Author: chabotc
Date: Sun Nov 23 23:26:55 2008
New Revision: 720126
URL: http://svn.apache.org/viewvc?rev=720126&view=rev
Log:
Added a simple APC cache implementation
Added:
incubator/shindig/trunk/php/src/common/CacheApc.php
Added: incubator/shindig/trunk/php/src/common/CacheApc.php
URL:
http://svn.apache.org/viewvc/incubator/shindig/trunk/php/src/common/CacheApc.php?rev=720126&view=auto
==============================================================================
--- incubator/shindig/trunk/php/src/common/CacheApc.php (added)
+++ incubator/shindig/trunk/php/src/common/CacheApc.php Sun Nov 23 23:26:55 2008
@@ -0,0 +1,92 @@
+<?php
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * This class impliments APC based caching. While this doesn't share
+ * the cache through multiple servers, having the cache local is quite
+ * efficient (and faster then file based caching in a high-io env)
+ */
+class CacheApc extends Cache {
+
+ public function __construct() {
+ if (! function_exists('apc_add')) {
+ throw new CacheException("Apc functions not available");
+ }
+ }
+
+ private function isLocked($key) {
+ if ((@apc_fetch($key . '.lock')) === false) {
+ return false;
+ }
+ return true;
+ }
+
+ private function createLock($key) {
+ // the interesting thing is that this could fail if the lock was created
in the meantime..
+ // but we'll ignore that out of convenience
+ @apc_add($key . '.lock', '', 5);
+ }
+
+ private function removeLock($key) {
+ // suppress all warnings, if some other process removed it that's ok too
+ @apc_delete($key . '.lock');
+ }
+
+ private function waitForLock($key) {
+ // 20 x 250 = 5 seconds
+ $tries = 20;
+ $cnt = 0;
+ do {
+ // 250 ms is a long time to sleep, but it does stop the server from
burning all resources on polling locks..
+ usleep(250);
+ $cnt ++;
+ } while ($cnt <= $tries && $this->isLocked());
+ if ($this->isLocked()) {
+ // 5 seconds passed, assume the owning process died off and remove it
+ $this->removeLock($key);
+ }
+ }
+
+ public function get($key, $expiration = false) {
+ if (! $expiration) {
+ // default to global cache time
+ $expiration = Config::Get('cache_time');
+ }
+ if (($ret = @apc_fetch($key)) === false) {
+ return false;
+ }
+ if (time() - $ret['time'] > $expiration) {
+ $this->delete($key);
+ return false;
+ }
+ return unserialize($ret['data']);
+ }
+
+ public function set($key, $value) {
+ // we store it with the cache_time default expiration so objects will
atleast get cleaned eventually.
+ if (@apc_store($key, array('time' => time(), 'data' => serialize($value)),
Config::Get('cache_time')) == false) {
+ throw new CacheException("Couldn't store data in cache");
+ }
+ }
+
+ public function delete($key) {
+ @apc_delete($this->connection, $key);
+ }
+}
