File Coverage

blib/lib/Vcdiff.pm

Criterion	Covered	Total	%
statement	18	45	40.0
branch	0	10	0.0
condition			n/a
subroutine	6	10	60.0
pod	0	3	0.0
total	24	68	35.2

package Vcdiff;

use strict;

use Symbol;
use Carp;

our $VERSION = '0.505';


## This variable indicates which backend should be used. It should
## be a package name such as "Vcdiff::Xdelta3".

our $backend;


## When new backends are added, this should be updated so that
## the new backend will be probed for.

our @known_backends = qw(
  Vcdiff::Xdelta3
  Vcdiff::OpenVcdiff
);



sub diff {
  _load_backend();

  {
    no strict "refs";
    return qualify("diff", $backend)->(@_);
  }
}

sub patch {
  _load_backend();

  {
    no strict "refs";
    return qualify("patch", $backend)->(@_);
  }
}

sub which_backend {
  _load_backend();

  return $backend;
}

sub _load_backend {

  ## If a backend is set, make sure it's loaded or die trying:

  if (defined $backend) {
    eval "require $backend";
    croak $@ if $@;
    return;
  }

  ## If a backend has already been loaded but not set, set it:

  foreach my $backend_candidate (@known_backends) {
    no strict "refs";
    my $ver = ${qualify("VERSION", $backend_candidate)};
    if (${ qualify("VERSION", $backend_candidate) }) {
      eval "require $backend_candidate";
      next if $@;
      $backend = $backend_candidate;
      return;
    }
  }

  ## Try to find a suitable backend then load and set it:

  foreach my $backend_candidate (@known_backends) {
    eval "require $backend_candidate";

    if (!$@) {
      $backend = $backend_candidate;
      return;
    }
  }

  croak "Unable to find any Vcdiff backend modules (see perldoc Vcdiff)";
}

1;



__END__