=pod
=head1 NAME
PPI::Document::Normalized - A normalized Perl Document
=head1 DESCRIPTION
A Normalized Document object is the result of the normalization process
contained in the L<PPI::Normal> class. See its documentation for more
information.
The object contains a version stamp and function list for the version
of L<PPI::Normal> used to create it, and a processed and delinked
L<PPI::Document> object.
Typically, the Document object will have been mangled by the normalization
process in a way that would make it fatal to try to actually DO anything
with it.
Put simply, B<never> use the Document object. B<YOU HAVE BEEN WARNED!>
The object is designed the way it is to provide a bias towards false
negatives. A comparison between to ::Normalized object will only return
true if they were produced by the same version of PPI::Normal, with the
same set of normalization functions (in the same order).
You may get false negatives if you are caching objects across an upgrade.
Please note that this is done for security purposes, as there are many
cases in which low layer normalization is likely to be done as part of
a code security process, and false positives could be highly dangerous.
=head1 METHODS
=cut
use strict;
use UNIVERSAL 'isa';
use overload 'bool' => sub () { 1 },
'==' => 'equal';
use vars qw{$VERSION};
BEGIN {
$VERSION = '1.003';
}
# For convenience (and since this isn't really a public class), import
# the methods we will need from Scalar::Util.
use Scalar::Util 'refaddr',
'reftype',
'blessed';
#####################################################################
# Constructor and Accessors
=pod
=head2 new
The C<new> method is intended for use only by the L<PPI::Normal> class,
and to get ::Normalized objects, you are highly recommended to use
either that module, or the C<normalized> method of the L<PPI::Document>
object itself.
=cut
sub new {
my $class = shift;
my %args = @_;
# Check the required params
my $Document = isa($args{Document}, 'PPI::Document') ? $args{Document} : return undef;
my $version = $args{version} or return undef;
my $functions = ref $args{functions} eq 'ARRAY' ? $args{functions} : return undef;
# Create the object
my $self = bless {
Document => $Document,
version => $version,
functions => $functions,
}, $class;
$self;
}
sub _Document { $_[0]->{Document} }
=pod
=head2 version
The C<version> accessor returns the L<PPI::Normal> version used to create
the object.
=cut
sub version { $_[0]->{version} }
=pod
=head2 functions
The C<functions> accessor returns a reference to an array of the
normalization functions (in order) that were called when creating
the object.
=cut
sub functions { $_[0]->{functions} }
#####################################################################
# Comparison Methods
=pod
=head2 equal $Normalized
The C<equal> method is the primary comparison method, taking another
PPI::Document::Normalized object, and checking for equivalence to it.
The C<==> operator is also overload to this method, so that you can
do something like the following:
my $first = PPI::Document->load('first.pl');
my $second = PPI::Document->load('second.pl');
if ( $first->normalized == $second->normalized ) {
print "The two documents are equivalent";
}
Returns true if the normalized documents are equivalent, false if not,
or C<undef> if there is an error.
=cut
sub equal {
my $self = shift;
my $other = isa(ref $_[0], 'PPI::Document::Normalized') ? shift : return undef;
# Prevent multiple concurrent runs
return undef if $self->{processing};
# Check the version and function list first
return '' unless $self->version == $other->version;
$self->_equal_ARRAY( $self->functions, $other->functions ) or return '';
# Do the main comparison run
$self->{seen} = {};
my $rv = $self->_equal_blessed( $self->_Document, $other->_Document );
delete $self->{seen};
$rv;
}
# Check that two objects are matched
sub _equal_blessed {
my ($self, $this, $that) = @_;
my ($bthis, $bthat) = (blessed $this, blessed $that);
$bthis and $bthat and $bthis eq $bthat or return '';
# Check the object as a reference
$self->_equal_reference( $this, $that );
}
# Check that two references match their types
sub _equal_reference {
my ($self, $this, $that) = @_;
my ($rthis, $rthat) = (refaddr $this, refaddr $that);
$rthis and $rthat or return undef;
# If we have seen this before, are the pointing
# is it the same one we saw in both sides
my $seen = $self->{seen}->{$rthis};
if ( $seen and $seen ne $rthat ) {
return '';
}
# Check the reference types
my ($tthis, $tthat) = (reftype $this, reftype $that);
$tthis and $tthat and $tthis eq $tthat or return undef;
# Check the children of the reference type
$self->{seen}->{$rthis} = $rthat;
my $method = "_equal_$tthat";
my $rv = $self->$method( $this, $that );
delete $self->{seen}->{$rthis};
$rv;
}
# Compare the children of two SCALAR references
sub _equal_SCALAR {
my ($self, $this, $that) = @_;
my ($cthis, $cthat) = ($$this, $$that);
return $self->_equal_blessed( $cthis, $cthat ) if blessed $cthis;
return $self->_equal_reference( $cthis, $cthat ) if ref $cthis;
return (defined $cthat and $cthis eq $cthat) if defined $cthis;
! defined $cthat;
}
# For completeness sake, lets just treat REF as a specialist SCALAR case
sub _equal_REF { shift->_equal_SCALAR(@_) }
# Compare the children of two ARRAY references
sub _equal_ARRAY {
my ($self, $this, $that) = @_;
# Compare the number of elements
scalar(@$this) == scalar(@$that) or return '';
# Check each element in the array.
# Descend depth-first.
foreach my $i ( 0 .. scalar(@$this) ) {
my ($cthis, $cthat) = ($this->[$i], $that->[$i]);
if ( blessed $cthis ) {
return '' unless $self->_equal_blessed( $cthis, $cthat );
} elsif ( ref $cthis ) {
return '' unless $self->_equal_reference( $cthis, $cthat );
} elsif ( defined $cthis ) {
return '' unless (defined $cthat and $cthis eq $cthat);
} else {
return '' if defined $cthat;
}
}
1;
}
# Compare the children of a HASH reference
sub _equal_HASH {
my ($self, $this, $that) = @_;
# Compare the number of keys
return '' unless scalar(keys %$this) == scalar(keys %$that);
# Compare each key, descending depth-first.
foreach my $k ( keys %$this ) {
return '' unless exists $that->{$k};
my ($cthis, $cthat) = ($this->{$k}, $that->{$k});
if ( blessed $cthis ) {
return '' unless $self->_equal_blessed( $cthis, $cthat );
} elsif ( ref $cthis ) {
return '' unless $self->_equal_reference( $cthis, $cthat );
} elsif ( defined $cthis ) {
return '' unless (defined $cthat and $cthis eq $cthat);
} else {
return '' if defined $cthat;
}
}
1;
}
# We do not support GLOB comparisons
sub _equal_GLOB {
my ($self, $this, $that) = @_;
warn('GLOB comparisons are not supported');
'';
}
# We do not support CODE comparisons
sub _equal_CODE {
my ($self, $this, $that) = @_;
refaddr $this == refaddr $that;
}
# We don't support IO comparisons
sub _equal_IO {
my ($self, $this, $that) = @_;
warn('IO comparisons are not supported');
'';
}
sub DESTROY {
# Take the screw up Document with us
if ( $_[0]->{Document} ) {
$_[0]->{Document}->DESTROY;
delete $_[0]->{Document};
}
}
1;
=pod
=head1 SUPPORT
See the L<support section|PPI/SUPPORT> in the main module
=head1 AUTHOR
Adam Kennedy, L<http://ali.as/>, cpan@ali.as
=head1 COPYRIGHT
Copyright (c) 2005 Adam Kennedy. All 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 the license can be found in the
LICENSE file included with this module.
=cut