File: //var/cpanel/perl/easy/Cpanel/CPAN/Data/Compare.pm
# Cpanel::CPAN::Data::Compare - compare perl data structures
# Author: Fabien Tassin <fta@sofaraway.org>
# updated by David Cantrell <david@cantrell.org.uk>
# Copyright 1999-2001 Fabien Tassin <fta@sofaraway.org>
# portions Copyright 2003 - 2007 David Cantrell
package Cpanel::CPAN::Data::Compare;
use strict;
use warnings;
use vars qw(@ISA @EXPORT $VERSION $DEBUG %been_there);
use Exporter;
use Carp;
@ISA = qw(Exporter);
@EXPORT = qw(Compare);
$VERSION = '0.17';
$DEBUG = 0;
my %handler;
sub import {
use Cwd; # if this is the only use of it, then require it here instead
if ( eval { chdir( getcwd() ) } ) { # chdir(getcwd()) is Bad in taint mode
_register_plugins();
}
}
# finds and registers plugins
sub _register_plugins {
require File::Find::Rule; # do it here so _register_plugins can be called
foreach my $file (
File::Find::Rule->file()->name('*.pm')->in(
map { "$_/Data/Compare/Plugins" }
grep { -d "$_/Data/Compare/Plugins" } @INC
)
) {
# all of this just to avoid loading the same plugin twice and
# generating a pile of warnings. Grargh!
$file =~ s!.*(Data/Compare/Plugins/.*)\.pm$!$1!;
$file =~ s!/!::!g;
# ignore badly named example from earlier version, oops
next if ( $file eq 'Cpanel::CPAN::Data::Compare::Plugins::Scalar-Properties' );
my $requires = eval "require $file";
next if ( $requires eq '1' ); # already loaded this plugin?
# not an arrayref? bail
if ( ref($requires) ne 'ARRAY' ) {
warn("$file isn't a valid Cpanel::CPAN::Data::Compare plugin (didn't return arrayref)\n");
return;
}
# coerce into arrayref of arrayrefs if necessary
if ( ref( ( @{$requires} )[0] ) ne 'ARRAY' ) { $requires = [$requires] }
# register all the handlers
foreach my $require ( @{$requires} ) {
my ( $handler, $type1, $type2, $cruft ) = reverse @{$require};
$type2 = $type1 unless ( defined($type2) );
( $type1, $type2 ) = sort( $type1, $type2 );
if ( !defined($type1) || ref($type1) ne '' || !defined($type2) || ref($type2) ne '' ) {
warn("$file isn't a valid Cpanel::CPAN::Data::Compare plugin (invalid type)\n");
}
elsif ( defined($cruft) ) {
warn("$file isn't a valid Cpanel::CPAN::Data::Compare plugin (extra data)\n");
}
elsif ( ref($handler) ne 'CODE' ) {
warn("$file isn't a valid Cpanel::CPAN::Data::Compare plugin (no coderef)\n");
}
else {
$handler{$type1}{$type2} = $handler;
}
}
}
}
sub Compare ($$;$);
sub new {
my $this = shift;
my $class = ref($this) || $this;
my $self = {};
bless $self, $class;
$self->{'x'} = shift;
$self->{'y'} = shift;
return $self;
}
sub Cmp ($;$$) {
my $self = shift;
croak "Usage: DataCompareObj->Cmp(x, y)" unless $#_ == 1 || $#_ == -1;
my $x = shift || $self->{'x'};
my $y = shift || $self->{'y'};
return Compare( $x, $y );
}
sub Compare ($$;$) {
croak "Usage: Cpanel::CPAN::Data::Compare::Compare(x, y, [opts])\n" unless $#_ == 1 || $#_ == 2;
my $x = shift @_;
my $y = shift @_;
my $opts = ( shift @_ ) || {};
my $rval = '';
if ( !exists( $opts->{recursion_detector} ) ) {
%been_there = ();
$opts->{recursion_detector} = 0;
}
$opts->{recursion_detector}++;
warn "Yaroo! deep recursion!\n" if ( $opts->{recursion_detector} == 99 );
if ( ( ref($x) && exists( $been_there{$x} ) && $been_there{$x} > 1 )
|| ( ref($y) && exists( $been_there{$y} ) && $been_there{$y} > 1 ) ) {
$rval = 0; # is this the right thing to do?
}
else {
$been_there{$x}++ if ( ref($x) );
$been_there{$y}++ if ( ref($y) );
$opts->{ignore_hash_keys} = { map { ( $_, 1 ) } @{ $opts->{ignore_hash_keys} } } if ( ref( $opts->{ignore_hash_keys} ) eq 'ARRAY' );
my $refx = ref $x;
my $refy = ref $y;
if ( exists( $handler{$refx} ) && exists( $handler{$refx}{$refy} ) ) {
$rval = &{ $handler{$refx}{$refy} }( $x, $y, $opts );
}
elsif ( exists( $handler{$refy} ) && exists( $handler{$refy}{$refx} ) ) {
$rval = &{ $handler{$refy}{$refx} }( $x, $y, $opts );
}
elsif ( !$refx && !$refy ) { # both are scalars
if ( defined $x && defined $y ) { # both are defined
$rval = $x eq $y;
}
else { $rval = !( defined $x || defined $y ); }
}
elsif ( $refx ne $refy ) { # not the same type
$rval = 0;
}
elsif ( $x == $y ) { # exactly the same reference
$rval = 1;
}
elsif ( $refx eq 'SCALAR' || $refx eq 'REF' ) {
$rval = Compare( $$x, $$y, $opts );
}
elsif ( $refx eq 'ARRAY' ) {
if ( $#$x == $#$y ) { # same length
my $i = -1;
$rval = 1;
for (@$x) {
$i++;
$rval = 0 unless Compare( $$x[$i], $$y[$i], $opts );
}
}
else {
$rval = 0;
}
}
elsif ( $refx eq 'HASH' ) {
my @kx = grep { !$opts->{ignore_hash_keys}->{$_} } keys %$x;
my @ky = grep { !$opts->{ignore_hash_keys}->{$_} } keys %$y; # heh, KY
$rval = 1;
$rval = 0 unless scalar @kx == scalar @ky;
for (@kx) {
next unless defined $$x{$_} || defined $$y{$_};
$rval = 0 unless defined $$y{$_} && Compare( $$x{$_}, $$y{$_}, $opts );
}
}
elsif ( $refx eq 'Regexp' ) {
$rval = Compare( $x . '', $y . '', $opts );
}
elsif ( $refx eq 'CODE' ) {
$rval = 0;
}
elsif ( $refx eq 'GLOB' ) {
$rval = 0;
}
else { # a package name (object blessed)
my ($type) = "$x" =~ m/^$refx=(\S+)\(/;
if ( $type eq 'HASH' ) {
my %x = %$x;
my %y = %$y;
$rval = Compare( \%x, \%y, $opts );
$been_there{ \%x }--; # decrement count for temp structures
$been_there{ \%y }--;
}
elsif ( $type eq 'ARRAY' ) {
my @x = @$x;
my @y = @$y;
$rval = Compare( \@x, \@y, $opts );
$been_there{ \@x }--;
$been_there{ \@y }--;
}
elsif ( $type eq 'SCALAR' || $type eq 'REF' ) {
my $x = $$x;
my $y = $$y;
$rval = Compare( $x, $y, $opts );
# $been_there{\$x}--;
# $been_there{\$y}--;
}
elsif ( $type eq 'GLOB' ) {
$rval = 0;
}
elsif ( $type eq 'CODE' ) {
$rval = 0;
}
else {
$rval = 0;
croak "Can't handle $type type.";
}
}
}
$opts->{recursion_detector}--;
return $rval;
}
sub plugins {
return {
map {
( ( $_ eq '' ) ? '[scalar]' : $_, [ map { $_ eq '' ? '[scalar]' : $_ } keys %{ $handler{$_} } ] )
} keys %handler
};
}
sub plugins_printable {
my $r = "The following comparisons are available through plugins\n\n";
foreach my $key ( sort keys %handler ) {
foreach ( sort keys %{ $handler{$key} } ) {
$r .= join( ":\t", map { $_ eq '' ? '[scalar]' : $_ } ( $key, $_ ) ) . "\n";
}
}
return $r;
}
1;
=head1 NAME
Cpanel::CPAN::Data::Compare - compare perl data structures
=head1 SYNOPSIS
use Cpanel::CPAN::Data::Compare;
my $h1 = { 'foo' => [ 'bar', 'baz' ], 'FOO' => [ 'one', 'two' ] };
my $h2 = { 'foo' => [ 'bar', 'barf' ], 'FOO' => [ 'one', 'two' ] };
my @a1 = ('one', 'two');
my @a2 = ('bar', 'baz');
my %v = ( 'FOO', \@a1, 'foo', \@a2 );
# simple procedural interface
print 'structures of $h1 and \%v are ',
Compare($h1, \%v) ? "" : "not ", "identical.\n";
print 'structures of $h1 and $h2 are ',
Compare($h1, $h2, { ignore_hash_keys => [qw(foo)] }) ? '' : 'not ',
"close enough to identical.\n";
# OO usage
my $c = new Cpanel::CPAN::Data::Compare($h1, \%v);
print 'structures of $h1 and \%v are ',
$c->Cmp ? "" : "not ", "identical.\n";
# or
my $c = new Cpanel::CPAN::Data::Compare;
print 'structures of $h and \%v are ',
$c->Cmp($h1, \%v) ? "" : "not ", "identical.\n";
=head1 DESCRIPTION
Compare two perl data structures recursively. Returns 0 if the
structures differ, else returns 1.
A few data types are treated as special cases:
=over 4
=item Scalar::Properties objects
This has been moved into a plugin, although functionality remains the
same as with the previous version. Full documentation is in
L<Cpanel::CPAN::Data::Compare::Plugins::Scalar::Properties>.
=item Compiled regular expressions, eg qr/foo/
These are stringified before comparison, so the following will match:
$r = qr/abc/i;
$s = qr/abc/i;
Compare($r, $s);
and the following won't, despite them matching *exactly* the same text:
$r = qr/abc/i;
$s = qr/[aA][bB][cC]/;
Compare($r, $s);
Sorry, that's the best we can do.
=item CODE and GLOB references
These are assumed not to match unless the references are identical - ie,
both are references to the same thing.
=back
You may also customise how we compare structures by supplying options in
a hashref as a third parameter to the C<Compare()> function. This is not
yet available through the OO-ish interface. These options will be in
force for the *whole* of your comparison, so will apply to structures
that are lurking deep down in your data as well as at the top level, so
beware!
=over 4
=item ignore_hash_keys
an arrayref of strings. When comparing two hashes, any keys mentioned in
this list will be ignored.
=back
=head1 CIRCULAR STRUCTURES
Comparing a circular structure to itself returns true:
$x = \$y;
$y = \$x;
Compare([$x, $y], [$x, $y]);
But comparing two different circular structures returns false:
$x = \$y;
$y = \$x;
Compare([$x, $y], [$y, $x]); # <-- note different order
And on a sort-of-related note, if you try to compare insanely deeply nested
structures, the module will spit a warning. For this to affect you, you need to go
around a hundred levels deep though, and if you do that you have bigger
problems which I can't help you with ;-)
=head1 PLUGINS
The module takes plug-ins so you can provide specialised routines for
comparing your own objects and data-types. For details see
L<Cpanel::CPAN::Data::Compare::Plugins>.
Plugins are *not* available when running in "taint" mode.
A couple of functions are provided to examine what goodies have been
made available through plugins:
=over 4
=item plugins
Returns a structure (a hash ref) describing all the comparisons made
available through plugins.
This function is *not* exported, so should be called as Cpanel::CPAN::Data::Compare::plugins().
It takes no parameters.
=item plugins_printable
Returns formatted text
=back
=head1 BUGS
Plugin support is not quite finished (see the TODO file for details) but
is usable. The missing bits are bells and whistles rather than core
functionality.
Plugins are unavailable if you can't change to the current directory. This
might happen if you started your process as a priveleged user and then
dropped priveleges. This is due to how we check for Taintedness. If this
affects you, please supply a portable patch.
=head1 AUTHOR
Fabien Tassin E<lt>fta@sofaraway.orgE<gt>
Portions by David Cantrell E<lt>david@cantrell.org.ukE<gt>
=head1 COPYRIGHT and LICENCE
Copyright (c) 1999-2001 Fabien Tassin. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
Some parts copyright 2003 - 2007 David Cantrell.
Seeing that Fabien seems to have disappeared, David Cantrell has become
a co-maintainer so he can apply needed patches. The licence, of course,
remains the same, and all communications about this module should be
CCed to Fabien in case he ever returns and wants his baby back.
=head1 SEE ALSO
perl(1), perlref(1)
=cut