[李景山php]thinkphp核心源码注释|Shomp.class.php

<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2014 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------
namespace Think\Cache\Driver;
use Think\Cache;
defined('THINK_PATH') or exit();
/**
* Shmop缓存驱动
* 共享 内存 控制
*/
class Shmop extends Cache {

/**
* 架构函数
* @param array $options 缓存参数
* @access public
*/
public function __construct($options=array()) {
if ( !extension_loaded('shmop') ) {
E(L('_NOT_SUPPORT_').':shmop');
}
if(!empty($options)){
$options = array(
'size'      => C('SHARE_MEM_SIZE'),
'temp'      => TEMP_PATH,
'project'   => 's',
'length'    =>  0,
);
}
$this->options = $options;
$this->options['prefix'] =  isset($options['prefix'])?  $options['prefix']  :   C('DATA_CACHE_PREFIX');
$this->options['length'] =  isset($options['length'])?  $options['length']  :   0;
$this->handler = $this->_ftok($this->options['project']);
}

/**
* 读取缓存
* @access public
* @param string $name 缓存变量名
* @return mixed
*/
public function get($name = false) {
N('cache_read',1); // 记录
$id = shmop_open($this->handler, 'c', 0600, 0);// 打开连接 ，获取资源
if ($id !== false) {
$ret = unserialize(shmop_read($id, 0, shmop_size($id)));
shmop_close($id);// 关闭资料

if ($name === false) {
return $ret;
}
$name   =   $this->options['prefix'].$name; // 规划名字
if(isset($ret[$name])) { // key values
$content   =  $ret[$name];
if(C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
//启用数据压缩
$content   =   gzuncompress($content); // 启动数据压缩
}
return $content;
}else {
return null;
}
}else {
return false;
}
}

/**
* 写入缓存
* @access public
* @param string $name 缓存变量名
* @param mixed $value  存储数据
* @return boolean
*/
public function set($name, $value) {
N('cache_write',1);
$lh = $this->_lock();
$val = $this->get();
if (!is_array($val)) $val = array();
if( C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
//数据压缩
$value   =   gzcompress($value,3);
}
$name   =   $this->options['prefix'].$name;
$val[$name] = $value;
$val = serialize($val);
if($this->_write($val, $lh)) {
if($this->options['length']>0) {
// 记录缓存队列
$this->queue($name);
}
return true;
}
return false;
}

/**
* 删除缓存
* @access public
* @param string $name 缓存变量名
* @return boolean
*/
public function rm($name) {
$lh = $this->_lock();
$val = $this->get();
if (!is_array($val)) $val = array();
$name   =   $this->options['prefix'].$name;
unset($val[$name]);
$val = serialize($val);
return $this->_write($val, $lh);
}

/**
* 生成IPC key
* @access private
* @param string $project 项目标识名
* @return integer
*/
private function _ftok($project) {
if (function_exists('ftok'))   return ftok(__FILE__, $project);
if(strtoupper(PHP_OS) == 'WINNT'){
$s = stat(__FILE__);
return sprintf("%u", (($s['ino'] & 0xffff) | (($s['dev'] & 0xff) << 16) |
(($project & 0xff) << 24)));
}else {
$filename = __FILE__ . (string) $project;
for($key = array(); sizeof($key) < strlen($filename); $key[] = ord(substr($filename, sizeof($key), 1)));
return dechex(array_sum($key));
}
}

/**
* 写入操作
* @access private
* @param string $name 缓存变量名
* @return integer|boolean
* 内部写入操作
*/
private function _write(&$val, &$lh) {
$id  = shmop_open($this->handler, 'c', 0600, $this->options['size']);
if ($id) {
$ret = shmop_write($id, $val, 0) == strlen($val);
shmop_close($id);
$this->_unlock($lh);
return $ret;
}
$this->_unlock($lh);
return false;
}

/**
* 共享锁定
* @access private
* @param string $name 缓存变量名
* @return boolean
* 加锁
*/
private function _lock() {
if (function_exists('sem_get')) {
$fp = sem_get($this->handler, 1, 0600, 1);
sem_acquire ($fp);
} else {
$fp = fopen($this->options['temp'].$this->options['prefix'].md5($this->handler), 'w');
flock($fp, LOCK_EX);
}
return $fp;
}

/**
* 解除共享锁定
* @access private
* @param string $name 缓存变量名
* @return boolean
* 解除共享锁
*/
private function _unlock(&$fp) {
if (function_exists('sem_release')) {
sem_release($fp);
} else {
fclose($fp);
}
}
}
// 总结，更多的作为一个函数的 封装，模块调用。