Yii源码分析之ArrayCache

版权声明：转载请注明来源 https://blog.csdn.net/u013702678/article/details/84311773

ArrayCache仅通过将值存储在数组中来为当前请求提供缓存。

有关ArrayCache支持的常见缓存操作，请参阅yii \ caching \ Cache。

与yii \ caching \ Cache不同，ArrayCache允许set（），add（），multiSet（）和multiAdd（）的expire参数为浮点数，因此您可以指定以毫秒为单位的时间（例如，0.1将为100）毫秒）。

为了增强ArrayCache的性能，可以通过将$ serializer设置为false来禁用存储数据的序列化。

我们看下其源码：

<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\caching;

/**
 * ArrayCache provides caching for the current request only by storing the values in an array.
 *
 * See [[Cache]] for common cache operations that ArrayCache supports.
 *
 * Unlike the [[Cache]], ArrayCache allows the expire parameter of [[set]], [[add]], [[multiSet]] and [[multiAdd]] to
 * be a floating point number, so you may specify the time in milliseconds (e.g. 0.1 will be 100 milliseconds).
 *
 * For enhanced performance of ArrayCache, you can disable serialization of the stored data by setting [[$serializer]] to `false`.
 *
 * For more details and usage information on Cache, see the [guide article on caching](guide:caching-overview).
 *
 * @author Carsten Brandt <[email protected]>
 * @since 2.0
 */
class ArrayCache extends Cache
{
    private $_cache = [];


    /**
     * {@inheritdoc}
     */
    public function exists($key)
    {
        $key = $this->buildKey($key);
        return isset($this->_cache[$key]) && ($this->_cache[$key][1] === 0 || $this->_cache[$key][1] > microtime(true));
    }

    /**
     * {@inheritdoc}
     */
    protected function getValue($key)
    {
        if (isset($this->_cache[$key]) && ($this->_cache[$key][1] === 0 || $this->_cache[$key][1] > microtime(true))) {
            return $this->_cache[$key][0];
        }

        return false;
    }

    /**
     * {@inheritdoc}
     */
    protected function setValue($key, $value, $duration)
    {
        $this->_cache[$key] = [$value, $duration === 0 ? 0 : microtime(true) + $duration];
        return true;
    }

    /**
     * {@inheritdoc}
     */
    protected function addValue($key, $value, $duration)
    {
        if (isset($this->_cache[$key]) && ($this->_cache[$key][1] === 0 || $this->_cache[$key][1] > microtime(true))) {
            return false;
        }
        $this->_cache[$key] = [$value, $duration === 0 ? 0 : microtime(true) + $duration];
        return true;
    }

    /**
     * {@inheritdoc}
     */
    protected function deleteValue($key)
    {
        unset($this->_cache[$key]);
        return true;
    }

    /**
     * {@inheritdoc}
     */
    protected function flushValues()
    {
        $this->_cache = [];
        return true;
    }
}