##############################################################################
# $URL: http://perlcritic.tigris.org/svn/perlcritic/trunk/distributions/Perl-Critic/lib/Perl/Critic/Policy/InputOutput/ProhibitJoinedReadline.pm $
# $Date: 2013-09-25 22:21:28 -0700 (Wed, 25 Sep 2013) $
# $Author: thaljef $
# $Revision: 4171 $
##############################################################################
package Perl::Critic::Policy::InputOutput::ProhibitJoinedReadline;
use 5.006001;
use strict;
use warnings;
use Readonly;
use List::MoreUtils qw(any);
use Perl::Critic::Utils qw{ :severities :classification parse_arg_list };
use base 'Perl::Critic::Policy';
our $VERSION = '1.119';
#-----------------------------------------------------------------------------
Readonly::Scalar my $DESC => q{Use "local $/ = undef" or File::Slurp instead of joined readline}; ## no critic qw(InterpolationOfMetachars)
Readonly::Scalar my $EXPL => [213];
#-----------------------------------------------------------------------------
sub supported_parameters { return () }
sub default_severity { return $SEVERITY_MEDIUM }
sub default_themes { return qw( core pbp performance ) }
sub applies_to { return 'PPI::Token::Word' }
#-----------------------------------------------------------------------------
sub violates {
my ( $self, $elem, undef ) = @_;
return if $elem ne 'join';
return if ! is_function_call($elem);
my @args = parse_arg_list($elem);
shift @args; # ignore separator string
if (any { any { $_->isa('PPI::Token::QuoteLike::Readline') } @{$_} } @args) {
return $self->violation( $DESC, $EXPL, $elem );
}
return; # OK
}
1;
__END__
#-----------------------------------------------------------------------------
=pod
=head1 NAME
Perl::Critic::Policy::InputOutput::ProhibitJoinedReadline - Use C<local $/ = undef> or L<File::Slurp|File::Slurp> instead of joined readline.
=head1 AFFILIATION
This Policy is part of the core L<Perl::Critic|Perl::Critic>
distribution.
=head1 DESCRIPTION
It's really easy to slurp a whole filehandle in at once with C<join
q{}, <$fh>>, but that's inefficient -- Perl goes to the trouble of
splitting the file into lines only to have that work thrown away.
To save performance, either slurp the filehandle without splitting
like so:
do { local $/ = undef; <$fh> }
or use L<File::Slurp|File::Slurp>, which is even faster.
B<Note> that if the C<ProhibitPunctuationVars> policy is also in effect,
it will complain about the use of C<$/> in the line above. In that
case, write this instead:
use English '-no_match_vars';
do { local $INPUT_RECORD_SEPARATOR = undef; <$fh> };
=head1 CONFIGURATION
This Policy is not configurable except for the standard options.
=head1 CAVEATS
Due to a bug in the current version of PPI (v1.119_03) and earlier,
the readline operator is often misinterpreted as less-than and
greater-than operators after a comma. Therefore, this policy only
works well on the empty filehandle, C<< <> >>. When PPI is fixed,
this should just start working.
=head1 CREDITS
Initial development of this policy was supported by a grant from the
Perl Foundation.
=head1 AUTHOR
Chris Dolan <cdolan@cpan.org>
=head1 COPYRIGHT
Copyright (c) 2007-2011 Chris Dolan. Many rights reserved.
This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself. The full text of this license
can be found in the LICENSE file included with this module
=cut
# Local Variables:
# mode: cperl
# cperl-indent-level: 4
# fill-column: 78
# indent-tabs-mode: nil
# c-indentation-style: bsd
# End:
# ex: set ts=8 sts=4 sw=4 tw=78 ft=perl expandtab shiftround :