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rcube_cache.php
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rcube_cache.php
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<?php
/**
+-----------------------------------------------------------------------+
| This file is part of the Roundcube Webmail client |
| |
| Copyright (C) The Roundcube Dev Team |
| Copyright (C) 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: |
| Caching engine |
+-----------------------------------------------------------------------+
| Author: Thomas Bruederli <roundcube@gmail.com> |
| Author: Aleksander Machniak <alec@alec.pl> |
+-----------------------------------------------------------------------+
*/
/**
* Interface class for accessing Roundcube cache
*
* @package Framework
* @subpackage Cache
*/
class rcube_cache
{
protected $type;
protected $userid;
protected $prefix;
protected $ttl;
protected $packed;
protected $index;
protected $index_changed = false;
protected $debug = false;
protected $cache = array();
protected $cache_changes = array();
protected $cache_sums = array();
protected $max_packet = -1;
/**
* Object factory
*
* @param string $type Engine type ('db', 'memcache', 'apc', 'redis')
* @param int $userid User identifier
* @param string $prefix Key name prefix
* @param string $ttl Expiration time of memcache/apc items
* @param bool $packed Enables/disabled data serialization.
* It's possible to disable data serialization if you're sure
* stored data will be always a safe string
*
* @param rcube_cache Cache object
*/
public static function factory($type, $userid, $prefix = '', $ttl = 0, $packed = true)
{
$driver = strtolower($type) ?: 'db';
$class = "rcube_cache_$driver";
if (!$driver || !class_exists($class)) {
rcube::raise_error(array('code' => 600, 'type' => 'db',
'line' => __LINE__, 'file' => __FILE__,
'message' => "Configuration error. Unsupported cache driver: $driver"),
true, true);
}
return new $class($userid, $prefix, $ttl, $packed);
}
/**
* Object constructor.
*
* @param int $userid User identifier
* @param string $prefix Key name prefix
* @param string $ttl Expiration time of memcache/apc items
* @param bool $packed Enables/disabled data serialization.
* It's possible to disable data serialization if you're sure
* stored data will be always a safe string
*/
public function __construct($userid, $prefix = '', $ttl = 0, $packed = true)
{
// convert ttl string to seconds
$ttl = get_offset_sec($ttl);
if ($ttl > 2592000) $ttl = 2592000;
$this->userid = (int) $userid;
$this->ttl = $ttl;
$this->packed = $packed;
$this->prefix = $prefix;
}
/**
* Returns cached value.
*
* @param string $key Cache key name
*
* @return mixed Cached value
*/
public function get($key)
{
if (!array_key_exists($key, $this->cache)) {
return $this->read_record($key);
}
return $this->cache[$key];
}
/**
* Sets (add/update) value in cache.
*
* @param string $key Cache key name
* @param mixed $data Cache data
*/
public function set($key, $data)
{
$this->cache[$key] = $data;
$this->cache_changes[$key] = true;
}
/**
* Returns cached value without storing it in internal memory.
*
* @param string $key Cache key name
*
* @return mixed Cached value
*/
public function read($key)
{
if (array_key_exists($key, $this->cache)) {
return $this->cache[$key];
}
return $this->read_record($key, true);
}
/**
* Sets (add/update) value in cache and immediately saves
* it in the backend, no internal memory will be used.
*
* @param string $key Cache key name
* @param mixed $data Cache data
*
* @param boolean True on success, False on failure
*/
public function write($key, $data)
{
return $this->write_record($key, $this->serialize($data));
}
/**
* Clears the cache.
*
* @param string $key Cache key name or pattern
* @param boolean $prefix_mode Enable it to clear all keys starting
* with prefix specified in $key
*/
public function remove($key = null, $prefix_mode = false)
{
// Remove all keys
if ($key === null) {
$this->cache = array();
$this->cache_changes = array();
$this->cache_sums = array();
}
// Remove keys by name prefix
else if ($prefix_mode) {
foreach (array_keys($this->cache) as $k) {
if (strpos($k, $key) === 0) {
$this->cache[$k] = null;
$this->cache_changes[$k] = false;
unset($this->cache_sums[$k]);
}
}
}
// Remove one key by name
else {
$this->cache[$key] = null;
$this->cache_changes[$key] = false;
unset($this->cache_sums[$key]);
}
// Remove record(s) from the backend
$this->remove_record($key, $prefix_mode);
}
/**
* Remove cache records older than ttl
*/
public function expunge()
{
// to be overwritten by engine class
}
/**
* Remove expired records of all caches
*/
public static function gc()
{
// Only DB cache requires an action to remove expired entries
rcube_cache_db::gc();
}
/**
* Writes the cache back to the DB.
*/
public function close()
{
foreach ($this->cache as $key => $data) {
// The key has been used
if ($this->cache_changes[$key]) {
// Make sure we're not going to write unchanged data
// by comparing current md5 sum with the sum calculated on DB read
$data = $this->serialize($data);
if (!$this->cache_sums[$key] || $this->cache_sums[$key] != md5($data)) {
$this->write_record($key, $data);
}
}
}
if ($this->index_changed) {
$this->write_index();
}
// reset internal cache index, thanks to this we can force index reload
$this->index = null;
$this->index_changed = false;
$this->cache = array();
$this->cache_sums = array();
$this->cache_changes = array();
}
/**
* A helper to build cache key for specified parameters.
*
* @param string $prefix Key prefix (Max. length 64 characters)
* @param array $params Additional parameters
*
* @return string Key name
*/
public static function key_name($prefix, $params = array())
{
$cache_key = $prefix;
if (!empty($params)) {
$func = function($v) {
if (is_array($v)) {
sort($v);
}
return is_string($v) ? $v : serialize($v);
};
$params = array_map($func, $params);
$cache_key .= '.' . md5(implode(':', $params));
}
return $cache_key;
}
/**
* Reads cache entry.
*
* @param string $key Cache key name
* @param boolean $nostore Enable to skip in-memory store
*
* @return mixed Cached value
*/
protected function read_record($key, $nostore = false)
{
$this->load_index();
// Consistency check (#1490390)
if (!in_array($key, $this->index)) {
// we always check if the key exist in the index
// to have data in consistent state. Keeping the index consistent
// is needed for keys delete operation when we delete all keys or by prefix.
}
else {
$ckey = $this->ckey($key);
$data = $this->get_item($ckey);
}
if ($data !== false) {
$md5sum = md5($data);
$data = $this->unserialize($data);
if ($nostore) {
return $data;
}
$this->cache_sums[$key] = $md5sum;
$this->cache[$key] = $data;
}
else {
$this->cache[$key] = null;
}
return $this->cache[$key];
}
/**
* Writes single cache record into DB.
*
* @param string $key Cache key name
* @param mixed $data Serialized cache data
*
* @param boolean True on success, False on failure
*/
protected function write_record($key, $data)
{
// don't attempt to write too big data sets
if (strlen($data) > $this->max_packet_size()) {
trigger_error("rcube_cache: max_packet_size ($this->max_packet) exceeded for key $key. Tried to write " . strlen($data) . " bytes", E_USER_WARNING);
return false;
}
$result = $this->add_item($this->ckey($key), $data);
// make sure index will be updated
if ($result) {
if (!array_key_exists($key, $this->cache_sums)) {
$this->cache_sums[$key] = true;
}
$this->load_index();
if (!$this->index_changed && !in_array($key, $this->index)) {
$this->index_changed = true;
}
}
return $result;
}
/**
* Deletes the cache record(s).
*
* @param string $key Cache key name or pattern
* @param boolean $prefix_mode Enable it to clear all keys starting
* with prefix specified in $key
*/
protected function remove_record($key = null, $prefix_mode = false)
{
$this->load_index();
// Remove all keys
if ($key === null) {
foreach ($this->index as $key) {
$this->delete_item($this->ckey($key));
}
$this->index = array();
}
// Remove keys by name prefix
else if ($prefix_mode) {
foreach ($this->index as $idx => $k) {
if (strpos($k, $key) === 0) {
$this->delete_item($this->ckey($k));
unset($this->index[$idx]);
}
}
}
// Remove one key by name
else {
$this->delete_item($this->ckey($key));
if (($idx = array_search($key, $this->index)) !== false) {
unset($this->index[$idx]);
}
}
$this->index_changed = true;
}
/**
* Fetches cache entry.
*
* @param string $key Cache internal key name
*
* @return mixed Cached value
*/
protected function get_item($key)
{
// to be overwritten by engine class
}
/**
* Adds entry into memcache/apc/redis DB.
*
* @param string $key Cache internal key name
* @param mixed $data Serialized cache data
*
* @param boolean True on success, False on failure
*/
protected function add_item($key, $data)
{
// to be overwritten by engine class
}
/**
* Deletes entry from memcache/apc/redis DB.
*
* @param string $key Cache internal key name
*
* @param boolean True on success, False on failure
*/
protected function delete_item($key)
{
// to be overwritten by engine class
}
/**
* Writes the index entry into memcache/apc/redis DB.
*/
protected function write_index()
{
$this->load_index();
// Make sure index contains new keys
foreach ($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 => $value) {
if ($value === true && !in_array($key, $this->index)) {
$this->index[] = $key;
}
}
$data = serialize(array_values($this->index));
$this->add_item($this->ikey(), $data);
}
/**
* Gets the index entry from memcache/apc/redis DB.
*/
protected function load_index()
{
if ($this->index !== null) {
return;
}
$index_key = $this->ikey();
$data = $this->get_item($index_key);
$this->index = $data ? unserialize($data) : array();
}
/**
* Creates per-user cache key name (for memcache, apc, redis)
*
* @param string $key Cache key name
*
* @return string Cache key
*/
protected function ckey($key)
{
$key = $this->prefix . ':' . $key;
if ($this->userid) {
$key = $this->userid . ':' . $key;
}
return $key;
}
/**
* Creates per-user index cache key name (for memcache, apc, redis)
*
* @return string Cache key
*/
protected function ikey()
{
$key = $this->prefix . 'INDEX';
if ($this->userid) {
$key = $this->userid . ':' . $key;
}
return $key;
}
/**
* Serializes data for storing
*/
protected function serialize($data)
{
return $this->packed ? serialize($data) : $data;
}
/**
* Unserializes serialized data
*/
protected function unserialize($data)
{
return $this->packed ? @unserialize($data) : $data;
}
/**
* Determine the maximum size for cache data to be written
*/
protected function max_packet_size()
{
if ($this->max_packet < 0) {
$config = rcube::get_instance()->config;
$max_packet = $config->get($this->type . '_max_allowed_packet');
$this->max_packet = parse_bytes($max_packet) ?: 2097152; // default/max is 2 MB
}
return $this->max_packet;
}
/**
* Write memcache/apc/redis debug info to the log
*/
protected function debug($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);
}
}

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