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lib/Mutex/Channel.pm  view on Meta::CPAN

###############################################################################
## ----------------------------------------------------------------------------
## Mutex::Channel - Mutex locking via a pipe or socket.
##
###############################################################################

package Mutex::Channel;

use strict;
use warnings;

no warnings qw( threads recursion uninitialized once );

our $VERSION = '1.011';

use if $^O eq 'MSWin32', 'threads';
use if $^O eq 'MSWin32', 'threads::shared';

use base 'Mutex';
use Mutex::Util;
use Scalar::Util 'looks_like_number';
use Time::HiRes 'alarm';

my $is_MSWin32 = ($^O eq 'MSWin32') ? 1 : 0;
my $use_pipe = ($^O !~ /mswin|mingw|msys|cygwin/i && $] gt '5.010000');
my $tid = $INC{'threads.pm'} ? threads->tid : 0;

sub CLONE {
    $tid = threads->tid if $INC{'threads.pm'};
}

sub Mutex::Channel::_guard::DESTROY {
    my ($pid, $obj) = @{ $_[0] };
    CORE::syswrite($obj->{_w_sock}, '0'), $obj->{ $pid } = 0 if $obj->{ $pid };

    return;
}

sub DESTROY {
    my ($pid, $obj) = ($tid ? $$ .'.'. $tid : $$, @_);
    CORE::syswrite($obj->{_w_sock}, '0'), $obj->{ $pid } = 0 if $obj->{ $pid };

    if ( $obj->{_init_pid} eq $pid ) {
        $use_pipe
            ? Mutex::Util::destroy_pipes($obj, qw(_w_sock _r_sock))
            : Mutex::Util::destroy_socks($obj, qw(_w_sock _r_sock));
    }

    return;
}

###############################################################################
## ----------------------------------------------------------------------------
## Public methods.
##
###############################################################################

sub new {
    my ($class, %obj) = (@_, impl => 'Channel');
    $obj{_init_pid} = $tid ? $$ .'.'. $tid : $$;
    $obj{_t_lock} = threads::shared::share( my $t_lock ) if $is_MSWin32;

    $use_pipe
        ? Mutex::Util::pipe_pair(\%obj, qw(_r_sock _w_sock))
        : Mutex::Util::sock_pair(\%obj, qw(_r_sock _w_sock));

    CORE::syswrite($obj{_w_sock}, '0');

    return bless(\%obj, $class);
}

sub lock {
    my ($pid, $obj) = ($tid ? $$ .'.'. $tid : $$, shift);

    unless ($obj->{ $pid }) {
        CORE::lock($obj->{_t_lock}), Mutex::Util::_sock_ready($obj->{_r_sock})
            if $is_MSWin32;
        Mutex::Util::_sysread($obj->{_r_sock}, my($b), 1), $obj->{ $pid } = 1;
    }

    return;
}

sub guard_lock {
    &lock(@_);