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package Thread::Queue; |
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|
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use threads::shared; |
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use strict; |
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|
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our $VERSION = '2.00'; |
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|
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=head1 NAME |
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|
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Thread::Queue - thread-safe queues |
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|
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=head1 SYNOPSIS |
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|
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use Thread::Queue; |
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my $q = new Thread::Queue; |
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$q->enqueue("foo", "bar"); |
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my $foo = $q->dequeue; # The "bar" is still in the queue. |
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my $foo = $q->dequeue_nb; # returns "bar", or undef if the queue was empty |
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my $left = $q->pending; # returns the number of items still in the queue |
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|
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=head1 DESCRIPTION |
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|
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A queue, as implemented by C<Thread::Queue> is a thread-safe |
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data structure much like a list. Any number of threads can safely |
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add elements to the end of the list, or remove elements from the head |
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of the list. (Queues don't permit adding or removing elements from |
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the middle of the list). |
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|
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=head1 FUNCTIONS AND METHODS |
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|
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=over 8 |
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|
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=item new |
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|
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The C<new> function creates a new empty queue. |
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|
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=item enqueue LIST |
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|
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The C<enqueue> method adds a list of scalars on to the end of the queue. |
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The queue will grow as needed to accommodate the list. |
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|
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=item dequeue |
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|
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The C<dequeue> method removes a scalar from the head of the queue and |
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returns it. If the queue is currently empty, C<dequeue> will block the |
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thread until another thread C<enqueue>s a scalar. |
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|
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=item dequeue_nb |
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|
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The C<dequeue_nb> method, like the C<dequeue> method, removes a scalar from |
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the head of the queue and returns it. Unlike C<dequeue>, though, |
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C<dequeue_nb> won't block if the queue is empty, instead returning |
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C<undef>. |
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|
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=item pending |
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|
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The C<pending> method returns the number of items still in the queue. |
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|
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=back |
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|
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=head1 SEE ALSO |
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|
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L<threads>, L<threads::shared> |
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|
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=cut |
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|
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sub new { |
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my $class = shift; |
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my @q : shared = @_; |
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return bless \@q, $class; |
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} |
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|
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sub dequeue { |
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my $q = shift; |
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lock(@$q); |
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cond_wait @$q until @$q; |
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cond_signal @$q if @$q > 1; |
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return shift @$q; |
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} |
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|
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sub dequeue_nb { |
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my $q = shift; |
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lock(@$q); |
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return shift @$q; |
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} |
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|
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sub enqueue { |
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my $q = shift; |
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lock(@$q); |
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push @$q, @_ and cond_signal @$q; |
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} |
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|
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sub pending { |
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my $q = shift; |
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lock(@$q); |
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return scalar(@$q); |
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} |
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1; |
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