<?php
/* -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
# ***** BEGIN LICENSE BLOCK *****
# This file is part of Plume Framework, a simple PHP Application Framework.
# Copyright (C) 2001-2007 Loic d'Anterroches and contributors.
#
# Plume Framework is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# Plume Framework is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#
# ***** END LICENSE BLOCK ***** */

/**
 * APC based cache.
 *
 * You need APC installed on your server for this cache system to
 * work. You can install APC with <code>$ sudo pecl install apc</code>
 * on most systems.
 *
 * A special 'cache_apc_keyprefix' can be set to use APC for different
 * applications and avoid conflict. Compression is performed at the
 * PHP level using the gz(in|de)flate functions.
 *
 * Example of configuration:
 *
 * <pre>
 * $cfg['cache_engine'] = 'Pluf_Cache_Apc';
 * $cfg['cache_timeout'] = 300;
 * $cfg['cache_apc_keyprefix'] = 'uniqueforapp';
 * $cfg['cache_apc_compress'] = true;
 * </pre>
 *
 * @see Pluf_Cache
 * @see http://www.php.net/gzdeflate
 * @see http://www.php.net/gzinflate
 */
class Pluf_Cache_Apc extends Pluf_Cache
{
    /**
     * Prefix added to all the keys.
     */
    private $keyprefix = '';

    /**
     * Auto compress the data to save memory against a small
     * performance loss.
     */
    private $compress = false;

    /**
     * Create the cache object and initialize it from the
     * configuration.
     */
    public function __construct()
    {
        $this->keyprefix = Pluf::f('cache_apc_keyprefix', '');
        $this->compress = Pluf::f('cache_apc_compress', false);
    }

    /**
     * Set a value in the cache.
     *
     * @param string Key to store the information
     * @param mixed Value to store
     * @param int Timeout in seconds (null)
     * @return bool Success
     */
    public function set($key, $value, $timeout=null)
    {
        if ($timeout == null) $timeout = Pluf::f('cache_timeout', 300);
        $value = serialize($value);
        if ($this->compress) $value = gzdeflate($value, 9);
        return apc_store($this->keyprefix.$key, $value, $timeout);
    }

    /**
     * Get value from the cache.
     *
     * @param string Key to get the information
     * @param mixed Default value to return if cache miss (null)
     * @return mixed Stored value or default
     */
    public function get($key, $default=null)
    {
        $success = false;
        $value = apc_fetch($this->keyprefix.$key, &$success);
        if (!$success) return $default;
        if ($this->compress) $value = gzinflate($value);
        return unserialize($value);
    }
}