<?php
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|
/**
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+-----------------------------------------------------------------------+
|
| This file is part of the Roundcube Webmail client |
|
| Copyright (C) 2011-2013, The Roundcube Dev Team |
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| Copyright (C) 2011-2013, Kolab Systems AG |
|
| |
|
| Licensed under the GNU General Public License version 3 or |
|
| any later version with exceptions for skins & plugins. |
|
| See the README file for a full license statement. |
|
| |
|
| PURPOSE: |
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| Shared (cross-user) caching engine |
|
+-----------------------------------------------------------------------+
|
| Author: Thomas Bruederli <roundcube@gmail.com> |
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| Author: Aleksander Machniak <alec@alec.pl> |
|
+-----------------------------------------------------------------------+
|
*/
|
|
/**
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* Interface class for accessing Roundcube shared cache
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*
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* @package Framework
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* @subpackage Cache
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* @author Thomas Bruederli <roundcube@gmail.com>
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* @author Aleksander Machniak <alec@alec.pl>
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*/
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class rcube_cache_shared
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{
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/**
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* Instance of database handler
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*
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* @var rcube_db|Memcache|bool
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*/
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private $db;
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private $type;
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private $prefix;
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private $ttl;
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private $packed;
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private $index;
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private $table;
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private $debug;
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private $index_changed = false;
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private $cache = array();
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private $cache_changes = array();
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private $cache_sums = array();
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private $max_packet = -1;
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|
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/**
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* Object constructor.
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*
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* @param string $type Engine type ('db' or 'memcache' or 'apc')
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* @param string $prefix Key name prefix
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* @param string $ttl Expiration time of memcache/apc items
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* @param bool $packed Enables/disabled data serialization.
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* It's possible to disable data serialization if you're sure
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* stored data will be always a safe string
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*/
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function __construct($type, $prefix='', $ttl=0, $packed=true)
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{
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$rcube = rcube::get_instance();
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$type = strtolower($type);
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if ($type == 'memcache') {
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$this->type = 'memcache';
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$this->db = $rcube->get_memcache();
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$this->debug = $rcube->config->get('memcache_debug');
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}
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else if ($type == 'apc') {
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$this->type = 'apc';
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$this->db = function_exists('apc_exists'); // APC 3.1.4 required
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$this->debug = $rcube->config->get('apc_debug');
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}
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else {
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$this->type = 'db';
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$this->db = $rcube->get_dbh();
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$this->table = $this->db->table_name('cache_shared', true);
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}
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// convert ttl string to seconds
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$ttl = get_offset_sec($ttl);
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if ($ttl > 2592000) $ttl = 2592000;
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$this->ttl = $ttl;
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$this->packed = $packed;
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$this->prefix = $prefix;
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}
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/**
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* Returns cached value.
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*
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* @param string $key Cache key name
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*
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* @return mixed Cached value
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*/
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function get($key)
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{
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if (!array_key_exists($key, $this->cache)) {
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return $this->read_record($key);
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}
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return $this->cache[$key];
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}
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/**
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* Sets (add/update) value in cache.
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*
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* @param string $key Cache key name
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* @param mixed $data Cache data
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*/
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function set($key, $data)
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{
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$this->cache[$key] = $data;
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$this->cache_changes[$key] = true;
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}
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/**
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* Returns cached value without storing it in internal memory.
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*
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* @param string $key Cache key name
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*
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* @return mixed Cached value
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*/
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function read($key)
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{
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if (array_key_exists($key, $this->cache)) {
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return $this->cache[$key];
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}
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return $this->read_record($key, true);
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}
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/**
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* Sets (add/update) value in cache and immediately saves
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* it in the backend, no internal memory will be used.
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*
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* @param string $key Cache key name
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* @param mixed $data Cache data
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*
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* @param boolean True on success, False on failure
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*/
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function write($key, $data)
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{
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return $this->write_record($key, $this->serialize($data));
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}
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/**
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* Clears the cache.
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*
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* @param string $key Cache key name or pattern
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* @param boolean $prefix_mode Enable it to clear all keys starting
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* with prefix specified in $key
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*/
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function remove($key=null, $prefix_mode=false)
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{
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// Remove all keys
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if ($key === null) {
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$this->cache = array();
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$this->cache_changes = array();
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$this->cache_sums = array();
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}
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// Remove keys by name prefix
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else if ($prefix_mode) {
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foreach (array_keys($this->cache) as $k) {
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if (strpos($k, $key) === 0) {
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$this->cache[$k] = null;
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$this->cache_changes[$k] = false;
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unset($this->cache_sums[$k]);
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}
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}
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}
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// Remove one key by name
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else {
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$this->cache[$key] = null;
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$this->cache_changes[$key] = false;
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unset($this->cache_sums[$key]);
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}
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// Remove record(s) from the backend
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$this->remove_record($key, $prefix_mode);
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}
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/**
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* Remove cache records older than ttl
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*/
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function expunge()
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{
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if ($this->type == 'db' && $this->db && $this->ttl) {
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$this->db->query(
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"DELETE FROM {$this->table}"
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. " WHERE `cache_key` LIKE ?"
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. " AND `expires` < " . $this->db->now(),
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$this->prefix . '.%');
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}
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}
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/**
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* Remove expired records of all caches
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*/
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static function gc()
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{
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$rcube = rcube::get_instance();
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$db = $rcube->get_dbh();
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$db->query("DELETE FROM " . $db->table_name('cache_shared', true) . " WHERE `expires` < " . $db->now());
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}
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/**
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* Writes the cache back to the DB.
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*/
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function close()
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{
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foreach ($this->cache as $key => $data) {
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// The key has been used
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if ($this->cache_changes[$key]) {
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// Make sure we're not going to write unchanged data
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// by comparing current md5 sum with the sum calculated on DB read
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$data = $this->serialize($data);
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if (!$this->cache_sums[$key] || $this->cache_sums[$key] != md5($data)) {
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$this->write_record($key, $data);
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}
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}
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}
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if ($this->index_changed) {
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$this->write_index();
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}
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// reset internal cache index, thanks to this we can force index reload
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$this->index = null;
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}
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/**
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* Reads cache entry.
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*
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* @param string $key Cache key name
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* @param boolean $nostore Enable to skip in-memory store
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*
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* @return mixed Cached value
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*/
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private function read_record($key, $nostore=false)
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{
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if (!$this->db) {
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return null;
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}
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if ($this->type != 'db') {
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$this->load_index();
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// Consistency check (#1490390)
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if (!in_array($key, $this->index)) {
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// we always check if the key exist in the index
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// to have data in consistent state. Keeping the index consistent
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// is needed for keys delete operation when we delete all keys or by prefix.
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}
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else {
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$ckey = $this->ckey($key);
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if ($this->type == 'memcache') {
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$data = $this->db->get($ckey);
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}
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else if ($this->type == 'apc') {
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$data = apc_fetch($ckey);
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}
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if ($this->debug) {
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$this->debug('get', $ckey, $data);
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}
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}
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if ($data) {
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$md5sum = md5($data);
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$data = $this->unserialize($data);
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if ($nostore) {
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return $data;
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}
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$this->cache_sums[$key] = $md5sum;
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$this->cache[$key] = $data;
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}
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else {
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$this->cache[$key] = null;
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}
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}
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else {
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$sql_result = $this->db->limitquery(
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"SELECT `data`, `cache_key`".
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" FROM {$this->table}" .
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" WHERE `cache_key` = ?".
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// for better performance we allow more records for one key
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// get the newer one
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" ORDER BY `created` DESC",
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0, 1, $this->prefix . '.' . $key);
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if ($sql_arr = $this->db->fetch_assoc($sql_result)) {
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$md5sum = $sql_arr['data'] ? md5($sql_arr['data']) : null;
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if ($sql_arr['data']) {
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$data = $this->unserialize($sql_arr['data']);
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}
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if ($nostore) {
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return $data;
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}
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$this->cache[$key] = $data;
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$this->cache_sums[$key] = $md5sum;
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}
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else {
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$this->cache[$key] = null;
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}
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}
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return $this->cache[$key];
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}
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/**
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* Writes single cache record into DB.
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*
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* @param string $key Cache key name
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* @param mixed $data Serialized cache data
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*
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* @param boolean True on success, False on failure
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*/
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private function write_record($key, $data)
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{
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if (!$this->db) {
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return false;
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}
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// don't attempt to write too big data sets
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if (strlen($data) > $this->max_packet_size()) {
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trigger_error("rcube_cache: max_packet_size ($this->max_packet) exceeded for key $key. Tried to write " . strlen($data) . " bytes", E_USER_WARNING);
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return false;
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}
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if ($this->type == 'memcache' || $this->type == 'apc') {
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$result = $this->add_record($this->ckey($key), $data);
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// make sure index will be updated
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if ($result) {
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if (!array_key_exists($key, $this->cache_sums)) {
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$this->cache_sums[$key] = true;
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}
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$this->load_index();
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if (!$this->index_changed && !in_array($key, $this->index)) {
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$this->index_changed = true;
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}
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}
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return $result;
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}
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$key_exists = array_key_exists($key, $this->cache_sums);
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$key = $this->prefix . '.' . $key;
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// Remove NULL rows (here we don't need to check if the record exist)
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if ($data == 'N;') {
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$this->db->query("DELETE FROM {$this->table} WHERE `cache_key` = ?", $key);
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return true;
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}
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// update existing cache record
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if ($key_exists) {
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$result = $this->db->query(
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"UPDATE {$this->table}" .
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" SET `created` = " . $this->db->now() .
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", `expires` = " . ($this->ttl ? $this->db->now($this->ttl) : 'NULL') .
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", `data` = ?".
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" WHERE `cache_key` = ?",
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$data, $key);
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}
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// add new cache record
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else {
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// for better performance we allow more records for one key
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// so, no need to check if record exist (see rcube_cache::read_record())
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$result = $this->db->query(
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"INSERT INTO {$this->table}".
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" (`created`, `expires`, `cache_key`, `data`)".
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" VALUES (".$this->db->now().", " . ($this->ttl ? $this->db->now($this->ttl) : 'NULL') . ", ?, ?)",
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$key, $data);
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}
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return $this->db->affected_rows($result);
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}
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/**
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* Deletes the cache record(s).
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*
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* @param string $key Cache key name or pattern
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* @param boolean $prefix_mode Enable it to clear all keys starting
|
* with prefix specified in $key
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*/
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private function remove_record($key=null, $prefix_mode=false)
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{
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if (!$this->db) {
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return;
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}
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if ($this->type != 'db') {
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$this->load_index();
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// Remove all keys
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if ($key === null) {
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foreach ($this->index as $key) {
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$this->delete_record($this->ckey($key));
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}
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$this->index = array();
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}
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// Remove keys by name prefix
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else if ($prefix_mode) {
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foreach ($this->index as $idx => $k) {
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if (strpos($k, $key) === 0) {
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$this->delete_record($this->ckey($k));
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unset($this->index[$idx]);
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}
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}
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}
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// Remove one key by name
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else {
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$this->delete_record($this->ckey($key));
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if (($idx = array_search($key, $this->index)) !== false) {
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unset($this->index[$idx]);
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}
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}
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$this->index_changed = true;
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return;
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}
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// Remove all keys (in specified cache)
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if ($key === null) {
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$where = " WHERE `cache_key` LIKE " . $this->db->quote($this->prefix.'.%');
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}
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// Remove keys by name prefix
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else if ($prefix_mode) {
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$where = " WHERE `cache_key` LIKE " . $this->db->quote($this->prefix.'.'.$key.'%');
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}
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// Remove one key by name
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else {
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$where = " WHERE `cache_key` = " . $this->db->quote($this->prefix.'.'.$key);
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}
|
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$this->db->query("DELETE FROM " . $this->table . $where);
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}
|
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/**
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* Adds entry into memcache/apc DB.
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*
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* @param string $key Cache internal key name
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* @param mixed $data Serialized cache data
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*
|
* @param boolean True on success, False on failure
|
*/
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private function add_record($key, $data)
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{
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if ($this->type == 'memcache') {
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$result = $this->db->replace($key, $data, MEMCACHE_COMPRESSED, $this->ttl);
|
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if (!$result) {
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$result = $this->db->set($key, $data, MEMCACHE_COMPRESSED, $this->ttl);
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}
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}
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else if ($this->type == 'apc') {
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if (apc_exists($key)) {
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apc_delete($key);
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}
|
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$result = apc_store($key, $data, $this->ttl);
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}
|
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if ($this->debug) {
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$this->debug('set', $key, $data, $result);
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}
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return $result;
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}
|
|
/**
|
* Deletes entry from memcache/apc DB.
|
*
|
* @param string $key Cache internal key name
|
*
|
* @param boolean True on success, False on failure
|
*/
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private function delete_record($key)
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{
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if ($this->type == 'memcache') {
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// #1488592: use 2nd argument
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$result = $this->db->delete($key, 0);
|
}
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else {
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$result = apc_delete($key);
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}
|
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if ($this->debug) {
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$this->debug('delete', $key, null, $result);
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}
|
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return $result;
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}
|
|
/**
|
* Writes the index entry into memcache/apc DB.
|
*/
|
private function write_index()
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{
|
if (!$this->db || $this->type == 'db') {
|
return;
|
}
|
|
$this->load_index();
|
|
// Make sure index contains new keys
|
foreach ($this->cache as $key => $value) {
|
if ($value !== null && !in_array($key, $this->index)) {
|
$this->index[] = $key;
|
}
|
}
|
|
// new keys added using self::write()
|
foreach ($this->cache_sums as $key => $value) {
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if ($value === true && !in_array($key, $this->index)) {
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$this->index[] = $key;
|
}
|
}
|
|
$data = serialize($this->index);
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$this->add_record($this->ikey(), $data);
|
}
|
|
/**
|
* Gets the index entry from memcache/apc DB.
|
*/
|
private function load_index()
|
{
|
if (!$this->db || $this->type == 'db') {
|
return;
|
}
|
|
if ($this->index !== null) {
|
return;
|
}
|
|
$index_key = $this->ikey();
|
|
if ($this->type == 'memcache') {
|
$data = $this->db->get($index_key);
|
}
|
else if ($this->type == 'apc') {
|
$data = apc_fetch($index_key);
|
}
|
|
if ($this->debug) {
|
$this->debug('get', $index_key, $data);
|
}
|
|
$this->index = $data ? unserialize($data) : array();
|
}
|
|
/**
|
* Creates cache key name (for memcache and apc)
|
*
|
* @param string $key Cache key name
|
*
|
* @return string Cache key
|
*/
|
private function ckey($key)
|
{
|
return $this->prefix . ':' . $key;
|
}
|
|
/**
|
* Creates index cache key name (for memcache and apc)
|
*
|
* @return string Cache key
|
*/
|
private function ikey()
|
{
|
// This way each cache will have its own index
|
return $this->prefix . 'INDEX';
|
}
|
|
/**
|
* Serializes data for storing
|
*/
|
private function serialize($data)
|
{
|
if ($this->type == 'db') {
|
return $this->db->encode($data, $this->packed);
|
}
|
|
return $this->packed ? serialize($data) : $data;
|
}
|
|
/**
|
* Unserializes serialized data
|
*/
|
private function unserialize($data)
|
{
|
if ($this->type == 'db') {
|
return $this->db->decode($data, $this->packed);
|
}
|
|
return $this->packed ? @unserialize($data) : $data;
|
}
|
|
/**
|
* Determine the maximum size for cache data to be written
|
*/
|
private function max_packet_size()
|
{
|
if ($this->max_packet < 0) {
|
$this->max_packet = 2097152; // default/max is 2 MB
|
|
if ($this->type == 'db') {
|
if ($value = $this->db->get_variable('max_allowed_packet', $this->max_packet)) {
|
$this->max_packet = $value;
|
}
|
$this->max_packet -= 2000;
|
}
|
else if ($this->type == 'memcache') {
|
$stats = $this->db->getStats();
|
$remaining = $stats['limit_maxbytes'] - $stats['bytes'];
|
$this->max_packet = min($remaining / 5, $this->max_packet);
|
}
|
else if ($this->type == 'apc' && function_exists('apc_sma_info')) {
|
$stats = apc_sma_info();
|
$this->max_packet = min($stats['avail_mem'] / 5, $this->max_packet);
|
}
|
}
|
|
return $this->max_packet;
|
}
|
|
/**
|
* Write memcache/apc debug info to the log
|
*/
|
private function debug($type, $key, $data = null, $result = null)
|
{
|
$line = strtoupper($type) . ' ' . $key;
|
|
if ($data !== null) {
|
$line .= ' ' . ($this->packed ? $data : serialize($data));
|
}
|
|
rcube::debug($this->type, $line, $result);
|
}
|
}
|
