php/src/common/Cache.php

   1 <?php
   2 /**
   3  * Licensed to the Apache Software Foundation (ASF) under one
   4  * or more contributor license agreements.  See the NOTICE file
   5  * distributed with this work for additional information
   6  * regarding copyright ownership.  The ASF licenses this file
   7  * to you under the Apache License, Version 2.0 (the
   8  * "License"); you may not use this file except in compliance
   9  * with the License.  You may obtain a copy of the License at
  10  *
  11  *     http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing,
  14  * software distributed under the License is distributed on an
  15  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  16  * KIND, either express or implied.  See the License for the
  17  * specific language governing permissions and limitations
  18  * under the License.
  19  */
  20
  21 class CacheException extends Exception {
  22 }
  23
  24 class RequestTime {
  25
  26   public function getRequestTime() {
  27     return $_SERVER['REQUEST_TIME'];
  28   }
  29 }
  30
  31 class Cache {
  32   /**
  33    * @var RequestTime
  34    */
  35   private $time = null;
  36
  37   /**
  38    * @var CacheStorage
  39    */
  40   private $storage = null;
  41
  42   /**
  43    * @return Cache
  44    */
  45   static public function createCache($cacheClass, $name, RequestTime $time = null) {
  46     return new Cache($cacheClass, $name, $time);
  47   }
  48
  49   private function __construct($cacheClass, $name, RequestTime $time = null) {
  50     $this->storage = new $cacheClass($name);
  51     if ($time == null) {
  52       $this->time = new RequestTime();
  53     } else {
  54       $this->time = $time;
  55     }
  56   }
  57
  58   public function get($key) {
  59     if ($this->storage->isLocked($key)) {
  60       $this->storage->waitForLock($key);
  61     }
  62     $data = $this->storage->fetch($key);
  63     if ($data) {
  64       $data = unserialize($data);
  65       if ($data['valid'] && ($this->time->getRequestTime() - $data['time']) < $data['ttl']) {
  66         return $data['data'];
  67       }
  68     }
  69     return false;
  70   }
  71
  72   public function expiredGet($key) {
  73     if ($this->storage->isLocked($key)) {
  74       $this->storage->waitForLock($key);
  75     }
  76     $data = $this->storage->fetch($key);
  77     if ($data) {
  78       $data = unserialize($data);
  79       return array_merge(array('found' => true), $data);
  80     }
  81     return array('found' => false);
  82   }
  83
  84   public function set($key, $value, $ttl = false) {
  85     if (! $ttl) {
  86       $ttl = Config::Get('cache_time');
  87     }
  88     if ($this->storage->isLocked($key)) {
  89       $this->storage->waitForLock($key);
  90     }
  91     $data = serialize(array('time' => $this->time->getRequestTime(), 'ttl' => $ttl, 'valid' => true, 'data' => $value));
  92     $this->storage->lock($key);
  93     try {
  94       $this->storage->store($key, $data);
  95       $this->storage->unlock($key);
  96     } catch (Exception $e) {
  97       $this->storage->unlock($key);
  98       throw $e;
  99     }
 100   }
 101
 102   public function delete($key) {
 103     if ($this->storage->isLocked($key)) {
 104       $this->storage->waitForLock($key);
 105     }
 106     $this->storage->lock($key);
 107     $this->storage->delete($key);
 108     $this->storage->unlock($key);
 109   }
 110
 111   public function invalidate($key) {
 112     if ($this->storage->isLocked($key)) {
 113       $this->storage->waitForLock($key);
 114     }
 115     $this->storage->lock($key);
 116     try {
 117       $data = $this->storage->fetch($key);
 118       if ($data) {
 119         $data = unserialize($data);
 120         $data = serialize(array('time' => $data['time'], 'ttl' => $data['ttl'], 'valid' => false, 'data' => $data['data']));
 121         $this->storage->store($key, $data);
 122       }
 123       $this->storage->unlock($key);
 124     } catch (Exception $e) {
 125       $this->storage->unlock($key);
 126       throw $e;
 127     }
 128   }
 129 }