package IPC::SRLock::Sysv;
use namespace::autoclean;
use English qw( -no_match_vars );
use File::DataClass::Types qw( Object OctalNum PositiveInt );
use IPC::ShareLite qw( :lock );
use IPC::SRLock::Utils qw( Unspecified hash_from loop_until throw );
use Storable qw( nfreeze thaw );
use Try::Tiny;
use Moo;
extends q(IPC::SRLock::Base);
# Attribute constructors
my $_build__share = sub {
my $self = shift; my $share;
try { $share = IPC::ShareLite->new( '-key' => $self->lockfile,
'-create' => 1,
'-mode' => $self->mode,
'-size' => $self->size ) }
catch {
# uncoverable subroutine
throw "${_}: ${OS_ERROR}"; # uncoverable statement
};
return $share;
};
# Public attributes
has 'lockfile' => is => 'ro', isa => PositiveInt, default => 12_244_237;
has 'mode' => is => 'ro', isa => OctalNum, coerce => 1, default => '0666';
has 'size' => is => 'ro', isa => PositiveInt, default => 65_536;
# Private attributes
has '_share' => is => 'lazy', isa => Object, builder => $_build__share;
# Construction
sub BUILD {
my $self = shift; $self->_share; return;
}
# Private methods
my $_expire_lock = sub {
my ($self, $data, $key, $lock) = @_;
$self->log->error
( $self->_timeout_error
( $key, $lock->{spid}, $lock->{stime}, $lock->{timeout} ) );
delete $data->{ $key };
return 0;
};
my $_unlock_share = sub {
my $self = shift; defined $self->_share->unlock and return 1;
throw 'Failed to unset semaphore'; # uncoverable statement
};
my $_write_shared_mem = sub {
my ($self, $data) = @_;
try { $self->_share->store( nfreeze $data ) }
catch {
throw "${_}: ${OS_ERROR}"; # uncoverable statement
};
return $self->$_unlock_share;
};
my $_read_shared_mem = sub {
my ($self, $for_update, $async) = @_; my $data;
my $mode = $for_update ? LOCK_EX : LOCK_SH; $async and $mode |= LOCK_NB;
my $lock = $self->_share->lock( $mode );
defined $lock or throw 'Failed to set semaphore';
$lock or return; # Async operation would have blocked
try { $data = $self->_share->fetch; $data = $data ? thaw( $data ) : {} }
catch {
throw "${_}: ${OS_ERROR}"; # uncoverable statement
};
not $for_update and $self->$_unlock_share;
return $data;
};
my $_reset = sub {
my ($self, $args) = @_; my $key = $args->{k}; my $pid = $args->{p};
my $shm_content = $self->$_read_shared_mem( 1 );
my $lock; exists $shm_content->{ $key }
and $lock = $shm_content->{ $key }
and $lock->{spid} != $pid
and $self->$_unlock_share
and throw 'Lock [_1] set by another process', [ $key ];
not delete $shm_content->{ $key } and $self->$_unlock_share
and throw 'Lock [_1] not set', [ $key ];
return $self->$_write_shared_mem( $shm_content );
};
my $_set = sub {
my ($self, $args, $now) = @_; my $key = $args->{k}; my $pid = $args->{p};
my $shm_content = $self->$_read_shared_mem( 1, $args->{async} ) or return 0;
my $lock; exists $shm_content->{ $key }
and $lock = $shm_content->{ $key }
and $lock->{timeout}
and $now > $lock->{stime} + $lock->{timeout}
and $lock = $self->$_expire_lock( $shm_content, $key, $lock );
$lock and $self->$_unlock_share and return 0;
$shm_content->{ $key }
= { spid => $pid, stime => $now, timeout => $args->{t} };
$self->$_write_shared_mem( $shm_content );
$self->log->debug( "Lock ${key} set by ${pid}" );
return 1;
};
# Public methods
sub list {
my $self = shift; my $data = $self->$_read_shared_mem; my $list = [];
while (my ($key, $info) = each %{ $data }) {
push @{ $list }, { key => $key,
pid => $info->{spid },
stime => $info->{stime },
timeout => $info->{timeout} };
}
return $list;
}
sub reset {
my $self = shift; return $self->$_reset( $self->_get_args( @_ ) );
}
sub set {
my ($self, @args) = @_; return loop_until( $_set )->( $self, @args );
}
1;
__END__
=pod
=encoding utf-8
=head1 Name
IPC::SRLock::Sysv - Set / reset locks using System V IPC
=head1 Synopsis
use IPC::SRLock;
my $config = { type => q(sysv) };
my $lock_obj = IPC::SRLock->new( $config );
=head1 Description
Uses System V semaphores to lock access to a shared memory file
=head1 Configuration and Environment
This class defines accessors for these attributes:
=over 3
=item C<lockfile>
The key the the semaphore. Defaults to 12_244_237
=item C<mode>
Mode to create the shared memory file. Defaults to 0666
=item C<size>
Maximum size of a shared memory segment. Defaults to 65_536
=back
=head1 Subroutines/Methods
=head2 BUILD
Create the shared memory segment at construction time
=head2 list
List the contents of the lock table
=head2 reset
Delete a lock from the lock table
=head2 set
Set a lock in the lock table
=head1 Diagnostics
None
=head1 Dependencies
=over 3
=item L<File::DataClass>
=item L<IPC::ShareLite>
=item L<IPC::SRLock::Base>
=item L<Moo>
=item L<Storable>
=item L<Time::HiRes>
=item L<Try::Tiny>
=back
=head1 Incompatibilities
There are no known incompatibilities in this module
=head1 Bugs and Limitations
There are no known bugs in this module.
Please report problems to the address below.
Patches are welcome
=head1 Author
Peter Flanigan, C<< <pjfl@cpan.org> >>
=head1 License and Copyright
Copyright (c) 2016 Peter Flanigan. All rights reserved
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. See L<perlartistic>
This program is distributed in the hope that it will be useful,
but WITHOUT WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE
=cut
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