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                         if ( $row->exptime != $this->_maxdatetime() &&
 244                           wfTimestamp( TS_UNIX, $row->exptime ) < time() )
 245                         {
 246                                 $this->_debug("get: key has expired, deleting");
 247                                 $this->delete($key);
 248                                 return false;
 249                         }
 250                         return $this->_unserialize($this->_blobdecode($row->value));
 251                 } else {
 252                         $this->_debug('get: no matching rows');
 253                 }
 254                 return false;
 255         }
 256
 257         function set($key,$value,$exptime=0) {
 258                 $exptime = intval($exptime);
 259                 if($exptime < 0) $exptime = 0;
 260                 if($exptime == 0) {
 261                         $exp = $this->_maxdatetime();
 262                 } else {
 263                         if($exptime < 3.16e8) # ~10 years
 264                                 $exptime += time();
 265                         $exp = $this->_fromunixtime($exptime);
 266                 }
 267                 $this->delete( $key );
 268                 $this->_doinsert($this->getTableName(), array(
 269                                         'keyname' => $key,
 270                                         'value' => $this->_blobencode($this->_serialize($value)),
 271                                         'exptime' => $exp
 272                                 ));
 273                 return true; /* ? */
 274         }
 275
 276         function delete($key,$time=0) {
 277                 $this->_query(
 278                         "DELETE FROM $0 WHERE keyname='$1'", $key );
 279                 return true; /* ? */
 280         }
 281
 282         function getTableName() {
 283                 return $this->table;
 284         }
 285
 286         function _query($sql) {
 287                 $reps = func_get_args();
 288                 $reps[0] = $this->getTableName();
 289                 // ewwww
 290                 for($i=0;$i<count($reps);$i++) {
 291                         $sql = str_replace(
 292                                 '$' . $i,
 293                                 $i > 0 ? $this->_strencode($reps[$i]) : $reps[$i],
 294                                 $sql);
 295                 }
 296                 $res = $this->_doquery($sql);
 297                 if($res == false) {
 298                         $this->_debug('query failed: ' . $this->_dberror($res));
 299                 }
 300                 return $res;
 301         }
 302
 303         function _strencode($str) {
 304                 /* Protect strings in SQL */
 305                 return str_replace( "'", "''", $str );
 306         }
 307         function _blobencode($str) {
 308                 return $str;
 309         }
 310         function _blobdecode($str) {
 311                 return $str;
 312         }
 313
 314         abstract function _doinsert($table, $vals);
 315         abstract function _doquery($sql);
 316
 317         function _freeresult($result) {
 318                 /* stub */
 319                 return false;
 320         }
 321
 322         function _dberror($result) {
 323                 /* stub */
 324                 return 'unknown error';
 325         }
 326
 327         abstract function _maxdatetime();
 328         abstract function _fromunixtime($ts);
 329
 330         function garbageCollect() {
 331                 /* Ignore 99% of requests */
 332                 if ( !mt_rand( 0, 100 ) ) {
 333                         $nowtime = time();
 334                         /* Avoid repeating the delete within a few seconds */
 335                         if ( $nowtime > ($this->lastexpireall + 1) ) {
 336                                 $this->lastexpireall = $nowtime;
 337                                 $this->expireall();
 338                         }
 339                 }
 340         }
 341
 342         function expireall() {
 343                 /* Remove any items that have expired */
 344                 $now = $this->_fromunixtime( time() );
 345                 $this->_query( "DELETE FROM $0 WHERE exptime < '$now'" );
 346         }
 347
 348         function deleteall() {
 349                 /* Clear *all* items from cache table */
 350                 $this->_query( "DELETE FROM $0" );
 351         }
 352
 353         /**
 354          * Serialize an object and, if possible, compress the representation.
 355          * On typical message and page data, this can provide a 3X decrease
 356          * in storage requirements.
 357          *
 358          * @param mixed $data
 359          * @return string
 360          */
 361         function _serialize( &$data ) {
 362                 $serial = serialize( $data );
 363                 if( function_exists( 'gzdeflate' ) ) {
 364                         return gzdeflate( $serial );
 365                 } else {
 366                         return $serial;
 367                 }
 368         }
 369
 370         /**
 371          * Unserialize and, if necessary, decompress an object.
 372          * @param string $serial
 373          * @return mixed
 374          */
 375         function _unserialize( $serial ) {
 376                 if( function_exists( 'gzinflate' ) ) {
 377                         $decomp = @gzinflate( $serial );
 378                         if( false !== $decomp ) {
 379                                 $serial = $decomp;
 380                         }
 381                 }
 382                 $ret = unserialize( $serial );
 383                 return $ret;
 384         }
 385 }
 386
 387 /**
 388  * @todo document
 389  * @package MediaWiki
 390  */
 391 class MediaWikiBagOStuff extends SqlBagOStuff {
 392         var $tableInitialised = false;
 393
 394         function _doquery($sql) {
 395                 $dbw =& wfGetDB( DB_MASTER );
 396                 return $dbw->query($sql, 'MediaWikiBagOStuff::_doquery');
 397         }
 398         function _doinsert($t, $v) {
 399                 $dbw =& wfGetDB( DB_MASTER );
 400                 return $dbw->insert($t, $v, 'MediaWikiBagOStuff::_doinsert',
 401                         array( 'IGNORE' ) );
 402         }
 403         function _fetchobject($result) {
 404                 $dbw =& wfGetDB( DB_MASTER );
 405                 return $dbw->fetchObject($result);
 406         }
 407         function _freeresult($result) {
 408                 $dbw =& wfGetDB( DB_MASTER );
 409                 return $dbw->freeResult($result);
 410         }
 411         function _dberror($result) {
 412                 $dbw =& wfGetDB( DB_MASTER );
 413                 return $dbw->lastError();
 414         }
 415         function _maxdatetime() {
 416                 $dbw =& wfGetDB(DB_MASTER);
 417                 if ( time() > 0x7fffffff ) {
 418                         return $this->_fromunixtime( 1<<62 );
 419                 } else {
 420                         return $this->_fromunixtime( 0x7fffffff );
 421                 }
 422         }
 423         function _fromunixtime($ts) {
 424                 $dbw =& wfGetDB(DB_MASTER);
 425                 return $dbw->timestamp($ts);
 426         }
 427         function _strencode($s) {
 428                 $dbw =& wfGetDB( DB_MASTER );
 429                 return $dbw->strencode($s);
 430         }
 431         function _blobencode($s) {
 432                 $dbw =& wfGetDB( DB_MASTER );
 433                 return $dbw->encodeBlob($s);
 434         }
 435         function _blobdecode($s) {
 436                 $dbw =& wfGetDB( DB_MASTER );
 437                 return $dbw->decodeBlob($s);
 438         }
 439         function getTableName() {
 440                 if ( !$this->tableInitialised ) {
 441                         $dbw =& wfGetDB( DB_MASTER );
 442                         /* This is actually a hack, we should be able
 443                            to use Language classes here... or not */
 444                         if (!$dbw)
 445                                 throw new MWException("Could not connect to database");
 446                         $this->table = $dbw->tableName( $this->table );
 447                         $this->tableInitialised = true;
 448                 }
 449                 return $this->table;
 450         }
 451 }
 452
 453 /**
 454  * This is a wrapper for Turck MMCache's shared memory functions.
 455  *
 456  * You can store objects with mmcache_put() and mmcache_get(), but Turck seems
 457  * to use a weird custom serializer that randomly segfaults. So we wrap calls
 458  * with serialize()/unserialize().
 459  *
 460  * The thing I noticed about the Turck serialized data was that unlike ordinary
 461  * serialize(), it contained the names of methods, and judging by the amount of
 462  * binary data, perhaps even the bytecode of the methods themselves. It may be
 463  * that Turck's serializer is faster, so a possible future extension would be
 464  * to use it for arrays but not for objects.
 465  *
 466  * @package MediaWiki
 467  */
 468 class TurckBagOStuff extends BagOStuff {
 469         function get($key) {
 470                 $val = mmcache_get( $key );
 471                 if ( is_string( $val ) ) {
 472                         $val = unserialize( $val );
 473                 }
 474                 return $val;
 475         }
 476
 477         function set($key, $value, $exptime=0) {
 478                 mmcache_put( $key, serialize( $value ), $exptime );
 479                 return true;
 480         }
 481
 482         function delete($key, $time=0) {
 483                 mmcache_rm( $key );
 484                 return true;
 485         }
 486
 487         function lock($key, $waitTimeout = 0 ) {
 488                 mmcache_lock( $key );
 489                 return true;
 490         }
 491
 492         function unlock($key) {
 493                 mmcache_unlock( $key );
 494                 return true;
 495         }
 496 }
 497
 498 /**
 499  * This is a wrapper for APC's shared memory functions
 500  *
 501  * @package MediaWiki
 502  */
 503
 504 class APCBagOStuff extends BagOStuff {
 505         function get($key) {
 506                 $val = apc_fetch($key);
 507                 if ( is_string( $val ) ) {
 508                         $val = unserialize( $val );
 509                 }
 510                 return $val;
 511         }
 512
 513         function set($key, $value, $exptime=0) {
 514                 apc_store($key, serialize($value), $exptime);
 515                 return true;
 516         }
 517
 518         function delete($key, $time=0) {
 519                 apc_delete($key);
 520                 return true;
 521         }
 522 }
 523
 524
 525 /**
 526  * This is a wrapper for eAccelerator's shared memory functions.
 527  *
 528  * This is basically identical to the Turck MMCache version,
 529  * mostly because eAccelerator is based on Turck MMCache.
 530  *
 531  * @package MediaWiki
 532  */
 533 class eAccelBagOStuff extends BagOStuff {
 534         function get($key) {
 535                 $val = eaccelerator_get( $key );
 536                 if ( is_string( $val ) ) {
 537                         $val = unserialize( $val );
 538                 }
 539                 return $val;
 540         }
 541
 542         function set($key, $value, $exptime=0) {
 543                 eaccelerator_put( $key, serialize( $value ), $exptime );
 544                 return true;
 545         }
 546
 547         function delete($key, $time=0) {
 548                 eaccelerator_rm( $key );
 549                 return true;
 550         }
 551
 552         function lock($key, $waitTimeout = 0 ) {
 553                 eaccelerator_lock( $key );
 554                 return true;
 555         }
 556
 557         function unlock($key) {
 558                 eaccelerator_unlock( $key );
 559                 return true;
 560         }
 561 }
 562
 563 class DBABagOStuff extends BagOStuff {
 564         var $mHandler, $mFile, $mReader, $mWriter, $mDisabled;
 565
 566         function __construct( $handler = 'db3', $dir = false ) {
 567                 if ( $dir === false ) {
 568                         global $wgTmpDirectory;
 569                         $dir = $wgTmpDirectory;
 570                 }
 571                 $this->mFile = "$dir/mw-cache-" . wfWikiID();
 572                 $this->mFile .= '.db';
 573                 $this->mHandler = $handler;
 574         }
 575
 576         /**
 577          * Encode value and expiry for storage
 578          */
 579         function encode( $value, $expiry ) {
 580                 # Convert to absolute time
 581                 $expiry = BagOStuff::convertExpiry( $expiry );
 582                 return sprintf( '%010u', intval( $expiry ) ) . ' ' . serialize( $value );
 583         }
 584
 585         /**
 586          * @return list containing value first and expiry second
 587          */
 588         function decode( $blob ) {
 589                 if ( !is_string( $blob ) ) {
 590                         return array( null, 0 );
 591                 } else {
 592                         return array(
 593                                 unserialize( substr( $blob, 11 ) ),
 594                                 intval( substr( $blob, 0, 10 ) )
 595                         );
 596                 }
 597         }
 598
 599         function getReader() {
 600                 if ( file_exists( $this->mFile ) ) {
 601                         $handle = dba_open( $this->mFile, 'rl', $this->mHandler );
 602                 } else {
 603                         $handle = $this->getWriter();
 604                 }
 605                 if ( !$handle ) {
 606                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 607                 }
 608                 return $handle;
 609         }
 610
 611         function getWriter() {
 612                 $handle = dba_open( $this->mFile, 'cl', $this->mHandler );
 613                 if ( !$handle ) {
 614                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 615                 }
 616                 return $handle;
 617         }
 618
 619         function get( $key ) {
 620                 wfProfileIn( __METHOD__ );
 621                 wfDebug( __METHOD__."($key)\n" );
 622                 $handle = $this->getReader();
 623                 if ( !$handle ) {
 624                         return null;
 625                 }
 626                 $val = dba_fetch( $key, $handle );
 627                 list( $val, $expiry ) = $this->decode( $val );
 628                 # Must close ASAP because locks are held
 629                 dba_close( $handle );
 630
 631                 if ( !is_null( $val ) && $expiry && $expiry < time() ) {
 632                         # Key is expired, delete it
 633                         $handle = $this->getWriter();
 634                         dba_delete( $key, $handle );
 635                         dba_close( $handle );
 636                         wfDebug( __METHOD__.": $key expired\n" );
 637                         $val = null;
 638                 }
 639                 wfProfileOut( __METHOD__ );
 640                 return $val;
 641         }
 642
 643         function set( $key, $value, $exptime=0 ) {
 644                 wfProfileIn( __METHOD__ );
 645                 wfDebug( __METHOD__."($key)\n" );
 646                 $blob = $this->encode( $value, $exptime );
 647                 $handle = $this->getWriter();
 648                 if ( !$handle ) {
 649                         return false;
 650                 }
 651                 $ret = dba_replace( $key, $blob, $handle );
 652                 dba_close( $handle );
 653                 wfProfileOut( __METHOD__ );
 654                 return $ret;
 655         }
 656
 657         function delete( $key, $time = 0 ) {
 658                 wfProfileIn( __METHOD__ );
 659                 $handle = $this->getWriter();
 660                 if ( !$handle ) {
 661                         return false;
 662                 }
 663                 $ret = dba_delete( $key, $handle );
 664                 dba_close( $handle );
 665                 wfProfileOut( __METHOD__ );
 666                 return $ret;
 667         }
 668
 669         function add( $key, $value, $exptime = 0 ) {
 670                 wfProfileIn( __METHOD__ );
 671                 $blob = $this->encode( $value, $exptime );
 672                 $handle = $this->getWriter();
 673                 if ( !$handle ) {
 674                         return false;
 675                 }
 676                 $ret = dba_insert( $key, $blob, $handle );
 677                 # Insert failed, check to see if it failed due to an expired key
 678                 if ( !$ret ) {
 679                         list( $value, $expiry ) = $this->decode( dba_fetch( $key, $handle ) );
 680                         if ( $expiry < time() ) {
 681                                 # Yes expired, delete and try again
 682                                 dba_delete( $key, $handle );
 683                                 $ret = dba_insert( $key, $blob, $handle );
 684                                 # This time if it failed then it will be handled by the caller like any other race
 685                         }
 686                 }
 687
 688                 dba_close( $handle );
 689                 wfProfileOut( __METHOD__ );
 690                 return $ret;
 691         }
 692 }
 693
 694 ?>