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=head1 NAME |
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|
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Coro::Channel - message queues |
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|
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=head1 SYNOPSIS |
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|
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use Coro::Channel; |
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|
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$q1 = new Coro::Channel <maxsize>; |
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|
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$q1->put ("xxx"); |
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print $q1->get; |
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|
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die unless $q1->size; |
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|
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=head1 DESCRIPTION |
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|
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A Coro::Channel is the equivalent of a pipe: you can put things into it on |
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one end end read things out of it from the other hand. If the capacity of |
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the Channel is maxed out writers will block. Both ends of a Channel can be |
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read/written from as many coroutines as you want. |
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|
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=over 4 |
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|
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=cut |
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|
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package Coro::Channel; |
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|
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no warnings; |
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|
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use Coro (); |
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|
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$VERSION = 4.741; |
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|
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=item $q = new Coro:Channel $maxsize |
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|
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Create a new channel with the given maximum size (unlimited if C<maxsize> |
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is omitted). Giving a size of one gives you a traditional channel, i.e. a |
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queue that can store only a single element (which means there will be no |
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buffering). To buffer one element you have to specify C<2>, and so on. |
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|
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=cut |
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|
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sub new { |
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# [\@contents, [$getwait], $maxsize, [$putwait]]; |
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bless [[], [], $_[1] || (1e30),[]], $_[0]; |
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} |
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|
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=item $q->put ($scalar) |
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|
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Put the given scalar into the queue. |
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|
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=cut |
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|
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sub put { |
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push @{$_[0][0]}, $_[1]; |
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(pop @{$_[0][1]})->ready if @{$_[0][1]}; |
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|
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while (@{$_[0][0]} >= $_[0][2]) { |
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push @{$_[0][3]}, $Coro::current; |
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&Coro::schedule; |
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} |
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} |
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|
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=item $q->get |
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|
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Return the next element from the queue, waiting if necessary. |
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|
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=item $q->timed_get ($timeout) |
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|
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Return the next element from the queue, waiting up to C<$timeout> seconds |
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if necessary. If no element arrives within the given time an empty list |
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will be returned. |
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|
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=cut |
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|
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sub get { |
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while (!@{$_[0][0]}) { |
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push @{$_[0][1]}, $Coro::current; |
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&Coro::schedule; |
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} |
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|
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(pop @{$_[0][3]})->ready if @{$_[0][3]}; |
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shift @{$_[0][0]} |
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} |
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|
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sub timed_get { |
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require Coro::Timer; |
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my $timeout = Coro::Timer::timeout ($_[0]); |
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|
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(pop @{$_[0][3]})->ready if @{$_[0][3]}; |
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|
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while (!@{$_[0][0]}) { |
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push @{$_[0][1]}, $Coro::current; |
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&Coro::schedule; |
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return if $timeout; |
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} |
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|
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shift @{$_[0][0]} |
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} |
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|
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=item $q->size |
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|
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Return the number of elements waiting to be consumed. Please note that: |
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|
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if ($q->size) { |
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my $data = $q->get; |
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} |
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|
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is NOT a race condition but works fine. |
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|
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=cut |
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|
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sub size { |
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scalar @{$_[0][0]} |
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} |
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|
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1; |
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|
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=back |
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|
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=head1 AUTHOR |
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|
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Marc Lehmann <schmorp@schmorp.de> |
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http://home.schmorp.de/ |
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|
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=cut |
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|
