# Movable Type (r) Open Source (C) 2001-2010 Six Apart Ltd.
# This program is distributed under the terms of the
# GNU General Public License, version 2.
#
# $Id: CacheWrapper.pm 5144 2010-01-06 05:49:46Z takayama $

package MT::ObjectDriver::Driver::CacheWrapper;

use strict;
use MT;

my $CACHE_ENABLED;
sub wrap {
    my $class = shift;
    my($fallback, $object_class) = @_;

    # prevent caching if so configured
    unless (defined $CACHE_ENABLED) {
        $CACHE_ENABLED = MT->config->DisableObjectCache ? 0 : 1;
    }
    my $use_caching = 1;
    if ($CACHE_ENABLED && $object_class) {
        if (my $props = $object_class->properties) {
            $use_caching = 0 if (defined $props->{cacheable}) && (!$props->{cacheable});
        }
    }
    elsif (!$CACHE_ENABLED) {
        $use_caching = 0;
    }

    if ( $use_caching ) {
        ## If running under mod_perl, using request->pnotes; otherwise,
        ## just use a hash.
        my $ram_cache;
        if ($ENV{MOD_PERL}) {
            require Data::ObjectDriver::Driver::Cache::Apache;
            $ram_cache = 'Data::ObjectDriver::Driver::Cache::Apache';
        } else {
            require MT::ObjectDriver::Driver::Cache::RAM;
            $ram_cache = 'MT::ObjectDriver::Driver::Cache::RAM';
        }

        my $driver;

        require MT::Memcached;
        if (MT::Memcached->is_available) {
            $driver = sub {
                ## Look first in mod_perl/memory; then in memcached; then fall back
                ## to hitting the database.
                require Data::ObjectDriver::Driver::Cache::Memcached;
                $ram_cache->new(
                    fallback =>
                        Data::ObjectDriver::Driver::Cache::Memcached->new(
                            cache    => MT::Memcached->instance,
                            fallback => $fallback->(),
                        )
                );
            };
        } else {
            $driver = sub {
                return $ram_cache->new(
                    fallback => $fallback->(),
                );
            };
        }
        return $driver;
    } else {
        return $fallback;
    }
}

1;
