Implementation code of apc and file cache classes in php-PHP Tutorial-php.cn

class CacheException extends Exception {}
/**
* Cache abstract class
*/
abstract class Cache_Abstract {
/**
* Read cache variable
*
* @param string $key cache subscript
* @return mixed
*/
abstract public function fetch($key);
/**
* Cache variable
*
* @param string $key cache variable subscript
* @param string $value cache variable value
* @return bool
*/
abstract public function store($key, $value);
/**
* Delete cache variables
*
* @param string $key cache subscript
* @return Cache_Abstract
*/
abstract public function delete($key);
/**
* Clear (delete) all caches
*
* @return Cache_Abstract
*/
abstract public function clear();
/**
* Lock cache variable
*
* @param string $key cache subscript
* @return Cache_Abstract
*/
abstract public function lock($key);
/**
* Cache variable unlock
*
* @param string $key cache subscript
* @return Cache_Abstract
*/
abstract public function unlock($key);
/**
* Get whether the cache variable is locked
*
* @param string $key cache subscript
* @return bool
*/
abstract public function isLocked($key);
/**
* Make sure it is not locked
* Sleep at most $tries times to wait for unlocking, skip and unlock after timeout
*
* @param string $key cache subscript
*/
public function checkLock($key) {
if (!$this->isLocked($key)) {
return $this;
}
$tries = 10;
$count = 0;
do {
usleep(200);
$count ++;
} while ($count <= $tries && $this->isLocked($key)); // 最多做十次睡眠等待解锁，超时则跳过并解锁
$this->isLocked($key) && $this->unlock($key);
return $this;
}
}
/**
* APC extended cache implementation
*
* @by bbs.it-home.org
* @category Mjie
* @package Cache
* @license New BSD License
* @version $Id: Cache/Apc.php version number 2010-04-18 23:02 cmpan $
*/
class Cache_Apc extends Cache_Abstract {
protected $_prefix = 'cache.mjie.net';
public function __construct() {
if (!function_exists('apc_cache_info')) {
throw new CacheException('apc extension didn't installed');
}
}
/**
* Save cache variables
*
* @param string $key
* @param mixed $value
* @return bool
*/
public function store($key, $value) {
return apc_store($this->_storageKey($key), $value);
}
/**
* Read cache
*
* @param string $key
* @return mixed
*/
public function fetch($key) {
return apc_fetch($this->_storageKey($key));
}
/**
* Clear cache
*
* @return Cache_Apc
*/
public function clear() {
apc_clear_cache();
return $this;
}
/**
* Delete cache unit
*
* @return Cache_Apc
*/
public function delete($key) {
apc_delete($this->_storageKey($key));
return $this;
}
/**
* Whether the cache unit is locked
*
* @param string $key
* @return bool
*/
public function isLocked($key) {
if ((apc_fetch($this->_storageKey($key) . '.lock')) === false) {
return false;
}
return true;
}
/**
* Lock cache unit
*
* @param string $key
* @return Cache_Apc
*/
public function lock($key) {
apc_store($this->_storageKey($key) . '.lock', '', 5);
return $this;
}
/**
* Cache unit unlock
*
* @param string $key
* @return Cache_Apc
*/
public function unlock($key) {
apc_delete($this->_storageKey($key) . '.lock');
return $this;
}
/**
*Full cache name
*
* @param string $key
* @return string
*/
private function _storageKey($key) {
return $this->_prefix . '_' . $key;
}
}
/**
* File cache implementation
*
* @by bbs.it-home.org
* @category Mjie
* @package Cache
* @license New BSD License
* @version $Id: Cache/File.php version number 2010 -04-18 16:46 cmpan $
*/
class Cache_File extends Cache_Abstract {
protected $_cachesDir = 'cache';
public function __construct() {
if (defined('DATA_DIR')) {
$this->_setCacheDir(DATA_DIR . '/cache');
}
}
/**
* Get cache file
*
* @param string $key
* @return string
*/
protected function _getCacheFile($key) {
return $this->_cachesDir . '/' . substr($key, 0, 2) . '/' . $key . '.php';
}
/**
* Read cache variables
* To prevent information leakage, the cache file format is a php file and starts with ""
*
* @param string $key cache subscript
* @return mixed
*/
public function fetch($key) {
$cacheFile = self::_getCacheFile($key);
if (file_exists($cacheFile) && is_readable($cacheFile)) {
return unserialize(@file_get_contents($cacheFile, false, NULL, 13));
}
return false;
}
/**
* Cache variable
* To prevent information leakage, the cache file format is a php file and starts with ""
*
* @param string $key cache variable subscript
* @param string $value The value of the cache variable
* @return bool
*/
public function store($key, $value) {
$cacheFile = self::_getCacheFile($key);
$cacheDir = dirname($cacheFile);
if(!is_dir($cacheDir)) {
if([url=mailto:!@mkdir($cacheDir]!@mkdir($cacheDir[/url], 0755, true)) {
throw new CacheException("Could not make cache directory");
}
}
return @file_put_contents($cacheFile, '' . serialize($value));
}
/**
* Delete cache variable
*
* @param string $key cache subscript
* @return Cache_File
*/
public function delete($key) {
if(empty($key)) {
throw new CacheException("Missing argument 1 for Cache_File::delete()");
}
$cacheFile = self::_getCacheFile($key);
if([url=mailto:!@unlink($cacheFile]!@unlink($cacheFile[/url])) {
throw new CacheException("Cache file could not be deleted");
}
return $this;
}
/**
* Whether the cache unit is locked
*
* @param string $key
* @return bool
*/
public function isLocked($key) {
$cacheFile = self::_getCacheFile($key);
clearstatcache();
return file_exists($cacheFile . '.lock');
}
/**
* Lock
*
* @param string $key
* @return Cache_File
*/
public function lock($key) {
$cacheFile = self::_getCacheFile($key);
$cacheDir = dirname($cacheFile);
if(!is_dir($cacheDir)) {
if([url=mailto:!@mkdir($cacheDir]!@mkdir($cacheDir[/url], 0755, true)) {
if(!is_dir($cacheDir)) {
throw new CacheException("Could not make cache directory");
}
}
}
// 设定缓存锁文件的访问和修改时间
@touch($cacheFile . '.lock');
return $this;
}
/**
* Unlock
*
* @param string $key
* @return Cache_File
*/
public function unlock($key) {
$cacheFile = self::_getCacheFile($key);
@unlink($cacheFile . '.lock');
return $this;
}
/**
* Set the file cache directory
* @param string $dir
* @return Cache_File
*/
protected function _setCacheDir($dir) {
$this->_cachesDir = rtrim(str_replace('\', '/', trim($dir)), '/');
clearstatcache();
if(!is_dir($this->_cachesDir)) {
mkdir($this->_cachesDir, 0755, true);
}
//
return $this;
}
/**
* Clear all caches
*
* @return Cache_File
*/
public function clear() {
// 遍历目录清除缓存
$cacheDir = $this->_cachesDir;
$d = dir($cacheDir);
while(false !== ($entry = $d->read())) {
if('.' == $entry[0]) {
continue;
}
$cacheEntry = $cacheDir . '/' . $entry;
if(is_file($cacheEntry)) {
@unlink($cacheEntry);
} elseif(is_dir($cacheEntry)) {
// 缓存文件夹有两级
$d2 = dir($cacheEntry);
while(false !== ($entry = $d2->read())) {
if('.' == $entry[0]) {
continue;
}
$cacheEntry .= '/' . $entry;
if(is_file($cacheEntry)) {
@unlink($cacheEntry);
}
}
$d2->close();
}
}
$d->close();
return $this;
}
}
/**
* Data structure of cache unit
* array(
* 'time' => time(), // Timestamp when cache is written
* 'expire' => $expire, // Cache expiration time
* 'valid' => true, // Whether the cache is valid
* 'data' => $value // The cached value
* );
*/
final class Cache {
/**
* Cache expiration time length (s)
*
* @var int
*/
private $_expire = 3600;
/**
* Cache processing class
*
* @var Cache_Abstract
*/
private $_storage = null;
/**
* @return Cache
*/
static public function createCache($cacheClass = 'Cache_File') {
return new self($cacheClass);
}
private function __construct($cacheClass) {
$this->_storage = new $cacheClass();
}
/**
* Set cache
*
* @param string $key
* @param mixed $value
* @param int $expire
*/
public function set($key, $value, $expire = false) {
if (!$expire) {
$expire = $this->_expire;
}
$this->_storage->checkLock($key);
$data = array('time' => time(), 'expire' => $expire, 'valid' => true, 'data' => $value);
$this->_storage->lock($key);
try {
$this->_storage->store($key, $data);
$this->_storage->unlock($key);
} catch (CacheException $e) {
$this->_storage->unlock($key);
throw $e;
}
}
/**
* Read cache
*
* @param string $key
* @return mixed
*/
public function get($key) {
$data = $this->fetch($key);
if ($data && $data['valid'] && !$data['isExpired']) {
return $data['data'];
}
return false;
}
/**
* Read the cache, including expired and invalid ones, to get the complete storage structure
*
* @param string $key
*/
public function fetch($key) {
$this->_storage->checkLock($key);
$data = $this->_storage->fetch($key);
if ($data) {
$data['isExpired'] = (time() - $data['time']) > $data['expire'] ? true : false;
return $data;
}
return false;
}
/**
* Delete cache
*
* @param string $key
*/
public function delete($key) {
$this->_storage->checkLock($key)
->lock($key)
->delete($key)
->unlock($key);
}
public function clear() {
$this->_storage->clear();
}
/**
* Disable cache
*
* @param string $key
*/
public function setInvalidate($key) {
$this->_storage->checkLock($key)
->lock($key);
try {
$data = $this->_storage->fetch($key);
if ($data) {
$data['valid'] = false;
$this->_storage->store($key, $data);
}
$this->_storage->unlock($key);
} catch (CacheException $e) {
$this->_storage->unlock($key);
throw $e;
}
}
/**
* Set cache expiration time (s)
*
* @param int $expire
*/
public function setExpire($expire) {
$this->_expire = (int) $expire;
return $this;
}
}
?>

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