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