includes/BagOStuff.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 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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  */
  37 class BagOStuff {
  38         var $debugmode;
  39
  40         function BagOStuff() {
  41                 $this->set_debug( false );
  42         }
  43
  44         function set_debug($bool) {
  45                 $this->debugmode = $bool;
  46         }
  47
  48         /* *** THE GUTS OF THE OPERATION *** */
  49         /* Override these with functional things in subclasses */
  50
  51         function get($key) {
  52                 /* stub */
  53                 return false;
  54         }
  55
  56         function set($key, $value, $exptime=0) {
  57                 /* stub */
  58                 return false;
  59         }
  60
  61         function delete($key, $time=0) {
  62                 /* stub */
  63                 return false;
  64         }
  65
  66         function lock($key, $timeout = 0) {
  67                 /* stub */
  68                 return true;
  69         }
  70
  71         function unlock($key) {
  72                 /* stub */
  73                 return true;
  74         }
  75
  76         /* *** Emulated functions *** */
  77         /* Better performance can likely be got with custom written versions */
  78         function get_multi($keys) {
  79                 $out = array();
  80                 foreach($keys as $key)
  81                         $out[$key] = $this->get($key);
  82                 return $out;
  83         }
  84
  85         function set_multi($hash, $exptime=0) {
  86                 foreach($hash as $key => $value)
  87                         $this->set($key, $value, $exptime);
  88         }
  89
  90         function add($key, $value, $exptime=0) {
  91                 if( $this->get($key) == false ) {
  92                         $this->set($key, $value, $exptime);
  93                         return true;
  94                 }
  95         }
  96
  97         function add_multi($hash, $exptime=0) {
  98                 foreach($hash as $key => $value)
  99                         $this->add($key, $value, $exptime);
 100         }
 101
 102         function delete_multi($keys, $time=0) {
 103                 foreach($keys as $key)
 104                         $this->delete($key, $time);
 105         }
 106
 107         function replace($key, $value, $exptime=0) {
 108                 if( $this->get($key) !== false )
 109                         $this->set($key, $value, $exptime);
 110         }
 111
 112         function incr($key, $value=1) {
 113                 if ( !$this->lock($key) ) {
 114                         return false;
 115                 }
 116                 $value = intval($value);
 117                 if($value < 0) $value = 0;
 118
 119                 $n = false;
 120                 if( ($n = $this->get($key)) !== false ) {
 121                         $n += $value;
 122                         $this->set($key, $n); // exptime?
 123                 }
 124                 $this->unlock($key);
 125                 return $n;
 126         }
 127
 128         function decr($key, $value=1) {
 129                 if ( !$this->lock($key) ) {
 130                         return false;
 131                 }
 132                 $value = intval($value);
 133                 if($value < 0) $value = 0;
 134
 135                 $m = false;
 136                 if( ($n = $this->get($key)) !== false ) {
 137                         $m = $n - $value;
 138                         if($m < 0) $m = 0;
 139                         $this->set($key, $m); // exptime?
 140                 }
 141                 $this->unlock($key);
 142                 return $m;
 143         }
 144
 145         function _debug($text) {
 146                 if($this->debugmode)
 147                         wfDebug("BagOStuff debug: $text\n");
 148         }
 149
 150         /**
 151          * Convert an optionally relative time to an absolute time
 152          */
 153         static function convertExpiry( $exptime ) {
 154                 if(($exptime != 0) && ($exptime < 3600*24*30)) {
 155                         return time() + $exptime;
 156                 } else {
 157                         return $exptime;
 158                 }
 159         }
 160 }
 161
 162
 163 /**
 164  * Functional versions!
 165  * @todo document
 166  * @package MediaWiki
 167  */
 168 class HashBagOStuff extends BagOStuff {
 169         /*
 170            This is a test of the interface, mainly. It stores
 171            things in an associative array, which is not going to
 172            persist between program runs.
 173         */
 174         var $bag;
 175
 176         function HashBagOStuff() {
 177                 $this->bag = array();
 178         }
 179
 180         function _expire($key) {
 181                 $et = $this->bag[$key][1];
 182                 if(($et == 0) || ($et > time()))
 183                         return false;
 184                 $this->delete($key);
 185                 return true;
 186         }
 187
 188         function get($key) {
 189                 if(!$this->bag[$key])
 190                         return false;
 191                 if($this->_expire($key))
 192                         return false;
 193                 return $this->bag[$key][0];
 194         }
 195
 196         function set($key,$value,$exptime=0) {
 197                 $this->bag[$key] = array( $value, BagOStuff::convertExpiry( $exptime ) );
 198         }
 199
 200         function delete($key,$time=0) {
 201                 if(!$this->bag[$key])
 202                         return false;
 203                 unset($this->bag[$key]);
 204                 return true;
 205         }
 206 }
 207
 208 /*
 209 CREATE TABLE objectcache (
 210   keyname char(255) binary not null default '',
 211   value mediumblob,
 212   exptime datetime,
 213   unique key (keyname),
 214   key (exptime)
 215 );
 216 */
 217
 218 /**
 219  * @todo document
 220  * @abstract
 221  * @package MediaWiki
 222  */
 223 abstract class SqlBagOStuff extends BagOStuff {
 224         var $table;
 225         var $lastexpireall = 0;
 226
 227         function SqlBagOStuff($tablename = 'objectcache') {
 228                 $this->table = $tablename;
 229         }
 230
 231         function get($key) {
 232                 /* expire old entries if any */
 233                 $this->garbageCollect();
 234
 235                 $res = $this->_query(
 236                         "SELECT value,exptime FROM $0 WHERE keyname='$1'", $key);
 237                 if(!$res) {
 238                         $this->_debug("get: ** error: " . $this->_dberror($res) . " **");
 239                         return false;
 240                 }
 241                 if($row=$this->_fetchobject($res)) {
 242                         $this->_debug("get: retrieved data; exp time is " . $row->exptime);
 243                         return $this->_unserialize($this->_blobdecode($row->value));
 244                 } else {
 245                         $this->_debug('get: no matching rows');
 246                 }
 247                 return false;
 248         }
 249
 250         function set($key,$value,$exptime=0) {
 251                 $exptime = intval($exptime);
 252                 if($exptime < 0) $exptime = 0;
 253                 if($exptime == 0) {
 254                         $exp = $this->_maxdatetime();
 255                 } else {
 256                         if($exptime < 3600*24*30)
 257                                 $exptime += time();
 258                         $exp = $this->_fromunixtime($exptime);
 259                 }
 260                 $this->delete( $key );
 261                 $this->_doinsert($this->getTableName(), array(
 262                                         'keyname' => $key,
 263                                         'value' => $this->_blobencode($this->_serialize($value)),
 264                                         'exptime' => $exp
 265                                 ));
 266                 return true; /* ? */
 267         }
 268
 269         function delete($key,$time=0) {
 270                 $this->_query(
 271                         "DELETE FROM $0 WHERE keyname='$1'", $key );
 272                 return true; /* ? */
 273         }
 274
 275         function getTableName() {
 276                 return $this->table;
 277         }
 278
 279         function _query($sql) {
 280                 $reps = func_get_args();
 281                 $reps[0] = $this->getTableName();
 282                 // ewwww
 283                 for($i=0;$i<count($reps);$i++) {
 284                         $sql = str_replace(
 285                                 '$' . $i,
 286                                 $i > 0 ? $this->_strencode($reps[$i]) : $reps[$i],
 287                                 $sql);
 288                 }
 289                 $res = $this->_doquery($sql);
 290                 if($res == false) {
 291                         $this->_debug('query failed: ' . $this->_dberror($res));
 292                 }
 293                 return $res;
 294         }
 295
 296         function _strencode($str) {
 297                 /* Protect strings in SQL */
 298                 return str_replace( "'", "''", $str );
 299         }
 300         function _blobencode($str) {
 301                 return $str;
 302         }
 303         function _blobdecode($str) {
 304                 return $str;
 305         }
 306
 307         abstract function _doinsert($table, $vals);
 308         abstract function _doquery($sql);
 309
 310         function _freeresult($result) {
 311                 /* stub */
 312                 return false;
 313         }
 314
 315         function _dberror($result) {
 316                 /* stub */
 317                 return 'unknown error';
 318         }
 319
 320         abstract function _maxdatetime();
 321         abstract function _fromunixtime($ts);
 322
 323         function garbageCollect() {
 324                 /* Ignore 99% of requests */
 325                 if ( !mt_rand( 0, 100 ) ) {
 326                         $nowtime = time();
 327                         /* Avoid repeating the delete within a few seconds */
 328                         if ( $nowtime > ($this->lastexpireall + 1) ) {
 329                                 $this->lastexpireall = $nowtime;
 330                                 $this->expireall();
 331                         }
 332                 }
 333         }
 334
 335         function expireall() {
 336                 /* Remove any items that have expired */
 337                 $now = $this->_fromunixtime( time() );
 338                 $this->_query( "DELETE FROM $0 WHERE exptime < '$now'" );
 339         }
 340
 341         function deleteall() {
 342                 /* Clear *all* items from cache table */
 343                 $this->_query( "DELETE FROM $0" );
 344         }
 345
 346         /**
 347          * Serialize an object and, if possible, compress the representation.
 348          * On typical message and page data, this can provide a 3X decrease
 349          * in storage requirements.
 350          *
 351          * @param mixed $data
 352          * @return string
 353          */
 354         function _serialize( &$data ) {
 355                 $serial = serialize( $data );
 356                 if( function_exists( 'gzdeflate' ) ) {
 357                         return gzdeflate( $serial );
 358                 } else {
 359                         return $serial;
 360                 }
 361         }
 362
 363         /**
 364          * Unserialize and, if necessary, decompress an object.
 365          * @param string $serial
 366          * @return mixed
 367          */
 368         function _unserialize( $serial ) {
 369                 if( function_exists( 'gzinflate' ) ) {
 370                         $decomp = @gzinflate( $serial );
 371                         if( false !== $decomp ) {
 372                                 $serial = $decomp;
 373                         }
 374                 }
 375                 $ret = unserialize( $serial );
 376                 return $ret;
 377         }
 378 }
 379
 380 /**
 381  * @todo document
 382  * @package MediaWiki
 383  */
 384 class MediaWikiBagOStuff extends SqlBagOStuff {
 385         var $tableInitialised = false;
 386
 387         function _doquery($sql) {
 388                 $dbw =& wfGetDB( DB_MASTER );
 389                 return $dbw->query($sql, 'MediaWikiBagOStuff::_doquery');
 390         }
 391         function _doinsert($t, $v) {
 392                 $dbw =& wfGetDB( DB_MASTER );
 393                 return $dbw->insert($t, $v, 'MediaWikiBagOStuff::_doinsert');
 394         }
 395         function _fetchobject($result) {
 396                 $dbw =& wfGetDB( DB_MASTER );
 397                 return $dbw->fetchObject($result);
 398         }
 399         function _freeresult($result) {
 400                 $dbw =& wfGetDB( DB_MASTER );
 401                 return $dbw->freeResult($result);
 402         }
 403         function _dberror($result) {
 404                 $dbw =& wfGetDB( DB_MASTER );
 405                 return $dbw->lastError();
 406         }
 407         function _maxdatetime() {
 408                 $dbw =& wfGetDB(DB_MASTER);
 409                 return $dbw->timestamp('9999-12-31 12:59:59');
 410         }
 411         function _fromunixtime($ts) {
 412                 $dbw =& wfGetDB(DB_MASTER);
 413                 return $dbw->timestamp($ts);
 414         }
 415         function _strencode($s) {
 416                 $dbw =& wfGetDB( DB_MASTER );
 417                 return $dbw->strencode($s);
 418         }
 419         function _blobencode($s) {
 420                 $dbw =& wfGetDB( DB_MASTER );
 421                 return $dbw->encodeBlob($s);
 422         }
 423         function _blobdecode($s) {
 424                 $dbw =& wfGetDB( DB_MASTER );
 425                 return $dbw->decodeBlob($s);
 426         }
 427         function getTableName() {
 428                 if ( !$this->tableInitialised ) {
 429                         $dbw =& wfGetDB( DB_MASTER );
 430                         /* This is actually a hack, we should be able
 431                            to use Language classes here... or not */
 432                         if (!$dbw)
 433                                 throw new MWException("Could not connect to database");
 434                         $this->table = $dbw->tableName( $this->table );
 435                         $this->tableInitialised = true;
 436                 }
 437                 return $this->table;
 438         }
 439 }
 440
 441 /**
 442  * This is a wrapper for Turck MMCache's shared memory functions.
 443  *
 444  * You can store objects with mmcache_put() and mmcache_get(), but Turck seems
 445  * to use a weird custom serializer that randomly segfaults. So we wrap calls
 446  * with serialize()/unserialize().
 447  *
 448  * The thing I noticed about the Turck serialized data was that unlike ordinary
 449  * serialize(), it contained the names of methods, and judging by the amount of
 450  * binary data, perhaps even the bytecode of the methods themselves. It may be
 451  * that Turck's serializer is faster, so a possible future extension would be
 452  * to use it for arrays but not for objects.
 453  *
 454  * @package MediaWiki
 455  */
 456 class TurckBagOStuff extends BagOStuff {
 457         function get($key) {
 458                 $val = mmcache_get( $key );
 459                 if ( is_string( $val ) ) {
 460                         $val = unserialize( $val );
 461                 }
 462                 return $val;
 463         }
 464
 465         function set($key, $value, $exptime=0) {
 466                 mmcache_put( $key, serialize( $value ), $exptime );
 467                 return true;
 468         }
 469
 470         function delete($key, $time=0) {
 471                 mmcache_rm( $key );
 472                 return true;
 473         }
 474
 475         function lock($key, $waitTimeout = 0 ) {
 476                 mmcache_lock( $key );
 477                 return true;
 478         }
 479
 480         function unlock($key) {
 481                 mmcache_unlock( $key );
 482                 return true;
 483         }
 484 }
 485
 486 /**
 487  * This is a wrapper for APC's shared memory functions
 488  *
 489  * @package MediaWiki
 490  */
 491
 492 class APCBagOStuff extends BagOStuff {
 493         function get($key) {
 494                 $val = apc_fetch($key);
 495                 return $val;
 496         }
 497
 498         function set($key, $value, $exptime=0) {
 499                 apc_store($key, $value, $exptime);
 500                 return true;
 501         }
 502
 503         function delete($key, $time=0) {
 504                 apc_delete($key);
 505                 return true;
 506         }
 507 }
 508
 509
 510 /**
 511  * This is a wrapper for eAccelerator's shared memory functions.
 512  *
 513  * This is basically identical to the Turck MMCache version,
 514  * mostly because eAccelerator is based on Turck MMCache.
 515  *
 516  * @package MediaWiki
 517  */
 518 class eAccelBagOStuff extends BagOStuff {
 519         function get($key) {
 520                 $val = eaccelerator_get( $key );
 521                 if ( is_string( $val ) ) {
 522                         $val = unserialize( $val );
 523                 }
 524                 return $val;
 525         }
 526
 527         function set($key, $value, $exptime=0) {
 528                 eaccelerator_put( $key, serialize( $value ), $exptime );
 529                 return true;
 530         }
 531
 532         function delete($key, $time=0) {
 533                 eaccelerator_rm( $key );
 534                 return true;
 535         }
 536
 537         function lock($key, $waitTimeout = 0 ) {
 538                 eaccelerator_lock( $key );
 539                 return true;
 540         }
 541
 542         function unlock($key) {
 543                 eaccelerator_unlock( $key );
 544                 return true;
 545         }
 546 }
 547
 548 class DBABagOStuff extends BagOStuff {
 549         var $mHandler, $mFile, $mReader, $mWriter, $mDisabled;
 550
 551         function __construct( $handler = 'db3', $dir = false ) {
 552                 if ( $dir === false ) {
 553                         global $wgTmpDirectory;
 554                         $dir = $wgTmpDirectory;
 555                 }
 556                 $this->mFile = "$dir/mw-cache-" . wfWikiID();
 557                 $this->mFile .= '.db';
 558                 $this->mHandler = $handler;
 559         }
 560
 561         /**
 562          * Encode value and expiry for storage
 563          */
 564         function encode( $value, $expiry ) {
 565                 # Convert to absolute time
 566                 $expiry = BagOStuff::convertExpiry( $expiry );
 567                 return sprintf( '%010u', intval( $expiry ) ) . ' ' . serialize( $value );
 568         }
 569
 570         /**
 571          * @return list containing value first and expiry second
 572          */
 573         function decode( $blob ) {
 574                 if ( !is_string( $blob ) ) {
 575                         return array( null, 0 );
 576                 } else {
 577                         return array(
 578                                 unserialize( substr( $blob, 11 ) ),
 579                                 intval( substr( $blob, 0, 10 ) )
 580                         );
 581                 }
 582         }
 583
 584         function getReader() {
 585                 if ( file_exists( $this->mFile ) ) {
 586                         $handle = dba_open( $this->mFile, 'rl', $this->mHandler );
 587                 } else {
 588                         $handle = $this->getWriter();
 589                 }
 590                 if ( !$handle ) {
 591                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 592                 }
 593                 return $handle;
 594         }
 595
 596         function getWriter() {
 597                 $handle = dba_open( $this->mFile, 'cl', $this->mHandler );
 598                 if ( !$handle ) {
 599                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 600                 }
 601                 return $handle;
 602         }
 603
 604         function get( $key ) {
 605                 wfProfileIn( __METHOD__ );
 606                 wfDebug( __METHOD__."($key)\n" );
 607                 $handle = $this->getReader();
 608                 if ( !$handle ) {
 609                         return null;
 610                 }
 611                 $val = dba_fetch( $key, $handle );
 612                 list( $val, $expiry ) = $this->decode( $val );
 613                 # Must close ASAP because locks are held
 614                 dba_close( $handle );
 615
 616                 if ( !is_null( $val ) && $expiry && $expiry < time() ) {
 617                         # Key is expired, delete it
 618                         $handle = $this->getWriter();
 619                         dba_delete( $key, $handle );
 620                         dba_close( $handle );
 621                         wfDebug( __METHOD__.": $key expired\n" );
 622                         $val = null;
 623                 }
 624                 wfProfileOut( __METHOD__ );
 625                 return $val;
 626         }
 627
 628         function set( $key, $value, $exptime=0 ) {
 629                 wfProfileIn( __METHOD__ );
 630                 wfDebug( __METHOD__."($key)\n" );
 631                 $blob = $this->encode( $value, $exptime );
 632                 $handle = $this->getWriter();
 633                 if ( !$handle ) {
 634                         return false;
 635                 }
 636                 $ret = dba_replace( $key, $blob, $handle );
 637                 dba_close( $handle );
 638                 wfProfileOut( __METHOD__ );
 639                 return $ret;
 640         }
 641
 642         function delete( $key, $time = 0 ) {
 643                 wfProfileIn( __METHOD__ );
 644                 $handle = $this->getWriter();
 645                 if ( !$handle ) {
 646                         return false;
 647                 }
 648                 $ret = dba_delete( $key, $handle );
 649                 dba_close( $handle );
 650                 wfProfileOut( __METHOD__ );
 651                 return $ret;
 652         }
 653
 654         function add( $key, $value, $exptime = 0 ) {
 655                 wfProfileIn( __METHOD__ );
 656                 $blob = $this->encode( $value, $exptime );
 657                 $handle = $this->getWriter();
 658                 if ( !$handle ) {
 659                         return false;
 660                 }
 661                 $ret = dba_insert( $key, $blob, $handle );
 662                 # Insert failed, check to see if it failed due to an expired key
 663                 if ( !$ret ) {
 664                         list( $value, $expiry ) = $this->decode( dba_fetch( $key, $handle ) );
 665                         if ( $expiry < time() ) {
 666                                 # Yes expired, delete and try again
 667                                 dba_delete( $key, $handle );
 668                                 $ret = dba_insert( $key, $blob, $handle );
 669                                 # This time if it failed then it will be handled by the caller like any other race
 670                         }
 671                 }
 672
 673                 dba_close( $handle );
 674                 wfProfileOut( __METHOD__ );
 675                 return $ret;
 676         }
 677 }
 678
 679 ?>