MemcachedBackend.php

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<?php
 
/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */
 
namespace ‪TYPO3\CMS\Core\Cache\Backend;
 
use ‪TYPO3\CMS\Core\Cache\Exception;
use ‪TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
use ‪TYPO3\CMS\Core\Core\Environment;
 
class ‪MemcachedBackend extends ‪AbstractBackend implements ‪TaggableBackendInterface, ‪TransientBackendInterface
{
    const ‪MAX_BUCKET_SIZE = 1048534;
 
    protected ‪$memcache;
 
    protected ‪$usedPeclModule = '';
 
    protected ‪$servers = [];
 
    protected ‪$flags;
 
    protected ‪$identifierPrefix;
 
    public function ‪__construct(‪$context, array $options = [])
    {
        if (!extension_loaded('memcache') && !extension_loaded('memcached')) {
            throw new ‪Exception('The PHP extension "memcache" or "memcached" must be installed and loaded in order to use the Memcached backend.', 1213987706);
        }
 
        parent::__construct(‪$context, $options);
 
        if ($this->usedPeclModule === '') {
            if (extension_loaded('memcache')) {
                $this->usedPeclModule = 'memcache';
            } elseif (extension_loaded('memcached')) {
                $this->usedPeclModule = 'memcached';
            }
        }
    }
 
    protected function ‪setServers(array ‪$servers)
    {
        $this->servers = ‪$servers;
    }
 
    protected function ‪setCompression($useCompression)
    {
        $compressionFlag = $this->usedPeclModule === 'memcache' ? MEMCACHE_COMPRESSED : \Memcached::OPT_COMPRESSION;
        if ($useCompression === true) {
            $this->flags ^= $compressionFlag;
        } else {
            $this->flags &= ~$compressionFlag;
        }
    }
 
    protected function ‪getCompression()
    {
        return $this->flags !== 0;
    }
 
    public function ‪initializeObject()
    {
        if (empty($this->servers)) {
            throw new Exception('No servers were given to Memcache', 1213115903);
        }
        $memcachedPlugin = '\\' . ucfirst($this->usedPeclModule);
        $this->memcache = new $memcachedPlugin();
        $defaultPort = $this->usedPeclModule === 'memcache' ? ini_get('memcache.default_port') : 11211;
        foreach ($this->servers as $server) {
            if (strpos($server, 'unix://') === 0) {
                $host = $server;
                $port = 0;
            } else {
                if (strpos($server, 'tcp://') === 0) {
                    $server = substr($server, 6);
                }
                if (strpos($server, ':') !== false) {
                    [$host, $port] = explode(':', $server, 2);
                } else {
                    $host = $server;
                    $port = $defaultPort;
                }
            }
            $this->memcache->addserver($host, $port);
        }
        if ($this->usedPeclModule === 'memcached') {
            $this->memcache->setOption(\Memcached::OPT_COMPRESSION, $this->‪getCompression());
        }
    }
 
    public function ‪setPeclModule($peclModule)
    {
        if ($peclModule !== 'memcache' && $peclModule !== 'memcached') {
            throw new Exception('PECL module must be either "memcache" or "memcached".', 1442239768);
        }
 
        $this->usedPeclModule = $peclModule;
    }
 
    public function ‪setCache(FrontendInterface ‪$cache)
    {
        parent::setCache(‪$cache);
        $identifierHash = substr(md5(‪Environment::getProjectPath() . $this->context . $this->cacheIdentifier), 0, 12);
        $this->identifierPrefix = 'TYPO3_' . $identifierHash . '_';
    }
 
    public function set($entryIdentifier, $data, array $tags = [], $lifetime = null)
    {
        if (strlen($this->identifierPrefix . $entryIdentifier) > 250) {
            throw new \InvalidArgumentException('Could not set value. Key more than 250 characters (' . $this->identifierPrefix . $entryIdentifier . ').', 1232969508);
        }
        if (!$this->cache instanceof FrontendInterface) {
            throw new Exception('No cache frontend has been set yet via setCache().', 1207149215);
        }
        $tags[] = '%MEMCACHEBE%' . ‪$this->cacheIdentifier;
        $expiration = $lifetime ?? ‪$this->defaultLifetime;
 
        // Memcached considers values over 2592000 sec (30 days) as UNIX timestamp
        // thus $expiration should be converted from lifetime to UNIX timestamp
        if ($expiration > 2592000) {
            $expiration += ‪$GLOBALS['EXEC_TIME'];
        }
        try {
            if (is_string($data) && strlen($data) > self::MAX_BUCKET_SIZE) {
                $data = str_split($data, 1024 * 1000);
                $success = true;
                $chunkNumber = 1;
                foreach ($data as $chunk) {
                    $success = $success && $this->‪setInternal($entryIdentifier . '_chunk_' . $chunkNumber, $chunk, $expiration);
                    $chunkNumber++;
                }
                $success = $success && $this->‪setInternal($entryIdentifier, 'TYPO3*chunked:' . $chunkNumber, $expiration);
            } else {
                $success = $this->‪setInternal($entryIdentifier, $data, $expiration);
            }
            if ($success === true) {
                $this->‪removeIdentifierFromAllTags($entryIdentifier);
                $this->‪addIdentifierToTags($entryIdentifier, $tags);
            } else {
                throw new Exception('Could not set data to memcache server.', 1275830266);
            }
        } catch (\Exception $exception) {
            $this->logger->alert('Memcache: could not set value.', ['exception' => $exception]);
        }
    }
 
    protected function ‪setInternal($entryIdentifier, $data, $expiration)
    {
        if ($this->usedPeclModule === 'memcache') {
            return $this->memcache->set($this->identifierPrefix . $entryIdentifier, $data, $this->flags, $expiration);
        }
        return $this->memcache->set($this->identifierPrefix . $entryIdentifier, $data, $expiration);
    }
 
    public function get($entryIdentifier)
    {
        $value = $this->memcache->get($this->identifierPrefix . $entryIdentifier);
        if (is_string($value) && strpos($value, 'TYPO3*chunked:') === 0) {
            [, $chunkCount] = explode(':', $value);
            $value = '';
            for ($chunkNumber = 1; $chunkNumber < $chunkCount; $chunkNumber++) {
                $value .= $this->memcache->get($this->identifierPrefix . $entryIdentifier . '_chunk_' . $chunkNumber);
            }
        }
        return $value;
    }
 
    public function ‪has($entryIdentifier)
    {
        if ($this->usedPeclModule === 'memcache') {
            return $this->memcache->get($this->identifierPrefix . $entryIdentifier) !== false;
        }
 
        // pecl-memcached supports storing literal FALSE
        $this->memcache->get($this->identifierPrefix . $entryIdentifier);
        return $this->memcache->getResultCode() !== \Memcached::RES_NOTFOUND;
    }
 
    public function remove($entryIdentifier)
    {
        $this->‪removeIdentifierFromAllTags($entryIdentifier);
        return $this->memcache->delete($this->identifierPrefix . $entryIdentifier, 0);
    }
 
    public function ‪findIdentifiersByTag($tag)
    {
        $identifiers = $this->memcache->get($this->identifierPrefix . 'tag_' . $tag);
        if ($identifiers !== false) {
            return (array)$identifiers;
        }
        return [];
    }
 
    public function ‪flush()
    {
        if (!$this->cache instanceof FrontendInterface) {
            throw new Exception('No cache frontend has been set via setCache() yet.', 1204111376);
        }
        $this->‪flushByTag('%MEMCACHEBE%' . $this->cacheIdentifier);
    }
 
    public function ‪flushByTag($tag)
    {
        $identifiers = $this->‪findIdentifiersByTag($tag);
        foreach ($identifiers as $identifier) {
            $this->remove($identifier);
        }
    }
 
    protected function ‪addIdentifierToTags($entryIdentifier, array $tags)
    {
        // Get identifier-to-tag index to look for updates
        $existingTags = $this->‪findTagsByIdentifier($entryIdentifier);
        $existingTagsUpdated = false;
 
        foreach ($tags as $tag) {
            // Update tag-to-identifier index
            $identifiers = $this->‪findIdentifiersByTag($tag);
            if (!in_array($entryIdentifier, $identifiers, true)) {
                $identifiers[] = $entryIdentifier;
                $this->memcache->set($this->identifierPrefix . 'tag_' . $tag, $identifiers);
            }
            // Test if identifier-to-tag index needs update
            if (!in_array($tag, $existingTags, true)) {
                $existingTags[] = $tag;
                $existingTagsUpdated = true;
            }
        }
 
        // Update identifier-to-tag index if needed
        if ($existingTagsUpdated) {
            $this->memcache->set($this->identifierPrefix . 'ident_' . $entryIdentifier, $existingTags);
        }
    }
 
    protected function ‪removeIdentifierFromAllTags($entryIdentifier)
    {
        // Get tags for this identifier
        $tags = $this->‪findTagsByIdentifier($entryIdentifier);
        // De-associate tags with this identifier
        foreach ($tags as $tag) {
            $identifiers = $this->‪findIdentifiersByTag($tag);
            // Formally array_search() below should never return FALSE due to
            // the behavior of findTagsByIdentifier(). But if reverse index is
            // corrupted, we still can get 'FALSE' from array_search(). This is
            // not a problem because we are removing this identifier from
            // anywhere.
            if (($key = array_search($entryIdentifier, $identifiers)) !== false) {
                unset($identifiers[$key]);
                if (!empty($identifiers)) {
                    $this->memcache->set($this->identifierPrefix . 'tag_' . $tag, $identifiers);
                } else {
                    $this->memcache->delete($this->identifierPrefix . 'tag_' . $tag, 0);
                }
            }
        }
        // Clear reverse tag index for this identifier
        $this->memcache->delete($this->identifierPrefix . 'ident_' . $entryIdentifier, 0);
    }
 
    protected function ‪findTagsByIdentifier($identifier)
    {
        $tags = $this->memcache->get($this->identifierPrefix . 'ident_' . $identifier);
        return $tags === false ? [] : (array)$tags;
    }
 
    public function ‪collectGarbage()
    {
    }
}