<?php

/**
 * @package KantPHP
 * @author  Zhenqiang Zhang <zhenqiang.zhang@hotmail.com>
 * @copyright (c) KantPHP Studio, All rights reserved.
 * @license http://www.opensource.org/licenses/BSD-3-Clause  The BSD 3-Clause License
 */
namespace Kant\Caching;

/**
 * WinCache provides Windows Cache caching in terms of an application component.
 *
 * To use this application component, the [WinCache PHP extension](http://www.iis.net/expand/wincacheforphp)
 * must be loaded. Also note that "wincache.ucenabled" should be set to "On" in your php.ini file.
 *
 * See [[Cache]] manual for common cache operations that are supported by WinCache.
 *
 * For more details and usage information on Cache, see the [guide article on caching](guide:caching-overview).
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class WinCache extends Cache
{

    /**
     * Checks whether a specified key exists in the cache.
     * This can be faster than getting the value from the cache if the data is big.
     * Note that this method does not check whether the dependency associated
     * with the cached data, if there is any, has changed. So a call to [[get]]
     * may return false while exists returns true.
     * 
     * @param mixed $key
     *            a key identifying the cached value. This can be a simple string or
     *            a complex data structure consisting of factors representing the key.
     * @return bool true if a value exists in cache, false if the value is not in the cache or expired.
     */
    public function exists($key)
    {
        $key = $this->buildKey($key);
        
        return wincache_ucache_exists($key);
    }

    /**
     * Retrieves a value from cache with a specified key.
     * This is the implementation of the method declared in the parent class.
     * 
     * @param string $key
     *            a unique key identifying the cached value
     * @return string|bool the value stored in cache, false if the value is not in the cache or expired.
     */
    protected function getValue($key)
    {
        return wincache_ucache_get($key);
    }

    /**
     * Retrieves multiple values from cache with the specified keys.
     * 
     * @param array $keys
     *            a list of keys identifying the cached values
     * @return array a list of cached values indexed by the keys
     */
    protected function getValues($keys)
    {
        return wincache_ucache_get($keys);
    }

    /**
     * Stores a value identified by a key in cache.
     * This is the implementation of the method declared in the parent class.
     *
     * @param string $key
     *            the key identifying the value to be cached
     * @param mixed $value
     *            the value to be cached. Most often it's a string. If you have disabled [[serializer]],
     *            it could be something else.
     * @param int $duration
     *            the number of seconds in which the cached value will expire. 0 means never expire.
     * @return bool true if the value is successfully stored into cache, false otherwise
     */
    protected function setValue($key, $value, $duration)
    {
        return wincache_ucache_set($key, $value, $duration);
    }

    /**
     * Stores multiple key-value pairs in cache.
     * 
     * @param array $data
     *            array where key corresponds to cache key while value is the value stored
     * @param int $duration
     *            the number of seconds in which the cached values will expire. 0 means never expire.
     * @return array array of failed keys
     */
    protected function setValues($data, $duration)
    {
        return wincache_ucache_set($data, null, $duration);
    }

    /**
     * Stores a value identified by a key into cache if the cache does not contain this key.
     * This is the implementation of the method declared in the parent class.
     *
     * @param string $key
     *            the key identifying the value to be cached
     * @param mixed $value
     *            the value to be cached. Most often it's a string. If you have disabled [[serializer]],
     *            it could be something else.
     * @param int $duration
     *            the number of seconds in which the cached value will expire. 0 means never expire.
     * @return bool true if the value is successfully stored into cache, false otherwise
     */
    protected function addValue($key, $value, $duration)
    {
        return wincache_ucache_add($key, $value, $duration);
    }

    /**
     * Adds multiple key-value pairs to cache.
     * The default implementation calls [[addValue()]] multiple times add values one by one. If the underlying cache
     * storage supports multiadd, this method should be overridden to exploit that feature.
     * 
     * @param array $data
     *            array where key corresponds to cache key while value is the value stored
     * @param int $duration
     *            the number of seconds in which the cached values will expire. 0 means never expire.
     * @return array array of failed keys
     */
    protected function addValues($data, $duration)
    {
        return wincache_ucache_add($data, null, $duration);
    }

    /**
     * Deletes a value with the specified key from cache
     * This is the implementation of the method declared in the parent class.
     * 
     * @param string $key
     *            the key of the value to be deleted
     * @return bool if no error happens during deletion
     */
    protected function deleteValue($key)
    {
        return wincache_ucache_delete($key);
    }

    /**
     * Deletes all values from cache.
     * This is the implementation of the method declared in the parent class.
     * 
     * @return bool whether the flush operation was successful.
     */
    protected function flushValues()
    {
        return wincache_ucache_clear();
    }
}
