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lib/Bot/Cobalt/Serializer.pm  view on Meta::CPAN

  my $module;
  return unless $module = $self->_types->{$type};

  {
    local $@;
    eval "require $module";
    return if $@;
  }

  return $module
}


sub _read_serialized {
  my ($self, $path, $opts) = @_;
  return unless defined $path;

  my $lock = 1;
  if (defined $opts && ref $opts && reftype $opts eq 'HASH') {
    $lock = $opts->{Locking} if defined $opts->{Locking};
  }

  if (blessed $path && $path->can('slurp_utf8')) {
    return $path->slurp_utf8
  } else {
    open(my $in_fh, '<:encoding(UTF-8)', $path)
      or confess "open failed for $path: $!";

    if ($lock) {
      flock($in_fh, LOCK_SH)
        or confess "LOCK_SH failed for $path: $!";
     }

    my $data = join '', <$in_fh>;

    flock($in_fh, LOCK_UN) if $lock;

    close($in_fh)
      or carp "close failed for $path: $!";

    return $data
  }
}

sub _write_serialized {
  my ($self, $path, $data, $opts) = @_;
  return unless $path and defined $data;

  my $lock    = 1;
  my $timeout = 2;

  if (defined $opts && ref $opts && reftype $opts eq 'HASH') {
    $lock    = $opts->{Locking} if defined $opts->{Locking};
    $timeout = $opts->{Timeout} if $opts->{Timeout};
  }

  open(my $out_fh, '>>:encoding(UTF-8)', $path)
    or confess "open failed for $path: $!";

  if ($lock) {
    my $timer = 0;

    until ( flock $out_fh, LOCK_EX | LOCK_NB ) {
      confess "Failed writefile lock ($path), timed out ($timeout)"
        if $timer > $timeout;

      sleep 0.01;
      $timer += 0.01;
    }

  }

  seek($out_fh, 0, 0)
    or confess "seek failed for $path: $!";
  truncate($out_fh, 0)
    or confess "truncate failed for $path";

  print $out_fh $data;

  flock($out_fh, LOCK_UN) if $lock;

  close($out_fh)
    or carp "close failed for $path: $!";

  return 1
}

1;
__END__

=pod

=head1 NAME

Bot::Cobalt::Serializer - Bot::Cobalt serialization wrapper

=head1 SYNOPSIS

  use Bot::Cobalt::Serializer;

  ## Spawn a YAML (1.1) handler:
  my $serializer = Bot::Cobalt::Serializer->new;

  ## Spawn a JSON handler:
  my $serializer = Bot::Cobalt::Serializer->new('JSON');
  ## ...same as:
  my $serializer = Bot::Cobalt::Serializer->new( Format => 'JSON' );

  ## Serialize some data to our Format:
  my $ref = { Stuff => { Things => [ 'a', 'b'] } };
  my $frozen = $serializer->freeze( $ref );

  ## Turn it back into a Perl data structure:
  my $thawed = $serializer->thaw( $frozen );

  ## Serialize some $ref to a file at $path
  ## The file will be overwritten
  ## Returns false on failure
  $serializer->writefile( $path, $ref );

  ## Do the same thing, but without locking
  $serializer->writefile( $path, $ref, { Locking => 0 } );

  ## Turn a serialized file back into a $ref
  ## Boolean false on failure
  my $ref = $serializer->readfile( $path );

  ## Do the same thing, but without locking