251 lines
7.9 KiB
PHP
251 lines
7.9 KiB
PHP
<?php
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/**
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* StatusNet - the distributed open-source microblogging tool
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* Copyright (C) 2009, StatusNet, Inc.
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*
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* Plugin to implement cache interface for memcache
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*
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* PHP version 5
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* @category Cache
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* @package StatusNet
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* @author Evan Prodromou <evan@status.net>
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* @copyright 2009 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
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* @link http://status.net/
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*/
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if (!defined('STATUSNET')) {
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// This check helps protect against security problems;
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// your code file can't be executed directly from the web.
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exit(1);
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}
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/**
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* A plugin to use memcache for the cache interface
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*
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* This used to be encoded as config-variable options in the core code;
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* it's now broken out to a separate plugin. The same interface can be
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* implemented by other plugins.
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*
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* @category Cache
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* @package StatusNet
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* @author Evan Prodromou <evan@status.net>
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* @copyright 2009 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
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* @link http://status.net/
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*/
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class MemcachePlugin extends Plugin
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{
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static $cacheInitialized = false;
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private $_conn = null;
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public $servers = array('127.0.0.1;11211');
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public $compressThreshold = 20480;
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public $compressMinSaving = 0.2;
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public $persistent = null;
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public $defaultExpiry = 86400; // 24h
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/**
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* Initialize the plugin
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*
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* Note that onStartCacheGet() may have been called before this!
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*
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* @return boolean flag value
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*/
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function onInitializePlugin()
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{
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if (self::$cacheInitialized) {
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$this->persistent = true;
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} else {
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// If we're a parent command-line process we need
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// to be able to close out the connection after
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// forking, so disable persistence.
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//
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// We'll turn it back on again the second time
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// through which will either be in a child process,
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// or a single-process script which is switching
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// configurations.
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$this->persistent = (php_sapi_name() == 'cli') ? false : true;
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}
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$this->_ensureConn();
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self::$cacheInitialized = true;
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return true;
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}
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/**
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* Get a value associated with a key
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*
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* The value should have been set previously.
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*
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* @param string &$key in; Lookup key
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* @param mixed &$value out; value associated with key
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*
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* @return boolean hook success
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*/
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function onStartCacheGet(&$key, &$value)
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{
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$this->_ensureConn();
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$value = $this->_conn->get($key);
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Event::handle('EndCacheGet', array($key, &$value));
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return false;
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}
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/**
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* Associate a value with a key
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*
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* @param string &$key in; Key to use for lookups
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* @param mixed &$value in; Value to associate
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* @param integer &$flag in; Flag empty or Cache::COMPRESSED
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* @param integer &$expiry in; Expiry (passed through to Memcache)
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* @param boolean &$success out; Whether the set was successful
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*
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* @return boolean hook success
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*/
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function onStartCacheSet(&$key, &$value, &$flag, &$expiry, &$success)
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{
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$this->_ensureConn();
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if ($expiry === null) {
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$expiry = $this->defaultExpiry;
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}
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$success = $this->_conn->set($key, $value, $this->flag(intval($flag)), $expiry);
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Event::handle('EndCacheSet', array($key, $value, $flag,
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$expiry));
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return false;
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}
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/**
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* Atomically increment an existing numeric key value.
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* Existing expiration time will not be changed.
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*
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* @param string &$key in; Key to use for lookups
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* @param int &$step in; Amount to increment (default 1)
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* @param mixed &$value out; Incremented value, or false if key not set.
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*
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* @return boolean hook success
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*/
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function onStartCacheIncrement(&$key, &$step, &$value)
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{
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$this->_ensureConn();
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$value = $this->_conn->increment($key, $step);
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Event::handle('EndCacheIncrement', array($key, $step, $value));
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return false;
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}
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/**
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* Delete a value associated with a key
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*
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* @param string &$key in; Key to lookup
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* @param boolean &$success out; whether it worked
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*
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* @return boolean hook success
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*/
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function onStartCacheDelete(&$key, &$success)
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{
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$this->_ensureConn();
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$success = $this->_conn->delete($key);
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Event::handle('EndCacheDelete', array($key));
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return false;
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}
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function onStartCacheReconnect(&$success)
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{
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if (empty($this->_conn)) {
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// nothing to do
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return true;
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}
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if ($this->persistent) {
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common_log(LOG_ERR, "Cannot close persistent memcached connection");
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$success = false;
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} else {
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common_log(LOG_INFO, "Closing memcached connection");
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$success = $this->_conn->close();
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$this->_conn = null;
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}
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return false;
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}
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/**
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* Ensure that a connection exists
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*
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* Checks the instance $_conn variable and connects
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* if it is empty.
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*
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* @return void
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*/
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private function _ensureConn()
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{
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if (empty($this->_conn)) {
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$this->_conn = new Memcache();
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if (is_array($this->servers)) {
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$servers = $this->servers;
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} else {
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$servers = array($this->servers);
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}
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foreach ($servers as $server) {
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if (strpos($server, ';') !== false) {
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list($host, $port) = explode(';', $server);
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} else {
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$host = $server;
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$port = 11211;
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}
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$this->_conn->addServer($host, $port, $this->persistent);
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}
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// Compress items stored in the cache if they're over threshold in size
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// (default 2KiB) and the compression would save more than min savings
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// ratio (default 0.2).
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// Allows the cache to store objects larger than 1MB (if they
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// compress to less than 1MB), and improves cache memory efficiency.
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$this->_conn->setCompressThreshold($this->compressThreshold,
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$this->compressMinSaving);
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}
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}
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/**
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* Translate general flags to Memcached-specific flags
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* @param int $flag
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* @return int
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*/
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protected function flag($flag)
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{
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$out = 0;
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if ($flag & Cache::COMPRESSED == Cache::COMPRESSED) {
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$out |= MEMCACHE_COMPRESSED;
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}
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return $out;
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}
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function onPluginVersion(&$versions)
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{
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$versions[] = array('name' => 'Memcache',
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'version' => GNUSOCIAL_VERSION,
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'author' => 'Evan Prodromou, Craig Andrews',
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'homepage' => 'http://status.net/wiki/Plugin:Memcache',
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'rawdescription' =>
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// TRANS: Plugin description.
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_m('Use <a href="http://memcached.org/">Memcached</a> to cache query results.'));
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return true;
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}
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}
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