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# should be call by FvwmScript-ComExample as:
# perl [-w] fvwm-script-ComExample --com-name ComExample-pid
# where pid is the process id of FvwmScript-ComExample
use strict;
use Getopt::Long;
my $comName = "";
my $userHome = $ENV{'HOME'} || "./.";
my $userDir = $ENV{'FVWM_USERDIR'} || "$userHome/.fvwm";
my $scriptName = ($0 =~ m:([^/]+)$:, $1);
GetOptions(
"help|h" => \&showHelp,
"com-name=s" => \$comName,
) || showHelp();
showHelp() if ($comName eq "");
# the fifos for the communication with FvwmScript
my $outFifo = ".tmp-com-out-" . $comName;
my $inFifo = ".tmp-com-in-" . $comName;
# extract the the pid of FvwmScript-ComExample
my $comPid = $comName;
$comPid =~ s/ComExample-//;
showHelp() if ($comPid !~ /^\d+$/);
# startup stuff:
# nothing :o)
# go to the communication loop (never return)
comLoop();
#-------------------------------------------------------------------------------
# usage
sub showHelp {
print "\n";
print "$scriptName must be run by FvwmScript-ComExample as follow:\n\n";
print "\tperl $scriptName --com-name ComExample-pid\n\n";
print "where pid is the process id of FvwmScript-ComExample\n";
print "\n";
exit 0;
}
#-------------------------------------------------------------------------------
# the communication loop
sub comLoop {
my $command = "";
my $return = "";
my $count=0;
chdir($userDir) || die "No FvwmConfigHome $userDir";
# paranoia
unlink($outFifo) if -p "$outFifo";
unlink($inFifo) if -p "$inFifo";
while(1) {
# read the command and check every 10 sec if FvwmScript-ComExemple
# is still alive
myMakeFifo($inFifo) if ! -p "$inFifo";
eval {
local $SIG{ALRM} = \&checkScript;
alarm(10);
# block unless FvwmScript write on $inFifo
open(IN,"$inFifo") || die "cannot open $inFifo";
alarm(0);
# read the message
($command)=(<IN>);
chomp($command);
close(IN);
};
if ($@ =~ /^cannot/) {
print STDERR "$comName: cannot read in fifo $inFifo\n";
unlink("$inFifo") if -p "$inFifo";
exit(1);
}
if ($@ =~ /^NoScript/) {
print STDERR "$comName: No more FvwmScript-ComExample: exit!\n";
unlink("$inFifo") if -p "$inFifo";
exit(0);
}
if ($@ =~ /^Script/) {
next;
}
unlink($inFifo);
# build the answer
$return = "";
if ($command eq "startup")
{
$return = "fvwm-script-ComExample.pl perl script is up";
}
elsif ($command eq "count")
{
$count++;
$return = "Get $count count messages";
}
elsif ($command eq "multilines")
{
# return an answer ready for the FvwmScript Parse function
my @r = ();
$r[0] = "line1 (" . int(rand 20) . ")";
$r[1] = "Second Line (" . int(rand 20) . ")";
$r[2] = "An other Line (" . int(rand 20) . ")";
$return = buildAnswerForParse(@r);
}
# ...etc.
# --------------------------
elsif ($command eq "exit") {
exit(0);
}
else {
print STDERR "$comName: unknown command $command\n";
$return = "0";
}
# send the answer to FvwmScript, we wait 10 sec
myMakeFifo($outFifo);
eval {
local $SIG{ALRM} = sub { die "Timeout" };
alarm(10);
# this line block until FvwmScript take the answer
open(OUT,">$outFifo") || die "$comName: cannot write on fifo $outFifo";
alarm(0);
print OUT $return;
close(OUT);
};
if ($@ =~ /cannot/) {
print STDERR "$comName: cannot write on fifo $outFifo\n";
unlink($outFifo);
exit(1);
}
if ($@ =~ /Timeout/) {
print STDERR "$comName: FvwmScript do not read my answer!\n";
}
unlink($outFifo);
} # while
}
#-----------------------------------------------------------------------------
# multi-lines to one line for the Parse FvwmScript function
sub buildAnswerForParse {
my @r = @_;
my $out = "";
my $l = 0;
foreach (@r) {
$l = length($_);
$out .= "0" x (4 - length($l)) . "$l" . $_;
}
return $out;
}
#-----------------------------------------------------------------------------
# make a fifo
sub myMakeFifo {
my ($fifo) = @_;
system("mkfifo '$fifo'");
}
#----------------------------------------------------------------------------
# An alarm handler to check if FvwmScript-ComExample is still alive
sub checkScript {
die "Script" unless ($comPid);
my $test = 0;
$test = 1 if kill 0 => $comPid;
if ($test) { die "Script"; }
else {
unlink($outFifo) if -p "$outFifo";
unlink($inFifo) if -p "$inFifo";
die "NoScript";
}
}
#-----------------------------------------------------------------------------
# For killing the FvwmScript-ComExample if an error happen in this script
END {
if ($?) {
my $message = "$scriptName: internal error $?\n";
$message .= "\tOS error: $!\n" if $!;
# actually the following is never executed on unix
$message .= "\tOS error 2: $^E\n" if $^E && !($! && $^E eq $!);
unlink($outFifo) if -p "$outFifo";
unlink($inFifo) if -p "$inFifo";
if ($comPid) {
kill(9, $comPid);
$message .= "\tkilling FvwmScript-ComExample";
}
print STDERR "$message\n";
}
}
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