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package Test::SharedObject;
use 5.008001;
use strict;
use warnings;
our $VERSION = "0.01";
use Storable qw/store_fd fd_retrieve/;
use File::Temp qw/tempfile/;
use Test::SharedObject::Lock;
sub new {
my ($class, $data) = @_;
my ($fh, $file) = tempfile(EXLOCK => 0);
my $self = bless {
file => $file,
ppid => $$,
} => $class;
seek $fh, 0, 0;
truncate $fh, 0;
store_fd \$data, $fh;
close $fh;
return $self;
}
sub txn {
my ($self, $code) = @_;
my $lock = Test::SharedObject::Lock->new($self);
my $fh = $lock->fh;
my $ref = fd_retrieve $fh;
my $data = $code->($$ref);
seek $fh, 0, 0;
truncate $fh, 0;
store_fd \$data, $fh;
return $data; ## unlock
}
sub set {
my ($self, $data) = @_;
return $self->txn(sub { $data });
}
sub _identity { $_[0] }
sub get {
my $self = shift;
return $self->txn(\&_identity);
}
sub DESTROY {
my $self = shift;
unlink $self->{file} if $$ == $self->{ppid};
}
1;
__END__
=encoding utf-8
=head1 NAME
Test::SharedObject - Data sharing in multi process.
=head1 SYNOPSIS
use strict;
use warnings;
use Test::More tests => 2;
use Test::SharedFork;
use Test::SharedObject;
my $shared = Test::SharedObject->new(0);
is $shared->get, 0;
my $pid = fork;
die $! unless defined $pid;
if ($pid == 0) {# child
$shared->txn(sub {
my $counter = shift;
$counter++;
return $counter;
});
exit;
}
wait;
is $shared->get, 1;
=head1 DESCRIPTION
Test::SharedObject provides atomic data operation between multiple process.
=head1 METHODS
=over
=item my $shared = Test::SharedObject->new($value)
Creates a new Test::SharedObject instance.
And set C<$value> as initial value.
Internally, Creates temporary file, and serialize C<$value> by L<Storable>, and save.
=item $shared->txn(\&coderef)
Provides atomic data operation between multiple process in C<\&coderef>.
Set shared value as first arguments in C<\&coderef>, and return value as new shared value.
Internally:
=over
=item Lock temporary file.
=item Read shared value.
=item Executes C<\&coderef>. (Set shared value as first arguments)
=item Write return value as shared value.
=item Unlock temporary file.
=back
Good Example:
$shared->txn(sub {
my $counter = shift;
$counter++; # atomic!!
return $counter;
});
Bad Example:
my $counter;
$shared->txn(sub {
$counter = shift;
});
$counter++; # *NOT* atomic!!
$shared->txn(sub {
return $counter;
});
=item $shared->set($value)
Set C<$value> as shared value.
The syntactic sugar for C<$shared-E<gt>txn()>.
=item my $value = $shared->get()
Get shared value.
The syntactic sugar for C<$shared-E<gt>txn()>.
=back
=head1 LICENSE
Copyright (C) karupanerura.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=head1 AUTHOR
karupanerura E<lt>karupa@cpan.orgE<gt>
=cut
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