115 lines
3.4 KiB
PHP
115 lines
3.4 KiB
PHP
<?php
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/**
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* Base class for memcached clients.
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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 General Public License as published by
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* the Free Software Foundation; either version 2 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 General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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* @ingroup Cache
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*/
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/**
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* Base class for memcached clients.
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*
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* @ingroup Cache
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*/
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abstract class MemcachedBagOStuff extends MediumSpecificBagOStuff {
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public function __construct( array $params ) {
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parent::__construct( $params );
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$this->attrMap[self::ATTR_SYNCWRITES] = self::QOS_SYNCWRITES_BE; // unreliable
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$this->segmentationSize = $params['maxPreferedKeySize'] ?? 917504; // < 1MiB
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}
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/**
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* Construct a cache key.
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*
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* @since 1.27
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* @param string $keyspace
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* @param array $args
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* @return string
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*/
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public function makeKeyInternal( $keyspace, $args ) {
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// Memcached keys have a maximum length of 255 characters. From that,
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// subtract the number of characters we need for the keyspace and for
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// the separator character needed for each argument. To handle some
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// custom prefixes used by thing like WANObjectCache, limit to 205.
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$charsLeft = 205 - strlen( $keyspace ) - count( $args );
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foreach ( $args as &$arg ) {
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$arg = strtr( $arg, ' ', '_' );
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// Make sure %, #, and non-ASCII chars are escaped
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$arg = preg_replace_callback(
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'/[^\x21-\x22\x24\x26-\x39\x3b-\x7e]+/',
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function ( $m ) {
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return rawurlencode( $m[0] );
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},
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$arg
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);
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// 33 = 32 characters for the MD5 + 1 for the '#' prefix.
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if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
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$arg = '#' . md5( $arg );
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}
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$charsLeft -= strlen( $arg );
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}
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if ( $charsLeft < 0 ) {
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return $keyspace . ':BagOStuff-long-key:##' . md5( implode( ':', $args ) );
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}
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return $keyspace . ':' . implode( ':', $args );
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}
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/**
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* Ensure that a key is safe to use (contains no control characters and no
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* characters above the ASCII range.)
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*
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* @param string $key
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* @return string
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* @throws Exception
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*/
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public function validateKeyEncoding( $key ) {
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if ( preg_match( '/[^\x21-\x7e]+/', $key ) ) {
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throw new Exception( "Key contains invalid characters: $key" );
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}
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return $key;
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}
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/**
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* @param int|float $exptime
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* @return int
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*/
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protected function fixExpiry( $exptime ) {
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if ( $exptime < 0 ) {
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// The PECL driver does not seem to like negative relative values
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$expiresAt = $this->getCurrentTime() + $exptime;
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} elseif ( $this->isRelativeExpiration( $exptime ) ) {
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// TTLs higher than 30 days will be detected as absolute TTLs
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// (UNIX timestamps), and will result in the cache entry being
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// discarded immediately because the expiry is in the past.
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// Clamp expires >30d at 30d, unless they're >=1e9 in which
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// case they are likely to really be absolute (1e9 = 2011-09-09)
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$expiresAt = min( $exptime, self::TTL_MONTH );
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} else {
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$expiresAt = $exptime;
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}
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return (int)$expiresAt;
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}
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}
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