Coro/Coro/Signal.pm

=head1 NAME

Coro::Signal - coroutine signals (binary semaphores)

=head1 SYNOPSIS

 use Coro::Signal;

 $sig = new Coro::Signal;

 $sig->wait; # wait for signal

 # ... some other "thread"

 $sig->send;

=head1 DESCRIPTION

This module implements signal/binary semaphores/condition variables
(basically all the same thing). You can wait for a signal to occur or send
it, in which case it will wake up one waiter, or it can be broadcast,
waking up all waiters.

=over 4

=cut

package Coro::Signal;

no warnings qw(uninitialized);

use Coro ();

$VERSION = 0.5;

=item $s = new Coro::Signal;

Create a new signal.

=cut

sub new {
   # [flag, [pid's]]
   bless [], $_[0];
}

=item $s->wait

Wait for the signal to occur. Returns immediately if the signal has been
sent before.

=cut

sub wait {
   if ($_[0][0]) {
      $_[0][0] = 0;
   } else {
      push @{$_[0][1]}, $Coro::current;
      Coro::schedule;
   }
}

=item $s->send

Send the signal, waking up I<one> waiting process or remember the signal
if no process is waiting.

=cut

sub send {
   if (@{$_[0][1]}) {
      (shift @{$_[0][1]})->ready;
   } else {
      $_[0][0] = 1;
   }
}

=item $s->broadcast

Send the signal, waking up I<all> waiting process. If no process is
waiting the signal is lost.

=cut

sub broadcast {
   (shift @{$_[0][1]})->ready while @{$_[0][1]};
}

=item $s->awaited

Return true when the signal is beign awaited by some process.

=cut

sub awaited {
   !!@{$_[0][1]};
}

1;

=back

=head1 AUTHOR

 Marc Lehmann <pcg@goof.com>
 http://www.goof.com/pcg/marc/

=cut

Revision:	1.17
Committed:	Mon Sep 24 01:36:20 2001 UTC (22 years, 8 months ago) by root
Branch:	MAIN
Changes since 1.16:	+1 -1 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3	root	1.2	Coro::Signal - coroutine signals (binary semaphores)
4	root	1.1
5			=head1 SYNOPSIS
6
7			use Coro::Signal;
8
9			$sig = new Coro::Signal;
10
11			$sig->wait; # wait for signal
12
13			# ... some other "thread"
14
15			$sig->send;
16
17			=head1 DESCRIPTION
18
19	root	1.11	This module implements signal/binary semaphores/condition variables
20			(basically all the same thing). You can wait for a signal to occur or send
21			it, in which case it will wake up one waiter, or it can be broadcast,
22			waking up all waiters.
23
24	root	1.1	=over 4
25
26			=cut
27
28			package Coro::Signal;
29
30	root	1.17	no warnings qw(uninitialized);
31	root	1.16
32	root	1.5	use Coro ();
33	root	1.1
34	root	1.15	$VERSION = 0.5;
35	root	1.1
36	root	1.3	=item $s = new Coro::Signal;
37
38			Create a new signal.
39
40			=cut
41
42	root	1.1	sub new {
43	root	1.3	# [flag, [pid's]]
44	root	1.1	bless [], $_[0];
45			}
46
47	root	1.3	=item $s->wait
48
49	root	1.8	Wait for the signal to occur. Returns immediately if the signal has been
50			sent before.
51	root	1.3
52			=cut
53
54	root	1.1	sub wait {
55	root	1.3	if ($_[0][0]) {
56			$_[0][0] = 0;
57	root	1.1	} else {
58	root	1.5	push @{$_[0][1]}, $Coro::current;
59			Coro::schedule;
60	root	1.1	}
61			}
62
63	root	1.3	=item $s->send
64
65	root	1.8	Send the signal, waking up I<one> waiting process or remember the signal
66			if no process is waiting.
67	root	1.3
68			=cut
69
70	root	1.1	sub send {
71	root	1.3	if (@{$_[0][1]}) {
72			(shift @{$_[0][1]})->ready;
73	root	1.1	} else {
74	root	1.3	$_[0][0] = 1;
75	root	1.1	}
76			}
77
78	root	1.3	=item $s->broadcast
79
80	root	1.8	Send the signal, waking up I<all> waiting process. If no process is
81			waiting the signal is lost.
82	root	1.3
83			=cut
84
85			sub broadcast {
86			(shift @{$_[0][1]})->ready while @{$_[0][1]};
87			}
88
89			=item $s->awaited
90
91			Return true when the signal is beign awaited by some process.
92
93			=cut
94
95	root	1.1	sub awaited {
96	root	1.3	!!@{$_[0][1]};
97	root	1.1	}
98
99			1;
100
101			=back
102
103			=head1 AUTHOR
104
105			Marc Lehmann <pcg@goof.com>
106			http://www.goof.com/pcg/marc/
107
108			=cut
109