includes/ObjectCache.php

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