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|
############################################################################
#
# PostgresVersion.pm
#
# Module encapsulating Postgres Version numbers
#
# Copyright (c) 2021, PostgreSQL Global Development Group
#
############################################################################
=pod
=head1 NAME
PostgresVersion - class representing PostgreSQL version numbers
=head1 SYNOPSIS
use PostgresVersion;
my $version = PostgresVersion->new($version_arg);
# compare two versions
my $bool = $version1 <= $version2;
# or compare with a number
$bool = $version < 12;
# or with a string
$bool = $version lt "13.1";
# interpolate in a string
my $stringyval = "version: $version";
=head1 DESCRIPTION
PostgresVersion encapsulates Postgres version numbers, providing parsing
of common version formats and comparison operations.
=cut
package PostgresVersion;
use strict;
use warnings;
use Scalar::Util qw(blessed);
use overload
'<=>' => \&_version_cmp,
'cmp' => \&_version_cmp,
'""' => \&_stringify;
=pod
=head1 METHODS
=over
=item PostgresVersion->new($version)
Create a new PostgresVersion instance.
The argument can be a number like 12, or a string like '12.2' or the output
of a Postgres command like `psql --version` or `pg_config --version`;
=back
=cut
sub new
{
my $class = shift;
my $arg = shift;
chomp $arg;
# Accept standard formats, in case caller has handed us the output of a
# postgres command line tool
my $devel;
($arg, $devel) = ($1, $2)
if (
$arg =~ m!^ # beginning of line
(?:\(?PostgreSQL\)?\s)? # ignore PostgreSQL marker
(\d+(?:\.\d+)*) # version number, dotted notation
(devel|(?:alpha|beta|rc)\d+)? # dev marker - see version_stamp.pl
!x);
# Split into an array
my @numbers = split(/\./, $arg);
# Treat development versions as having a minor/micro version one less than
# the first released version of that branch.
push @numbers, -1 if ($devel);
$devel ||= "";
return bless { str => "$arg$devel", num => \@numbers }, $class;
}
# Routine which compares the _pg_version_array obtained for the two
# arguments and returns -1, 0, or 1, allowing comparison between two
# PostgresVersion objects or a PostgresVersion and a version string or number.
#
# If the second argument is not a blessed object we call the constructor
# to make one.
#
# Because we're overloading '<=>' and 'cmp' this function supplies us with
# all the comparison operators ('<' and friends, 'gt' and friends)
#
sub _version_cmp
{
my ($a, $b, $swapped) = @_;
$b = __PACKAGE__->new($b) unless blessed($b);
($a, $b) = ($b, $a) if $swapped;
my ($an, $bn) = ($a->{num}, $b->{num});
for (my $idx = 0;; $idx++)
{
return 0 unless (defined $an->[$idx] && defined $bn->[$idx]);
return $an->[$idx] <=> $bn->[$idx]
if ($an->[$idx] <=> $bn->[$idx]);
}
}
# Render the version number using the saved string.
sub _stringify
{
my $self = shift;
return $self->{str};
}
1;
|
