Cache.php

<?php
/**
 * Cache Class.
 *
 * @package SugiPHP.Cache
 * @author  Plamen Popov <tzappa@gmail.com>
 * @license http://opensource.org/licenses/mit-license.php (MIT License)
 */

namespace SugiPHP\Cache;

class Cache
{
    /**
     * The driver used by a cache.
     * @var StoreInterface
     */
    protected $driver;

    /**
     * Key prefix to use.
     *
     * @var string
     */
    protected $prefix = "";

    /**
     * Class constructor.
     *
     * @param StoreInterface $driver
     */
    public function __construct(StoreInterface $driver)
    {
        $this->driver = $driver;
    }

    /**
     * Sets key prefix.
     *
     * @param string $prefix
     */
    public function setPrefix($prefix)
    {
        $this->prefix = $prefix;
    }

    /**
     * Returns key prefix.
     *
     * @return string
     */
    public function getPrefix()
    {
        return $this->prefix;
    }

    /**
     * Stores an item in the cache for a specified period of time only if it is not already stored.
     * Cache::add() is similar to Cache::set(), but the operation fails if the key already exists.
     *
     * @param string  $key
     * @param mixed  $value The value to be stored.
     * @param integer $ttl Time to live in seconds. 0 means to store it for a maximum time possible
     *
     * @return boolean TRUE if the value is set, FALSE on failure
     */
    public function add($key, $value, $ttl = 0)
    {
        $key = $this->prefix.$key;

        return $this->driver->add($key, $value, $ttl);
    }

    /**
     * Stores an item in the data store
     * Cache::set() is similar to Cache::add(), but the operation will not fail if the key already exist.
     *
     * @param string $key The key under which to store the value
     * @param mixed $value The value to store
     * @param integer $ttl Expiration time in seconds, after which the value is invalidated (deleted)
     *
     * @return boolean TRUE on success or FALSE on failure
     */
    public function set($key, $value, $ttl = 0)
    {
        $key = $this->prefix.$key;

        return $this->driver->set($key, $value, $ttl);
    }

    /**
     * Fetches a stored variable from the cache
     *
     * @param string $key The key used to store the value
     *
     * @return mixed Returns NULL if the key does not exist in the store or the value was expired (see $ttl)
     */
    public function get($key, $defaultValue = null)
    {
        $key = $this->prefix.$key;
        $result = $this->driver->get($key);

        return is_null($result) ? $defaultValue : $result;
    }

    /**
     * Checks if the key exists
     *
     * @param string $key
     *
     * @return boolean TRUE if the key exists, otherwise FALSE
     */
    public function has($key)
    {
        $key = $this->prefix.$key;

        return $this->driver->has($key);
    }

    /**
     * Removes a stored variable from the cache
     *
     * @param string $key
     */
    public function delete($key)
    {
        $key = $this->prefix.$key;

        $this->driver->delete($key);
    }

    /**
     * Invalidate all items in the cache
     */
    public function flush()
    {
        $this->driver->flush();
    }

    /**
     * Increment numeric item's value.
     * If there is no such key or the stored value is not numeric FALSE is returned
     *
     * @param string $key
     * @param integer $step
     *
     * @return integer|false Returns the new incremented value or FALSE on failure
     */
    public function inc($key, $step = 1)
    {
        $key = $this->prefix.$key;

        if ($this->driver instanceof IncrementorInterface) {
            return $this->driver->inc($key, $step);
        }

        $value = $this->driver->get($key);
        if (is_null($value) || !is_numeric($value)) {
            return false;
        }
        $newValue = $value + $step;

        return ($this->driver->set($key, $newValue)) ? $newValue : false;
    }

    /**
     * Decrements numeric item's value.
     * If there is no such key or the stored value is not numeric FALSE is returned
     *
     * @param string $key
     * @param integer $step
     *
     * @return integer|false Returns the new decremented value or FALSE on failure
     */
    public function dec($key, $step = 1)
    {
        $key = $this->prefix.$key;

        if ($this->driver instanceof IncrementorInterface) {
            return $this->driver->dec($key, $step);
        }

        $value = $this->driver->get($key);
        if (is_null($value) || !is_numeric($value)) {
            return false;
        }
        $newValue = $value - $step;

        return ($this->driver->set($key, $newValue)) ? $newValue : false;
    }
}