Coro/Coro/Channel.pm

=head1 NAME

Coro::Channel - message queues

=head1 SYNOPSIS

 use Coro::Channel;

 $q1 = new Coro::Channel <maxsize>;

 $q1->put("xxx");
 print $q1->get;

 die unless $q1->size;

=head1 DESCRIPTION

A Coro::Channel is the equivalent of a pipe: you can put things into it on
one end end read things out of it from the other hand. If the capacity of
the Channel is maxed out writers will block. Both ends of a Channel can be
read/written from as many coroutines as you want.

=over 4

=cut

package Coro::Channel;

use Coro ();

$VERSION = 0.10;

=item $q = new Coro:Channel $maxsize

Create a new channel with the given maximum size (unlimited if C<maxsize>
is omitted). Giving a size of one gives you a traditional channel, i.e. a
queue that can store only a single element.

=cut

sub new {
   # [\@contents, [$getwait], $maxsize, [$putwait]];
   bless [[], [], $_[1] || (1e30),[]], $_[0];
}

=item $q->put($scalar)

Put the given scalar into the queue.

=cut

sub put {
   push @{$_[0][0]}, $_[1];

   (pop @{$_[0][1]})->ready if @{$_[0][1]};

   while (@{$_[0][0]} >= $_[0][2]) {
      push @{$_[0][3]}, $Coro::current;
      &Coro::schedule;
   }
}

=item $q->get

Return the next element from the queue, waiting if necessary.

=cut

sub get {
   (pop @{$_[0][3]})->ready if @{$_[0][3]};

   while (!@{$_[0][0]}) {
      push @{$_[0][1]}, $Coro::current;
      &Coro::schedule;
   }

   shift @{$_[0][0]};
}

=item $q->size

Return the number of elements waiting to be consumed. Please note that:

  if ($q->size) {
     my $data = $q->get;
  }

is NOT a race condition but works fine.

=cut

sub size {
   scalar @{$_[0][0]};
}

1;

=back

=head1 AUTHOR

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

=cut

Revision:	1.8
Committed:	Sat Jul 21 18:21:45 2001 UTC (22 years, 10 months ago) by root
Branch:	MAIN
Changes since 1.7:	+14 -8 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			Coro::Channel - message queues
4
5			=head1 SYNOPSIS
6
7			use Coro::Channel;
8
9			$q1 = new Coro::Channel <maxsize>;
10
11			$q1->put("xxx");
12			print $q1->get;
13
14			die unless $q1->size;
15
16			=head1 DESCRIPTION
17
18	root	1.8	A Coro::Channel is the equivalent of a pipe: you can put things into it on
19			one end end read things out of it from the other hand. If the capacity of
20			the Channel is maxed out writers will block. Both ends of a Channel can be
21			read/written from as many coroutines as you want.
22
23	root	1.1	=over 4
24
25			=cut
26
27			package Coro::Channel;
28
29	root	1.3	use Coro ();
30	root	1.1
31	root	1.8	$VERSION = 0.10;
32	root	1.1
33			=item $q = new Coro:Channel $maxsize
34
35			Create a new channel with the given maximum size (unlimited if C<maxsize>
36	root	1.8	is omitted). Giving a size of one gives you a traditional channel, i.e. a
37			queue that can store only a single element.
38	root	1.1
39			=cut
40
41			sub new {
42	root	1.7	# [\@contents, [$getwait], $maxsize, [$putwait]];
43	root	1.8	bless [[], [], $_[1] \|\| (1e30),[]], $_[0];
44	root	1.1	}
45
46			=item $q->put($scalar)
47
48			Put the given scalar into the queue.
49
50			=cut
51
52			sub put {
53			push @{$_[0][0]}, $_[1];
54	root	1.7
55	root	1.1	(pop @{$_[0][1]})->ready if @{$_[0][1]};
56	root	1.7
57	root	1.8	while (@{$_[0][0]} >= $_[0][2]) {
58			push @{$_[0][3]}, $Coro::current;
59			&Coro::schedule;
60	root	1.7	}
61	root	1.1	}
62
63			=item $q->get
64
65			Return the next element from the queue, waiting if necessary.
66
67			=cut
68
69			sub get {
70	root	1.8	(pop @{$_[0][3]})->ready if @{$_[0][3]};
71
72	root	1.1	while (!@{$_[0][0]}) {
73	root	1.3	push @{$_[0][1]}, $Coro::current;
74			&Coro::schedule;
75	root	1.1	}
76	root	1.7
77	root	1.1	shift @{$_[0][0]};
78			}
79
80			=item $q->size
81
82			Return the number of elements waiting to be consumed. Please note that:
83
84			if ($q->size) {
85			my $data = $q->get;
86			}
87
88			is NOT a race condition but works fine.
89
90			=cut
91
92			sub size {
93			scalar @{$_[0][0]};
94			}
95
96			1;
97
98			=back
99
100			=head1 AUTHOR
101
102			Marc Lehmann <pcg@goof.com>
103			http://www.goof.com/pcg/marc/
104
105			=cut
106