#!/usr/bin/perl

use strict;
use warnings;
use threads;
use threads::shared;

{
	package Foo;

	use threads::shared;
	use constant INDENT	=> "\t\t\t\t\t\t\t\t";

	sub new {
		my $class = shift;

		my %this;
		$this{_socket} = shift;
		$this{_sendBuffer} = [];

# TBD: Why does this not work?
# 		my %this = {
# 			_socket			=> shift,
# 			_sendBuffer		=> [],
# 		};

		share ($this{_sendBuffer});	# make this a shared variable to allow main thread to lock & manipulate this

		return bless \%this, $class;
	}

	sub serve {
		my $this = shift;

		{	# scope for lock on $Foo->{_sendBuffer}
			print INDENT . "object thread: 1st lock attempt\n";
			lock ($this->{_sendBuffer});
			print INDENT . "object thread: 1st lock acquired...";

			push $this->{_sendBuffer}, "datagram " . scalar (@{$this->{_sendBuffer}});
 			sleep (1);

 			print "    and released!\n";	# pretend to release lock before going out of scope
		}	# release lock

		sleep (1);

		{	# scope for lock on $Foo->{_sendBuffer}
			print INDENT . "object thread: 2nd lock attempt\n";
			lock ($this->{_sendBuffer});
			print INDENT . "object thread: 2nd lock acquired...";

			push $this->{_sendBuffer}, "datagram " . scalar (@{$this->{_sendBuffer}});
 			sleep (1);

			print "    and released!\n";	# pretend to release lock before going out of scope
		}	# release lock
	}
}

my $foo = new Foo();

my $thr1 = threads->create(sub { $foo->serve() });

{	# scope for lock on $foo
	print "main thread: 1st lock attempt\n";
	lock ($foo->{_sendBuffer});
	print "main thread: 1st lock acquired...\n";

	print "    foo send buffer size: " . scalar (@{$foo->{_sendBuffer}}) . "\n";
	sleep (1);

	print "main thread: 1st lock released!\n";
}	# release lock

sleep (1);

{	# scope for lock on $foo
	print "main thread: 2nd lock attempt\n";
	lock ($foo->{_sendBuffer});
	print "main thread: 2nd lock acquired...\n";

	print "    foo send buffer size: " . scalar (@{$foo->{_sendBuffer}}) . "\n";
	sleep (1);

	print "main thread: 2nd lock released!\n";
}	# release lock

$thr1->join();		# for some reason, this calls the destructor of foo (if present): so the thread obtained a copy of foo to work with?

print "main thread: object thread joined\n\n";

my $index = 0;
foreach my $item (@{$foo->{_sendBuffer}}) {	# loop through contents of sendBuffer
      print "foo->{_sendBuffer[$index]}: $item\n";	# output sendBuffer contents
      $index++;
}

undef ($foo);	# destroy object