includes/ObjectCache.php

   1 <?php
   2 # $Id$
   3 #
   4 # Copyright (C) 2003-2004 Brion Vibber <brion@pobox.com>
   5 # http://www.mediawiki.org/
   6 #
   7 # This program is free software; you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation; either version 2 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License along
  18 # with this program; if not, write to the Free Software Foundation, Inc.,
  19 # 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20 # http://www.gnu.org/copyleft/gpl.html
  21 /**
  22  *
  23  * @package MediaWiki
  24  */
  25
  26 /**
  27  * Simple generic object store
  28  *
  29  * interface is intended to be more or less compatible with
  30  * the PHP memcached client.
  31  *
  32  * backends for local hash array and SQL table included:
  33  * $bag = new HashBagOStuff();
  34  * $bag = new MysqlBagOStuff($tablename); # connect to db first
  35  *
  36  * @package MediaWiki
  37  * @abstract
  38  */
  39 class BagOStuff {
  40         var $debugmode;
  41
  42         function BagOStuff() {
  43                 $this->set_debug( false );
  44         }
  45
  46         function set_debug($bool) {
  47                 $this->debugmode = $bool;
  48         }
  49
  50         /* *** THE GUTS OF THE OPERATION *** */
  51         /* Override these with functional things in subclasses */
  52
  53         function get($key) {
  54                 /* stub */
  55                 return false;
  56         }
  57
  58         function set($key, $value, $exptime=0) {
  59                 /* stub */
  60                 return false;
  61         }
  62
  63         function delete($key, $time=0) {
  64                 /* stub */
  65                 return false;
  66         }
  67
  68         function lock($key, $timeout = 0) {
  69                 /* stub */
  70                 return true;
  71         }
  72
  73         function unlock($key) {
  74                 /* stub */
  75                 return true;
  76         }
  77
  78         /* *** Emulated functions *** */
  79         /* Better performance can likely be got with custom written versions */
  80         function get_multi($keys) {
  81                 $out = array();
  82                 foreach($keys as $key)
  83                         $out[$key] = $this->get($key);
  84                 return $out;
  85         }
  86
  87         function set_multi($hash, $exptime=0) {
  88                 foreach($hash as $key => $value)
  89                         $this->set($key, $value, $exptime);
  90         }
  91
  92         function add($key, $value, $exptime=0) {
  93                 if( $this->get($key) == false ) {
  94                         $this->set($key, $value, $exptime);
  95                         return true;
  96                 }
  97         }
  98
  99         function add_multi($hash, $exptime=0) {
 100                 foreach($hash as $key => $value)
 101                         $this->add($key, $value, $exptime);
 102         }
 103
 104         function delete_multi($keys, $time=0) {
 105                 foreach($keys as $key)
 106                         $this->delete($key, $time);
 107         }
 108
 109         function replace($key, $value, $exptime=0) {
 110                 if( $this->get($key) !== false )
 111                         $this->set($key, $value, $exptime);
 112         }
 113
 114         function incr($key, $value=1) {
 115                 if ( !$this->lock($key) ) {
 116                         return false;
 117                 }
 118                 $value = intval($value);
 119                 if($value < 0) $value = 0;
 120
 121                 $n = false;
 122                 if( ($n = $this->get($key)) !== false ) {
 123                         $n += $value;
 124                         $this->set($key, $n); // exptime?
 125                 }
 126                 $this->unlock($key);
 127                 return $n;
 128         }
 129
 130         function decr($key, $value=1) {
 131                 if ( !$this->lock($key) ) {
 132                         return false;
 133                 }
 134                 $value = intval($value);
 135                 if($value < 0) $value = 0;
 136
 137                 $m = false;
 138                 if( ($n = $this->get($key)) !== false ) {
 139                         $m = $n - $value;
 140                         if($m < 0) $m = 0;
 141                         $this->set($key, $m); // exptime?
 142                 }
 143                 $this->unlock($key);
 144                 return $m;
 145         }
 146
 147         function _debug($text) {
 148                 if($this->debugmode)
 149                         wfDebug("BagOStuff debug: $text\n");
 150         }
 151 }
 152
 153
 154 /**
 155  * Functional versions!
 156  * @todo document
 157  * @package MediaWiki
 158  */
 159 class HashBagOStuff extends BagOStuff {
 160         /*
 161            This is a test of the interface, mainly. It stores
 162            things in an associative array, which is not going to
 163            persist between program runs.
 164         */
 165         var $bag;
 166
 167         function HashBagOStuff() {
 168                 $this->bag = array();
 169         }
 170
 171         function _expire($key) {
 172                 $et = $this->bag[$key][1];
 173                 if(($et == 0) || ($et > time()))
 174                         return false;
 175                 $this->delete($key);
 176                 return true;
 177         }
 178
 179         function get($key) {
 180                 if(!$this->bag[$key])
 181                         return false;
 182                 if($this->_expire($key))
 183                         return false;
 184                 return $this->bag[$key][0];
 185         }
 186
 187         function set($key,$value,$exptime=0) {
 188                 if(($exptime != 0) && ($exptime < 3600*24*30))
 189                         $exptime = time() + $exptime;
 190                 $this->bag[$key] = array( $value, $exptime );
 191         }
 192
 193         function delete($key,$time=0) {
 194                 if(!$this->bag[$key])
 195                         return false;
 196                 unset($this->bag[$key]);
 197                 return true;
 198         }
 199 }
 200
 201 /*
 202 CREATE TABLE objectcache (
 203   keyname char(255) binary not null default '',
 204   value mediumblob,
 205   exptime datetime,
 206   unique key (keyname),
 207   key (exptime)
 208 );
 209 */
 210
 211 /**
 212  * @todo document
 213  * @abstract
 214  * @package MediaWiki
 215  */
 216 class SqlBagOStuff extends BagOStuff {
 217         var $table;
 218
 219         function SqlBagOStuff($tablename = 'objectcache') {
 220                 $this->table = $tablename;
 221         }
 222
 223         function get($key) {
 224                 /* expire old entries if any */
 225                 $this->expireall();
 226
 227                 $res = $this->_query(
 228                         "SELECT value,exptime FROM $0 WHERE keyname='$1'", $key);
 229                 if(!$res) {
 230                         $this->_debug("get: ** error: " . $this->_dberror($res) . " **");
 231                         return false;
 232                 }
 233                 if($row=$this->_fetchobject($res)) {
 234                         $this->_debug("get: retrieved data; exp time is " . $row->exptime);
 235                         return $this->_unserialize($row->value);
 236                 } else {
 237                         $this->_debug('get: no matching rows');
 238                 }
 239                 return false;
 240         }
 241
 242         function set($key,$value,$exptime=0) {
 243                 $exptime = intval($exptime);
 244                 if($exptime < 0) $exptime = 0;
 245                 if($exptime == 0) {
 246                         $exp = $this->_maxdatetime();
 247                 } else {
 248                         if($exptime < 3600*24*30)
 249                                 $exptime += time();
 250                         $exp = $this->_fromunixtime($exptime);
 251                 }
 252                 $this->delete( $key );
 253                 $this->_query(
 254                         "INSERT INTO $0 (keyname,value,exptime) VALUES('$1','$2','$exp')",
 255                         $key, $this->_serialize($value));
 256                 return true; /* ? */
 257         }
 258
 259         function delete($key,$time=0) {
 260                 $this->_query(
 261                         "DELETE FROM $0 WHERE keyname='$1'", $key );
 262                 return true; /* ? */
 263         }
 264
 265         function getTableName() {
 266                 return $this->table;
 267         }
 268
 269         function _query($sql) {
 270                 $reps = func_get_args();
 271                 $reps[0] = $this->getTableName();
 272                 // ewwww
 273                 for($i=0;$i<count($reps);$i++) {
 274                         $sql = str_replace(
 275                                 '$' . $i,
 276                                 $this->_strencode($reps[$i]),
 277                                 $sql);
 278                 }
 279                 $res = $this->_doquery($sql);
 280                 if($res == false) {
 281                         $this->_debug('query failed: ' . $this->_dberror($res));
 282                 }
 283                 return $res;
 284         }
 285
 286         function _strencode($str) {
 287                 /* Protect strings in SQL */
 288                 return str_replace( "'", "''", $str );
 289         }
 290
 291         function _doquery($sql) {
 292                 die( 'abstract function SqlBagOStuff::_doquery() must be defined' );
 293         }
 294
 295         function _fetchrow($res) {
 296                 die( 'abstract function SqlBagOStuff::_fetchrow() must be defined' );
 297         }
 298
 299         function _freeresult($result) {
 300                 /* stub */
 301                 return false;
 302         }
 303
 304         function _dberror($result) {
 305                 /* stub */
 306                 return 'unknown error';
 307         }
 308
 309         function _maxdatetime() {
 310                 die( 'abstract function SqlBagOStuff::_maxdatetime() must be defined' );
 311         }
 312
 313         function _fromunixtime() {
 314                 die( 'abstract function SqlBagOStuff::_fromunixtime() must be defined' );
 315         }
 316
 317         function expireall() {
 318                 /* Remove any items that have expired */
 319                 $now=$this->_fromunixtime(time());
 320                 $this->_query( "DELETE FROM $0 WHERE exptime<'$now'" );
 321         }
 322
 323         function deleteall() {
 324                 /* Clear *all* items from cache table */
 325                 $this->_query( "DELETE FROM $0" );
 326         }
 327
 328         /**
 329          * Serialize an object and, if possible, compress the representation.
 330          * On typical message and page data, this can provide a 3X decrease
 331          * in storage requirements.
 332          *
 333          * @param mixed $data
 334          * @return string
 335          */
 336         function _serialize( &$data ) {
 337                 $serial = serialize( $data );
 338                 if( function_exists( 'gzdeflate' ) ) {
 339                         return gzdeflate( $serial );
 340                 } else {
 341                         return $serial;
 342                 }
 343         }
 344
 345         /**
 346          * Unserialize and, if necessary, decompress an object.
 347          * @param string $serial
 348          * @return mixed
 349          */
 350         function &_unserialize( $serial ) {
 351                 if( function_exists( 'gzinflate' ) ) {
 352                         $decomp = @gzinflate( $serial );
 353                         if( false !== $decomp ) {
 354                                 $serial = $decomp;
 355                         }
 356                 }
 357                 return unserialize( $serial );
 358         }
 359 }
 360
 361 /**
 362  * @todo document
 363  * @package MediaWiki
 364  */
 365 class MediaWikiBagOStuff extends SqlBagOStuff {
 366         var $tableInitialised = false;
 367
 368         function _doquery($sql) {
 369                 $dbw =& wfGetDB( DB_MASTER );
 370                 return $dbw->query($sql, 'MediaWikiBagOStuff:_doquery');
 371         }
 372         function _fetchobject($result) {
 373                 $dbw =& wfGetDB( DB_MASTER );
 374                 return $dbw->fetchObject($result);
 375         }
 376         function _freeresult($result) {
 377                 $dbw =& wfGetDB( DB_MASTER );
 378                 return $dbw->freeResult($result);
 379         }
 380         function _dberror($result) {
 381                 $dbw =& wfGetDB( DB_MASTER );
 382                 return $dbw->lastError();
 383         }
 384         function _maxdatetime() {
 385                 return '9999-12-31 12:59:59';
 386         }
 387         function _fromunixtime($ts) {
 388                 return gmdate( 'Y-m-d H:i:s', $ts );
 389         }
 390         function _strencode($s) {
 391                 $dbw =& wfGetDB( DB_MASTER );
 392                 return $dbw->strencode($s);
 393         }
 394         function getTableName() {
 395                 if ( !$this->tableInitialised ) {
 396                         $dbw =& wfGetDB( DB_MASTER );
 397                         $this->table = $dbw->tableName( $this->table );
 398                         $this->tableInitialised = true;
 399                 }
 400                 return $this->table;
 401         }
 402 }
 403
 404 /**
 405  * This is a wrapper for Turck MMCache's shared memory functions.
 406  *
 407  * You can store objects with mmcache_put() and mmcache_get(), but Turck seems
 408  * to use a weird custom serializer that randomly segfaults. So we wrap calls
 409  * with serialize()/unserialize().
 410  *
 411  * The thing I noticed about the Turck serialized data was that unlike ordinary
 412  * serialize(), it contained the names of methods, and judging by the amount of
 413  * binary data, perhaps even the bytecode of the methods themselves. It may be
 414  * that Turck's serializer is faster, so a possible future extension would be
 415  * to use it for arrays but not for objects.
 416  *
 417  * @package MediaWiki
 418  */
 419 class TurckBagOStuff extends BagOStuff {
 420         function get($key) {
 421                 $val = mmcache_get( $key );
 422                 if ( is_string( $val ) ) {
 423                         $val = unserialize( $val );
 424                 }
 425                 return $val;
 426         }
 427
 428         function set($key, $value, $exptime=0) {
 429                 mmcache_put( $key, serialize( $value ), $exptime );
 430                 return true;
 431         }
 432
 433         function delete($key, $time=0) {
 434                 mmcache_rm( $key );
 435                 return true;
 436         }
 437
 438         function lock($key, $waitTimeout = 0 ) {
 439                 mmcache_lock( $key );
 440                 return true;
 441         }
 442
 443         function unlock($key) {
 444                 mmcache_unlock( $key );
 445                 return true;
 446         }
 447 }
 448 ?>