3 * StatusNet - the distributed open-source microblogging tool
4 * Copyright (C) 2010, StatusNet, Inc.
6 * Extra level of caching, in memory
10 * This program is free software: you can redistribute it and/or modify
11 * it under the terms of the GNU Affero General Public License as published by
12 * the Free Software Foundation, either version 3 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU Affero General Public License for more details.
20 * You should have received a copy of the GNU Affero General Public License
21 * along with this program. If not, see <http://www.gnu.org/licenses/>.
25 * @author Evan Prodromou <evan@status.net>
26 * @copyright 2010 StatusNet, Inc.
27 * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
28 * @link http://status.net/
31 if (!defined('STATUSNET')) {
32 // This check helps protect against security problems;
33 // your code file can't be executed directly from the web.
38 * Extra level of caching
40 * This plugin adds an extra level of in-process caching to any regular
41 * cache system like APC, XCache, or Memcache.
43 * Note that since most caching plugins return false for StartCache*
44 * methods, you should add this plugin before them, i.e.
46 * addPlugin('InProcessCache');
47 * addPlugin('XCache');
51 * @author Evan Prodromou <evan@status.net>
52 * @copyright 2010 StatusNet, Inc.
53 * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
54 * @link http://status.net/
57 class InProcessCachePlugin extends Plugin
59 private $_items = array();
60 private $_hits = array();
63 * Get an item from the cache
65 * Called before other cache systems are called (iif this
66 * plugin was loaded correctly, see class comment). If we
67 * have the data, return it, and don't hit the other cache
70 * @param string &$key Key to fetch
71 * @param mixed &$value Resulting value or false for miss
73 * @return boolean false if found, else true
76 function onStartCacheGet(&$key, &$value)
78 if (array_key_exists($key, $this->_items)) {
79 $value = $this->_items[$key];
80 if (array_key_exists($key, $this->_hits)) {
83 $this->_hits[$key] = 1;
85 Event::handle('EndCacheGet', array($key, &$value));
92 * Called at the end of a cache get
94 * If we don't already have the data, we cache it. This
95 * keeps us from having to call the external cache if the
96 * key is requested again.
98 * @param string $key Key to fetch
99 * @param mixed &$value Resulting value or false for miss
101 * @return boolean hook value, true
104 function onEndCacheGet($key, &$value)
106 if (!array_key_exists($key, $this->_items) ||
107 $this->_items[$key] != $value) {
108 $this->_items[$key] = $value;
114 * Called at the end of setting a cache element
116 * Always set the cache element; may overwrite existing
119 * @param string $key Key to fetch
120 * @param mixed $value Resulting value or false for miss
121 * @param integer $flag ignored
122 * @param integer $expiry ignored
124 * @return boolean true
127 function onEndCacheSet($key, $value, $flag, $expiry)
129 $this->_items[$key] = $value;
134 * Called at the end of deleting a cache element
136 * If stuff's deleted from the other cache, we
139 * @param string &$key Key to delete
140 * @param boolean &$success Success flag; ignored
142 * @return boolean true
145 function onStartCacheDelete(&$key, &$success)
147 if (array_key_exists($key, $this->_items)) {
148 unset($this->_items[$key]);
156 * @param array &$versions Array of version blocks
158 * @return boolean true
161 function onPluginVersion(&$versions)
163 $url = 'http://status.net/wiki/Plugin:InProcessCache';
165 $versions[] = array('name' => 'InProcessCache',
166 'version' => STATUSNET_VERSION,
167 'author' => 'Evan Prodromou',
170 _m('Additional in-process cache for plugins.'));
175 * Cleanup function; called at end of process
177 * If the inprocess/stats config value is true, we dump
178 * stats to the log file
180 * @return boolean true
185 if (common_config('inprocess', 'stats')) {
186 $this->log(LOG_INFO, "cache size: " .
187 count($this->_items));
189 foreach ($this->_hits as $hitcount) {
192 $this->log(LOG_INFO, $sum . " hits on " .
193 count($this->_hits) . " keys");