Can't create copy of STDIN\n";

    my $readfunc = sub {
       if( defined $_[1] ) {
          read( STDIN, $_[0], $_[1] );
       }
       else {
          $_[0] = <STDIN>;
          die "Premature EOF received" unless defined($_[0]);
          length $_[0];
       }
    };

    # create copy of STDOUT to use as command output (-dk-)
    open(my $CMDOUT, ">&STDOUT") or die "$host: Can't create copy of STDOUT\n";
    $CMDOUT->autoflush(1);

    my $writefunc = sub {
       syswrite $CMDOUT, $_[0];
    };

    my $debug = $args{debug} || 0;

    # THIS IS NEW!!!!: Logic ID of the machine
    my $logic_id = $args{logic_id};

    my $handler = {
      sendstdout => $sendstdout,
      readfunc => $readfunc,
      writefunc => $writefunc,
      host  => $host,
      logic_id => $logic_id,
      cleanup  => $cleanup,
      prefix   => $prefix,
      clientpid => $clientpid, 

      # Used to store remote files (see GRID::Machine::RIOHandle)
      FILES     => [],

      # List of absolute names of temporary files
      cleanfiles => [],
      # List of absolute names of temporary directories
      cleandirs => [],

      # Used to store remote subroutines. A remote sub is a GRID::Machine::RemoteSub object
      stored_procedures => {},
      report => $args{report},
      tmpdir => $args{tmpdir},
      debug => $debug,
    };

    $SERVER = bless $handler, $class;

    $SERVER->{tmpdir} = set_tmpdir() unless $SERVER->{tmpdir};
    mkdir $SERVER->{tmpdir} if !(-d $SERVER->{tmpdir});

    setloganderr('log', \%args, );
    # redirect STDOUT - once per remote session! (-dk-)
    open(STDOUT,"> $SERVER->{log}") or do {
        $SERVER->send_error("Can't redirect STDOUT. $@");
        return $SERVER
    };

    setloganderr('err', \%args, );
    setloganderr('report', \%args, );

    return $SERVER;
  }
} # end closure

# Methods in uppercase are PROTOCOL methods
sub QUIT {  
    my $server = shift;

    $server->DESTROY;
    $server->send_operation( "RETURNED");

    # It is not being called upon termination!
    exit( 0 ) 
}

sub read_stdfiles {
  my $server = shift;

  my $sendstdout = $server->{sendstdout};

  my $log = $server->{log};
  my $err = $server->{err};
  my ($rstdout, $rstderr) = ("", "");
  if ($sendstdout) {
    local $/ = undef;
    my $file;
    open($file, $log) or do { 
        $server->remotelog(qq{Can't open stdout file '$log' $@ $!}); 
        return (); 
      };
      $rstdout = <$file>;
    close($file) or $server->remotelog(qq{Closing stdout file '$log' $@ $!});

    open($file, $err) or do { $server->remotelog(qq{Can't open stderr file '$err' $@ $!}); return (); };
      $rstderr = <$file>;
    close($file) or $server->remotelog(qq{Can't close stderr file '$err' $@ $!}); 
  }
  return ($rstdout, $rstderr);
}

sub eval_and_read_stdfiles {
  my $server = shift;
  my $subref = shift;

  my @results = eval { $subref->( @_ ) };

  my $err = "$@$!";
  my @output = $server->read_stdfiles;

    # handling 'GRID::Machine::QUIT' when waiting for 'RESULT' from callback (-dk-)
    if ($err =~ /^EXIT/) { undef $@; exit 0 }

    return GRID::Machine::Result->new(
      errmsg => "Can't recover stdout and stderr",
      results => \@results,
    )
  unless @output;

  my ($rstdout, $rstderr) = @output;

  return GRID::Machine::Result->new(
    stdout => $rstdout, 
    errmsg  => $err, 
    errcode => $?,
    stderr => $rstderr, 
    results => \@results
  );
}

sub EVAL {
  my ($server, $code, $args) = @_;

  my $subref = eval "use strict; sub { $code }";

  if( $@ ) {           # Error while compiling code
     # get rid off of the "#line" header
     $code =~ s{^#package\s\w+;\s+#line\s+\d+\s+"[\\/\w.-]+"\s*}{};
     $server->send_error("Error while compiling eval '".substr($code,0,20)."...'\n$@");
     return;
  }

  if ( defined($args) && (reftype($args) ne 'ARRAY')) {
     $server->send_error( "Error in eval. Args expected. Found instead: $args" );
     return;
  }

  # -dk- look for anonymous callback(s)
  my $results = eval_and_read_stdfiles(
      $server, 
      $subref, 
      map( UNIVERSAL::isa($_, 'GRID::Machine::_RemoteStub') ?  make_callback($server, $_->{id}) : $_, @$args ) 
  );

  if( $@ ) {
     $code =~ m{(.*)};
     $server->send_error( 
       "Error running eval code $1. $@"
     );
     return;
  }

  $server->send_operation( "RETURNED", $results );
  return;
}

sub STORE {
  my ($server, $name, $code) = splice @_,0,3;

  my %args = @_;
  my $politely = $args{politely} || 0; 
  delete($args{politely});

  my $subref = eval qq{ sub { use strict; $code } };
  if( $@ ) {
     $server->send_error("Error while compiling '$name'. $@");
     return;
  }

  if (($politely) && exists($server->{stored_procedures}{$name})) {
    $server->send_result( 
        errmsg  => "Warning! Attempt to overwrite sub '$name'. New version was not installed.",
        results => [ 0 ],
    );
  }
  else {
    # Store a Remote Subroutine Object
    $server->{stored_procedures}{$name} = GRID::Machine::RemoteSub->new(sub => $subref, %args);
    {
      no strict 'refs';
      *{'GRID::Machine::'.$name} = $subref unless GRID::Machine->can($name);
    }
    $server->send_result( 
        results => [ 1 ],
    );
  }
  #$DB::single = 1 if $server->{debug}; # warn!
  return;
}

sub MAKEMETHOD { # makes a remote method of an existing sub 
  my ($server, $name, ) = splice @_,0,2;

  my %args = @_;
  my $politely = $args{politely} || 0; 
  delete($args{politely});

  # TODO: check that exists or that the user is willing to risk
  my $subref = do { no strict 'refs'; \&{$name} };

  if (($politely) && exists($server->{stored_procedures}{$name})) {
    $server->send_result( 
        errmsg  => "Warning! Attempt to overwrite sub '$name'. New version was not installed.",
        results => [ 0 ],
    );
  }
  else {
    # Store a Remote Subroutine Object
    $server->{stored_procedures}{$name} = GRID::Machine::RemoteSub->new(sub => $subref, %args);
    {
      no strict 'refs';
      *{'GRID::Machine::'.$name} = $subref unless GRID::Machine->can($name);
    }
    $server->send_result( 
        results => [ 1 ],
    );
  }
  #$DB::single = 1 if $server->{debug}; # warn!
  return;
}

# -dk-
sub make_callback {
   my ($server, $name) = splice @_,0,2;

   return sub {
      $server->send_operation('CALLBACK', $name, @_);

      while (1) {
         my ($op, @args) = $server->read_operation();

         # what we actually expected - 'RESULT'
         if ($op eq 'RESULT') {
           return wantarray ? @args : $args[0];
         }

         # special case - 'QUIT'
         if ($op eq 'GRID::Machine::QUIT') {
            $server->send_operation("RETURNED");
            # we're inside eval so have to pass 'exit' up
            die "EXIT"
         }

         if ($server->can($op)) {
            $server->$op(@args);
            next
         }

         die "RESULT expected, '$op' received...\n"
      }
   }
}

# -dk-
sub CALLBACK {
   my ($server, $name) = splice @_,0,2;

   # Don't overwrite existing methods
   my $class = ref($server);
   if ($class->can($name)) {
      $server->send_error("Machine $server->{host} already has a method $name");
      return;
   };

   my $callback = make_callback($server, $name);
   {
     no strict 'refs';
     *{$class."::$name"} = $callback;
   }

   $server->send_result( results => [ 0+$callback ] );
}

sub EXISTS {
  my $server = shift;
  my $name = shift;

  $server->send_operation("RETURNED", exists($server->{stored_procedures}{$name}));
}

sub CALL {
  my ($server, $name, $args) = @_;

  my $subref = $server->{stored_procedures}{$name}->{sub};
  if( !defined $subref ) {
     $server->send_error( "Error in RPC. No such stored procedure '$name'" );
     return;
  }

  if ( defined($args) && !UNIVERSAL::isa($args, 'ARRAY')) {
     $server->send_error( "Error in RPC. Args expected. Found instead: $args" );
     return;
  }

  # -dk- look for anonymous callback(s)
  my $results = eval_and_read_stdfiles($server, $subref, 
           map(UNIVERSAL::isa($_, 'GRID::Machine::_RemoteStub') ? make_callback($server, $_->{id}) : $_, @$args ) 
  );

  if( $@ ) {
     $server->send_error("Error running sub $name: $@");
     return;
  }

  my $filter = $server->{stored_procedures}{$name}->filter;
  $results = $results->$filter if $filter;
  $server->send_operation( "RETURNED", $results );
  return;
}

sub MODPUT {
  my $self = shift;
  
  my $pwd = getcwd();

  while (my ($name, $code) = splice @_,0,2) {

    my @a = split "/", $name;

    my $module = pop @a;
    my $dir = File::Spec->catfile($self->prefix, @a);

    if (defined($dir)) {
      # Bug fixed by Alex White. Thanks Alex!
      mkpath($dir) unless -e $dir;
    
      chdir($dir) or $self->send_error("Error chdir $dir $@"), return; 
    }

    open my $f, "> $module" or $self->send_error("Error can't create file $module $@"), return; 
    binmode $f;
    syswrite($f, $code); #or $self->send_error("Error can't save file $module $@"), return;
    close($f) or $self->send_error("Error can't close file $module $@"), return;

    chdir($pwd);

  }
  $self->send_result( 
    #DEBUGGING stdout=> "pwd: ".getcwd()." dir: $dir, module: $module\n", 
    results => [1] 
  );
  return;
}

# Sends a message for inmediate print to the local machine
# Goes in reverse: The remote makes the request the local 
# serves the request
sub gprint {
   SERVER->send_operation('GRID::Machine::GPRINT', @_);
   return 1;
}


# Sends a message for inmediate printf to the local machine
# Goes in reverse: The remote makes the request, the local 
# serves the request
sub gprintf {
   SERVER->send_operation('GRID::Machine::GPRINTF', @_);
   return 1;
}

sub OPEN {
  my ($server, $descriptor) = splice @_,0,2;

  my $file = IO::File->new();

  # Check if is an ouput pipe, i.e. s.t. like:  my $f = $m->open('| sort -n'); 
  # In such case, redirect STDOUT to null
  if ($descriptor =~ m{^\s*\|(.*)}) {
    my $command = $1;
    my $nulldevice = File::Spec->devnull;
    $descriptor = "| ($command) > $nulldevice";
  }
  unless (defined($descriptor) and $file->open($descriptor)) {
     $server->send_error("Error while opening $descriptor. $@");
     return;
  }

  my $files = $server->{FILES};
  push @{$files}, $file; # Watch memory usage

  $server->send_result( 
      results => [ $#$files ],
  );
  return;
}

sub DESTROY {
  my $self = shift;

  close($self->{report});

  unlink $self->{log} if -w  $self->{log};
  unlink $self->{err} if -w  $self->{err};
  unlink $self->{report} if -w  $self->{report} and $self->{cleanup};

  my $cleanfiles = $self->cleanfiles;
  if (reftype($cleanfiles) eq 'ARRAY') {
    while (@{$cleanfiles}) { 
      $_ = shift @{$cleanfiles};
      unlink $_;
    }
  }

  my $cleandirs = $self->cleandirs;
  if (reftype($cleandirs) eq 'ARRAY') {
    while (@{$cleandirs}) { 
      $_ = shift @{$cleandirs};
      rmtree $_;
    }
  }
}

sub remotelog {
  my $server = shift;
  my $msg = join '', @_;
  #my ($package, $filename, $line, $subroutine,) = caller(1);
  #$subroutine = "$filename:$line" if $subroutine =~/__ANON__$/;
  syswrite $server->{reportfile},"$$:".scalar(localtime)." => $msg\n";
}

#########  Remote main() #########
sub main() {
  my $server = shift;

  # Create filter process
  # Check $server is a GRID::Machine
  {
  package main;
  while( 1 ) {
     my ( $operation, @args ) = $server->read_operation( );

     if ($server->can($operation)) {
       $server->$operation(@args);

       # Outermost CALL Should Reset Redirects (-dk-)
       next unless ($operation eq 'GRID::Machine::CALL' || $operation eq 'GRID::Machine::EVAL');
       if ($server->{log}) {
         close STDOUT;
         $server->{log} and open(STDOUT,"> $server->{log}") or do {
           $server->send_error("Can't redirect stdout. $@");
           last
         }
       }
       if ($server->{err}) {
         close STDERR;
         $server->{err} and open(STDERR,"> $server->{err}") or do {
           $server->send_error("Can't redirect stderr. $@");
           last
         }
       }

       next;
     }

     $server->send_error( "Unknown operation $operation\nARGS: @args\n" );
  }
  } # package
}

# GRID::Machine::DEBUG_LOAD_FINISHED 
# signals that the initial bootstraping has finished
sub DEBUG_LOAD_FINISHED {
  my $self = shift;

  no warnings 'once';
  $DB::single = 1 if $self->{debug};
}


# keys are PIDs values are (remote) GRID::Machine::Processes 
my %process;
###################################### Core methods to be build with makemethod ###########
sub fork 
#gm (filter => 'result', 
#gm  around => sub { my $self = shift; my $r = $self->call( 'fork', @_ ); $r->{machine} = $self; $r }
#gm ) 
{
  my $childcode = shift;

  my %args = (stdin => '/dev/null', stdout => '', stderr => '', result => '', args => [], @_);

  my ($stdin, $stdout, $stderr, $result) = @args{'stdin', 'stdout', 'stderr', 'result'};

  $| = 1;

  use File::Temp qw{tempfile};

  unless ($stdout) {
    my $stdoutfile;
    ($stdoutfile, $stdout) = tempfile(SERVER()->{tmpdir}.'/GMFORKXXXXXX', UNLINK => 0, SUFFIX =>'.out');
    close($stdoutfile);
  }

  unless ($stderr) {
    my $stderrfile;
    ($stderrfile, $stderr) = tempfile(SERVER()->{tmpdir}.'/GMFORKXXXXXX', UNLINK => 0, SUFFIX =>'.err');
    close($stderrfile);
  }

  unless ($result) {
    my $resultfile;
    ($resultfile, $result) = tempfile(SERVER()->{tmpdir}.'/GMFORKXXXXXX', UNLINK => 0, SUFFIX =>'.result');
    close($resultfile);
  }

  my $subref = eval <<"EOSUB";
use strict; 
sub { 
    use POSIX qw{setsid};
    setsid(); 
    open(STDIN, "< $stdin");
    open(STDOUT,"> $stdout");
    open(STDERR,"> $stderr");

  $childcode 
};
EOSUB
  if ($@) {
    my $context = substr($childcode,0,100);
    SERVER->send_error("Found errors before forking in code '$context'\n$@\n");
    return;
  }


  my $pid = fork;
  unless (defined($pid)) {
    SERVER->remotelog("Process $$: Can't fork '".substr($childcode,0,10)."'\n$@ $!"); 
    return;
  }

  if ($pid) { # father
    #gprint("Created child $pid\n");
    my $p = bless { 
              pid    => $pid, 
              stdin  => $stdin, 
              stdout => $stdout, 
              stderr => $stderr, 
              result => $result 
            }, 'GRID::Machine::Process';
    $process{$pid} = $p;
    return $p;
  }

  # child

    # admit a single argument of any kind
    my $ar =  $args{args};
    $ar = [ $ar ] unless reftype($ar) and (reftype($ar) eq 'ARRAY');

    my @r = $subref->(@$ar);

    close(STDERR);
    close(STDOUT);

    use Data::Dumper;
    local $Data::Dumper::Indent = 0;
    local $Data::Dumper::Deparse = 1;
    local $Data::Dumper::Purity = 1;
    local $Data::Dumper::Terse = 0;

    open(my $resfile, ">", $result);
    print $resfile Dumper([\@r, \$@]);
    close($resfile);

  exit(0);
}

sub async {
  my $subname = shift;

  # warning potential error. It must be:
  # 'SERVER()->{stored_procedures}{'.$subname.'}{sub}->(@_)', 
  GRID::Machine::fork( "$subname".'(@_)', args => [ @_ ] );
}

sub waitpid #gm (filter => 'result')
{
  my $process = shift;

  $process = $process->result if ($process->isa('GRID::Machine::Result'));

  SERVER->remotelog(Dumper($process));
  #gprint("Synchronizing with $process->{pid} args = <@_>\n");

  my ($status, $deceased);;
  do {
    $deceased = waitpid($process->{pid}, @_ ? @_ : 0);
    $status = $?;

    #gprint("Synchronized: Pid of the deceased process: $deceased\n");
    #gprint("there are processes still running\n") if (!$deceased);

    #SERVER->remotelog("deceased = $deceased");

    #if (kill 0, -$process->{pid}) { gprint("Not answer to 0 signal from process $process->{pid}\n") }
    #else { gprint("Strange: the process $process->{pid} is still alive\n"); }

  } while (kill 0, $process->{pid});

  # if deceased is 0
  # TODO: study flock, may be this way we can synchronize!!

  delete $process{$deceased} if $deceased > 0;

  local $/ = undef;
  open my $fo, $process->{stdout}; # check exists, die, etc.
    my $stdout = <$fo>;
  close($fo);
  CORE::unlink $process->{stdout};

  #gprint("stderr file is: $process->{stderr}\n");
  open my $fe, $process->{stderr}; # or do { SERVER->remotelog("can't open file <$process->{stderr}> $@") }; # check exists, die, etc.
    my $stderr = <$fe>;
  #gprint("stderr is: $stderr\n");
  close($fe);
  CORE::unlink $process->{stderr};

  open my $fr, $process->{result} or do { SERVER->remotelog("can't open file <$process->{stderr}> $@") }; # check exists, die, etc.
    #sleep 1;
    my $result = <$fr>;
    #gprint("result as read from file $process->{result} is  <$result>\n");;
  close($fr);
  CORE::unlink $process->{result};

  $result .= '$VAR1';
  my $val  = eval "no strict; $result";
  #SERVER->remotelog("Errors: '$@'. Result from the asynchronous call: '@$val'");
  
  return bless {
    stdout  => $stdout, 
    stderr  => $stderr, 
    results => $val->[0], 
    status  => $status,    # as in $?
    waitpid => $deceased,  # returned by waitpid
    descriptor => SERVER()->host().':'.$$.':'.$process->{pid},
    machineID  => SERVER()->logic_id,
    errmsg  => ${$val->[1]},  # as $@
  }, 'GRID::Machine::Process::Result';
}

sub waitall #gm (filter => 'result')
{
  my ($status, $deceased);
  do {
    $deceased = CORE::wait();
    $status = $?;

    return $deceased if ($deceased <= 0);
    #gprint("Synchronized: Pid of the deceased process: $deceased\n");
    #gprint("there are processes still running\n") if (!$deceased);

    #SERVER->remotelog("deceased = $deceased");

    #if (kill 0, -$process->{pid}) { gprint("Not answer to 0 signal from process $process->{pid}\n") }
    #else { gprint("Strange: the process $process->{pid} is still alive\n"); }

  } while (kill 0, $deceased);


  # if deceased is 0
  # TODO: study flock, may be this way we can synchronize!!

  my $process = $process{$deceased};
  delete $process{$deceased};

  return $deceased unless $process;

  local $/ = undef;
  open my $fo, $process->{stdout}; # check exists, die, etc.
    my $stdout = <$fo>;
  close($fo);
  CORE::unlink $process->{stdout};

  #gprint("stderr file is: $process->{stderr}\n");
  open my $fe, $process->{stderr}; # or do { SERVER->remotelog("can't open file <$process->{stderr}> $@") }; # check exists, die, etc.
    my $stderr = <$fe>;
  #gprint("stderr is: $stderr\n");
  close($fe);
  CORE::unlink $process->{stderr};

  open my $fr, $process->{result} or do { SERVER->remotelog("can't open file <$process->{stderr}> $@") }; # check exists, die, etc.
    #sleep 1;
    my $result = <$fr>;
    #gprint("result as read from file $process->{result} is  <$result>\n");;
  close($fr);
  CORE::unlink $process->{result};

  $result .= '$VAR1';
  my $val  = eval "no strict; $result";
  #SERVER->remotelog("Errors: '$@'. Result from the asynchronous call: '@$val'");
  
  return bless {
    stdout  => $stdout, 
    stderr  => $stderr, 
    results => $val->[0], 
    status  => $status,    # as in $?
    waitpid => $deceased,  # returned by waitpid
    descriptor => SERVER()->host().':'.$$.':'.$process->{pid},
    machineID  => SERVER()->logic_id,
    errmsg  => ${$val->[1]},  # as $@
  }, 'GRID::Machine::Process::Result';
}

sub kill { #gm (filter => 'result')
  my $signal = shift;

  CORE::kill $signal, @_;
}

sub poll { #gm (filter => 'result')
  CORE::kill 0, @_;
}


1;

package GRID::Machine::RemoteSub;

{
  my @legal = qw( sub filter ); # other attributes: source file, source package, source line, etc
  my %legal = map { $_ => 1 } @legal;

  GRID::Machine::MakeAccessors::make_accessors(@legal);

  sub new {
    my $class = shift;

    bless { @_ }, $class;
  }
}

1;